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Horticulturae, Volume 9, Issue 6 (June 2023) – 115 articles

Cover Story (view full-size image): Hybridization is a widely used technique for generating plant diversity. Therefore, predicting the success of interspecific hybridization can help breeders to plan their breeding programmes effectively. Using various criteria and considering parental differences, this research aimed to predict the success of crosses based on the genetic distance between parents in Geranium. A formula was obtained that breeders can use to predict the success of their crosses. This prediction tool will allow breeders to determine the number of crosses needed to achieve a given seed yield. View this paper
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12 pages, 1949 KiB  
Article
Fruit Phenology of Two Hazelnut Cultivars and Incidence of Damage by Halyomorpha halys in Treated and Untreated Hazel Groves
by Flavia de Benedetta, Matteo Giaccone, Feliciana Pica, Maria Tiziana Lisanti, Francesco Vinale, David Turrà, Gianpaolo Maria Giacca and Umberto Bernardo
Horticulturae 2023, 9(6), 727; https://doi.org/10.3390/horticulturae9060727 - 20 Jun 2023
Cited by 1 | Viewed by 1200
Abstract
Over the past decade, Halyomorpha halys has become one of the main threats to hazelnut production. Its trophic activity makes kernels inedible due to strongly detrimental effects on the organoleptic quality. Its management in Italy is still tricky due to the lack of [...] Read more.
Over the past decade, Halyomorpha halys has become one of the main threats to hazelnut production. Its trophic activity makes kernels inedible due to strongly detrimental effects on the organoleptic quality. Its management in Italy is still tricky due to the lack of effective native biocontrol agents and authorized and effective insecticides. A field test was performed on San Giovanni (SG) and Tonda Romana (TR) cultivars (early and late ripening, respectively) to assess the intensity of cimiciato damage with different pest management approaches (no insecticide and integrated pest management, IPM). Moreover, phenological analysis of fruits and the monitoring of stink bug species by traps and plant beating were carried out. In the untreated plots, the SG cv showed a higher cimiciato incidence with respect to the late TR cv (40% SG–NI vs. 23% TR–NI). This was probably due to the different phenological phases in which stink bugs injured the fruits. In fact, stink bug bites provoke different kinds of injuries (blanks, shriveled, and cimiciato) according to the fruit’s development period. Indeed, in the period of highest insect occurrence in the field, the fruits of the early cv (SG) were in kernel expansion, a phenological phase in which bug injuries are more likely in cimiciato defects. Lastly, the IPM did not provide sufficient fruit protection (19% SG–IPM vs. 11% TR–IPM). The interaction between the phenological development of hazelnuts and the brown marmorated stink bug represents a critical aspect in understanding and implementing effective strategies for controlling this key pest on hazelnut trees. Full article
(This article belongs to the Special Issue New Challenge of Horticultural Crops under Climate Change)
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12 pages, 3778 KiB  
Article
Genetic Diversity and Population Structure of a Longan Germplasm in Thailand Revealed by Genotyping-By-Sequencing (GBS)
by Kanamon Riangwong, Chatree Saensuk, Mutiara K. Pitaloka, Reajina Dumhai, Vinitchan Ruanjaichon, Theerayut Toojinda, Samart Wanchana and Siwaret Arikit
Horticulturae 2023, 9(6), 726; https://doi.org/10.3390/horticulturae9060726 - 20 Jun 2023
Cited by 1 | Viewed by 1210
Abstract
Longan (Dimocarpus longan Lour.) is grown commercially in many countries, including China, Thailand, the Philippines, Malaysia, Vietnam, India, Australia, and Hawaii. Thailand is the second largest producer and largest exporter of longan in the world. Currently, there is limited information on the [...] Read more.
Longan (Dimocarpus longan Lour.) is grown commercially in many countries, including China, Thailand, the Philippines, Malaysia, Vietnam, India, Australia, and Hawaii. Thailand is the second largest producer and largest exporter of longan in the world. Currently, there is limited information on the genetic background, population structure, and genetic relationships among longan cultivars in Thailand. In this study, a total of 50 longan accessions from a community-based germplasm collection in Thailand were analyzed using 10,619 SNPs from genotyping-by-sequencing (GBS). Based on the results of STRUCTURE analysis, 43 accessions were classified into 4 subpopulations, and the other 7 accessions were found to contain admixed genotypes. Based on UPGMA clustering analysis and PCoA analysis, the longan accessions could be divided into six major groups consistent with those identified by STRUCTURE. A relatively high degree of genetic variation was observed among the longan accessions, as quantified by the expected heterozygosity (He = 0.308). AMOVA results showed that 74% and 26% of the total variation occurred between and within populations, respectively. Obvious genetic differentiation between populations (FST = 0.25) was observed. The results of this study are useful for managing longan germplasm and may facilitate the genetic improvement of longan. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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12 pages, 2122 KiB  
Article
Silver Nano Chito Oligomer Hybrid Solution for the Treatment of Citrus Greening Disease (CGD) and Biostimulants in Citrus Horticulture
by Pakpoom Vatcharakajon, Ampol Sornsaket, Khuanjarat Choengpanya, Chanthana Susawaengsup, Jirapong Sornsakdanuphap, Nopporn Boonplod, Prakash Bhuyar and Rapeephun Dangtungee
Horticulturae 2023, 9(6), 725; https://doi.org/10.3390/horticulturae9060725 - 20 Jun 2023
Cited by 1 | Viewed by 1426
Abstract
Citrus greening disease (CGD), or Huanglongbing (HLB), is principal in Citrus farming because of its severe damage, decreased yield, poor quality of fruit, and frequent disappearance before harvest. Present research blended silver nanoparticles (AgNPs) colloid with chitooligomers and monomers (COAMs) to create the [...] Read more.
Citrus greening disease (CGD), or Huanglongbing (HLB), is principal in Citrus farming because of its severe damage, decreased yield, poor quality of fruit, and frequent disappearance before harvest. Present research blended silver nanoparticles (AgNPs) colloid with chitooligomers and monomers (COAMs) to create the composites referred to as a “hybrid solution”. The hybrid solution has been synthesized for antimicrobial effects and plant growth stimulation. The hybrid solution was applied to cure the CGD, which was then tested using the results of the iodine test kit. Study results revealed that the mechanism for antibacterial properties is efficient and leads to cell death by silver ions (positive charge) attached to the cell wall of pathogens (negative charge). COAMs increase AgNPs’ ability to adhere to negatively charged bacterial cytoplasmic membranes and amplify their electrostatic interaction. There are synergistic antibacterial effects of AgNPs–COAMs. The findings reveal a notable increase in the shoot length of leaves which may be the reason for the growth stimulation function of the hybrid solution due to the properties of COAMs as a biostimulant. The hybrid solution-treated trees yielded around 104.50 ± 4.56 kg of fruits by the trunk or foliar application. Citrus fruits did not show the presence of any silver residues, as displayed by the results of the accumulation test. Compared to conventional ampicillin, the hybrid treatment of CGD was significantly more cost-effective, increased productivity, and had minor accumulation. The acquired results may also be applied to further plant disease treatment. Full article
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15 pages, 3483 KiB  
Review
SO2-Generating Pads and Packaging Materials for Postharvest Conservation of Table Grapes: A Review
by Aline Cristina de Aguiar, Maíra Tiaki Higuchi, Fábio Yamashita and Sergio Ruffo Roberto
Horticulturae 2023, 9(6), 724; https://doi.org/10.3390/horticulturae9060724 - 20 Jun 2023
Cited by 3 | Viewed by 1929
Abstract
Table grapes are one of the leading fruit species cultivated in several countries due to their distinguishing sensory and nutritional properties. However, grapes are a non-climacteric fruit with relatively low physiological activity after harvest, and they are highly perishable due to gray mold [...] Read more.
