Editor's Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area.The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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Article
A Lignin-Rich Extract of Giant Reed (Arundo donax L.) as a Possible Tool to Manage Soilborne Pathogens in Horticulture: A Preliminary Study on a Model Pathosystem
Horticulturae 2022, 8(7), 589; https://doi.org/10.3390/horticulturae8070589 - 30 Jun 2022
Cited by 1 | Viewed by 362
Abstract
Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic [...] Read more.
Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic requirements. Some studies have already highlighted antimicrobial and antifungal properties of giant reed-derived compounds. This study aimed at investigating the potential of a lignin-rich giant reed extract for crop protection. The extract, obtained by dry biomass treatment with potassium hydroxide at 120 °C, followed by neutralization, was chemically characterized. A preliminary in vitro screening among several pathogenic strains of fungi and oomycetes showed a high sensitivity by most of the soilborne pathogens to the extract; thus, an experiment was performed with the model pathosystem, Pythium ultimum–zucchini in a growth substrate composed of peat or sand. The adsorption by peat and sand of most of the lignin-derived compounds contained in the extract was also observed. The extract proved to be effective in restoring the number of healthy zucchini plantlets in the substrate infected with P. ultimum compared to the untreated control. This study highlights the potential of the lignin-rich giant reed extract to sustain crop health in horticulture. Full article
(This article belongs to the Special Issue Sustainable Control Strategies of Plant Pathogens in Horticulture)
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Article
Characteristics of Meteorological Conditions during a Severe Outbreak of Onion Downy Mildew and Metalaxyl Sensitivity of Peronospora destructor in Saga, Japan, in 2016
Horticulturae 2022, 8(7), 578; https://doi.org/10.3390/horticulturae8070578 - 26 Jun 2022
Viewed by 530
Abstract
In 2016, an onion downy mildew epidemic caused by Peronospora destructor severely damaged the commercial onion fields in Saga Prefecture, western Japan. To identify the factors underlying the outbreak, we investigated the symptoms of downy mildew caused by secondary infections and examined P. [...] Read more.
In 2016, an onion downy mildew epidemic caused by Peronospora destructor severely damaged the commercial onion fields in Saga Prefecture, western Japan. To identify the factors underlying the outbreak, we investigated the symptoms of downy mildew caused by secondary infections and examined P. destructor’s sensitivity to metalaxyl, the most effective traditional fungicide used against this onion pathogen, in 2016–2018. Disease symptoms developed in late March 2016, which was earlier than symptom development in 2017 and 2018. Furthermore, there were synchronous repeated disease development and favourable meteorological conditions for infection in early and late April resulting in the development of polycyclic epidemics. In field trials from 2016 to 2018, the efficacy of chlorothalonil + metalaxyl-M application ranged 18–45%, as calculated by comparing disease severity at the final stage of each treatment to that in the untreated plots. On the basis of the metalaxyl sensitivity observed in 2016, the effective concentration, which reduced germ-tube elongation in P. destructor by 50%, exceeded 200 µg ai/mL for certain strains. Our observations indicate that these characteristic meteorological conditions were major factors contributing to the severe disease outbreak in 2016. The emergence of less-metalaxyl-sensitive P. destructor strains may be an additional predisposing factor. Full article
(This article belongs to the Special Issue Horticultural Plants Pathology and Advances in Disease Management)
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Article
Early-Summer Deficit Irrigation Increases the Dry-Matter Content and Enhances the Quality of Ambrosia™ Apples At- and Post-Harvest
Horticulturae 2022, 8(7), 571; https://doi.org/10.3390/horticulturae8070571 - 23 Jun 2022
Viewed by 395
Abstract
Ambrosia™ is an apple that naturally has limited post-harvest quality retention, which is accompanied by relatively low dry-matter content (DMC). This trial was proposed to improve the DMC of this apple by scheduling deficit irrigation (DI) conducted in a semi-arid orchard in the [...] Read more.
Ambrosia™ is an apple that naturally has limited post-harvest quality retention, which is accompanied by relatively low dry-matter content (DMC). This trial was proposed to improve the DMC of this apple by scheduling deficit irrigation (DI) conducted in a semi-arid orchard in the Similkameen Valley (British Columbia, Canada) in 2018 and 2019. Two irrigation regimes were implemented in the orchard: commercial irrigation (CI) and DI, which was defined as irrigation for 2/5 of the timespan of CI. Five irrigation treatments were conducted: 1—adequate irrigation (AI), which used CI for the whole season; 2—early-summer DI (ED), which used DI from 20 June to 20 July; 3—middle-summer DI (MD), which used DI from 20 July to 20 August; 4—late-summer DI (LD), which used DI from 20 August to 10 days before harvest; and 5—double-period DI (DD), which covered the interval of MD and LD. The DI treatments resulted in a significant decrease from AI −1.0 to −1.5 MPa in stem water potential (SWP), followed by subsequent recovery. Conversely, SWP did not recover, and instead reached a critical low of −2.5 MPa under continued deficit conditions (DD). This, in turn, correlated with significant differences in the DMC among the treatments. Specifically, ED resulted in a rapid and sustained increase in DMC throughout the summer. At the time of harvest, ED resulted in a five-fold increase in the proportion of fruit, with greater than 16% DMC and 15% DMC in 2018 and 2019, respectively, compared to AI. DD resulted in similar levels of DMC elevation compared to ED, but also caused irregular maturation and the increased incidence of soft scald disorder in the post-harvest period. MD and LD had variable effects on DMC, and also increased the incidence of soft scald disorder. Consequently, fruit collected from the ED resulted in the best blush color attributes, higher soluble solid content, and a significant improvement in the post-harvest retention of both fruit firmness and acidity. The ED irrigation model would be recommended as a practical way for Ambrosia™ growers in semi-arid regions to decrease water usage, and to ensure high fruit quality for superior marketing and sustainable production. Full article
(This article belongs to the Special Issue Irrigation and Water Management in Horticulture)
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Article
Evaluation of the Storage Performance of ‘Valencia’ Oranges and Generation of Shelf-Life Prediction Models
Horticulturae 2022, 8(7), 570; https://doi.org/10.3390/horticulturae8070570 - 22 Jun 2022
Viewed by 447
Abstract
We conducted a large-scale, high-throughput phenotyping analysis of the effects of various preharvest and postharvest features on the quality of ‘Valencia’ oranges in order to develop shelf-life prediction models. Altogether, we evaluated 10,800 oranges (~3.6 tons) harvested from three orchards at different periods [...] Read more.
We conducted a large-scale, high-throughput phenotyping analysis of the effects of various preharvest and postharvest features on the quality of ‘Valencia’ oranges in order to develop shelf-life prediction models. Altogether, we evaluated 10,800 oranges (~3.6 tons) harvested from three orchards at different periods and conducted 151,200 measurements of 14 quality parameters. The storage time was the most important feature affecting fruit quality, followed by the yield, storage temperature, humidity, and harvest time. The storage time and temperature features significantly affected (p < 0.001) all or most of the tested quality parameters, whereas the harvest time, yield, and humidity conditions significantly affected several particular quality parameters, and the selection of rootstocks had no significant effect at all. Five regression models were evaluated for their ability to predict fruit quality based on preharvest and postharvest features. Non-linear Support Vector Regression (SVR) combined with a data-balancing approach was found to be the most effective approach. It allowed the prediction of fruit-acceptance scores among the full data set, with a root mean square error (RMSE) of 0.195 and an R2 of 0.884. The obtained data and models should assist in determining the potential storage times of different batches of fruit. Full article
(This article belongs to the Special Issue Postharvest Management of Citrus Fruit)
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Article
Enhancement of Anti-Inflammatory and Antioxidant Activities of Mango Fruit by Pre- and Postharvest Application of Salicylic Acid
Horticulturae 2022, 8(6), 555; https://doi.org/10.3390/horticulturae8060555 - 20 Jun 2022
Viewed by 563
Abstract
Mango fruits have a high nutritional value and are beneficial to health. However, losses frequently occur after harvest, because they are perishable. Salicylic acid (SA) can be used to preserve fruit quality and maintain their nutritional contents. Therefore, this study was conducted to [...] Read more.
Mango fruits have a high nutritional value and are beneficial to health. However, losses frequently occur after harvest, because they are perishable. Salicylic acid (SA) can be used to preserve fruit quality and maintain their nutritional contents. Therefore, this study was conducted to investigate the effects of applications of 2 mM SA on the physicochemical properties, bioactive compounds, and antioxidant and anti-inflammatory activities of mango fruit. For this purpose, mango fruits received preharvest (Pre SA) or postharvest applications of SA (Post SA), or their combination (Pre + Post SA); the fruits were stored at 13 °C for 20 days. Weight loss, decay, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity were maintained in SA-treated fruit. The Pre + Post SA treatment was superior in delaying fruit ripening, and maintaining lower soluble solids contents and higher total acidity. In addition, total phenolic compounds, ferric reducing antioxidant power, and free radical scavenging activity of anti-inflammatory substances (such as nitric oxide), as well as hyaluronidase inhibition, were higher in the Pre + Post SA treatment throughout storage. Therefore, both pre- and postharvest SA treatments are recommended for preserving the quality of mango fruit, such as Nam Dok Mai Si Thong, and for maintaining their nutritional properties for human health. Full article
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Article
Antifungal Activity of Volatile Organic Compounds from Bacillus velezensis CE 100 against Colletotrichum gloeosporioides
Horticulturae 2022, 8(6), 557; https://doi.org/10.3390/horticulturae8060557 - 20 Jun 2022
Cited by 1 | Viewed by 533
Abstract
Colletotrichum gloeosporioides is the most prevalent phytopathogen, causing anthracnose disease that severely affects the production of various fruit trees, including walnut and jujube. In this study, the volatile organic compounds (VOCs) from Bacillus velezensis CE 100 disrupted the cell membrane integrity of C. [...] Read more.
