Horticulturae

19 pages, 2888 KiB

Open AccessEditor’s ChoiceArticle

Impact of Elevated CO₂ and Temperature on Growth, Development and Nutrient Uptake of Tomato

by Tejaswini C. Rangaswamy, Shankarappa Sridhara, Konapura Nagaraja Manoj, Pradeep Gopakkali, Nandini Ramesh, Shadi Shokralla, Tarek K. Zin El-Abedin, Khalid F. Almutairi and Hosam O. Elansary

Horticulturae 2021, 7(11), 509; https://doi.org/10.3390/horticulturae7110509 - 19 Nov 2021

Cited by 6 | Viewed by 2669

Abstract

Elevated carbon dioxide (EC) can increase the growth and development of different C₃ fruit crops, which may further increase the nutrient demand by the accumulated biomass. In this context, the current investigation was conceptualized to evaluate the growth performance and nutrient uptake [...] Read more.

Elevated carbon dioxide (EC) can increase the growth and development of different C₃ fruit crops, which may further increase the nutrient demand by the accumulated biomass. In this context, the current investigation was conceptualized to evaluate the growth performance and nutrient uptake by tomato plants under elevated CO₂ (EC₇₀₀ and EC₅₅₀ ppm) and temperature (+2 °C) in comparison to ambient conditions. Significant improvement in the growth indicating parameters like leaf area, leaf area index, leaf area duration and crop growth rate were measured at EC₇₀₀ and EC₅₅₀ at different stages of crop growth. Further, broader and thicker leaves of plants under EC₇₀₀ and EC₅₅₀ have intercepted higher radiation by almost 11% more than open field plants. Conversely, elevated temperature (+2 °C) had negative influence on crop growth and intercepted almost 7% lower radiation over plants under ambient conditions. Interestingly, earliness of phenophases viz., branch initiation (3.0 days), flower initiation (4.14 days), fruit initiation (4.07 days) and fruit maturation (7.60 days) were observed at EC₇₀₀ + 2 °C, but it was statistically on par with EC₇₀₀ and EC₅₅₀ + 2 °C. Irrespective of the plant parts and growth stages, plants under EC₇₀₀ and EC₅₅₀ have showed significantly higher nutrient uptake due to higher root biomass. At EC₇₀₀, the tune of increase in total nitrogen, phosphorus and potassium uptake was almost 134%, 126% and 135%, respectively compared to open field crop. This indicates higher nutrient demand by the crop under elevated CO₂ levels because of higher dry matter accumulation and radiation interception. Thus, nutrient application is needed to be monitored at different growth stages as per the crop needs. Full article

(This article belongs to the Special Issue Nutrient Use Efficiency under Optimal and Stressful Conditions of Horticulture Plants)

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11 pages, 6182 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Somatic Embryogenesis in Vitis for Genome Editing: Optimization of Protocols for Recalcitrant Genotypes

by Lucia Rosaria Forleo, Margherita D’Amico, Teodora Basile, Antonio Domenico Marsico, Maria Francesca Cardone, Flavia Angela Maria Maggiolini, Riccardo Velasco and Carlo Bergamini

Horticulturae 2021, 7(11), 511; https://doi.org/10.3390/horticulturae7110511 - 19 Nov 2021

Cited by 5 | Viewed by 2072

Abstract

New Plant Breeding Techniques (NPBTs) protocols have been developed to produce new grape varieties with improved quantitative and qualitative characteristics. Reliable transformation protocols for grapes are based on the generation/induction of embryogenic callus cells that are then transformed. Varieties such as Italia have [...] Read more.

New Plant Breeding Techniques (NPBTs) protocols have been developed to produce new grape varieties with improved quantitative and qualitative characteristics. Reliable transformation protocols for grapes are based on the generation/induction of embryogenic callus cells that are then transformed. Varieties such as Italia have proven to be very recalcitrant to regeneration via somatic embryogenesis. In this work, the development of a protocol for improved production of embryogenic calluses is described. Two sterilization protocols were tested: (a) a lower active chlorine concentration for a longer time (LS); and (b) a higher chlorine concentration for a shorter time (HS), in combination with the absence or presence of citric acid in the growing substrate in the first growth media. The embryogenic calluses formation in Chardonnay, a cv. with a high embryogenic response, was significantly higher in presence of citric acid in the initial growing substrate regardless of the sterilization protocol. In Aglianico, a cv. with a lower embryogenic response, no significant differences were observed. Instead, in a recalcitrant cv. as Italia, we obtained a 13-fold increase in embryogenic calluses formation performing sterilization of flowers with the HS protocol compared to LS. Full article

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

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11 pages, 2953 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Urban Double-Crop: Can Fall Vegetables and a Warm-Season Lawn Co-Exist?

by Ellen M. Bauske, Sheri Dorn, Freddie Clinton Waltz, Jr. and Lauren Garcia Chance

Horticulturae 2021, 7(11), 505; https://doi.org/10.3390/horticulturae7110505 - 18 Nov 2021

Viewed by 1685

Abstract

A gardening methodology using double-cropped cool-season vegetables and warm-season turfgrass, thereby capitalizing on the ideal growing season for each, was developed in field trials and tested in volunteers’ landscapes. Broccoli (Brassica oleracea), lettuce (Lactuca sativa), and Swiss chard ( [...] Read more.

A gardening methodology using double-cropped cool-season vegetables and warm-season turfgrass, thereby capitalizing on the ideal growing season for each, was developed in field trials and tested in volunteers’ landscapes. Broccoli (Brassica oleracea), lettuce (Lactuca sativa), and Swiss chard (Beta vulgaris subsp. Cicla) were planted into an established hybrid bermudagrass lawn (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy ‘Tifsport’) in September. The vegetables were planted into tilled strips, 5 cm × 10 cm holes and 10 cm × 10 cm holes in the turf. All treatments produced harvestable yield, though the yield of vegetables planted in the tilled treatments and larger holes was greater than in smaller holes. Efforts to reduce turfgrass competition with vegetables by the application of glyphosate or the use of the Veggie Lawn Pod (an easily installed plastic cover on the lawn) did not increase yield. Tilled treatments left depressions that discouraged spring turfgrass recovery. The double-crop was tested by seven volunteers on their lawns. Though lawn-planted vegetables did not produce as much yield as those planted in the volunteers’ gardens, the volunteers were enthusiastic about this methodology. The volunteers reported that lawn vegetables were more difficult to plant but not more difficult to maintain, and they were easier to harvest than vegetables in their gardens. All volunteers reported satisfactory recovery of their lawns in the spring. Full article

(This article belongs to the Special Issue Consumer Horticulture Advancement)

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16 pages, 4135 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Effects of Different Fertilization Practices in Combination with the Use of PGPR on the Sugar and Amino Acid Content of Asparagus officinalis

by Nikolaos Xekarfotakis, Theocharis Chatzistathis, Magkdi Mola, Triantafyllia Demirtzoglou and Nikolaos Monokrousos

Horticulturae 2021, 7(11), 507; https://doi.org/10.3390/horticulturae7110507 - 18 Nov 2021

Cited by 5 | Viewed by 2346

Abstract

The present study examined the effects of different nitrogen (NH₄NO₃) and potassium (KNO₃) fertilization levels in combination with a nitrogen-fixing, plant growth-promoting rhizobacteria (PGPR) inoculation on the carbohydrate (CHO), amino acid content, and nutrient concentrations (N, P, [...] Read more.

The present study examined the effects of different nitrogen (NH₄NO₃) and potassium (KNO₃) fertilization levels in combination with a nitrogen-fixing, plant growth-promoting rhizobacteria (PGPR) inoculation on the carbohydrate (CHO), amino acid content, and nutrient concentrations (N, P, K) in the spears and the root system of asparagus plants. No significant differences were indicated between the different fertilization treatments regarding N, P, and K in the leaves and roots of asparagus. The inoculation of the asparagus fields with PGPR, no matter the type of the inorganic fertilizer, resulted in increased CHO and amino acid content of the foliage and roots of asparagus. The highest CHO content and amino acid content were recorded in the treatment that combined PGPR inoculation along with KNO₃ fertilizer, indicating that higher K applications acted synergistically with the added PGPR. Full article

(This article belongs to the Special Issue Nutrient Use Efficiency under Optimal and Stressful Conditions of Horticulture Plants)

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19 pages, 6427 KiB

Open AccessEditor’s ChoiceArticle

Postharvest Treatment of ‘Florida Prince’ Peaches with a Calcium Nanoparticle–Ascorbic Acid Mixture during Cold Storage and Its Effect on Antioxidant Enzyme Activities

by Lo’ay A. A., Hamed Ismail and Hazem S. Kassem

Horticulturae 2021, 7(11), 499; https://doi.org/10.3390/horticulturae7110499 - 15 Nov 2021

Cited by 7 | Viewed by 2309

Abstract

Chilling injury (CI) is a physiological disorder resulting from low storage temperatures that affects the fruit quality and marketing of the ‘Florida Prince’ peach. In this study, the exogenous application of a mixture of calcium nanoparticles (CaNPs) and ascorbic acid was found to [...] Read more.

Chilling injury (CI) is a physiological disorder resulting from low storage temperatures that affects the fruit quality and marketing of the ‘Florida Prince’ peach. In this study, the exogenous application of a mixture of calcium nanoparticles (CaNPs) and ascorbic acid was found to significantly alleviate the symptoms of CI in peaches during cold storage. Fruits were treated with CaNPs plus different concentrations of ascorbic acid (AA; 0, 3, 6, and 9 mM). Peaches were immersed in CaNP–AA for 15 min before being stored at 4 ± 1 °C and 95 ± 1% RH for 30 days. We observed that the 9 mM CaNP–AA treatment lowered the values for the CI index, ion leakage, and malondialdehyde (MDA) content and increased antioxidant enzyme activities (AEAs), such as for ascorbate oxidase (APX), catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR). Furthermore, the treatment reduced the accumulation of both H₂O₂ and O₂^•− and increased the level of DPPH reduction throughout the duration of cold storage. Our results suggest that 9 mM CaNP–AA treatment suppresses the incidence of CI in peach fruit throughout cold storage, possibly because 9 mM CaNP–AA is at least partly involved in enhancing the antioxidant system via its effect on antioxidant substances. The results indicate that applying the 9 mM CaNP–AA treatment afforded peaches with enhanced tolerance against cold storage stress. Full article

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

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11 pages, 5258 KiB

Open AccessEditor’s ChoiceArticle

Somatic Embryogenesis and Indirect In Vitro Plant Regeneration in Amorphophallus konjac K. Koch by One-Step Seedling Formation

by Dandan Li, Mohammad Aqa Mohammadi, Yuan Qin and Zongshen Zhang

Horticulturae 2021, 7(11), 497; https://doi.org/10.3390/horticulturae7110497 - 15 Nov 2021

Cited by 1 | Viewed by 3363

Abstract

Konjac (Amorphophallus konjac K. Koch) is a well-known tuberous vegetable belonging to the important medicinal family Araceae, and the plant grows from an underground tuber. Here, we used a “one-step seedling regeneration” tissue culture system to improve the plantlet regeneration efficiency [...] Read more.

Konjac (Amorphophallus konjac K. Koch) is a well-known tuberous vegetable belonging to the important medicinal family Araceae, and the plant grows from an underground tuber. Here, we used a “one-step seedling regeneration” tissue culture system to improve the plantlet regeneration efficiency of konjac using young leaves as an explant source. In the current study, we used several sterilization methods for tuber sterilization. Moreover, various plant growth regulator combinations were applied to achieve efficient somatic embryogenesis and plantlet regeneration. Our results showed that the optimal tuber sterilization was method C (75% alcohol for 15 s + 0.1% HgCl₂ for 15 min + washing by double-sterilized water three times). Three types of embryogenic calli were induced on full-strength Murashige and Skoog (MS) basal medium supplemented with 0.5 mg/L of 6-benzylaminopurine (6-BA), 0.5 mg/L of naphthaleneacetic acid (NAA), 1.0 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D), and 30 g/L of sucrose. Of the three types of embryogenic calli, only type Ⅲ further regenerated plantlets, with a callus induction rate of 55.73% and a seedling induction rate of 92.73%. This suggests that the addition of the above hormones gives the optimal callus induction. The proliferation rate achieved was 38% on the MS basal medium containing 1.0 mg/L of 6-BA, 1.0 mg/L of indolebutyric acid (IBA), 0.2 mg/L of kinetin (KT), and 50 g/L of sucrose. The one-step seedling formation achieved in MS medium contained 2.0 mg/L of 6-BA, 0.5 mg/L of NAA, 0.1 mg/L of gibberellic acid (GA₃), and 30 g/L of sucrose, and the number of regenerated shoots per explants was 6 ± 2. Therefore, we establish a one-step seedling regeneration system through indirect plant regeneration, which shortens the time for konjac in vitro regeneration, significantly increased the micropropagation efficiency, and decreased the cost of the konjac tissue culture. Full article

(This article belongs to the Special Issue Metabolic Engineering or Tissue Culture Technology for Medicinal and Horticultural Plants)

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11 pages, 4896 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Selenium Enrichment of Green and Red Lettuce and the Induction of Radical Scavenging Potential

by Muna Ali Abdalla, Jürgen E. Wick, Ibukun M. Famuyide, Lyndy J. McGaw and Karl H. Mühling

Horticulturae 2021, 7(11), 488; https://doi.org/10.3390/horticulturae7110488 - 11 Nov 2021

Cited by 8 | Viewed by 2204

Abstract

Selenium (Se)-enriched vegetables are promising dietary sources of Se, which provides beneficial biological effects in humans. In this study, we investigated the effects of foliar application of Se on hydroponically grown multi-leaf green (V1) and red (V2) lettuce plants. Three selenate (SeIV) amendment [...] Read more.