Table grapes are one of the leading fruit species cultivated in several countries due to their distinguishing sensory and nutritional properties. However, grapes are a non-climacteric fruit with relatively low physiological activity after harvest, and they are highly perishable due to gray mold caused by Botrytis cinerea as well to mass loss, berry softening, color degradation, and dehydration and darkening of the stem. To avoid all these difficulties, several packaging materials are used during cold storage to keep table grapes fresh and healthy for consumers. Proper packaging and cold storage combined can extend the shelf life of high-quality bunches by protecting them from mechanical injuries and decays during transportation and storage. In recent years, several packaging materials have been developed to be used for domestic and export markets, especially those when the conservation of table grapes has to be extended for several weeks or even months. This review addresses the main recent packaging materials for postharvest conservation of table grapes during cold storage, including SO2-generating pads, perforated plastic, and bio-based liners. Full article
(This article belongs to the Special Issue Advances in Postharvest Disease Management in Fruits and Vegetables)
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7 pages, 511 KiB  
Communication
Innovative Tools for the Nitrogen Fertilization Traceability of Organic Farming Products
by Simona Fabroni, Luana Bontempo, Gabriele Campanelli, Stefano Canali and Francesco Montemurro
Horticulturae 2023, 9(6), 723; https://doi.org/10.3390/horticulturae9060723 - 20 Jun 2023
Cited by 1 | Viewed by 1115
Abstract
In the last decades, consumers have become increasingly interested in organic products, and they strongly demand reliability in the traceability of the organic products they buy and eat. Several research methods have been developed in the last decades to study inexperienced and reliable [...] Read more.
In the last decades, consumers have become increasingly interested in organic products, and they strongly demand reliability in the traceability of the organic products they buy and eat. Several research methods have been developed in the last decades to study inexperienced and reliable systems and to assess the authenticity of products obtained using organic cultivation practices. The monitoring of some chemical compounds, originating from primary and/or secondary metabolism, in horticultural organic and conventional products has shown the diversity generated using the two production approaches. The difference in fertilization practices has been also shown to have an effect on the isotopic distribution of some elements, with particular reference to nitrogen. An integrated system is proposed to evaluate the validity of organic goods using collected isotopic data and other chemical and biological parameters. This approach is intended to be coupled to the application of chemometric multivariate analysis on quality and nutraceutical parameters combined with isotopic data. Indeed, this will give the opportunity to discriminate organic from conventional products based on different isotopic signatures, due to the different nitrogenous sources, combined with the qualitative profile of the crops, which are significantly affected by the different agronomic treatments. The main perspectives of the presented integrated approach, based on the combined use of chemometric and analytical tools, are linked to the feasibility of applying a reliable system for traceability. This will authenticate productions obtained using organic fertilizers (organic agriculture) with respect to those obtained with the use of synthetic fertilizers (conventional agriculture), protect and valorize virtuous farmers and support political stakeholders and decision-makers to counteract food fraud. Full article
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16 pages, 1165 KiB  
Article
Physiological and Molecular Screening of High Temperature Tolerance in Okra [Abelmoschus esculentus (L.) Moench]
by Shahnoosh Hayamanesh, Richard Trethowan, Tariq Mahmood, Nabil Ahmad and Claudia Keitel
Horticulturae 2023, 9(6), 722; https://doi.org/10.3390/horticulturae9060722 - 19 Jun 2023
Cited by 1 | Viewed by 1241
Abstract
Okra is a vegetable crop adapted to summer temperatures, but heat stress has been shown to reduce its growth and productivity. We measured physiological traits of 104 okra genotypes in response to high temperature, augmented by the molecular characterization of selected genotypes to [...] Read more.
Okra is a vegetable crop adapted to summer temperatures, but heat stress has been shown to reduce its growth and productivity. We measured physiological traits of 104 okra genotypes in response to high temperature, augmented by the molecular characterization of selected genotypes to identify parents for crossing. Genotypes were exposed to a short heat shock (45 °C, 4 h) in a controlled environment, followed by the assessment of chlorophyll fluorescence (Fv/Fm, Fv′/Fm′) and stomatal conductance (gs). DNA was isolated from all genotypes using a modified CTAB method with additional PVP and RNase, and the amplification of 8 polymorphic SSR markers was used to generate a dendrogram. This preliminary screening identified 33 polymorphic genotypes with less than 50% genetic similarity and contrasting Fv′/Fm′ and gs responses. More detailed physiological measurements (Fv/FmFv′/Fm′, gs, photosynthesis (A), efficiency of the open reaction centre (ΦPSII), and electrolyte leakage (EL)) were conducted after exposure to 45 °C for 6 h and compared to the control (30 °C). EL did not significantly increase in the heat treatment; in contrast, there were significant genotype and treatment effects observed for fluorescence (Fv/Fm, Fv′/Fm′) and photosynthetic parameters (A, ΦPSII, gs). In conclusion, cell membranes in okra remained unaffected after short periods of heat stress, whereas the ranking of differences of measured physiological traits (∆) between control and heat-treated plants (∆Fv′/Fm′, ∆Fv′/Fm′, ∆A, ∆ΦPSII, ∆gs) was indicative of genotype sensitivity to heat. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
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20 pages, 1718 KiB  
Article
Effects of Organic and Conventional Cultivation on Composition and Characterization of Two Citrus Varieties ‘Navelina’ Orange and ‘Clemenules’ Mandarin Fruits in a Long-Term Study
by Alfons Domínguez-Gento, Rosita Di Giorgi, María Dolores García-Martínez and María Dolores Raigón
Horticulturae 2023, 9(6), 721; https://doi.org/10.3390/horticulturae9060721 - 19 Jun 2023
Viewed by 1298
Abstract
A transition towards an organic food system is taking place around the world. This process is favored by growing consumer demand, who associate organic crops with being healthier, tastier, and safer for the environment than conventional crops. Citrus is one of the most [...] Read more.
A transition towards an organic food system is taking place around the world. This process is favored by growing consumer demand, who associate organic crops with being healthier, tastier, and safer for the environment than conventional crops. Citrus is one of the most widely produced crops worldwide and has important socio-economic and cultural significance in the Mediterranean area. The aim of this work is twofold; on the one hand, it reveals the variability of a set of physical–chemical and nutritional quality parameters of two citrus fruit varieties, ‘Navelina’ oranges and ‘Clemenules’ mandarins, from organic and conventional production in a long-term study. On the other hand, taking advantage of the large number of results, a model is proposed that allows the successful differentiation of citrus fruits from organic and conventional production and a tool that allows predicting the production system of citrus fruits. The results suggest that organically produced citrus fruits do not generate differences in terms of external aspects, providing fruits that are acceptable to the market. Organic production techniques influenced the lower peel content and higher pulp and juice content in ‘Navelina’ orange and ‘Clemenules’ mandarin fruits and led to a greater ability to synthesize vitamin C in the juice, more essential oils in the skin, and higher seed numbers, although in all cases, the fruits can be classified as having low seed numbers. Two discriminating equations were obtained that use easy-to-measure parameters to successfully classify organic citrus fruits. The classification and prediction models obtained constitute useful tools to help in the control of the purity/authenticity of organic citrus fruits. Full article
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15 pages, 1214 KiB  
Review
Apricot Rootstocks with Potential in Hungary
by Edina Mendelné Pászti, Geza Bujdoso, Sezai Ercisli, Karoly Hrotkó and Ákos Mendel
Horticulturae 2023, 9(6), 720; https://doi.org/10.3390/horticulturae9060720 - 19 Jun 2023
Cited by 4 | Viewed by 1893
Abstract
In the last five decades, the use of rootstocks and scions has changed, along with their systems of cultivation. Associated with climate change, fruit trees face new ecological and phytopathological challenges. Rootstocks affect the generative and vegetative performance of a scion, such as [...] Read more.