Colletotrichum gloeosporioides is the most prevalent phytopathogen, causing anthracnose disease that severely affects the production of various fruit trees, including walnut and jujube. In this study, the volatile organic compounds (VOCs) from Bacillus velezensis CE 100 disrupted the cell membrane integrity of C. gloeosporioides and reduced the spore germination by 36.4% and mycelial growth by 20.0% at a bacterial broth concentration of 10%, while the control group showed no antifungal effect. Based on the headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) analysis, seven VOCs were identified from the headspace of B. velezensis CE 100. Out of the seven VOCs, 5-nonylamine and 3-methylbutanoic acid were only detected in the headspace of B. velezensis CE 100 but not in the control group. Both 5-nonylamine and 3-methylbutanoic acid showed significant antifungal activity against the spore germination and mycelial growth of C. gloeosporioides. Treatment with 100 µL/mL of 5-nonylamine and 3-methylbutanoic acid suppressed the spore germination of C. gloeosporioides by 10.9% and 30.4% and reduced mycelial growth by 14.0% and 22.6%, respectively. Therefore, 5-nonylamine and 3-methylbutanoic acid are the potential antifungal VOCs emitted by B. velezensis CE 100, and this is the first report about the antifungal activity of 5-nonylamine against C. gloeosporioides. Full article
(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)
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Article
Copper Stress Enhances the Lignification of Axial Organs in Zinnia elegans
Horticulturae 2022, 8(6), 558; https://doi.org/10.3390/horticulturae8060558 - 20 Jun 2022
Cited by 1 | Viewed by 672
Abstract
Zinnia elegans Jacq. is an ornamental plant, widely used in landscaping. Heavy-metal pollution in urban and rural areas is still increasing, which determines the actuality of studying plants’ reactions to pollutants. Zinnia was not sufficiently studied in this regard, so the aim of [...] Read more.
Zinnia elegans Jacq. is an ornamental plant, widely used in landscaping. Heavy-metal pollution in urban and rural areas is still increasing, which determines the actuality of studying plants’ reactions to pollutants. Zinnia was not sufficiently studied in this regard, so the aim of our research was to identify morphophysiological changes in this species under excess copper concentration in the soil. For this, we treated a growth substrate with 200 µM CuSO4 solution for 20 days. At the end of the treatment, several morphological, biochemical, and molecular genetic traits were evaluated: the root and the shoot size; the concentration of H2O2 and malondialdehyde (MDA), as indicators of stress; the amount of the phenolic compounds and lignin; and the level of the expression of genes, which encoded their biosynthesis. The Cu amount in the substrate and zinnia organs was quantified using atomic-absorption spectroscopy; hydrogen peroxide, MDA, and phenolic compounds were determined spectrophotometrically, while the amount of lignin was determined according to Klason. Real-time PCR was used for estimation of the gene-transcription level. Lignin in tissues was visualized by fluorescent microscopy. In experimental plants, Cu accumulation was higher in the root than in the stem. This caused an increase in stress markers and a decrease in the root and stem lengths. For the first time for zinnia, it was shown that for several genes—4-coumarate-CoA ligase (4CL), cinnamoyl alcohol dehydrogenase (CAD), and class III peroxidase (PRX)—the level of expression increased under copper treatment. The rise of the transcripts’ amount of these genes was accompanied by a thickening and lignification of the cell walls in the metaxylem vessels. Thus, the adaptation of zinnia to the excess Cu in the growth medium was associated with the metabolic changes in the phenylpropanoid pathway. As a result, the lignification increased in the root, which led to the accumulation of Cu in this organ and limited its translocation through the xylem to the stem, which provided plant growth. Full article
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Article
Effects of Cold Temperature and Acclimation on Cold Tolerance and Cannabinoid Profiles of Cannabis sativa L. (Hemp)
Horticulturae 2022, 8(6), 531; https://doi.org/10.3390/horticulturae8060531 - 15 Jun 2022
Viewed by 848
Abstract
Hemp (Cannabis sativa) is a multi-use crop garnering newfound attention from researchers and consumers. While interest has emerged, a lack of substantiated research still exists regarding effects of adverse weather events on physiological health and secondary metabolite production of hemp. The [...] Read more.
Hemp (Cannabis sativa) is a multi-use crop garnering newfound attention from researchers and consumers. While interest has emerged, a lack of substantiated research still exists regarding effects of adverse weather events on physiological health and secondary metabolite production of hemp. The aim of this experiment was to assess cold tolerance of hemp using the cultivars ‘FINOLA’ and ‘AutoCBD’. Effects of cultivar, plant age, cold acclimation, frequency of cold treatments, and intensity of cold treatments were all considered in regard to their influence on physiological stress, biomass, and cannabinoid profile. Few effects of sequential cold treatments were noted, and they were not moderated by cold acclimation, which tended to have negative effects across many responses. This detrimental effect of cold acclimation conditions was further observed in decreased total CBD % and total THC % compared to non-acclimated plants. These findings bear consideration when assessing the unpredictability of a changing climate’s effects on the heath and cannabinoid profile of hemp. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
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Article
Nitrogen Fertigation Rate and Foliar Urea Spray Affect Plant Growth, Nitrogen, and Carbohydrate Compositions of Encore Azalea ‘Chiffon’ Grown in Alternative Containers
Horticulturae 2022, 8(6), 525; https://doi.org/10.3390/horticulturae8060525 - 15 Jun 2022
Viewed by 419
Abstract
The objective of this study was to investigate the plant vegetative growth, flower production, nitrogen (N) concentration, and carbohydrate compositions of Encore® azalea ‘Chiffon’ when fertigated with five N rates—0, 5, 10, 15, and 20 mM N—and grown in two types of [...] Read more.
The objective of this study was to investigate the plant vegetative growth, flower production, nitrogen (N) concentration, and carbohydrate compositions of Encore® azalea ‘Chiffon’ when fertigated with five N rates—0, 5, 10, 15, and 20 mM N—and grown in two types of containers, a black plastic and a biodegradable container, during one growing season. Foliar urea of 3% was applied to half of the plants in late fall to investigate its effect on plant N and carbohydrate concentrations. The paper biocontainers resulted in superior plant growth, increased plant size, dry weights, root length and surface area compared with the plastic containers with N rates of 10, 15, and 20 mM. The paper biocontainers also increased N uptake and carbohydrate concentrations mainly by increasing plant biomass. High N rates of 10 to 20 mM combined with urea spray and biocontainers generally resulted in the highest plant N concentrations. Foliar urea application in late fall tended to increase plant N concentration but decreased carbohydrates, including starch, glucose, fructose, and sucrose, to varying degrees, likely due to increased N assimilation. Fall foliar urea spray can be effective in improving the N status of azalea plants without affecting plant biomass. Full article
(This article belongs to the Section Plant Nutrition)
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Article
Effect of Covering Crops between Rows on the Vineyard Microclimate, Berry Composition and Wine Sensory Attributes of ‘Cabernet Sauvignon’ (Vitis vinifera L. cv.) Grapes in a Semi-Arid Climate of Northwest China
Horticulturae 2022, 8(6), 518; https://doi.org/10.3390/horticulturae8060518 - 13 Jun 2022
Viewed by 563
Abstract
Covering crops was a commonly used viticultural technique to adjust the vineyard microclimate, thus affecting the grape and wine quality. In this two-year study, the purslane (Portulaca oleracea L.) was used to cover the lands between rows in the vineyards located in [...] Read more.
Covering crops was a commonly used viticultural technique to adjust the vineyard microclimate, thus affecting the grape and wine quality. In this two-year study, the purslane (Portulaca oleracea L.) was used to cover the lands between rows in the vineyards located in the semi-arid Northwest China, Xinjiang. Results showed that the photosynthetically active radiation around the fruit zone and the temperature with the purslane covering treatment decreased. Compared with the clean tillage, covering purslane had lower TSS and higher TA in the grape berries, while lower alcohol content and higher TA was also found in their corresponding wines. Covering purslane treatment significantly increased the contents of anthocyanin and flavonol in the grapes and wines in the year 2018, but no significant effect on flavanols was observed in the wines. Norisoprenoids, esters, and C6 alcohols in the grapes and wines were increased in the purslane covering treatment, respectively. Additionally, compared to the clean tillage, the purslane covering treatment significantly improved the sensory value of the wines, especially the floral aroma and the complexity of the wines. This study helped us to better understand the feasibility of applying covering purslane in viticulture in the semi-arid climate of Northwest China. Full article
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Article
Effect of Flavonoid Dynamic Changes on Flower Coloration of Tulipa gesneiana ‘Queen of Night’ during Flower Development
Horticulturae 2022, 8(6), 510; https://doi.org/10.3390/horticulturae8060510 - 09 Jun 2022
Viewed by 638
Abstract
Tulipa gesneriana has rich cultivars with abundant flower colors; among them, black tulips have become precious cultivars for their rareness in nature. It is of great significance to understand its color formation mechanism for breeding new cultivars with a blackish flower color in [...] Read more.
Tulipa gesneriana has rich cultivars with abundant flower colors; among them, black tulips have become precious cultivars for their rareness in nature. It is of great significance to understand its color formation mechanism for breeding new cultivars with a blackish flower color in the future. In this present study, petals at five developmental stages of Tulipa gesneriana ‘Queen of Night’ (shorted for ‘QN’), a typical black tulip cultivar, were collected to identity the flavonoid composition and compare the accumulation along with the flower development process, aiming to explore the metabolic mechanism of its flower coloration. By using UPLC-Q-TOF-MS, three anthocyanins and nineteen anthoxanthins (including eighteen flavonols and one flavone) were detected in the petals of ‘QN’. The anthocyanins were identified as delphinidin 3-o-rutinoside, cyanidin 3-o-rutinoside and pelargonidin 3-o-rutinoside, respectively. The main flavonols were identified as quercetin, kaempferol, isorhamnetin, naringin and their glycosides. The only one flavone substance was identified as an apigenin derivative. By comparing the content, anthocyanins were the most abundant substance in the petals of ‘QN’, and showed obvious regularity in the development process. With the flower opening, the anthocyanin content accumulated continuously, and reached the highest level at 3575.9 μg·g−1·FW at S5, accounting for 80% of the total flavonoids. Among them, delphinidin 3-o-rutinoside and cyanidin 3-o-rutinoside made the main contribution to the coloration of ‘QN’. The content of anthoxanthins increased first and then decreased, reaching the highest to 1114.8 μg·g−1·FW at S3. Quercetin and its glycosides were the most important flavonol substances in the petals of ‘QN’, accounting for more than 60% of the total anthoxanthins in the five stages. The content of a flavone identified was extremely low, suggesting a limited role in the flower color of ‘QN’. Taken together, the flower color presentation of ‘QN’ was closely related to the composition and accumulation of anthocyanins and flavonols; anthocyanins were the main substances that determine the petal coloration of ‘QN’, and the high content of flavonols played a role of co-pigmentation with these anthocyanins. Full article
(This article belongs to the Special Issue Advances in Ornamental Plant Cultivation and Physiology)
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Article
Gamma Radiation (60Co) Induces Mutation during In Vitro Multiplication of Vanilla (Vanilla planifolia Jacks. ex Andrews)
Horticulturae 2022, 8(6), 503; https://doi.org/10.3390/horticulturae8060503 - 05 Jun 2022
Viewed by 622
Abstract
In vitro mutagenesis is an alternative to induce genetic variation in vanilla (Vanilla planifolia Jacks. ex Andrews), which is characterized by low genetic diversity. The objective of this study was to induce somaclonal variation in V. planifolia by gamma radiation and detect [...] Read more.
