Horticulturae

18 pages, 927 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 7 | Viewed by 3125

Abstract

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

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

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

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18 pages, 3045 KiB

Open AccessFeature PaperReview

Fruit Colour and Novel Mechanisms of Genetic Regulation of Pigment Production in Tomato Fruits

by Silvia Gonzali and Pierdomenico Perata

Horticulturae 2021, 7(8), 259; https://doi.org/10.3390/horticulturae7080259 - 21 Aug 2021

Cited by 26 | Viewed by 7769

Abstract

Fruit colour represents a genetic trait with ecological and nutritional value. Plants mainly use colour to attract animals and favour seed dispersion. Thus, in many species, fruit colour coevolved with frugivories and their preferences. Environmental factors, however, represented other adaptive forces and further [...] Read more.

Fruit colour represents a genetic trait with ecological and nutritional value. Plants mainly use colour to attract animals and favour seed dispersion. Thus, in many species, fruit colour coevolved with frugivories and their preferences. Environmental factors, however, represented other adaptive forces and further diversification was driven by domestication. All these factors cooperated in the evolution of tomato fruit, one of the most important in human nutrition. Tomato phylogenetic history showed two main steps in colour evolution: the change from green-chlorophyll to red-carotenoid pericarp, and the loss of the anthocyanic pigmentation. These events likely occurred with the onset of domestication. Then spontaneous mutations repeatedly occurred in carotenoid and phenylpropanoid pathways, leading to colour variants which often were propagated. Introgression breeding further enriched the panel of pigmentation patterns. In recent decades, the genetic determinants underneath tomato colours were identified. Novel evidence indicates that key regulatory and biosynthetic genes undergo mechanisms of gene expression regulation that are much more complex than what was imagined before: post-transcriptional mechanisms, with RNA splicing among the most common, indeed play crucial roles to fine-tune the expression of this trait in fruits and offer new substrate for the rise of genetic variables, thus providing further evolutionary flexibility to the character. Full article

(This article belongs to the Special Issue Genetic Modification of Flower and Fruit Color Variations in Horticultural Crops)

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16 pages, 3420 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

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

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

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

Cited by 21 | Viewed by 3057

Abstract

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

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

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

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20 pages, 285 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

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

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

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

Cited by 14 | Viewed by 4676

Abstract

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

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

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

14 pages, 4861 KiB

Open AccessArticle

Productivity Enhancement of Cucumber (Cucumis sativus L.) through Optimized Use of Poultry Manure and Mineral Fertilizers under Greenhouse Cultivation

by Basheer Noman Sallam, Tao Lu, Hongjun Yu, Qiang Li, Zareen Sarfraz, Muhammad Shahid Iqbal, Shumaila Khan, Heng Wang, Peng Liu and Weijie Jiang

Horticulturae 2021, 7(8), 256; https://doi.org/10.3390/horticulturae7080256 - 20 Aug 2021

Cited by 15 | Viewed by 11411

Abstract

Cucumber, a widely cultivated vegetable, is mostly grown under greenhouse conditions. In recent years, the overuse of inorganic fertilizers for higher yield attainment adversely has affected human health and the environment. Therefore, a greenhouse experiment was designed to evaluate the effects of different [...] Read more.

Cucumber, a widely cultivated vegetable, is mostly grown under greenhouse conditions. In recent years, the overuse of inorganic fertilizers for higher yield attainment adversely has affected human health and the environment. Therefore, a greenhouse experiment was designed to evaluate the effects of different nutrient sources (poultry manure (PM) and mineral fertilizer (MF)) on productivity-enhancing parameters of cucumber via univariate and multivariate analyses. Amounts of PM and MF (NPK15:15:15) were added to coco-peat per cubic meter by weight/volume (w/v) ratios as follows: T₁ (control), 60 kg PM; T₂, 30 kg PM + 3 kg MF; T₃, 30 kg PM + 5 kg MF, and T₄, 30 kg PM + 7 kg MF. The univariate analysis performed on the collected data illustrated the significant enhancement in growth and productivity for the integrated use of PM and MF. Multivariate analyses (correlation, clustering, and Principal Component Analysis) validated the results of univariate analysis by differentiating treatments into two groups. The three treatments obtained a distinguished group from T₁ (Control) and did not show significant differences among each other, with a maximum yield increase by T₂ (74.6%). According to these results, T₂ could improve cucumber productivity under greenhouse conditions. It can be taken as recommendations for better quality and yield enhancement in future improvement programs and cucumber-related farming communities. 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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17 pages, 1695 KiB

Open AccessFeature PaperArticle

Reliability of a Handheld Bluetooth Colourimeter and Its Application to Measuring the Effects of Time from Harvest, Row Orientation and Training System on Nectarine Skin Colour

by Alessio Scalisi, Mark G. O’Connell, Daniele Pelliccia, Tim Plozza, Christine Frisina, Subhash Chandra and Ian Goodwin

Horticulturae 2021, 7(8), 255; https://doi.org/10.3390/horticulturae7080255 - 19 Aug 2021

Cited by 6 | Viewed by 2800

Abstract

This work aimed to (i) determine the reliability of a portable Bluetooth colourimeter for fruit colour measurements; (ii) characterise the changes in quantitative skin colour attributes in a nectarine cultivar in response to time from harvest; and (iii) determine the influence of row [...] Read more.

