Horticulturae

17 pages, 2225 KiB

Open AccessEditor’s ChoiceArticle

Screening of Suitable Plant Regeneration Protocols for Several Capsicum spp. through Direct Organogenesis

by Marina Martínez-López, Ana García-Pérez, Esther Gimeno-Páez, Jaime Prohens, Santiago Vilanova and Edgar García-Fortea

Horticulturae 2021, 7(9), 261; https://doi.org/10.3390/horticulturae7090261 - 25 Aug 2021

Cited by 3 | Viewed by 3377

Abstract

Peppers (Capsicum spp.) are recalcitrant to in vitro culture regeneration, making the application of in vitro-based breeding strategies difficult. We evaluated the impact of different combinations of auxins, cytokinins and micronutrients on the induction of direct organogenesis in cotyledon and hypocotyl explants [...] Read more.

Peppers (Capsicum spp.) are recalcitrant to in vitro culture regeneration, making the application of in vitro-based breeding strategies difficult. We evaluated the impact of different combinations of auxins, cytokinins and micronutrients on the induction of direct organogenesis in cotyledon and hypocotyl explants of C. annuum, C. baccatum and C. chinense. We found variation in the regeneration response among species and type of explant. In this way, the average numbers of shoots per cotyledon and hypocotyl explant were, respectively, 1.44 and 0.28 for C. annuum, 4.17 and 3.20 for C. baccatum and 0.08 and 0.00 for C. chinense. Out of the six media, the best overall results were obtained with the medium Pep1, which contained 5 mg/L BAP (6-benzylaminopurine), 0.5 mg/L IAA (indole-3-acetic acid) and 0.47 mg/L CuSO₄, followed by a subculture in the same medium supplemented with 10 mg/L AgNO₃ (medium Pep1.2). The best result for the Pep1 + Pep1.2 medium was obtained for C. baccatum using cotyledon explants, with 8.87 shoots per explant. The explants grown in medium Pep1 + Pep1.2 were the ones with greener tissue, while overall the hypocotyl explants were greener than the cotyledon explants. Our results indicate that there is wide variation among Capsicum species in terms of regeneration. Our results suggest that the synergistic effect of copper and silver resulted in a higher regeneration rate of Capsicum explants. Explants with shoots were transferred to different media for elongation, rooting and acclimatization. Although acclimatized plantlets were obtained for C. baccatum and C. chinense, an improvement in these latter stages would be desirable for a high throughput regeneration pipeline. This work contributes to the improvement of Capsicum regeneration protocols using specific combinations of medium, explant and genotype, reaching the levels of efficiency required for genetic transformation and of gene editing technologies for other crops. Full article

(This article belongs to the Collection Application of Tissue Culture to Horticulture)

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13 pages, 500 KiB

Open AccessEditor’s ChoiceArticle

Silicon Foliar Spray and Substrate Drench Effects on Plant Growth, Morphology, and Resistance to Wilting with Container-Grown Edible Species

by Joshua B. Tebow, Lauren L. Houston and Ryan W. Dickson

Horticulturae 2021, 7(9), 263; https://doi.org/10.3390/horticulturae7090263 - 25 Aug 2021

Cited by 5 | Viewed by 2757

Abstract

The objective of this study was to evaluate silicon (Si) foliar spray and substrate drench effects on plant growth and morphology for container-grown edible crops during greenhouse production, as well as resistance to plant wilting during post-production. In the first greenhouse experiment, basil [...] Read more.

The objective of this study was to evaluate silicon (Si) foliar spray and substrate drench effects on plant growth and morphology for container-grown edible crops during greenhouse production, as well as resistance to plant wilting during post-production. In the first greenhouse experiment, basil received Si foliar sprays at 0, 50, 100, 200, and 400 mg∙L^–1 Si. In the second greenhouse experiment, Si was applied as either a foliar spray (500 mg∙L^–1 Si) or substrate drench (100 mg∙L^–1 Si) with six edible crop species. Supplemental Si increased shoot Si levels but had minimal effects on plant growth and morphology, except for parsley, which resulted in distorted growth and phytotoxicity. In the first experiment, 200 and 400 mg∙L^–1 Si foliar sprays increased plant resistance to wilt by 2.2 and 2.5 d, respectively; however, this was not observed in the second experiment. All species accumulated Si with the control (no Si) treatments, indicating trace amounts of Si were taken up from the substrate, fertilizer, spray surfactant, and irrigation water. Only cucumber was classified as a Si “accumulator” with a high capacity for Si uptake. Results emphasize the need to conduct preliminary trials with supplemental Si to avoid issues of phytotoxicity. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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18 pages, 927 KiB

Open AccessEditor’s ChoiceArticle

Interactive Effects of Arbuscular Mycorrhizal Inoculation with Nano Boron, Zinc, and Molybdenum Fertilization on Stevioside Contents of Stevia (Stevia rebaudiana, L.) Plants

by Reda M. Y. Zewail, Maha Ali, Ibrahim S. H. El-Gamal, Sherine H. A. Al-Maracy, Khandakar R. Islam, Mohamed Elsadek, Ehab Azab, Adil A. Gobouri, Nihal ElNahhas, Mostafa H. M. Mohamed and Heba S. El-Desouky

Horticulturae 2021, 7(8), 260; https://doi.org/10.3390/horticulturae7080260 - 22 Aug 2021

Cited by 6 | Viewed by 2723

Abstract

Stevia (Stevia rebaudiana, L.) is receiving increasing global interest as a diabetes-focused herb associated with zero-calorie stevioside sweetener glycoside production. This study was conducted to determine whether the arbuscular mycorrhiza (AM), as a biofertilizer integrated with nano boron (B), zinc (Zn), [...] Read more.

Stevia (Stevia rebaudiana, L.) is receiving increasing global interest as a diabetes-focused herb associated with zero-calorie stevioside sweetener glycoside production. This study was conducted to determine whether the arbuscular mycorrhiza (AM), as a biofertilizer integrated with nano boron (B), zinc (Zn), and molybdenum (Mo), would improve stevia growth and stevioside content. A factorial experiment with four replicates was conducted to evaluate the effect of AM at 0, 150, and 300 spore/g soil and three nano microelements B at 100 mg/L, Zn at 100 mg/L, and Mo at 40 mg/L on growth performance, stevioside, mineral contents, and biochemical contents of stevia. Results indicated that the combination of AM at 150 and B at 100 mg/L significantly increased plant height, number of leaves, fresh and dry-stem, and herbal g/plant during the 2019 and 2020 growing seasons. Chlorophyll content was increased by the combination between AM at 150 spore/g soil and B at 100 mg/L during both seasons. Stevioside content in leaves was increased by AM at 150 spore/g soil and B at 100 mg/L during the second season. In addition, N, P, K, Zn, and B in the leaf were increased by applying the combination of AM and nano microelements. Leaf bio constituent contents were increased with AM at 150 spore/g soil and B at 100 mg/L during both seasons. The application of AM and nano B can be exploited for high growth, mineral, and stevioside contents as a low-calorie sweetener product in stevia. Full article

(This article belongs to the Special Issue Recent Advances in Nutrition and Fertilization of Horticultural Crops)

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16 pages, 3420 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

High-Resolution UAV Imagery for Field Olive (Olea europaea L.) Phenotyping

by Giovanni Caruso, Giacomo Palai, Francesco Paolo Marra and Tiziano Caruso

Horticulturae 2021, 7(8), 258; https://doi.org/10.3390/horticulturae7080258 - 21 Aug 2021

Cited by 18 | Viewed by 2587

Abstract

Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. In this study, we [...] Read more.

Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. In this study, we assessed the ability of a UAV equipped with RGB-NIR cameras in highlighting differences in geometrical and spectral canopy characteristics between eight olive cultivars planted at different planting distances in a hedgerow olive orchard. The relationships between measured and estimated canopy height, projected canopy area and canopy volume were linear regardless of the different cultivars and planting distances (RMSE of 0.12 m, 0.44 m² and 0.68 m³, respectively). A good relationship (R² = 0.95) was found between the pruning mass material weighted on the ground and its volume estimated by aerial images. NDVI measured in February 2019 was related to fruit yield per tree measured in November 2018, whereas no relationships were observed with the fruit yield measured in November 2019 due to abiotic and biotic stresses that occurred before harvest. These results confirm the reliability of UAV imagery and structure from motion techniques in estimating the olive geometrical canopy characteristics and suggest further potential applications of UAVs in early discrimination of yield efficiency between different cultivars and in estimating the pruning material volume. Full article

(This article belongs to the Special Issue Precision Management of Fruit Trees)

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20 pages, 285 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Application of Nitrogen Fertilization and Foliar Spraying with Calcium and Boron Affects Growth Aspects, Chemical Composition, Productivity and Fruit Quality of Strawberry Plants

by Mustafa. H. M. Mohamed, Spyridon A. Petropoulos and Maha Mohamed Elsayed Ali

Horticulturae 2021, 7(8), 257; https://doi.org/10.3390/horticulturae7080257 - 21 Aug 2021

Cited by 11 | Viewed by 3875

Abstract

Strawberries are rich in antioxidants and plant components to enhance cardiac health and regulate blood sugar. This experiment investigates the effects of N fertilization and foliar spraying with calcium (Ca) and boron (B) on growth, chemical composition of plant foliage, fruit yield, and [...] Read more.

Strawberries are rich in antioxidants and plant components to enhance cardiac health and regulate blood sugar. This experiment investigates the effects of N fertilization and foliar spraying with calcium (Ca) and boron (B) on growth, chemical composition of plant foliage, fruit yield, and quality of strawberry plants (Fragaria × ananassa Duch. cv. Fortuna). This experiment includes 12 treatments from the combination between four N fertilizers treatments (combinations of mineral and organic fertilizers) and three foliar spraying treatments with Ca+B at 2 and 4 mL/L in addition to the control treatment (spraying with tap water). Results show that the treatment where 50% of the recommended dose of N (50% RDN) was applied with mineral fertilizer + 100% organic N was the most effective one since it induced the highest values of plant height, number of crowns per plant, number of leaves per plant, fresh and dry weight per plant, especially when combined with the foliar application of Ca+B at the highest tested rate (4 mL/L). The highest values of N, P, K, Ca, B, and total carbohydrate contents were also scored for the combination of 50% RDN + 100% organic N and the foliar spraying with Ca+B at 4 mL/L in both growing seasons. In addition, the highest values of fruit yield per plant and per hectare, exportable fruit yield/ha, fruit firmness, fruit TSS, Vitamin C, total sugars, and anthocyanin, as well as the lowest values of total acidity were recorded for the combined treatment of 50% RDN + 100% organic and Ca+B at the highest rate (4 mL/L). The highest recorded value of length, diameter, and weight of fruit were scored by fertilizing strawberry plants with the recommended dose of mineral N (100% RDN) and spraying with Ca+B at the highest rate in both growing seasons. In conclusion, it could be suggested that fertilization of strawberry plants with half the recommended dose with mineral N fertilizer + 100% organic fertilizer and foliar spraying with Ca+B at 4 mL/L increases plant growth and improve yield parameters and fruit quality of the strawberry plants. Full article

(This article belongs to the Special Issue Physico-Chemical Characterization of Fruits and Vegetables)

13 pages, 4484 KiB

Open AccessEditor’s ChoiceArticle

Spatial Variability of Production and Quality in Table Grapes ‘Flame Seedless’ Growing on a Flat Terrain and Slope Site

by Nicolás Verdugo-Vásquez, Emilio Villalobos-Soublett, Gastón Gutiérrez-Gamboa and Miguel Araya-Alman

Horticulturae 2021, 7(8), 254; https://doi.org/10.3390/horticulturae7080254 - 19 Aug 2021

Cited by 2 | Viewed by 2166

Abstract

(1) Background: Precision agriculture has been used mostly to study spatial variability in vineyards for winemaking. Nevertheless, there is little available information on the impacts of its use on table grape vineyards under different slope conditions. (2) Methods: The aim was to study [...] Read more.

(1) Background: Precision agriculture has been used mostly to study spatial variability in vineyards for winemaking. Nevertheless, there is little available information on the impacts of its use on table grape vineyards under different slope conditions. (2) Methods: The aim was to study the spatial variability of production and berry quality in ‘Flame Seedless’ vines established on a flat (3% slope) and sloping (23% slope) terrain in the Chilean hyper-arid northern region. (3) Results: The results showed that in both vineyards, the measured variables presented a high spatial variability according to their coefficient of variation, being higher in slope than in the flat vineyard. The geostatistical analysis showed that 82% of the measured variables presented a strong spatial dependence in the slope vineyard, whereas 45% and 55% of the variables measured in the flat vineyard presented strong and moderate spatial dependence, respectively. Elevation was related to berry quality parameters in both vineyards, while trunk vine circumference was related to berry quality for the slope vineyard and to yield for the flat vineyard. (4) Conclusions: There is an important spatial variability in table grape vineyards mostly those cultivated on slope sites. Therefore, precision agriculture tools can be useful for zoning table grape vineyards, and thus improving both economic returns of viticulturists and sustainability. Full article

(This article belongs to the Section Viticulture)

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4 pages, 670 KiB

Open AccessEditor’s ChoicePerspective

Digitalization of Clubroot Disease Index, a Long Overdue Task

by Rasha Salih and Edel Pérez-López

Horticulturae 2021, 7(8), 241; https://doi.org/10.3390/horticulturae7080241 - 12 Aug 2021

Cited by 2 | Viewed by 3014

Abstract

Clubroot is a devastating disease caused by the protist Plasmodiophora brassicae Woronin. After root hair colonization, the clubroot pathogen induces clubs that block water uptake, leading to dehydration and death. The study of the severity of plant diseases is very important. It allows [...] Read more.

