Horticulturae

12 pages, 3507 KiB

Open AccessEditor’s ChoiceArticle

Lipidomics Analysis of Tea Leaves Cultured in Hydroponics Reveals That High Nitrogen Application Decreases Tea Plant Resistance to Ultraviolet Radiation

by Sijia Du, Meiya Liu, Fang Dong, Chuan Yue, Jianyun Ruan, Hongli Cao and Qunfeng Zhang

Horticulturae 2022, 8(8), 724; https://doi.org/10.3390/horticulturae8080724 - 11 Aug 2022

Cited by 1 | Viewed by 1654

Abstract

Lipid composition in tea leaves is significantly affected by ultraviolet (UV) radiation and nitrogen levels. Here, to reveal the response of lipids in tea plants (Camellia sinensis L.) to the interaction between nitrogen and UV radiation, we treated tea plants with three [...] Read more.

Lipid composition in tea leaves is significantly affected by ultraviolet (UV) radiation and nitrogen levels. Here, to reveal the response of lipids in tea plants (Camellia sinensis L.) to the interaction between nitrogen and UV radiation, we treated tea plants with three gradients of UV radiation under two nitrogen levels by the hydroponic method. Lipidomics results show that ultraviolet radiation can decrease neutral lipid (TAG) and increase membrane lipids (including PC, PE, and PG) under hydroponic conditions, indicating that tea plants could survive UV radiation by decomposing TAG to avoid damaging cells. In addition, the accumulation of phospholipids and galactolipids may be related to avoiding UV damage and enhancing photosynthesis in tea plants under UV radiation. Furthermore, the response of lipid components to UV radiation in tea plants under low nitrogen conditions is significantly lower than that under high nitrogen conditions, which suggests that excessive nitrogen application may reduce the resistance of tea plants to UV radiation. This study provides a theoretical basis for optimizing cultivation measures based on tea UV resistance. Full article

(This article belongs to the Special Issue Advances in Tea Plant Biology and Tea Quality Regulation)

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12 pages, 2339 KiB

Open AccessEditor’s ChoiceArticle

Effect of UV-B Irradiation on Bioactive Compounds of Red Perilla (Perilla frutescens (L.) Britton) Cultivated in a Plant Factory with Artificial Light

by Hideo Yoshida, Kanae Shimada, Shoko Hikosaka and Eiji Goto

Horticulturae 2022, 8(8), 725; https://doi.org/10.3390/horticulturae8080725 - 11 Aug 2022

Cited by 3 | Viewed by 1824

Abstract

In this study, we investigated the effect of UV-B irradiation 3 days prior to harvest, on the accumulation of rosmarinic acid (RA) and anthocyanin, and the expression of genes related to phenylpropanoid and flavonoid biosynthetic pathways, in red perilla (Perilla frutescens L.). [...] Read more.

In this study, we investigated the effect of UV-B irradiation 3 days prior to harvest, on the accumulation of rosmarinic acid (RA) and anthocyanin, and the expression of genes related to phenylpropanoid and flavonoid biosynthetic pathways, in red perilla (Perilla frutescens L.). In experiment 1, seedlings at 60 days after sowing (DAS) were subjected to UV-B irradiation at 0 (control), 6, and 10 W m⁻² under a 16 h light period; while in experiment 2, seedlings at 45 DAS were subjected to UV-B irradiation at 0 (control), 4 W m⁻² at continuous irradiation, and 6 W m⁻² at 16 h irradiation. UV irradiation of 10 W m⁻² for 16 h negatively affected leaf color, while irradiation at 6 W m⁻² enhanced RA biosynthesis and antioxidant capacity. Continuous UV-B irradiation of 4 W m⁻² increased the RA concentration by 92% compared to the control; however, this effect was smaller than that of UV-B irradiation at 6 W m⁻² for 16 h, 141% higher than that of the control and had a lower antioxidant capacity against UV-mediated ROS overproduction during the dark period. Results demonstrate that 6 W m⁻² of UV-B irradiation for 16 h is suitable for enhancing the RA concentration and content of red perilla. Full article

(This article belongs to the Special Issue Indoor Farming and Artificial Cultivation)

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23 pages, 7889 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Waterlogging Tolerance of Three Peach Rootstock Seedlings Based on Physiological, Anatomical and Ultra-Structural Changes

by Fangjie Xu, Huaqing Cai, Xianan Zhang, Mingshen Su, Huijuan Zhou, Xiongwei Li, Minghao Zhang, Yang Hu, Chao Gu, Jihong Du and Zhengwen Ye

Horticulturae 2022, 8(8), 720; https://doi.org/10.3390/horticulturae8080720 - 10 Aug 2022

Cited by 4 | Viewed by 2038

Abstract

Peach (Prunus persica (L.) Batsch) is a typical shallow-rooted fruit plant with a high respiratory intensity and oxygen demand, which makes it highly susceptible to oxygen-deficient soil conditions resulting from waterlogging. Rootstock waterlogging resistance is essential to the performance of cultivated peaches [...] Read more.

Peach (Prunus persica (L.) Batsch) is a typical shallow-rooted fruit plant with a high respiratory intensity and oxygen demand, which makes it highly susceptible to oxygen-deficient soil conditions resulting from waterlogging. Rootstock waterlogging resistance is essential to the performance of cultivated peaches under waterlogging stress. In comparison to Prunus persica var. persica (‘Maotao’, M) and Prunus davidiana (Carr.) C. de Vos (‘Shantao’, S), Prunus persica f. Hossu (‘Hossu’, H) exhibited superior leaf photosynthetic electron transfer efficiency, a higher rate of mycorrhizal fungi infection in both fine roots and mesophyll palisade cells, as well as earlier air cavity formation in both leaf midvein and fine roots under waterlogging stress. Furthermore, under non-waterlogging conditions, Hossu had greater leaf superoxide dismutase (SOD) activity, higher proline content, and a greater content of starch granules in the pith and xylem ray cells of stems and roots than rootstocks M and S. As a result, Hossu’s tolerance to waterlogging may be due to its higher photosynthetic efficiency, improved tissue oxygen permeability, higher energy metabolism, and increased intracellular mycorrhizal fungus infection rates in both root parenchyma cells and mesophyll palisade cells. Full article

(This article belongs to the Special Issue Advanced Studies in Fruit Trees under Water Stress)

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12 pages, 2534 KiB

Open AccessEditor’s ChoiceArticle

The Occurrence of Clubroot in Colombia and Its Relationship with Climate and Agronomic Practices

by Andrea Botero-Ramírez, Fabián Leonardo Padilla-Huertas, Stephen E. Strelkov and Celsa García-Dominguez

Horticulturae 2022, 8(8), 711; https://doi.org/10.3390/horticulturae8080711 - 8 Aug 2022

Cited by 1 | Viewed by 1493

Abstract

Clubroot, caused by Plasmodiophora brassicae, is a major disease of cruciferous crops in Colombia. Limited information is available, however, regarding its distribution or epidemiology in this country. The objectives of this study were to determine the occurrence of clubroot in the main [...] Read more.

Clubroot, caused by Plasmodiophora brassicae, is a major disease of cruciferous crops in Colombia. Limited information is available, however, regarding its distribution or epidemiology in this country. The objectives of this study were to determine the occurrence of clubroot in the main regions of Colombia where cruciferous crops are grown, and to examine the relationship between pathogen inoculum density and the likelihood of field infestation with crop management practices and climatic information. In total, 127 fields were surveyed across eight departments, the pathogen inoculum density was estimated, climatic information was obtained, and farmers were surveyed on their crop management practices. More than half (53.7%) of the fields visited were found to be clubroot-infested and pathogen DNA was detected in 91.3% of the surveyed fields. The only department where clubroot symptoms were not observed was Nariño. In infested fields, P. brassicae inoculum density varied between 3 × 10² and 1 × 10⁶ resting spores per gram of soil, with the highest inoculum density observed in Norte de Santander. All other departments had comparable spore loads. Inoculum density positively affected the likelihood of infestation of a field, and both spore loads and infestations were positively affected by the average temperature. Full article

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

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21 pages, 1980 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Nutrient Content with Different Fertilizer Management and Influence on Yield and Fruit Quality in Apple cv. Gala

by Mariana Mota, Maria João Martins, Gonçalo Policarpo, Layanne Sprey, Mafalda Pastaneira, Patrícia Almeida, Anabela Maurício, Cristina Rosa, João Faria, Miguel B. Martins, Miguel L. de Sousa, Ricardo Santos, Rui M. de Sousa, Anabela B. da Silva, Henrique Ribeiro and Cristina M. Oliveira

Horticulturae 2022, 8(8), 713; https://doi.org/10.3390/horticulturae8080713 - 8 Aug 2022

Cited by 10 | Viewed by 2716

Abstract

Assessing a plant’s nutritional status and fertilizer rates and types that can optimize fruit quality and yield are critical in intensive apple orchards. The aim of this work was to identify correlations between nutrients in the different organs that allow the early diagnosis [...] Read more.

Assessing a plant’s nutritional status and fertilizer rates and types that can optimize fruit quality and yield are critical in intensive apple orchards. The aim of this work was to identify correlations between nutrients in the different organs that allow the early diagnosis of the nutritional status and to assess the impact on the optimal nutrient content in apple leaves, as well as in the yield and quality of chemical and organic fertilization. Five orchards of ‘Gala’ were fertilized with different levels of NPK over a period of four years. Macro and micronutrients of buds, flowers, 45 and 90–110 days after full bloom (DAFB) leaves and 60 DAFB and 15 days before harvest (DBH) fruits were determined. Boron was the only element for which strong correlations, 0.7 < r < 0.9, were observed between all organ pairs. The fertilization treatments did not affect the nutrient concentrations in the leaves of 90–110 DAFB other than P, Ca and Mg and did not affect the macronutrients in the fruit. In one of the five orchards, the yield increased by 26% with double fertilization compared to standard fertilization and, for the other four orchards, the impact depended on the year. Fruit size was more related to crop load than to fertilization and TSS and firmness were not affected by the type or amount of fertilizers. Replacing part of the chemical fertilizer with organic materials did not affect productivity or fruit quality. Full article

(This article belongs to the Special Issue Strategies in Fruit Trees and Vegetables to Increase Nutrient Use Efficiency)

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14 pages, 1351 KiB

Open AccessEditor’s ChoiceArticle

Compost Composition and Application Rate Have a Greater Impact on Spinach Yield and Soil Fertility Benefits Than Feedstock Origin

by Alicia J. Kelley, David N. Campbell, Ann C. Wilkie and Gabriel Maltais-Landry

Horticulturae 2022, 8(8), 688; https://doi.org/10.3390/horticulturae8080688 - 29 Jul 2022

Cited by 7 | Viewed by 2222

Abstract

Rapid urbanization results in the accumulation of food wastes that can be composted and diverted from landfills. Previous lab incubations demonstrated that food-based composts can increase soil N relative to manure-based composts, but these benefits were not tested within a crop system. We [...] Read more.

Rapid urbanization results in the accumulation of food wastes that can be composted and diverted from landfills. Previous lab incubations demonstrated that food-based composts can increase soil N relative to manure-based composts, but these benefits were not tested within a crop system. We assessed soil fertility and yield of spinach (Spinacia oleracea L.) grown in two different soils in a greenhouse, comparing two food- and two manure-based composts added at the recommended N rate (101 kg N ha⁻¹). We quantified soil N mineralization and resin-extractable phosphorus, spinach biomass (root and shoot), and crop nutrient concentrations and accumulation. Nitrogen mineralization generally peaked four weeks after application, and one food-based compost (but no manure-based composts) increased soil phosphorus at harvest compared to an unamended control. One manure-based compost and one food-based compost produced a higher yield and greater nitrogen, phosphorus, and potassium accumulation than the unamended control, whereas only the food-based compost increased spinach phosphorus and potassium concentrations. There was a positive relationship between yield and compost inputs of potassium and plant-available nitrogen (especially nitrate), suggesting that potassium inputs may also explain differences observed among composts. Our results suggest that food-based compost provides more nutrients than composts made from cow manure fiber. Full article

(This article belongs to the Topic Soil Fertility and Plant Nutrition for Sustainable Agriculture)

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14 pages, 1274 KiB

Open AccessEditor’s ChoiceArticle

Onion Plant Size Measurements as Predictors for Onion Bulb Size

by Seyed Shahabeddin Nourbakhsh and Christopher S. Cramer

Horticulturae 2022, 8(8), 682; https://doi.org/10.3390/horticulturae8080682 - 27 Jul 2022

Cited by 3 | Viewed by 3943

Abstract

Onion is a biennial plant that produces a bulb. The larger the onion bulb, the more valuable it becomes. Therefore, it is important to study bulb weight and plant size components affecting it. For this study, four New Mexico State Univ. breeding lines [...] Read more.