In the last five decades, the use of rootstocks and scions has changed, along with their systems of cultivation. Associated with climate change, fruit trees face new ecological and phytopathological challenges. Rootstocks affect the generative and vegetative performance of a scion, such as productivity, span of nonbearing period, growth vigor, shelf-life and quality of fruits. According to a recent study, they also affect the frost tolerance of floral buds. Several traits of rootstocks facilitate the growth of a grafted tree under different climatic and soil conditions. Due to the high risks of cultivation, it is extremely important to determine which rootstocks are suitable for successful apricot production. Origin, effects on vegetative and generative traits, tolerance, resistance and adaptability of rootstocks are summarized in this review to select suitable rootstock for apricot cultivars under Hungarian conditions. Full article
(This article belongs to the Collection New Insights into Developmental Biology of Fruit Trees)
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13 pages, 2891 KiB  
Article
Field Performance of ‘Valencia’ Sweet Orange Trees Grafted onto Pummelo Interstocks and Swingle Citrumelo Rootstocks under Huanglongbing (HLB) Endemic Conditions
by Manjul Dutt, Lamiaa M. Mahmoud and Jude W. Grosser
Horticulturae 2023, 9(6), 719; https://doi.org/10.3390/horticulturae9060719 - 19 Jun 2023
Viewed by 1406
Abstract
Interstocks have been used in fruit tree cultivation to regulate tree size and improve fruit production and quality. In this study, several Huanglongbing (HLB)-tolerant open-pollinated pummelo interstock candidates were evaluated as interstocks between the Swingle rootstock and the ‘Valencia’ scion, with Swingle serving [...] Read more.
Interstocks have been used in fruit tree cultivation to regulate tree size and improve fruit production and quality. In this study, several Huanglongbing (HLB)-tolerant open-pollinated pummelo interstock candidates were evaluated as interstocks between the Swingle rootstock and the ‘Valencia’ scion, with Swingle serving as the control interstock. After 5 years in the field, most trees did not exhibit visual HLB symptoms, although the trees were infected with HLB, and the CaLas Ct values in the ‘Valencia’ leaves of the different interstock treatments ranged between 25.88 and 27.82. Although the foliar chlorophyll content among the interstock treatments was not highly significant (p-value = 0.0313), the foliar starch content was significantly different (p-value = 0.0018). ‘Valencia’ grafted onto 5-1-99-3 and HBJL-4 interstocks (both open pollinated seedlings of the Hirado Buntan pummelo) exhibited the highest total phenolic compound (TPC) levels (46.44 and 46.36 mg gallic acid g−1 FW). Transcripts of CsPR1 and CsPR2, two pathogenesis-related (PR) genes, were upregulated in ‘Valencia’ grafted onto open pollinated seedling selections of the red shaddock pummelo, Liang Ping Yau pummelo, and Hirado Buntan pummelo compared with ‘Valencia’ grafted onto Swingle. All interstocks influenced the tree growth rate and improved canopy volume in the field compared to the control trees without any interstocks (p-value = 0.0085). The 5-4-99-7 (red shaddock pummelo) and 8-1-99-1B (Liang Ping Yau pummelo) interstock trees had the highest canopy volume among all the treatments. We propose, based on our current results, that HLB-tolerant citrus accessions, when judiciously used as interstocks, may enhance plant defense and provide increased HLB tolerance to susceptible scions. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
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11 pages, 1995 KiB  
Article
Effect of Oxalic Acid Treatments and Modified Atmosphere Packaging on the Quality Attributes of Rocket Leaves during Different Storage Temperatures
by Derya Erbaş
Horticulturae 2023, 9(6), 718; https://doi.org/10.3390/horticulturae9060718 - 19 Jun 2023
Cited by 2 | Viewed by 1028
Abstract
The effects of combinations of oxalic acid (OA) treatment with modified atmosphere packaging on the quality and biochemical content changes of rocket (Eruca sativa Mill. cv. Bengi) leaves were examined. After harvest, selected leaves were dipped into an aqueous solution containing different [...] Read more.
The effects of combinations of oxalic acid (OA) treatment with modified atmosphere packaging on the quality and biochemical content changes of rocket (Eruca sativa Mill. cv. Bengi) leaves were examined. After harvest, selected leaves were dipped into an aqueous solution containing different concentrations of oxalic acid (0-control, 0.25 mM, 0.5 mM, and 1 mM) for 1 min. Treated samples were dried and placed in modified atmosphere packages. Treated rockets were stored at two different temperatures (0 °C and 10 °C) and 90 ± 5% relative humidity conditions for 10 days. Leaves were analyzed at 2-day intervals for some quality and biochemical parameters during storage. OA-treated leaves were greener than those of the control group. At the end of the storage, high doses (1 mM) of OA applications successfully suppressed the respiration rate (0 °C: 63.12 mL CO2 kg−1 h−1, 10 °C: 78.09 mL CO2 kg−1 h−1) and retarded the weight loss (0 °C: 0.14%, 10 °C: 0.49%) and color discoloration (0 °C: ∆E 7.23, 10 °C: ∆E 8.34) of rocket leaves. In addition, OA treatments decreased the vitamin C losses and chlorophyll degradation. In conclusion, rocket leaves could be stored at 0 °C for 8–9 days with 1 mM OA treatment and 6 days with the control treatment and at 10 °C for 6–7 days with 1 mM OA treatment and 4 days with the control (C) treatment with a minimum quality loss under MAP conditions. Full article
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18 pages, 4214 KiB  
Article
Comparative Analysis of GRAS Genes in Six Cucurbitaceae Species Provides Insights into Their Evolution and Function
by Qiqi Zhang, Cui Wang, Jun He, Yuanchao Xu, Hongbo Li, Tianshu Sun, Sen Chai, Hongjia Xin, Kuipeng Xu, Shan Mou and Zhonghua Zhang
Horticulturae 2023, 9(6), 717; https://doi.org/10.3390/horticulturae9060717 - 18 Jun 2023
Viewed by 961
Abstract
The Cucurbitaceae family comprises economically valuable vegetables such as cucumber, melon, and pumpkin. GRAS proteins, which are crucial transcription factors, play diverse roles in plant growth and development. However, comparative investigations of GRAS proteins across Cucurbitaceae species are limited. Here, we identified 241 [...] Read more.
The Cucurbitaceae family comprises economically valuable vegetables such as cucumber, melon, and pumpkin. GRAS proteins, which are crucial transcription factors, play diverse roles in plant growth and development. However, comparative investigations of GRAS proteins across Cucurbitaceae species are limited. Here, we identified 241 GRAS family genes in six cucurbit crops. The number of GRAS genes in cucumber, melon, wax gourd, watermelon, and bottle gourd ranged from 36 to 37, while the pumpkin genome contained 57 GRAS genes, possibly due to a recent whole-genome duplication. We classified cucurbit GRAS genes into 16 subfamilies and identified species-specific motifs and specific-expression patterns in the SCLB and RAD1 subfamilies. Notably, we identified 38 tissue-specific expressed genes, particularly fruit-specific genes potentially involved in fruit development. Additionally, we predicted the role of GRAS genes in regulating hypocotyl elongation under weak or dark light conditions in cucurbit plants. These findings enhance our understanding of the characteristics, evolution, and potential functions of GRAS genes in six cucurbit crops, providing valuable resources for genetic research in the Cucurbitaceae family as well as important agronomic traits. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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19 pages, 4031 KiB  
Article
Trichoderma viride Isolate Tvd44 Enhances Potato Growth and Stimulates the Defense System against Potato Virus Y
by Dalia G. Aseel, Seham A. Soliman, Abdulaziz A. Al-Askar, Amr Elkelish, Toufic Elbeaino and Ahmed Abdelkhalek
Horticulturae 2023, 9(6), 716; https://doi.org/10.3390/horticulturae9060716 - 17 Jun 2023
Cited by 1 | Viewed by 1383
Abstract
Biological treatments may be employed to combat viral plant infections. In this study, Trichoderma viride was applied as a biocontrol agent to enhance the systemic resistance of potato plants against potato virus Y (PVY). T. viride isolate Tvd44 (OQ991378) was isolated and molecularly [...] Read more.