In vitro mutagenesis is an alternative to induce genetic variation in vanilla (Vanilla planifolia Jacks. ex Andrews), which is characterized by low genetic diversity. The objective of this study was to induce somaclonal variation in V. planifolia by gamma radiation and detect it using inter-simple sequence repeat (ISSR) molecular markers. Shoots previously established in vitro were multiplied in Murashige and Skoog culture medium supplemented with 2 mg·L−1 BAP (6-benzylaminopurine). Explants were irradiated with different doses (0, 20, 40, 60, 80 and 100 Gy) of 60Co gamma rays. Survival percentage, number of shoots per explant, shoot length, number of leaves per shoot, and lethal dose (LD50) were recorded after 60 d of culture. For molecular analysis, ten shoots were used for each dose and the donor plant as a control. Eight ISSR primers were selected, and 43 fragments were obtained. The percentage of polymorphism (% P) was estimated. A dendrogram based on Jaccard’s coefficient and the neighbor joining clustering method was obtained. Results showed a hormetic effect on the explants, promoting development at low dose (20 Gy) and inhibition and death at high doses (60–100 Gy). The LD50 was observed at the 60 Gy. Primers UBC-808, UBC-836 and UBC-840 showed the highest % P, with 42.6%, 34.7% and 28.7%, respectively. Genetic distance analysis showed that treatments without irradiation and with irradiation presented somaclonal variation. The use of gamma rays during in vitro culture is an alternative to broaden genetic diversity for vanilla breeding. Full article
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Article
Evaluation of Fungicides and Application Strategies for the Management of the Red Leaf Blotch Disease of Almond
Horticulturae 2022, 8(6), 501; https://doi.org/10.3390/horticulturae8060501 - 04 Jun 2022
Viewed by 683
Abstract
Red leaf blotch (RLB) of almond, caused by Polystigma amygdalinum, is an important foliar disease of this nut tree in the Mediterranean basin and especially in Spain. In recent years, the control of this disease has become a key factor in the [...] Read more.
Red leaf blotch (RLB) of almond, caused by Polystigma amygdalinum, is an important foliar disease of this nut tree in the Mediterranean basin and especially in Spain. In recent years, the control of this disease has become a key factor in the management of Spanish almond orchards. The management of RLB is not easy due to intrinsic factors of the disease (e.g., long infection and latency periods) and the low number of registered fungicides in this country. From 2015 to 2019, different field trials were conducted in the Lleida region, NE Spain, to evaluate the efficacy of several fungicide products and of application strategies to control this disease. Systemic fungicides, which included fluopyram, trifloxystrobin, and mixtures of fluopyram + trifloxystrobin and pyraclostrobin + boscalid, performed better than contact and penetrant products and showed up to 90% control against RLB. However, the efficacy of the tested fungicides varied depending on the year. In terms of application strategies, when fungicide applications were conducted following specific meteorological conditions (after 15 days from >15 mm rainfalls with ≈10–15 °C as the minimum average temperature), their efficacy was comparable to that of calendar-based treatments (every 14, 21, or 31 days from petal fall) but with fewer applications (depending on the year, 2–4 applications as compared with 5–9 for calendar treatments). Full article
(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)
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Article
Combined Nano Silver, α-Aminoisobutyric Acid, and 1-Methylcyclopropene Treatment Delays the Senescence of Cut Roses with Different Ethylene Sensitivities
Horticulturae 2022, 8(6), 482; https://doi.org/10.3390/horticulturae8060482 - 28 May 2022
Viewed by 535
Abstract
Flower senescence varies among cut roses (Rosa hybrida L.), and it is known that the postharvest life of ethylene-sensitive flowers is strongly related to the transcriptional accumulation of ethylene biosynthesis genes, whereas that of ethylene-insensitive flowers is shortened by water stress. These [...] Read more.
Flower senescence varies among cut roses (Rosa hybrida L.), and it is known that the postharvest life of ethylene-sensitive flowers is strongly related to the transcriptional accumulation of ethylene biosynthesis genes, whereas that of ethylene-insensitive flowers is shortened by water stress. These different responses of flowers to hormone and water stresses limit the action of preservatives in inhibiting the postharvest deterioration of cut rose flowers. This study was conducted to investigate the effects of the combined application of antibacterial agents and ethylene biosynthesis and binding inhibitors on the postharvest life and quality of the cut rose cultivars ‘Matador’ (ethylene-sensitive) and ‘Dolcetto’ (ethylene-insensitive). Cut flowers were treated with nano silver (NS), a combination of NS and α-aminoisobutyric acid (NS+A), or a combination of NS+A and 1-methylcyclopropene (NS+AM), and they were subsequently exposed to ethylene for 24 h. Treatment effectiveness was compared with that of control (CON) flowers, which were kept in distilled water and exposed only to ethylene. The results showed that all treatments significantly improved the postharvest quality and vase life of both rose cultivars. However, NS+AM most markedly delayed senescence and prolonged the vase life of cut flowers by 217% in ‘Matador’ and 168.4% in ‘Dolcetto’, compared with those of CON flowers. NS+AM also effectively increased the flower diameter and maintenance time of positive water balance and initial fresh weight by enhancing solution absorption as well as suppressing bacterial growth at the cut stem ends of the cut roses. Furthermore, NS+AM greatly suppressed the ethylene-inducible increase of ethylene biosynthesis genes and the reduction of ethylene receptor genes in petals, which resulted in a reduced flower response to exogenous ethylene in both rose cultivars. These findings show that NS+AM effectively delays flower senescence in both ethylene sensitive and insensitive cultivars by synergistically preventing ethylene response and water stress in cut flowers. Full article
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Article
Genome-Wide Identification of Strawberry Metal Tolerance Proteins and Their Expression under Cadmium Toxicity
Horticulturae 2022, 8(6), 477; https://doi.org/10.3390/horticulturae8060477 - 27 May 2022
Viewed by 590
Abstract
Metal tolerance proteins (MTPs) are divalent cation transporters, known to upkeep the mineral nutrition of plants and heavy metal transport at cell, tissue, or whole plant levels. However, information related to evolutionary relationships and biological functions of MTP genes in strawberry (Fragaria [...] Read more.
Metal tolerance proteins (MTPs) are divalent cation transporters, known to upkeep the mineral nutrition of plants and heavy metal transport at cell, tissue, or whole plant levels. However, information related to evolutionary relationships and biological functions of MTP genes in strawberry (Fragaria vesca L.) remain elusive. Herein, we identified 12 MTP genes from the strawberry genome and divided them into three main groups (i.e., Zn-MTP, Fe/Zn MTP, and Mn-MTP), which is similar to MTP grouping in Arabidopsis and rice. The strawberry MTPs (FvMTPs) are predicted to be localized in the vacuole, while open reading frame (ORF) length ranged from 1113 to 2589 bp with 370 to 862 amino acids, and possess 4 to 6 transmembrane domains (TMDs), except for FvMTP12 that possessed 16 TMDs. All the FvMTP genes had putative cation efflux and cation diffusion facilitator domains along with a zinc dimerization (ZT-dimer) domain in Mn-MTPs. The collinear analysis suggested their conservation between strawberry and Arabidopsis MTPs. Promoter analysis also demonstrated that some of them might possibly be regulated by hormones and abiotic stress factors. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis proposed that FvMTP genes are involved in cation transport and homeostasis. The expression analysis showed that FvMTP1, FvMTP1.1, and FvMTP4 were significantly induced in leaf samples, while FvMTP1.1 and FvMTP4 were significantly regulated in roots of cadmium (Cd)-treated strawberry plants during progressive stress duration. The findings of Cd accumulation depicted that Cd contents were significantly higher in root tissues than that of leaf tissues of strawberry. These results are indicative of their response during the specific duration in Cd detoxification, while further functional studies can accurately verify their specific role. Full article
(This article belongs to the Special Issue Metabolic Responses to Environmental Stresses in Plants)
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Article
Effect of Saline–Alkali Stress on Sugar Metabolism of Jujube Fruit
Horticulturae 2022, 8(6), 474; https://doi.org/10.3390/horticulturae8060474 - 26 May 2022
Viewed by 483
Abstract
Sugar, an osmoregulatory substance used by plants to adapt to abiotic stresses such as drought and salinity, is one of the most important indexes of fruit quality. In this study, 0–150 mM saline–alkali solutions (NaCl:NaHCO3 = 3:1) were used to irrigate the [...] Read more.