Selenium (Se)-enriched vegetables are promising dietary sources of Se, which provides beneficial biological effects in humans. In this study, we investigated the effects of foliar application of Se on hydroponically grown multi-leaf green (V1) and red (V2) lettuce plants. Three selenate (SeIV) amendment levels were evaluated for their influence on plant growth, elemental composition and radical scavenging capacity. Lettuce heads biofortified with 0.598 mg Se plant⁻¹ accumulated 19.6–23.6 and 14.9–17.6 μg Se g⁻¹ DM in the multi-leaf green (V1) and red (V2) lettuce plants, respectively. The accumulated Se levels can contribute significantly to the recommended dietary allowance of 70 µg day⁻¹ for adult men and 60 µg day⁻¹ for adult women. Accordingly, both V1 and V2 lettuce cultivars grown under the Se3 foliar application condition can cover the daily requirement for adult men by approximately 100% and 85% to 100%, respectively, by consuming 75–90 g or 100 g fresh weight from V1 or V2, respectively. The ABTS radical scavenging potential of green lettuce was induced at Se2 and Se3 foliar application levels, where the IC₅₀ was 1.124 ± 0.09 μg mL⁻¹ at Se0 and improved to 0.795 ± 0.03 and 0.697 ± 0.01 μg mL⁻¹, respectively. There was no cytotoxicity against Vero kidney cells among all treated lettuce plants at the highest concentration tested of 1 mg/mL. Finally, a further focused investigation of the metabolic profile of lettuce plants under varied Se levels needs to be investigated in future studies. Full article

(This article belongs to the Special Issue Impact of Plant Nutrition on Primary and Secondary Metabolites)

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12 pages, 2426 KiB

Open AccessEditor’s ChoiceArticle

Effects of Berry Thinning on the Physicochemical, Aromatic, and Sensory Properties of Shine Muscat Grapes

by Kyeong-Ok Choi, Dongjun Im, Seo Jun Park, Dong Hoon Lee, Su Jin Kim and Youn Young Hur

Horticulturae 2021, 7(11), 487; https://doi.org/10.3390/horticulturae7110487 - 11 Nov 2021

Cited by 11 | Viewed by 5119

Abstract

The effects of the level of berry thinning (30% and 50% berry removal) on the quality and sensory properties of Shine Muscat grapes were investigated. As berry thinning increased, the total soluble solids content increased and titratable acidity decreased. Berry thinning increased berry [...] Read more.

The effects of the level of berry thinning (30% and 50% berry removal) on the quality and sensory properties of Shine Muscat grapes were investigated. As berry thinning increased, the total soluble solids content increased and titratable acidity decreased. Berry thinning increased berry size and cluster weight but caused no change in individual berry weight. Phenolic concentrations as measured by total phenolic, proanthocyanidin, and polymeric tannin concentrations tended to increase with an increase in berry thinning. Gas chromatographic analysis indicated that C6-compounds were the significant constituents of volatile alcohols and aldehydes; linalool was the most abundant monoterpene. Odor activity analysis indicated that (E)-2-hexen-1-ol, (E)-2-hexenal, 1-hexanal, (Z)-3-hexenal, (E)-β-damascenone, linalool, and (E)-linalool oxide were active odorants. Berry thinning increased the accumulation of linalool contributing to high sensory flavor scores in thinned berries. Furthermore, its oxidized derivative-linalool oxide-contributed to enhancing the Muscat flavor. In conclusion, berry thinning induced compositional changes in Shine Muscat grape berries by accelerating the ripening rate, contribution to improved sensory properties. Full article

(This article belongs to the Section Viticulture)

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17 pages, 13231 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Seed Micromorphology, In Vitro Germination, and Early-Stage Seedling Morphological Traits of Cattleya purpurata (Lindl. & Paxton) Van den Berg

by Miriam Bazzicalupo, Jacopo Calevo, Martino Adamo, Annalisa Giovannini, Andrea Copetta and Laura Cornara

Horticulturae 2021, 7(11), 480; https://doi.org/10.3390/horticulturae7110480 - 10 Nov 2021

Cited by 5 | Viewed by 2670

Abstract

In the context of a symbiotic plant-fungus interaction study concerning Cattleya purpurata, we focused on some aspects of seed morphology and biology, and the early stages of seedling development. Seed morphology was characterized using light and scanning electron microscopy. In vitro seed [...] Read more.

In the context of a symbiotic plant-fungus interaction study concerning Cattleya purpurata, we focused on some aspects of seed morphology and biology, and the early stages of seedling development. Seed morphology was characterized using light and scanning electron microscopy. In vitro seed germination capability was evaluated, comparing symbiotic and asymbiotic methods. The morphology of the seeds was overall comparable to that of other congeneric species, showing classical adaptations related to the aerodynamic properties and to the wettability of seeds, but calcium oxalate druses were identified inside the suspensor cells. Asymbiotic seed germination was successful in all tested media (17.1–46.5%) but was higher on 1/2 Murashige & Skoog. During symbiotic interaction with the fungal strain MUT4178 (Tulasnella calospora), germination rate was significantly lower than that obtained with the best three asymbiotic media, suggesting a low fungal compatibility. Seedling morphology was in line with other taxa from the same genus, showing typical characteristics of epiphytic species. Our observations, in particular, highlighted the presence of stomata with C-shaped guard cells in the leaves, rarely found in Cattleyas (where usually they are reniform), and confirm the presence of tilosomes in the roots. Idioblasts containing raphides were observed in both roots and leaves. Full article

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

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24 pages, 8066 KiB

Open AccessEditor’s ChoiceArticle

Effects of Temperature and Photoperiod on the Flower Potential in Everbearing Strawberry as Evaluated by Meristem Dissection

by Samia Samad, Denis Butare, Salla Marttila, Anita Sønsteby and Sammar Khalil

Horticulturae 2021, 7(11), 484; https://doi.org/10.3390/horticulturae7110484 - 10 Nov 2021

Cited by 7 | Viewed by 3100

Abstract

The growing interest in using everbearing (EB) strawberry cultivars to extend the cultivation period has faced some challenges. These include poor runner production due to its perpetual flowering nature; irregular flowering behavior and extended periods of high temperature have caused floral inhibition and [...] Read more.

The growing interest in using everbearing (EB) strawberry cultivars to extend the cultivation period has faced some challenges. These include poor runner production due to its perpetual flowering nature; irregular flowering behavior and extended periods of high temperature have caused floral inhibition and reduced yield. As flowering is an interplay between temperature and photoperiod, it is important to investigate the effects of this interaction on the cultivation. Therefore, this study used meristem dissection as a tool to study the effect of temperature and photoperiod on meristem development. Tray plants of two EB strawberry cultivars ‘Florentina’ and ‘Favori’ were grown at 20 °C, 25 °C, and 30 °C under short day (SD) conditions, and subsequently at 20 °C under long day (LD) conditions. The meristem development was analysed every 6 weeks for a 15-week period in SD and for 14 weeks in LD conditions using meristem dissection. The plants showed similar flowering patterns to previously studied everbearing cultivars, which was qualitative LD plants at high temperatures and quantitative LD plants at lower temperatures. Our results show that meristem dissection can be used to determine the temperature and photoperiodic effect on meristem development, and for the occurrence of cropping peaks, and can therefore be used to decide the environmental input and to evaluate yield potential. Full article

(This article belongs to the Collection New Challenges in Productivity of Berry Fruits)

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18 pages, 3089 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Application of Rosemary and Eucalyptus Essential Oils and Their Main Component on the Preservation of Apple and Pear Fruits

by Panayiota Xylia, Antonios Chrysargyris, Zienab F. R. Ahmed and Nikolaos Tzortzakis

Horticulturae 2021, 7(11), 479; https://doi.org/10.3390/horticulturae7110479 - 09 Nov 2021

Cited by 31 | Viewed by 3341

Abstract

Nowadays, increase fruit losses are being reported due to the development of fungal postharvest diseases. In an attempt to reduce the use of synthetic fungicides, a turn towards natural products such as essential oils (EOs) and natural compounds has been made. The objective [...] Read more.

Nowadays, increase fruit losses are being reported due to the development of fungal postharvest diseases. In an attempt to reduce the use of synthetic fungicides, a turn towards natural products such as essential oils (EOs) and natural compounds has been made. The objective of this study was to investigate the effects of eucalyptus (Euc), rosemary (Ros) EO, their mixture (50:50 v/v) and their common main component (i.e., eucalyptol) on the quality parameters, fruit response and inhibition of blue rot (Penicillium expansum) in apple and pear fruits during their shelf life. The results of the present study revealed that fungal colony growth decreased in vitro with exposure at eucalyptus EO (Euc-300 μL/L), rosemary EO (Ros-300 μL/L) and their mixture (Euc + Ros 100 and 300 μL/L). The exposure at Ros-100 μL/L stimulated spore production, whilst Euc + Ros (100 and 300 μL/L) and eucalyptol (100 and 300 μL/L) decreased spore germination. Moreover, the in vivo applied treatments resulted in decreased lesion growth of P. expansum in apple and pear fruits. Respiration rate increased with the application of Euc + Ros at 300 μL/L and eucalyptus EO (Euc-100 μL/L and Euc-300 μL/L) for both assessed fruits. On the other hand, no significant differences were reported on apples and pears total soluble solids and acidity values. The application of Euc + Ros-300 μL/L in apples increased hydrogen peroxide (H₂O₂) levels, whilst Euc-100 and Euc-300 μL/L increased lipid peroxidation levels. Regarding pear fruits, exposure to Euc-100 μL/L and Ros-100 μL/L resulted in increased H₂O₂ whereas, Euc-100 μL/L, Ros- (100 and 300 μL/L) and eucalyptol (100 and 300 μL/L) also increased lipid peroxidation. The findings of this study indicate that the investigated natural products can be explored for the preservation of fresh apples and pears, as alternative natural fungicides with consideration of the fresh produce quality attributes. Full article

(This article belongs to the Special Issue Biological Control of Pre- and Postharvest Fungal Diseases)

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11 pages, 614 KiB

Open AccessEditor’s ChoiceArticle

Screening of Amaranthus sp. Varieties for Resistance to Bacterial Wilt Caused by Ralstonia solanacearum

by Rachidatou Sikirou, Marie Epiphane Dossoumou, Judith Honfoga, Victor Afari-Sefa, Ramasamy Srinivasan, Mathews Paret and Wubetu Bihon

Horticulturae 2021, 7(11), 465; https://doi.org/10.3390/horticulturae7110465 - 04 Nov 2021

Cited by 2 | Viewed by 2109

Abstract

Bacterial wilt, caused by Ralstonia solanacearum, is an emerging constraint in amaranth production in Benin. Host resistance is the most sustainable disease control measure. Ten amaranth varieties including A2002, Bresil (B) -Sel, Madiira 2, AC-NL, GARE ES13-7, Madiira 1, UG-AMES13-2, AM-NKGN, IP-5-Sel [...] Read more.