Onion is a biennial plant that produces a bulb. The larger the onion bulb, the more valuable it becomes. Therefore, it is important to study bulb weight and plant size components affecting it. For this study, four New Mexico State Univ. breeding lines and two commercial cultivars, ‘Rumba’ and ‘Stockton Early Yellow’, were selected. These breeding lines and cultivars were evaluated for plant height, leaf number and sheath diameter, at five different dates two weeks apart throughout the growing season, and for bulb weight upon harvest. The experiment was designed as a randomized complete block design with three blocks each containing four replications. Plant size components were all positively correlated with each other and with bulb weight with correlation coefficients above 0.50. NMSU breeding lines also exhibited greater average bulb weights than commercial cultivars. Sheath diameter proved to be the best predictor of bulb size, showing strong positive correlations with bulb weight at around 12 weeks after transplanting, and positive correlations are observed as early as 6–8 weeks after transplanting. Full article

(This article belongs to the Special Issue Advances in Allium Breeding and Genetics)

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12 pages, 1084 KiB

Open AccessEditor’s ChoiceArticle

Effects of Supplemental UV-A LEDs on the Nutritional Quality of Lettuce: Accumulation of Protein and Other Essential Nutrients

by Myungjin Lee, Jungkwun Kim, Myung-Min Oh, Jin-Hui Lee and Channa B. Rajashekar

Horticulturae 2022, 8(8), 680; https://doi.org/10.3390/horticulturae8080680 - 26 Jul 2022

Cited by 6 | Viewed by 1724

Abstract

Light plays an important role in influencing the nutritional quality of food crops, especially with regard to the health-promoting phytochemicals. However, its role in affecting the nutritional quality with regard to the essential nutrients is not well understood. In this study, the effects [...] Read more.

Light plays an important role in influencing the nutritional quality of food crops, especially with regard to the health-promoting phytochemicals. However, its role in affecting the nutritional quality with regard to the essential nutrients is not well understood. In this study, the effects of preharvest UV-A treatment on the nutritional quality of lettuce (Lactuca sativa, cv. red-leaf ‘New Red Fire’ and green-leaf ‘Two Star’) in relation to the essential nutrients and health-promoting phytochemicals were explored. Lettuce plants were grown in a growth chamber and were subjected to supplemental UV-A LEDs (peak wavelength 375 nm) for a brief period (3–6 days) prior to harvest. UV-A LEDs were equipped with lenses to control the light dispersion. Many growth indices such as shoot fresh mass, leaf area, and leaf number were unaffected by supplemental UV-A in both varieties while shoot dry mass decreased in response to a 6-day UV-A treatment compared to the control. Leaf chlorophyll and carotenoid concentrations increased significantly in green-leaf lettuce after 3 or 6 days of UV-A treatment, but only after 3 days of UV-A treatment in red-leaf lettuce compared to the control. Leaf protein concentration increased significantly in both lettuce varieties along with a number of essential nutrients such as phosphorus, potassium, calcium, manganese, and sulfur in response to supplemental UV-A. Supplemental UV-A increased the accumulation of protein by approximately 48% in green-leaf lettuce and 31% in red-leaf lettuce compared to the control plants. Moreover, in addition to the above essential nutrients, green-leaf lettuce accumulated higher amounts of magnesium, copper, and zinc compared to the control plants, indicating that green-leaf lettuce was more responsive to preharvest supplemental UV-A treatment than red-leaf lettuce. However, the accumulation of total phenolic compounds and flavonoids in both varieties was lower under supplemental UV-A. Furthermore, the use of LED lenses did not have a consistent impact on most of the plant responses studied. Overall, the results indicate that a brief preharvest exposure of both red- and green-leaf lettuce varieties to UV-A increased their nutritional quality by enhancing the accumulation of protein and other major essential nutrients. Full article

(This article belongs to the Section Vegetable Production Systems)

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14 pages, 4602 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Maintaining Canopy Density under Summer Stress Conditions Retains PSII Efficiency and Modulates Must Quality in Cabernet Franc

by Michele Faralli, Roberto Zanzotti and Massimo Bertamini

Horticulturae 2022, 8(8), 679; https://doi.org/10.3390/horticulturae8080679 - 26 Jul 2022

Cited by 3 | Viewed by 1438

Abstract

Shoot topping and other summer grapevine management practices are considered crucial for producing high-quality wine. However, in recent years, climate change is increasing the need to reassess these strategies, as excessive radiation and high temperatures can negatively impact canopy functionality and berry quality. [...] Read more.

Shoot topping and other summer grapevine management practices are considered crucial for producing high-quality wine. However, in recent years, climate change is increasing the need to reassess these strategies, as excessive radiation and high temperatures can negatively impact canopy functionality and berry quality. Indeed, it has been hypothesized that limiting summer vegetative pruning may protect the bunch, via shading, and the leaf by maintaining a more favorable environment for leaf functionality (e.g., lower VPD, reduced high light stress) owing to a denser canopy. In this work, a series of canopy manipulation treatments (shoot topping vs. long-shoot bundling; secondary shoot trimming vs. untrimmed) were tested in a replicated factorial block design over two seasons in field-grown grapevine plants (cv. Cabernet Franc grafted in SO₄). Overall, treatments in which secondary shoot removal and/or shoot topping were not applied produced a higher canopy area, increased pruning wood and leaf layers, and had a higher F_v/F_m on warm days when compared to pruned canopies. These were associated with a year-dependent modulation of quality parameters of the must in which long-shoot bundling treatment, overall, produced the highest polyphenol and anthocyanin contents and must acidity. Our data provide evidence of a potential usefulness of preserving dense canopies under high temperature – high irradiance conditions with desirable effects on leaf photosynthesis and must quality when long-shoot bundling was applied. Full article

(This article belongs to the Section Viticulture)

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7 pages, 16456 KiB

Open AccessEditor’s ChoiceArticle

Pruning Quality Effects on Desiccation Cone Installation and Wood Necrotization in Three Grapevine Cultivars in France

by Emilie Bruez, Céline Cholet, Massimo Giudici, Marco Simonit, Tommasso Martignon, Mathilde Boisseau, Sandrine Weingartner, Xavier Poitou, Patrice Rey and Laurence Geny-Denis

Horticulturae 2022, 8(8), 681; https://doi.org/10.3390/horticulturae8080681 - 26 Jul 2022

Cited by 7 | Viewed by 1981

Abstract

Pruning experimental studies have been performed in different vineyards, in France, USA and Australia. This article investigates and models the effects of pruning quality on the installation of desiccation cones and wood necrotization. Two different modalities of pruning, short and high pruning, were [...] Read more.

Pruning experimental studies have been performed in different vineyards, in France, USA and Australia. This article investigates and models the effects of pruning quality on the installation of desiccation cones and wood necrotization. Two different modalities of pruning, short and high pruning, were performed at the same period each year on three cultivars in Bordeaux (Cabernet Sauvignon and Sauvignon Blanc) and Charente (Ugni Blanc) wine regions. In the short typ of pruning, the diaphragm was damaged but, in the high one, a 2–3 cm woody length was left immediately above the diaphragm. None of the three cultivars showed any correlation between necrosis length and spur diameter (R² < 0.1925). Analysis of the Ugni Blanc, 8 months after pruning, showed significantly more necrosis length (>60%) than either Cabernet Sauvignon (31–41%) or Sauvignon Blanc (25–55%). Desiccation cone necrotization rates also varied with the vintage, particularly for Ugni Blanc. 4 or 8 months after pruning, the newly-installed desiccation cones could then be analysed. High pruning stopped the desiccation cones at the diaphragm, which ensured that the sap flow path remained unaffected. Full article

(This article belongs to the Special Issue New Advances in Grapevine Trunk Diseases)

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28 pages, 5354 KiB

Open AccessEditor’s ChoiceReview

An Academic and Technical Overview on Plant Micropropagation Challenges

by Neama Abdalla, Hassan El-Ramady, Mayada K. Seliem, Mohammed E. El-Mahrouk, Naglaa Taha, Yousry Bayoumi, Tarek A. Shalaby and Judit Dobránszki

Horticulturae 2022, 8(8), 677; https://doi.org/10.3390/horticulturae8080677 - 25 Jul 2022

Cited by 30 | Viewed by 15648

Abstract

The production of micropropagated plants in plant-tissue-culture laboratories and nurseries is the most important method for propagation of many economic plants. Micropropagation based on tissue-culture technology involves large-scale propagation, as it allows multiplication of a huge number of true-to-type propagules in a very [...] Read more.

The production of micropropagated plants in plant-tissue-culture laboratories and nurseries is the most important method for propagation of many economic plants. Micropropagation based on tissue-culture technology involves large-scale propagation, as it allows multiplication of a huge number of true-to-type propagules in a very short time and in a very limited space, as well as all year round, regardless of the climate. However, applying plant-tissue-culture techniques for the commercial propagation of plants may face a lot of obstacles or troubles that could result from technical, biological, physiological, and/or genetical reasons, or due to overproduction or the lack of facilities and professional technicians, as shown in the current study. Moreover, several disorders and abnormalities are discussed in the present review. This study aims to show the most serious problems and obstacles of plant micropropagation, and their solutions from both scientific and technical sides. This review, as a first report, includes different challenges in plant micropropagation (i.e., contamination, delay of subculture, burned plantlets, browning, in vitro rooting difficulty, somaclonal variations, hyperhydricity, shoot tip necrosis, albino plantlets, recalcitrance, shoot abnormalities, in vitro habituation) in one paper. Most of these problems are related to scientific and/or technical reasons, and they could be avoided by following the micropropagation protocol suitable for each plant species. The others are dominant in plant-tissue-culture laboratories, in which facilities are often incomplete, or due to poor infrastructure and scarce funds. Full article

(This article belongs to the Special Issue Plant Tissue and Organ Cultures for Crop Improvement in Omics Era)

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20 pages, 1413 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Potency of Titanium Dioxide Nanoparticles, Sodium Hydrogen Sulfide and Salicylic Acid in Ameliorating the Depressive Effects of Water Deficit on Periwinkle Ornamental Quality

by Nahid Zomorrodi, Abdolhossein Rezaei Nejad, Sadegh Mousavi-Fard, Hassan Feizi, Georgios Tsaniklidis and Dimitrios Fanourakis

Horticulturae 2022, 8(8), 675; https://doi.org/10.3390/horticulturae8080675 - 24 Jul 2022

Cited by 12 | Viewed by 2084

Abstract

In this study, the optimal concentration of sodium hydrosulfide (NaSH), salicylic acid (SA), and titanium dioxide nanoparticles (TiO₂NPs), and their relative effectiveness on alleviating the adverse effects of water deficit on ornamental quality, were investigated in periwinkle. Plants were cultivated under [...] Read more.

In this study, the optimal concentration of sodium hydrosulfide (NaSH), salicylic acid (SA), and titanium dioxide nanoparticles (TiO₂NPs), and their relative effectiveness on alleviating the adverse effects of water deficit on ornamental quality, were investigated in periwinkle. Plants were cultivated under three water deficit levels (80, 50, and 20% available water content) and received two foliar applications of TiO₂NPs (0, 0.5 and 1 mM), NaSH (0.5 and 1 mM), or SA (1 and 2 mM). Water deficit deteriorated ornamental quality, amplified the risk of buckling (lower stem strength) and suppressed longevity. It decreased both light interception (leaf area) and carbon assimilation. Besides impaired hydration status, water-stressed plants underwent oxidative damage as indicated by reduced chlorophyll content, elevated membrane degradation, and lipid peroxidation. Spray treatments improved all traits, besides stem strength and proline content. Additionally, they enhanced carotenoid content and the activities of catalase and peroxidase. Their relative effectiveness (TiO₂NPs > NaSH > SA) and optimal concentration (i.e., 0.5 mM (TiO₂NPs, NaSH), and 1 mM (SA)) was independent of water deficit level. In conclusion, this study provides practices for improved ornamental quality and longevity independently of water availability, with their positive effect being stronger under irregular or limited water supply. Full article

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

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17 pages, 3158 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Bark Extract of Uncaria tomentosa L. for the Control of Strawberry Phytopathogens

by Eva Sánchez-Hernández, Pablo Martín-Ramos, Jesús Martín-Gil, Alberto Santiago-Aliste, Salvador Hernández-Navarro, Rui Oliveira and Vicente González-García

Horticulturae 2022, 8(8), 672; https://doi.org/10.3390/horticulturae8080672 - 23 Jul 2022

Cited by 16 | Viewed by 2679

Abstract

Gray mold (Botrytis cinerea Pers.), crown and fruit rot (Phytophthora cactorum (Lebert and Cohn) J.Schröt), and verticillium wilt (Verticillium dahliae Kleb.) are among the main diseases that affect the strawberry crop. In the study presented herein, the bark extract of [...] Read more.