Biological treatments may be employed to combat viral plant infections. In this study, Trichoderma viride was applied as a biocontrol agent to enhance the systemic resistance of potato plants against potato virus Y (PVY). T. viride isolate Tvd44 (OQ991378) was isolated and molecularly characterized before being used as an agent against PVY. The foliar application of Tvd44 on PVY-inoculated potatoes significantly promoted plant growth, height, roots, and number of leaves. Results also showed that the levels of peroxidase (POX), polyphenol oxidase (PPO), total proteins, and chlorophyll increased in potato leaves 21 days post-inoculation compared to untreated plants. Results of qPCR assays conducted on Tvd44-treated plants exhibited a reduction in PVY-CP accumulation levels up to 18.76-fold compared to untreated plants (101.82-fold). qPCR results also showed that defense-related genes (PR-1, POD, PAL, CHS, and HQT) were highly expressed in all Tvd44-treated plants. Three compounds: thiocarbamic acid, N,N-dimethyl, S-1,3-diphenyl-2-butenyl ester; 1,1-dicyano-2-methyl-4-(p-cyanophenyl) propane; and trans-[(2,3-diphenylcyclopropyl)methyl] phenyl sulfide were the most abundant compounds detected in the ethyl acetate extract of Tvd44-culture filtrate using GC–MS analysis. Our finding supports the efficacy of T. viride isolate Tvd44 as a potential agent that can successfully control PVY infections in potatoes and increase the productivity of the crop. Full article
(This article belongs to the Section Plant Pathology and Disease Management (PPDM))
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10 pages, 3359 KiB  
Article
Coating of Layer-by-Layer Assembly Based on Chitosan and CMC: Emerging Alternative for Quality Maintenance of Citrus Fruit
by Chenyu Niu, Lingling Liu, Amr Farouk, Cunkun Chen and Zhaojun Ban
Horticulturae 2023, 9(6), 715; https://doi.org/10.3390/horticulturae9060715 - 17 Jun 2023
Cited by 2 | Viewed by 1256
Abstract
Citrus fruits are susceptible to microbial infection during storage and transportation, leading to weight loss, quality deterioration and even physiological decay. In this study, a layer-by-layer (LbL) self-assembly edible coating based on chitosan and Sodium carboxymethyl cellulose (CMC) was prepared using electrostatic deposition. [...] Read more.
Citrus fruits are susceptible to microbial infection during storage and transportation, leading to weight loss, quality deterioration and even physiological decay. In this study, a layer-by-layer (LbL) self-assembly edible coating based on chitosan and Sodium carboxymethyl cellulose (CMC) was prepared using electrostatic deposition. Postharvest citrus fruits (Citrus reticulate cv. ‘Chunxiang’) were coated either with the LbL coating, which exhibited an increased transmission rate of water vapor, or with single chitosan coating. The data of some physiological indexes of citrus coated with LbL coating and single coating were compared after being stored at 13 ± 2 °C and at relative humidity (RH) at 80–85% (shelf-life condition) for 10 days. Results demonstrated that the LbL deposited coating was effective at maintaining morphological and microstructural attributes, increasing the surface brightness, firmness and the content of titratable acid and ascorbic acid, as well as reducing the weight loss after storage by about 0.8%. Results in the present study indicated that the LbL edible coating could have the potential to maintain postharvest citrus quality during storage. Full article
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12 pages, 3091 KiB  
Article
Induced Defense in Avocado Fruits Mediated by Secondary Metabolites Produced by Bacillus atrophaeus B5
by Miriam del Carmen Bañuelos-González, Esther Angélica Cuéllar-Torres, Ulises Miguel López-García, Efigenia Montalvo-González, Rosa Isela Ortiz-Basurto, Selene Aguilera-Aguirre and Alejandra Chacón-López
Horticulturae 2023, 9(6), 714; https://doi.org/10.3390/horticulturae9060714 - 17 Jun 2023
Viewed by 1013
Abstract
Biocontrol agents are an environmentally friendly alternative to chemical pesticides against phytopathogens. The effectiveness of metabolites produced by Bacillus atrophaeus B5 for controlling anthracnose produced by Colletotrichum gloeosporioides in harvested fruit and the possible action mechanisms have been studied. Avocado fruit treated with [...] Read more.
Biocontrol agents are an environmentally friendly alternative to chemical pesticides against phytopathogens. The effectiveness of metabolites produced by Bacillus atrophaeus B5 for controlling anthracnose produced by Colletotrichum gloeosporioides in harvested fruit and the possible action mechanisms have been studied. Avocado fruit treated with metabolites reduced 54% of anthracnose incidence and nearly 70% of the lesion than untreated fruit. The treatment enhanced the activities of peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase. Additionally, the transcription of PAL and EIN3-like genes related to defense were increased. These results suggest that metabolites produced by B. atrophaeus B5 enhance disease resistance against C. gloeosporioides in avocado fruit. In the fruit, the induced resistance is related to the priming of defense responses. Metabolites in the cell-free supernatant could also be a potential biological preservative for avocado protection. Full article
(This article belongs to the Special Issue Advances in Postharvest Disease Management in Fruits and Vegetables)
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19 pages, 1502 KiB  
Article
Differences in Saprophytic Growth, Virulence, Genomes, and Secretomes of Ilyonectria robusta and I. mors-panacis Isolates from Roots of American Ginseng (Panax quinquefolius)
by Behrang Behdarvandi, Tom Hsiang, Moez Valliani and Paul H. Goodwin
Horticulturae 2023, 9(6), 713; https://doi.org/10.3390/horticulturae9060713 - 17 Jun 2023
Viewed by 948
Abstract
A comparison of the virulence, saprophytic growth, and genomes of 12 isolates of Ilyonectria mors-panacis and 4 isolates of I. robusta from Canada pathogenic to Panax quinquefolius was made. There were no significant differences in the average lesion size on detached roots between [...] Read more.
A comparison of the virulence, saprophytic growth, and genomes of 12 isolates of Ilyonectria mors-panacis and 4 isolates of I. robusta from Canada pathogenic to Panax quinquefolius was made. There were no significant differences in the average lesion size on detached roots between isolates of the two Ilyonectria species or isolates that originated from infected roots in first- or second-crop ginseng soils. This did not support the hypotheses that I. mors-panacis is always more virulent than I. robusta or that there is selection for higher virulence during the first crop. However, the average growth rate on potato dextrose agar for I. robusta was significantly greater than that of I. mors-panacis, and the average total genome size of I. robusta isolates was significantly smaller with a significantly higher GC content. On dendrograms based on nucleotide sequences of all predicted exons of the genomes, I. robusta isolates were distinguishable from I. mors-panacis isolates, which were similar but could be separated into types 1 and 2. The difference between type 1 and type 2 I. mors-panacis was not related to geographical origin, virulence, growth rate, or mating type. However, the division was also observed for the total predicted secretome, most notably small secreted cysteine-rich proteins and secreted proteases, indicating that type 1 and 2 isolates of I. mors-panacis may interact differently with their environment. Full article
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33 pages, 3031 KiB  
Review
Phytopathogenic Pseudomonas syringae as a Threat to Agriculture: Perspectives of a Promising Biological Control Using Bacteriophages and Microorganisms
by Pamela Córdova, Juan Pablo Rivera-González, Victoria Rojas-Martínez, Nicola Fiore, Roberto Bastías, Alan Zamorano, Francisca Vera, Jaime Barrueto, Belén Díaz, Carolina Ilabaca-Díaz, Assunta Bertaccini and Gastón Higuera
Horticulturae 2023, 9(6), 712; https://doi.org/10.3390/horticulturae9060712 - 16 Jun 2023
Cited by 3 | Viewed by 3755
Abstract
Pseudomonas syringae is a Gram-negative bacterium that infects a wide range of plants, causing significant economic losses in agricultural production. The pathogen exhibits a high degree of genetic and phenotypic diversity, which has led to the classification of P. syringae strains into different [...] Read more.