Bacterial wilt, caused by Ralstonia solanacearum, is an emerging constraint in amaranth production in Benin. Host resistance is the most sustainable disease control measure. Ten amaranth varieties including A2002, Bresil (B) -Sel, Madiira 2, AC-NL, GARE ES13-7, Madiira 1, UG-AMES13-2, AM-NKGN, IP-5-Sel and a local variety from Benin were screened for resistance to bacterial wilt. The study was conducted in a screen house and in the naturally contaminated open field during a consecutive rainy and dry season using a randomized complete block design with four and three replications, respectively. In the screen house, plants were inoculated by drenching a 40 mL of bacterial suspension containing 10⁸ CFU/mL of R. solanacearum strain NCBI 5 GenBank N° MH397250 at the collar region. The bacterial wilt incidence (BWI) and the area under the disease progress curve (AUDPC) suggested differential reactions of amaranth varieties to the pathogen. BWI and AUDPC were low for UG-AMES13-2, moderate for Madiira 2, AM-NKGN and the local variety and very high for A2002, Bresil (B) -Sel, AC-NL, GARE ES13-7, Madiira 1 and IP-5-Sel. The World Vegetable Center’s UG-AMES13-2 can be considered as first choice, which is resistant to R. solanacearum, and should be scaled up for seed production towards supporting farmers. Full article

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

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16 pages, 1830 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Molecular Insights into the Effects of Rootstocks on Maturation of Blood Oranges

by Giuseppe Lana, Giulia Modica, Giuseppina Las Casas, Laura Siracusa, Stefano La Malfa, Alessandra Gentile, Angelo Sicilia, Gaetano Distefano and Alberto Continella

Horticulturae 2021, 7(11), 468; https://doi.org/10.3390/horticulturae7110468 - 04 Nov 2021

Cited by 14 | Viewed by 2258

Abstract

Rootstock choice has important effects on the horticultural and pathological traits of the citrus cultivars. Thus, the scion/rootstock combination can affect tree vigour, nutrition, and stress resistance; it can also have positive influences on the fruit quality traits. Although the study of rootstock [...] Read more.

Rootstock choice has important effects on the horticultural and pathological traits of the citrus cultivars. Thus, the scion/rootstock combination can affect tree vigour, nutrition, and stress resistance; it can also have positive influences on the fruit quality traits. Although the study of rootstock effects has been a relevant research topic in citrus for many years, the main body of such study has been conducted at the biochemical level, while little effort has been directed to the determination of the rootstock influences at the molecular level. A comparative study of three combinations of scion and rootstock shows a positive correlation between the regulation of the fruit quality-related genes and the accumulations of bioactive compounds, as well as with acid degradation. Monitoring the anthocyanin accumulation during ripening shows the scion/rootstock combination can increase anthocyanin synthesis in the fruit, as well as vitamin C accumulation and acid degradation. Our results show that the rootstock genotype can exert important influences on citrus fruit quality by affecting gene expression in the scion. New insights into the molecular interactions between scion and rootstock may help unravel the systems through which rootstocks exert their influences on the regulatory networks in the scion, so as to influence relevant agronomic traits. This information should result in an improved rootstock breeding selection and definition of scion/rootstock combinations to enhance fruit quality traits. Full article

(This article belongs to the Special Issue Transcriptional Regulation during Fruit Development and Ripening)

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14 pages, 2209 KiB

Open AccessEditor’s ChoiceArticle

Differential Triggering of the Phenylpropanoid Biosynthetic Pathway Key Genes Transcription upon Cold Stress and Viral Infection in Tomato Leaves

by Polyxeni Pappi, Nikolaos Nikoloudakis, Dimitrios Fanourakis, Antonios Zambounis, Costas Delis and Georgios Tsaniklidis

Horticulturae 2021, 7(11), 448; https://doi.org/10.3390/horticulturae7110448 - 02 Nov 2021

Cited by 16 | Viewed by 2421

Abstract

Plants develop a plethora of defense strategies during their acclimation and interactions with various environmental stresses. Secondary metabolites play a pivotal role in the processes during stress acclimation, therefore deciphering their relevant responses exchange the interpretation of the underlying molecular mechanisms that may [...] Read more.

Plants develop a plethora of defense strategies during their acclimation and interactions with various environmental stresses. Secondary metabolites play a pivotal role in the processes during stress acclimation, therefore deciphering their relevant responses exchange the interpretation of the underlying molecular mechanisms that may contribute to improved adaptability and efficacy. In the current study, tomato plants were exposed to short-term cold stress (5 °C for 16 h) or inoculated (20 d) with either Cucumber Mosaic Virus (CMV) or Potato Virus Y (PVY). Responses were recorded via the assessments of leaf total phenolic (TP) content, total flavonoid (TF) levels, and phenylalanine ammonia-lyase (PAL) enzyme activity. The transcription of the gene families regulating the core phenylpropanoid biosynthetic pathway (PBP) at an early (PAL, cinnamic acid 4-hydroxylase, 4-coumarate-CoA ligase) or late (chalcone synthase and flavonol synthase) stage was also evaluated. The results showed that cold stress stimulated an increase in TP and TF contents, while PAL enzyme activity was also elevated compared to viral infection. Besides genes transcription of the enzymes involved in the core PBP was mostly induced by cold stress, whereas transcription of the genes regulating flavonoid biosynthesis was mainly triggered by viral infection. In conclusion, abiotic and biotic stressors induced differential regulation of the core PBP and flavonoid biosynthetic metabolism. Taking the above into consideration, our results highlight the complexity of tomato responses to diverse stimuli allowing for better elucidation of stress tolerance mechanisms at this crop. Full article

(This article belongs to the Special Issue Stress Biology of Horticultural Plants)

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14 pages, 1266 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Persistence and Transfer of Foodborne Pathogens to Sunflower and Pea Shoot Microgreens during Production in Soil-Free Cultivation Matrix

by Wenjun Deng, Gina M. Misra, Christopher A. Baker and Kristen E. Gibson

Horticulturae 2021, 7(11), 446; https://doi.org/10.3390/horticulturae7110446 - 02 Nov 2021

Cited by 8 | Viewed by 2947

Abstract

Microgreens are an emerging salad crop with properties similar to those of sprouted seeds and lettuce. This study aimed to determine bacterial pathogen persistence during microgreen cultivation and transfer from soil-free cultivation matrix (SFCM) to mature microgreens. Salmonella enterica subsp. enterica ser. Javiana [...] Read more.

Microgreens are an emerging salad crop with properties similar to those of sprouted seeds and lettuce. This study aimed to determine bacterial pathogen persistence during microgreen cultivation and transfer from soil-free cultivation matrix (SFCM) to mature microgreens. Salmonella enterica subsp. enterica ser. Javiana and Listeria monocytogenes were inoculated onto biostrate mats as well as peat SFCM and sampled (day 0). Next, sunflower and pea shoot seeds were planted (day 0) and grown in a controlled environment until the microgreen harvest (day 10). On day 10, SFCM and microgreens were sampled to determine the pathogen levels in the SFCM and the pathogen transfer to microgreens during production. Salmonella Javiana log CFU/g were significantly higher than L. monocytogenes in SFCM on day 10 in both planted and unplanted regions (p < 0.05). Significant differences in pathogen transfer (log CFU/g) were observed between the pea shoot and sunflower microgreens, regardless of the pathogen or SFCM type (p < 0.05). Meanwhile, pathogen transfer to the pea shoot and sunflower microgreens from the biostrate was 1.53 (95% CI: −0.75–3.81) and 5.29 (95% CI: 3.01–7.57) mean log CFU/g, respectively, and transfer from the peat was 0.00 (95% CI: −2.28–2.28) and 2.64 (95% CI: 0.36–4.92) mean log CFU/g, respectively. Results demonstrate that pathogen transfer to microgreens during production is influenced by SFCM and microgreen variety. Full article

(This article belongs to the Special Issue Pathogen Control Strategies for Pre-/Post-harvest of Horticultural Plants and the Application of the Plant-Derived Substances for Microbial Risk Management)

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12 pages, 693 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Shading Nets on Yield, Leaf Biomass and Petiole Nutrients of a Muscat of Alexandria Vineyard Growing under Hyper-Arid Conditions

by Emilio Villalobos-Soublett, Gastón Gutiérrez-Gamboa, Claudio Balbontín, Andrés Zurita-Silva, Antonio Ibacache and Nicolás Verdugo-Vásquez

Horticulturae 2021, 7(11), 445; https://doi.org/10.3390/horticulturae7110445 - 02 Nov 2021

Cited by 6 | Viewed by 2148

Abstract

Background: Currently, viticulture is exposed to extreme weather fluctuations and global warming, thus the implementation of short-term adaptation strategies to mitigate climate change impacts will be of a wide importance for the sustainability and competitiveness of wine industry. This research aimed to [...] Read more.

Background: Currently, viticulture is exposed to extreme weather fluctuations and global warming, thus the implementation of short-term adaptation strategies to mitigate climate change impacts will be of a wide importance for the sustainability and competitiveness of wine industry. This research aimed to study the effect of shading nets on the viticultural performance of a Muscat of Alexandria vineyard growing under hyper-arid conditions. Methods: Three treatments were randomly arranged in the vineyard: (i) a control (without shading), (ii) a white shading net (25% of shading), and (iii) a black shading net (40% of shading). Subsequently, yield, vine vigor, berry composition, leaf biomass and petiole nutrient content were assessed. Results: Both shading nets decreased the incidence of solar radiation in vines. The application of white shading nets induced a high bunch weight and a higher number of berries per bunch than the black shading nets. Black shading nets increased pruning weight, decreased Ravaz index and induced a considerably accumulation of soluble solids in grapes. This treatment also decreased bunch weight and the number of berries per bunch, and increased rachis length compared to control. Black shading nets decreased Mg petiole content, leaf dry weight and leaf biomass at flowering compared to uncovered vines. Conclusions: Shading considerably affected the viticultural performance of Muscat of Alexandria vines growing under hyper-arid conditions, modifying yield, leaf biomass and petiole nutrients. Full article

(This article belongs to the Section Viticulture)

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13 pages, 569 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Sap Analysis: A Powerful Tool for Monitoring Plant Nutrition

by Eduardo Esteves, Guilherme Locatelli, Neus Alcon Bou and Rhuanito Soranz Ferrarezi

Horticulturae 2021, 7(11), 426; https://doi.org/10.3390/horticulturae7110426 - 22 Oct 2021

Cited by 10 | Viewed by 11298

Abstract

Horticultural crop production is moving towards an era of higher nutrient use efficiency since nutrient deficiencies can reduce plant growth, productivity, and quality, and overfertilization can cause environmental pollution. Rapid nutrient concentration diagnostic is essential to minimize the negative effects of Huanglongbing (HLB) [...] Read more.

Horticultural crop production is moving towards an era of higher nutrient use efficiency since nutrient deficiencies can reduce plant growth, productivity, and quality, and overfertilization can cause environmental pollution. Rapid nutrient concentration diagnostic is essential to minimize the negative effects of Huanglongbing (HLB) or citrus greening in citrus by providing the required nutrients before deficiency symptoms appear, reducing the impact of the disease on crop production. Sap analysis is an additional tool for fine-tuning nutrient applications in citrus. The main objective of this paper is to review the different methodologies and results obtained with sap analysis, considering its potential application in citrus production. Results from other crops show the pros and cons of using this tool. Substantial research has been conducted on vegetables and greenhouse crops, but few studies are available on perennial species such as citrus. Inconsistency in the extraction and analysis methods and the lack of specific sufficiency ranges for citrus open the path for further studies. Along with soil and leaf analyses, sap analysis is a complementary technique that can improve nutrient use efficiency in citrus production. Moreover, sap analysis has the potential to optimize fertilizer application, minimize environmental impacts and improve sustainability. Full article

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

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21 pages, 4406 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Impact of the Hydroponic Cropping System on Growth, Yield, and Nutrition of a Greek Sweet Onion (Allium cepa L.) Landrace

by Christos Mouroutoglou, Anastasios Kotsiras, Georgia Ntatsi and Dimitrios Savvas

Horticulturae 2021, 7(11), 432; https://doi.org/10.3390/horticulturae7110432 - 22 Oct 2021

Cited by 6 | Viewed by 6946

Abstract

Nerokremmydo of Zakynthos, a Greek landrace of sweet onion producing a large bulb, was experimentally cultivated in a glasshouse using aeroponic, floating, nutrient film technique, and aggregate systems, i.e., AER, FL, NFT, and AG, respectively. The aim of the experiment was to compare [...] Read more.

Nerokremmydo of Zakynthos, a Greek landrace of sweet onion producing a large bulb, was experimentally cultivated in a glasshouse using aeroponic, floating, nutrient film technique, and aggregate systems, i.e., AER, FL, NFT, and AG, respectively. The aim of the experiment was to compare the effects of these soilless culture systems (SCSs) on plant characteristics, including fresh and dry weight, bulb geometry, water use efficiency, tissue macronutrient concentrations, and uptake concentrations (UC), i.e., uptake ratios between macronutrients and water, during the main growth, bulbing, and maturation stages, i.e., 31, 62, and 95 days after transplanting. The plants grown in FL and AG yielded 7.87 and 7.57 kg m⁻², respectively, followed by those grown in AER (6.22 kg m⁻²), while those grown in NFT produced the lowest yield (5.20 kg m⁻²). The volume of nutrient solution (NS) consumed per plant averaged 16.87 L, with NFT plants recording the least consumption. The SCS affected growth rate of new roots and “root mat” density that led to corresponding nutrient uptake differences. In NFT, reduced nutrient uptake was accompanied by reduced water consumption. The SCS and growth stage strongly affected tissue N, P, K, Ca, Mg, and S mineral concentrations and the respective UC. The UC of N and Κ followed a decreasing trend, while that of Mg decreased only until bulbing, and the UC of the remainder of the macronutrients increased slightly during the cropping period. The UC can be used as a sound basis to establish NS recommendations for cultivation of this sweet onion variety in closed SCSs. Full article

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

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12 pages, 3998 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Light-Independent Anthocyanin Accumulation in Mango (Mangifera indica L.)

by Bin Shi, Hongxia Wu, Bin Zheng, Minjie Qian, Aiping Gao and Kaibing Zhou

Horticulturae 2021, 7(11), 423; https://doi.org/10.3390/horticulturae7110423 - 21 Oct 2021

Cited by 13 | Viewed by 2818

Abstract

Light dependent anthocyanin accumulation contributes to the red pigmentation of the fruit skin of mango (Mangifera indica L.). Light-independent pigmentation has also been reported, but remains poorly characterized. In this study, the pigmentation patterns in the skin of two red mango cultivars, [...] Read more.