Gray mold (Botrytis cinerea Pers.), crown and fruit rot (Phytophthora cactorum (Lebert and Cohn) J.Schröt), and verticillium wilt (Verticillium dahliae Kleb.) are among the main diseases that affect the strawberry crop. In the study presented herein, the bark extract of Uncaria tomentosa (Willd. ex Schult.) DC, popularly known as “cat’s claw”, has been evaluated for its capability to act as a sustainable control method. The bioactive compounds present in the aqueous ammonia extract were characterized by gas chromatography–mass spectroscopy, and the antimicrobial activity of the extract—alone and in combination with chitosan oligomers (COS)—was assessed in vitro and as a coating for postharvest treatment during storage. Octyl isobutyrate (30.7%), 19α methyl-2-oxoformosanan-16-carboxylate (9.3%), tetrahydro-2-methyl-thiophene (4.7%), and α-methyl manofuranoside (4.4%) were identified as the main phytoconstituents. The results of in vitro growth inhibition tests showed that, upon conjugation of the bark extract with COS, complete inhibition was reached at concentrations in the 39–93.75 μg∙mL⁻¹ range, depending on the pathogen. Concerning the effect of the treatment as a coating to prolong the storage life and control decay during post-harvest storage, high protection was observed at a concentration of 1000 μg∙mL⁻¹. Because of this effectiveness, higher than that attained with conventional synthetic fungicides, the bark extracts of cat’s claw may hold promise for strawberry crop protection. Full article

(This article belongs to the Special Issue Bioactivity, Phytochemical and Nutritional Composition of Natural Products)

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16 pages, 4864 KiB

Open AccessEditor’s ChoiceArticle

Multi-Band-Image Based Detection of Apple Surface Defect Using Machine Vision and Deep Learning

by Yan Tang, Hongyi Bai, Laijun Sun, Yu Wang, Jingli Hou, Yonglong Huo and Rui Min

Horticulturae 2022, 8(7), 666; https://doi.org/10.3390/horticulturae8070666 - 21 Jul 2022

Cited by 6 | Viewed by 2095

Abstract

Accurate surface defect extraction of apples is critical for their quality inspection and marketing purposes. Using multi-band images, this study proposes a detection method for apple surface defects with a combination of machine vision and deep learning. Five single bands, 460, 522, 660, [...] Read more.

Accurate surface defect extraction of apples is critical for their quality inspection and marketing purposes. Using multi-band images, this study proposes a detection method for apple surface defects with a combination of machine vision and deep learning. Five single bands, 460, 522, 660, 762, and 842 nm, were selected within the visible and near-infrared. By using a near-infrared industrial camera with optical filters, five single-band images of an apple could be obtained. To achieve higher accuracy of defect extraction, an improved U-Net was designed based on the original U-Net network structure. More specially, the partial original convolutions were replaced by dilated convolutions with different dilated rates, and an attention mechanism was added. The loss function was also redesigned during the training process. Then the traditional algorithm, the trained U-Net and the trained improved U-Net were used to extract defects of apples in the test set. Following that, the performances of the three methods were compared with that of the manual extraction. The results show that the near-infrared band is better than the visible band for defects with insignificant features. Additionally, the improved U-Net is better than the U-Net and the traditional algorithm for small defects and defects with irregular edges. On the test set, for single-band images at 762 nm, the improved U-Net had the best defect extraction with an mIoU (mean intersection over union) and mF1-score of 91% and 95%, respectively. Full article

(This article belongs to the Special Issue Innovative Nondestructive Techniques to Improve Quality Measurement of Fruits and Vegetables)

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18 pages, 1312 KiB

Open AccessEditor’s ChoiceArticle

The Emotional Experience of Flowers: Zoomed In, Zoomed Out and Painted

by Jacqueline Urakami, Ephrat Huss, Mitsue Nagamine, Johanna Czamanski-Cohen and Michele Zaccai

Horticulturae 2022, 8(7), 668; https://doi.org/10.3390/horticulturae8070668 - 21 Jul 2022

Viewed by 3495

Abstract

People have an ancient and strong bond to flowers, which are known to have a positive effect on the mood. During the COVID-19 pandemic, sales of ornamental plants increased, and many turned to gardening, possibly as a way to cope with ubiquitous increases [...] Read more.

People have an ancient and strong bond to flowers, which are known to have a positive effect on the mood. During the COVID-19 pandemic, sales of ornamental plants increased, and many turned to gardening, possibly as a way to cope with ubiquitous increases in negative mood following lockdowns and social isolation. The nature of the special bond between humans and flowers requires additional elucidation. To this means, we conducted a comprehensive online mixed methods study, surveying 253 individuals (ages 18–83) from diverse ethnic backgrounds and continents, regarding their thoughts and feelings towards photos of flowers, nature scenes and flower drawings. We found that looking at pictures and drawings of flowers, as well as nature scenes induced positive emotions, and participants reported a variety of positive responses to the images. More specifically, we found associations of flowers with femininity, and connotations to particular flowers that were affected by geographical location. While nature scene photos induced positive reactions, flower photos were preferred, denying a mere substitution of nature by flowers and vice versa. Drawings of flowers elicited less positive emotions than photos, as people related more to the art than to the flower itself. Our study reveals the importance of ornamental flowers and nature in our life and well-being, and as such their cultivation and promotion are essential. Full article

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

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12 pages, 257 KiB

Open AccessEditor’s ChoiceReview

Effects of Potassium Deficiency on the Growth of Tea (Camelia sinensis) and Strategies for Optimizing Potassium Levels in Soil: A Critical Review

by Wei Huang, Minyao Lin, Jinmei Liao, Ansheng Li, Wugyan Tsewang, Xuan Chen, Binmei Sun, Shaoqun Liu and Peng Zheng

Horticulturae 2022, 8(7), 660; https://doi.org/10.3390/horticulturae8070660 - 20 Jul 2022

Cited by 9 | Viewed by 3413

Abstract

Potassium is among the three essential macronutrients for tea plants, along with nitrogen and phosphorous, and plays important roles in growth and stress response. Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, [...] Read more.

Potassium is among the three essential macronutrients for tea plants, along with nitrogen and phosphorous, and plays important roles in growth and stress response. Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, calcium. At present, more than 59% of China’s tea gardens are in a state of potassium deficiency, which negatively affects tea quality and yield. This paper reviews the effects of potassium deficiency on tea plant growth and stress response, details factors affecting potassium supply and demand in tea gardens, examines the interactions between potassium and other elements in soils, and provides strategies for optimizing potassium levels in soils. Potassium is positively correlated with the elements nitrogen, copper, and zinc. Sufficient potassium dramatically improves the yield and quality of tea: it accelerates metabolism, promotes synthesis of catechins, and strengthens biotic and abiotic resistance by activating and regulating different enzymes. Moderate application of potassium fertilizers, along with potassium-solubilizing bacteria, can regulate the ratio of different forms of potassium and increase available potassium in soils of tea gardens. We suggest that research on potassium occurring in soils and its interaction with other elements be strengthened, so as to improve the efficient use of potassium fertilizers in tea gardens and maintain the balance of elements in soils. Full article

(This article belongs to the Section Plant Nutrition)

10 pages, 2410 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Iodine Enhances the Nutritional Value but Not the Tolerance of Lettuce to NaCl

by Giuseppe Maglione, Ermenegilda Vitale, Giulia Costanzo, Franca Polimeno, Carmen Arena and Luca Vitale

Horticulturae 2022, 8(7), 662; https://doi.org/10.3390/horticulturae8070662 - 20 Jul 2022

Cited by 6 | Viewed by 1545

Abstract

Positive stress or essential and nonessential elements can improve nutritive values (biofortification) of edible plants. In the present study, we evaluate (i) the effect of moderate salinity on lettuce biofortification, evaluated as nutritional bioactive compound accumulation, and (ii) the role of iodine in [...] Read more.

Positive stress or essential and nonessential elements can improve nutritive values (biofortification) of edible plants. In the present study, we evaluate (i) the effect of moderate salinity on lettuce biofortification, evaluated as nutritional bioactive compound accumulation, and (ii) the role of iodine in enhancing salt tolerance by increasing photorespiration and the content of antioxidants in lettuce. Physiological (gas exchange and chlorophyll fluorescence emission) and biochemical (photosynthetic pigment and bioactive compound) analyses were performed on lettuce plants grown under moderate salinity (50 mM NaCl alone or 50 mM NaCl in combination with iodine, KIO₃). Our results show that NaCl + iodine treatment improves the nutritional value of lettuce in terms of bioactive compounds acting as antioxidants. More specifically, iodine enhances the accumulation of photosynthetic pigments and polyphenols, such as anthocyanins, under salt but does not improve the salt tolerance. Our findings indicate that iodine application under moderate salinity could be a valid strategy in plant biofortification by improving nutritional bioactive compound accumulation, thus exercising functional effects on human health. Full article

(This article belongs to the Special Issue Horticultural Plants Facing Stressful Conditions - Ways of Stress Mitigation)

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15 pages, 1459 KiB

Open AccessFeature PaperEditor’s ChoiceReview

The SSR Null Allele Problem, and Its Consequences in Pedigree Reconstruction and Population Genetic Studies in Viticulture

by Gizella Jahnke, József Smidla, Tamás Deák, Róbert Oláh, Barna Árpád Szőke and Diána Ágnes Nyitrainé Sárdy

Horticulturae 2022, 8(7), 658; https://doi.org/10.3390/horticulturae8070658 - 19 Jul 2022

Cited by 2 | Viewed by 2596

Abstract

Null alleles are alleles that are recessive to codominant markers without any effect on the phenotype. In SSR assays, there are several reasons for the lack of amplification at a locus: the primer does not bind well, longer fragments do not amplify due [...] Read more.

Null alleles are alleles that are recessive to codominant markers without any effect on the phenotype. In SSR assays, there are several reasons for the lack of amplification at a locus: the primer does not bind well, longer fragments do not amplify due to imperfections in the PCR reaction, or the amount of DNA in the sample is insufficient. In microsatellite studies, null alleles are mostly used in pedigree analysis and population genetics calculations such as diversity estimation. Null alleles in pedigree analysis can cause rejection of the true parent; if not recognized while in population genetics they distort the results in underestimating diversity. In this review, the effects caused by null-alleles in viticultural research and its possible solutions were summarized. Full article

(This article belongs to the Section Viticulture)

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12 pages, 1551 KiB

Open AccessEditor’s ChoiceArticle

Response of Common Ice Plant (Mesembryanthemum crystallinum L.) to Photoperiod/Daily Light Integral in Vertical Hydroponic Production

by Jiaqi Xia and Neil Mattson

Horticulturae 2022, 8(7), 653; https://doi.org/10.3390/horticulturae8070653 - 19 Jul 2022

Cited by 4 | Viewed by 2765

Abstract

Common ice plant (Mesembryanthemum crystallinum L.) is a novel edible plant with a succulent and savory flavor emerging as new crop for greenhouse and plant factory growers. Currently very limited information is available on the response of ice plant to photoperiod and [...] Read more.

Common ice plant (Mesembryanthemum crystallinum L.) is a novel edible plant with a succulent and savory flavor emerging as new crop for greenhouse and plant factory growers. Currently very limited information is available on the response of ice plant to photoperiod and to daily light integral (DLI). The objective of this study was to determine the impact of photoperiod/DLI on the growth of ice plant for indoor vertical production. Four-week old seedlings of ice plant were transplanted into vertical hydroponic systems and given five photoperiod/DLI treatments: 8/6.3, 12/9.5, 16/12.7, 20/15.8, and 24/19.0 h/mol·m⁻²·d⁻¹. Sequential destructive harvests to determine plant growth occurred 14, 21, and 28 days after lighting treatments began. Plants performed better with increasing photoperiod/DLI from 8 h/6.3 mol·m⁻²·d⁻¹ to 20 h/15.8 mol·m⁻²·d⁻¹. By day 28, shoot fresh weight increased from 160 g to 639 g as the photoperiod/DLI increased from 8 h/6.3 mol·m⁻²·d⁻¹ to 20 h/15.8 mol·m⁻²·d⁻¹. The continuous lighting treatment, 24 h/19 mol·m⁻²·d⁻¹, showed a negative effect on the plant fresh weight (FW) and dry weight (DW). Light treatment did not have obvious effects on shoot:root ratio and macronutrient uptake except that potassium (K) uptake decreased slightly with increased photoperiod/DLI. Plants receiving higher photoperiod/DLI showed the same number of leaves (indicating the same development stage) but had smaller, thicker, and darker green leaves compared to lower photoperiod/DLI treatments. Leaf water content was not affected by light treatment up to 20 h/15.8 mol·m⁻²·d⁻¹ but decreased at 24 h/19 mol·m⁻²·d⁻¹. Further research is needed to separate the physiological response of increasing/continuous photoperiod from the response of increasing DLI. Full article

(This article belongs to the Special Issue Controlled Environment Horticulture: Latest Advances and Future Prospects)

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13 pages, 1854 KiB

Open AccessEditor’s ChoiceArticle

Elicitor Activity of Curdlan and Its Potential Application in Protection of Hass Avocado Plants against Phytophthora cinnamomi Rands

by Nathalie Guarnizo, Andree Álvarez, Diego Oliveros, Oveimar Barbosa, Jordi Eras Joli, María Bianney Bermúdez-Cardona and Walter Murillo-Arango

Horticulturae 2022, 8(7), 646; https://doi.org/10.3390/horticulturae8070646 - 16 Jul 2022

Cited by 4 | Viewed by 1742

Abstract

Phytophthora cinnamomi causes one of the most important diseases in avocado crop and its chemical management represents 25% of the production cost per year. Induction of plant defense responses by elicitors is a promising strategy that is compatible with sustainable agriculture. This study [...] Read more.