Pseudomonas syringae is a Gram-negative bacterium that infects a wide range of plants, causing significant economic losses in agricultural production. The pathogen exhibits a high degree of genetic and phenotypic diversity, which has led to the classification of P. syringae strains into different pathovars based on their host range and disease symptoms. Copper-based products have traditionally been used to manage infections in agriculture, but the emergence of copper-resistant strains has become a significant concern. Biological control is a promising strategy to manage P. syringae, as it offers an environmentally friendly and sustainable approach to disease management. The review includes an overview of the biology and epidemiology of P. syringae, and of the mechanisms of action of various biological control agents, mainly microorganisms (antagonistic bacteria, and fungi) and bacteriophages. Specifically, this review highlights the renewed interest in bacteriophages (bacteria-infecting viruses) due to their advantages over other eco-friendly management methods, thanks to their bactericidal properties and potential to target specific pathogenic bacteria. The potential benefits and limitations of biological control are also examined, along with research directions to optimize the use of this approach for the management of P. syringae. Full article
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17 pages, 1975 KiB  
Article
Improvement in Physiobiochemical and Yield Characteristics of Pea Plants with Nano Silica and Melatonin under Salinity Stress Conditions
by Wasimah B. Al-Shammari, Haya R. Altamimi and Khaled Abdelaal
Horticulturae 2023, 9(6), 711; https://doi.org/10.3390/horticulturae9060711 - 16 Jun 2023
Cited by 7 | Viewed by 1145
Abstract
The effect of nano silica (50 mL L−1) and melatonin (75 µM) individually or in combination in foliar applications on the morphophysiological, biochemical and yield properties of pea plants under salinity stress conditions was evaluated. Salt stress caused a remarkable decrease [...] Read more.
The effect of nano silica (50 mL L−1) and melatonin (75 µM) individually or in combination in foliar applications on the morphophysiological, biochemical and yield properties of pea plants under salinity stress conditions was evaluated. Salt stress caused a remarkable decrease in the growth and yield characteristics; for example, the plant dry weight, plant height, number of flowers plant−1, number of pods plant−1, weight of 100 green seeds and protein concentration in the pea plants during both seasons were decreased compared with the control. Similarly, their physiobiochemical characteristics were negatively affected; chlorophyll a, chlorophyll b and the relative water content (RWC) were significantly reduced in the stressed pea plants. However, malondialdehyde (MDA), hydrogen peroxide, the electrolyte leakage (EL%), super oxide and the antioxidant components (catalase (CAT), superoxide dismutase (SOD), peroxidase (POX) and total phenolic compounds) were significantly increased when the plants were under salt stress compared with the control plants. On the other hand, the foliar application of nano silica and melatonin individually or in combination enhanced the physiobiochemical characteristics, morphological characteristics and yield of the stressed pea plants. The best treatment was the combination treatment (nano silica + melatonin), which caused significant increases in the plant dry weight, plant height, number of flowers and pods plant−1, weight of 100 green seeds, protein concentration, chlorophyll concentrations and RWC in the stressed pea plants. Additionally, the combination treatment significantly decreased the EL%, MDA, O2⋅− and H2O2 and adjusted the upregulation of the antioxidant enzymes, proline and total phenolic compounds in the stressed plants compared with the stressed untreated pea plants. Generally, it can be suggested that the co-application of nano silica (50 mL L−1) + melatonin (75 µM) plays a positive role in alleviating the adverse impacts of salinity on pea plants by modifying the plant metabolism and regulating the antioxidant defense system as well as scavenging reactive oxygen species. Full article
(This article belongs to the Special Issue Research Advances in Horticultural Crop Physiology and Stress)
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13 pages, 1924 KiB  
Article
Fungicidal Effect of Guava Wood Vinegar against Colletotrichum coccodes Causing Black Dot Disease of Potatoes
by Mansour M. El-Fawy, Kamal A. M. Abo-Elyousr, Nashwa M. A. Sallam, Rafeek M. I. El-Sharkawy and Yasser Eid Ibrahim
Horticulturae 2023, 9(6), 710; https://doi.org/10.3390/horticulturae9060710 - 16 Jun 2023
Cited by 1 | Viewed by 1553
Abstract
Wood vinegar (WV) by-product of charcoal production is considered one of the most promising alternatives to synthetic pesticide and fertilizer applications, especially for organic production. Our goal in this study is to evaluate the efficacy of guava (Psidium guajava) WV to [...] Read more.
Wood vinegar (WV) by-product of charcoal production is considered one of the most promising alternatives to synthetic pesticide and fertilizer applications, especially for organic production. Our goal in this study is to evaluate the efficacy of guava (Psidium guajava) WV to control Colletotrichum coccodes, which causes black dot disease, and how it influences potato plant development and yield. This study tested the efficacy of guava WV against the pathogen both in vitro and under greenhouse conditions. Different guava WV concentrations were tested on pathogen growth development, including 0, 0.25%, 0.50%, 1%, 2%, and 3% (v/v). Data revealed that the pathogen’s mycelial growth was significantly inhibited at all the concentrations, and the highest inhibition (100%) was obtained at 3% guava WV. In greenhouse trials conducted for two seasons (2021 and 2022), guava WV applied as a foliar spray at the concentration of 2% and 3% considerably reduced the potato black dot severity evaluated as stem colonization (average of 22.9% for 2021, average of 22.5% for 2022), root covering with sclerotia (average of 21.7% for 2021, average of 18.3% for 2022) and wilted plants percentage (average of 27.8% for 2021, average of 33.3% for 2022). Overall, guava WV also showed a positive effect on plant growth by increasing plant height, stem diameter, and tuber yield per plant of treated potato in both seasons. Gas chromatography-mass spectrometry (GC-MS) analyses revealed the presence in guava WV of phenols, esters, organic acids, antioxidants, and alcohols. In conclusion, guava WV could represent a viable alternative for potato black dot disease management and for plant growth promotion. Full article
(This article belongs to the Special Issue Sustainable Control Strategies of Plant Pathogens in Horticulture)
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20 pages, 12542 KiB  
Communication
Leaf Area Estimation by Photographing Leaves Sandwiched between Transparent Clear File Folder Sheets
by Kohei Koyama
Horticulturae 2023, 9(6), 709; https://doi.org/10.3390/horticulturae9060709 - 16 Jun 2023
Viewed by 1546
Abstract
Image analysis is a promising method for in situ leaf area measurement. However, as leaves are three-dimensional, the use of two-dimensional images captured using a digital camera can result in underestimation. To overcome this problem, we tested a clear folder method. Before photographing [...] Read more.
Image analysis is a promising method for in situ leaf area measurement. However, as leaves are three-dimensional, the use of two-dimensional images captured using a digital camera can result in underestimation. To overcome this problem, we tested a clear folder method. Before photographing leaves with a digital camera, we flattened the leaves by sandwiching them between a pair of transparent plastic clear file folder sheets, which are stationery implements for carrying documents. Although similar methods have been previously proposed, their applicability to species with different leaf shapes has never been investigated. We tested the efficacy of this method using 12 species from various taxa (monocots, magnoliids, and basal and core eudicots) and leaf morphology (entire vs. lobed, simple vs. compound leaves, small and large leaves). Individual leaf areas and the Montgomery parameters obtained using this method were then compared with those obtained using the standard method, which employs a flatbed digital scanner. We observed strong correlations (R2 > 0.98) between the camera and scanner data. The regression slopes were close to unity (0.96–1.01) and the intercepts were close to zero. These findings suggest that the clear folder method can be used as an inexpensive alternative method to estimate the area of leaves in situ with acceptable accuracy. An introductory manual for readers unfamiliar with image analysis using ImageJ is presented in the end of the paper. Full article
(This article belongs to the Section Plant Nutrition)
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25 pages, 8109 KiB  
Article
Genome-Wide Identification, Characterization, and Expression Pattern of MYB Gene Family in Melastoma candidum
by Hui Li, Xiaoxia Wen, Mingke Wei, Xiong Huang, Seping Dai, Lin Ruan and Yixun Yu
Horticulturae 2023, 9(6), 708; https://doi.org/10.3390/horticulturae9060708 - 16 Jun 2023
Cited by 3 | Viewed by 1283
Abstract
The MYB gene family is significant in plants, playing a role in numerous plant development processes, including metabolism, hormone signal transduction, cell identity, and biotic and abiotic stresses. Due to the recent availability of the Melastoma candidum genome, this is the first time [...] Read more.