Light dependent anthocyanin accumulation contributes to the red pigmentation of the fruit skin of mango (Mangifera indica L.). Light-independent pigmentation has also been reported, but remains poorly characterized. In this study, the pigmentation patterns in the skin of two red mango cultivars, ‘Ruby’ and ‘Sensation’, were evaluated. Metabolomic profiling revealed that quercetin-3-O-glucoside, cyanidin-3-O-galactoside, procyanidin B1, and procyanidin B3 are the predominant flavonoid compounds in the skin of ‘Ruby’ and ‘Sensation’ fruit. Young fruit skin mainly accumulates flavonol and proanthocyanidin, while anthocyanin is mainly accumulated in the skin of mature fruit. Bagging treatment inhibited the biosynthesis of flovonol and anthocyanin, but promoted the accumulation of proanthocyanidin. Compared with ‘Sensation’, matured ‘Ruby’ fruit skin showed light red pigmentation at 120 days after full bloom (DAFB), showing a light-independent anthocyanin accumulation pattern. However, the increase of anthocyanin concentration, and the expression of key anthocyanin structural and regulatory genes MiUFGT1, MiUFGT3, and MiMYB1 in the skin of bagged ‘Ruby’ fruit versus ‘Sensation’ at 120 DAFB was very limited. There was no mutation in the crucial elements of MiMYB1 promoter between ‘Ruby’ and ‘Sensation’. We hypothesize that the light-independent anthocyanin accumulation in the skin of mature ‘Ruby’ fruit is regulated by plant hormones, and that ‘Ruby’ can be used for breeding of new more easily pigmented red mango cultivars. Full article

(This article belongs to the Special Issue Physiology and Molecular Biology of Flowering, Fruit Setting, Fruit Quality)

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11 pages, 2507 KiB

Open AccessEditor’s ChoiceArticle

Water Stress in Dwarfing Cherry Rootstocks: Increased Carbon Partitioning to Roots Facilitates Improved Tolerance of Drought

by Will Wheeler, Brent Black and Bruce Bugbee

Horticulturae 2021, 7(11), 424; https://doi.org/10.3390/horticulturae7110424 - 21 Oct 2021

Cited by 3 | Viewed by 1590

Abstract

Cherry orchards are transitioning to high-density plantings and dwarfing rootstocks to maximize production, but the response of these rootstocks to drought stress is poorly characterized. We used a 16-container, automated lysimeter system to apply repeated water stress to ungrafted Krymsk^® 5 and [...] Read more.

Cherry orchards are transitioning to high-density plantings and dwarfing rootstocks to maximize production, but the response of these rootstocks to drought stress is poorly characterized. We used a 16-container, automated lysimeter system to apply repeated water stress to ungrafted Krymsk^® 5 and 6 rootstocks during two growing cycles. Drought stress was imposed by withholding irrigation until the daily transpiration rate of each tree was 25% and 30% of the unstressed rate during the first trial and second trial, respectively. After this point was reached, the root-zone water status was restored to field capacity. Whole-tree transpiration measurements were supplemented with leaf-level gas-exchange measurements. Krymsk^® 6 had a higher rate of photosynthesis, more vigorous vegetative growth and less conservative stomatal regulation during incipient drought than Krymsk^® 5. At harvest, carbon partitioning to roots was greater in Krymsk^® 6 than Krymsk^® 5. The conservative rate of water use in Krymsk^® 5 could be a function of greater stomatal control or reduced carbon partitioning to roots, which thereby limited transpiration rates. Further studies are needed to confirm that these results are applicable to trees grown using a common grafted scion under field conditions. Full article

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14 pages, 1770 KiB

Open AccessEditor’s ChoiceArticle

Impact of Drought and Flooding on Alkaloid Production in Annona crassiflora Mart

by Ana Beatriz Marques Honório, Iván De-la-Cruz-Chacón, Mariano Martínez-Vázquez, Magali Ribeiro da Silva, Felipe Girotto Campos, Bruna Cavinatti Martin, Gustavo Cabral da Silva, Carmen Sílvia Fernandes Boaro and Gisela Ferreira

Horticulturae 2021, 7(10), 414; https://doi.org/10.3390/horticulturae7100414 - 19 Oct 2021

Cited by 8 | Viewed by 2398

Abstract

The Brazilian Cerrado is the second largest Brazilian biome. In recent decades, a reduction in rainfall has indicated an extension of the dry season. Among the many native species of the Cerrado of the Annonaceae family and used in folk medicine, Annona crassiflora [...] Read more.

The Brazilian Cerrado is the second largest Brazilian biome. In recent decades, a reduction in rainfall has indicated an extension of the dry season. Among the many native species of the Cerrado of the Annonaceae family and used in folk medicine, Annona crassiflora Mart. has fruits of high nutritional value and its by-products are sources of bioactive compounds, such as alkaloids. The aim of the study was to investigate how water stress impacts the production of alkaloids. The study was carried out in a nursery, and the knowledge was flood, field capacity and drought. Gas exchange, chlorophyll a fluorescence, antioxidant enzymes, total soluble sugars, starch, reducing sugars, sucrose, total alkaloids and liriodenine were analyzed. We observed that plants subjected to drought had an increase in the production of total alkaloids and liriodenine, without a reduction in photosynthetic metabolism. Plants kept under drought and flood conditions dissipated higher peroxidase activity, while catalase was higher in flooded plants. Starch showed the highest concentration in flooding plants without differing from drought plants; the lowest trehalose concentrations were found in both drought and flooding plants. The drought stimulated the synthesis of total alkaloids and liriodenine without reducing the primary metabolism, which suggests adaptation to Cerrado conditions. Full article

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

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25 pages, 850 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Moringa oleifera Lam.: A Phytochemical and Pharmacological Overview

by Attilio Anzano, Mohammad Ammar, Marina Papaianni, Laura Grauso, Mohammed Sabbah, Rosanna Capparelli and Virginia Lanzotti

Horticulturae 2021, 7(10), 409; https://doi.org/10.3390/horticulturae7100409 - 16 Oct 2021

Cited by 9 | Viewed by 11424

Abstract

Moringa oleifera Lam. is a fast-growing and drought-resistant tree of the Moringaceae family. The tree is known with some common names: miracle, ben oil, drumstick, horseradish or simply moringa. The plant grows in a variety of environments including harsh conditions. The plant has [...] Read more.

Moringa oleifera Lam. is a fast-growing and drought-resistant tree of the Moringaceae family. The tree is known with some common names: miracle, ben oil, drumstick, horseradish or simply moringa. The plant grows in a variety of environments including harsh conditions. The plant has a high content of phytonutrients, being used as natural integrators to cure malnutrition. Phytochemical studies of plant organs showed the plant as a rich source of primary and secondary metabolites belonging to different classes of organic compounds. Pharmacological studies confirmed the use of the plant to cure several diseases and to possess nutraceutical properties. This review is aimed to contribute to the knowledge of M. oleifera by providing its plant description, phytochemistry and pharmacology. Full article

(This article belongs to the Special Issue Botany, Phytochemistry and Pharmacology in Traditional Herbal Medicine)

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16 pages, 5886 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Identification and Bioinformatics Analysis of Auxin Response Factor Genes in Highbush Blueberry

by Yu Zong, Lili Gu, Zhuli Shen, Haiting Kang, Yongqiang Li, Fanglei Liao, Lishan Xu and Weidong Guo

Horticulturae 2021, 7(10), 403; https://doi.org/10.3390/horticulturae7100403 - 15 Oct 2021

Cited by 5 | Viewed by 1936

Abstract

Auxin response factors (ARFs) are a transcription factor family that regulates the expression of auxin phase-responsive genes. Here, we performed a genome-wide investigation of the tetraploid blueberry (Vaccinium corymbosum cv. ‘Draper’) genome sequence. Physical and chemical properties, phylogenetic evolution, gene structure, conservative [...] Read more.

Auxin response factors (ARFs) are a transcription factor family that regulates the expression of auxin phase-responsive genes. Here, we performed a genome-wide investigation of the tetraploid blueberry (Vaccinium corymbosum cv. ‘Draper’) genome sequence. Physical and chemical properties, phylogenetic evolution, gene structure, conservative motifs, chromosome location, and cis-acting elements of blueberry ARF genes were comprehensively evaluated. A total of 70 blueberry ARF genes (VcARF) were found in its genome, which could be divided into six subfamilies. VcARF genes were unevenly distributed on 40 chromosomes and were observed to encode protein sequences ranging in length from 162 to 1117 amino acids. Their exon numbers range from 2 to 22. VcARF promoter regions contain multiple functional domains associated with light signaling, aerobic metabolism, plant hormones, stress, and cell cycle regulation. More family members of VcARF genes were discovered in blueberry than in previously studied plants, likely because of the occurrence of whole-genome duplication and/or tandem duplication. VcARF expression patterns were analyzed at different stages of fruit development, and VcARF3, VcARF4, VcARF14, VcARF37, and VcARF52 were observed to play important roles. VcARF3 and VcARF4 appeared to function as repressors, while VcARF14 acted as an essential factor in fruit firmness differences between firm and soft flesh cultivars. Full article

(This article belongs to the Special Issue Genetics and Breeding of Fruit Trees)

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9 pages, 1921 KiB

Open AccessEditor’s ChoiceArticle

Variability of Polyphenolic Compounds and Biological Activities among Perilla frutescens var. crispa Genotypes

by Hyun Ju Ju, Kyeoung Cheol Kim, Heekyu Kim, Ju-Sung Kim and Tae Kyung Hyun

Horticulturae 2021, 7(10), 404; https://doi.org/10.3390/horticulturae7100404 - 15 Oct 2021

Cited by 10 | Viewed by 2173

Abstract

Perilla frutescens var. crispa (Pfc) of the family Lamiaceae is used as a medicinal plant due to its pharmacological properties. Although Pfc is an important resource for the medical nutrition industry, the variability in phytonutrients and biological activities among genotypes of Pfc is [...] Read more.

Perilla frutescens var. crispa (Pfc) of the family Lamiaceae is used as a medicinal plant due to its pharmacological properties. Although Pfc is an important resource for the medical nutrition industry, the variability in phytonutrients and biological activities among genotypes of Pfc is not well understood. The effects of genotype on the phytochemical composition, antioxidant activities, antimelanogenic principles, and anti-inflammatory effects of Pfc were determined using eight Pfc genotypes. Using HPLC analysis, we identified 30 polyphenolic compounds from Pfc, although variation was observed in the polyphenolic composition of Pfc genotypes. Pfc 5 exhibited antimelanogenic activity in B16F10 melanoma cells via inhibition of tyrosinase activity. In addition, Pfc 2 strongly inhibited lipopolysaccharide-induced nitric oxide production through translational downregulation of inducible NOS in RAW264 murine macrophages. Taken together, the results of our study reveal the significant impacts of genotype on phytonutrients and biological activities. This finding will assist in the breeding and genetic engineering of Pfc in order to meet future phytonutrition and health challenges. Full article

(This article belongs to the Special Issue Botany, Phytochemistry and Pharmacology in Traditional Herbal Medicine)

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14 pages, 3467 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Identification of the 1-Aminocyclopropane-1-carboxylic Acid Synthase (ACS) Genes and Their Possible Role in Sand Pear (Pyrus pyrifolia) Fruit Ripening

by Jing-Guo Zhang, Wei Du, Jing Fan, Xiao-Ping Yang, Qi-Liang Chen, Ying Liu, Hong-Ju Hu and Zheng-Rong Luo

Horticulturae 2021, 7(10), 401; https://doi.org/10.3390/horticulturae7100401 - 14 Oct 2021

Cited by 2 | Viewed by 1929

Abstract

Ethylene production is negatively associated with storage life in sand pear (Pyrus pyrifolia Nakai), particularly at the time of fruit harvest. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is the rate-limiting enzyme in ethylene biosynthesis and is considered to be important for fruit storage life. [...] Read more.