Clubroot is a devastating disease caused by the protist Plasmodiophora brassicae Woronin. After root hair colonization, the clubroot pathogen induces clubs that block water uptake, leading to dehydration and death. The study of the severity of plant diseases is very important. It allows us to characterize the level of resistance of plant germplasm and to classify the virulence of pathogen strains or isolates. Lately, the use of learning machines and automatization has expanded to plant pathology. Fast, reliable and unbiased methods are always necessary, and with clubroot disease indexing this is not different. From this perspective, we discuss why this is the case and how we could achieve this long overdue task for clubroot disease. Full article

(This article belongs to the Special Issue Soil-Borne Obligate Parasite of Brassicaceae)

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26 pages, 448 KiB

Open AccessEditor’s ChoiceReview

Environmental and Cultivation Factors Affect the Morphology, Architecture and Performance of Root Systems in Soilless Grown Plants

by Astrit Balliu, Youbin Zheng, Glenda Sallaku, Juan A. Fernández, Nazim S. Gruda and Yuksel Tuzel

Horticulturae 2021, 7(8), 243; https://doi.org/10.3390/horticulturae7080243 - 12 Aug 2021

Cited by 38 | Viewed by 8781

Abstract

Soilless culture systems are currently one of the fastest-growing sectors in horticulture. The plant roots are confined into a specific rootzone and are exposed to environmental changes and cultivation factors. The recent scientific evidence regarding the effects of several environmental and cultivation factors [...] Read more.

Soilless culture systems are currently one of the fastest-growing sectors in horticulture. The plant roots are confined into a specific rootzone and are exposed to environmental changes and cultivation factors. The recent scientific evidence regarding the effects of several environmental and cultivation factors on the morphology, architecture, and performance of the root system of plants grown in SCS are the objectives of this study. The effect of root restriction, nutrient solution, irrigation frequency, rootzone temperature, oxygenation, vapour pressure deficit, lighting, rootzone pH, root exudates, CO₂, and beneficiary microorganisms on the functionality and performance of the root system are discussed. Overall, the main results of this review demonstrate that researchers have carried out great efforts in innovation to optimize SCS water and nutrients supply, proper temperature, and oxygen levels at the rootzone and effective plant–beneficiary microorganisms, while contributing to plant yields. Finally, this review analyses the new trends based on emerging technologies and various tools that might be exploited in a smart agriculture approach to improve root management in soilless cropping while procuring a deeper understanding of plant root–shoot communication. Full article

(This article belongs to the Special Issue Optimising Soilless Culture Systems and Alternative Growing Media to Current Used Materials)

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18 pages, 5419 KiB

Open AccessEditor’s ChoiceArticle

Investigating the Molecular Mechanisms of Pepper Fruit Tolerance to Storage via Transcriptomics and Metabolomics

by Hao Sun, Qing Li, Lian-Zhen Mao, Qiao-Ling Yuan, Yu Huang, Meng Chen, Can-Fang Fu, Xuan-Hua Zhao, Zi-Yu Li, Yun-Hua Dai, Xue-Xiao Zou and Li-Jun Ou

Horticulturae 2021, 7(8), 242; https://doi.org/10.3390/horticulturae7080242 - 12 Aug 2021

Cited by 2 | Viewed by 2501

Abstract

Pepper is one of the most important vegetable crops in China and has high economic value. However, the pepper fruit is easily softened and spoiled after harvest, which seriously affects its flavor, transportation, and economic value. In this study, we used pepper lines [...] Read more.

Pepper is one of the most important vegetable crops in China and has high economic value. However, the pepper fruit is easily softened and spoiled after harvest, which seriously affects its flavor, transportation, and economic value. In this study, we used pepper lines with different levels of storage resistance, A144 and A361, and performed physiological examination, transcriptomics, and metabolomics on them at 0 and 3 days after harvest in order to analyze their gene expression patterns and molecular regulatory mechanisms for storage tolerance. A total of 23,477 genes and 985 metabolites were identified. After comparing and analyzing each sample, we identified 7829 differentially expressed genes and 296 differential metabolites. We found that the genes such as ethylene-responsive transcriptional factor (ERFs), polygalacturonase (PG), cellulose synthase (CESA), abscisic acid insensitive (ABI), protein kinase 2 (SnRK2), and protein phosphatase 2C (PP2C) and metabolites such as phenylalanine and glycyl-tyrosine were differentially expressed between different storage times in the two materials. Through GO and KEGG enrichment analysis, we found that the differential genes were mainly enriched in carbohydrate metabolism, small molecule metabolism, and plant hormone signal transduction, and the differential metabolites were mainly enriched in flavonoid biosynthesis, glutathione metabolism, and cysteine and methionine metabolism pathways. This study provides a scientific basis for investigating the molecular mechanisms of storage tolerance and developing new pepper varieties with improved storage resistance. Full article

(This article belongs to the Collection Postharvest Handling of Horticultural Crops)

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13 pages, 262 KiB

Open AccessEditor’s ChoiceArticle

Rootstocks Impact Yield, Fruit Composition, Nutrient Deficiencies, and Winter Survival of Hybrid Cultivars in Eastern Canada

by Caroline Provost, Alexander Campbell and François Dumont

Horticulturae 2021, 7(8), 237; https://doi.org/10.3390/horticulturae7080237 - 10 Aug 2021

Cited by 7 | Viewed by 2604

Abstract

Grafting cold-hardy hybrid grapevines may influence their attributes under different pedoclimatic conditions and may also contribute to cold-hardiness, influence plant physiology, and affect yield and fruit composition. In a six-year study, we evaluated bud survival, plant development, nutrient deficiencies, yield, and fruit composition [...] Read more.

Grafting cold-hardy hybrid grapevines may influence their attributes under different pedoclimatic conditions and may also contribute to cold-hardiness, influence plant physiology, and affect yield and fruit composition. In a six-year study, we evaluated bud survival, plant development, nutrient deficiencies, yield, and fruit composition for three cold-hardy grape varieties: Frontenac, Frontenac blanc, and Marquette. The grape varieties were grafted on four rootstocks: 3309C, SO4, Riparia Gloire, and 101-14. The final combinations were own-rooted. The six-year research period indicated that cold-hardy hybrids were affected differently by each rootstock. Magnesium deficiency was lower for grafted Frontenac and Frontenac blanc compared with own-rooted vines, but bud survival and grapevine development were not affected by rootstock. Moreover, results related to yield components showed that there are significant differences between rootstocks and own-rooted vines. Frontenac was the least affected grape variety compared to Frontenac blanc and Marquette, where only cluster weight and berry weight were impacted. Overall, for the two Frontenac varietals, we also observed a greater maturity for fruits of vines grafted on 101-14 and 3309C compared with own-rooted vines. Grafting affected fruit composition for Marquette differently, where the lowest grape maturity was observed for fruits on vines grafted on SO4. This study demonstrates that rootstocks affect cold-hardy hybrids, highlighting their potential under eastern North American conditions. Full article

(This article belongs to the Special Issue Advances in Viticulture Production)

11 pages, 699 KiB

Open AccessEditor’s ChoiceArticle

Effect of Magnetic Treatment of Water or Seeds on Germination and Productivity of Tomato Plants under Salinity Stress

by Nezar Husein Samarah, Mu’awia Muhsen Ibrahim Bany Hani and Ibrahim Mahmoud Makhadmeh

Horticulturae 2021, 7(8), 220; https://doi.org/10.3390/horticulturae7080220 - 3 Aug 2021

Cited by 10 | Viewed by 3318

Abstract

Salinity is an abiotic stress that reduces the seed germination and productivity of tomatoes. Magnetic treatment has been shown to have a positive effect on the seed germination, seedling growth, and productivity of various crop species. Therefore, three experiments were conducted to evaluate [...] Read more.

Salinity is an abiotic stress that reduces the seed germination and productivity of tomatoes. Magnetic treatment has been shown to have a positive effect on the seed germination, seedling growth, and productivity of various crop species. Therefore, three experiments were conducted to evaluate whether treating saline water or seeds with a magnetic field can improve the seed germination and productivity of tomatoes (Solanum lycopersicum) under salinity stress. To evaluate seed germination and seedling growth in response to a magnetic field, two laboratory experiments were carried out by passing four saline water solutions of NaCl (0, 5, 10, and 15 dS/m) through a magnetic field (3.5–136 mT) or exposing tomato seeds to the same magnetic field for 20 min before sowing. In a greenhouse experiment, plants were irrigated with different magnetically-treated and untreated saline water solutions to evaluate plant growth. Magnetic treatment of water or seeds improved seed germination percentage, speed of germination (lower mean time to germination), and seedling length and dry weight in the two laboratory experiments, especially under salinity stress of 5 and 10 dS/m. As the salinity level increased, germination performance and plant growth were significantly decreased. Irrigating tomato plants with magnetically-treated water improved plant height, stem diameter, and fruit yield per plant compared to untreated water, especially under salinity of 0 and 5 dS/m. In conclusion, magnetic treatment of saline water or seeds improved germination performance, plant growth, and fruit yield of tomatoes under saline conditions. Full article

(This article belongs to the Section Biotic and Abiotic Stress)

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16 pages, 3621 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Assessing the Potential of the Terrestrial Cyanobacterium Anabaena minutissima for Controlling Botrytis cinerea on Tomato Fruits

by Hillary Righini, Ornella Francioso, Michele Di Foggia, Antera Martel Quintana and Roberta Roberti

Horticulturae 2021, 7(8), 210; https://doi.org/10.3390/horticulturae7080210 - 23 Jul 2021

Cited by 6 | Viewed by 2384

Abstract

Cyanobacteria are oxygenic phototrophs that have an essential role in soil N₂ fixation, fertility, and water retention. Cyanobacteria are also natural sources of bioactive metabolites beneficial to improve plant vigor and potentially active against fungal plant pathogens. Therefore, we studied the antifungal [...] Read more.

Cyanobacteria are oxygenic phototrophs that have an essential role in soil N₂ fixation, fertility, and water retention. Cyanobacteria are also natural sources of bioactive metabolites beneficial to improve plant vigor and potentially active against fungal plant pathogens. Therefore, we studied the antifungal activity of water extract (WE) and phycobiliproteins (PBPs) from Anabaena minutissima strain BEA 0300B against the fungal plant pathogen Botrytis cinerea on tomato fruits and in vitro. The water extract and PBPs were characterized by using FT-IR and FT-Raman spectroscopies. Both water extract (5 mg/mL) and PBPs (ranged from 0.3 to 4.8 mg/mL) reduced disease incidence and disease severity on tomato fruits and mycelium growth and colony forming units in vitro. For mycelium growth, a linear PBP dose-response was found. Tomato fruits were also characterized by FT-IR and FT-Raman spectroscopies in order to evaluate structural modifications induced by pathogen and PBP treatment. PBPs preserved cutin and pectin structures by pathogen challenge. In conclusion, A. minutissima can be considered a potential tool for future large-scale experiments for plant disease control. Full article

(This article belongs to the Special Issue Explorations in Postharvest Diseases of Fruits and Vegetables)

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11 pages, 309 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Productive and Morphometric Traits, Mineral Composition and Secondary Metabolome Components of Borage and Purslane as Underutilized Species for Microgreens Production

by Giandomenico Corrado, Christophe El-Nakhel, Giulia Graziani, Antonio Pannico, Armando Zarrelli, Paola Giannini, Alberto Ritieni, Stefania De Pascale, Marios C. Kyriacou and Youssef Rouphael

Horticulturae 2021, 7(8), 211; https://doi.org/10.3390/horticulturae7080211 - 23 Jul 2021

Cited by 19 | Viewed by 2465

Abstract

Neglected and underutilized species (NUS) offer largely unexplored opportunities for providing nutritious plant food, while making agro-ecosystems more diverse and resilient to climate change. The aim of this work was to explore the potential of two typical Mediterranean underutilized species, purslane and borage, [...] Read more.