Sugar, an osmoregulatory substance used by plants to adapt to abiotic stresses such as drought and salinity, is one of the most important indexes of fruit quality. In this study, 0–150 mM saline–alkali solutions (NaCl:NaHCO3 = 3:1) were used to irrigate the roots of 10-year-old “Junzao” fruit trees during the growth period to explore the regulation mechanism of different concentrations of saline–alkali stress on sugar and reactive oxygen metabolism in jujube fruit at maturity. The results showed that under low stress (0~90 mM), the contents of sucrose, glucose, and fructose in the jujube fruit and the activities of sucrose phosphate synthase (SPS), sucrose synthase decomposition direction (SS-I), and sucrose synthase synthesis direction (SS-II) increased with increases in stress concentration, results that were consistent with the relative expression trends of the SPS and SS genes; however, the results were reversed under high concentrations (120 and 150 mM). The soluble acid invertase (S-AI) activity decreased with increases in stress concentration under low stress, and the results were reversed with high stress, which was consistent with the relative expression trends of the ZjcINV3, ZjnINV1, and ZjnINV3. Research regarding the response of antioxidant enzymes in fruits under saline–alkali stress showed that only the differences in peroxidase (POD) activity under saline–alkali stress were consistent with sugar accumulation; the proline (PRO), catalase (CAT) decreased and the malondialdehyde (MDA) superoxide dismutase (SOD) increased with increases in saline–alkali stress. These results indicate that the sugar metabolism and antioxidase jointly promote and regulate sugar accumulation in jujube fruits in a low saline–alkali environment. Full article
(This article belongs to the Special Issue Plant Physiology under Abiotic Stresses)
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Article
Involvement of Organic Acid in the Control Mechanism of ε-Poly-L-lysine (ε-PL) on Blue Mold Caused by Penicillium expansum in Apple Fruits
Horticulturae 2022, 8(6), 468; https://doi.org/10.3390/horticulturae8060468 - 25 May 2022
Viewed by 513
Abstract
Blue mold is one of the most serious postharvest diseases in apples caused by Penicillium expansum. The purpose of this study is to determine the effect of ε-poly-L-lysine (ε-PL) on the pathogenicity of P. expansum and explore the potential mechanism from the [...] Read more.
Blue mold is one of the most serious postharvest diseases in apples caused by Penicillium expansum. The purpose of this study is to determine the effect of ε-poly-L-lysine (ε-PL) on the pathogenicity of P. expansum and explore the potential mechanism from the perspective of organic acid. The study investigates the effect of ε-PL treatment on the growth and acid production of P. expansum in vitro and in vivo. When the concentration of ε-PL was 50 mg/L, the growth of P. expansum was inhibited and the decrease in pH value was delayed in the medium. For example, on the third day of culture, P. expansum reduced the pH of the medium from 6.1 to 4.15, and ε-PL inhibited the decrease in the pH value at most 34.4%. When the concentration reached 1000 or 2000 mg/L, the infection of P. expansum in fruits was effectively inhibited. During the growth and infection of P. expansum, gluconic acid is one of the main factors leading to the pH value falling in the local environment. After ε-PL treatment, the accumulation of gluconic acid decreased, the activity of glucose oxidase was suppressed, and then the decline in the local environmental pH slowed down. In addition, after ε-PL treatment, the activities of cell-wall-degrading enzymes, such as cellulase (CL) and polygalacturonase (PG), in the different areas of the P. expansum–apple interaction were also affected by pH change. The results show that ε-PL inhibited the pathogenicity of P. expansum by affecting the accumulation of gluconic acid and slowing the decline in pH in fruit tissues, so as to affect the pathogenicity of P. expansum. This is the first time that the mechanism of ε-PL interfering with the pathogenicity of P. expansum from the perspective of organic acids is clarified. Full article
(This article belongs to the Section Plant Pathology and Disease Management (PPDM))
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Article
A Sustainable Intercropping System for Organically Produced Lettuce and Green Onion with the Use of Arbuscular Mycorrhizal Inocula
Horticulturae 2022, 8(5), 466; https://doi.org/10.3390/horticulturae8050466 - 21 May 2022
Cited by 2 | Viewed by 601
Abstract
Arbuscular mycorrhizal fungi (AMF) are efficient for improving crop production and quality in organic farming systems. Our objective was to examine the effects of two AMF inocula, Rhizophagus intraradices and Diversispora spp., against a non-inoculated control on lettuce and green onion grown organically [...] Read more.
Arbuscular mycorrhizal fungi (AMF) are efficient for improving crop production and quality in organic farming systems. Our objective was to examine the effects of two AMF inocula, Rhizophagus intraradices and Diversispora spp., against a non-inoculated control on lettuce and green onion grown organically in an intercropping cropping system. At time of harvest, colonization levels were very low, and not different compared to the control that was colonized by the native mycorrhizal community. The yield of inoculated lettuce and green onion was unchanged, as also observed in the root system architecture analysis parameters. In both crops, color was not affected, limiting the possibility for consumers to reject the product. Nitrate accumulation was well below the limits set by European Commission in all treatments. Sugar, chlorophyll, K, Na and P contents were also quantified, showing no particular variations. In AMF-treated lettuce, important phytochemical characteristics, such as phenol content and ascorbic acid, showed a tendency for reduced values, while antioxidant capacity was significantly reduced by both AMF treatments. The study provides a description about the effect of AMF on two important co-cultivated crops. Research should be continued in order to determine best matches between plant material and AMF inocula that could result in enhanced production and nutritional quality. Full article
(This article belongs to the Section Vegetable Production Systems)
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Article
Functional Analysis of Two Terpene Synthase Genes Isolated from the Flowers of Hosta ‘So Sweet’
Horticulturae 2022, 8(5), 447; https://doi.org/10.3390/horticulturae8050447 - 17 May 2022
Viewed by 602
Abstract
The Hosta hybrid cultivar ‘So Sweet’, an important ornamental and widely used horticultural plant, is noted for its rich, fragrant white flowers. The main aroma components of Hosta flowers are terpenoids, mainly monoterpenes. Until now, the terpene synthases responsible for terpene production in [...] Read more.
The Hosta hybrid cultivar ‘So Sweet’, an important ornamental and widely used horticultural plant, is noted for its rich, fragrant white flowers. The main aroma components of Hosta flowers are terpenoids, mainly monoterpenes. Until now, the terpene synthases responsible for terpene production in Hosta were not described. In this study, two terpene synthase (TPS) genes (HsTPS1 and HsTPS2) were cloned and characterized to further study their function. Furthermore, the volatile terpenes of Hosta ’So Sweet’ in two flower development stages from two in vitro enzyme tests were analyzed by gas chromatography–mass spectrometry (GC–MS). We analyzed the expression levels of two genes at four different developmental stages using quantitative real-time PCR, while localization was analyzed using Nicotina benthamiana leaves. In vitro, the two proteins were identified to mainly produce linalool and nerol. In addition, the active products of the two recombinant proteins were (E,E)-farnesol and (E,E)-farnesal, respectively, using farnesyl pyrophosphate as a substrate. The high expression of HsTPS1 and HsTPS2 was correlated with the release of components of Hosta flowers. To our knowledge, this is the first time that the terpene synthase genes of Hosta species have been isolated and identified, providing an opportunity to study the terpene metabolic pathways in Hosta species. Full article
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Article
Relation between Rind Pigmentation and Internal Quality of Blood Orange ‘Sanguinelli’: Physicochemical and Sensory Studies
Horticulturae 2022, 8(5), 448; https://doi.org/10.3390/horticulturae8050448 - 17 May 2022
Cited by 2 | Viewed by 546
Abstract
This study evaluated the relation between rind colour and the internal physicochemical and sensory qualities of ‘Sanguinelli’ blood oranges, one of the main blood orange cultivars grown in the Mediterranean region. To this end, 400 fruits were harvested in three different orchards and [...] Read more.
This study evaluated the relation between rind colour and the internal physicochemical and sensory qualities of ‘Sanguinelli’ blood oranges, one of the main blood orange cultivars grown in the Mediterranean region. To this end, 400 fruits were harvested in three different orchards and classified according to rind pigmentation intensity (slight, medium, intense, very intense). All fruits were individually evaluated by determining rind and pulp colour, total soluble solids, acidity, maturity index, juice yield, firmness, and size. Moreover, 71 consumers performed a triangle test to evaluate if fruit sensory properties depended on rind pigmentation. Our results revealed (for the first time) that pulp pigmentation and total soluble solid (TSS) content strongly depend on rind colouration. Among the fruit from the same orchard, the redder the pigmented fruit was (externally) the deeper the red pulp, and the higher the TSS became. This pattern was corroborated in the three orchards under study. Other characteristics, such as acidity, juice yield, firmness, and fruit size, did not depend on external pigmentation. Sensory studies showed that the more coloured the fruit, the higher the accumulated sugar content; consumers perceive these fruits as being sweeter than slightly pigmented ones. This information can be very useful for the citrus industry as external colour may become a quality index for blood oranges, as well as for consumers to make purchase decisions. Full article
(This article belongs to the Special Issue Fruits Quality and Sensory Analysis)
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Article
Pectin-Based Edible Coating Combined with Chemical Dips Containing Antimicrobials and Antibrowning Agents to Maintain Quality of Fresh-Cut Pears
Horticulturae 2022, 8(5), 449; https://doi.org/10.3390/horticulturae8050449 - 17 May 2022
Cited by 1 | Viewed by 568
Abstract
The aim of this study was to assess the effects of pectin coating alone (PE) or combined with chemical dips containing potassium sorbate (PS) or sodium benzoate (SB) as antimicrobials, and N-acetyl cysteine (N-AC) or ascorbic acid (AA) + citric [...] Read more.
The aim of this study was to assess the effects of pectin coating alone (PE) or combined with chemical dips containing potassium sorbate (PS) or sodium benzoate (SB) as antimicrobials, and N-acetyl cysteine (N-AC) or ascorbic acid (AA) + citric acid (CA) as antibrowning agents, on weight loss, color values, browning index, firmness, titratable acidity, soluble solids content, total phenolic content, antioxidant activity and sensory attributes of fresh-cut pears during 15-day storage at 8 °C. Pectin coating delayed weight loss and improved firmness of fresh-cut pears as compared to control samples. Addition of either 1% N-AC or 1% CA + 1% AA in the formulation of the chemical dip protected the phenolic compounds and enhanced the antioxidant activity of fresh-cut pears during storage. PE + 0.2% SB + 1% N-AC and PE + 0.2% PS + 1% N-AC were the most efficient treatments in preserving color and reducing the browning index of fresh-cut pears during 15-day storage at 8 °C and received the highest scores for all sensory attributes throughout 12 days of storage. The results demonstrate the feasibility of PE + 0.2% SB + 1% N-AC and PE + 0.2% PS + 1% N-AC for extending the shelf life of fresh-cut pears. Full article
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Article
Short-Term Pre-Harvest Supplemental Lighting with Different Light Emitting Diodes Improves Greenhouse Lettuce Quality
Horticulturae 2022, 8(5), 435; https://doi.org/10.3390/horticulturae8050435 - 13 May 2022
Cited by 1 | Viewed by 791
Abstract
Winter–spring greenhouse vegetable production is limited by low-level natural light, resulting in decreased growth and quality. To investigate whether short-term pre-harvest supplemental lighting (SL) with light emitting diodes (LEDs) can address this issue, a study was conducted in a greenhouse in Dallas, Texas. [...] Read more.