Ethylene production is negatively associated with storage life in sand pear (Pyrus pyrifolia Nakai), particularly at the time of fruit harvest. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is the rate-limiting enzyme in ethylene biosynthesis and is considered to be important for fruit storage life. However, the candidate ACS genes and their roles in sand pear remain unclear. The present study identified 13 ACS genes from the sand pear genome. Phylogenetic analysis categorized these ACS genes into four subgroups (type I, type II, type III and putative AAT), and indicated a close relationship between sand pear and Chinese white pear (P. bretschneideri). According to the RNA-seq data and qRT-PCR analysis, PpyACS1, PpyACS2, PpyACS3, PpyACS8, PpyACS9, PpyACS12 and PpyACS13 were differently expressed in climacteric and non-climacteric-type pear fruits, ‘Ninomiyahakuri’ and ‘Eli No.2’, respectively, during fruit ripening. In addition, the expressions of PpyACS2, PpyACS8, PpyACS12 and PpyACS13 were found to be associated with system 1 of ethylene production, while PpyACS1, PpyACS3, and PpyACS9 were found to be associated with system 2, indicating that these ACS genes have different roles in ethylene biosynthesis during fruit development. Overall, our study provides fundamental knowledge on the characteristics of the ACS gene family in sand pear, in addition to their possible roles in fruit ripening. Full article

(This article belongs to the Special Issue Genetics and Breeding of Fruit Trees)

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14 pages, 1762 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Mycorrhiza-and Trichoderma-Mediated Elicitation of Secondary Metabolism and Modulation of Phytohormone Profile in Tomato Plants

by Giusy Iula, Begoña Miras-Moreno, Luigi Lucini and Marco Trevisan

Horticulturae 2021, 7(10), 394; https://doi.org/10.3390/horticulturae7100394 - 12 Oct 2021

Cited by 6 | Viewed by 3359

Abstract

Arbuscular mycorrhiza and Trichoderma are well-known beneficial fungi whose plant growth promotion and defense elicitation effects are known. However, the molecular and biochemical processes underlying the beneficial effects of these priming microorganisms have not been fully elucidated yet. On this basis, the present [...] Read more.

Arbuscular mycorrhiza and Trichoderma are well-known beneficial fungi whose plant growth promotion and defense elicitation effects are known. However, the molecular and biochemical processes underlying the beneficial effects of these priming microorganisms have not been fully elucidated yet. On this basis, the present work aimed to use metabolomics to dissect comprehensively the modulation of secondary metabolism induced by mycorrhiza and Trichoderma, using tomato as a model plant. To this aim, either mycorrhiza or Trichoderma were applied to tomato roots at transplanting using a commercial formulation and then harvested once the mutualistic relationship was well established. Shoots were analyzed using an MS-based untargeted metabolomics approach, and differential metabolites identified by multivariate statistics were subjected to pathway analysis. Together with promoting plant growth, the treatments induced a broad molecular reprogramming with the phenylpropanoid biosynthetic pathway (including defense phenolics like coumarins and glycosylated anthocyanins) being strongly elicited. An accumulation of auxins, cytokinins, and jasmonate (especially after treatment with Trichoderma) could be observed concerning phytohormone profiles. Overall, the broad and distinctive effects triggered by mycorrhiza and Trichoderma in tomato secondary metabolism supported both plant growth promotion and immunity. Full article

(This article belongs to the Special Issue Biostimulants and Plant Elicitors to Mitigate the Effect of Biotic and Abiotic Stress)

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21 pages, 1437 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Plant Tolerance to Drought Stress in the Presence of Supporting Bacteria and Fungi: An Efficient Strategy in Horticulture

by Agnieszka Hanaka, Ewa Ozimek, Emilia Reszczyńska, Jolanta Jaroszuk-Ściseł and Maria Stolarz

Horticulturae 2021, 7(10), 390; https://doi.org/10.3390/horticulturae7100390 - 11 Oct 2021

Cited by 32 | Viewed by 6374

Abstract

Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed [...] Read more.

Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed different strategies to cope with stress by morphological, physiological, anatomical, and biochemical responses. First, visible changes influence plant biomass and consequently limit the yield of crops. The presented review was undertaken to discuss the impact of climate change with respect to drought stress and its impact on the performance of plants inoculated with plant growth-promoting microorganisms (PGPM). The main challenge for optimal performance of horticultural plants is the application of selected, beneficial microorganisms which actively support plants during drought stress. The most frequently described biochemical mechanisms for plant protection against drought by microorganisms are the production of phytohormones, antioxidants and xeroprotectants, and the induction of plant resistance. Rhizospheric or plant surface-colonizing (rhizoplane) and interior (endophytic) bacteria and fungi appear to be a suitable alternative for drought-stress management. Application of various biopreparations containing PGPM seems to provide hope for a relatively cheap, easy to apply and efficient way of alleviating drought stress in plants, with implications in productivity and food condition. Full article

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

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12 pages, 299 KiB

Open AccessEditor’s ChoiceArticle

Comparison between Fermentation and Ultrasound-Assisted Extraction: Which Is the Most Efficient Method to Obtain Antioxidant Polyphenols from Sambucus nigra and Punica granatum Fruits?

by Luana Beatriz dos Santos Nascimento, Antonella Gori, Ilaria Degano, Alessandro Mandoli, Francesco Ferrini and Cecilia Brunetti

Horticulturae 2021, 7(10), 386; https://doi.org/10.3390/horticulturae7100386 - 09 Oct 2021

Cited by 6 | Viewed by 2282

Abstract

Fruit extracts of Sambucus nigra L. (elderberry) and Punica granatum L. (pomegranate) have several applications in nutraceutical, cosmetics, and pharmaceutical industries thanks to their richness in antioxidant polyphenols, whose composition changes with the extraction method applied. We aimed to compare the efficiency of [...] Read more.

Fruit extracts of Sambucus nigra L. (elderberry) and Punica granatum L. (pomegranate) have several applications in nutraceutical, cosmetics, and pharmaceutical industries thanks to their richness in antioxidant polyphenols, whose composition changes with the extraction method applied. We aimed to compare the efficiency of the fermentation extraction, recently applied by industries, with the ultrasound-assisted extraction–UAE, a well-known and efficient technique, on the yield of antioxidant polyphenols from elderberry fruits and pomegranate fruit-peels. Extracts were obtained by both methods, analyzed by high-performance liquid chromatography (HPLC) and the antioxidant capacities were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Hydroxyl Radical Scavenging (HRS) assays. The main compounds detected in elderberry were caffeoyl and quercetin derivatives, present in higher amounts in UAE extracts. In pomegranate, punicalagin were the main constituents, also detected in higher contents in the UAE extracts compared to fermented ones. The UAE was more suitable for extracting anthocyanins from pomegranate. In addition, higher antioxidant capacities were observed in UAE extracts, possibly due to their richness in polyphenols. Therefore, despite the recent wide applicability and the good performance of the fermentation process, the UAE may be considered more efficient for the extraction of polyphenols from S. nigra and P. granatum fruits and may be used to obtain polyphenolic antioxidant extracts to be applied by several industries. Full article

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

23 pages, 3912 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of 130 Eggplant (Solanum melongena L.) Genotypes for Future Breeding Program Based on Qualitative and Quantitative Traits, and Various Genetic Parameters

by Md. Shalim Uddin, Masum Billah, Rozina Afroz, Sajia Rahman, Nasrin Jahan, Md. Golam Hossain, Shamim Ara Bagum, Md. Sorof Uddin, Abul Bashar Mohammad Khaldun, Md. Golam Azam, Neelima Hossain, Mohammad Abdul Latif Akanda, Majid Alhomrani, Ahmed Gaber and Akbar Hossain

Horticulturae 2021, 7(10), 376; https://doi.org/10.3390/horticulturae7100376 - 08 Oct 2021

Cited by 14 | Viewed by 3650

Abstract

Eggplant is an essential widespread year-round fruit vegetable. This study was conducted using 130 local germplasm of brinjal to select diverse parents based on the multiple traits selection index for the future breeding program. This selection was performed focusing on 14 qualitative and [...] Read more.

Eggplant is an essential widespread year-round fruit vegetable. This study was conducted using 130 local germplasm of brinjal to select diverse parents based on the multiple traits selection index for the future breeding program. This selection was performed focusing on 14 qualitative and 10 quantitative traits variation and genetic parameters namely, phenotypic and genotypic variance (PV and GV) and genotypic and phenotypic coefficients of variation (GCV and PCV), broad-sense heritability (hBS), genetic advance, traits association, genotype by trait biplot (G × T), heatmap analysis and multi-trait index based on factor analysis and genotype-ideotype distance (MGIDI). Descriptive statistics and analysis of variance revealed a wide range of variability for morpho-physiological traits. Estimated hBS for all the measured traits ranged from 10.6% to 93%, indicating that all the traits were highly inheritable. Genetic variances were low to high for most morpho-physiological traits, indicating complex genetic architecture. Yield per plant was significantly correlated with fruit diameter, fruits per plant, percent fruits infestation by brinjal shoot and fruit borer, and fruit weight traits indicating that direct selection based on fruit number and fruit weight might be sufficient for improvement of other traits. The first two principal components (PCs) explained about 81.27% of the total variation among lines for 38 brinjal morpho-physiological traits. Genotype by trait (G × T) biplot revealed superior genotypes with combinations of favorable traits. The average genetic distance was 3.53, ranging from 0.25 to 20.01, indicating high levels of variability among the germplasm. The heat map was also used to know the relationship matrix among all the brinjal genotypes. MGIDI is an appropriate method of selection based on multiple trait information. Based on the fourteen qualitative and ten quantitative traits and evaluation of various genetic parameters, the germplasm G80, G54, G66, and G120 might be considered as best parents for the future breeding program for eggplant improvement. Full article

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

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17 pages, 3548 KiB

Open AccessEditor’s ChoiceArticle

Effect of Foliar Supplied PGRs on Flower Growth and Antioxidant Activity of African Marigold (Tagetes erecta L.)

by Sadia Sadique, Muhammad Moaaz Ali, Muhammad Usman, Mahmood Ul Hasan, Ahmed F. Yousef, Muhammad Adnan, Shaista Gull and Silvana Nicola

Horticulturae 2021, 7(10), 378; https://doi.org/10.3390/horticulturae7100378 - 08 Oct 2021

Cited by 5 | Viewed by 2340

Abstract

Marigold is one of the commercially exploited flowering crops that belongs to the family Asteraceae. The production of economical yield and better quality of marigold flowers requires proper crop management techniques. Crop regulation is an important technique to make the marigold production profitable. [...] Read more.

Marigold is one of the commercially exploited flowering crops that belongs to the family Asteraceae. The production of economical yield and better quality of marigold flowers requires proper crop management techniques. Crop regulation is an important technique to make the marigold production profitable. This can be done by adopting application of plant growth regulators (PGRs). The present study was designed to investigate the effect of PGRs on flowering and antioxidant activity of two cultivars of African marigold (Tagetes erecta L.) viz. “Pusa Narangi Gainda” (hereinafter referred to as Narangi) and “Pusa Basanthi Gainda” (hereafter referred to as Basanthi). Plants were sprayed with abscisic acid (ABA), N-acetyl thiazolidine (NAD), gibberellic acid (GA₃), salicylic acid (SA), indole-3-butyric acid (IBA) and oxalic acid (OA) at the concentrations of 100, 150, 250, 300 and 800 mg·L⁻¹, each. Results revealed that the plants treated with 500–600 mg·L⁻¹ IBA exhibited maximum increase in floral diameter (34–51%). The use of 500–550 mg·L⁻¹ IBA exhibited maximal enhancement in flower fresh weight (21–92%). The exogenously applied OA significantly (p ≤ 0.05) improved flower dry weight, total phenolic contents, total flavonoid contents and reducing power ability of marigold plants. Overall, “Narangi” performed better than “Basanthi”, in terms of flowering and antioxidant activity. Conclusively, the results suggest that foliar application of PGRs favors flowering and antioxidant activity of African marigold. Full article

(This article belongs to the Special Issue Trends in Ornamental Plant Production)

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12 pages, 2742 KiB

Open AccessEditor’s ChoiceArticle

Dehydrins and Soluble Sugars Involved in Cold Acclimation of Rosa wichurana and Rose Cultivar ‘Yesterday’

by Lin Ouyang, Leen Leus, Ellen De Keyser and Marie-Christine Van Labeke

Horticulturae 2021, 7(10), 379; https://doi.org/10.3390/horticulturae7100379 - 08 Oct 2021

Cited by 4 | Viewed by 1445

Abstract

Rose is the most economically important ornamental plant. However, cold stress seriously affects the survival and regrowth of garden roses in northern regions. Cold acclimation was studied using two genotypes (Rosa wichurana and R. hybrida ‘Yesterday’) selected from a rose breeding program. [...] Read more.