Phytophthora cinnamomi causes one of the most important diseases in avocado crop and its chemical management represents 25% of the production cost per year. Induction of plant defense responses by elicitors is a promising strategy that is compatible with sustainable agriculture. This study aimed to evaluate the effect of curdlan application on the induction of defense responses in avocado plants against P. cinnamomi. The trials were conducted under greenhouse conditions, and curdlan leaf spraying was performed one day before the inoculation of the pathogen. The results showed that the application of elicitor significantly increased the protection of avocado plants against P. cinnamomi, decreasing the injury and wilting. The Curd + Phy treatment improved the defenses of plants by increasing the enzymes peroxidase (POD) and polyphenol oxidase (PPO) in the first 3 h after inoculation and increasing the enzymes superoxide dismutase (SOD) and phenylalanine ammonium lyase (PAL) 144 h after inoculation (p < 0.05). Also, chlorophyll and carotenoid content increased or remained stable in Curd + Phy treatment. Therefore, these results suggest that curdlan increases the protection against P. cinnamomi and its protection could be due to an increase in the activity of the enzymes related to the phenylpropanoid pathway as well as the effect on chlorophyll and carotenoids. Full article

(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)

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16 pages, 2278 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Characterizing the Spatial Uniformity of Light Intensity and Spectrum for Indoor Crop Production

by László Balázs, Zoltán Dombi, László Csambalik and László Sipos

Horticulturae 2022, 8(7), 644; https://doi.org/10.3390/horticulturae8070644 - 15 Jul 2022

Cited by 10 | Viewed by 2263

Abstract

Maintaining uniform photon irradiance distribution above the plant canopy is a fundamental goal in controlled environment agriculture (CEA). Spatial variation in photon irradiance below the light saturation point will drive differences in individual plant development, decreasing the economic value of the crop. Plant [...] Read more.

Maintaining uniform photon irradiance distribution above the plant canopy is a fundamental goal in controlled environment agriculture (CEA). Spatial variation in photon irradiance below the light saturation point will drive differences in individual plant development, decreasing the economic value of the crop. Plant growth is also affected by the spectral composition of light. So far, little attention has been paid to the quantification of the spatial variability in horticultural lighting applications. This work provides a methodology to benchmark and compare lighting installations used in indoor cultivation facilities. We measured the photon irradiance distributions underneath two typical grow light installations using a 10 × 10 measurement grid with 100 mm spacing. We calculated photon irradiance values for each grid point for 100 nm-wide blue, green, red and far-red wavebands covering the 400–800 nm range. We showed that the generally used uniformity metric defined as the minimum to average ratio of PPFD is not appropriate for the characterization of light uniformity in horticultural lighting applications. Instead, we propose to normalize photon irradiance to the maximum, analyze the histograms constructed from relative photon irradiance values and consider the light response of the cultivated crop while comparing the performance of CEA grow systems. Full article

(This article belongs to the Special Issue Innovative Technologies and Production Strategies for Sustainable Controlled Environment Horticulture)

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16 pages, 2316 KiB

Open AccessEditor’s ChoiceArticle

Root Morphological and Physiological Adaptations to Low Phosphate Enhance Phosphorus Efficiency at Melon (Cucumis melo L.) Seedling Stage

by Pengli Li, Jinyang Weng, Asad Rehman and Qingliang Niu

Horticulturae 2022, 8(7), 636; https://doi.org/10.3390/horticulturae8070636 - 14 Jul 2022

Cited by 5 | Viewed by 2011

Abstract

The high phosphorus (P) acquisition ability of crops can reduce their dependence on artificial inorganic phosphate (Pi) supplementation under Pi-limited conditions. Melon (Cucumis melo L.) is vulnerable to Pi deficiency. This study was carried out to explore the morphological and physiological responses [...] Read more.

The high phosphorus (P) acquisition ability of crops can reduce their dependence on artificial inorganic phosphate (Pi) supplementation under Pi-limited conditions. Melon (Cucumis melo L.) is vulnerable to Pi deficiency. This study was carried out to explore the morphological and physiological responses of melon to low-Pi stress under a hydroponic system. The results show that low-Pi stress significantly disturbed nutrient homeostasis, reduced P content, and resulted in iron accumulation in melon seedlings and brown iron plaque formation on the root surface. A nutrient pool of P and Fe formed on the roots to forage for more Pi under low-Pi conditions. Severe long-term low-Pi stress promoted primary root elongation and inhibited lateral root growth, which increased the longitudinal absorption zone of the roots. The decrease in P content of the roots upregulated the expression of the acid phosphatase (APase) gene and increased APase activity. The high-affinity phosphate transporter (Pht1) genes were also upregulated significantly. These morphological and physiological responses significantly increased Pi uptake rate and P utilization efficiency at the melon seedling stage. These findings will be useful for screening low-Pi-tolerant varieties and sustaining melon production in P-limited environments. Full article

(This article belongs to the Topic Physiological and Molecular Characterization of Crop Tolerance to Abiotic Stresses)

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21 pages, 892 KiB

Open AccessEditor’s ChoiceArticle

Growth and Mineral Relations of Beta vulgaris var. cicla and Beta vulgaris ssp. maritima Cultivated Hydroponically with Diluted Seawater and Low Nitrogen Level in the Nutrient Solution

by Martina Puccinelli, Giulia Carmassi, Luca Botrini, Antonio Bindi, Lorenzo Rossi, Juan Francisco Fierro-Sañudo, Alberto Pardossi and Luca Incrocci

Horticulturae 2022, 8(7), 638; https://doi.org/10.3390/horticulturae8070638 - 14 Jul 2022

Cited by 7 | Viewed by 2481

Abstract

There is an increasing interest in the use of seawater in horticulture. The objective of this study was to evaluate Beta vulgaris var. cicla (Swiss chard) and its wild ancestor B. vulgaris spp. maritima (sea beet) as potential crop species for seawater hydroponics [...] Read more.

There is an increasing interest in the use of seawater in horticulture. The objective of this study was to evaluate Beta vulgaris var. cicla (Swiss chard) and its wild ancestor B. vulgaris spp. maritima (sea beet) as potential crop species for seawater hydroponics or aquaponics. Both species were grown in a floating system for leaf production with recurrent harvests. The nutrient solutions contained different concentrations of nitrate (1 and 10 mM) and a synthetic sea salt (0 and 10 g L⁻¹), in a factorial design, where the saline solution with a low nitrate level intended to mimic the typical nutritional conditions of saltwater aquaponics. In both species, increasing the salinity or reducing the N level in the nutrient solution reduced the crop yield and total dry biomass. In both Swiss chard and sea beet, the use of saline water resulted in a lower leaf concentration of K, Ca, Cu, and Mn, and a greater content of Na and Cl. In Swiss chard, an increase in Na and Cl and a decrease in K leaf content were found in successive harvests. On average, sea beet showed a higher leaf production and accumulation of nitrate than Swiss chard. Full article

(This article belongs to the Collection Biosaline Agriculture)

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17 pages, 3481 KiB

Open AccessEditor’s ChoiceArticle

Effects of Shading Nets on Reactive Oxygen Species Accumulation, Photosynthetic Changes, and Associated Physiochemical Attributes in Promoting Cold-Induced Damage in Camellia sinensis (L.) Kuntze

by Shah Zaman, Jiazhi Shen, Shuangshuang Wang, Yu Wang, Zhaotang Ding, Dapeng Song, Hui Wang, Shibo Ding, Xu Pang and Mengqi Wang

Horticulturae 2022, 8(7), 637; https://doi.org/10.3390/horticulturae8070637 - 14 Jul 2022

Cited by 6 | Viewed by 1769

Abstract

Climate change and extreme weather affect tea growing. A competitive tea market needs quick, short-term solutions. This study evaluates the effects of various shade nets under mild and extreme cold stress on tea leaf physiology, photosynthetic alterations, antioxidant activities, and physiochemical characteristics. Tea [...] Read more.

Climate change and extreme weather affect tea growing. A competitive tea market needs quick, short-term solutions. This study evaluates the effects of various shade nets under mild and extreme cold stress on tea leaf physiology, photosynthetic alterations, antioxidant activities, and physiochemical characteristics. Tea plants were treated with SD0 (0% non-shading), SD1 (30% shading), SD2 (60% shading), and SD3 (75% shading). The 30%, 60%, and 75% shade nets shielded tea leaves from cold damage and reduced leaf injury during mild and extreme cold conditions compared with SD0% non-shading. Shading regulates photochemical capacity and efficiency and optimizes chlorophyll a and b, chlorophyll, and carotenoid contents. Moreover, carbon and nitrogen increased during mild cold and decreased in extreme cold conditions. Shading promoted antioxidant activity and physiochemical attributes. In fact, under 60% of shade, superoxide dismutase, peroxidase, catalase, and ω-3 alpha-linolenic acid were improved compared with SD0% non-shading during both mild and extreme cold conditions. From these findings, we hypothesized that the effect of different shades played an important role in the protection of tea leaves and alleviated the defense mechanism for “Zhong Cha 102” during exposure to a cold environment. Full article

(This article belongs to the Special Issue The Effects of Shade on Crops: From Greenhouse to Agrivoltaic)

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20 pages, 2591 KiB

Open AccessEditor’s ChoiceReview

Fusarium Dry Rot of Garlic Bulbs Caused by Fusarium proliferatum: A Review

by Laura Gálvez and Daniel Palmero

Horticulturae 2022, 8(7), 628; https://doi.org/10.3390/horticulturae8070628 - 12 Jul 2022

Cited by 12 | Viewed by 8131

Abstract

Fusarium dry rot (FDR) is a postharvest disease of garlic crops causing yield losses worldwide. Fusarium proliferatum has been identified as the main species causing the disease. Symptoms begin as small brown lesions with a dehydrated appearance that can progress to cover the [...] Read more.

Fusarium dry rot (FDR) is a postharvest disease of garlic crops causing yield losses worldwide. Fusarium proliferatum has been identified as the main species causing the disease. Symptoms begin as small brown lesions with a dehydrated appearance that can progress to cover the entire clove during the storage period. Symptoms on growing plants cause brown lesions on the basal plates and roots, and sometimes damping-off is observed. F. proliferatum is a polyphagous pathogen with a wide range of hosts. This pathogen colonizes garlic roots, remaining as a latent pathogen, and develops rot during storage. The pathogen can overwinter in the soil, infested crop residues, and weeds. The fungus can also persist on garlic cloves, acting as primary inoculum in the field and contributing to the long-distance spread. Using healthy plant material, rotating crops, burying crop residues, avoiding bulb injury during harvest and subsequent handling, and providing appropriate postharvest environmental conditions are crucial factors that greatly influence the disease severity. Choosing a suitable non-host crop to achieve truly effective rotation is sometimes difficult. Chemical control in the form of seed treatments or field spraying of the crop has a limited effect on controlling FDR. Field applications of biological control agents have shown some efficacy, but conditions to optimize their activity must be determined. Moreover, different soil management strategies to reduce soil inoculum must be also studied. Full article

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

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12 pages, 1455 KiB

Open AccessEditor’s ChoiceArticle

Oligosaccharins Used Together with Tebuconazole Enhances Resistance of Kiwifruit against Soft Rot Disease and Improves Its Yield and Quality

by Qiuping Wang, Youhua Long, Qiang Ai, Yue Su and Yang Lei

Horticulturae 2022, 8(7), 624; https://doi.org/10.3390/horticulturae8070624 - 11 Jul 2022

Cited by 4 | Viewed by 1454

Abstract

Botryosphaeria dothidea is one of the most frequent pathogens of soft rot disease in kiwifruit. The aim of this study was to investigate the role of oligosaccharins used together with tebuconazole to control soft rot and their influences on kiwifruit’s disease resistance, growth [...] Read more.

Botryosphaeria dothidea is one of the most frequent pathogens of soft rot disease in kiwifruit. The aim of this study was to investigate the role of oligosaccharins used together with tebuconazole to control soft rot and their influences on kiwifruit’s disease resistance, growth and quality. The results show that tebuconazole displayed a toxicity against B. dothidea RF-1 with 0.87 mg kg⁻¹ of EC₅₀ value. Oligosaccharins used together with tebuconazole effectively managed soft rot with 84.83% of the field management effect by spraying tebuconazole + oligosaccharins (0.5:0.5, m/v) as a 5000-fold dilution liquid, which significantly (p < 0.01) exceeded the 72.05%, 52.59%, 62.17% and 33.52% effect of tebuconazole 2500-, oligosaccharins 2500-, tebuconazole 5000- and oligosaccharins 5000-fold liquids, respectively. Simultaneously, co-application of tebuconazole and oligosaccharins was more effective for enhancing the resistance, growth and quality of kiwifruit compared with tebuconazole or oligosaccharins alone. This work highlights that oligosaccharins used together with tebuconazole can be proposed as a practicable measure for managing kiwifruit soft rot and reducing the application of chemical synthetic fungicides. Full article

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

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10 pages, 569 KiB

Open AccessEditor’s ChoiceReview

Human Health Benefits through Daily Consumption of Jerusalem Artichoke (Helianthus tuberosus L.) Tubers

by Angela Méndez-Yáñez, Patricio Ramos and Luis Morales-Quintana

Horticulturae 2022, 8(7), 620; https://doi.org/10.3390/horticulturae8070620 - 8 Jul 2022

Cited by 2 | Viewed by 5455

Abstract

“Let food be thy medicine and medicine be thy food”, is one of the most famous phrases attributed to Hippocrates, the father of medicine. Scientific research on superfoods has increased in the last six years. These foods have nutritional and pharmacological properties, such [...] Read more.