The MYB gene family is significant in plants, playing a role in numerous plant development processes, including metabolism, hormone signal transduction, cell identity, and biotic and abiotic stresses. Due to the recent availability of the Melastoma candidum genome, this is the first time that the MYB gene family has been identified in this species. This study identified 421 MYB gene members in the M. candidum genome using the HMMER search and BLASTp method. These MYBs were further divided into 10 sub-types, including R2R3, R-R, CPC-like, CCA1-like, TBP-like, R1R2R3, I-box, atypical MYB, MYB-CC, and MYB-like. Domain and conservation analyses revealed that each type of MYB was characterized by a different number and combination of SANTs/myb DNA-binding domains. Collinearity analysis revealed several gene duplication events within the MYB gene family. The Ka to Ks ratio suggested that most of the MYB genes underwent purifying selection during the evolution process. Phylogenetic analysis among three species confirmed our findings and displayed the evolutionary relationship of MYB genes in different species. RNA-seq of three developmental stages of flowers and WGCNA analysis identified McMYB113h, McMYB21b, and McGLK1c as playing a pivotal role during flower development in M. candidum. Finally, we conducted qRT-PCR experiments for 20 flower-development-related MYBs across 9 tissues to illustrate their expression patterns in M. candidum. This study establishes a foundation for exploring MYB gene resources and their potential applications in related industries of M. candidum. Full article
(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)
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19 pages, 1285 KiB  
Article
Integration of Chitosan and Biopesticides to Suppress Pre-Harvest Diseases of Apple
by Liza DeGenring, Kari Peter and Anissa Poleatewich
Horticulturae 2023, 9(6), 707; https://doi.org/10.3390/horticulturae9060707 - 16 Jun 2023
Viewed by 1818
Abstract
The natural product chitosan has been shown to reduce plant disease severity and enhance the efficacy of microbial biocontrol agents in several crops. However, little is known about the potential synergisms between chitosan and biopesticides and best use practices in apple production. The [...] Read more.
The natural product chitosan has been shown to reduce plant disease severity and enhance the efficacy of microbial biocontrol agents in several crops. However, little is known about the potential synergisms between chitosan and biopesticides and best use practices in apple production. The objectives of this study were to evaluate the effect of pre-harvest applications of chitosan alone and in combination with a commercial biopesticide to suppress fungal diseases of apple and to investigate the potential for chitosan to reduce the quantity of overwintering Venturia inaequalis spores in orchard leaf litter. Chitosan products, Tidal Grow and ARMOUR-Zen 15, and a commercial biopesticide, Serenade ASO, were tested in a research orchard in Pennsylvania and commercial orchards in New Hampshire. Chitosan applications reduced apple scab incidence and severity by up to 55% on fruit compared to the water control. Chitosan also reduced sooty blotch, flyspeck, and rust incidence on fruit. Furthermore, a chitosan + biopesticide treatment overlayed onto a grower standard spray program reduced diseases more effectively than the grower standard alone. However, this efficacy was dependent on the cultivar and pathogen. Chitosan did not reduce overwintering V. inaequalis ascospores. This research provides evidence that pre-harvest chitosan applications have the potential for disease management in apple production. Full article
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20 pages, 3823 KiB  
Article
A Simple Method for Drip Irrigation Scheduling of Spinach (Spinacia oleracea L.) in a Plastic Greenhouse in the North China Plain Using a 20 Cm Standard Pan Outside the Greenhouse
by Junfang Niu, Junxia Feng, Shengyao Liu, Songnan Jia and Fengcui Fan
Horticulturae 2023, 9(6), 706; https://doi.org/10.3390/horticulturae9060706 - 16 Jun 2023
Cited by 1 | Viewed by 1570
Abstract
The objective of this paper is to perform drip irrigation scheduling for spinach (Spinacia oleracea L.) in a plastic greenhouse using the standard 20 cm evaporation pan. A drip irrigation experiment with four levels of irrigation, i.e., 0.6, 0.8, 1.0, and 1.2 [...] Read more.
The objective of this paper is to perform drip irrigation scheduling for spinach (Spinacia oleracea L.) in a plastic greenhouse using the standard 20 cm evaporation pan. A drip irrigation experiment with four levels of irrigation, i.e., 0.6, 0.8, 1.0, and 1.2 times the cumulative evaporation of a 20 cm standard pan (Epan) were set up. The irrigation interval was controlled using a 20 mm Epan, and optimal irrigation water amounts of 0.8 Epan and 0.6 Epan were recommended for the spring and autumn growing seasons, respectively. Overirrigation (1.2 Epan) also led to yield losses, particularly for stem growth. In addition, a proper greenhouse index, defined as the ratio of the cumulative Epan inside and outside the greenhouse, could predict the Epan inside the greenhouse using the external Epan to a high degree of accuracy (daily data with r2 = 0.85, root mean square error (RMSE = 0.68 mm d−1), for a 4-day interval with r2 = 0.95, RMSE = 1.81 mm 4 day−1, and for the entire growth period with r2 = 1.0, RMSE = 2.40 mm). A simple and low-cost greenhouse index method could be used to formulate drip irrigation schedules for spinach in low-technology plastic greenhouses using a 20 cm standard pan outside the greenhouse. Full article
(This article belongs to the Section Vegetable Production Systems)
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11 pages, 1422 KiB  
Article
Bioefficacy of Lecanoric Acid Produced by Parmotrema austrosinense (Zahlbr.) Hale against Tea Fungal Pathogens
by Kalidoss Rajendran, Ponnusamy Ponmurugan, Balasubramanian Mythili Gnanamangai, Ponmurugan Karuppiah, Mohammed Rafi Shaik, Mujeeb Khan, Merajuddin Khan and Baji Shaik
Horticulturae 2023, 9(6), 705; https://doi.org/10.3390/horticulturae9060705 - 16 Jun 2023
Cited by 2 | Viewed by 1167
Abstract
Lichens are symbiotic organisms that are composed of fungal partners and photosynthetic algal partners. During the symbiotic process in lichen thallus, the fungus synthesizes certain secondary metabolites in which lecanoric acid is very important in terms of antibiotic properties. Considering the vital importance [...] Read more.
Lichens are symbiotic organisms that are composed of fungal partners and photosynthetic algal partners. During the symbiotic process in lichen thallus, the fungus synthesizes certain secondary metabolites in which lecanoric acid is very important in terms of antibiotic properties. Considering the vital importance of lecanoric acid, the present study aimed to produce lecanoric acid from the thallus of Parmotrema austrosinense lichen using Modified Bold’s basal salt medium and evaluate the bio-efficacy against tea fungal pathogens. Lecanoric acid was purified and confirmed by micro-crystallization method and subsequently bioassayed against tea fungal pathogens. The results revealed that lecanoric acid registered a significant antifungal activity in terms of the growth inhibition of test pathogens. Companion systemic and botanical fungicides were found to be inferior to lecanoric acid in the percentage of growth inhibition. The inhibition rate varied among tea pathogens. Of the tea pathogens tested, tea leaf disease-causing pathogens including Cercospora theae (C. theae), Glomerella cingulata (G. cingulate), and Phomopsis theae (P. theae) showed the highest percentage of growth inhibition followed by stem and root rot diseases. The present study suggests that lecanoric acid showed an inhibitory effect against tea pathogens, which might be due to antibiotic properties and fungicidal action of lecanoric acid. Full article
(This article belongs to the Special Issue Mycorrhizal Roles in Horticultural Plants)
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12 pages, 273 KiB  
Article
Effects of Magnetic Field and Ultrasound Applications on Endogenous Melatonin Content and Drought Stress Tolerance of Pepper Seedlings
by Gökçen Yakupoğlu
Horticulturae 2023, 9(6), 704; https://doi.org/10.3390/horticulturae9060704 - 16 Jun 2023
Viewed by 815
Abstract
Uncertainty about climate change exposes agriculture to high risks. Magnetic field (MF) applications are one of the methods that can be used to reduce the effects of environmental stress conditions. Melatonin (MEL) acts as a broad-spectrum antioxidant in eliminating the effects of damage [...] Read more.