This work aimed to (i) determine the reliability of a portable Bluetooth colourimeter for fruit colour measurements; (ii) characterise the changes in quantitative skin colour attributes in a nectarine cultivar in response to time from harvest; and (iii) determine the influence of row orientation and training system on nectarine skin colour. The skin colour attributes measured with the colourimeter, namely L*, a* and b*, were calibrated and validated against a reference spectrophotometer. C* and h° were obtained from a* and b*. Skin colour was measured in situ from 42 days before to 6 days after harvest on ‘Majestic Pearl’ nectarines subjected to different row orientations and training systems. Validation models showed high reliability of colour estimations. The trends of colour attributes over time were characterised by cubic regression models, with h° proving to be the best parameter to describe changes of colour over time, with a clear link to the maturation process. No significant effects of row orientation and training system on skin colour were observed at harvest. Overall, the device proved reliable for fruit colour detection. Results of this study highlight the potential of h° as a quantitative index to monitor ripening prior to harvest in ‘Majestic Pearl’ nectarines. Full article

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

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13 pages, 4484 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 3 | Viewed by 2508

Abstract

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

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

(This article belongs to the Section Viticulture)

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12 pages, 1590 KiB

Open AccessArticle

Effect of Preharvest Application of CPPU and Perforated Packaging on the Postharvest Quality of Red-Fleshed Pitaya (Hylocereus polyrhizus sp.) Fruit

by Pai-Tsang Chang

Horticulturae 2021, 7(8), 253; https://doi.org/10.3390/horticulturae7080253 - 18 Aug 2021

Cited by 3 | Viewed by 3418

Abstract

The objective of this study was to investigate the effect of the preharvest application of forchlorfenuron (CPPU) and perforated polyethylene bag packaging (PPE) on maintaining the postharvest quality of red-fleshed cv. ‘Da-Hong’ pitaya (Hylocereus polyrhizus sp.) fruit. On the flowering day, 100 [...] Read more.

The objective of this study was to investigate the effect of the preharvest application of forchlorfenuron (CPPU) and perforated polyethylene bag packaging (PPE) on maintaining the postharvest quality of red-fleshed cv. ‘Da-Hong’ pitaya (Hylocereus polyrhizus sp.) fruit. On the flowering day, 100 mg·L⁻¹ CPPU was sprayed on the bracts and water was used as the control. After harvest, all fruits were divided into three package treatments, which were packed without bags, packed with and without PPE bags, and stored at 5 ± 0.5 °C and 90 ± 5% relative humidity for 21 days, followed by 7 days at 20 °C and 75 ± 5% relative humidity without bags for quality evaluation. Significantly higher bract thickness (2.26 vs. 1.44 mm), longer fruit length (120.5 vs. 109.04 mm), and greater firmness (1.56 vs. 1.04 kg·cm⁻²) were recorded for the CPPU treated fruit at harvest. Preharvest application of CPPU with perforated packaging resulted in significantly greener bracts, a lower yellow index, fewer chilling incidences, and a lower decay ratio, but there was a slight decrease in respiration rate during cold storage at 5 °C for 21 days. However, all criteria reached the threshold when fruits were transferred to 20 °C for 7 days. In conclusion, preharvest CPPU application plus perforated packaging is the best combination for the long-term storage of red-fleshed pitaya fruit at 5 °C. Full article

(This article belongs to the Special Issue Advances in Improving Fresh Produce Quality and Postharvest Shelf Life)

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18 pages, 2177 KiB

Open AccessReview

An Overview of the Practices and Management Methods for Enhancing Seed Production in Conifer Plantations for Commercial Use

by Yan Li, Xiang Li, Ming-Hui Zhao, Zhong-Yi Pang, Jia-Tong Wei, Mulualem Tigabu, Vincent L. Chiang, Heike Sederoff, Ronald Sederoff and Xi-Yang Zhao

Horticulturae 2021, 7(8), 252; https://doi.org/10.3390/horticulturae7080252 - 18 Aug 2021

Cited by 11 | Viewed by 4531

Abstract

Flowering, the beginning of the reproductive growth, is a significant stage in the growth and development of plants. Conifers are economically and ecologically important, characterized by straight trunks and a good wood quality and, thus, conifer plantations are widely distributed around the world. [...] Read more.

Flowering, the beginning of the reproductive growth, is a significant stage in the growth and development of plants. Conifers are economically and ecologically important, characterized by straight trunks and a good wood quality and, thus, conifer plantations are widely distributed around the world. In addition, conifer species have a good tolerance to biotic and abiotic stress, and a stronger survival ability. Seeds of some conifer species, such as Pinus koraiensis, are rich in vitamins, amino acids, mineral elements and other nutrients, which are used for food and medicine. Although conifers are the largest (giant sequoia) and oldest living plants (bristlecone pine), their growth cycle is relatively long, and the seed yield is unstable. In the present work, we reviewed selected literature and provide a comprehensive overview on the most influential factors and on the methods and techniques that can be adopted in order to improve flowering and seed production in conifers species. The review revealed that flowering and seed yields in conifers are affected by a variety of factors, such as pollen, temperature, light, water availability, nutrients, etc., and a number of management techniques, including topping off, pruning, fertilization, hormone treatment, supplementary pollination, etc. has been developed for improving cone yields. Furthermore, several flowering-related genes (FT, Flowering locus T and MADS-box, MCMI, AGAMOUS, DEFICIENCES and SRF) that play a crucial role in flowering in coniferous trees were identified. The results of this study can be useful for forest managers and for enhancing seed yields in conifer plantations for commercial use. Full article

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

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13 pages, 1026 KiB

Open AccessFeature PaperArticle

For a Better Understanding of the Effect of N Form on Growth and Chemical Composition of C₃ Vascular Plants under Elevated CO₂—A Case Study with the Leafy Vegetable Eruca sativa

by Lilian Schmidt and Jana Zinkernagel

Horticulturae 2021, 7(8), 251; https://doi.org/10.3390/horticulturae7080251 - 17 Aug 2021

Cited by 4 | Viewed by 3648

Abstract

Plant responses to elevated atmospheric CO₂ (eCO₂) are well studied, but the interactions of the carbon and nitrogen metabolism in the process are still not fully revealed. This is especially true for the role of nitrogen forms and their assimilation [...] Read more.