“Let food be thy medicine and medicine be thy food”, is one of the most famous phrases attributed to Hippocrates, the father of medicine. Scientific research on superfoods has increased in the last six years. These foods have nutritional and pharmacological properties, such that they can help to fight against diseases and poor nutritional status. Helianthus tuberosus L., or Jerusalem artichoke, appears to be a superfood that provides benefits to human health at the level of the digestive, gastrointestinal, and dermatological systems, being fit for patients with diabetes mellitus due to its high content of inulin and use in an optimal hypocaloric diet due to its low carbohydrate content. In fact, 5 to 15 g per day is beneficial, with evidence of a prebiotic effect. Unfortunately, its consumption and cultivation are not well known worldwide. For this reason, the present review describes the benefits of H. tuberosus in human health to promote knowledge about its nutritional benefits. Full article

(This article belongs to the Collection Nutritional Quality of Fruits and Vegetables)

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14 pages, 8843 KiB

Open AccessEditor’s ChoiceArticle

In Vitro and In Vivo Performance of Plum (Prunus domestica L.) Pollen from the Anthers Stored at Distinct Temperatures for Different Periods

by Milena Đorđević, Tatjana Vujović, Radosav Cerović, Ivana Glišić, Nebojša Milošević, Slađana Marić, Sanja Radičević, Milica Fotirić Akšić and Mekjell Meland

Horticulturae 2022, 8(7), 616; https://doi.org/10.3390/horticulturae8070616 - 7 Jul 2022

Cited by 5 | Viewed by 1893

Abstract

A study was conducted to investigate the effect of different storage periods and temperatures on pollen viability in vitro and in vivo in plum genotypes ‘Valerija’, ‘Čačanska Lepotica’ and ‘Valjevka’. In vitro pollen viability was tested at day 0 (fresh dry pollen) and [...] Read more.

A study was conducted to investigate the effect of different storage periods and temperatures on pollen viability in vitro and in vivo in plum genotypes ‘Valerija’, ‘Čačanska Lepotica’ and ‘Valjevka’. In vitro pollen viability was tested at day 0 (fresh dry pollen) and after 3, 6, 9 and 12 months of storage at four different temperatures (4, −20, −80 and −196 °C), and in vivo after 12 months of storage at distinct temperatures. In vitro germination and fluorescein diacetate (FDA) staining methods were used to test pollen viability, while aniline blue staining was used for observing in vivo pollen tube growth. Fresh pollen germination and viability ranged from 42.35 to 63.79% (‘Valjevka’ and ‘Čačanska Lepotica’, respectively) and 54.58 to 62.15%, (‘Valjevka’ and ‘Valerija’, respectively). With storage at 4 °C, pollen viability and germination decreased over the period, with the lowest value after 12 months of storage. Pollen germination and viability for the other storage temperatures (−20, −80 and −196 °C) were higher than 30% by the end of the 12 months. Pollination using pollen stored at 4 °C showed that pollen tube growth mostly ended in the lower part of the style. With the other storage temperatures, pollen tube growth was similar, ranging between 50 and 100% of the pistils with pollen tubes penetrated into the nucellus of the ovule in the genotype ‘Čačanska Lepotica’. The results of these findings will have implications for plum pollen breeding and conservation. Full article

(This article belongs to the Special Issue In Vitro Regeneration, Micropropagation and Germplasm Conservation of Horticultural Plants)

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17 pages, 6356 KiB

Open AccessEditor’s ChoiceArticle

Influence of Citrus Rootstocks on Scion Growth, Hormone Levels, and Metabolites Profile of ‘Shatangju’ Mandarin (Citrus reticulata Blanco)

by Faisal Hayat, Juan Li, Wen Liu, Caiqing Li, Wenpei Song, Shahid Iqbal, Ummara Khan, Hafiz Umer Javed, Muhammad Ahsan Altaf, Panfeng Tu, Jiezhong Chen and Jianliang Liu

Horticulturae 2022, 8(7), 608; https://doi.org/10.3390/horticulturae8070608 - 6 Jul 2022

Cited by 16 | Viewed by 2739

Abstract

Dwarfing rootstocks are a valuable genetic resource for managing high-density plantations. The selection of the appropriate scion/rootstock combination is key to improving crop performance and sustainable production in a particular environment and specific training systems. ‘Shatangju’ mandarin scion cultivar grafted onto ‘Flying Dragon’ [...] Read more.

Dwarfing rootstocks are a valuable genetic resource for managing high-density plantations. The selection of the appropriate scion/rootstock combination is key to improving crop performance and sustainable production in a particular environment and specific training systems. ‘Shatangju’ mandarin scion cultivar grafted onto ‘Flying Dragon’ rootstock tends to be dwarfing and develops short stature plants. To obtain insight into potential mechanisms underlying rootstock-induced dwarfing effects, we conducted a rootstock trial to examine the influence of 11 different rootstocks based on their growth vigor, antioxidants, and hormonal levels of the scion cultivar. The phenotypic observations revealed that size reduction in the ‘Flying Dragon’ rootstock is due to lower node number, shorter internodal length, and a reduced trunk diameter of the scion compared with more vigorous rootstocks. Antioxidant analysis showed that ‘Shatangju’ mandarin grafted onto ’Flying Dragon’ and ‘Trifoliate Orange’ rootstock had significantly lower peroxidase (POD) activity than other tested rootstocks. The hormonal analysis indicated that there were markedly lower amounts of abscisic acid (ABA) in ‘Shatangju’ mandarin grafted with ‘Flying Dragon’ rootstock. In addition, trees grafted with ‘Sour Pummelo’ and ‘Flying Dragon’ depicted minimum amounts of gibberellins (GA₂₄). Moreover, several metabolites associated with organic acids, flavonoids, amino acids, and alkaloids responded differently in plants grafted with ‘Flying Dragon’ (dwarfing) and ‘Shatang Mandarin’ (vigorous) rootstocks. This study concluded that ‘Flying Dragon’ rootstock with a strong dwarfing effect has been proposed to improve high-density cultivation methods. These findings will provide useful insights for future research associated with rootstock-mediated dwarfing mechanisms of citrus rootstocks. Full article

(This article belongs to the Special Issue New Insights into Rootstock - Scion Interactions in Horticultural Crops)

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32 pages, 518 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Postharvest Technologies of Fresh Citrus Fruit: Advances and Recent Developments for the Loss Reduction during Handling and Storage

by Maria Concetta Strano, Giuseppe Altieri, Maria Allegra, Giovanni Carlo Di Renzo, Giuliana Paterna, Attilio Matera and Francesco Genovese

Horticulturae 2022, 8(7), 612; https://doi.org/10.3390/horticulturae8070612 - 6 Jul 2022

Cited by 35 | Viewed by 10858

Abstract

Citrus spp. are spread mainly in the Mediterranean basin and represent the largest fruit source for human consumption. Postharvest losses, mainly due to diseases and metabolic disorders of fruits, can cause severe wastage, reaching 30 to 50% of the total production. Preserving quality [...] Read more.

Citrus spp. are spread mainly in the Mediterranean basin and represent the largest fruit source for human consumption. Postharvest losses, mainly due to diseases and metabolic disorders of fruits, can cause severe wastage, reaching 30 to 50% of the total production. Preserving quality and extending shelf life are essential objectives for postharvest technological innovation, determined by the proper handling, treatment, storage and transport of harvested produce. Moreover, the application of novel sustainable strategies is critical for the reduction of synthetic fungicide residues on fruit surfaces and the impact on the environment caused by waste disposal of fungicides. In this article, the current knowledge about the safest and more sustainable strategies, as well as advanced postharvest handling and storage technologies, will be critically reviewed. Full article

(This article belongs to the Special Issue Postharvest Management of Citrus Fruit)

21 pages, 2759 KiB

Open AccessEditor’s ChoiceArticle

Molecular Characterization of Tomato (Solanum lycopersicum L.) Accessions under Drought Stress

by Ibrahim Makhadmeh, Ammar A. Albalasmeh, Mohammed Ali, Samar G. Thabet, Walaa Ali Darabseh, Saied Jaradat and Ahmad M. Alqudah

Horticulturae 2022, 8(7), 600; https://doi.org/10.3390/horticulturae8070600 - 4 Jul 2022

Cited by 5 | Viewed by 2756

Abstract

Exploring the genetic diversity among plant accessions is important for conserving and managing plant genetic resources. In the current study, a collection of forty-six tomato accessions from Jordan were evaluated based on their performance and their morpho-physiological, in addition to molecularly characterizing to [...] Read more.

Exploring the genetic diversity among plant accessions is important for conserving and managing plant genetic resources. In the current study, a collection of forty-six tomato accessions from Jordan were evaluated based on their performance and their morpho-physiological, in addition to molecularly characterizing to detect genetic diversity. Tomato accessions seedlings were exposed to drought stress with 70% field capacity and 40% field capacity under field conditions in Jordan. Drought stress had significantly negatively influenced the dry root weight, fresh root weight, root growth rate, fresh shoot weight, dry shoot weight, and shoot growth rate. Moreover, proline content showed a highly significant increase of 304.2% in response to drought stress. The analysis of twenty morphological characters revealed a wide range of variations among tomato accessions. Accessions were screened with fourteen SSR primers; six primers were informative to explain the genetic diversity. Based on resolving power, primers LEct004 and LEat018 were most significant with all 46 accessions. Interestingly, polymorphic information content (PIC) values ranged from 0.00 (Asr2 marker) to 0.499 (LEct004), which confirms that the SSR markers are highly informative. Our findings provide new insights into using informative molecular markers to elucidate such wide genetic variation discovered in our collections from Afraa and Abeel (the southern part of Jordan). Interestingly, the SSR markers were associated with genes, e.g., LEat018 with ACTIN_RELATED PROTEIN gene, the LEct004 with the HOMEOBOX PROTEIN TRANSCRIPTION FACTORS gene, and Asr2 with ABA/WDS. Moreover, the AUXIN RESPONSE FACTOR8 gene was associated with the LEta014 SSR marker and the LEta020 with the THIOREDOXIN FAMILY TRP26 gene. Therefore, the genetic diversity analysis and functional annotations of the genes associated with SSR information obtained in this study provide valuable information about the most suitable genotype that can be implemented in plant breeding programs and future molecular analysis. Furthermore, evaluating the performance of the collection under different water regimes is essential to produce new tomato varieties coping with drought stress conditions. Full article

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

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16 pages, 1454 KiB

Open AccessEditor’s ChoiceArticle

Foliar Application of Selenium under Nano Silicon on Artemisia annua: Effects on Yield, Antioxidant Status, Essential Oil, Artemisinin Content and Mineral Composition

by Nadezhda Golubkina, Lidia Logvinenko, Dmitry Konovalov, Ekaterina Garsiya, Mikhail Fedotov, Andrey Alpatov, Oksana Shevchuk, Liubov Skrypnik, Agnieszka Sekara and Gianluca Caruso

Horticulturae 2022, 8(7), 597; https://doi.org/10.3390/horticulturae8070597 - 2 Jul 2022

Cited by 9 | Viewed by 1981

Abstract

The unique biological properties of A. annua have stimulated the research on its cultivation in different regions of the world. In this study, the effect of the Se and nano-Si supply on the yield, biochemical characteristics and mineral content of A. annua was [...] Read more.

The unique biological properties of A. annua have stimulated the research on its cultivation in different regions of the world. In this study, the effect of the Se and nano-Si supply on the yield, biochemical characteristics and mineral content of A. annua was investigated. Growth stimulation and a significant increase in the antioxidant status were recorded under Se and nano-Si foliar application. A decrease in the number of essential oil components and significant changes in the essential oil amount and composition led to significant phenophase shifts: nano-Si significantly stimulated eucalyptol and artemisia ketone accumulation and decreased germacrene D production, whereas Se demonstrated the opposite effect. A joint Se and nano-Si supply significantly decreased the camphor content and increased artemisia ketone and artemisinin levels by 1.3–1.5 times. Se/Si supplementation affected the macro- and microelements content, causing either a redistribution of leaves/stems elements (Al, Li and Zn) or a significant decrease in Ca, Mg, K, B, Cu, Fe and Mn concentrations in leaves, with no signs in growth inhibition or a decrease in the photosynthetic pigments content. The biofortification of A. annua with Se singly or in combination with nano-Si resulted in the synthesis of products with a Se content of as much as approximately 16% of the daily adequate Se consumption level (ACL) when using 5 g day⁻¹ as a spice, or 36% of ACL when using 50 mL of tea infusion (1:2, v/w). The results indicated a high possibility of Se and nano-Si application toward the regulation of A. annua growth, biochemical characteristics (including essential oil and artemisinin) and mineral content. Full article

(This article belongs to the Special Issue Vegetable Biofortification: Strategies, Benefits and Challenges)

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16 pages, 2531 KiB

Open AccessEditor’s ChoiceArticle

Integrated Metabolomic and Transcriptomic Analysis Reveals the Effect of Artificial Shading on Reducing the Bitter Taste of Bamboo Shoots

by Yongjian Huang, Hang Xun, Guilin Yi, Ti Li, Xi Yao and Feng Tang

Horticulturae 2022, 8(7), 594; https://doi.org/10.3390/horticulturae8070594 - 1 Jul 2022

Cited by 2 | Viewed by 2152

Abstract

Bamboo shoot is a delicious and nutritious forest vegetable. It has been found that bamboo shoots collected from low-light environments have a less bitter taste. The molecular mechanism of light in the regulation of bitter substance accumulation in bamboo shoots is still unclear. [...] Read more.