Rose is the most economically important ornamental plant. However, cold stress seriously affects the survival and regrowth of garden roses in northern regions. Cold acclimation was studied using two genotypes (Rosa wichurana and R. hybrida ‘Yesterday’) selected from a rose breeding program. During the winter season (November to April), the cold hardiness of stems, soluble sugar content, and expression of dehydrins and the related key genes in the soluble sugar metabolism were analyzed. ‘Yesterday’ is more cold-hardy and acclimated faster, reaching its maximum cold hardiness in December. R. wichurana is relatively less cold-hardy, only reaching its maximum cold hardiness in January after prolonged exposure to freezing temperatures. Dehydrin transcripts accumulated significantly during November–January in both genotypes. Soluble sugars are highly involved in cold acclimation, with sucrose and oligosaccharides significantly correlated with cold hardiness. Sucrose occupied the highest proportion of total soluble sugars in both genotypes. During November–January, downregulation of RhSUS was found in both genotypes, while upregulation of RhSPS was observed in ‘Yesterday’ and upregulation of RhINV2 was found in R. wichurana. Oligosaccharides accumulated from November to February and decreased to a significantly low level in April. RhRS6 had a significant upregulation in December in R. wichurana. This study provides insight into the cold acclimation mechanism of roses by combining transcription patterns with metabolite quantification. Full article

(This article belongs to the Special Issue Breeding, Genetics and Genomics of Ornamental Plants)

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17 pages, 1903 KiB

Open AccessEditor’s ChoiceArticle

Light Quality Environment and Photomorphological Responses of Young Olive Trees

by Federico J. Ladux, Eduardo R. Trentacoste, Peter S. Searles and M. Cecilia Rousseaux

Horticulturae 2021, 7(10), 369; https://doi.org/10.3390/horticulturae7100369 - 06 Oct 2021

Cited by 6 | Viewed by 2613

Abstract

Tree densities have increased greatly in olive orchards over the last few decades. In many annual crop species, increased density reduces the horizontal red/far-red (R/FR) and blue/green (B/G) ratios during canopy development even before direct shading occurs, and such changes are known to [...] Read more.

Tree densities have increased greatly in olive orchards over the last few decades. In many annual crop species, increased density reduces the horizontal red/far-red (R/FR) and blue/green (B/G) ratios during canopy development even before direct shading occurs, and such changes are known to alter plant morphology. This study with olive trees evaluated: (1) whether the leaf area index (LAI) of neighboring trees modifies the light quality environment prior to a tree being directly shaded and (2) the potential morphological responses of three olive cultivars to changes in light quality. Increasing LAI using different spatial arrangements of potted, three-year-old trees reduced the horizontal R/FR ratio more than that of the B/G ratio. Cultivar-specific responses to low R/FR ratio were observed for individual leaf area and aboveground/belowground biomass ratio using laterally positioned FR mirrors or green fences. No statistically significant responses were detected in response to green vegetation fences that reduced both horizontal R/FR and B/G ratios, but a cluster analysis grouped together the overall morphological responses to both FR mirrors and green fences. These results in olive trees suggest that cultivar differences in response to light quality may be relevant for understanding adaptation to dense orchards and identifying cultivars best suited to them. Full article

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

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16 pages, 1023 KiB

Open AccessEditor’s ChoiceArticle

“Oh, You Shouldn’t Have!” Understanding Key Factors Impacting Cut Flowers Gifting Preferences in Germany

by Meike Rombach, David L. Dean, Nicole J. Olynk Widmar and Vera Bitsch

Horticulturae 2021, 7(10), 368; https://doi.org/10.3390/horticulturae7100368 - 06 Oct 2021

Cited by 4 | Viewed by 2342

Abstract

Cut flower gifting preferences are relatively unexplored in Germany. This study proposes a model that investigates the impact of attitudinal, experiential, and socio-demographic factors on the cut flower gifting preferences of German consumers. For this purpose, an online survey with a representative sample [...] Read more.

Cut flower gifting preferences are relatively unexplored in Germany. This study proposes a model that investigates the impact of attitudinal, experiential, and socio-demographic factors on the cut flower gifting preferences of German consumers. For this purpose, an online survey with a representative sample of 978 German residents was conducted. Partial least squares structural equation modelling shows that active and passive engagement with plants and nature positively impact cut flower giving preferences through cut flower knowledge, cut flower fondness, and perceived versatility of cut flowers. For German women and men, the largest driver of cut flower giving preferences is the versatility of cut flowers. For women, cut flower fondness is the second largest driver of cut flower gifting preferences, whereas for men subjective knowledge was the second largest driver. Other socio-demographic factors (age, income, education) were not found to impact cut flower giving preferences. Full article

(This article belongs to the Section Horticultural Economics, Policy, Business Management and Marketing)

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10 pages, 258 KiB

Open AccessEditor’s ChoiceArticle

The Dominance of Chitosan Hydrochloride over Modern Natural Agents or Basic Substances in Efficacy against Phytophthora infestans, and Its Safety for the Non-Target Model Species Eisenia fetida

by Martin Žabka and Roman Pavela

Horticulturae 2021, 7(10), 366; https://doi.org/10.3390/horticulturae7100366 - 05 Oct 2021

Cited by 6 | Viewed by 1664

Abstract

Growing pressure to reduce the environmental pesticide burden has the greatest impact on agriculture and crop protection. There is an enormous increase in the demand for research on new, effective, naturally based agents that do not pose an environmental risk. Phytophthora infestans is [...] Read more.

Growing pressure to reduce the environmental pesticide burden has the greatest impact on agriculture and crop protection. There is an enormous increase in the demand for research on new, effective, naturally based agents that do not pose an environmental risk. Phytophthora infestans is one of the most destructive phytopathogens, especially in cases where synthetic fungicides are not allowed. This paper describes the high efficacy and safety of the natural polymer chitosan under in vitro and in vivo conditions and its dominance over other natural agents or products. Chitosan demonstrated the highest efficacy against P. infestans. A concentration of 0.2–0.4% was highly effective. The protective effect of chitosan was 99.3% in natural conditions. Direct activity, equivalent to synthetic fungicides (MIC50 0.293 mg/mL), was confirmed. Chitosan was rated non-toxic to useful non-target species. We promote further chitosan expansion within legislation and implementation of chitosan as a safe substance that could reduce the pesticide burden, particularly in eco-friendly plant protection and production of non-harmful foods. Full article

(This article belongs to the Special Issue Biological Control of Pre- and Postharvest Fungal Diseases)

17 pages, 3001 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Morphological, Physiological, and Biochemical Responses of Zinnia to Drought Stress

by Stefania Toscano and Daniela Romano

Horticulturae 2021, 7(10), 362; https://doi.org/10.3390/horticulturae7100362 - 04 Oct 2021

Cited by 11 | Viewed by 3192

Abstract

Bedding plants in the nursery phase are often subject to drought stress because of the small volume of the containers and the hydraulic conductivity of organic substrates used. To analyse the morphological, physiological, and enzymatic responses of zinnia (Zinnia elegans L.) plants [...] Read more.

Bedding plants in the nursery phase are often subject to drought stress because of the small volume of the containers and the hydraulic conductivity of organic substrates used. To analyse the morphological, physiological, and enzymatic responses of zinnia (Zinnia elegans L.) plants at different irrigation levels, four treatments were performed: irrigated at 100% (100% field capacity, FC); light deficit irrigation (75% FC), medium deficit irrigation (50% FC), and severe deficit irrigation (25% FC). The growth of zinnia was significantly influenced by drought stress treatments. Different morphological parameters (dry biomass, leaf number, root to shoot ratio (R/S)) were modified only in the more severe drought stress treatment (25% FC). The stomata density increased in 50% FC and 25% FC, while the stomata size was reduced in 25% FC. The net photosynthesis, stomatal conductance, and transpiration were reduced in 50% FC and 25% FC. The relative water content (RWC) was reduced in 25% FC. Severe drought stress (25% FC) increased proline content up to seven-fold. Catalase (CAT), peroxidase (GPX), and superoxide dismutase (SOD) activity significantly increased in 50% FC and 25% FC. Principal component analysis (PCA) showed that the morphological and physiological parameters were mostly associated with the 100% FC and 75% FC treatments of the biplot, whereas the stomata density, R/S ratio, and antioxidant enzymes (GPX, CAT) were associated with 50% FC, and proline and DPPH were associated with 25% FC, respectively. Full article

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

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19 pages, 8049 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Continuous Monitoring of Olive Fruit Growth by Automatic Extensimeter in Response to Vapor Pressure Deficit from Pit Hardening to Harvest

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

Horticulturae 2021, 7(10), 349; https://doi.org/10.3390/horticulturae7100349 - 30 Sep 2021

Cited by 7 | Viewed by 2012

Abstract

Recently, several studies on olive fruit growth have focused on circadian monitoring as an important orchard management tool. The olive fruit growth trend is described by double sigmoid model with four growth phases, where the third phase spans from the end of pit [...] Read more.

Recently, several studies on olive fruit growth have focused on circadian monitoring as an important orchard management tool. The olive fruit growth trend is described by double sigmoid model with four growth phases, where the third phase spans from the end of pit hardening to initial fruit maturation, and the last phase includes olive maturation up to fruit drop. Environmental factors play an important role in fruit growth, with vapor pressure deficit (VPD) being a keystone factor. Our experiment was designed to hourly monitor olive (Olea europaea L. cv. ‘Frantoio’) fruit transversal diameter from approximately initial pit hardening (II Phase), extension (III Phase) until harvest time (IV Phase) in the attempt to determine whether fruit growth dynamically responds to environmental variables such as diurnal VPD change in different stages of fruit development. Automatic extensimeters were applied in open field and VPD was calculated from data of our weather station. Throughout the experiment period, the circadian model of fruit growth showed two steps: shrinkage and expansion. Almost in all days of the third phase of fruit growth, daily response of transversal diameter to VPD formed complete clockwise hysteresis loops. During the fourth phase of fruit growth, with increasing fruit maturation, the complete clockwise hysteresis loop experienced some abnormality. At the fourth stage of fruit growth there were incomplete and partial clockwise hysteresis loops. We conclude that hysteresis can be employed to detect the shift between the end of the third phase (cell expansion) and the beginning of the fourth phase (fruit maturation) of fruit growth. The disappearance of the complete clockwise hysteresis loop and the substitution with incomplete, or partial clockwise hysteresis loops was observable only in the fourth stage of fruit growth. These results can be valuable for any smart fruit management of olive fruit production. Full article

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17 pages, 1467 KiB

Open AccessEditor’s ChoiceArticle

Exogenous Application of Chitosan Alleviate Salinity Stress in Lettuce (Lactuca sativa L.)

by Geng Zhang, Yuanhua Wang, Kai Wu, Qing Zhang, Yingna Feng, Yu Miao and Zhiming Yan

Horticulturae 2021, 7(10), 342; https://doi.org/10.3390/horticulturae7100342 - 24 Sep 2021

Cited by 22 | Viewed by 3233

Abstract

Soil salinity is one of the major factors that affect plant growth and decrease agricultural productivity worldwide. Chitosan (CTS) has been shown to promote plant growth and increase the abiotic stress tolerance of plants. However, it still remains unknown whether the application of [...] Read more.

Soil salinity is one of the major factors that affect plant growth and decrease agricultural productivity worldwide. Chitosan (CTS) has been shown to promote plant growth and increase the abiotic stress tolerance of plants. However, it still remains unknown whether the application of exogenous CTS can mitigate the deleterious effects of salt stress on lettuce plants. Therefore, the current study investigated the effect of foliar application of exogenous CTS to lettuce plants grown under 100 mM NaCl saline conditions. The results showed that exogenous CTS increased the lettuce total leaf area, shoot fresh weight, and shoot and root dry weight, increased leaf chlorophyll a, proline, and soluble sugar contents, enhanced peroxidase and catalase activities, and alleviated membrane lipid peroxidation, in comparison with untreated plants, in response to salt stress. Furthermore, the application of exogenous CTS increased the accumulation of K⁺ in lettuce but showed no significant effect on the K⁺/Na⁺ ratio, as compared with that of plants treated with NaCl alone. These results suggested that exogenous CTS might mitigate the adverse effects of salt stress on plant growth and biomass by modulating the intracellular ion concentration, controlling osmotic adjustment, and increasing antioxidant enzymatic activity in lettuce leaves. Full article

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

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21 pages, 11256 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Cold Stress in Citrus: A Molecular, Physiological and Biochemical Perspective

by Amparo Primo-Capella, Mary-Rus Martínez-Cuenca and María Ángeles Forner-Giner

Horticulturae 2021, 7(10), 340; https://doi.org/10.3390/horticulturae7100340 - 24 Sep 2021

Cited by 13 | Viewed by 3660

Abstract

Due to climate change, we are forced to face new abiotic stress challenges like cold and heat waves that currently result from global warming. Losses due to frost and low temperatures force us to better understand the physiological, hormonal, and molecular mechanisms of [...] Read more.