Winter–spring greenhouse vegetable production is limited by low-level natural light, resulting in decreased growth and quality. To investigate whether short-term pre-harvest supplemental lighting (SL) with light emitting diodes (LEDs) can address this issue, a study was conducted in a greenhouse in Dallas, Texas. Red leaf lettuce (Lactuca sativa L. ‘Red Mist’) plants grown in a hydroponic system were treated with daytime or nighttime SL with red (R) and blue (B) LEDs (RB-LED), blue and UVA LEDs (B/UVA-LED), or white LEDs (W-LED) for three days before harvest and compared to those without SL (control). All SL treatments provided a photon flux density of 167 μmol·m−2·s−1 for 12 h daily. Compared with the control, SL treatments increased leaf thickness and greenness, antioxidant capacity, and concentrations of phytonutrients such as anthocyanins, carotenoids, and total phenolics; however, shoot fresh biomass and total leaf area were generally not affected by SL. There were no differences in all of the above traits among W-LED, RB-LED and B/UVA-LED. Compared with daytime SL, nighttime SL increased leaf greenness and carotenoid concentration. In summary, all three LEDs with different spectra were effective in improving lettuce quality as short-term pre-harvest SL sources and nighttime SL was more effective than daytime SL; however, plant fresh weight and total leaf area were not affected. Full article
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Article
Effects of Fruit Bagging Treatment with Different Types of Bags on the Contents of Phenolics and Monoterpenes in Muscat-Flavored Table Grapes
Horticulturae 2022, 8(5), 411; https://doi.org/10.3390/horticulturae8050411 - 06 May 2022
Viewed by 531
Abstract
The effects of fruit bagging treatments with seven different types of bags on the physicochemical characteristics of three table grape cultivars: RuiduZaohong (RDZH), RuiduHongyu (RDHY), and RuiduHongmei (RDHM) were investigated. Headspace-solid-phase micro-extraction combined with gas chromatography mass spectrometry (HS-SPME-GC-MS) was used to determine [...] Read more.
The effects of fruit bagging treatments with seven different types of bags on the physicochemical characteristics of three table grape cultivars: RuiduZaohong (RDZH), RuiduHongyu (RDHY), and RuiduHongmei (RDHM) were investigated. Headspace-solid-phase micro-extraction combined with gas chromatography mass spectrometry (HS-SPME-GC-MS) was used to determine the compositions of monoterpenes in the fruit. The results showed that the total soluble solids in RDZH and RDHY fruits treated with the transparent, mesh, yellow, white, and blue bags were significantly higher than the control. The sugar–acid ratio of RDZH was optimized under the transparent bag and yellow bag treatments, and both significantly increased the sugar-acid ratio of RDHY and RDHM. Additionally, mesh bag, transparent bag, and white bag improved the contents of phenolics to a certain extent. The most abundant volatiles were linalool, geraniol, β-myrcene, β-cis-ocimene, and β-trans-ocimene, of which linalool was the main aroma component. The least squares discriminant analysis results showed that linalool, 4-terpineol, and terpinolen could be used to distinguish the main contribution of different bagging treatments for RDZH. Trans-isogeraniol, α-terpineol, and terpinolen could be used for RDHY. Trans-isogeraniol, β-myrcene, and terpinolen could be used for RDHM. In conclusion, transparent and white bags promoted the accumulation of phenolics and monoterpenes while pink and blue bags showed inhibitory effects. Full article
(This article belongs to the Section Viticulture)
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Article
RhAGL24 Regulating Auxin-Related Gene RhARF18 Affects Stamen Petaloidy in Rose
Horticulturae 2022, 8(5), 407; https://doi.org/10.3390/horticulturae8050407 - 06 May 2022
Cited by 1 | Viewed by 600
Abstract
AGAMOUS-LIKE 24 (AGL24) is a key gene regulating floral transition, but its involvement in flower organ identity remains largely unknown. In this study, we found that RhAGL24 is strongly related to petal and stamen development in rose. Its expression increases rapidly at the [...] Read more.
AGAMOUS-LIKE 24 (AGL24) is a key gene regulating floral transition, but its involvement in flower organ identity remains largely unknown. In this study, we found that RhAGL24 is strongly related to petal and stamen development in rose. Its expression increases rapidly at the petal primordium development stage and maintains a high level until the complete differentiation stage. RhAGL24 silencing increases the number of malformed petals and decreases the number of stamens, indicating that this gene affects stamen petaloidy. RhAG (AGAMOUS), a class C gene associated with petal and stamen development, is downregulated in RhAGL24-silenced plants. Moreover, we found that RhAGL24 could directly bind to the promoter region of RhARF18 (AUXIN RESPONSE FACTORS 18), a regulator of RhAG. Our results suggested that RhAGL24-RhARF18 module regulates stamen petaloidy in rose and provide new insights into the function of AGL24 for plants. Full article
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Article
OfSPL11 Gene from Osmanthus fragrans Promotes Plant Growth and Oxidative Damage Reduction to Enhance Salt Tolerance in Arabidopsis
Horticulturae 2022, 8(5), 412; https://doi.org/10.3390/horticulturae8050412 - 06 May 2022
Viewed by 498
Abstract
Osmanthus fragrans Lour. is a popular and traditional Chinese decorative plant. Salinity is one of the major abiotic stresses affecting the growth and development of O. fragrans. However, the involvement of the SQUAMOSA PROMOTER BINDING PROTEIN-like (SPL) gene in [...] Read more.
Osmanthus fragrans Lour. is a popular and traditional Chinese decorative plant. Salinity is one of the major abiotic stresses affecting the growth and development of O. fragrans. However, the involvement of the SQUAMOSA PROMOTER BINDING PROTEIN-like (SPL) gene in salt stress response is little understood. To elucidate the role of the OfSPL genes in salt stress resistance, we isolated a candidate gene, OfSPL11, from the O. fragrans genotype ‘Yanhong Gui’. OfSPL11 is a transcriptional activator that is located in the nucleus. OfSPL11 is a salt-inducible gene that is highly expressed in young leaves and shoots, according to tissue-specific expression and external treatment. The promoter activity of OfSPL11 is activated by salt treatments in the leaves of tobacco and callus of O. fragrans. The OfSPL11 transgenic lines exhibited better growth and physiological performance; under salt stress, transgenic lines have a faster germination rate, longer roots, and less leaf withering than the wild type (WT). In addition, OfSPL11 overexpression protected the leaves from oxidative damage by suppressing the accumulation of malondialdehyde (MDA) and reactive oxygen species (ROSs) in Arabidopsis. OfSPL11 overexpression can promote the expression of some genes in response to abiotic stresses, including AtCBL1, AtCOR15A, AtCOR6.6, AtRD29A, AtSOS2 and AtSOS3. Yeast one-hybrid assays and transient expression assays showed that OfZAT12 (homologous to Arabidopsis AtRHL41 gene) specifically binds to the OfSPL11 promoter and positively regulates its expression. This study sheds fresh light on the role of OfSPL11 in enhancing salt tolerance in O. fragrans by promoting growth and reducing oxidative damage. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
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Article
Biostimulatory Action of a Plant-Derived Protein Hydrolysate on Morphological Traits, Photosynthetic Parameters, and Mineral Composition of Two Basil Cultivars Grown Hydroponically under Variable Electrical Conductivity
Horticulturae 2022, 8(5), 409; https://doi.org/10.3390/horticulturae8050409 - 06 May 2022
Viewed by 641
Abstract
Hydroponics is a viable alternative to open field cultivation for year-round vegetable production in urban areas. However, the total dependence on external chemical inputs (fertilizers) makes these systems often less environmentally sustainable. In this perspective, the use of biostimulants could represent a valuable [...] Read more.
Hydroponics is a viable alternative to open field cultivation for year-round vegetable production in urban areas. However, the total dependence on external chemical inputs (fertilizers) makes these systems often less environmentally sustainable. In this perspective, the use of biostimulants could represent a valuable and eco-friendly tool to limit the excessive use of fertilizers without a negative impact on the yield. To this end, our work aimed to evaluate the productive and physiological response of two cultivars of ‘Genovese’ basil (Eleonora and Italiano Classico) for the industrial production of “pesto” grown for 22 days in two nutrient solutions with different electrical conductivity (1 and 2 dS m−1) and the application of two doses of protein hydrolysates (0.15- and 0.30-mL L−1 of Trainer® in the nutrient solution). The mineral profile was evaluated by ion chromatography coupled with a conductivity detector, while pigments were evaluated by UV-Vis spectrophotometry. Generally, the nutrient solution concentration did not significantly affect the fresh yield of the two cultivars tested. On the contrary, the use of the maximum dose of biostimulant (BT2 = 0.30 mL L−1 of nutrient solution) increased fresh yield, leaf area, and ACO2 by 20.7, 27.5, and 17.6%, respectively, compared with the control. Using the lowest dose of biostimulant (BT1 = 0.15 mL L−1 of the nutrient solution) reduced nitrate by 6.6% compared with the control. The results obtained showed that basil cultivation in a floating raft system combined with biostimulant in the nutrient solution could be an excellent solution to improve productivity, reduce nitrate, and cut fertilizer costs. Full article
Article
High-Density Linkage Mapping and Identification of Quantitative Trait Loci Associated with Powdery Mildew Resistance in Flowering Dogwood (Cornus florida)
Horticulturae 2022, 8(5), 405; https://doi.org/10.3390/horticulturae8050405 - 05 May 2022
Viewed by 631
Abstract
Flowering dogwood (Cornus florida L.) is a popular, spring-blooming ornamental tree native to the eastern United States. The species is in general very susceptible to powdery mildew caused by Erysiphe pulchra, which disfigures leaves, decreases growth, and negatively affects flowering. Breeding [...] Read more.