Bamboo shoot is a delicious and nutritious forest vegetable. It has been found that bamboo shoots collected from low-light environments have a less bitter taste. The molecular mechanism of light in the regulation of bitter substance accumulation in bamboo shoots is still unclear. In this study, we applied a shading treatment to Pleioblastus amarus bamboo shoots in the preharvesting period. The reduction in the bitterness intensity was confirmed by a sensory test. An integrated metabolomic and transcriptomic analysis was performed on P. amarus bamboo shoots grown under shading treatment and normal growing conditions, and 56 differentially accumulated metabolites and 178 differentially expressed genes were identified. The results showed that the contents of a series of phenolic acids related to the tyrosine metabolism pathway were downregulated under shading treatment, revealing that shading decreased the accumulation of phenolic acids and further mediated the resulting bitter taste of the bamboo shoots. This work will be helpful for understanding the regulatory mechanisms governing the bitter tasting substances in bamboo shoots grown under a shading treatment and provides a reference for the use of shading treatment in cultivation practices to improve the taste of bamboo shoots. Full article

(This article belongs to the Special Issue Omics Technologies and Their Applications in Vegetable Plant Research)

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16 pages, 5407 KiB

Open AccessEditor’s ChoiceArticle

Comprehensive Evaluation of Low Temperature and Salt Tolerance in Grafted and Rootstock Seedlings Combined with Yield and Quality of Grafted Tomato

by Shijie Fu, Jiaqian Chen, Xiaolei Wu, Hongbo Gao and Guiyun Lü

Horticulturae 2022, 8(7), 595; https://doi.org/10.3390/horticulturae8070595 - 1 Jul 2022

Cited by 5 | Viewed by 1979

Abstract

Environmental stress, especially in the form of low temperatures and salinity, has becomethe main limiting factor affecting the yield and quality of tomatoes in greenhouse production in China. Grafting, as an effective and sustainable strategy for improving plant stress tolerance, is closely related [...] Read more.

Environmental stress, especially in the form of low temperatures and salinity, has becomethe main limiting factor affecting the yield and quality of tomatoes in greenhouse production in China. Grafting, as an effective and sustainable strategy for improving plant stress tolerance, is closely related to rootstock properties and scion affinity. Here, 15 commercial rootstock genotypes were collected to investigate the differences in low temperatures and salt tolerance of rootstocks and grafted tomato seedlings in parallel, as well as well as the effect of grafting on the yield and quality of tomato. The results indicated that there were differences among rootstocks, and the resistance of grafted seedlings mainly depended on the characteristics of the rootstocks. We also found that the resistance of grafted seedlings was affected by the affinity between the scion and rootstock. Genotypes 6, 7, 11, and 14 showed advantages over the other genotypes in seedling growth, based on the fresh weight of the plants, the seedling index, and the root-shoot ratio. Genotypes 2, 7, 11, and 14 had greater total root lengths and higher numbers of root tips than other genotypes. These results showed that the significant increase in growth in the grafted tomato seedlings might have been attributable to the vigorous roots of the rootstocks. Genotypes 4, 7, 11, and 13 showed advantages with respect to low temperature stress, whereas genotypes 7, 11, 12, and 13 showed advantages with respect to salt stress. The salt tolerance of grafted tomato seedlings was influenced by both scion affinity and rootstock characteristics and was decreased by grafting. The highest yields were obtained from the grafted plants of genotypes 7 and 11, whose yields were 17.2% and 14.6% higher, respectively, than those of the control group. The rootstock genotype did not affect the fruit quality parameters, such as soluble protein content, titratable acidity, and total soluble solids content, and in most cases, the lycopene and ascorbic acid contents of the fruit increased. After considering the results pertaining to the stress tolerance of rootstocks in combination with fruit yield and quality, genotypes 7 and 11 were selected as potentially suitable tomato rootstock varieties for further large-scale applications. These results provide a new perspective for the study of rootstock characteristics and an important reference for grafted tomato cultivation in greenhouse production. Full article

(This article belongs to the Special Issue Advances in Protected Vegetable Cultivation)

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21 pages, 5582 KiB

Open AccessEditor’s ChoiceArticle

A Lignin-Rich Extract of Giant Reed (Arundo donax L.) as a Possible Tool to Manage Soilborne Pathogens in Horticulture: A Preliminary Study on a Model Pathosystem

by Stefania Galletti, Stefano Cianchetta, Hillary Righini and Roberta Roberti

Horticulturae 2022, 8(7), 589; https://doi.org/10.3390/horticulturae8070589 - 30 Jun 2022

Cited by 6 | Viewed by 2004

Abstract

Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic [...] Read more.

Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic requirements. Some studies have already highlighted antimicrobial and antifungal properties of giant reed-derived compounds. This study aimed at investigating the potential of a lignin-rich giant reed extract for crop protection. The extract, obtained by dry biomass treatment with potassium hydroxide at 120 °C, followed by neutralization, was chemically characterized. A preliminary in vitro screening among several pathogenic strains of fungi and oomycetes showed a high sensitivity by most of the soilborne pathogens to the extract; thus, an experiment was performed with the model pathosystem, Pythium ultimum–zucchini in a growth substrate composed of peat or sand. The adsorption by peat and sand of most of the lignin-derived compounds contained in the extract was also observed. The extract proved to be effective in restoring the number of healthy zucchini plantlets in the substrate infected with P. ultimum compared to the untreated control. This study highlights the potential of the lignin-rich giant reed extract to sustain crop health in horticulture. Full article

(This article belongs to the Special Issue Sustainable Control Strategies of Plant Pathogens in Horticulture)

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24 pages, 5000 KiB

Open AccessEditor’s ChoiceArticle

Characteristics of Meteorological Conditions during a Severe Outbreak of Onion Downy Mildew and Metalaxyl Sensitivity of Peronospora destructor in Saga, Japan, in 2016

by Shin-ichirou Syobu and Sachiko Watanabe

Horticulturae 2022, 8(7), 578; https://doi.org/10.3390/horticulturae8070578 - 26 Jun 2022

Cited by 2 | Viewed by 2248

Abstract

In 2016, an onion downy mildew epidemic caused by Peronospora destructor severely damaged the commercial onion fields in Saga Prefecture, western Japan. To identify the factors underlying the outbreak, we investigated the symptoms of downy mildew caused by secondary infections and examined P. [...] Read more.

In 2016, an onion downy mildew epidemic caused by Peronospora destructor severely damaged the commercial onion fields in Saga Prefecture, western Japan. To identify the factors underlying the outbreak, we investigated the symptoms of downy mildew caused by secondary infections and examined P. destructor’s sensitivity to metalaxyl, the most effective traditional fungicide used against this onion pathogen, in 2016–2018. Disease symptoms developed in late March 2016, which was earlier than symptom development in 2017 and 2018. Furthermore, there were synchronous repeated disease development and favourable meteorological conditions for infection in early and late April resulting in the development of polycyclic epidemics. In field trials from 2016 to 2018, the efficacy of chlorothalonil + metalaxyl-M application ranged 18–45%, as calculated by comparing disease severity at the final stage of each treatment to that in the untreated plots. On the basis of the metalaxyl sensitivity observed in 2016, the effective concentration, which reduced germ-tube elongation in P. destructor by 50%, exceeded 200 µg ai/mL for certain strains. Our observations indicate that these characteristic meteorological conditions were major factors contributing to the severe disease outbreak in 2016. The emergence of less-metalaxyl-sensitive P. destructor strains may be an additional predisposing factor. Full article

(This article belongs to the Special Issue Horticultural Plants Pathology and Advances in Disease Management)

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19 pages, 2184 KiB

Open AccessEditor’s ChoiceArticle

Early-Summer Deficit Irrigation Increases the Dry-Matter Content and Enhances the Quality of Ambrosia™ Apples At- and Post-Harvest

by Changwen Lu

Horticulturae 2022, 8(7), 571; https://doi.org/10.3390/horticulturae8070571 - 23 Jun 2022

Cited by 1 | Viewed by 1712

Abstract

Ambrosia™ is an apple that naturally has limited post-harvest quality retention, which is accompanied by relatively low dry-matter content (DMC). This trial was proposed to improve the DMC of this apple by scheduling deficit irrigation (DI) conducted in a semi-arid orchard in the [...] Read more.

Ambrosia™ is an apple that naturally has limited post-harvest quality retention, which is accompanied by relatively low dry-matter content (DMC). This trial was proposed to improve the DMC of this apple by scheduling deficit irrigation (DI) conducted in a semi-arid orchard in the Similkameen Valley (British Columbia, Canada) in 2018 and 2019. Two irrigation regimes were implemented in the orchard: commercial irrigation (CI) and DI, which was defined as irrigation for 2/5 of the timespan of CI. Five irrigation treatments were conducted: 1—adequate irrigation (AI), which used CI for the whole season; 2—early-summer DI (ED), which used DI from 20 June to 20 July; 3—middle-summer DI (MD), which used DI from 20 July to 20 August; 4—late-summer DI (LD), which used DI from 20 August to 10 days before harvest; and 5—double-period DI (DD), which covered the interval of MD and LD. The DI treatments resulted in a significant decrease from AI −1.0 to −1.5 MPa in stem water potential (SWP), followed by subsequent recovery. Conversely, SWP did not recover, and instead reached a critical low of −2.5 MPa under continued deficit conditions (DD). This, in turn, correlated with significant differences in the DMC among the treatments. Specifically, ED resulted in a rapid and sustained increase in DMC throughout the summer. At the time of harvest, ED resulted in a five-fold increase in the proportion of fruit, with greater than 16% DMC and 15% DMC in 2018 and 2019, respectively, compared to AI. DD resulted in similar levels of DMC elevation compared to ED, but also caused irregular maturation and the increased incidence of soft scald disorder in the post-harvest period. MD and LD had variable effects on DMC, and also increased the incidence of soft scald disorder. Consequently, fruit collected from the ED resulted in the best blush color attributes, higher soluble solid content, and a significant improvement in the post-harvest retention of both fruit firmness and acidity. The ED irrigation model would be recommended as a practical way for Ambrosia™ growers in semi-arid regions to decrease water usage, and to ensure high fruit quality for superior marketing and sustainable production. Full article

(This article belongs to the Special Issue Irrigation and Water Management in Horticulture)

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15 pages, 3338 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of the Storage Performance of ‘Valencia’ Oranges and Generation of Shelf-Life Prediction Models

by Abiola Owoyemi, Ron Porat, Amnon Lichter, Adi Doron-Faigenboim, Omri Jovani, Noam Koenigstein and Yael Salzer

Horticulturae 2022, 8(7), 570; https://doi.org/10.3390/horticulturae8070570 - 22 Jun 2022

Cited by 4 | Viewed by 2022

Abstract

We conducted a large-scale, high-throughput phenotyping analysis of the effects of various preharvest and postharvest features on the quality of ‘Valencia’ oranges in order to develop shelf-life prediction models. Altogether, we evaluated 10,800 oranges (~3.6 tons) harvested from three orchards at different periods [...] Read more.

We conducted a large-scale, high-throughput phenotyping analysis of the effects of various preharvest and postharvest features on the quality of ‘Valencia’ oranges in order to develop shelf-life prediction models. Altogether, we evaluated 10,800 oranges (~3.6 tons) harvested from three orchards at different periods and conducted 151,200 measurements of 14 quality parameters. The storage time was the most important feature affecting fruit quality, followed by the yield, storage temperature, humidity, and harvest time. The storage time and temperature features significantly affected (p < 0.001) all or most of the tested quality parameters, whereas the harvest time, yield, and humidity conditions significantly affected several particular quality parameters, and the selection of rootstocks had no significant effect at all. Five regression models were evaluated for their ability to predict fruit quality based on preharvest and postharvest features. Non-linear Support Vector Regression (SVR) combined with a data-balancing approach was found to be the most effective approach. It allowed the prediction of fruit-acceptance scores among the full data set, with a root mean square error (RMSE) of 0.195 and an R² of 0.884. The obtained data and models should assist in determining the potential storage times of different batches of fruit. Full article

(This article belongs to the Special Issue Postharvest Management of Citrus Fruit)

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13 pages, 1301 KiB

Open AccessEditor’s ChoiceArticle

Enhancement of Anti-Inflammatory and Antioxidant Activities of Mango Fruit by Pre- and Postharvest Application of Salicylic Acid

by Si Thu Win and Sutthiwal Setha

Horticulturae 2022, 8(6), 555; https://doi.org/10.3390/horticulturae8060555 - 20 Jun 2022

Cited by 3 | Viewed by 2626

Abstract

Mango fruits have a high nutritional value and are beneficial to health. However, losses frequently occur after harvest, because they are perishable. Salicylic acid (SA) can be used to preserve fruit quality and maintain their nutritional contents. Therefore, this study was conducted to [...] Read more.