Plant responses to elevated atmospheric CO₂ (eCO₂) are well studied, but the interactions of the carbon and nitrogen metabolism in the process are still not fully revealed. This is especially true for the role of nitrogen forms and their assimilation by plants under eCO₂. This study investigated the interacting metabolic processes of atmospheric CO₂ levels and N form in the short-term crop arugula. The effects on physiological processes and their consequences for crop growth, yield and nutritional value were elucidated. Two varieties of arugula were grown in climate cabinets under 400 or 800 ppm CO₂, respectively. The plants were fertilized with either pure nitrate or ammonium-dominated-N. Photosynthetic CO₂ assimilation increased in response to eCO₂ regardless of the N form. This did not affect the assimilation of nitrate and consequently had no impact on the biomass of the plants. The extra photosynthates were not invested into the antioxidative compounds but were probably diverted towards the leaf structural compounds, thereby increasing dry mass and “diluting” several mineral elements. The fertilization of arugula with ammonium-dominated N had little benefits in terms of crop yield and nutritional quality. It is therefore not recommended to use ammonium-dominated N for arugula production under future elevated CO₂ levels. Full article

(This article belongs to the Special Issue Managing the Product Quality of Vegetable Crops under Abiotic Stress)

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11 pages, 1756 KiB

Open AccessArticle

Growth Response of Ginger (Zingiber officinale), Its Physiological Properties and Soil Enzyme Activities after Biochar Application under Greenhouse Conditions

by Dilfuza Jabborova, Stephan Wirth, Mosab Halwani, Mohamed F. M. Ibrahim, Islam H. El Azab, Mohamed M. El-Mogy and Amr Elkelish

Horticulturae 2021, 7(8), 250; https://doi.org/10.3390/horticulturae7080250 - 17 Aug 2021

Cited by 27 | Viewed by 6387

Abstract

This study aimed to investigate the effects of biochar (1%, 2%, and 3%) on seed germination, plant growth, root morphological characteristics, and physiological properties of ginger (Zingiber officinale) and soil enzymatic activities. Pot experiments under greenhouse conditions at 24 °C (day) [...] Read more.

This study aimed to investigate the effects of biochar (1%, 2%, and 3%) on seed germination, plant growth, root morphological characteristics, and physiological properties of ginger (Zingiber officinale) and soil enzymatic activities. Pot experiments under greenhouse conditions at 24 °C (day) and 16 °C (night) showed after six weeks that biochar additions of 2% and 3% significantly increased seed germination, plant height, leaf length, leaf number, as well as shoot and root dry weights compared to the control. Total root length significantly increased by 30%, 47%, and 74%, with increasing biochar contents (1%, 2%, and 3%) compared to the control. Root surface area, projected area, root diameter, and root volume reached a maximum at the 3% biochar treatment. The treatment with 2% biochar significantly increased fluorescein diacetate hydrolase and phenoloxidase activities by 33% and 59% compared to the control; so did the addition of 3% biochar, which significantly increased fluorescein diacetate hydrolases, phenoloxidase, and acid and alkaline phosphomonoesterase activity in soil compared to the control. Treatment with 3% biochar increased relative water content by 8%, chlorophyll content by 35%, and carotenoid content by 43% compared to the control. These results suggest that biochar can improve the performance of the rhizome of ginger and increase the activity of soil enzymes, thereby improving soil nutrient supply. Full article

(This article belongs to the Special Issue Soil, Water and Nitrates Management in Horticultural Production)

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16 pages, 5342 KiB

Open AccessCommunication

Use of Thermal Imaging to Assess Water Status in Citrus Plants in Greenhouses

by Gustavo Haddad Souza Vieira and Rhuanito Soranz Ferrarezi

Horticulturae 2021, 7(8), 249; https://doi.org/10.3390/horticulturae7080249 - 16 Aug 2021

Cited by 15 | Viewed by 6186

Abstract

The direct examination of plant canopy temperature can assist in optimizing citrus irrigation management in greenhouses. This study aimed to develop a method to measure canopy temperature using thermal imaging in one-year-old citrus plants in a greenhouse to identify plants with water stress [...] Read more.

The direct examination of plant canopy temperature can assist in optimizing citrus irrigation management in greenhouses. This study aimed to develop a method to measure canopy temperature using thermal imaging in one-year-old citrus plants in a greenhouse to identify plants with water stress and verify its potential to be used as a tool to assess citrus water status. The experiment was conducted for 48 days (27 November 2019 to 13 January 2020). We evaluated the influence of five levels of irrigation on two citrus species (‘Red Ruby’ grapefruit (Citrus paradisi) and ‘Valencia’ sweet orange (Citrus sinensis (L.) Osbeck)). Images were taken using a portable thermal camera and analyzed using open-source software. We determined canopy temperature, leaf photosynthesis and transpiration, and plant biomass. The results indicated a positive relationship between the amount of water applied and the temperature response of plants exposed to different water levels. Grapefruit and sweet orange plants that received less water and were submitted to water restrictions showed higher canopy temperatures than the air (up to 6 °C). The thermal images easily identified water-stressed plants. Our proof-of-concept study allowed quickly obtaining the canopy temperature using readily available equipment and can be used as a tool to assess citrus water status in one-year-old citrus plants in greenhouses and perhaps in commercial operations with mature trees in the field after specific experimentation. This technique, coupled with an automated system, can be used for irrigation scheduling. Thus, setting up a limit temperature is necessary to start the irrigation system and set the irrigation time based on the soil water content. To use this process on a large scale, it is necessary to apply an automation routine to process the thermal images in real time and remove the weeds from the background to determine the canopy temperature. Full article

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

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11 pages, 2805 KiB

Open AccessArticle

Morphological Characterization of Tetraploids of Limonium sinuatum (L.) Mill. Produced by Oryzalin Treatment of Seeds

by Shiro Mori, Masaki Yahata, Ayano Kuwahara, Yurina Shirono, Yasufumi Ueno, Misaki Hatanaka, Yoshimi Honda, Keita Sugiyama, Naho Murata, Yoshihiro Okamoto and Takahiro Wagatsuma

Horticulturae 2021, 7(8), 248; https://doi.org/10.3390/horticulturae7080248 - 15 Aug 2021

Cited by 8 | Viewed by 3191

Abstract

Limonium sinuatum (L.) Mill. (2n = 2x = 16) is a popular ornamental plant with dimorphism of pollen grains (type A and type B) and stigmas (papilla and cob-like). We applied polyploidy breeding to this species in order to introduce desirable traits. [...] Read more.