Neglected and underutilized species (NUS) offer largely unexplored opportunities for providing nutritious plant food, while making agro-ecosystems more diverse and resilient to climate change. The aim of this work was to explore the potential of two typical Mediterranean underutilized species, purslane and borage, as novel vegetable product (microgreens). Micro-scale production of edible plants is spreading due to the simplicity of their management, rapid cycle, harvest index, and phytochemical value of the edible product. Microgreens, therefore, represent an opportunity to link NUS, nutrition, and agricultural and dietary diversification. By analyzing yield, antioxidants activities, mineral composition, and main phenolic acids and flavonoids, our work indicated that the two species provide interesting results when compared with those reported for crops and horticultural species. Specifically, purslane should be considered highly nutritional due to the amount of phenolic compounds and ascorbic acid, and to potential good β-carotene bioavailability. Borage microgreens have a very high fresh yield and a more composite and balanced phenolic profile. In conclusion, our work provided evidence for implementing new ways to expand the NUS market-chains and for developing added-value food products. Full article

(This article belongs to the Special Issue Neglected and Underutilized Plant Species in Horticultural and Ornamental Systems: Perspectives for Biodiversity, Nutraceuticals and Agricultural Sustainability)

14 pages, 2081 KiB

Open AccessEditor’s ChoiceArticle

Cucumis melo L. Germplasm in Tunisia: Unexploited Sources of Resistance to Fusarium Wilt

by Hela Chikh-Rouhou, Maria Luisa Gómez-Guillamón, Vicente González, Rafika Sta-Baba and Ana Garcés-Claver

Horticulturae 2021, 7(8), 208; https://doi.org/10.3390/horticulturae7080208 - 22 Jul 2021

Cited by 8 | Viewed by 3364

Abstract

Breeding for disease resistance has been one of the most important research objectives in melon for the last few decades. Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (Fom) is among the most threatening melon fungal diseases along the Mediterranean [...] Read more.

Breeding for disease resistance has been one of the most important research objectives in melon for the last few decades. Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (Fom) is among the most threatening melon fungal diseases along the Mediterranean coast, affecting yield and quality. Since genetic resistance is one of the best sustainable strategies that can be used to control this pathogen, 27 Tunisian melon accessions collected from local farmers have been tested using phenotypic and molecular approaches to identify new sources of resistance to be used directly as cultivars in affected areas or as resistance donors in breeding programs. The phenotypic evaluations, using artificial inoculations, showed several resistant accessions to the pathogenic races of Fom. Additionally, molecular analysis revealed that 13 out of 27 accessions carried the resistance Fom-1 gene (7 in homozygous state and 6 in heterozygous state), confirming their resistance to races 0 and 2. Two of them were also identified as heterozygous for the Fom-2 gene, being resistant to races 0 and 1. Furthermore, two accessions with a high level of resistance to the most virulent race 1.2 have been also reported. This melon germplasm should be explored as a potential source of resistance genes in breeding programs to develop new resistant melon cultivars. Full article

(This article belongs to the Special Issue The Effect of Plant Pathogens on Horticultural Plants)

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24 pages, 4149 KiB

Open AccessEditor’s ChoiceArticle

Assessing the Effects of Vineyard Soil Management on Downy and Powdery Mildew Development

by Ana Fernandes de Oliveira, Salvatorica Serra, Virna Ligios, Daniela Satta and Giovanni Nieddu

Horticulturae 2021, 7(8), 209; https://doi.org/10.3390/horticulturae7080209 - 22 Jul 2021

Cited by 7 | Viewed by 2629

Abstract

Advantages of vineyard cover crops include soil conservation, nutrient and water cycling, and a better growth–yield balance. They naturally promote agro-system biological multifunctionality, soil biocenosis, and biological pest control. However, for the role of cover crops on disease control, there is still a [...] Read more.

Advantages of vineyard cover crops include soil conservation, nutrient and water cycling, and a better growth–yield balance. They naturally promote agro-system biological multifunctionality, soil biocenosis, and biological pest control. However, for the role of cover crops on disease control, there is still a lack of information. We performed a systematic evaluation of the soil management effects on the development of two main pathogens: Plasmopara viticola and Erysiphe necator. Conventional soil tillage was compared to grass and legume cover crops during a three-season trial in the Nurra wine region (Sardinia, Italy). Disease and grapevine development were assessed in relation to the weather, leaf area growth, leaf nitrogen, canopy density, and favorable microclimatic conditions for each disease, to weight their importance on disease susceptibility in each treatment. Higher infection percentages were observed in plots subjected to soil tillage. Disease development was better understood in relation to leaf area, leaf nitrogen, and canopy density. The main role of weather conditions on downy mildew infections was ascertained, yet high canopy sunlight levels reduced disease spread under grass cover. For powdery mildew, leaf nitrogen had a crucial role in disease development under soil tillage, and canopy light and hygrothermal conditions had the most relevant function on disease development in cover-cropped vineyards. Full article

(This article belongs to the Special Issue Grape Responses to Abiotic and Biotic Stresses)

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12 pages, 4815 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Biological Control of Pear Valsa Canker Caused by Valsa pyri Using Penicillium citrinum

by Hongbo Yuan, Bingke Shi, Tianxiang Huang, Zengqiang Zhou, Li Wang, Hui Hou and Hongtao Tu

Horticulturae 2021, 7(7), 198; https://doi.org/10.3390/horticulturae7070198 - 16 Jul 2021

Cited by 10 | Viewed by 2653

Abstract

Valsa canker caused by Valsa pyri is one of the most destructive diseases of commercial pear. For the present analysis, 29 different endophytic fungal strains were isolated from the branches of a healthy pear tree. In dual culture assays, strain ZZ1 exhibited robust [...] Read more.

Valsa canker caused by Valsa pyri is one of the most destructive diseases of commercial pear. For the present analysis, 29 different endophytic fungal strains were isolated from the branches of a healthy pear tree. In dual culture assays, strain ZZ1 exhibited robust antifungal activity against all tested pathogens including Valsa pyri. Microscopic analyses suggested that following co-culture with ZZ1, the hyphae of V. pyri were ragged, thin, and ruptured. ZZ1 also induced significant decreases in lesion length and disease incidence on detached pear branches inoculated with V. pyri. ZZ1 isolate-derived culture filtrates also exhibited antifungal activity against V. pyri, decreasing mycelial growth and conidium germination and inhibiting V. pyri-associated lesion development on pear branches. These results suggest that the ZZ1 isolate has the potential for use as a biological control agent against V. pyri. The strain was further identified as Penicillium citrinum based on its morphological characteristics and molecular analyses. Overall, these data highlight a potentially valuable new biocontrol resource for combating pear Valsa canker. Full article

(This article belongs to the Section Plant Pathology and Disease Management (PPDM))

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17 pages, 1300 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Twenty-Years of Hop Irrigation by Flooding the Inter-Row Did Not Cause a Gradient along the Row in Soil Properties, Plant Elemental Composition and Dry Matter Yield

by Sandra Afonso, Margarida Arrobas and Manuel Ângelo Rodrigues

Horticulturae 2021, 7(7), 194; https://doi.org/10.3390/horticulturae7070194 - 15 Jul 2021

Cited by 4 | Viewed by 2168

Abstract

In hops (Humulus lupulus L.), irrigation by flooding the inter-row can carry away suspended particles and minerals, causing gradients in soil fertility. The effect of more than 20 years of flooding irrigation on soil and plants was evaluated in two hop fields [...] Read more.

In hops (Humulus lupulus L.), irrigation by flooding the inter-row can carry away suspended particles and minerals, causing gradients in soil fertility. The effect of more than 20 years of flooding irrigation on soil and plants was evaluated in two hop fields by measuring soil and plant variables in multiple points along the rows. In a second experiment 1000 kg ha⁻¹ of lime was applied and incorporated into the soil to assess whether liming could moderate any gradient created by the irrigation. At different sampling points along the rows, significant differences were recorded in soil properties, plant elemental composition and dry matter yield, but this was not found to exist over a continuous gradient. The variations in cone yield were over 50% when different sampling points were compared. However, this difference cannot be attributed to the effect of irrigation, but rather to an erratic spatial variation in some of the soil constituents, such as sand, silt and clay. Flooding irrigation and frequent soil tillage resulted in lower porosity and higher soil bulk density in the 0.0–0.10 m soil layer in comparison to the 0.10–0.20 m layer. In turn, porosity and bulk density were respectively positively and negatively associated with crop productivity. Thus, irrigation and soil tillage may have damaged the soil condition but did not create any gradient along the row. The ridge appeared to provide an important pool of nutrients, probably caused by mass flow due to the evaporation from it and a regular supply of irrigation water to the inter-row. Liming raised the soil pH slightly, but had a relevant effect on neither soil nor plants, perhaps because of the small amounts of lime applied. Full article

(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants)

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15 pages, 4148 KiB

Open AccessEditor’s ChoiceArticle

Effects of Fruit Load on Sugar/Acid Quality and Puffiness of Delayed-Harvest Citrus

by Fangjie Xu, Haishan An, Jiaying Zhang, Zhihong Xu and Fei Jiang

Horticulturae 2021, 7(7), 189; https://doi.org/10.3390/horticulturae7070189 - 10 Jul 2021

Cited by 7 | Viewed by 2646

Abstract

Delayed harvesting technology is believed to improve the citrus fruit flavor, but improper tree fruit load under delayed harvest might cause puffiness and reduce fruit quality. In order to find out an optimum tree fruit load level to obtain better flavor quality as [...] Read more.

Delayed harvesting technology is believed to improve the citrus fruit flavor, but improper tree fruit load under delayed harvest might cause puffiness and reduce fruit quality. In order to find out an optimum tree fruit load level to obtain better flavor quality as well as reduce puffiness in delayed-harvest citrus under protected cultivation, experiments were conducted in the present study between 2019 and 2020 to determine the effect of different fruit loads and fruit-bearing per single branch on the soluble sugars and organic acids metabolism in the peel and flesh, the anatomical structure of the matured fruit peel, and fruit texture-related indexes. The results suggested significant negative correlations between leaf N level and flesh sucrose and glucose contents, and between branch P level and flesh citric acid contents; no significant correlation between NPK levels and flesh texture; relatively lower leaf N and branch P under relatively higher load can increase flesh sucrose and glucose accumulation and slow down citric acid degradation to the greater extent, thus optimizing the sugar/acid ratio of fruits during delayed harvest. The lignification of parenchyma cells closely around peel secretory cavities due to ascorbic acid deficiency might be the primary cause for puffiness under low-load treatments. Full article

(This article belongs to the Collection Advances in Fruit Quality Formation and Regulation)

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12 pages, 1260 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Horseradish: A Neglected and Underutilized Plant Species for Improving Human Health

by Stuart Alan Walters

Horticulturae 2021, 7(7), 167; https://doi.org/10.3390/horticulturae7070167 - 29 Jun 2021

Cited by 7 | Viewed by 9329

Abstract

Horseradish is a flavorful pungent herb that has been used for centuries to enhance the flavor of food, aid in digestion, and improve human health. Horseradish is a neglected and underutilized plant species (NUS), especially concerning the potential benefits to improve human health. [...] Read more.

Horseradish is a flavorful pungent herb that has been used for centuries to enhance the flavor of food, aid in digestion, and improve human health. Horseradish is a neglected and underutilized plant species (NUS), especially concerning the potential benefits to improve human health. The roots of this plant have been known for centuries to provide effective treatments for various human health disorders and has a long history of use in traditional medicine. Horseradish is a source of many biologically active compounds and its richness in phytochemicals has encouraged its recent use as a functional food. The medicinal benefits of horseradish are numerous, and this plant should be promoted more as being beneficial for human health. Glucosinolates or their breakdown products, isothiocyanates, are responsible for most of the claimed medicinal effects. Recent studies have suggested that glucosinolates provide prevention and inhibitory influences on different types of cancer, and horseradish contains high amounts of these compounds. Other medicinal benefits of horseradish include its well-known antibacterial properties that are also attributed to isothiocyanates, and its high content of other antioxidants that benefit human health. Additionally, horseradish contains enzymes that stimulate digestion, regulate bowel movement, and reduce constipation. Horseradish is a species that is vastly underexploited for its abilities as a medicinal plant species for improving human health. The health promoting effects of horseradish are numerous and should be used in an extensive marketing campaign to improve consumption habits. Consumers need to be made more aware of the tremendous health benefits of this plant, which would most likely increase consumption of this valuable NUS. Although horseradish is a highly versatile plant species and holds great potential for improving human health, this plant can also be used to enhance biodiversity in landscapes and food systems, which will also be briefly discussed. Full article

(This article belongs to the Special Issue New Trends and Innovations in Medicinals, Herbs, and Specialty Crops)

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26 pages, 3212 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Sensory Profile, Shelf Life, and Dynamics of Bioactive Compounds during Cold Storage of 17 Edible Flowers

by Sonia Demasi, Maria Gabriella Mellano, Nicole Mélanie Falla, Matteo Caser and Valentina Scariot

Horticulturae 2021, 7(7), 166; https://doi.org/10.3390/horticulturae7070166 - 29 Jun 2021

Cited by 25 | Viewed by 7402

Abstract

In this study, 17 edible flowers (Allium ursinum L., Borago officinalis L., Calendula officinalis L., Centaurea cyanus L., Cichorium intybus L., Dianthus carthusianorum L., Lavandula angustifolia Mill., Leucanthemum vulgare (Vaill.) Lam., Paeonia officinalis L., Primula veris L., Robinia pseudoacacia L., Rosa canina [...] Read more.