Flowering dogwood (Cornus florida L.) is a popular, spring-blooming ornamental tree native to the eastern United States. The species is in general very susceptible to powdery mildew caused by Erysiphe pulchra, which disfigures leaves, decreases growth, and negatively affects flowering. Breeding for resistance has been recognized as an ideal strategy for controlling the disease in C. florida, but efforts have been hindered by the rarity of PM resistance in available germplasm and knowledge of its genetic control. In this study, we mapped quantitative trait loci (QTL) associated with PM resistance/tolerance in two full sibling populations segregating for PM response: Rutgers H4AR15P25 (P25) × Rutgers H4AR15R28 (P28) (n = 195) and Rutgers H4AR15R25 × Rutgers H4AR15P35 (P35) (n = 83). High-density genetic linkage maps were constructed for the mapping populations using double digest restriction-site associated DNA sequencing-derived single nucleotide polymorphisms (SNPs) and simple sequence repeats (SSRs). The P25 × P28 map consisted of 2265 markers, spanning 1520 cM and 11 linkage groups (LGs) with an average marker spacing of 0.69 cM. The P25 × P35 map was constructed with 1788 markers, spanning 1256 cM and 11 LGs, with an average marker spacing of 0.72 cM. The maps had 604 markers in common and exhibited excellent collinearity. Through multiple QTL model mapping, one major QTL (LOD = 11.36 and R2 = 58.9%) was identified in P25 × P35. Furthermore, a minor QTL (LOD = 3.30 and R2 = 7.8%) was detected in P25 × P28. Due to their proximity onLG3, these QTL may be designating the same locus or tightly linked loci. The negative additive effects of both QTL signify that the PM susceptible male parents were contributing susceptibility alleles to the progeny. This is the first report of QTL associated with PM response on LG3 in C. florida and lays the groundwork for the development of marker-assisted selection for PM resistance in C. florida breeding programs. Full article
(This article belongs to the Topic Plant Breeding, Genetics and Genomics)
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Article
Development of a Highly Sensitive Loop-Mediated Isothermal Amplification Incorporated with Flocculation of Carbon Particles for Rapid On-Site Diagnosis of Blood Disease Bacterium Banana
Horticulturae 2022, 8(5), 406; https://doi.org/10.3390/horticulturae8050406 - 05 May 2022
Viewed by 568
Abstract
Bananas are one of the most crucial fruit crops worldwide and significantly contribute to food security in developing countries. However, blood disease of bananas caused by Ralstonia syzygii subspecies celebensensis has become a threat to banana production. Rapid and accurate diagnosis of BDB [...] Read more.
Bananas are one of the most crucial fruit crops worldwide and significantly contribute to food security in developing countries. However, blood disease of bananas caused by Ralstonia syzygii subspecies celebensensis has become a threat to banana production. Rapid and accurate diagnosis of BDB for on-site detection is pivotal at an early stage for an effective disease control strategy. This study developed LAMP with specific primers targeting BDB, followed by a flocculation assay for visualising positive amplification in the LAMP assay. The assay was sensitive to picogram amounts of gDNA (0.5 pg). LAMP assay on BDB gDNA showed flocculation, but negative results on Fusarium oxysporus cubense and Ralstonia solanacearum confirming the specificity of the assays. Field testing conducted at MARDI headquarters and Taman Pertanian Universiti discovered that the LAMP-flocculation assays were successful in detecting BDB on symptomatic samples as well as on samples from a healthy plot with no symptom observed at the sampling stage, revealing that this assay can detect BDB at an early infection stage. The validation results showed that the LAMP-flocculation assay was comparable with the PCR technique. This newly developed technique is highly specific and sensitive for the early detection of BDB for the adoption of precautionary control measures. Full article
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Article
The Effect of Low-Growing Rootstocks on the Adaptability and Productivity of Sour Cherry Varieties (Prunus cerasus L.) in Arid Conditions
Horticulturae 2022, 8(5), 400; https://doi.org/10.3390/horticulturae8050400 - 02 May 2022
Cited by 1 | Viewed by 640
Abstract
Sour cherry (Prunus cerasus L.), having a rich composition of biologically active connections and antioxidants, is gaining increasing popularity among agricultural producers. Increasing the production of sour cherry fruits requires the introduction of modern technology, one of the elements of which is [...] Read more.
Sour cherry (Prunus cerasus L.), having a rich composition of biologically active connections and antioxidants, is gaining increasing popularity among agricultural producers. Increasing the production of sour cherry fruits requires the introduction of modern technology, one of the elements of which is low-growing rootstocks. For many cultures, the use of low-growing rootstocks has been widely studied, but there is very little information on their use in cherry plantations. We studied new varieties and rootstocks of cherries in the conditions of the dry steppe zone, where this issue had not been studied before. Sour cherry (Prunus cerasus L.) varieties—Toy, Memory of Zhukova, and Loznovskaya—are the most adapted to the conditions in which the experiments were conducted. Russian breeding forms (Krymsk, Krasnodar region), which were taken as rootstocks, are widely used for sweet cherries (Prunus avium L.), but are practically never used for sour cherries (Prunus cerasus L.). The influence of rootstocks on such parameters as drought resistance, heat resistance, winter hardiness, and productivity was studied in variety–rootstock combinations. The study showed that they had the greatest drought resistance, and accordingly affected the grafted variety with rootstock, in the pedigree of which there are wild species. These rootstocks were of the VSL and RVL series. The study of the productivity of variety–rootstock combinations showed that in the grafted varieties the most rapid entry into the fruiting season and the greatest increase in the yield was facilitated by the rootstock forms of VSL-1 and VSL-2 (K5) which made it possible to obtain a yield of 5.8–8.1 kg/tree, depending on the variety grafted onto them. However, it is necessary to continue the research that has been started in order to fully determine the possible qualitative and quantitative parameters of the studied variety–rootstock combinations and to identify the most promising ones for further introduction into industrial production. This work was carried out within the framework of the topic of the state task of the Scientific Research Center of Agroecology of the Russian Academy of Sciences No. 0713-2019-0009: “Theoretical foundations, creation of new competitive biotypes of agricultural crops with high productivity, quality, sustainability and varietal technologies based on the latest methods and technological solutions in a changing climate, including seed breeding and nursery breeding”. Full article
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Article
Effect of Elevated Temperature and Excess Light on Photosynthetic Efficiency, Pigments, and Proteins in the Field-Grown Sunflower during Afternoon
Horticulturae 2022, 8(5), 392; https://doi.org/10.3390/horticulturae8050392 - 28 Apr 2022
Viewed by 742
Abstract
This study examined the photosynthetic responses of two sunflower hybrids to elevated temperatures and excess light intensity in the flowering stage by measuring the chlorophyll a fluorescence (ChlF) under morning and afternoon field conditions to determine the photosynthetic pigment contents and the relative [...] Read more.
This study examined the photosynthetic responses of two sunflower hybrids to elevated temperatures and excess light intensity in the flowering stage by measuring the chlorophyll a fluorescence (ChlF) under morning and afternoon field conditions to determine the photosynthetic pigment contents and the relative accumulation of photosynthetic proteins. The morning environmental conditions were considered optimal, while the afternoon was characterised by elevated temperatures and excess light intensity. The minimum fluorescence intensity (F0), the electron-flux-reducing end electron acceptors at the photosystem I acceptor side per reaction centre (RE0/RC), and the D1 protein had significant, high, and positive correlations with the environmental conditions, which indicates that they were the most useful in the sunflower-stress-response research. In hybrid 7, the elevated temperatures and the excess light intensity resulted in the inactivation of the oxygen-evolving complex, which was indicated by the positive L, K, and J steps, the increase in the maximum quantum yield of PSII (TR0/ABS), the decrease in the electron transport further than the primary acceptor QA (ET0/(TR0-ET0)), the reduction in the performance index (PIABS), and the higher relative accumulation of the light-harvesting complex of the photosystem (LHCII). Hybrid 4 had smaller changes in the fluorescence curves in phases O–J and J–I, and especially in steps L, K, J, and I, and a higher PIABS, which indicates a more efficient excitation energy under the unfavourable conditions. As the tested parameters were sensitive enough to determine the significant differences between the sunflower hybrids in their photosynthetic responses to the elevated temperatures and excess light intensity in the flowering stage, they can be considered useful selection criteria. The development of more adaptable sunflower hybrids encourages sustainable sunflower production under stressful growing conditions. Full article
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Article
Effect on the Growth and Photosynthetic Characteristics of Anthurium andreanum (‘Pink Champion’, ‘Alabama’) under Hydroponic Culture by Different LED Light Spectra
Horticulturae 2022, 8(5), 389; https://doi.org/10.3390/horticulturae8050389 - 28 Apr 2022
Cited by 1 | Viewed by 683
Abstract
Anthurium andreanum was one of the best indoor ornamental plants. Two cultivars of Anthurium andreanum (Pink Champion, Alabama) were used to investigate the effects of light quality on physiological and biochemical indexes. There were six different light quality treatments: Fluorescent Daylight Lamp (CK), [...] Read more.
Anthurium andreanum was one of the best indoor ornamental plants. Two cultivars of Anthurium andreanum (Pink Champion, Alabama) were used to investigate the effects of light quality on physiological and biochemical indexes. There were six different light quality treatments: Fluorescent Daylight Lamp (CK), and RB (100% Blue, 60% R + 40% B, 70% R + 30% B, 80% R + 20% B, 100% Red) provided by light emitting diodes (LED). The results showed that blue light was beneficial to shoot growth and dry matter accumulation, photosynthetic rate, soluble sugar, and POD activities. Red light was beneficial for the synthesis and accumulation of soluble protein, and could promote root growth. ‘Pink Champion’ and ‘Alabama’ obtained the relatively better morphological parameters, chlorophyll contents, photosynthetic parameters, and antioxidant enzyme activities in 7:3 and 6:4 treatments. The antioxidant enzyme (POD, SOD) activities under composite light of red and blue treatments were better than that of monochromatic red, blue light treatments and CK on the whole. Comprehensive evaluation showed that the treatment of 7:3 was a suitable light environment indoors and could be used as the preferred light quality ratio in the production and application of Anthurium andreanum. Full article
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Article
Assessment of Physicochemical, Macro- and Microelements, Heavy Metals, and Related Human Health Risk from Organically, Conventionally, and Homemade Romanian Wines
Horticulturae 2022, 8(5), 382; https://doi.org/10.3390/horticulturae8050382 - 27 Apr 2022
Viewed by 686
Abstract
From the consumers’ perspective, organic and homemade products have become more attractive than conventional ones. However, scientific data regarding the characteristics, properties, and composition of these products are scarce. This study assessed the elemental composition of organic, conventional, and homemade Romanian wines. The [...] Read more.