Limonium sinuatum (L.) Mill. (2n = 2x = 16) is a popular ornamental plant with dimorphism of pollen grains (type A and type B) and stigmas (papilla and cob-like). We applied polyploidy breeding to this species in order to introduce desirable traits. Tetraploid and mixoploid L. sinuatum plants were successfully obtained with oryzalin treatment of L. sinuatum ‘Early Blue’ seeds. All three tetraploids had increased leaf width, stomatal size, flower length, and pollen width compared to those of the diploid, and tetraploids had four germinal pores of pollen grains, whereas the diploid had three. All tetraploids had type A pollen grains and cob-like stigmas. Furthermore, the growth of cultivated tetraploid plants was slow, with later bolting and flowering times. Mixoploids Mixo-1 and Mixo-3 were estimated to be polyploidy periclinal chimeric plants consisting of a tetraploid L1 layer and diploid L2 layer, and Mixo-2 was estimated to be a polyploidy periclinal chimeric plant consisting of the diploid L1 layer and tetraploid L2 layer. Mixo-4 had tetraploid L1 and L2 layers. Mixoploids, except Mixo-4, had type A pollen grains and cob-like stigmas, whereas Mixo-4 had type B pollen grains and papilla stigmas. These polyploids will be useful as polyploidy breeding materials. Full article

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

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11 pages, 1788 KiB

Open AccessFeature PaperArticle

Selection on BrFLC1 Is Related to Intraspecific Diversity of Brassica rapa Vegetables

by Jiahe Liu, Xu Cai, Yufang Li, Yue Chen, Baozhen Gao, Runmao Lin, Jianli Liang, Xiaowu Wang and Jian Wu

Horticulturae 2021, 7(8), 247; https://doi.org/10.3390/horticulturae7080247 - 14 Aug 2021

Cited by 4 | Viewed by 3044

Abstract

Flowering time is important for Brassica rapa vegetables because premature bolting before harvest can lower yield and quality. FLOWERING LOCUS C (FLC) acts as a key repressor of flowering. In this study, we identified a nonsynonymous mutation at the 58th nucleotide [...] Read more.

Flowering time is important for Brassica rapa vegetables because premature bolting before harvest can lower yield and quality. FLOWERING LOCUS C (FLC) acts as a key repressor of flowering. In this study, we identified a nonsynonymous mutation at the 58th nucleotide of exon1 in BrFLC1 (named as Pe1+58 (A/C)) by screening resequencing data of 199 B. rapa accessions and verified this mutation as being related to flowering time variation. Strong linkage inheritance was detected between this locus and a previously reported splicing site mutation at intron 6 of BrFLC1 (Pi6+1 (G/A)), showing as co-occurrence of BrFLC1Pe1+58(A) and BrFLC1Pi6+1(G), named as haplotype H1: AG, or co-occurrence of BrFLC1Pe1+58(C) and BrFLC1Pi6+1(A), named as haplotype H2: CA. The frequency distribution of BrFLC1 haplotypes skewed to the haplotype H1 in turnip, broccoletto, mizuna, komatsuna, and taicai, while it was skewed to the haplotype H2 in caixin, pak choi, zicaitai, and wutacai. The frequencies of the two haplotypes were comparable in Chinese cabbage. This indicated that BrFLC1 haplotypes were related to B. rapa intraspecific diversification. Further analysis of a Chinese cabbage collection revealed that accessions from the spring ecotype preferred to keep H1: AG and almost all accessions from the summer ecotype were H2: CA. The early flowering haplotype of BrFLC1 was purified in summer Chinese cabbage, indicating that BrFLC1 had been strongly selected during genetic improvement of summer Chinese cabbages. A significant difference in flowering time of F₂ individuals with the homologous BrFLC1Pi6+1(G) allele but different BrFLC1Pe1+58 (A/C) alleles, indicated that this locus had independent genetic effects on flowering time. The newly identified allelic diversity of BrFLC1 can be used for breeding of resistance to premature bolting in B. rapa vegetables. Full article

(This article belongs to the Special Issue Advances in Brassica Crops Genomics and Breeding)

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13 pages, 1828 KiB

Open AccessArticle

Identification of Major Loci and Candidate Genes for Anthocyanin Biosynthesis in Broccoli Using QTL-Seq

by Chunqing Liu, Xueqin Yao, Guangqing Li, Lei Huang, Xinyan Wu and Zhujie Xie

Horticulturae 2021, 7(8), 246; https://doi.org/10.3390/horticulturae7080246 - 13 Aug 2021

Cited by 9 | Viewed by 3634

Abstract

Anthcyanins determine the colors of flowers, fruits, and purple vegetables and act as important health-promoting antioxidants. BT 126 represents a broccoli variety with a high content of anthocyanins (5.72 mg/g FW). Through QTL-seq bulk segregant analysis, the present study aimed to determine the [...] Read more.

Anthcyanins determine the colors of flowers, fruits, and purple vegetables and act as important health-promoting antioxidants. BT 126 represents a broccoli variety with a high content of anthocyanins (5.72 mg/g FW). Through QTL-seq bulk segregant analysis, the present study aimed to determine the quantitative trait loci (QTLs) involved in anthocyanin biosynthesis in the F2 population (n = 302), which was obtained by crossing BT 126 with a non-anthocyanin-containing SN 60. The whole-genome resequencing of purple (n = 30) and green (n = 30) bulk segregates detected ~1,117,709 single nucleotide polymorphisms (SNPs) in the B. oleracea genome. Two QTLs, tightly correlated with anthocyanin biosynthesis (p < 0.05), were detected on chromosomes 7 (BoPur7.1) and 9 (BoPur9.1). The subsequent high-resolution mapping of BoPur9.1 in the F2 population (n = 280) and F3 population (n = 580), with high-throughput genotyping of SNPs technology, narrowed the major anthocyanin biosynthesis QTL region to a physical distance of 73 kb, containing 14 genes. Among these genes, Bo9g174880, Bo9g174890, and Bo9g174900 showed high homology with AT5G07990 (gene encoding flavonoid 3′ hydroxylase), which was identified as a candidate gene for BoPur9.1. The expression of BoF3’H in BT 126 was significantly higher than that in SN60. Multiple biomarkers, related to these QTLs, represented potential targets of marker-assisted selection (MAS) foranthocyanin biosynthesis in broccoli. The present study provided genetic insights into the development of novel crop varieties with augmented health-promoting features and improved appearance. Full article

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

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18 pages, 3565 KiB

Open AccessArticle

Effects of Machine-Harvest Interval on Fruit Quality of Fresh Market Northern Highbush Blueberry

by Yixin Cai, Fumiomi Takeda, Brian Foote and Lisa Wasko DeVetter

Horticulturae 2021, 7(8), 245; https://doi.org/10.3390/horticulturae7080245 - 13 Aug 2021

Cited by 11 | Viewed by 3186

Abstract

Machine harvesting blueberry (Vaccinium sp.) alleviates labor costs and shortages but can reduce fruit quality. Installation of softer catching surfaces inside modified over-the-row harvesters (modified OTR) and adjusting harvest intervals may improve fruit quality and packout. The objective of this study was [...] Read more.