In this study, 17 edible flowers (Allium ursinum L., Borago officinalis L., Calendula officinalis L., Centaurea cyanus L., Cichorium intybus L., Dianthus carthusianorum L., Lavandula angustifolia Mill., Leucanthemum vulgare (Vaill.) Lam., Paeonia officinalis L., Primula veris L., Robinia pseudoacacia L., Rosa canina L., Rosa pendulina L., Salvia pratensis L., Sambucus nigra L., Taraxacum officinale Weber, and Tropaeolum majus L.) were investigated to assess their sensory profile at harvest and their shelf life and bioactive compounds dynamics during cold storage. The emerging market of edible flowers lacks this information; thus, the characteristics and requirements of different flower species were provided. In detail, a quantitative descriptive analysis was performed by trained panelists at flower harvest, evaluating 10 sensory descriptors (intensity of sweet, sour, bitter, salt, smell, specific flower aroma, and herbaceous aroma; spiciness, chewiness, and astringency). Flower visual quality, biologically active compounds content (total polyphenols and anthocyanins), and antioxidant activity (FRAP, DPPH, and ABTS assays) were evaluated both at harvest and during storage at 4 °C for 14 days to assess their shelf life. Generally, species had a wide range of peculiar sensory and phytochemical characteristics at harvest, as well as shelf life and bioactive compounds dynamics during postharvest. A strong aroma was indicated for A. ursinum, D. carthusianorum, L. angustifolia, and L. vulgare, while B. officinalis and C. officinalis had very low values for all aroma and taste descriptors, resulting in poor sensory profiles. At harvest, P. officinalis, R. canina, and R. pendulina exhibited the highest values of polyphenols (884–1271 mg of gallic acid equivalents per 100 g) and antioxidant activity (204–274 mmol Fe²⁺/kg for FRAP, 132–232 and 43–58 µmol of Trolox equivalent per g for DPPH and ABTS). The species with the longest shelf life in terms of acceptable visual quality was R. pendulina (14 days), followed by R. canina (10 days). All the other species lasted seven days, except for C. intybus and T. officinale that did not reach day 3. During cold storage, the content of bioactive compounds differed, as total phenolics followed a different trend according to the species and anthocyanins remained almost unaltered for 14 days. Considering antioxidant activity, ABTS values were the least variable, varying in only four species (A. ursinum, D. carthusianorum, L. angustifolia, and P. officinalis), while both DPPH and FRAP values varied in eight species. Taken together, the knowledge of sensory profiles, phytochemical characteristics and shelf life can provide information to select suitable species for the emerging edible flower market. Full article

(This article belongs to the Special Issue Nutritional and Antioxidant Value of Horticulturae Products)

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12 pages, 526 KiB

Open AccessEditor’s ChoiceArticle

Seed Set Patterns in East African Highland Cooking Bananas Are Dependent on Weather before, during and after Pollination

by Allan Waniale, Rony Swennen, Settumba B. Mukasa, Arthur K. Tugume, Jerome Kubiriba, Wilberforce K. Tushemereirwe, Michael Batte, Allan Brown and Robooni Tumuhimbise

Horticulturae 2021, 7(7), 165; https://doi.org/10.3390/horticulturae7070165 - 29 Jun 2021

Cited by 1 | Viewed by 1698

Abstract

Seed set in banana is influenced by weather, yet the key weather attributes and the critical period of influence are unknown. We therefore investigated the influence of weather during floral development for a better perspective of seed set increase. Three East African highland [...] Read more.

Seed set in banana is influenced by weather, yet the key weather attributes and the critical period of influence are unknown. We therefore investigated the influence of weather during floral development for a better perspective of seed set increase. Three East African highland cooking bananas (EAHBs) were pollinated with pollen fertile wild banana ‘Calcutta 4′. At full maturity, bunches were harvested, ripened, and seeds extracted from fruit pulp. Pearson’s correlation analysis was then conducted between seed set per 100 fruits per bunch and weather attributes at 15-day intervals from 105 days before pollination (DBP) to 120 days after pollination (DAP). Seed set was positively correlated with average temperature (P < 0.05–P < 0.001, r = 0.196–0.487) and negatively correlated with relative humidity (RH) (P < 0.05–P < 0.001, r = −0.158–−0.438) between 75 DBP and the time of pollination. After pollination, average temperature was negatively correlated with seed set in ‘Mshale’ and ‘Nshonowa’ from 45 to 120 DAP (P < 0.05–P < 0.001, r = −0.213–−0.340). Correlation coefficients were highest at 15 DBP for ‘Mshale’ and ‘Nshonowa’, whereas for ‘Enzirabahima’, the highest were at the time of pollination. Maximum temperature as revealed by principal component analysis at the time of pollination should be the main focus for seed set increase. Full article

(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))

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15 pages, 41997 KiB

Open AccessEditor’s ChoiceArticle

Effect of Postharvest Transport and Storage on Color and Firmness Quality of Tomato

by Mai Al-Dairi, Pankaj B. Pathare and Rashid Al-Yahyai

Horticulturae 2021, 7(7), 163; https://doi.org/10.3390/horticulturae7070163 - 28 Jun 2021

Cited by 49 | Viewed by 10093

Abstract

Transport duration affects the vibration level generated which has adverse effects on fresh produce during transportation. Furthermore, temperature affects the quality of fresh commodities during storage. This study evaluated physical changes in tomatoes during transportation and storage. Tomatoes were transported at three distances [...] Read more.

Transport duration affects the vibration level generated which has adverse effects on fresh produce during transportation. Furthermore, temperature affects the quality of fresh commodities during storage. This study evaluated physical changes in tomatoes during transportation and storage. Tomatoes were transported at three distances (100, 154, and 205 km) from a local farm and delivered to the Postharvest Laboratory where vibration acceleration was recorded per distance. Tomato was stored at two different temperatures (10 °C and 22 °C) for 12 days. The physical qualities like weight loss and firmness of all tomato samples were evaluated. RGB image acquisition system was used to assess the color change of tomato. The results of vibration showed that over 40% of accelerations occurred in the range of 0.82–1.31 cm/s² of all transport distances. Physical quality analyses like weight loss and firmness were highly affected by transportation distance, storage temperature, and storage period. The reduction in weight loss and firmness was the highest in tomatoes transported from the farthest distance and stored at 22 °C. Lightness, yellowness, and hue values showed a high reduction as transport distance increased particularly in tomatoes stored at 22 °C. Redness, total color difference, and color indices increased significantly on tomatoes transported from 205 km and stored at 10 °C and 22 °C. The study indicated that the increase in transportation distance and storage temperature cause higher changes in the physical qualities of tomatoes. Full article

(This article belongs to the Collection Postharvest Handling of Horticultural Crops)

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18 pages, 1552 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

First Steps toward a Test Procedure to Identify Peat Substitutes for Growing Media by Means of Chemical, Physical, and Biological Material Characteristics

by Katharina Leiber-Sauheitl, Heike Bohne and Jürgen Böttcher

Horticulturae 2021, 7(7), 164; https://doi.org/10.3390/horticulturae7070164 - 28 Jun 2021

Cited by 11 | Viewed by 2352

Abstract

Due to the major environmental impact of peat-based growing media production and the need of lowering greenhouse gas emissions in all sectors, a wider application of peat substitutes in growing media is requested. All peat substitutes under use have constraints associated with their [...] Read more.

Due to the major environmental impact of peat-based growing media production and the need of lowering greenhouse gas emissions in all sectors, a wider application of peat substitutes in growing media is requested. All peat substitutes under use have constraints associated with their properties. Therefore, a preliminary test procedure for identifying new raw materials as peat substitutes in growing media was developed and validated. By applying the preliminary test procedure, the potential limitations of cultivation of potential peat substitutes are indicated, and measures for cultivation regulation are recommended. For the development of the new preliminary test procedure, four raw materials were investigated: composted heather, alder, cattail, and reed. The preliminary test procedure comprises several material and technological criteria as well as aspects of plant cultivation, enabling the evaluation of the raw materials and the processed components for growing media. Results derived from the preliminary test procedure were checked and confirmed by experiments with horticultural crops in different sections of commercial horticulture. Within two years, the identification of new peat substitutes was possible by the application of the preliminary test procedure and its test criteria, which provide a structure for the systematic investigation of potential new peat substitutes starting with the raw material. Full article

(This article belongs to the Special Issue Optimising Soilless Culture Systems and Alternative Growing Media to Current Used Materials)

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14 pages, 1096 KiB

Open AccessEditor’s ChoiceArticle

Effects of Water Stress on the Phenolic Compounds of ‘Merlot’ Grapes in a Semi-Arid Mediterranean Climate

by Juan L. Chacón-Vozmediano, Jesús Martínez-Gascueña, Esteban García-Romero, Sergio Gómez-Alonso, Francisco J. García-Navarro and Raimundo Jiménez-Ballesta

Horticulturae 2021, 7(7), 161; https://doi.org/10.3390/horticulturae7070161 - 22 Jun 2021

Cited by 9 | Viewed by 2101

Abstract

Of all the abiotic stress types to which plants grown in fields are exposed, the most influential is water stress. It is well accepted that adopting controlled deficit irrigation strategies during the growing season has beneficial effects on the chemical compositions of grapes [...] Read more.

Of all the abiotic stress types to which plants grown in fields are exposed, the most influential is water stress. It is well accepted that adopting controlled deficit irrigation strategies during the growing season has beneficial effects on the chemical compositions of grapes and red wines. However, there is a discrepancy in the timing, intensity and duration of deficit. This study aimed to evaluate the changes in phenolic composition of ‘merlot’ cultivar grapes when subjected to different levels of water stress in a semi-arid Mediterranean climate. Four treatments with different water stress levels were applied within two phenological intervals (flowering-veraison, veraison-maturity) to 128 grapevines for two consecutive years. The water stress levels for Treatments 1, 2, 3 and 4 were: no-light, light-moderate, moderate-intense and intense for the flowering-veraison and veraison-maturity intervals, respectively. Water stress distinctly affected the phenolic compounds in skin and seeds. The concentrations of flavan-3-ols and total polyphenols were much higher in seeds than in skin, and in both fractions, tannins are the major compounds. Full article

(This article belongs to the Special Issue Grape Responses to Abiotic and Biotic Stresses)

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17 pages, 1397 KiB

Open AccessEditor’s ChoiceArticle

Does Participation in Agricultural Value Chain Activities Influence Smallholder Fruit Grower Production Performance? A Cross-Sectional Study of Apple Farmers in Shandong, China

by Xiaolei Wang, Apurbo Sarkar, Hongyu Wang and Fuhong Zhang

Horticulturae 2021, 7(6), 153; https://doi.org/10.3390/horticulturae7060153 - 15 Jun 2021

Cited by 8 | Viewed by 3301

Abstract

The value chain comprises several factors and activities useful for strengthening production and distribution by connecting producers with suppliers, intermediaries, and marketplaces and collaboratively creating added value for products or goods. However, the values of agricultural products mostly depend on various factors and [...] Read more.

The value chain comprises several factors and activities useful for strengthening production and distribution by connecting producers with suppliers, intermediaries, and marketplaces and collaboratively creating added value for products or goods. However, the values of agricultural products mostly depend on various factors and actors, which should be linked together for fostering added values. Thus, there may be strong ground for facilitating a smooth transition of the agricultural value chain (AVC) within the prospects of emerging countries. It could be a key means of promoting a profound connection between smallholder farmers and modern agriculture facilities. It could be especially crucial for the highly perishable and high-value product such as fruits. The main aims of the study are to evaluate the factors influencing smallholder apple farmers’ participation in the agricultural value chain and determine whether participation in AVC improves farmers’ production performance. The empirical setup of the study was chosen based on survey data of apple growers in Shandong, China. The propensity score matching (PSM) and inverse probability weighted regression adjustment (IPWRA) models were employed to craft the study’s outcomes. The main conclusions are as follows. (1) Fruit farmers’ gender, total household expenditure, housing value, planting scale, planting years, degree of specialization, days of family labour input, and total days of employment have significant effects on their participation in AVC activities. (2) Fruit farmers’ usage of improved fertilizers and organization participation supports a higher yield and net income per acre. (3) Participating in two kinds of AVC can significantly improve the yield per acre and net income per acre compared with only using one type of AVC (improved fertilizer). Policy makers should improve the existing policy by eliminating institutional barriers and enhancing human factors for farmers to participate in high-value chain activities. Governments should extend technical support, and enhance training facilities, and comprehensively promote the AVC among smallholder farmers. Finally, farmers’ organizations (e.g., cooperatives and credit organizations) should come forward to help facilitate the effectiveness of AVC. Full article

(This article belongs to the Special Issue Reducing Food Loss: Postharvest Handling Technologies and Systems Supporting Smallholder Farmers)

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13 pages, 1555 KiB

Open AccessEditor’s ChoiceArticle

Long-Term Irrigation with Treated Municipal Wastewater from the Wadi-Musa Region: Soil Heavy Metal Accumulation, Uptake and Partitioning in Olive Trees

by Khaled A. Al-Habahbeh, Mohamed B. Al-Nawaiseh, Rabea S. Al-Sayaydeh, Jehad S. Al-Hawadi, Randa N. Albdaiwi, Hmoud S. Al-Debei and Jamal Y. Ayad

Horticulturae 2021, 7(6), 152; https://doi.org/10.3390/horticulturae7060152 - 13 Jun 2021

Cited by 16 | Viewed by 3374

Abstract

Utilization of treated wastewater (TWW) for agricultural purposes has grown over the past few years because of limited available water resources. This study was performed to assess the long-term irrigation of treated wastewater from the Wadi-Musa region on the accumulation of heavy metals [...] Read more.