From the consumers’ perspective, organic and homemade products have become more attractive than conventional ones. However, scientific data regarding the characteristics, properties, and composition of these products are scarce. This study assessed the elemental composition of organic, conventional, and homemade Romanian wines. The physicochemical composition, SO2 (free and total) and total concentration of macroelements, microelements, and heavy metals from nine wine regions containing 165 samples of white (38 organic/70 conventional/57 homemade), 67 red (22/31/14) and 7 rosé (2/2/3) wines were analyzed by inductively coupled plasma mass spectrometry. Dietary intake and target hazard quotient were also evaluated. The phytochemical and elemental compositions of the wine samples varied across regions and wine types. The highest levels of Ca, K, Fe and Al were detected in conventional wines, while homemade wines recorded high concentrations of Na, Mg, V, Ba and Rb. In the case of the rosé wine samples, the levels of trace elements and heavy metals were below the admissible limit. The estimated daily intake of a glass of wine provided less than 0.5% of the tolerable daily intake of the analyzed elements. No health concerns were identified. All wine samples can be safely consumed, regardless of the culture system used for production, and homemade wines are not of a lower quality than organic or conventional wines. Full article
(This article belongs to the Section Viticulture)
Article
Cold Treatment Modulates Changes in Primary Metabolites and Flowering of Cut Flower Tulip Hybrids
Horticulturae 2022, 8(5), 371; https://doi.org/10.3390/horticulturae8050371 - 24 Apr 2022
Viewed by 627
Abstract
Tulip is one of the most important bulbous genera in the world’s floriculture. It is known that cold exposure of bulbs before planting is required to break the bulb dormancy and to promote the plant’s flowering. Preparation procedures performed by breeders differ in [...] Read more.
Tulip is one of the most important bulbous genera in the world’s floriculture. It is known that cold exposure of bulbs before planting is required to break the bulb dormancy and to promote the plant’s flowering. Preparation procedures performed by breeders differ in the duration and the thermal level, and the choice of the procedure depends on the genotype’s sensitivity to temperature; however, little is known about the metabolic responses underlying the different behaviours of the numerous commercial hybrids. We evaluated the influence of two bulb-preparation procedures, 15–18 weeks at 5 ÷ 9 °C, and 9–14 weeks at 2 ÷ 5 °C, in two hybrids of tulip (Tulipa gesneriana L.), ‘Royal Virgin’ and ‘Ad Rem’, grown hydroponically in a floating system. Tulip plants of the two hybrids responded differently to bulb exposure to low temperatures in terms of early flowering, as this was unaffected by the preparation procedure in ‘Royal Virgin’ (27.1 days from transplanting, on average), while it was earlier after treatment at higher temperatures compared with lower temperatures in ‘Ad Rem’ (24.1 vs. 26.7 days at 5 °C vs. at 9 °C). This different flowering earliness may be related to the diverse metabolic responses enacted by the bulbs for cold acclimation that depended on hybrid x thermal treatment. Plant leaf area and flower stem characteristics were similar in the hybrids and were unaffected by the bulb-preparation procedure. Full article
(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)
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Article
Use of Piriformospora indica to Promote Growth of Strawberry Daughter Plants
Horticulturae 2022, 8(5), 370; https://doi.org/10.3390/horticulturae8050370 - 23 Apr 2022
Cited by 1 | Viewed by 623
Abstract
As an endophytic fungus, the growth-promoting effects of Piriformospora indica have been widely confirmed in many of its host plants. In this study, we investigated the influences of P. indica colonization on the growth of the daughter plants of two strawberry cultivars, ‘Benihoppe’ [...] Read more.
As an endophytic fungus, the growth-promoting effects of Piriformospora indica have been widely confirmed in many of its host plants. In this study, we investigated the influences of P. indica colonization on the growth of the daughter plants of two strawberry cultivars, ‘Benihoppe’ and ‘Sweet Charlie.’ The results showed that the fungus colonization significantly promoted the growth of the daughter plants of both of the two strawberry varieties. Its colonization greatly improved almost all of the growth parameters of the ‘Benihoppe’ daughter plants, including the above-ground fresh weight, above-ground dry weight, root fresh weight, root dry weight, plant height, petiole length, leaf area, number of roots and chlorophyll content. However, the fungus colonization showed significant improving effects on only the above-ground fresh weight, root fresh weight and root dry weight of ‘Sweet Charlie.’ Surprisingly, the average root length of ‘Benihoppe’ and ‘Sweet Charlie’ was suppressed by about 14.3% and 24.6%, respectively, by P. indica. Moreover, after P. indica colonization, the leaf nitrate reductase activity and root activity upregulated by 30.12% and 12.74%, and 21.85% and 21.16%, respectively, for the ‘Benihoppe’ and ‘Sweet Charlie’ daughter plants. Our study indicated that P. indica could promote the growth of strawberry daughter plants by improving rooting, strengthening photosynthetic pigments production and nutrient absorption and accelerating biomass accumulation. The fungus shows great potential to be used in the strawberry industry, especially in the breeding of daughter plants. Full article
(This article belongs to the Special Issue Mycorrhizal Roles in Horticultural Plants)
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Article
Genome-Wide Analyses of Tea Plant Stress-Associated Proteins (SAPs) Reveal the Role of CsSAP12 in Increased Drought Tolerance in Transgenic Tomatoes
Horticulturae 2022, 8(5), 363; https://doi.org/10.3390/horticulturae8050363 - 21 Apr 2022
Cited by 1 | Viewed by 629
Abstract
Plant stress-associated proteins (SAPs) contain A20/AN1 zinc finger domains and are involved in plant response to abiotic stresses. In this study, we aimed to explore the biological function of tea plant CsSAPs. A total of 14 CsSAP genes were identified in the tea [...] Read more.
Plant stress-associated proteins (SAPs) contain A20/AN1 zinc finger domains and are involved in plant response to abiotic stresses. In this study, we aimed to explore the biological function of tea plant CsSAPs. A total of 14 CsSAP genes were identified in the tea plant genome using a reference genome database (Camellia sinensis var. sinensis). The CsSAPs were divided into the following two groups: Group I, containing one AN1 domain and/or one A20 domain; and Group II, containing two AN1 domains and/or two C2H2 domains. The sequence alignments and conserved domains analysis indicated that the CsSAPs were highly structurally conserved in terms of amino acid sequence and protein structure. The CsSAPs showed different transcript levels in spatio-temporal expression and in response to cold and drought stress in tea plants. Furthermore, the expression of CsSAP12 was considerably upregulated under drought stress. The overexpression of CsSAP12 in transgenic tomatoes showed increased tolerance to drought stress compared with the wild type. Altogether, the results showed that CsSAP12 might be involved in drought stress. Thus, CsSAP12 might be a target gene in genetic engineering to improve drought tolerance in tea plants. Full article
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Article
Irrigation Levels and Fertilization Rates as Pre-Harvest Factors Affecting the Growth and Quality of Hippeastrum
Horticulturae 2022, 8(4), 345; https://doi.org/10.3390/horticulturae8040345 - 18 Apr 2022
Viewed by 638
Abstract
Growing Hippeastrum in an open field or a greenhouse requires precision irrigation and fertilizer to promote plant growth and development. Therefore, this research aimed to study the effect of irrigation level combined with fertilization rate on the growth and development of Hippeastrum. [...] Read more.
Growing Hippeastrum in an open field or a greenhouse requires precision irrigation and fertilizer to promote plant growth and development. Therefore, this research aimed to study the effect of irrigation level combined with fertilization rate on the growth and development of Hippeastrum. Two experiments were carried out to determine the influence of irrigation and fertilizer on the growth, flowering, and bulb quality of Hippeastrum. In the first experiment, bulbs of Hippeastrum ‘Red Lion’ with circumferences of 25 cm were grown in plastic plots using mixed soil as growing media under a 50% shading net. Plants were irrigated daily until drainage and water contained in macropores by gravity action (Field capacity: FC) for 90 days after planting (DAP) and supplied with three different 15N-15P2O5-15K2O fertilization rates, i.e., 0, 2.5, and 5 g per pot. Plant growth and water use efficiency were measured at 45, 60, and 90 DAP. The results showed that plants supplied with 0 g of fertilizer had the lowest plant height and number of leaves per plant at 90 DAP, whereas there was no significant effect of fertilizer rate treatments on flower quality. The water use efficiency, evapotranspiration rate (ET), crop evapotranspiration under standard condition (ETc), crop coefficient (Kc), photosynthetic rate, and stomatal conductance were decreased when plants were supplied with fertilizer at a rate of 0 g per pot at 90 DAP. In the second experiment, plants were irrigated with four levels, i.e., 100, 75, 50, and 25% ETc combined with three fertilization rates, i.e., 0, 2.5, and 5 g per pot. At 180 DAP, the results showed that water deficit treatment (50 and 25% ETc) decreased plant growth and bulb quality. Irrigation with 100% ETc combined with 2.5 or 5 g per pot and irrigation with 75% ETc combined with 5 g per pot were the optimum levels to promote plant growth and bulb quality in Hippeastrum. Full article
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Article
Growth Characteristics of Lettuce Relative to Generation Position of Air Anions in a Closed-Type Plant Factory
Horticulturae 2022, 8(4), 346; https://doi.org/10.3390/horticulturae8040346 - 18 Apr 2022
Cited by 1 | Viewed by 702
Abstract
(1) Background: We studied how the generation position of air anions in a closed-type plant factory affects the growth characteristics of lettuce and identified the optimal position. (2) Methods: We used LEDs (red/green/blue = 8:1:1) as a light source and set the temperature [...] Read more.