Machine harvesting blueberry (Vaccinium sp.) alleviates labor costs and shortages but can reduce fruit quality. Installation of softer catching surfaces inside modified over-the-row harvesters (modified OTR) and adjusting harvest intervals may improve fruit quality and packout. The objective of this study was to determine the effect of harvest interval on fruit quality of fresh market northern highbush blueberry (Vaccinium corymbosum L.) harvested using a modified OTR. ‘Liberty’ blueberry bushes were harvested by hand or using a modified OTR at 3-, 10-, and 14-day intervals in 2019 and at 7-, 11-, and 14-day intervals in 2020. Hand-harvested ‘Liberty’ had greater packout and firmness than machine-harvested fruit. Machine harvesting at the 3-day interval in 2019, and the 14-day interval in 2020 reduced packout from 70–80% to 60% and 54%, respectively. In 2019, machine harvesting at a 3-day interval overall resulted in fruit with greater firmness, higher titratable acidity (TA), and lower total soluble solids (TSS) and SS/TA, compared to other harvest intervals. In 2020, the 7-day machine-harvest interval had a greater TA and lower TSS/TA, compared to the 11- and 14-day intervals. Overall, modified OTR machine-harvest intervals can be extended to 10–11 days for fresh market northern highbush cultivars such as ‘Liberty’ grown in northwest Washington. Full article

(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)

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20 pages, 3204 KiB

Open AccessArticle

Growth Characteristics, Phytochemical Contents, and Antioxidant Capacity of Trachyandra ciliata (L.f) Kunth Grown in Hydroponics under Varying Degrees of Salinity

by Sihle Ngxabi, Muhali Olaide Jimoh, Learnmore Kambizi and Charles Petrus Laubscher

Horticulturae 2021, 7(8), 244; https://doi.org/10.3390/horticulturae7080244 - 13 Aug 2021

Cited by 11 | Viewed by 3222

Abstract

This study evaluated the effect of salinity and soilless media on the vegetative growth, phytochemicals, and antioxidant capacity of Trachyandra ciliata (wild cabbage) to develop its growth protocol and explore its potential as a natural source of secondary metabolites. Treatments consisted of different [...] Read more.

This study evaluated the effect of salinity and soilless media on the vegetative growth, phytochemicals, and antioxidant capacity of Trachyandra ciliata (wild cabbage) to develop its growth protocol and explore its potential as a natural source of secondary metabolites. Treatments consisted of different concentrations of sodium chloride (NaCl), control- 0 mM, 100 mM, 200 mM, 400 mM, while different in vitro assays were used for phytochemical and antioxidant screenings. Findings from the study showed that low salinity (100 mM) significantly increased chlorophyll content, plant height, leaf number, plant fresh weight, and production of inflorescence, particularly in Peat-Perlite-Vermiculite (PPV) medium. In contrast, the control was the most productive treatment in plant dry weight except for the inflorescence. The highest antioxidant activity was observed in 200 mM of NaCl treatment in combination with PPV medium, which also produced the highest mean values for polyphenols, while 100 mM was the best for flavonols. Therefore, T. ciliata proved to be more productive vegetatively under low salinity in combination with PPV soilless media. A combination of 200 mM + PPV treatment was also recommended for maximum production of antioxidants for T. ciliata. Full article

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

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26 pages, 448 KiB

Open AccessEditor’s ChoiceReview

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

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

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

Cited by 52 | Viewed by 10591

Abstract

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

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

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

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18 pages, 5419 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 3 | Viewed by 2986

Abstract

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

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

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

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4 pages, 670 KiB

Open AccessEditor’s ChoicePerspective

Digitalization of Clubroot Disease Index, a Long Overdue Task

by Rasha Salih and Edel Pérez-López

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

Cited by 2 | Viewed by 3431

Abstract

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

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

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

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7 pages, 223 KiB

Open AccessEditorial

Horticultural Crop Response to Different Environmental and Nutritional Stress

by Stefano Marino

Horticulturae 2021, 7(8), 240; https://doi.org/10.3390/horticulturae7080240 - 11 Aug 2021

Cited by 4 | Viewed by 2636

Abstract

Environmental conditions and nutritional stress may greatly affect crop performance. Abiotic stresses such as temperature (cold, heat), water (drought, flooding), irradiance, salinity, nutrients, and heavy metals can strongly affect plant growth dynamics and the yield and quality of horticultural products. Such effects have [...] Read more.

Environmental conditions and nutritional stress may greatly affect crop performance. Abiotic stresses such as temperature (cold, heat), water (drought, flooding), irradiance, salinity, nutrients, and heavy metals can strongly affect plant growth dynamics and the yield and quality of horticultural products. Such effects have become of greater importance during the course of global climate change. Different strategies and techniques can be used to detect, investigate, and mitigate the effects of environmental and nutritional stress. Horticultural crop management is moving towards digitized, precision management through wireless remote-control solutions, but data analysis, although a traditional approach, remains the basis of stress detection and crop management. This Special Issue summarizes the recent progress in agronomic management strategies to detect and reduce environmental and nutritional stress effects on the yield and quality of horticultural crops. Full article

(This article belongs to the Special Issue Horticultural Crop Response to Different Environmental and Nutritional Stress)

15 pages, 2583 KiB

Open AccessArticle

Comparative Growth, Photosynthetic Pigments, and Osmolytes Analysis of Hemp (Cannabis sativa L.) Seedlings under an Aeroponics System with Different LED Light Sources

by Md. Jahirul Islam, Byeong Ryeol Ryu, Md. Obyedul Kalam Azad, Md. Hafizur Rahman, Md. Soyel Rana, Chang-Won Kang, Jung-Dae Lim and Young-Seok Lim

Horticulturae 2021, 7(8), 239; https://doi.org/10.3390/horticulturae7080239 - 10 Aug 2021

Cited by 9 | Viewed by 6907

Abstract

The performance of hemp seedlings was evaluated through morphological traits, photosynthetic pigments, and osmolytes under 11 light treatments (10 LED light compositions + natural light) in an aeroponics system. The seedlings were brought under treatment at 25 days of age, where the light [...] Read more.