Uncertainty about climate change exposes agriculture to high risks. Magnetic field (MF) applications are one of the methods that can be used to reduce the effects of environmental stress conditions. Melatonin (MEL) acts as a broad-spectrum antioxidant in eliminating the effects of damage caused in plants exposed to stress. This study aims to examine the effect of MF and ultrasound (US) applications on endogenous MEL levels in peppers and investigate the usability of treated seeds against drought stress. Pre-sowing pepper seeds, 0, 0.3, 0.9, 1.1 T MF and 0, 15, 30 min 40 Hz US were applied. The results show that the highest increase in MEL content was detected at 0.3 T MF with 82% and with 30 min of US application at 98%. MF and US treatments decreased the malondialdehyde (MDA) (19% and 35%, respectively) and hydrogen peroxide (H2O2) (52% and 58%, respectively) contents in seedlings. An increase of 24% and 22% (MF-US, respectively) was observed in catalase (CAT) enzyme activity with these applications. As a result, it was observed that MF and US treatments increased the endogenous MEL content and provided tolerance against drought stress. MF and US applications could be suggested as methods to increase drought tolerance in peppers by increasing the endogenous MEL content. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
11 pages, 3549 KiB  
Article
Vibration Analysis of Pulse-Width-Modulated Nozzles in Vineyard Blast Sprayers
by Coral Ortiz, Antonio Torregrosa, Verónica Saiz-Rubio and Francisco Rovira-Más
Horticulturae 2023, 9(6), 703; https://doi.org/10.3390/horticulturae9060703 - 16 Jun 2023
Cited by 1 | Viewed by 930
Abstract
Spraying systems to protect crops against pests are still necessary to maintain food production at the rates demanded by the current population. However, today, it is crucial to use precision agriculture to reduce the negative effects of pesticides and other agrochemicals such as [...] Read more.
Spraying systems to protect crops against pests are still necessary to maintain food production at the rates demanded by the current population. However, today, it is crucial to use precision agriculture to reduce the negative effects of pesticides and other agrochemicals such as fungicides. In particular, pressure fluctuations related to transient states when using pulse-width-modulated nozzles (PMW) have been reported to decrease the accuracy of preset flow rates in air-assisted orchard sprayers. The objective of this paper is to analyze the vibrations induced in the spraying system of a vineyard blast sprayer controlled by pulse-width-modulated nozzles, considering the instantaneous duty cycle (DC) as the control variable. An air-assisted vineyard sprayer was modified to host 24 solenoid shutoff valves with hollow disc–cone nozzles. A triaxial accelerometer was mounted to track the effect of duty cycle (20%, 30%, 50%, and 70%). In addition to accelerations, high-speed images were recorded, and the pressure according to time and the flow were estimated. The hydraulic system of the sprayer, when controlled in real time by the PWM solenoids, created pulsating impacts at the nozzle level with the same frequency of 10 Hz of the PMW system. The impact effect was significantly higher for low duty cycles under 40% DC. In addition, to demonstrate the inaccuracy of opening and closing the valves at a precisely specified time, this study also confirmed the divergence between the theoretical duty cycles commanded by the sprayer’s control unit and the actual ones measured in real time. The results of the analysis showed the difficulty of opening and closing the valves with precision to obtain accurate duty cycles in the practical implementation of smart sprayers and the importance of understanding the vibration effects of pulses in arrangements of multiple PWM nozzles working simultaneously. Full article
(This article belongs to the Section Viticulture)
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19 pages, 8029 KiB  
Article
Detection by Sensitive Real-Time Reverse Transcription Loop-Mediated Isothermal Amplification of Olive Leaf Yellowing Associated Virus and Its Incidence in Italy and Spain
by Andrea Giovanni Caruso, Sofia Bertacca, Arianna Ragona, Graziella Agrò, Maria Isabel Font-San-Ambrosio, Ana Alfaro-Fernández, Rocío Estévez Sánchez, Stefano Panno and Salvatore Davino
Horticulturae 2023, 9(6), 702; https://doi.org/10.3390/horticulturae9060702 - 15 Jun 2023
Cited by 2 | Viewed by 1339
Abstract
Olive trees (Olea europea L.) are constantly threatened by many viruses, such as the olive leaf yellowing-associated virus (OLYaV), that belong to the Olivavirus genus, family Closteroviridae. In this work, the OLYaV incidence in different regions of Italy and Spain, which [...] Read more.
Olive trees (Olea europea L.) are constantly threatened by many viruses, such as the olive leaf yellowing-associated virus (OLYaV), that belong to the Olivavirus genus, family Closteroviridae. In this work, the OLYaV incidence in different regions of Italy and Spain, which represent the two most important European areas for olive production, was evaluated through the development of a real-time reverse transcription-loop-mediated isothermal amplification (RT-LAMP) for reliable and sensitive OLYaV detection. The specificity and accuracy of the developed real-time RT-LAMP assay were determined; the assay showed that potential cross-reactivity with other viruses belonging to the Closteroviridae family was excluded. The LAMP assay detected OLYaV with a higher sensitivity than conventional end-point RT-PCR, detecting a total of 1.34 × 10−2 genome copies. A total of 80 and 120 plants of different olive cultivars from Spain (Comunitat Valenciana, Andalusia) and Italy (Sicily, Calabria, Apulia, Lazio, and Umbria) regions were tested, respectively. The percentage of infected plants was 46.25% and 30% for Spain and Italy, respectively, while the most susceptible cultivars were “Serrana Espadán” and “Villalonga” from Comunitat Valenciana and Andalusia regions (Spain) and “Ogliarola barese” from Apulia region (Italy). In addition, the survey demonstrated that the real-time RT-LAMP showed good sensitivity for OLYaV-positive sample detection, especially on asymptomatic olive trees. For this reason, the developed assay could be very suitable for phytopathological laboratories as a reliable and efficient method for a rapid and sensitive routine test on olive samples. Full article
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20 pages, 1128 KiB  
Article
Effect of Organic Fertilizer on the Growth and Physiological Parameters of a Traditional Medicinal Plant under Salinity Stress Conditions
by Abdollah Beyk-Khormizi, Mohammad Reza Sarafraz-Ardakani, Siavash Hosseini Sarghein, Seyed Mohammad Moshtaghioun, Seyed Mousa Mousavi-Kouhi and Mohammad Ehsan Taghavizadeh Yazdi
Horticulturae 2023, 9(6), 701; https://doi.org/10.3390/horticulturae9060701 - 15 Jun 2023
Cited by 2 | Viewed by 2331
Abstract
Foeniculum vulgare (fennel) is a medicinal and aromatic plant species from Apiaceae (Umbelliferae) and has been extensively used to treat digestive and pulmonary diseases. This plant is relatively sensitive to salinity. To investigate the effect of salinity stress at levels of 0, 40, [...] Read more.