Mango fruits have a high nutritional value and are beneficial to health. However, losses frequently occur after harvest, because they are perishable. Salicylic acid (SA) can be used to preserve fruit quality and maintain their nutritional contents. Therefore, this study was conducted to investigate the effects of applications of 2 mM SA on the physicochemical properties, bioactive compounds, and antioxidant and anti-inflammatory activities of mango fruit. For this purpose, mango fruits received preharvest (Pre SA) or postharvest applications of SA (Post SA), or their combination (Pre + Post SA); the fruits were stored at 13 °C for 20 days. Weight loss, decay, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity were maintained in SA-treated fruit. The Pre + Post SA treatment was superior in delaying fruit ripening, and maintaining lower soluble solids contents and higher total acidity. In addition, total phenolic compounds, ferric reducing antioxidant power, and free radical scavenging activity of anti-inflammatory substances (such as nitric oxide), as well as hyaluronidase inhibition, were higher in the Pre + Post SA treatment throughout storage. Therefore, both pre- and postharvest SA treatments are recommended for preserving the quality of mango fruit, such as Nam Dok Mai Si Thong, and for maintaining their nutritional properties for human health. Full article

(This article belongs to the Special Issue Innovative Postharvest Treatment for Maintaining Quality of Horticultural Production)

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13 pages, 5073 KiB

Open AccessEditor’s ChoiceArticle

Antifungal Activity of Volatile Organic Compounds from Bacillus velezensis CE 100 against Colletotrichum gloeosporioides

by Vantha Choub, Sang-Jae Won, Henry B. Ajuna, Jae-Hyun Moon, Su-In Choi, Hyo-In Lim and Young Sang Ahn

Horticulturae 2022, 8(6), 557; https://doi.org/10.3390/horticulturae8060557 - 20 Jun 2022

Cited by 25 | Viewed by 3060

Abstract

Colletotrichum gloeosporioides is the most prevalent phytopathogen, causing anthracnose disease that severely affects the production of various fruit trees, including walnut and jujube. In this study, the volatile organic compounds (VOCs) from Bacillus velezensis CE 100 disrupted the cell membrane integrity of C. [...] Read more.

Colletotrichum gloeosporioides is the most prevalent phytopathogen, causing anthracnose disease that severely affects the production of various fruit trees, including walnut and jujube. In this study, the volatile organic compounds (VOCs) from Bacillus velezensis CE 100 disrupted the cell membrane integrity of C. gloeosporioides and reduced the spore germination by 36.4% and mycelial growth by 20.0% at a bacterial broth concentration of 10%, while the control group showed no antifungal effect. Based on the headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) analysis, seven VOCs were identified from the headspace of B. velezensis CE 100. Out of the seven VOCs, 5-nonylamine and 3-methylbutanoic acid were only detected in the headspace of B. velezensis CE 100 but not in the control group. Both 5-nonylamine and 3-methylbutanoic acid showed significant antifungal activity against the spore germination and mycelial growth of C. gloeosporioides. Treatment with 100 µL/mL of 5-nonylamine and 3-methylbutanoic acid suppressed the spore germination of C. gloeosporioides by 10.9% and 30.4% and reduced mycelial growth by 14.0% and 22.6%, respectively. Therefore, 5-nonylamine and 3-methylbutanoic acid are the potential antifungal VOCs emitted by B. velezensis CE 100, and this is the first report about the antifungal activity of 5-nonylamine against C. gloeosporioides. Full article

(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)

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13 pages, 2830 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Copper Stress Enhances the Lignification of Axial Organs in Zinnia elegans

by Anastasia Tugbaeva, Alexander Ermoshin, Hada Wuriyanghan, Maria Maleva, Galina Borisova and Irina Kiseleva

Horticulturae 2022, 8(6), 558; https://doi.org/10.3390/horticulturae8060558 - 20 Jun 2022

Cited by 8 | Viewed by 2613

Abstract

Zinnia elegans Jacq. is an ornamental plant, widely used in landscaping. Heavy-metal pollution in urban and rural areas is still increasing, which determines the actuality of studying plants’ reactions to pollutants. Zinnia was not sufficiently studied in this regard, so the aim of [...] Read more.

Zinnia elegans Jacq. is an ornamental plant, widely used in landscaping. Heavy-metal pollution in urban and rural areas is still increasing, which determines the actuality of studying plants’ reactions to pollutants. Zinnia was not sufficiently studied in this regard, so the aim of our research was to identify morphophysiological changes in this species under excess copper concentration in the soil. For this, we treated a growth substrate with 200 µM CuSO₄ solution for 20 days. At the end of the treatment, several morphological, biochemical, and molecular genetic traits were evaluated: the root and the shoot size; the concentration of H₂O₂ and malondialdehyde (MDA), as indicators of stress; the amount of the phenolic compounds and lignin; and the level of the expression of genes, which encoded their biosynthesis. The Cu amount in the substrate and zinnia organs was quantified using atomic-absorption spectroscopy; hydrogen peroxide, MDA, and phenolic compounds were determined spectrophotometrically, while the amount of lignin was determined according to Klason. Real-time PCR was used for estimation of the gene-transcription level. Lignin in tissues was visualized by fluorescent microscopy. In experimental plants, Cu accumulation was higher in the root than in the stem. This caused an increase in stress markers and a decrease in the root and stem lengths. For the first time for zinnia, it was shown that for several genes—4-coumarate-CoA ligase (4CL), cinnamoyl alcohol dehydrogenase (CAD), and class III peroxidase (PRX)—the level of expression increased under copper treatment. The rise of the transcripts’ amount of these genes was accompanied by a thickening and lignification of the cell walls in the metaxylem vessels. Thus, the adaptation of zinnia to the excess Cu in the growth medium was associated with the metabolic changes in the phenylpropanoid pathway. As a result, the lignification increased in the root, which led to the accumulation of Cu in this organ and limited its translocation through the xylem to the stem, which provided plant growth. Full article

(This article belongs to the Special Issue Horticultural Plants Facing Stressful Conditions - Ways of Stress Mitigation)

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16 pages, 3510 KiB

Open AccessEditor’s ChoiceArticle

Effects of Cold Temperature and Acclimation on Cold Tolerance and Cannabinoid Profiles of Cannabis sativa L. (Hemp)

by Andrei Galic, Heather Grab, Nicholas Kaczmar, Kady Maser, William B. Miller and Lawrence B. Smart

Horticulturae 2022, 8(6), 531; https://doi.org/10.3390/horticulturae8060531 - 15 Jun 2022

Cited by 6 | Viewed by 6687

Abstract

Hemp (Cannabis sativa) is a multi-use crop garnering newfound attention from researchers and consumers. While interest has emerged, a lack of substantiated research still exists regarding effects of adverse weather events on physiological health and secondary metabolite production of hemp. The [...] Read more.

Hemp (Cannabis sativa) is a multi-use crop garnering newfound attention from researchers and consumers. While interest has emerged, a lack of substantiated research still exists regarding effects of adverse weather events on physiological health and secondary metabolite production of hemp. The aim of this experiment was to assess cold tolerance of hemp using the cultivars ‘FINOLA’ and ‘AutoCBD’. Effects of cultivar, plant age, cold acclimation, frequency of cold treatments, and intensity of cold treatments were all considered in regard to their influence on physiological stress, biomass, and cannabinoid profile. Few effects of sequential cold treatments were noted, and they were not moderated by cold acclimation, which tended to have negative effects across many responses. This detrimental effect of cold acclimation conditions was further observed in decreased total CBD % and total THC % compared to non-acclimated plants. These findings bear consideration when assessing the unpredictability of a changing climate’s effects on the heath and cannabinoid profile of hemp. Full article

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

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13 pages, 531 KiB

Open AccessEditor’s ChoiceArticle

Nitrogen Fertigation Rate and Foliar Urea Spray Affect Plant Growth, Nitrogen, and Carbohydrate Compositions of Encore Azalea ‘Chiffon’ Grown in Alternative Containers

by Tongyin Li, Xiaojie Zhao, Guihong Bi, T. Casey Barickman and Richard L. Harkess

Horticulturae 2022, 8(6), 525; https://doi.org/10.3390/horticulturae8060525 - 15 Jun 2022

Cited by 1 | Viewed by 1944

Abstract

The objective of this study was to investigate the plant vegetative growth, flower production, nitrogen (N) concentration, and carbohydrate compositions of Encore^® azalea ‘Chiffon’ when fertigated with five N rates—0, 5, 10, 15, and 20 mM N—and grown in two types of [...] Read more.

The objective of this study was to investigate the plant vegetative growth, flower production, nitrogen (N) concentration, and carbohydrate compositions of Encore^® azalea ‘Chiffon’ when fertigated with five N rates—0, 5, 10, 15, and 20 mM N—and grown in two types of containers, a black plastic and a biodegradable container, during one growing season. Foliar urea of 3% was applied to half of the plants in late fall to investigate its effect on plant N and carbohydrate concentrations. The paper biocontainers resulted in superior plant growth, increased plant size, dry weights, root length and surface area compared with the plastic containers with N rates of 10, 15, and 20 mM. The paper biocontainers also increased N uptake and carbohydrate concentrations mainly by increasing plant biomass. High N rates of 10 to 20 mM combined with urea spray and biocontainers generally resulted in the highest plant N concentrations. Foliar urea application in late fall tended to increase plant N concentration but decreased carbohydrates, including starch, glucose, fructose, and sucrose, to varying degrees, likely due to increased N assimilation. Fall foliar urea spray can be effective in improving the N status of azalea plants without affecting plant biomass. Full article

(This article belongs to the Section Plant Nutrition)

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21 pages, 10698 KiB

Open AccessEditor’s ChoiceArticle

Effect of Covering Crops between Rows on the Vineyard Microclimate, Berry Composition and Wine Sensory Attributes of ‘Cabernet Sauvignon’ (Vitis vinifera L. cv.) Grapes in a Semi-Arid Climate of Northwest China

by Jing Peng, Wei Wei, Hao-Cheng Lu, Wu Chen, Shu-De Li, Jun Wang, Chang-Qing Duan and Fei He

Horticulturae 2022, 8(6), 518; https://doi.org/10.3390/horticulturae8060518 - 13 Jun 2022

Cited by 4 | Viewed by 1942

Abstract

Covering crops was a commonly used viticultural technique to adjust the vineyard microclimate, thus affecting the grape and wine quality. In this two-year study, the purslane (Portulaca oleracea L.) was used to cover the lands between rows in the vineyards located in [...] Read more.

Covering crops was a commonly used viticultural technique to adjust the vineyard microclimate, thus affecting the grape and wine quality. In this two-year study, the purslane (Portulaca oleracea L.) was used to cover the lands between rows in the vineyards located in the semi-arid Northwest China, Xinjiang. Results showed that the photosynthetically active radiation around the fruit zone and the temperature with the purslane covering treatment decreased. Compared with the clean tillage, covering purslane had lower TSS and higher TA in the grape berries, while lower alcohol content and higher TA was also found in their corresponding wines. Covering purslane treatment significantly increased the contents of anthocyanin and flavonol in the grapes and wines in the year 2018, but no significant effect on flavanols was observed in the wines. Norisoprenoids, esters, and C₆ alcohols in the grapes and wines were increased in the purslane covering treatment, respectively. Additionally, compared to the clean tillage, the purslane covering treatment significantly improved the sensory value of the wines, especially the floral aroma and the complexity of the wines. This study helped us to better understand the feasibility of applying covering purslane in viticulture in the semi-arid climate of Northwest China. Full article

(This article belongs to the Special Issue Advances in Berry Crop Flavoromics, Secondary Metabolism and Regulation)

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31 pages, 3506 KiB

Open AccessEditor’s ChoiceReview

Sustainable Management of Diseases in Horticulture: Conventional and New Options

by Marco Scortichini

Horticulturae 2022, 8(6), 517; https://doi.org/10.3390/horticulturae8060517 - 13 Jun 2022

Cited by 11 | Viewed by 6245

Abstract

To reduce the impact of chemical pesticides on the environment, there are relevant efforts to enhance the possibility of controlling plant diseases using environmentally friendly biocontrol agents or natural products that show pathogen control capacity. The European Union, FAO, and the United Nations [...] Read more.