Utilization of treated wastewater (TWW) for agricultural purposes has grown over the past few years because of limited available water resources. This study was performed to assess the long-term irrigation of treated wastewater from the Wadi-Musa region on the accumulation of heavy metals in soil and their uptake and translocation to various parts of olive trees. Fifteen year old trees that had been grown and irrigated with treated wastewater resources since their establishment were used in this study. Irrigation water, soil, and plant samples (root, stem bark, leaves, fruits) were collected and chemically analyzed for their heavy metal content. Accumulation of heavy metals in irrigation water and soil were found to be within the acceptable range for the safe use of treated wastewater according to the standards of the WHO. However, long-term and continuous irrigation with TWW resulted in significant accumulation of heavy metals in plant parts when compared to their levels in irrigation water and soil. Uptake of metals was consistent among plant parts with the highest concentrations for Fe, Mn, Pb and Zn, and the lowest concentrations for Ni, Cr and Cd. Assessment of the bioaccumulation factor (BFC) and translocation factors (TF) of heavy metals into different plant parts indicated selective absorption and partitioning of these heavy metals into different plant parts. High BCF values were observed for Fe, Cu and Ni in roots and fruits, and Fe, Mn, Cd and Pb in leaves. Translocation factors of metal ions were variable among plant parts. Fruits had the highest TF for Cu, Cd and Zn metals, and the lowest for Mn and Fe, while leaves have the highest TF for Fe, Zn and Mn and the lowest for Cd and Pb. The results of this study indicate that olive trees are heavy metal accumulators, caution should be considered in long-term use of TWW and periodic assessment of possible hazards, especially on fruits and oil quality is required. Full article

(This article belongs to the Section Biotic and Abiotic Stress)

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13 pages, 2154 KiB

Open AccessEditor’s ChoiceArticle

Remobilization of Storage Nitrogen in Young Pear Trees Grafted onto Vigorous Rootstocks (Pyrus betulifolia)

by Yang Wu, Mingde Sun, Yuanyong Qi and Songzhong Liu

Horticulturae 2021, 7(6), 148; https://doi.org/10.3390/horticulturae7060148 - 10 Jun 2021

Cited by 3 | Viewed by 2366

Abstract

The remobilization of storage nitrogen (N) is affected by growth characteristics of young pear trees. Aboveground parts of young pear trees grafted on P. betulifolia grew more vigorously than that on dwarfing rootstocks. Therefore, the remobilization of storage N within young pear trees [...] Read more.

The remobilization of storage nitrogen (N) is affected by growth characteristics of young pear trees. Aboveground parts of young pear trees grafted on P. betulifolia grew more vigorously than that on dwarfing rootstocks. Therefore, the remobilization of storage N within young pear trees on vigorous rootstocks may be different from that on dwarfing rootstocks. A ¹⁵N tracing experiment, including six groups of one-year-old pear trees grafted on vigorous rootstocks in 2016, was conducted to investigate the mobilization of storage N from 2016 to 2018. Results indicated that about 44%, 31.4% and 24.6% of storage N remobilized in new growth was derived from the trunk, shoots and roots, respectively. Most of storage N remobilized in new organs were supplied by trunks and shoots. About 82.2% of storage N withdrawn from senescent leaves were recovered in the trunk and shoots during autumn. The aboveground parts played a more important role than roots in the cycling process of storage N in young pear trees. However, as compared with young pear trees on dwarfing rootstocks, more storage N recovered in new organs were supplied by roots of that on vigorous rootstocks, due to vigorous growth and more nutrient requirement of aboveground parts. Full article

(This article belongs to the Section Plant Nutrition)

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16 pages, 11547 KiB

Open AccessEditor’s ChoiceArticle

Synergistic Effect of Preharvest Spray Application of Natural Elicitors on Storage Life and Bioactive Compounds of Date Palm (Phoenix dactylifera L., cv. Khesab)

by Zienab F. R. Ahmed, Shamsa S. N. A. Alblooshi, Navjot Kaur, Sajid Maqsood and Guillermo Schmeda-Hirschmann

Horticulturae 2021, 7(6), 145; https://doi.org/10.3390/horticulturae7060145 - 10 Jun 2021

Cited by 26 | Viewed by 3340

Abstract

Despite the immense capabilities of the date palm, maintaining the fruit’s quality, marketability, and shelf life is still a challenge. This study aimed to assess the synergistic effect of a preharvest spray application of a natural elicitor chitosan, (Ch) 1% alone and in [...] Read more.

Despite the immense capabilities of the date palm, maintaining the fruit’s quality, marketability, and shelf life is still a challenge. This study aimed to assess the synergistic effect of a preharvest spray application of a natural elicitor chitosan, (Ch) 1% alone and in combination with salicylic acid (SA) 2 mM and calcium chloride (Ca) 3%; (Ch,SA, Ca,Ch+Ca, Ch+SA, Ch+SA+Ca), on the quality parameters, storage life, and bioactive compounds content of date fruit from ‘Khasab’ cultivar during cold storage for 60 days. The obtained results revealed that all treatments significantly retard senescence/decay of the fruit compared to the control. Ch+SA treated fruit followed by Ch, and Ch+SA+Ca had the lowest weight loss, color change, and the least decay after 60 days of storage. Ch+Ca, SA, Ca treated fruit had significantly lower levels of total soluble solids and highest total phenolic, tannins, and flavonoids contents compared to the control fruit. Antioxidant activities were found in all treatments, with significantly higher effect in Ch+SA+Ca and Ch+SA compared to the control. Our results provide an evidence for a synergistic effect of elicitors combination to extend the shelf life of date fruit during cold storage by preserving its quality and decreasing senescence/decay and recommend it as a promising strategy. Full article

(This article belongs to the Special Issue Propagation and Post-harvest of Fruit Crops)

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14 pages, 1738 KiB

Open AccessEditor’s ChoiceArticle

Effect of Daily Light Integral on Cucumber Plug Seedlings in Artificial Light Plant Factory

by Jiawei Cui, Shiwei Song, Jizhu Yu and Houcheng Liu

Horticulturae 2021, 7(6), 139; https://doi.org/10.3390/horticulturae7060139 - 7 Jun 2021

Cited by 17 | Viewed by 3445

Abstract

In a controlled environment, in an artificial light plant factory during early spring or midsummer, vegetable seedlings can be uniform, compact, and high quality. Appropriate light parameters can speed up the growth of seedlings and save on production costs. Two experiments were carried [...] Read more.

In a controlled environment, in an artificial light plant factory during early spring or midsummer, vegetable seedlings can be uniform, compact, and high quality. Appropriate light parameters can speed up the growth of seedlings and save on production costs. Two experiments were carried out in this study: (1) cucumber seedling growth under different daily light integrals (DLIs) (5.41–11.26 mol·m⁻²·d⁻¹) and optimum DLI for seedling production were explored (experiment 1: Exp. 1); (2) under the same DLI selected by Exp. 1, the effects of different light intensities and photoperiods on cucumber seedlings were investigated (experiment 2: Exp. 2). The root biomass, root-to-shoot ratio, seedling index, and shoot dry matter rate increased as the DLI increased from 5.41 to 11.26 mol·m⁻²·d⁻¹, while the shoot biomass and leaf area decreased in Exp. 1. The cucumber seedlings became more compact as DLI increased, but more flowers developed after transplanting when the DLI was 6.35 mol·m⁻²·d⁻¹. Under the optimal DLI (6.35 mol·m⁻²·d⁻¹), the optimal intensity was 110–125 μmol·m⁻²·s⁻¹, and the optimal photoperiod was 14–16 h, in which plant biomass, shoot dry matter rate, seedling index, and photochemical efficiency were higher. Full article

(This article belongs to the Special Issue Greenhouse Management for Better Vegetable Quality, Higher Nutrient Use Efficiency and Healthier Soil)

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16 pages, 1670 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

An Early Calcium Loading during Cherry Tree Dormancy Improves Fruit Quality Features at Harvest

by Michail Michailidis, Chrysanthi Polychroniadou, Maria-Anastasia Kosmidou, Dafni Petraki-Katsoulaki, Evangelos Karagiannis, Athanassios Molassiotis and Georgia Tanou

Horticulturae 2021, 7(6), 135; https://doi.org/10.3390/horticulturae7060135 - 6 Jun 2021

Cited by 10 | Viewed by 3853

Abstract

The possible role of an early calcium application via sprays (0.25, 0.5 and 1M CaCl₂) on dormant buds to improve sweet cherry (cv. Ferrovia) fruit quality at harvest was investigated. Fruit quality characteristics were also investigated in response to the age [...] Read more.

The possible role of an early calcium application via sprays (0.25, 0.5 and 1M CaCl₂) on dormant buds to improve sweet cherry (cv. Ferrovia) fruit quality at harvest was investigated. Fruit quality characteristics were also investigated in response to the age of spurs, the ripening stage, and their interactions. Results indicate that calcium enters the dormant flower buds and the phloem but not to the dormant vegetative buds. At harvest, the levels of Zn, Mn, and Cu were declined in fruits by increasing CaCl₂ doses of sprays. Fruit respiratory activity was higher and on–tree fruit cracking was lower in red-colour (unripe) cherries as well as in fruit that was produced by 2-year-old short spurs or by Ca-treated buds. Differences in the sweet cherry skin metabolic profiles were identified. Fruit produced from Ca-exposed spurs exhibited lower levels of ribose and other cell-wall-related sugars and higher sucrose, maltose, and quininic acid levels. Nutrient shift was increased in red cherries, while anthocyanins were boosted in the black ones. PCA analysis was performed between the high dose of calcium spray and a control for mineral element content and cherry quality traits. This study illustrates that the high dose of calcium application during bud dormancy can effectively improve sweet cherry fruit characteristics, in terms of calcium content, cracking incidence, and fruit set. Overall, the present study contributes to a better understanding of the impact of calcium nutrition in fruit crops, which will provide references for alternative nutrient management and quality control in sweet cherry production. Full article

(This article belongs to the Special Issue Improving Quality of Fruit)

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14 pages, 5306 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Is There Daily Growth Hysteresis versus Vapor Pressure Deficit in Cherry Fruit?

by Matteo Zucchini, Arash Khosravi, Veronica Giorgi, Adriano Mancini and Davide Neri

Horticulturae 2021, 7(6), 131; https://doi.org/10.3390/horticulturae7060131 - 3 Jun 2021

Cited by 5 | Viewed by 2309

Abstract

The growth of cherry fruit is generally described using a double sigmoid model, divided into four growth stages. Abiotic factors are considered to be significant components in modifying fruit growth, and among these, the vapor pressure deficit (VPD) is deemed the most effective. [...] Read more.

The growth of cherry fruit is generally described using a double sigmoid model, divided into four growth stages. Abiotic factors are considered to be significant components in modifying fruit growth, and among these, the vapor pressure deficit (VPD) is deemed the most effective. In this study, we investigated sweet cherry fruit growth through the continuous, hourly monitoring of fruit transversal diameter over two consecutive years (2019 and 2020), from the beginning of the third stage to maturation (forth stage). Extensometers were used in the field and VPD was calculated from weather data. The fruit growth pattern up to the end of the third stage demonstrated three critical steps during non-rainy days: shrinkage, stabilization and expansion. In the third stage of fruit growth, a partial clockwise hysteresis curve of circadian growth, as a response to VPD, appeared on random days. The pattern of fruit growth during rainy days was not distinctive, but the amount and duration of rain caused a consequent decrease in the VPD and indirectly boosted fruit growth. At the beginning of the fourth stage, the circadian growth changed and the daily transversal diameter vs VPD formed fully clockwise hysteresis curves for most of this stage. Our findings indicate that hysteresis can be employed to evaluate the initial phenological phase of fruit maturation, as a fully clockwise hysteresis curve was observable only in the fourth stage of fruit growth. There are additional opportunities for its use in the management of fruit production, such as in precision fruit farming. Full article

(This article belongs to the Special Issue Feature Papers in Horticulturae Ⅱ)

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16 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Coir, an Alternative to Peat—Effects on Plant Growth, Phytochemical Accumulation, and Antioxidant Power of Spinach

by Rui M. A. Machado, Isabel Alves-Pereira, Rui Ferreira and Nazim S. Gruda

Horticulturae 2021, 7(6), 127; https://doi.org/10.3390/horticulturae7060127 - 28 May 2021

Cited by 17 | Viewed by 4063

Abstract

The effects of four commercial substrates, a peat-based substrate, and three coir types (coir pith, coir chips, and coir pith + fibers) on yield, phytochemical accumulation, and antioxidant activity were evaluated in Spinacia oleracea L. cv. ‘Manatee’. Soil-blocked spinach seedlings were transplanted into [...] Read more.