Foeniculum vulgare (fennel) is a medicinal and aromatic plant species from Apiaceae (Umbelliferae) and has been extensively used to treat digestive and pulmonary diseases. This plant is relatively sensitive to salinity. To investigate the effect of salinity stress at levels of 0, 40, and 80 mM NaCl in combination with 0 and 5% v/v vermicompost mixed with soil on the growth as well as the physiological and biochemical traits of two fennel landraces planted in Urmia and Shiraz areas, a factorial experiment was conducted as a randomized complete block design in three replications under greenhouse conditions. The plants were sampled in the flowering stage eleven weeks after cultivation. As the results showed, vermicompost treatment together with salinity stress could enhance the growth traits of the plants, such as the length and dry weight of shoots; leaf area and dry weight of roots; photosynthetic pigments, i.e., chlorophylls and carotenoids; membrane stability index; relative water content, soluble sugar, soluble protein, proline, total phenol, and anthocyanin in the shoots; mineral elements, i.e., phosphate, nitrate, zinc, molybdenum, magnesium, and iron in the shoots; and potassium and calcium in the shoots and roots. The interaction of vermicompost and salinity also decreased the aldehydes, total flavonoids, activity of catalase enzyme and shoot starch, soluble sugar and root proline, and sodium content of both shoots and roots. In a comparison of the two studied fennel landraces, the Shiraz landrace emerged to be less affected by salinity stress. In saline conditions, vermicompost caused a change in the physiological and biochemical parameters of both fennel landraces and improved their growth. The improvement in the growth conditions in the Urmia landrace was more obvious due to the use of vermicompost. Using vermicompost plus 40 mM NaCl salinity, the dry weight of the shoot and leaf surface of the Urmia landrace increased by about 3 and 2.5 times, respectively, and under 80 mM NaCl, the dry weight of the shoot and leaf surface increased by 2.7 and 1.2 times compared to the control. According to the experiments, it seems that vermicompost can limit the harmful effects of salinity on fennel plants by affecting photosynthetic pigments, osmolytes, phenolic compounds, antioxidants, the stability of membranes, and the availability of water and essential minerals. Full article
(This article belongs to the Special Issue Advances in Ecophysiology of Horticultural Crops)
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12 pages, 930 KiB  
Article
From Fresh to Dried Lavender Flower: Changes in Phytochemical Profile According to Drying Method
by Matteo Caser, Nicole Mélanie Falla, Sonia Demasi and Valentina Scariot
Horticulturae 2023, 9(6), 700; https://doi.org/10.3390/horticulturae9060700 - 14 Jun 2023
Cited by 3 | Viewed by 1550
Abstract
Lavandula angustifolia Mill. is a part of the Lamiaceae family, which includes aromatic plants used in perfumery, manufactory, food, ornamental, and medicinal sectors. Both fresh and dried lavender flowers can be exploited in different ways; however, post-harvest treatments such as drying processes can [...] Read more.
Lavandula angustifolia Mill. is a part of the Lamiaceae family, which includes aromatic plants used in perfumery, manufactory, food, ornamental, and medicinal sectors. Both fresh and dried lavender flowers can be exploited in different ways; however, post-harvest treatments such as drying processes can help maintain the flowers’ properties for a longer period. This study analyzed fresh (F) and dried lavender flower ultrasound-assisted extracts, comparing two different drying methods, i.e., heat-pump drying (HP) and hot-air drying (HA), to assess potential differences in their effect on the phytochemical composition (total phenolic content, total anthocyanin content, and phenolic profile) and antioxidant activity (FRAP, DPPH, and ABTS assays) of flowers, focusing on three lavender selections from north-western Alps (i.e., Susa, Stura, and Tanaro). Results showed that HP-dried flowers are to be preferred over HA-dried flowers, as they contain +66.73% of phenolics and +62.2% of anthocyanins, and they have higher antioxidant activity (from 60.32% to 284.3% more according to the assay). HP-dried flowers, particularly those from the Tanaro selection, showed also higher values in the relative antioxidant capacity index (RACI) and the global antioxidant score (GAS), ranking together with the fresh flowers. Nine bioactive compounds out of thirteen were detected by means of HPLC, seven in F (caffeic acid, hyperoside, quercetin, ellagic acid, catechin, epicatechin, and dehydroascorbic acid), four in HA (ferulic acid, hyperoside, quercitrin, and epicatechin), and two in HP (caffeic acid and hyperoside). The higher temperatures used in HA probably promoted oxidative and biochemical reactions that led to the presence and increase in these compounds. However, many other phenolic compounds may contribute to the antioxidant power of lavender extracts. Overall, HP resulted in an effective and sustainable method for drying lavender flowers and may have interesting applications to obtain final products richer in bioactive compounds and antioxidant activity to be used in the functional food industry. Full article
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17 pages, 6066 KiB  
Article
RVE1, DBB1b, and COL2 Transcription Factors Are Responsive to Combined Stress by UV-B Radiation and Cold in Bell Pepper (Capsicum annuum)
by Brandon Estefano Morales-Merida, Jesús Christian Grimaldi-Olivas, Abraham Cruz-Mendívil, Claudia Villicaña, José Benigno Valdez-Torres, José Basilio Heredia, Rubén León-Chan, Luis Alberto Lightbourn-Rojas and Josefina León-Félix
Horticulturae 2023, 9(6), 699; https://doi.org/10.3390/horticulturae9060699 - 14 Jun 2023
Viewed by 1184
Abstract
Ultraviolet-B radiation (UV-B) and cold limit the growth and development of plants, which generates changes in gene expression. This allows plants to respond to stress through regulatory proteins, such as transcription factors, that activate or repress the expression of stress-response genes. RNA-Seq data [...] Read more.
Ultraviolet-B radiation (UV-B) and cold limit the growth and development of plants, which generates changes in gene expression. This allows plants to respond to stress through regulatory proteins, such as transcription factors, that activate or repress the expression of stress-response genes. RNA-Seq data and WGCNA analyses were utilized to identify the hub genes. Our study found a total of 25, 24, and 29 transcription factors at different time points T1, T2, and T3, respectively, under combined stress (ultraviolet-B radiation and cold). RVE1 (MYB-related), COL2 (CO-like), and DBB1b (DBB) were identified as candidate hub genes. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that RVE1, DBB1b, and COL2 were mostly involved in energy production, the antioxidant system (enzymatic and non-enzymatic), signaling through abscisic acid and CA2+, response to light stimulus, and cellular homeostasis. These findings provide the basis for further investigation related to UV-B radiation and cold stress response mechanisms in plants. Full article
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17 pages, 3619 KiB  
Article
Genome-Wide Identification of the RsSWEET Gene Family and Functional Analysis of RsSWEET17 in Root Growth and Development in Radish
by Xiaoli Zhang, Yang Cao, Ruixian Xin, Liang Xu, Yan Wang, Lun Wang, Yinbo Ma and Liwang Liu
Horticulturae 2023, 9(6), 698; https://doi.org/10.3390/horticulturae9060698 - 14 Jun 2023
Cited by 1 | Viewed by 949
Abstract
SWEET (Sugars Will Eventually be Exported Transporter) genes play essential roles in various biological processes, including phloem loading, sugar efflux, plant development and stress response. In this study, a total of 33 RsSWEET gene members were identified in the radish genome. [...] Read more.
SWEET (Sugars Will Eventually be Exported Transporter) genes play essential roles in various biological processes, including phloem loading, sugar efflux, plant development and stress response. In this study, a total of 33 RsSWEET gene members were identified in the radish genome. They could be divided into four subfamilies and are distributed on eight radish chromosomes. Cis-acting regulatory element analysis indicated that these RsSWEET genes were potentially involved in the radish growth and development and stress response process, including circadian control and light response and responses to numerous stresses, including low-temperature and drought stress. Transcriptome data analysis revealed that a number of RsSWEET genes exhibited specific expression patterns in different tissues and developmental stages of radish. Moreover, several RsSWEET genes (e.g., RsSWEET2a, RsSWEET3a, RsSWEET16b and RsSWEET17) showed differential expression profiles under various abiotic stresses, including cold, heat, salt, Cd and Pb stress. Remarkably, the RsSWEET17 was specifically expressed in the cambium of radish. RsSWEET17 was heterologously expressed in yeast strain EBY.VW4000, which suggested that it has the ability to transport sugar. Notably, RsSWEET17-overexpressing Arabidopsis plants exhibited excessive root length, greater fresh weight and higher soluble sugar content (SSC) accumulation compared with wild-type (WT) plants, indicating that RsSWEET17 might positively regulate radish taproot development by strategically manipulating sugar accumulation. Collectively, these results clarify the molecular mechanisms underlying RsSWEET-mediated sugar accumulation and root growth and development in radish. Full article
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