Due to climate change, we are forced to face new abiotic stress challenges like cold and heat waves that currently result from global warming. Losses due to frost and low temperatures force us to better understand the physiological, hormonal, and molecular mechanisms of response to such stress to face losses, especially in tropical and subtropical crops like citrus fruit, which are well adapted to certain weather conditions. Many of the responses to cold stress that are found are also conserved in citrus. Hence, this review also intends to show the latest work on citrus. In addition to basic research, there is a great need to employ and cultivate new citrus rootstocks to better adapt to environmental conditions. Full article

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

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11 pages, 628 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Intercropping Vicia sativa L. Improves the Moisture, Microbial Community, Enzyme Activity and Nutrient in Rhizosphere Soils of Young Kiwifruit Plants and Enhances Plant Growth

by Qiuping Wang, Cheng Zhang, Jiaohong Li, Xiaomao Wu, Youhua Long and Yue Su

Horticulturae 2021, 7(10), 335; https://doi.org/10.3390/horticulturae7100335 - 23 Sep 2021

Cited by 13 | Viewed by 2211

Abstract

Drought, low nutrition, and weeds have become the major limiting factors of young kiwifruit orchards. In this study, the effects of intercropping Vicia sativa L. on the moisture, microbe community, enzyme activity, and nutrients in rhizosphere soils of young kiwifruit plants and their [...] Read more.

Drought, low nutrition, and weeds have become the major limiting factors of young kiwifruit orchards. In this study, the effects of intercropping Vicia sativa L. on the moisture, microbe community, enzyme activity, and nutrients in rhizosphere soils of young kiwifruit plants and their growth were investigated. The results show that intercropping V. sativa could effectively enhance soil moisture by 1.39–1.47 folds compared with clean tillage. Moreover, intercropping V. sativa could significantly (p < 0.01) increase the microbial community, enzyme activity and nutrient of kiwifruit rhizosphere soils, and improve plant height, stem girth, leaf number, maximum leaf length, maximum leaf width, and chlorophyll content of young kiwifruit plants by 43.60%, 18.68%, 43.75%, 18.09%, 21.15%, and 67.57% compared to clean tillage, respectively. The moisture, microbial quantity, enzyme activity, and nutrients in rhizosphere soils of young kiwifruit plants exhibited good correlations with their plant height, stem girth, leaf number, maximum leaf length, maximum leaf width, and chlorophyll content. This study highlights that intercropping V. sativa in young kiwifruit orchard can be used as an effective, labor-saving, economical and sustainable practice to improve the moisture, microbial community, enzyme activity, and nutrient of soils, and enhance kiwifruit plant growth and control weeds. Full article

(This article belongs to the Special Issue Breeding, Cultivation and Postharvest Managements of Kiwifruit)

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14 pages, 3421 KiB

Open AccessEditor’s ChoiceArticle

Root Architecture, Growth and Photon Yield of Cucumber Seedlings as Influenced by Daily Light Integral at Different Stages in the Closed Transplant Production System

by Yifei Wang, Yangyang Chu, Ze Wan, Geng Zhang, Lei Liu and Zhengnan Yan

Horticulturae 2021, 7(9), 328; https://doi.org/10.3390/horticulturae7090328 - 21 Sep 2021

Cited by 8 | Viewed by 3159

Abstract

Optimizing light conditions for vegetable seedling production in a closed transplant production system is critical for plant growth and seedling production. Additionally, energy use efficiency should be considered by growers when managing the light environment. In the present study, cucumber seedlings (Cucumis [...] Read more.

Optimizing light conditions for vegetable seedling production in a closed transplant production system is critical for plant growth and seedling production. Additionally, energy use efficiency should be considered by growers when managing the light environment. In the present study, cucumber seedlings (Cucumis sativus L. cv. Tianjiao No. 5) were grown under six different daily light integrals (DLIs) at 8.64, 11.52, 14.40, 17.28, 23.04, and 28.80 mol m⁻² d⁻¹ created by two levels of photosynthetic photon flux density (PPFD) of 200 and 400 μmol m⁻² s⁻¹ combined with photoperiod of 12, 16 and 20 h d⁻¹ provided by white light-emitting diodes (LEDs) in a closed transplant production system for 21 days. Results indicated that quadratic functions were observed between fresh and dry weights of cucumber seedlings and DLI at 6, 11, 16, and 21 days after sowing. Generally, higher DLI resulted in longer root length, bigger root volume and root surface area accompanied with shorter plant height and hypocotyl length; however, no significant differences were observed in root length, root volume, and root surface area as DLI increased from 14.40 to 28.80 mol m⁻² d⁻¹. Photon yield based on fresh and dry weights decreased with increasing DLI. In conclusion, increased DLI resulted in compact and vigorous morphology but reduced photon yield of cucumber seedlings produced in a closed transplant production system. In terms of plant growth and energy use efficiency, DLI at 14.40–23.04 mol m⁻² d⁻¹ was suggested for cucumber seedling production in the closed production system. Additionally, different control strategies should be applied at different growth stages of cucumber seedlings. Full article

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

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12 pages, 1049 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Unraveling the Interaction between Arbuscular Mycorrhizal Fungi and Camellia Plants

by Rui-Cheng Liu, Zhi-Yan Xiao, Abeer Hashem, Elsayed Fathi Abd_Allah, Yong-Jie Xu and Qiang-Sheng Wu

Horticulturae 2021, 7(9), 322; https://doi.org/10.3390/horticulturae7090322 - 17 Sep 2021

Cited by 9 | Viewed by 3807

Abstract

Camellia is a genus of evergreen shrubs or trees, such as C. japonica, C. sinensis, C. oleifera, etc. A group of beneficial soil microorganisms, arbuscular mycorrhizal fungi (AMF), inhabit the rhizosphere of these Camellia spp. A total of eight genera [...] Read more.

Camellia is a genus of evergreen shrubs or trees, such as C. japonica, C. sinensis, C. oleifera, etc. A group of beneficial soil microorganisms, arbuscular mycorrhizal fungi (AMF), inhabit the rhizosphere of these Camellia spp. A total of eight genera of Acaulospora, Entrophospora, Funneliformis, Gigaspora, Glomus, Pacispora, Scutellospora, and Sclerocystis were found to be associated with Camellia plants with Glomus and/or Acaulospora being most abundant. These mycorrhizal fungi can colonize the roots of Camellia spp. and thus form arbuscular mycorrhizal symbionts. AMF is an important partner of Camellia spp. in the field of physiological activities. Studies indicated that AMF inoculation has been shown to promote plant growth, improve nutrient acquisition and nutritional quality, and increase resistance to drought, salinity and heavy metal contamination in potted Camellia. This review thus provides a comprehensive overview of AMF species occurring in the rhizosphere of Camellia spp. and summarizes the variation in root AMF colonization rate as well as the environmental factors and soil nutrients affecting root colonization. The paper also reviews the effects of AMF on plant growth response, nutrient acquisition, food quality, and stress tolerance of Camellia spp. Full article

(This article belongs to the Special Issue Mycorrhizal Roles in Horticultural Plants)

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12 pages, 1399 KiB

Open AccessEditor’s ChoiceArticle

Leaf Morpho-Colorimetric Characterization of Different Grapevine Varieties through Changes on Plant Water Status

by Gastón Gutiérrez-Gamboa, Nicolás Torres-Huerta, Miguel Araya-Alman, Nicolás Verdugo-Vásquez, Yerko Moreno-Simunovic, Héctor Valdés-Gómez and César Acevedo-Opazo

Horticulturae 2021, 7(9), 315; https://doi.org/10.3390/horticulturae7090315 - 16 Sep 2021

Cited by 1 | Viewed by 2725

Abstract

(1) Background: Currently, some ampelographic methods are developing in order to identify grapevine varieties. For this purpose, morpho-colorimetric parameters in leaves have been analyzed by digital imagen analysis, but some environmental conditions may affect their determinations. (2) Methods: A research study was conducted [...] Read more.

(1) Background: Currently, some ampelographic methods are developing in order to identify grapevine varieties. For this purpose, morpho-colorimetric parameters in leaves have been analyzed by digital imagen analysis, but some environmental conditions may affect their determinations. (2) Methods: A research study was conducted to characterize leaf morpho-colorimetric parameters in five grapevine varieties growing under different plant water status and to discriminate them under these conditions. Leaves were collected in vines, and twelve leaf morpho-colorimetric and fractal dimension variables were assessed. (3) Results: Merlot presented the highest values of perimeter and area to perimeter ratio in leaves and higher leaf area than Chardonnay in both plant water conditions. Most of the leaf morpho-colorimetric variables allowed discriminating the grapevine varieties under the contrasted hydric conditions. Under non-water stress, Carmenère was not related to any measured parameters. Merlot was positively related to most of the leaf morphometric parameters, whereas Chardonnay presented the opposite behavior. RGB color system variables allowed discriminating the grapevine varieties under water stress conditions, and Sauvignon Blanc was not related to any measured parameter. Chardonnay and Pinot Noir were positively related to green color and negatively related to most of the leaf morphometric parameters, whereas Merlot showed the opposite behavior. (4) Conclusions: Leaf morpho-colorimetric and fractal dimension parameters were affected by plant water stress and more variables should be incorporated into the new ampelographic methods in order to characterize leaf morpho-colorimetric parameters of the different grapevine varieties more clearly. Full article

(This article belongs to the Section Viticulture)

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15 pages, 521 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Biostimulatory Action of Vegetal Protein Hydrolysate and the Configuration of Fruit Physicochemical Characteristics in Grafted Watermelon

by Georgios A. Soteriou, Youssef Rouphael, Maria G. Emmanouilidou, Chrystalla Antoniou, Angelos C. Kyratzis and Marios C. Kyriacou

Horticulturae 2021, 7(9), 313; https://doi.org/10.3390/horticulturae7090313 - 15 Sep 2021

Cited by 4 | Viewed by 1799

Abstract

Foliar application of a vegetal-derived protein hydrolysate as a biostimulant was assessed for possible interaction with the ripening of diploid watermelon grafted onto interspecific hybrid rootstock. Assessment encompassed crop performance; fruit morphometric and sensory quality traits; soluble carbohydrates; macrominerals; and bioactive composition at [...] Read more.

Foliar application of a vegetal-derived protein hydrolysate as a biostimulant was assessed for possible interaction with the ripening of diploid watermelon grafted onto interspecific hybrid rootstock. Assessment encompassed crop performance; fruit morphometric and sensory quality traits; soluble carbohydrates; macrominerals; and bioactive composition at 10, 20, 30, 40, and 50 days post anthesis (dpa). The biostimulant effect on yield components was confounded by the vigorous rootstock effect. Pulp firmness declined precipitously with cell enlargement from 10 to 30 dpa, and the biostimulant phyto-hormonal potential on firmness and rind thickness was masked by grafting. Pulp colorimetry was determined solely by ripening and peaked at 40 dpa. The biostimulant effect reduced lycopene content by 8% compared to the control. Total sugars coevolved with soluble solids content, peaked at 30 dpa, and then stabilized. Fructose and glucose prevailed during rapid fruit growth from 10 to 30 dpa and sucrose prevailed at advanced ripeness between 40–50 dpa, whereas acidity peaked at 20 dpa and then decreased. Potassium, which was the most abundant micromineral, peaked before full ripeness at 30 dpa. The biostimulant effect on the watermelon fruit ripening process is not granted, at least regarding the conditions this study was carried out under. The absence of biostimulant effect might relate to rootstock vigorousness, the grafted watermelon physiology, or the type of biostimulant used. Full article

(This article belongs to the Special Issue Grafting to Improve Yield and Quality of Vegetable Crops)

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12 pages, 2043 KiB

Open AccessEditor’s ChoiceArticle

Inactivation of Salmonella enterica and Colletotrichum gloeosporioides on Whole Mangoes by Application of an Antimicrobial Coating Containing Oregano Essential Oil

by Martha Sánchez-Tamayo, Claudia Ochoa-Martínez and Faith Critzer

Horticulturae 2021, 7(9), 305; https://doi.org/10.3390/horticulturae7090305 - 11 Sep 2021

Cited by 5 | Viewed by 3115

Abstract

Mangoes are susceptible to bacterial and fungal contamination during storage and transportation. This study investigated the effectiveness of pectin-based coatings containing oregano essential oil (OEO) to reduce Salmonella enterica contamination and decrease anthracnose disease on whole mangoes. A cocktail of five strains [...] Read more.