The performance of hemp seedlings was evaluated through morphological traits, photosynthetic pigments, and osmolytes under 11 light treatments (10 LED light compositions + natural light) in an aeroponics system. The seedlings were brought under treatment at 25 days of age, where the light intensity was 300 µmol m⁻²s⁻¹ and duration was 20 days. A higher leaf number and node number were observed in L10 (R₄:B₂:W₂:FR₁:UV₁) and L11 (R₂:B₂:G₂:W₂:FR₁:UV₁), and a higher leaf length and leaf width were recorded in the L2 (white), L3 (R₈:B₂), and L5 (R₇:B₂:FR₁) treatments. Furthermore, a higher shoot length was recorded in L3 (R₈:B₂), L6 (R₆:B₂:G₁:FR₁), and L9 (R₆:B₂:FR₁:UV₁) while roots developed more in the L1 (natural light), L5 (R₇:B₂:FR₁), and L9 (R₆:B₂:FR₁:UV₁) treatments. On the other hand, the L3 (R₈:B₂) treatment manifested higher chlorophyll a, chlorophyll b, and photosynthetic quantum yield (Fv/Fm). The hierarchical clustering and heatmap analysis revealed that higher leaf numbers and node numbers resulted in bushy plants with shorter shoots and longer roots. A negative correlation was also observed in photosynthetic traits (pigments and fluorescence) with osmolytes and root length. Importantly, the treatments L4 (R₇:B₂:G₁), L6 (R₆:B₂:G₁:FR₁), L8 (R₅:B₂:G₁:FR₁:UV₁), and L11 (R₂:B₂:G₂:W₂:FR₁:UV₁) manifested higher nodes with a higher osmolyte content, such as proline, ascorbic acid, total soluble carbohydrate, and sucrose, which may be a helpful indicator for higher branches and inflorescences, and ultimately higher cannabinoids accumulation in the plants. The approach and findings of this study could provide future research with the baseline information on optimizing the light composition to produce hemp plants with ideal phenotypes. Full article

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

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16 pages, 2951 KiB

Open AccessArticle

Effect of Drought Stress on Chlorophyll Fluorescence Parameters, Phytochemical Contents, and Antioxidant Activities in Lettuce Seedlings

by Yu Kyeong Shin, Shiva Ram Bhandari, Jung Su Jo, Jae Woo Song and Jun Gu Lee

Horticulturae 2021, 7(8), 238; https://doi.org/10.3390/horticulturae7080238 - 10 Aug 2021

Cited by 77 | Viewed by 8850

Abstract

This study monitored changes in chlorophyll fluorescence (CF), growth parameters, soil moisture content, phytochemical content (proline, ascorbic acid, chlorophyll, total phenol content (TPC), and total flavonoid content (TFC)), and antioxidant activities in 12-day-old lettuce (Lactuca sativa L.) seedlings grown under drought stress [...] Read more.

This study monitored changes in chlorophyll fluorescence (CF), growth parameters, soil moisture content, phytochemical content (proline, ascorbic acid, chlorophyll, total phenol content (TPC), and total flavonoid content (TFC)), and antioxidant activities in 12-day-old lettuce (Lactuca sativa L.) seedlings grown under drought stress (no irrigation) and control (well irrigated) treatments in controlled conditions for eight days. Measurements occurred at two-day intervals. Among ten CF parameters studied, effective quantum yield of photochemical energy conversion in PSII (Y(PSII)), coefficient of photochemical quenching (qP), and coefficient of photochemical quenching of variable fluorescence based on the lake model of PSII (qL) significantly decreased in drought-stressed seedlings from day 6 of treatment compared to control. In contrast, maximum quantum yield (F_v/F_m), ratio of fluorescence (Rfd), and quantum yield of non-regulated energy dissipation in PSII (Y(NO)) were significantly affected only at the end. All growth parameters decreased in drought-stressed seedlings compared to control. Proline started increasing from day 4 and showed ~660-fold elevation on day 8 compared to control. Chlorophyll, ascorbic acid, TPC, TFC, and antioxidant activities decreased in drought-stressed seedlings. Results showed major changes in all parameters in seedlings under prolonged drought stress. These findings clarify effects of drought stress in lettuce seedlings during progressive drought exposure and will be useful in the seedling industry. Full article

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

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13 pages, 262 KiB

Open AccessEditor’s ChoiceArticle

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

by Caroline Provost, Alexander Campbell and François Dumont

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

Cited by 10 | Viewed by 3111

Abstract

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

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

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

8 pages, 340 KiB

Open AccessArticle

Economic Impacts of Horticulture Research and Extension at MSU Coastal Research and Extension Center

by Benedict C. Posadas, Patricia R. Knight, Eric T. Stafne, Christine E. H. Coker, Gary Bachman, James DelPrince, Scott A. Langlois and Eugene K. Blythe

Horticulturae 2021, 7(8), 236; https://doi.org/10.3390/horticulturae7080236 - 10 Aug 2021

Viewed by 3185

Abstract

This paper summarizes the estimates of the total changes in sales, expenses, and income of participants of the horticulture research and extension programs at the Mississippi State University—Coastal Research and Extension Center for the past five years. Major items outline the estimation procedures [...] Read more.