The effects of four commercial substrates, a peat-based substrate, and three coir types (coir pith, coir chips, and coir pith + fibers) on yield, phytochemical accumulation, and antioxidant activity were evaluated in Spinacia oleracea L. cv. ‘Manatee’. Soil-blocked spinach seedlings were transplanted into Styrofoam planting boxes filled with the substrate. Each planting box was irrigated daily by drip with a complete nutrient solution, and the irrigation scheduling was optimized to the peat. Leaf area and fresh yield in coir pith and coir pith + fiber were similar to those obtained in peat. However, shoot dry weight accumulation and leaf chlorophyll were lower in plants grown in coir. Substrate type did not affect leaf carotenoids. Total flavonoid content was higher in plants grown in the different types of coir. Total phenols and antioxidant activity (DPPH) were higher in plants grown in coir pith. This indicates that the different coir types, mainly coir pith, may provide an alternative to peat since they allowed a high fresh yield to be reached and the total flavonoids to be increased. In contrast, the levels of other phytochemicals and antioxidant activity were usual for spinach. However, further research is necessary to analyze the effects of irrigation scheduling and the nutrient solution adjusted to each growing medium on yield and phytochemical accumulation. Full article

(This article belongs to the Special Issue Optimising Soilless Culture Systems and Alternative Growing Media to Current Used Materials)

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15 pages, 2827 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Transcriptome Co-Expression Network Analysis Identifies Key Genes and Regulators of Sweet Cherry Anthocyanin Biosynthesis

by Haiying Yang, Changping Tian, Xiwen Li, Hansheng Gong and Aidi Zhang

Horticulturae 2021, 7(6), 123; https://doi.org/10.3390/horticulturae7060123 - 24 May 2021

Cited by 11 | Viewed by 2685

Abstract

Anthocyanin is the key factor that results in the attractive color of sweet cherry fruits. However, information regarding sweet cherry coloration and the potential mechanisms underlying anthocyanin biosynthesis is limited. In this study, we found that the anthocyanin accumulation varied in sweet cherry [...] Read more.

Anthocyanin is the key factor that results in the attractive color of sweet cherry fruits. However, information regarding sweet cherry coloration and the potential mechanisms underlying anthocyanin biosynthesis is limited. In this study, we found that the anthocyanin accumulation varied in sweet cherry flesh and peel, while the anthocyanin content increased sharply in the dark red (DR) stage. Correlations between anthocyanin concentrations and RNA sequencing (RNA-seq), constructed with Weighted Gene Co-Expression Network Analysis (WGCNA), indicated that two structural genes (Pac4CL2, PacANS) and 11 transcription factors (PacbHLH13/74, PacDIV, PacERF109/115, PacGATA8, PacGT2, PacGTE10, PacMYB308, PacPosF21, and PacWRKY7) had similar expression patterns with the changes in anthocyanin content. Additionally, real-time PCR verified all of these gene expression patterns and revealed that PacANS exhibited the highest transcription level. In order to search for potential regulators for anthocyanin biosynthesis, a dual-luciferase assay was performed to investigate the regulatory activities of 11 transcription factors on the PacANS promoter. The results revealed that two novelty bHLHs, PacbHLH13 and PacbHLH74, can trans-activate the PacANS promoter and they might be the candidate genes for regulating anthocyanin synthesis in sweet cherry fruits. The present findings provide a novel viewpoint with regard to anthocyanin biosynthesis mechanisms and the regulatory transcriptional network of fruit coloration in sweet cherries. Full article

(This article belongs to the Collection Advances in Fruit Quality Formation and Regulation)

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4 pages, 177 KiB

Open AccessEditor’s ChoiceEditorial

Special Issue: Feature Papers 2020

by Douglas D. Archbold

Horticulturae 2021, 7(6), 121; https://doi.org/10.3390/horticulturae7060121 - 21 May 2021

Cited by 1 | Viewed by 1598

Abstract

The goal of this Special Issue is to highlight, through selected works, frontier research in basic to applied horticulture among those published in Horticulturae in 2020 [...] Full article

(This article belongs to the Special Issue Feature Papers in Horticulturae)

10 pages, 257 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Evaluation of the Microbiological Quality of Fresh Cilantro, Green Onions, and Hot Peppers from Different Types of Markets in Three U.S. States

by Yi Su, Wei-Yea Hsu, Tung-Shi Huang and Amarat Simonne

Horticulturae 2021, 7(6), 122; https://doi.org/10.3390/horticulturae7060122 - 21 May 2021

Cited by 4 | Viewed by 2194

Abstract

The consumption of fresh produce and use of fresh herbs as flavoring agents in range of culinary preparation has increased in recent years due to consumer demand for a healthier lifestyle. Consumer preference for farmers’ markets and locally owned grocery stores have also [...] Read more.

The consumption of fresh produce and use of fresh herbs as flavoring agents in range of culinary preparation has increased in recent years due to consumer demand for a healthier lifestyle. Consumer preference for farmers’ markets and locally owned grocery stores have also grown in the U.S. in recent years. Most consumers perceive locally available produce to be a safer choice, but limited data is available. We evaluated microbiological quality, including aerobic plate count (APC), generic E. coli and total coliforms (TC), and human pathogens (Salmonella spp., E. coli O157: H7, and Shigella sonnei/Shigella spp.), of cilantro (n = 132), green onions (n = 131), jalapeño peppers (n = 129) and serrano peppers (n = 126) purchased from national chains, farmers’ markets and locally owned grocery stores in seven cities of the U.S. Of the 518 samples, enumerable populations of E. coli were found in one cilantro sample and three jalapeño samples, ranging from 1.18 to 2.42 log₁₀ CFU/g. APC and TC ranged from 3.84 to 9.27 log₁₀ CFU/g and from 0.84 to 5.84 log₁₀ CFU/g, respectively. Overall, the APC of produce samples from national chains was lower than that from farmers’ markets and locally owned grocery stores (p < 0.05). Cilantro had a significantly highest APC among tested produce types (p < 0.05). Risk factor analysis indicated that national chain had significant lower APC populations than farmer’s market or local markets (p < 0.05) and cilantro had higher APC populations than the other three types of produce (p < 0.05). Risk factor analysis also showed that TC populations in green onions were significantly higher than those in serrano peppers (p < 0.05). No human pathogens (Salmonella spp., E. coli O157: H7, or Shigella sonnei/Shigella spp.) were detected in any of the tested produce samples. The high prevalence of TC and high APC counts highlight the importance of consumer vigilance and practice in handling fresh produce that is often consumed raw or used to garnish dishes. Full article

(This article belongs to the Special Issue Production and Quality of Medicinal and Aromatic Plants)

21 pages, 7556 KiB

Open AccessEditor’s ChoiceArticle

CaHSP18.1a, a Small Heat Shock Protein from Pepper (Capsicum annuum L.), Positively Responds to Heat, Drought, and Salt Tolerance

by Yan-Li Liu, Shuai Liu, Jing-Jing Xiao, Guo-Xin Cheng, Haq Saeed ul and Zhen-Hui Gong

Horticulturae 2021, 7(5), 117; https://doi.org/10.3390/horticulturae7050117 - 18 May 2021

Cited by 8 | Viewed by 2562

Abstract

Pepper is a thermophilic crop, shallow-rooted plant that is often severely affected by abiotic stresses such as heat, salt, and drought. The growth and development of pepper is seriously affected by adverse stresses, resulting in decreases in the yield and quality of pepper [...] Read more.

Pepper is a thermophilic crop, shallow-rooted plant that is often severely affected by abiotic stresses such as heat, salt, and drought. The growth and development of pepper is seriously affected by adverse stresses, resulting in decreases in the yield and quality of pepper crops. Small heat shock proteins (s HSPs) play a crucial role in protecting plant cells against various stresses. A previous study in our laboratory showed that the expression level of CaHSP18.1a was highly induced by heat stress, but the function and mechanism of CaHSP18.1a responding to abiotic stresses is not clear. In this study, we first analyzed the expression of CaHSP18.1a in the thermo-sensitive B6 line and thermo-tolerant R9 line and demonstrated that the transcription of CaHSP18.1a was strongly induced by heat stress, salt, and drought stress in both R9 and B6, and that the response is more intense and earlier in the R9 line. In the R9 line, the silencing of CaHSP18.1a decreased resistance to heat, drought, and salt stresses. The silencing of CaHSP18.1a resulted in significant increases in relative electrolyte leakage (REL) and malonaldehyde (MDA) contents, while total chlorophyll content decreased under heat, salt, and drought stresses. Overexpression analyses of CaHSP18.1a in transgenic Arabidopsis further confirmed that CaHSP18.1a functions positively in resistance to heat, drought, and salt stresses. The transgenic Arabidopsis had higherchlorophyll content and activities of superoxide dismutase, catalase, and ascorbate peroxidase than the wild type (WT). However, the relative conductivity and MDA content were decreased in transgenic Arabidopsis compared to the wild type (WT). We further showed that the CaHSP18.1a protein is localized to the cell membrane. These results indicate CaHSP18.1a may act as a positive regulator of responses to abiotic stresses. Full article

(This article belongs to the Special Issue Advances in Molecular Breeding of Vegetable Crops)

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14 pages, 5081 KiB

Open AccessEditor’s ChoiceArticle

Plant Production and Leaf Anatomy of Mertensia maritima (L.) Gray: Comparison of In Vitro Culture Methods to Improve Acclimatization

by Andrea Copetta, Miriam Bazzicalupo, Arianna Cassetti, Ilaria Marchioni, Carlo Mascarello, Laura Cornara, Laura Pistelli and Barbara Ruffoni

Horticulturae 2021, 7(5), 111; https://doi.org/10.3390/horticulturae7050111 - 13 May 2021

Cited by 6 | Viewed by 3259

Abstract

Mertensia maritima is a commercially interesting herb with edible leaves and flowers, characterized by oyster flavor and taste. Plant propagation and traditional cultivation are challenging for this species. Therefore, the main purpose of the present study was to establish successful protocols aimed at [...] Read more.

Mertensia maritima is a commercially interesting herb with edible leaves and flowers, characterized by oyster flavor and taste. Plant propagation and traditional cultivation are challenging for this species. Therefore, the main purpose of the present study was to establish successful protocols aimed at ensuring oyster plant shoot propagation, rooting and in vivo acclimatization. Both micropropagation and rooting were tested, comparing the traditional in vitro solid substrate in jar vs. the liquid culture in a temporary immersion system (TIS) bioreactor (Plantform™). A Murashige and Skoog (MS) medium added with 4-μM thidiazuron (TDZ) and 1-μM α-naphthaleneacetic acid (NAA) was employed for micropropagation, while a half-strength MS medium supplemented with 4-μM indole−3-butyric acid (IBA) was used for rooting. Different acclimatization conditions in the greenhouse or in growth chamber were tested. Morphometric and microscopical analyses were performed on the oyster plant leaves at the propagation, rooting and acclimatization stages both in a jar and in a TIS. Micropropagation in a TIS allowed to obtain large shoots, while a great number of shoots was observed in the jar. M. maritima shoots rooted in TIS produced more developed roots, leaves with more developed waxy glands and well-formed stomata; moreover, the plants coming from the TIS showed the best acclimatization performances. Full article

(This article belongs to the Collection Application of Tissue Culture to Horticulture)

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11 pages, 1843 KiB

Open AccessEditor’s ChoiceArticle

Effects of Hydrogen Peroxide on Organically Fertilized Hydroponic Lettuce (Lactuca sativa L.)

by Vanessa Lau and Neil Mattson

Horticulturae 2021, 7(5), 106; https://doi.org/10.3390/horticulturae7050106 - 10 May 2021

Cited by 12 | Viewed by 5498

Abstract

Hydroponic production typically uses conventional fertilizers, but information is lacking on the use of organic hydroponic fertilizers. Development of microbial communities and biofilm that can reduce dissolved oxygen availability is a difficulty with organic hydroponics. One potential solution is the use of hydrogen [...] Read more.

Hydroponic production typically uses conventional fertilizers, but information is lacking on the use of organic hydroponic fertilizers. Development of microbial communities and biofilm that can reduce dissolved oxygen availability is a difficulty with organic hydroponics. One potential solution is the use of hydrogen peroxide (H₂O₂) which can reduce microbial populations and decompose to form oxygen. However, information is lacking on the impact of hydrogen peroxide on hydroponic crop performance. The aim of this study was to determine the effects of H₂O₂ concentrations in deep water culture hydroponics by assessing how it affects plant size and yield in lettuce (Lactuca sativa L.) “Rouxai”. In this experiment, three H₂O₂ treatments, namely the application of 0, 37.5 or 75 mg/L H₂O₂ to 4 L aerated hydroponic containers with either conventional or organic fertilizer, were compared. The containers had either fish-based organic fertilizer (4-4-1, N-P₂O₅-K₂O) or inorganic mineral based conventional nutrient solution (21-5-20, N-P₂O₅-K₂O), both applied at 150 mg/L N. Three replicates of each H₂O₂ treatment–fertilizer combination were prepared resulting in a total of eighteen mini hydroponic containers each with one head of lettuce. There were two growth cycles: fall 2018 and spring 2019. When added to conventional fertilizers, both 37.5 mg/L and 75 mg/L of H₂O₂ led to stunted growth or death of lettuce plants. However, when 37.5 mg/L of H₂O₂ was applied to organic fertilizers, the lettuce yield nearly matched that of the conventionally fertilized control, demonstrating that the application of H₂O₂ has the potential to make organic hydroponic fertilization a more viable method in the future. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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23 pages, 832 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Biochemical, Physiological, and Molecular Aspects of Ornamental Plants Adaptation to Deficit Irrigation

by Maria Giordano, Spyridon A. Petropoulos, Chiara Cirillo and Youssef Rouphael

Horticulturae 2021, 7(5), 107; https://doi.org/10.3390/horticulturae7050107 - 10 May 2021

Cited by 27 | Viewed by 5017

Abstract

There is increasing concern regarding global warming and its severe impact on the farming sector and food security. Incidences of extreme weather conditions are becoming more and more frequent, posing plants to stressful conditions, such as flooding, drought, heat, or frost etc. Especially [...] Read more.