To reduce the impact of chemical pesticides on the environment, there are relevant efforts to enhance the possibility of controlling plant diseases using environmentally friendly biocontrol agents or natural products that show pathogen control capacity. The European Union, FAO, and the United Nations largely promote and finance projects and programs in order to introduce crop protection principles that can attain sustainable agriculture. Preventive measures related to the choice of cultivars, soil fertility, integrated pest management (IPM), and organic farming strategies are still the basis for obtaining satisfactory crop yields and reducing classical pesticide utilisation through the application of commercially available and ecofriendly control agents. Effective pathogen detection at borders to avoid quarantine pathogens is mandatory to reduce the risk of future epidemics. New technical support for the development of sustainable pathogen control is currently being provided by forecasting models, precision farming, nanotechnology, and endotherapy. New biocontrol agents and natural products, disease management through plant nutrition, systemic resistance inducers, and gene-silencing technology will provide solutions for obtaining satisfactory disease control in horticulture. The “multi-stakeholder partnership” strategy can promote the implementation of sustainable crop protection. Full article

(This article belongs to the Special Issue Sustainable Control Strategies of Plant Pathogens in Horticulture)

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13 pages, 1601 KiB

Open AccessEditor’s ChoiceArticle

Effect of Flavonoid Dynamic Changes on Flower Coloration of Tulipa gesneiana ‘Queen of Night’ during Flower Development

by Xueying Guo, Xueqing Fu, Xin Li and Dongqin Tang

Horticulturae 2022, 8(6), 510; https://doi.org/10.3390/horticulturae8060510 - 9 Jun 2022

Cited by 5 | Viewed by 2692

Abstract

Tulipa gesneriana has rich cultivars with abundant flower colors; among them, black tulips have become precious cultivars for their rareness in nature. It is of great significance to understand its color formation mechanism for breeding new cultivars with a blackish flower color in [...] Read more.

Tulipa gesneriana has rich cultivars with abundant flower colors; among them, black tulips have become precious cultivars for their rareness in nature. It is of great significance to understand its color formation mechanism for breeding new cultivars with a blackish flower color in the future. In this present study, petals at five developmental stages of Tulipa gesneriana ‘Queen of Night’ (shorted for ‘QN’), a typical black tulip cultivar, were collected to identity the flavonoid composition and compare the accumulation along with the flower development process, aiming to explore the metabolic mechanism of its flower coloration. By using UPLC-Q-TOF-MS, three anthocyanins and nineteen anthoxanthins (including eighteen flavonols and one flavone) were detected in the petals of ‘QN’. The anthocyanins were identified as delphinidin 3-o-rutinoside, cyanidin 3-o-rutinoside and pelargonidin 3-o-rutinoside, respectively. The main flavonols were identified as quercetin, kaempferol, isorhamnetin, naringin and their glycosides. The only one flavone substance was identified as an apigenin derivative. By comparing the content, anthocyanins were the most abundant substance in the petals of ‘QN’, and showed obvious regularity in the development process. With the flower opening, the anthocyanin content accumulated continuously, and reached the highest level at 3575.9 μg·g⁻¹·FW at S5, accounting for 80% of the total flavonoids. Among them, delphinidin 3-o-rutinoside and cyanidin 3-o-rutinoside made the main contribution to the coloration of ‘QN’. The content of anthoxanthins increased first and then decreased, reaching the highest to 1114.8 μg·g⁻¹·FW at S3. Quercetin and its glycosides were the most important flavonol substances in the petals of ‘QN’, accounting for more than 60% of the total anthoxanthins in the five stages. The content of a flavone identified was extremely low, suggesting a limited role in the flower color of ‘QN’. Taken together, the flower color presentation of ‘QN’ was closely related to the composition and accumulation of anthocyanins and flavonols; anthocyanins were the main substances that determine the petal coloration of ‘QN’, and the high content of flavonols played a role of co-pigmentation with these anthocyanins. Full article

(This article belongs to the Special Issue Advances in Ornamental Plant Cultivation and Physiology)

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12 pages, 1871 KiB

Open AccessEditor’s ChoiceArticle

Gamma Radiation (⁶⁰Co) Induces Mutation during In Vitro Multiplication of Vanilla (Vanilla planifolia Jacks. ex Andrews)

by María Karen Serrano-Fuentes, Fernando Carlos Gómez-Merino, Serafín Cruz-Izquierdo, José Luis Spinoso-Castillo and Jericó Jabín Bello-Bello

Horticulturae 2022, 8(6), 503; https://doi.org/10.3390/horticulturae8060503 - 5 Jun 2022

Cited by 4 | Viewed by 2764

Abstract

In vitro mutagenesis is an alternative to induce genetic variation in vanilla (Vanilla planifolia Jacks. ex Andrews), which is characterized by low genetic diversity. The objective of this study was to induce somaclonal variation in V. planifolia by gamma radiation and detect [...] Read more.

In vitro mutagenesis is an alternative to induce genetic variation in vanilla (Vanilla planifolia Jacks. ex Andrews), which is characterized by low genetic diversity. The objective of this study was to induce somaclonal variation in V. planifolia by gamma radiation and detect it using inter-simple sequence repeat (ISSR) molecular markers. Shoots previously established in vitro were multiplied in Murashige and Skoog culture medium supplemented with 2 mg·L⁻¹ BAP (6-benzylaminopurine). Explants were irradiated with different doses (0, 20, 40, 60, 80 and 100 Gy) of ⁶⁰Co gamma rays. Survival percentage, number of shoots per explant, shoot length, number of leaves per shoot, and lethal dose (LD₅₀) were recorded after 60 d of culture. For molecular analysis, ten shoots were used for each dose and the donor plant as a control. Eight ISSR primers were selected, and 43 fragments were obtained. The percentage of polymorphism (% P) was estimated. A dendrogram based on Jaccard’s coefficient and the neighbor joining clustering method was obtained. Results showed a hormetic effect on the explants, promoting development at low dose (20 Gy) and inhibition and death at high doses (60–100 Gy). The LD₅₀ was observed at the 60 Gy. Primers UBC-808, UBC-836 and UBC-840 showed the highest % P, with 42.6%, 34.7% and 28.7%, respectively. Genetic distance analysis showed that treatments without irradiation and with irradiation presented somaclonal variation. The use of gamma rays during in vitro culture is an alternative to broaden genetic diversity for vanilla breeding. Full article

(This article belongs to the Special Issue The State-of-the-Art Propagation and Breeding Techniques for Horticulture Crops)

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13 pages, 1614 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Fungicides and Application Strategies for the Management of the Red Leaf Blotch Disease of Almond

by Laura Torguet, Lourdes Zazurca, Guillem Martínez, Gemma Pons-Solé, Jordi Luque and Xavier Miarnau

Horticulturae 2022, 8(6), 501; https://doi.org/10.3390/horticulturae8060501 - 4 Jun 2022

Cited by 5 | Viewed by 3037

Abstract

Red leaf blotch (RLB) of almond, caused by Polystigma amygdalinum, is an important foliar disease of this nut tree in the Mediterranean basin and especially in Spain. In recent years, the control of this disease has become a key factor in the [...] Read more.

Red leaf blotch (RLB) of almond, caused by Polystigma amygdalinum, is an important foliar disease of this nut tree in the Mediterranean basin and especially in Spain. In recent years, the control of this disease has become a key factor in the management of Spanish almond orchards. The management of RLB is not easy due to intrinsic factors of the disease (e.g., long infection and latency periods) and the low number of registered fungicides in this country. From 2015 to 2019, different field trials were conducted in the Lleida region, NE Spain, to evaluate the efficacy of several fungicide products and of application strategies to control this disease. Systemic fungicides, which included fluopyram, trifloxystrobin, and mixtures of fluopyram + trifloxystrobin and pyraclostrobin + boscalid, performed better than contact and penetrant products and showed up to 90% control against RLB. However, the efficacy of the tested fungicides varied depending on the year. In terms of application strategies, when fungicide applications were conducted following specific meteorological conditions (after 15 days from >15 mm rainfalls with ≈10–15 °C as the minimum average temperature), their efficacy was comparable to that of calendar-based treatments (every 14, 21, or 31 days from petal fall) but with fewer applications (depending on the year, 2–4 applications as compared with 5–9 for calendar treatments). Full article

(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)

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15 pages, 2362 KiB

Open AccessEditor’s ChoiceArticle

Combined Nano Silver, α-Aminoisobutyric Acid, and 1-Methylcyclopropene Treatment Delays the Senescence of Cut Roses with Different Ethylene Sensitivities

by Suong Tuyet Thi Ha and Byung-Chun In

Horticulturae 2022, 8(6), 482; https://doi.org/10.3390/horticulturae8060482 - 28 May 2022

Cited by 7 | Viewed by 2091

Abstract

Flower senescence varies among cut roses (Rosa hybrida L.), and it is known that the postharvest life of ethylene-sensitive flowers is strongly related to the transcriptional accumulation of ethylene biosynthesis genes, whereas that of ethylene-insensitive flowers is shortened by water stress. These [...] Read more.

Flower senescence varies among cut roses (Rosa hybrida L.), and it is known that the postharvest life of ethylene-sensitive flowers is strongly related to the transcriptional accumulation of ethylene biosynthesis genes, whereas that of ethylene-insensitive flowers is shortened by water stress. These different responses of flowers to hormone and water stresses limit the action of preservatives in inhibiting the postharvest deterioration of cut rose flowers. This study was conducted to investigate the effects of the combined application of antibacterial agents and ethylene biosynthesis and binding inhibitors on the postharvest life and quality of the cut rose cultivars ‘Matador’ (ethylene-sensitive) and ‘Dolcetto’ (ethylene-insensitive). Cut flowers were treated with nano silver (NS), a combination of NS and α-aminoisobutyric acid (NS+A), or a combination of NS+A and 1-methylcyclopropene (NS+AM), and they were subsequently exposed to ethylene for 24 h. Treatment effectiveness was compared with that of control (CON) flowers, which were kept in distilled water and exposed only to ethylene. The results showed that all treatments significantly improved the postharvest quality and vase life of both rose cultivars. However, NS+AM most markedly delayed senescence and prolonged the vase life of cut flowers by 217% in ‘Matador’ and 168.4% in ‘Dolcetto’, compared with those of CON flowers. NS+AM also effectively increased the flower diameter and maintenance time of positive water balance and initial fresh weight by enhancing solution absorption as well as suppressing bacterial growth at the cut stem ends of the cut roses. Furthermore, NS+AM greatly suppressed the ethylene-inducible increase of ethylene biosynthesis genes and the reduction of ethylene receptor genes in petals, which resulted in a reduced flower response to exogenous ethylene in both rose cultivars. These findings show that NS+AM effectively delays flower senescence in both ethylene sensitive and insensitive cultivars by synergistically preventing ethylene response and water stress in cut flowers. Full article

(This article belongs to the Special Issue Factors Affecting Export Flower Quality and Strategies for Prolonging Flowers Vase Life)

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14 pages, 5320 KiB

Open AccessEditor’s ChoiceArticle

Effect of Saline–Alkali Stress on Sugar Metabolism of Jujube Fruit

by Yan Wang, Yifeng Feng, Min Yan, Ju Yu, Xiaofeng Zhou, Jingkai Bao, Qiaoqiao Zhang and Cuiyun Wu

Horticulturae 2022, 8(6), 474; https://doi.org/10.3390/horticulturae8060474 - 26 May 2022

Cited by 4 | Viewed by 1913

Abstract

Sugar, an osmoregulatory substance used by plants to adapt to abiotic stresses such as drought and salinity, is one of the most important indexes of fruit quality. In this study, 0–150 mM saline–alkali solutions (NaCl:NaHCO₃ = 3:1) were used to irrigate the [...] Read more.

Sugar, an osmoregulatory substance used by plants to adapt to abiotic stresses such as drought and salinity, is one of the most important indexes of fruit quality. In this study, 0–150 mM saline–alkali solutions (NaCl:NaHCO₃ = 3:1) were used to irrigate the roots of 10-year-old “Junzao” fruit trees during the growth period to explore the regulation mechanism of different concentrations of saline–alkali stress on sugar and reactive oxygen metabolism in jujube fruit at maturity. The results showed that under low stress (0~90 mM), the contents of sucrose, glucose, and fructose in the jujube fruit and the activities of sucrose phosphate synthase (SPS), sucrose synthase decomposition direction (SS-I), and sucrose synthase synthesis direction (SS-II) increased with increases in stress concentration, results that were consistent with the relative expression trends of the SPS and SS genes; however, the results were reversed under high concentrations (120 and 150 mM). The soluble acid invertase (S-AI) activity decreased with increases in stress concentration under low stress, and the results were reversed with high stress, which was consistent with the relative expression trends of the ZjcINV3, ZjnINV1, and ZjnINV3. Research regarding the response of antioxidant enzymes in fruits under saline–alkali stress showed that only the differences in peroxidase (POD) activity under saline–alkali stress were consistent with sugar accumulation; the proline (PRO), catalase (CAT) decreased and the malondialdehyde (MDA) superoxide dismutase (SOD) increased with increases in saline–alkali stress. These results indicate that the sugar metabolism and antioxidase jointly promote and regulate sugar accumulation in jujube fruits in a low saline–alkali environment. Full article

(This article belongs to the Special Issue Plant Physiology under Abiotic Stresses)

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