Mangoes are susceptible to bacterial and fungal contamination during storage and transportation. This study investigated the effectiveness of pectin-based coatings containing oregano essential oil (OEO) to reduce Salmonella enterica contamination and decrease anthracnose disease on whole mangoes. A cocktail of five strains of Salmonella spp. and Colletotrichum gloeosporioides strains was spot inoculated in mangoes to verify the antibacterial and antifungal activity of OEO. The inoculated mangoes were coated with pectin-based coatings containing 0, 0.5, 0.7, and 0.9% OEO. Coated fruits were stored for 11 days at 25 °C and 90% of relative humidity. All treatments with OEO effectively inhibited the growth of Salmonella, causing a reduction of 2.5 CFU/cm² compared to the control treatment (0% OEO). In addition, coatings effectively inhibited the growth of C. gloeosporioides on the mango surface after 9 days of storage to the same extent as the traditional Prochloraz fungicide. The efficacy of coatings treatments was between 88.06 and 96.68% compared to the control treatment. Sensory analysis showed that the OEO did not affect the quality attributes of coated mango. Results showed the potential benefits of applying the pectin-based coatings with OEO as an alternative to control S. enterica and C. gloeosporioides in whole mangoes. Full article

(This article belongs to the Special Issue Alternatives to Chemicals in Fruits and Vegetables Production and Storage)

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14 pages, 8877 KiB

Open AccessEditor’s ChoiceArticle

Nutrient Use in Vertical Farming: Optimal Electrical Conductivity of Nutrient Solution for Growth of Lettuce and Basil in Hydroponic Cultivation

by Hadis Hosseini, Vahid Mozafari, Hamid Reza Roosta, Hossein Shirani, Paulien C. H. van de Vlasakker and Mohsen Farhangi

Horticulturae 2021, 7(9), 283; https://doi.org/10.3390/horticulturae7090283 - 03 Sep 2021

Cited by 26 | Viewed by 7808

Abstract

During the past few decades, vertical farming has attracted a lot of interest as an alternative food production method. Vertical farms use engineered growth environments and hydroponic cultivation techniques for growing plants indoors. One of the important factors in vertical farming for the [...] Read more.

During the past few decades, vertical farming has attracted a lot of interest as an alternative food production method. Vertical farms use engineered growth environments and hydroponic cultivation techniques for growing plants indoors. One of the important factors in vertical farming for the cultivation of different plants is the amount of nutrients, which can be measured as electrical conductivity (EC). Studying the optimal EC is important for avoiding nutrient loss and deficiency in vertical farms. In this study, we investigated the effect of five EC levels (2, 1.2, 0.9, 0.7, and 0.5 dS m⁻¹) of Hoagland nutrient solution on the growth and development of basil cultivar ‘Emily’ and lettuce cultivar ‘Batavia-Caipira’. During the study, the environmental parameters were kept fixed using an automatic dosing machine. The experiment was done in automatic vertical farms using the hydroponic ebb–flow cultivation technique with a temperature of 20 ± 1 °C, relative humidity of 50–60%, CO₂ concentration of 450 ppm, pH = 6, the PPFD (photosynthetic photon flux density) of 215 ± 5.5 μmol m⁻² s⁻¹, and the photoperiod of 16:8 h (day/night). Each treatment was replicated four times. We studied the effects on several growth parameters (including the dry and fresh weight of leaves and roots, number of leaves, and leaf area) as well as the chlorophyll and nitrogen concentration of the leaves. According to the results, the basil and lettuce growth parameters among the five treatments have been significantly higher in the treatment with EC of 1.2 and 0.9 dS m⁻¹. These EC values are lower than the recommended EC value given as the optimum in the previous studies. However, the concentration of chlorophyll and nitrogen show different trends and were higher in full strength of nutrient solution with EC = 2 dS m⁻¹. Full article

(This article belongs to the Special Issue Nutrient Use Efficiency under Optimal and Stressful Conditions of Horticulture Plants)

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12 pages, 1184 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Improvement of Nutraceutical Value of Parsley Leaves (Petroselinum crispum) upon Field Applications of Beneficial Microorganisms

by Alessia Staropoli, Anastasia Vassetti, Maria Michela Salvatore, Anna Andolfi, Maria Isabella Prigigallo, Giovanni Bubici, Marina Scagliola, Pasquale Salerno and Francesco Vinale

Horticulturae 2021, 7(9), 281; https://doi.org/10.3390/horticulturae7090281 - 03 Sep 2021

Cited by 7 | Viewed by 3317

Abstract

Parsley (Petroselinum crispum) is an important aromatic herb that has gained importance in food and cosmetic industry, and it is used as medicinal plant due to the presence of compounds with biological activity. Several studies have demonstrated antioxidant, antimicrobial or cancer [...] Read more.

Parsley (Petroselinum crispum) is an important aromatic herb that has gained importance in food and cosmetic industry, and it is used as medicinal plant due to the presence of compounds with biological activity. Several studies have demonstrated antioxidant, antimicrobial or cancer chemopreventive activity of different parts of parsley plants. We showed that the nutritional value of parsley leaves can be improved by treatments with beneficial microorganisms on the field crop. Streptomyces fulvissimus strain AtB-42 and Trichoderma harzianum strain T22 were applied, as singly or in combination (microbial consortium), at transplanting and two weeks later. After harvesting, plants were subjected to metabolomic analysis by LC and GC-MS. Spectrometric analysis resulted in the identification of seven polar metabolites. Results showed a significant difference in relative abundance of these metabolites among treatments. The AtB-42 application, alone or in combination with T22, induced the accumulation of petroselinic acid, while T22, alone or in combination, induced the accumulation of xanthotoxol/bergaptol and its derivative xanthotoxin/bergapten. The microbial consortium increased the accumulation of capsanthone compared to single treatments. No statistically relevant differences were found for the volatile fraction. It can be concluded that S. fulvissimus and T. harzianum significantly induced metabolic profile change of parsley and the accumulation of metabolites with nutraceutical value. Full article

(This article belongs to the Collection Microbe-Assisted Production of Horticultural Crops)

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15 pages, 7206 KiB

Open AccessEditor’s ChoiceArticle

Development of Growth Estimation Algorithms for Hydroponic Bell Peppers Using Recurrent Neural Networks

by Joon-Woo Lee, Taewon Moon and Jung-Eek Son

Horticulturae 2021, 7(9), 284; https://doi.org/10.3390/horticulturae7090284 - 03 Sep 2021

Cited by 6 | Viewed by 2324

Abstract

As smart farms are applied to agricultural fields, the use of big data is becoming important. In order to efficiently manage smart farms, relationships between crop growth and environmental conditions are required to be analyzed. From this perspective, various artificial intelligence algorithms can [...] Read more.

As smart farms are applied to agricultural fields, the use of big data is becoming important. In order to efficiently manage smart farms, relationships between crop growth and environmental conditions are required to be analyzed. From this perspective, various artificial intelligence algorithms can be used as useful tools to quantify this relationship. The objective of this study was to develop and validate an algorithm that can interpret the crop growth rate response to environmental factors based on a recurrent neural network (RNN), and to evaluate the algorithm accuracy compared to the process-based model (PBM). The algorithms were trained with data from three growth periods. The developed methods were used to measure the crop growth rate. The algorithm consisted of eight environmental variables days after transplanting and two crop growth characteristics as input variables producing weekly crop growth rates as output. The RNN-based crop growth rate estimation algorithm was validated using data collected from a commercial greenhouse. The CropGro-bell pepper model was applied to compare and evaluate the accuracy of the developed algorithm. The training accuracies varied from 0.75 to 0.81 in all growth periods. From the validation result, it was confirmed that the accuracy was reliable in the commercial greenhouse. The accuracy of the developed algorithm was higher than that of the PBM. The developed algorithm can contribute to crop growth estimation with a limited number of data. Full article

(This article belongs to the Special Issue Trends of Horticultural Production and Practice in Intelligent Greenhouse)

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21 pages, 770 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Machine Vision for Ripeness Estimation in Viticulture Automation

by Eleni Vrochidou, Christos Bazinas, Michail Manios, George A. Papakostas, Theodore P. Pachidis and Vassilis G. Kaburlasos

Horticulturae 2021, 7(9), 282; https://doi.org/10.3390/horticulturae7090282 - 03 Sep 2021

Cited by 19 | Viewed by 3574

Abstract

Ripeness estimation of fruits and vegetables is a key factor for the optimization of field management and the harvesting of the desired product quality. Typical ripeness estimation involves multiple manual samplings before harvest followed by chemical analyses. Machine vision has paved the way [...] Read more.

Ripeness estimation of fruits and vegetables is a key factor for the optimization of field management and the harvesting of the desired product quality. Typical ripeness estimation involves multiple manual samplings before harvest followed by chemical analyses. Machine vision has paved the way for agricultural automation by introducing quicker, cost-effective, and non-destructive methods. This work comprehensively surveys the most recent applications of machine vision techniques for ripeness estimation. Due to the broad area of machine vision applications in agriculture, this review is limited only to the most recent techniques related to grapes. The aim of this work is to provide an overview of the state-of-the-art algorithms by covering a wide range of applications. The potential of current machine vision techniques for specific viticulture applications is also analyzed. Problems, limitations of each technique, and future trends are discussed. Moreover, the integration of machine vision algorithms in grape harvesting robots for real-time in-field maturity assessment is additionally examined. Full article

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

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13 pages, 800 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Advances and Challenges in RNA Interference Technology for Citrus Huanglongbing Vector Control

by Viviani Vieira Marques, Jéssika Angelotti-Mendonça and Sergio Ruffo Roberto

Horticulturae 2021, 7(9), 277; https://doi.org/10.3390/horticulturae7090277 - 02 Sep 2021

Cited by 7 | Viewed by 3075

Abstract

Citrus species, including sweet oranges, grapefruits, pomelos, and lemons, are the most widely cultivated trees and consumed fruits worldwide. In citrus orchard management, the control of Huanglongbing (HLB) disease and its insect vector Diaphorina citri (Asian citrus psyllid, ACP) represents a major global [...] Read more.

Citrus species, including sweet oranges, grapefruits, pomelos, and lemons, are the most widely cultivated trees and consumed fruits worldwide. In citrus orchard management, the control of Huanglongbing (HLB) disease and its insect vector Diaphorina citri (Asian citrus psyllid, ACP) represents a major global challenge. Consumers have been increasingly pushing the citrus production chain toward a more sustainable system, including stringent measures to prevent the use of chemical pesticides. In recent years, biotechnological advances have offered safe and environmentally friendly alternatives for crop production. Technologies such as RNA interference (RNAi)-mediated gene silencing have emerged as innovative tools for agricultural pest management. Here, we provide an overview of RNAi as a promising approach for ACP control and discuss the associated challenges. Despite the availability of specific silencing sequences aimed at a target gene of the insect pest, the uptake of double-stranded RNA is limited in hemipteran insects. In this context, improved delivery methods, stability maintenance, and RNAi response are considered the factors contributing to the increased effectiveness of exogenous RNAi against hemipteran pests. These approaches can serve as potential tools for efficient ACP control. Full article

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

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12 pages, 2530 KiB

Open AccessEditor’s ChoiceArticle

Fatty Acid Profile, Tocopherol Content of Seed Oil, and Nutritional Analysis of Seed Cake of Wood Apple (Limonia acidissima L.), an Underutilized Fruit-Yielding Tree Species

by Shrinivas Lamani, Konerira Aiyappa Anu-Appaiah, Hosakatte Niranjana Murthy, Yaser Hassan Dewir and Hail Z. Rihan

Horticulturae 2021, 7(9), 275; https://doi.org/10.3390/horticulturae7090275 - 01 Sep 2021

Cited by 11 | Viewed by 3030

Abstract

The present study was aimed at analyzing the fatty acid composition, tocopherols, and physico-chemical characterization of wood apple (Limonia acidissima L.) seed oil and the nutritional profile of seed cake. The fatty acids in seed oil were analyzed by gas chromatography–mass spectrometry [...] Read more.

The present study was aimed at analyzing the fatty acid composition, tocopherols, and physico-chemical characterization of wood apple (Limonia acidissima L.) seed oil and the nutritional profile of seed cake. The fatty acids in seed oil were analyzed by gas chromatography–mass spectrometry (GC-MS), and the total seed oil was 32.02 ± 0.08%, comprising oleic (21.56 ± 0.57%), alpha-linolenic (16.28 ± 0.29%), and linoleic acid (10.02 ± 0.43%), whereas saturated fatty acid content was 33.38 ± 0.60% including palmitic (17.68 ± 0.65%) and stearic acid (14.15 ± 0.27%). A greater amount of unsaturated fatty acids (52.37%) were noticed compared to saturated fatty acids (33.38%); hence the seed is highly suitable for nutritional and industrial applications. Gamma-tocopherol was present in a higher quantity (39.27 ± 0.07 mg/100 g) as compared to alpha (12.64 ± 0.01 mg/100 g) and delta (3.77 ± 0.00 mg/100 g) tocopherols, which are considered as natural antioxidants. The spectrophotometric technique was used for quantitative analysis of total phenolic content, and it revealed 135.42 ± 1.47 mg gallic acid equivalent /100 g DW in seed cake. All the results of the studied seed oil and cake showed a good source of natural functional ingredients for several health benefits. Full article

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

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