This paper summarizes the estimates of the total changes in sales, expenses, and income of participants of the horticulture research and extension programs at the Mississippi State University—Coastal Research and Extension Center for the past five years. Major items outline the estimation procedures for the past five years. The average annual values were used in estimating the total economic impacts of added gross sales, expenses, and incomes of participants in horticulture events. The cumulative total impacts reach USD 8.7 million in sales, 76 jobs, USD 1.4 million in labor income, USD 2.4 million in value-added, and USD 0.4 million in local, state, and federal taxes. In addition, the total willingness to pay for the horticulture program by the adult participants reached USD 1.8 million. In comparison, the annual public spending on the horticulture program averaged USD 1.4 million, creating additional substantial economic impacts to the region. Full article

(This article belongs to the Section Outreach, Extension, and Education)

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15 pages, 2525 KiB

Open AccessArticle

Systematic Identification and Validation of Housekeeping and Tissue-Specific Genes in Allotetraploid Chenopodium quinoa

by Bing He, Hui Chen, Pibiao Shi, Fengqin Hu, Wenjing Song, Lin Meng and Yuanda Lv

Horticulturae 2021, 7(8), 235; https://doi.org/10.3390/horticulturae7080235 - 10 Aug 2021

Cited by 1 | Viewed by 2895

Abstract

Quinoa is a gluten-free food crop that contains all the essential amino acids and vitamins. The selection of proper housekeeping and tissue-specific genes is the crucial prerequisite for gene expression analysis using the common approach, real-time quantitative PCR (RT-qPCR). In this study, we [...] Read more.

Quinoa is a gluten-free food crop that contains all the essential amino acids and vitamins. The selection of proper housekeeping and tissue-specific genes is the crucial prerequisite for gene expression analysis using the common approach, real-time quantitative PCR (RT-qPCR). In this study, we identified 40 novel candidate housekeeping genes by the minimum transcript per million (TPM), coefficient of variation (CV) and maximum fold change (MFC) methods and 19 candidate tissue-specific genes by the co-expression network method based on an RNA-seq dataset that included 53 stem, leaf, flower and seed samples, as well as additional shoot and root samples under different stresses. The expression stability of 12 housekeeping and tissue-specific genes, as well as that of another two traditionally used housekeeping genes, was further evaluated using qPCR and ranked using NormFinder, BestKeeper and the comparative delta-Ct method. The results demonstrated that MIF, RGGA, VATE and UBA2B were ranked as the top four most stable candidate housekeeping genes. qPCR analysis also revealed three leaf-specific genes and five root-specific genes, but no stem-specific gene was identified. Gene Ontology (GO) enrichment analysis identified that housekeeping genes were mainly enriched in the small molecule metabolic process, organonitrogen compound metabolic process, NAD binding and ligase activity. In addition, tissue-specific genes are closely associated with the major functions of a specific tissue. Specifically, GO terms “photosynthesis” and “thylakoid” were most significantly overrepresented in candidate leaf-specific genes. The novel housekeeping and tissue-specific genes in our study will enable better normalization and quantification of transcript levels in quinoa. Full article

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

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20 pages, 7678 KiB

Open AccessArticle

Physiology Response and Resistance Evaluation of Twenty Coconut Germplasm Resources under Low Temperature Stress

by Chengxu Sun, Ruining Zhang, Zhouyu Yuan, Hongxing Cao and Jerome Jeyakumar John Martin

Horticulturae 2021, 7(8), 234; https://doi.org/10.3390/horticulturae7080234 - 9 Aug 2021

Cited by 12 | Viewed by 3737

Abstract

Coconut (Cocos nucifera L.) is a tropical evergreen crop with high economic value. Low temperature is one of the main environmental factors that limit coconut productivity. Therefore, it is necessary and significant to research the growth trend and physiological changes of coconuts [...] Read more.

Coconut (Cocos nucifera L.) is a tropical evergreen crop with high economic value. Low temperature is one of the main environmental factors that limit coconut productivity. Therefore, it is necessary and significant to research the growth trend and physiological changes of coconuts under a low temperature environment. In this study, the physiological response of 20 coconut germplasm resources is presented in an integrated perspective to provide a holistic view of the behavior of coconut trees facing cold stress under four temperature conditions (25 °C, 15 °C, 10 °C, 5 °C). It was shown that low temperature would lead to the increase of relative electrical conductivity, MDA content, soluble protein content, and proline content. In addition, the activities of defense enzymes (SOD, POD, CAT, APX) were increased to resist the cold environment. In a comprehensive analysis, it was revealed that coconut germplasms with high cold resistance, such as C2, C7, and C10 as well as POD activity, proline content, and soluble protein content, were defined as representatives for coconut cold resistance evaluation. Through the exploration of osmotic adjustment substances and defense enzymes, the breeding and quality improvement of cold-resistant coconut varieties could be promoted. As a result, understanding the physiological response and tolerance mechanisms of coconuts to low temperature stress was essential, as this perception may serve as the foundation for coconut resistance evaluation, cultivation, and breeding. Full article

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

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22 pages, 20771 KiB

Open AccessArticle

Foliar Application of ZnSO₄ and CuSO₄ Affects the Growth, Productivity, and Fruit Quality of Washington Navel Orange Trees (Citrus sinensis L.) Osbeck

by Sherif Fathy El-Gioushy, Rokayya Sami, Amina A. M. Al-Mushhin, Hanan M. Abou El-Ghit, Mohamed S. Gawish, Khadiga Ahmed Ismail and Reda M. Y. Zewail

Horticulturae 2021, 7(8), 233; https://doi.org/10.3390/horticulturae7080233 - 9 Aug 2021

Cited by 10 | Viewed by 3943

Abstract

The goal of this study was to examine how to improve the vegetative growth, nutritional status, productivity, and fruit quality of Washington navel orange trees by examining the effect of foliar application of ZnSO₄ (0, 300, and 600 mg/L) solutions in combination [...] Read more.