There is increasing concern regarding global warming and its severe impact on the farming sector and food security. Incidences of extreme weather conditions are becoming more and more frequent, posing plants to stressful conditions, such as flooding, drought, heat, or frost etc. Especially for arid lands, there is a tug-of-war between keeping high crop yields and increasing water use efficiency of limited water resources. This difficult task can be achieved through the selection of tolerant water stress species or by increasing the tolerance of sensitive species. In this scenario, it is important to understand the response of plants to water stress. So far, the response of staple foods and vegetable crops to deficit irrigation is well studied. However, there is lack of literature regarding the responses of ornamental plants to water stress conditions. Considering the importance of this ever-growing sector for the agricultural sector, this review aims to reveal the defense mechanisms and the involved morpho-physiological, biochemical, and molecular changes in ornamental plant’s responses to deficit irrigation. Full article

(This article belongs to the Special Issue Drought Stress in Horticultural Plants)

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18 pages, 2237 KiB

Open AccessEditor’s ChoiceArticle

Genetic Diversity and Population Differentiation of Pinus koraiensis in China

by Xiang Li, Minghui Zhao, Yujin Xu, Yan Li, Mulualem Tigabu and Xiyang Zhao

Horticulturae 2021, 7(5), 104; https://doi.org/10.3390/horticulturae7050104 - 9 May 2021

Cited by 11 | Viewed by 3429

Abstract

Pinus koraiensis is a well-known precious tree species in East Asia with high economic, ornamental and ecological value. More than fifty percent of the P. koraiensis forests in the world are distributed in northeast China, a region with abundant germplasm resources. However, these [...] Read more.

Pinus koraiensis is a well-known precious tree species in East Asia with high economic, ornamental and ecological value. More than fifty percent of the P. koraiensis forests in the world are distributed in northeast China, a region with abundant germplasm resources. However, these natural P. koraiensis sources are in danger of genetic erosion caused by continuous climate changes, natural disturbances such as wildfire and frequent human activity. Little work has been conducted on the population genetic structure and genetic differentiation of P. koraiensis in China because of the lack of genetic information. In this study, 480 P. koraiensis individuals from 16 natural populations were sampled and genotyped. Fifteen polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers were used to evaluate genetic diversity, population structure and differentiation in P. koraiensis. Analysis of molecular variance (AMOVA) of the EST-SSR marker data showed that 33% of the total genetic variation was among populations and 67% was within populations. A high level of genetic diversity was found across the P. koraiensis populations, and the highest levels of genetic diversity were found in HH, ZH, LS and TL populations. Moreover, pairwise Fst values revealed significant genetic differentiation among populations (mean Fst = 0.177). According to the results of the STRUCTURE and Neighbor-joining (NJ) tree analyses and principal component analysis (PCA), the studied geographical populations cluster into two genetic clusters: cluster 1 from Xiaoxinganling Mountains and cluster 2 from Changbaishan Mountains. These results are consistent with the geographical distributions of the populations. The results provide new genetic information for future genome-wide association studies (GWAS), marker-assisted selection (MAS) and genomic selection (GS) in natural P. koraiensis breeding programs and can aid the development of conservation and management strategies for this valuable conifer species. Full article

(This article belongs to the Special Issue Neglected and Underutilized Plant Species in Horticultural and Ornamental Systems: Perspectives for Biodiversity, Nutraceuticals and Agricultural Sustainability)

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7 pages, 2485 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Artificial Intelligence and Novel Sensing Technologies for Assessing Downy Mildew in Grapevine

by Inés Hernández, Salvador Gutiérrez, Sara Ceballos, Rubén Iñíguez, Ignacio Barrio and Javier Tardaguila

Horticulturae 2021, 7(5), 103; https://doi.org/10.3390/horticulturae7050103 - 8 May 2021

Cited by 12 | Viewed by 3172

Abstract

Plant diseases and pests cause a large loss of world agricultural production. Downy mildew is a major disease in grapevine. Conventional techniques for plant diseases evaluations are time-consuming and require expert personnel. This work investigates novel sensing technologies and artificial intelligence applications for [...] Read more.

Plant diseases and pests cause a large loss of world agricultural production. Downy mildew is a major disease in grapevine. Conventional techniques for plant diseases evaluations are time-consuming and require expert personnel. This work investigates novel sensing technologies and artificial intelligence applications for assessing downy mildew in grapevine under laboratory conditions. In our methodology, machine vision is applied to assess downy mildew sporulation, while hyperspectral imaging is used to explore its potential capability towards early detection of this disease. Image analysis applied to RGB leaf disc images is used to estimate downy mildew (Plamopara viticola) severity in grapevine (Vitis vinifera L. cv Tempranillo). A determination coefficient (R²) of 0.76 ** and a root mean square error (RMSE) of 20.53% are observed in the correlation between downy mildew severity by computer vision and expert’s visual assessment. Furthermore, an accuracy of 81% is achieved to detect downy mildew early using hyperspectral images. These results indicate that non-invasive sensing technologies and computer vision can be applied for assessing and quantify sporulation of downy mildew in grapevine leaves. The severity of this key disease is evaluated in grapevine under laboratory conditions. In conclusion, computer vision, hyperspectral imaging and machine learning could be applied for important disease detection in grapevine. Full article

(This article belongs to the Special Issue Advances in Viticulture Production)

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18 pages, 5360 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Evaluation of Air Temperature, Photoperiod and Light Intensity Conditions to Produce Cucumber Scions and Rootstocks in a Plant Factory with Artificial Lighting

by Sewoong An, Hyunseung Hwang, Changhoo Chun, Yoonah Jang, Hee Ju Lee, Seung Hwang Wi, Kyung-Hwan Yeo, In-ho Yu and Yurina Kwack

Horticulturae 2021, 7(5), 102; https://doi.org/10.3390/horticulturae7050102 - 8 May 2021

Cited by 14 | Viewed by 3307

Abstract

Air temperature and light conditions are important factors not only to produce high-quality seedlings but also to promote energy efficiency in a plant factory with artificial lighting. In this study, we conducted two experiments in order to investigate the favorable conditions of air [...] Read more.

Air temperature and light conditions are important factors not only to produce high-quality seedlings but also to promote energy efficiency in a plant factory with artificial lighting. In this study, we conducted two experiments in order to investigate the favorable conditions of air temperature, light intensity and photoperiod for the production of cucumber scions and rootstocks in a plant factory with artificial lighting. Cucumber scions and rootstocks were cultivated in two combined treatments: the combination of three different levels of difference between the day and night temperature (DIF), 25/20, 26/18 and 27/16 °C and five different light intensity conditions of photosynthetic photon flux, 50, 100, 150, 200 and 250 μmol·m⁻²·s⁻¹ was set for the first experiment, and the combination of three different photoperiod conditions, 12, 16 and 20 h·d⁻¹ and five different light intensity conditions, 50, 100, 150, 200 and 250 μmol·m⁻²·s⁻¹ was set for the second experiment. In the air temperature and light intensity treatments, the hypocotyl elongation of cucumber scions and rootstocks was affected more largely by light intensity than DIF. The highest DIF treatment (27/16 °C) affected negatively on the accumulation of dry mass. On the contrary, the smallest DIF treatment (25/20 °C) was favorable for seedling growth due to lesser stress by rapid change of air temperature between photo- and dark-period. In the photoperiod and light intensity treatments, an increased DLI (daily light integral) promoted the growth of scions and rootstocks. Under the same DLI condition, the growth of scions and rootstocks increased with increasing photoperiod and decreasing light intensity. In both of experiments, while the dry weight increased with increasing the light intensity, the light use efficiencies were reduced by increasing the light intensity. Considering the growth and quality of seedlings and energy efficiency, the optimal environment conditions were represented by 25/20 °C of air temperature, 150 μmol·m⁻²·s⁻¹ of light intensity and 16 h·d⁻¹ of photoperiod. Full article

(This article belongs to the Special Issue Smart Farming Techniques for Protected Horticulture Facilities)

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18 pages, 2754 KiB

Open AccessEditor’s ChoiceArticle

Rootstock–Scion Hydraulic Balance Influenced Scion Vigor and Yield Efficiency of Malus domestica cv. Honeycrisp on Eight Rootstocks

by Hao Xu, Danielle Ediger, Amritpal Singh and Christopher Pagliocchini

Horticulturae 2021, 7(5), 99; https://doi.org/10.3390/horticulturae7050099 - 3 May 2021

Cited by 11 | Viewed by 3220

Abstract

Rootstocks with internal hydraulic limitations can effectively restrict scion growth, influence crop load, and improve yield efficiency in apple production. The characteristics of xylem vessels in rootstock and scion play essential roles in determining the hydraulic properties of the grafted tree; however, much [...] Read more.

Rootstocks with internal hydraulic limitations can effectively restrict scion growth, influence crop load, and improve yield efficiency in apple production. The characteristics of xylem vessels in rootstock and scion play essential roles in determining the hydraulic properties of the grafted tree; however, much remains unknown for commonly available rootstocks. In this study, we extracted secondary xylem using an increment borer from living Honeycrisp scion (Malus domestica cv. ‘Honeycrisp’), and two Malling rootstocks, one Budagovsky rootstock, and five Geneva rootstocks. The size and density of xylem vessels in rootstocks and scions were analyzed in relation to trunk cross-section area (TCSA), tree–water relations, and fruit dry matter of 2019, as well as with cumulative yield efficiency during 2014–2019. Honeycrisp scion exceeded most of the rootstocks in cross-section size and density of vessel elements. Scion vigor and cumulative yield were positively correlated with TCSA and total vessel cross-section area (VCSA) of the rootstock, with G.202 being the highest, and B.9 being the lowest with small xylem vessels in high density. In the rootstocks with the highest cumulative yield efficiency, the rootstock/scion ratio in VCSA was equal to or slightly higher than 1. Lower scion vessel density in G.214 was associated with lower fruit dry matter weight, more restricted water relations, and worsened leaf chlorosis. G.935 with larger rootstock vessels led to both high yield and high yield efficiency. This suggested that higher scion vessel density and larger rootstock vessel size can be advantageous characteristics for early-stage evaluation. Full article

(This article belongs to the Special Issue Rootstocks: History, Physiology, Management and Breeding)

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13 pages, 4412 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Quality Evaluation of Indoor-Grown Microgreens Cultivated on Three Different Substrates

by Roberta Bulgari, Marco Negri, Piero Santoro and Antonio Ferrante

Horticulturae 2021, 7(5), 96; https://doi.org/10.3390/horticulturae7050096 - 2 May 2021

Cited by 33 | Viewed by 7652

Abstract

The microgreens are innovative products in the horticultural sector. They are appreciated by consumers thanks to their novelty and health-related benefits, having a high antioxidant concentration. This produce can be adopted for indoor production using hydroponic systems. The aim of the present work [...] Read more.

The microgreens are innovative products in the horticultural sector. They are appreciated by consumers thanks to their novelty and health-related benefits, having a high antioxidant concentration. This produce can be adopted for indoor production using hydroponic systems. The aim of the present work was to investigate the influence of three growing media (vermiculite, coconut fiber, and jute fabric) on yield and quality parameters of two basil varieties (Green basil—Ocimum basilicum L., Red basil—Ocimum basilicum var. Purpurecsens) and rocket (Eruca sativa Mill.) as microgreens. Microgreens were grown in floating, in a Micro Experimental Growing (MEG^®) system equipped with LED lamps, with modulation of both energy and spectra of the light supplied to plants. Results showed high yield, comprised from 2 to 3 kg m⁻². Nutritional quality varied among species and higher antioxidant compounds were found in red basil on vermiculite and jute. Coconut fiber allowed the differentiation of crop performance in terms of sucrose and above all nitrate. In particular, our results point out that the choice of the substrate significantly affected the yield, the dry matter percentage and the nitrate concentration of microgreens, while the other qualitative parameters were most influenced by the species. Full article

(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)

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17 pages, 2810 KiB

Open AccessEditor’s ChoiceArticle

Generation of a High-Density Genetic Map of Pepper (Capsicum annuum L.) by SLAF-seq and QTL Analysis of Phytophthora capsici Resistance

by Yi-Fei Li, Shi-Cai Zhang, Xiao-Miao Yang, Chun-Ping Wang, Qi-Zhong Huang and Ren-Zhong Huang

Horticulturae 2021, 7(5), 92; https://doi.org/10.3390/horticulturae7050092 - 1 May 2021

Cited by 7 | Viewed by 3084

Abstract

Pepper (Capsicum annuum L.) is an economically significant global crop and condiment. Its yield can be severely reduced by the oomycete plant pathogen, Phytophthora capsici (P. capsici). Here, a high-density genetic map was created with a mapping panel of F [...] Read more.