The goal of this study was to examine how to improve the vegetative growth, nutritional status, productivity, and fruit quality of Washington navel orange trees by examining the effect of foliar application of ZnSO₄ (0, 300, and 600 mg/L) solutions in combination with CuSO₄ (0, 200, and 400 mg/L) solutions on Washington navel orange trees, which were 11 years old and grown in clay loam soil with a surface irrigation system. The results showed that all the investigated measurements responded specifically to each investigated factor. ZnSO₄ elicited a stronger and more effective response than CuSO₄. Nonetheless, the response varied only slightly or moderately from one measurement to the next. In terms of the interaction effect between ZnSO₄ and CuSO₄ concentrations, the effect of each investigated factor was directly reflected in its combinations, with ZnSO₄ (600 mg/L) and CuSO₄ (200 and 400 mg/L) being the most effective for the majority of the measurements under consideration. When the highest level of ZnSO₄ was combined with the highest level of CuSO₄, the highest values for the various vegetative growth parameters shoot length and diameter, number of leaves per shoot, leaf area, and total assimilation area per shoot were obtained. As a result, the nutritional status (the highest total leaf chlorophyll and leaf mineral contents) was significantly coupled with the treatment of 600 mg/L ZnSO₄ in combination with 400 mg/L CuSO₄. Moreover, the combinations of the highest ZnSO₄ concentration (600 mg/L) and CuSO₄ concentration (400 mg/L) exhibited the greatest statistical values of the measurements of fruiting aspects as well as fruit quality. Consequently, it can be recommended that using 600 mg/L ZnSO₄ in combination with 400 mg/L CuSO₄ as a foliar spray on monthly basis during the period from March to July could be safely recommended under similar environmental conditions and horticulture practices adopted in the present experiment. Full article

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13 pages, 3271 KiB

Open AccessArticle

HPLC Characterization of Phytochemicals and Antioxidant Potential of Alnus nitida (Spach) Endl.

by Javed Khan, Abdul Majid, Nausheen Nazir, Mohammad Nisar, Atif Ali Khan Khalil, Muhammad Zahoor, Mohammad Ihsan, Riaz Ullah, Ahmed Bari and Abdul Bari Shah

Horticulturae 2021, 7(8), 232; https://doi.org/10.3390/horticulturae7080232 - 8 Aug 2021

Cited by 7 | Viewed by 4247

Abstract

Antioxidants isolated from plants have attracted the interest of clinicians and common people to be used for systemic uses rather than synthetic antioxidants because of their active role in maintaining human health with minimal side effects. Alnus nitida (Spach) Endl. is an important [...] Read more.

Antioxidants isolated from plants have attracted the interest of clinicians and common people to be used for systemic uses rather than synthetic antioxidants because of their active role in maintaining human health with minimal side effects. Alnus nitida (Spach) Endl. is an important medicinal plant native to western Himalaya and is widely distributed throughout Pakistan. The present study evaluates the phytochemical composition of this plant using HPLC along with the total content of phenolics and flavonoids. The antioxidant activities were determined following the Brand William assay. The methanolic extract (Met. Ext) of leaves, stem bark, seeds, and roots of A. nitida were used to scavenge synthetic free radicals such as DPPH and ABTS. From HPLC fingerprinting of the A. nitida selected portion, six possible phytochemicals were confirmed. Among the identified phytochemicals, there are six compounds (malic acid, chlorogenic acid, epigallocatechin gallate, quercetin, ellagic acid and pyrogallol) in the leaves of A. nitida, three (epigallocatechin gallate, ellagic acid, and pyrogallol) in the stem bark, six in the seeds (malic acid, vitamin C, epigallocatechin gallate, quercetin, ellagic acid, and pyrogallol), and five (malic acid, epigallocatechin gallate, quercetin, and ellagic acid) in root. Comparatively, the highest antioxidant potentials were recorded for the leaves extract (IC₅₀ of 340 and 645 µg/mL against DPPH and ABTS, respectively). The percentages of inhibition were compared with the positive control ascorbic acid, which produced an IC₅₀ value of 60 μg/mL each against the free radicals DPPH and ABTS. The highest phenolics (43.81 mg GAE/g sample) were found in the roots, while the highest flavonoid contents (53.25 mg QE/g sample) were in the leaves. It was assumed that observed antioxidant potentials of the tested plant might be due to their phytochemicals confirmed through HPLC, and thus, this plant may be a valuable candidate in treating oxidative stress and related disorders. However, further investigations are needed to isolate responsible components in pure from. Furthermore, toxicological effects in in vivo animal models are also needed to confirm the results observed in this study. Full article

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

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12 pages, 12215 KiB

Open AccessArticle

The Isolation and Identification of Anthocyanin-Related GSTs in Chrysanthemum

by Yajing Li, Xiaofen Liu, Fang Li, Lili Xiang and Kunsong Chen

Horticulturae 2021, 7(8), 231; https://doi.org/10.3390/horticulturae7080231 - 7 Aug 2021

Cited by 10 | Viewed by 3775

Abstract

Anthocyanin is the crucial pigment for the coloration of red chrysanthemum flowers, which synthesizes in the cytosol and is transported to the vacuole for stable storage. In general, glutathione S-transferases (GSTs) play a vital role in this transport. To date, there is no [...] Read more.

Anthocyanin is the crucial pigment for the coloration of red chrysanthemum flowers, which synthesizes in the cytosol and is transported to the vacuole for stable storage. In general, glutathione S-transferases (GSTs) play a vital role in this transport. To date, there is no functional GST reported in chrysanthemums. Here, a total of 94 CmGSTs were isolated from the chrysanthemum genome, with phylogenetic analysis suggesting that 16 members of them were clustered into the Phi subgroup which was related to anthocyanin transport. Among them, the expression of CmGST1 was positively correlated with anthocyanin accumulation. Protein sequence alignment revealed that CmGST1 included anthocyanin-related GST-specific amino acid residues. Further transient overexpression experiments in tobacco leaves showed that CmGST1 could promote anthocyanin accumulation. In addition, a dual-luciferase assay demonstrated that CmGST1 could be regulated by CmMYB6, CmbHLH2 and CmMYB#7, which was reported to be related to anthocyanin biosynthesis. Taken together, we suggested that CmGST1 played a key role in anthocyanin transport and accumulation in chrysanthemums. Full article

(This article belongs to the Special Issue Advances in Horticultural Crops Comparative and Functional Genomics)

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