Pepper (Capsicum annuum L.) is an economically significant global crop and condiment. Its yield can be severely reduced by the oomycete plant pathogen, Phytophthora capsici (P. capsici). Here, a high-density genetic map was created with a mapping panel of F₂ populations obtained from 150 individuals of parental lines PI201234 and 1287 and specific-locus amplified fragment sequencing (SLAF) that was then utilized to identify loci that are related to resistance to P. capsici. The sequencing depth of the genetic map was 108.74-fold for the male parent, 126.25-fold for the female parent, and 22.73-fold for the offspring. A high-resolution genetic map consisting of 5565 markers and 12 linkage groups was generated for pepper, covering 1535.69 cM and an average marker distance of 0.28 cM. One major quantitative trait locus (QTL) for the P. capsici resistance (CQPc5.1) was identified on Chr05 that explained the observed 11.758% phenotypic variance. A total of 23 candidate genes located within the QTL CQPc5.1 interval were identified, which included the candidate gene Capana05g000595 that encodes the RPP8-like protein as well as two candidate genes Capana05g000596 and Capana05g000597 that encodes a RPP13-like protein. Quantitative reverse-transcription PCR (qRT-PCR) revealed higher expression levels of Capana05g000595, Capana05g000596, and Capana05g000597 in P. capsici resistance accessions, suggesting their association with P. capsici resistance in pepper. Full article

(This article belongs to the Special Issue Advances in Molecular Breeding of Vegetable Crops)

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12 pages, 1544 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Spaceflight on Tomato Seed Quality and Biochemical Characteristics of Mature Plants

by Elena Dzhos, Nadezhda Golubkina, Marina Antoshkina, Irina Kondratyeva, Andrew Koshevarov, Anton Shkaplerov, Tatiana Zavarykina, Galina Nechitailo and Gianluca Caruso

Horticulturae 2021, 7(5), 89; https://doi.org/10.3390/horticulturae7050089 - 22 Apr 2021

Cited by 9 | Viewed by 2412

Abstract

Intensive space exploration includes profound investigations on the effect of weightlessness and cosmic radiation on plant growth and development. Tomato seeds are often used in such experiments though up to date the results have given rather vague information about biochemical changes in mature [...] Read more.

Intensive space exploration includes profound investigations on the effect of weightlessness and cosmic radiation on plant growth and development. Tomato seeds are often used in such experiments though up to date the results have given rather vague information about biochemical changes in mature plants grown from seeds subjected to spaceflight. The effect of half a year of storage in the International Space Station (ISS) on tomato seeds (cultivar Podmoskovny ranny) was studied by analyzing the biochemical characteristics and mineral content of mature plants grown from these seeds both in greenhouse and field conditions. A significant increase was recorded in ascorbic acid, polyphenol and carotenoid contents, and total antioxidant activity (AOA), with higher changes in the field conditions compared to greenhouse. Contrary to control plants, the ones derived from space-stored seeds demonstrated a significant decrease in root AOA. The latter plants also showed a higher yield, but lower content of fruit dry matter, sugars, total dissolved solids and organic acids. The fruits of plants derived from space-stored seeds demonstrated decreased levels of Fe, Cu and taste index. The described results reflect the existence of oxidative stress in mature tomato plants as a long-term consequence of the effect of spaceflight on seed quality, whereas the higher yield may be attributed to genetic modifications. Full article

(This article belongs to the Special Issue Nutritive Value, Polyphenolic Content, and Bioactive Constitution of Green, Red and Flowering Plants)

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10 pages, 2188 KiB

Open AccessEditor’s ChoiceArticle

A Quantitative Management of Potassium Supply for Hydroponic Production of Low-Potassium Cherry-Type Tomato Fruit for Chronic Kidney Disease Patients

by Satoru Tsukagoshi, Miho Aoki, Masahumi Johkan, Masaaki Hohjo and Toru Maruo

Horticulturae 2021, 7(4), 87; https://doi.org/10.3390/horticulturae7040087 - 19 Apr 2021

Cited by 3 | Viewed by 2912

Abstract

Chronic kidney disease (CKD) has been a global health problem in recent years. CKD patients often restrict their potassium (K) intake to avoid the high risk of hyperkalemia. In this study, quantitative K management in hydroponics was adopted to produce low K cherry-type [...] Read more.

Chronic kidney disease (CKD) has been a global health problem in recent years. CKD patients often restrict their potassium (K) intake to avoid the high risk of hyperkalemia. In this study, quantitative K management in hydroponics was adopted to produce low K cherry-type tomato (Solanum lycopersicom L.) fruit. The total quantity of K supply per plant during the cultivation was 7.2 g (1 K), 3.6 g (1/2 K), 1.8 g (1/4 K), 0.9 g (1/8 K) and 0.6 g (1/12 K), respectively. The total fruit yield decreased to about 75% at 1/2 K and 58% at 1/12 K compared to 1 K. The fruit K content was lower in 1/4 K, 1/8 K and 1/12 K than in 1 K and 1/2 K, and the fruit from 1/8 K and 1/12 K achieved below 100 mg 100 g⁻¹ FW of K. Total soluble solid content (Brix) was 7–8% in 1 K and 1/4 K but was lower in 1/8 K and 1/12 K. Fruit acid content decreased to 87% in 1/2 K to 70% in 1/4 K and 1/8 K, and to 57% in 1/12 K of 1 K. In conclusion, quantitative K management in hydroponics is expected to produce low K tomato fruit. Fruit K content of approximately 100 mg.100 g⁻¹ FW was achieved when the quantity of K supply was 1/4 K and 1/8 K, with a relatively smaller effect on fruit yield, Brix and acid content. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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14 pages, 4565 KiB

Open AccessEditor’s ChoiceArticle

A Transcriptomic Analysis of Gene Expression in Chieh-Qua in Response to Fusaric Acid Stress

by Min Wang, Wenrui Liu, Jinqiang Yan, Piaoyun Sun, Feng Chen, Biao Jiang, Dasen Xie, Yu’e Lin, Qingwu Peng and Xiaoming He

Horticulturae 2021, 7(4), 88; https://doi.org/10.3390/horticulturae7040088 - 19 Apr 2021

Cited by 2 | Viewed by 2433

Abstract

Fusarium wilt results in undesirable effects on the quality and production of chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How). Fusaric acid (FA), a secondary metabolite of biotin produced by pathogens of genus Fusarium, induced resistant responses in chieh-qua; however, the physiological and [...] Read more.

Fusarium wilt results in undesirable effects on the quality and production of chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How). Fusaric acid (FA), a secondary metabolite of biotin produced by pathogens of genus Fusarium, induced resistant responses in chieh-qua; however, the physiological and molecular mechanism(s) of FA resistance remains largely unknown. In our study, ‘A39’ (FA-resistant cultivar) exhibited decreased malondialdehyde (MDA) content and increased superoxide dismutase (SOD) enzyme activity when exposed to FA compared with ‘H5’ (FA-susceptible cultivar). More apoptosis cells existed in ‘H5’ than ‘A39’ after 2 days of FA treatment. RNA-seq results revealed that a total of 2968 and 3931 differentially expressed genes (DEGs) were detected under normal conditions (1562 up-regulated and 1406 down-regulated) and FA treatment (2243 up-regulated and 1688 down-regulated), respectively. Interestingly, DEGs associated with pathogen-related protein and ethylene (ET) biosynthesis and signal pathways were most significantly changed during FA stress. Notably, several crucial genes encoding pathogenesis-related protein (CL4451.Contig2, CL2175.Contig4), peroxidase (Unigene49615 and CL11695.Contig2), and ET-responsive transcription factors (TFs) (CL9320.Contig1, CL9849.Contig3, CL6826.Contig2, CL919. Contig6, and CL518.Contig7) were specifically induced after FA treatment. Collectively, the study provides molecular data for isolating candidate genes involved in FA resistance, especially ET related genes in chieh-qua. Full article

(This article belongs to the Special Issue Natural Actives Molecules: A Sustainable Solution to Fight against Diseases and Pests of Vegetable and Fruit Crops Ⅱ)

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13 pages, 2620 KiB

Open AccessEditor’s ChoiceArticle

Exogenous EBR Ameliorates Endogenous Hormone Contents in Tomato Species under Low-Temperature Stress

by Parviz Heidari, Mahdi Entazari, Amin Ebrahimi, Mostafa Ahmadizadeh, Alessandro Vannozzi, Fabio Palumbo and Gianni Barcaccia

Horticulturae 2021, 7(4), 84; https://doi.org/10.3390/horticulturae7040084 - 17 Apr 2021

Cited by 35 | Viewed by 3633

Abstract

Low-temperature stress is a type of abiotic stress that limits plant growth and production in both subtropical and tropical climate conditions. In the current study, the effects of 24-epi-brassinolide (EBR) as analogs of brassinosteroids (BRs) were investigated, in terms of hormone content, antioxidant [...] Read more.

Low-temperature stress is a type of abiotic stress that limits plant growth and production in both subtropical and tropical climate conditions. In the current study, the effects of 24-epi-brassinolide (EBR) as analogs of brassinosteroids (BRs) were investigated, in terms of hormone content, antioxidant enzyme activity, and transcription of several cold-responsive genes, under low-temperature stress (9 °C) in two different tomato species (cold-sensitive and cold-tolerant species). Results indicated that the treatment with exogenous EBR increases the content of gibberellic acid (GA3) and indole-3-acetic acid (IAA), whose accumulation is reduced by low temperatures in cold-sensitive species. Furthermore, the combination or contribution of BR and abscisic acid (ABA) as a synergetic interaction was recognized between BR and ABA in response to low temperatures. The content of malondialdehyde (MDA) and proline was significantly increased in both species, in response to low-temperature stress; however, EBR treatment did not affect the MDA and proline content. Moreover, in the present study, the effect of EBR application was different in the tomato species under low-temperature stress, which increased the catalase (CAT) activity in the cold-tolerant species and increased the glutathione peroxidase (GPX) activity in the cold-sensitive species. Furthermore, expression levels of cold-responsive genes were influenced by low-temperature stress and EBR treatment. Overall, our findings revealed that a low temperature causes oxidative stress while EBR treatment may decrease the reactive oxygen species (ROS) damage into increasing antioxidant enzymes, and improve the growth rate of the tomato by affecting auxin and gibberellin content. This study provides insight into the mechanism by which BRs regulate stress-dependent processes in tomatoes, and provides a theoretical basis for promoting cold resistance of the tomato. Full article

(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants)

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15 pages, 1033 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Peach, Apple, and Pear Fruit Quality: To Peel or Not to Peel?

by Michail Michailidis, Evangelos Karagiannis, Elpida Nasiopoulou, Christina Skodra, Athanassios Molassiotis and Georgia Tanou

Horticulturae 2021, 7(4), 85; https://doi.org/10.3390/horticulturae7040085 - 17 Apr 2021

Cited by 16 | Viewed by 4703

Abstract

The nutritional value of the peeled and unpeeled fruit (peel plus flesh tissues) was studied using four peach (Prunus persica L.; Red Heaven, Maria Blanca, Big Top, and Queen Giant), two pear (Pyrus communis L.; Santa Maria, Pyrus pyrifolia N.; Nashi), [...] Read more.

The nutritional value of the peeled and unpeeled fruit (peel plus flesh tissues) was studied using four peach (Prunus persica L.; Red Heaven, Maria Blanca, Big Top, and Queen Giant), two pear (Pyrus communis L.; Santa Maria, Pyrus pyrifolia N.; Nashi), and three apple (Malus domestica Borkh.; Gala, Granny Smith, and Red Chief) cultivars. Based on principal components analysis (PCA) models, there was a clear differentiation among the cultivars’ and the peeled fruits’ nutritional characteristics in comparison to the unpeeled ones. Increased antioxidant capacity and content of total phenols and flavonoids of peaches (Red Heaven and Maria Blanca) versus nectarines (Big Top and Queen Giant) were recorded. In contrast, nectarines were characterized by higher hydroxycinnamates and dry matter. The apples’ cultivar Granny Smith exhibited a high level of titratable acidity (TA), while the Gala displayed a high level of soluble solids concentration (SSC), carotenoids, dry matter, hydroxycinnamic acids, and flavonols at the unpeeled fruit, whereas the Red Chief by increased anthocyanins, antioxidant capacity, total phenols, and flavonoids. Nashi pears with peel were more beneficial due to the strong skin contribution in the fruits’ beneficial compounds content. The peel of the Granny Smith cultivar was associated with an increased level of P, K, Ca, and Mg, whereas that of Red Chief with increased anthocyanins and Mg content. Full article

(This article belongs to the Special Issue Improving Quality of Fruit)

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