(1) Background: We studied how the generation position of air anions in a closed-type plant factory affects the growth characteristics of lettuce and identified the optimal position. (2) Methods: We used LEDs (red/green/blue = 8:1:1) as a light source and set the temperature and RH of the plant factory to 20 ± 2 ℃ and 50% ± 5%, respectively. We grew lettuce under three air anion conditions—sideward, upward, and downward—and compared the growth characteristics to those of a control grown without air anions. We measured the growth characteristics of the lettuce at 3 and 4 weeks after sowing, and the measurement items were shoot fresh weight (FW) and dry weight (DW); leaf area (LA), length (LL), and width (LW); SPAD; antioxidant capacity; and total phenol content. (3) Results: At 4 weeks, FW in the downward treatment condition was 25.3% higher than in the control, and DW showed a similar difference. LA was about 1943.94 cm²/plant in the downward treatment condition, which was about 15.5% higher than in the control. (4) Conclusions: We conclude that air anion generation has a positive effect on lettuce growth, and the optimal generation position for air anions is downward. Full article
(This article belongs to the Section Vegetable Production Systems)
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Article
The True Identity of the “Second Pollen Morphology” of Camellia oleifera—Stomium Cells
by and
Horticulturae 2022, 8(4), 347; https://doi.org/10.3390/horticulturae8040347 - 18 Apr 2022
Viewed by 535
Abstract
Previous studies on Camellia oleifera pollen morphology have indicated dual morphologies, defined as “dimorphism”. However, they were limited to morphological studies at the end of final development and did not elucidate the origin, structure, and function of the second pollen morphology (striate pollen). [...] Read more.
Previous studies on Camellia oleifera pollen morphology have indicated dual morphologies, defined as “dimorphism”. However, they were limited to morphological studies at the end of final development and did not elucidate the origin, structure, and function of the second pollen morphology (striate pollen). In this study, the differences between the two “pollen” types were compared by paraffin sections, scanning electron microscopy (SEM), fluorescence microscopy, and in vitro germination. The results clearly showed that the second pollen type was formed by stomium cells of the anther, which is responsible for anther dehiscence. The nucleus and vesicles of the stomium cell were specifically distributed during anther development, which may be related to the formation of the septum, pollen dispersal activity, and the increase in stomium cell count; at the microscopic level, the stomium cell mainly consisted of the cell wall, large vesicles, and nucleus. The large vesicles facilitate the rapid dehydration of stomium cells under suitable conditions for anther dehiscence. Furthermore, studies on other species of the genus Camellia have suggested that the second type of pollen morphology is pseudopollen, which is capable of partaking in deceptive pollination. The present study refuted this theory and suggested that the pseudopollen are stomium cells, whose structure relates to their function. These results provide the basis for further research on C. oleifera pollen physiology toward the improvement of pollination rates with agricultural practices or breeding interventions. Full article
(This article belongs to the Section Propagation and Seeds)
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Article
Combining Cultural Tactics and Insecticides for the Management of the Sweetpotato Whitefly, Bemisia tabaci MEAM1, and Viruses in Yellow Squash
Horticulturae 2022, 8(4), 341; https://doi.org/10.3390/horticulturae8040341 - 17 Apr 2022
Viewed by 902
Abstract
The sweetpotato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, [...] Read more.
The sweetpotato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, whitefly-transmitted viruses. The development of a multi-faceted, integrated pest management (IPM) program is needed to increase the sustainability and profitability of squash production. Experiments in 2018 and 2019 evaluated the effects of insect exclusion netting (IEN) in combination with selected pesticides on whitefly population dynamics and virus incidence in greenhouse-grown squash seedlings. Field experiments from 2018 to 2021 evaluated the effects of mulch type (UV-reflective mulch, live mulch, and white plastic mulch), row covers, and insecticides on whitefly population dynamics, silver leaf disorder (SSL) intensity, virus symptom severity, and marketable yield. IEN significantly reduced whiteflies and virus incidence on squash seedlings in the greenhouse study. In the field mulch study, lower whitefly abundance and SSL intensity, as well as reduced virus symptom severity, were observed in plots with reflective mulch compared with white plastic or live mulch. In the insecticide/row cover study, whitefly abundance, SSL intensity, and virus symptom severity were lowest in the row cover and cyantraniliprole- and flupyradifurone-treated plots. Field plots with row covers and those with UV-reflective mulch consistently produced the greatest marketable yields. These findings demonstrate that growers can reduce whitefly and virus pressure and preserve yields in squash production in the southeastern United States by combining cultural and chemical tactics, including row covers, UV-reflective mulch, and select insecticides. Full article
(This article belongs to the Special Issue Implementation of IPM Measures in Vegetable Cropping Systems)
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Article
Impact of Pseudomonas sp. SVB-B33 on Stress- and Cell Wall-Related Genes in Roots and Leaves of Hemp under Salinity
Horticulturae 2022, 8(4), 336; https://doi.org/10.3390/horticulturae8040336 - 15 Apr 2022
Viewed by 653
Abstract
Salinity is a type of abiotic stress that negatively affects plant growth and development. Textile hemp (Cannabis sativa L.) is an important multi-purpose crop that shows sensitivity to salt stress in a genotype- and developmental stage-dependent manner. The root and shoot biomasses [...] Read more.
Salinity is a type of abiotic stress that negatively affects plant growth and development. Textile hemp (Cannabis sativa L.) is an important multi-purpose crop that shows sensitivity to salt stress in a genotype- and developmental stage-dependent manner. The root and shoot biomasses decrease in the presence of NaCl during vegetative growth and several stress-responsive genes are activated. Finding environmentally friendly ways to increase plant health and resilience to exogenous stresses is important for a sustainable agriculture. In this context, the use of beneficial bacteria, collectively referred to as plant growth-promoting bacteria (PGPB), is becoming an attractive and emergent agricultural strategy. In this study, data are provided on the effects of a Pseudomonas isolate (Pseudomonas sp. SVB-B33) phylogenetically closely related to P. psychrotolerans applied via roots to salt-stressed hemp. The application of both living and dead bacteria impacts the fresh weight of the root biomass, as well as the expression of several stress-related genes in roots and leaves. These results pave the way to future investigations on the use of Pseudomonas sp. SVB-B33 in combination with silica to mitigate stress symptoms and increase the resilience to other forms of exogenous stresses in textile hemp. Full article
(This article belongs to the Special Issue Cell Wall Composition and Extract)
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Article
Woody Canker and Shoot Blight Caused by Botryosphaeriaceae and Diaporthaceae on Mango and Litchi in Italy
Horticulturae 2022, 8(4), 330; https://doi.org/10.3390/horticulturae8040330 - 14 Apr 2022
Viewed by 685
Abstract
In recent years, the cultivation of tropical fruit crops has increased in the Mediterranean basin, especially in southern Italy. In surveys conducted from 2014 to 2019 woody canker and shoot blight were observed on mango plants (cvs. Kent, Keitt, Sensation, Osteen, and Kensington [...] Read more.
In recent years, the cultivation of tropical fruit crops has increased in the Mediterranean basin, especially in southern Italy. In surveys conducted from 2014 to 2019 woody canker and shoot blight were observed on mango plants (cvs. Kent, Keitt, Sensation, Osteen, and Kensington Pride) and litchi plants (cvs. Way Chee and Kwai Mai Pink) cultivated in Sicily. Botryosphaeriaceae and Diaporthaceae were consistently isolated from symptomatic samples. Morphological characterization and multi-locus phylogenies using three genomic loci (a portion of translation elongation factor 1-α gene, a portion of the β-tubulin gene, and an internal transcribed spacer) identified these fungi as Neofusicoccum parvum, Lasiodiplodia theobromae, Botryosphaeria dothidea, Diaporthe foeniculina, and Diaporthe baccae on mango and Diaporthe foeniculina and Diaporthe rudis on litchi. Pathogenicity tests on healthy mango (cv. Kensington Pride) and litchi (cv. Way Chee) plants demonstrated the pathogenicity of the isolates used in the study, and Koch’s postulates were fulfilled for all pathogens. To our knowledge, this is the first report of L. theobromae, B. dothidea, and Diaporthe species on mango in Italy and the first report worldwide of woody canker and shoot blight caused by D. foeniculina and D. rudis on litchi plants. Full article
(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)
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Article
Genetic Analysis of the Grapevine GATA Gene Family and Their Expression Profiles in Response to Hormone and Downy Mildew Infection
Horticulturae 2022, 8(4), 303; https://doi.org/10.3390/horticulturae8040303 - 03 Apr 2022
Viewed by 669
Abstract
Grapevine (Vitis. vinifera L.) is one of the most economically important fruit crops throughout the world. However, grape production is increasingly impacted by numerous diseases, including downy mildew, caused by the oomycete Plasmopara viticola. In grapevine and other plants, members of [...] Read more.
Grapevine (Vitis. vinifera L.) is one of the most economically important fruit crops throughout the world. However, grape production is increasingly impacted by numerous diseases, including downy mildew, caused by the oomycete Plasmopara viticola. In grapevine and other plants, members of the GATA family of transcription factors play key roles in light and phytohormone signaling. However, little is known about their potential roles in biotic defense responses. As a first step, we identified 27 GATA transcription factors in grapevine and defined their transcriptional responses to three biotic stress-related phytohormones (SA, MeJA, and BR) in callus cells, and challenge with P. viticola in a downy mildew-sensitive cultivar, V. vinifera ‘Pinot noir’, and a resistant cultivar, V. piasezkii ‘Liuba-8′. Many of the VvGATA genes had higher expression at 0.5 h after hormones treatments. Moreover, a group of VvGATAs was dramatically induced in ‘Liuba-8′ at 24 post infection by P. viticola. However, the same genes were significantly repressed and showed low expression levels in ‘Pinot noir’. Additionally, VvGATA27 was located in the nucleus and had transcriptional activity. Taken together, the study identified the GATA full gene families in grapes on phylogenetic analysis and protein structure. Moreover, this study provided a basis for discussing the roles of VvGATAs in response to hormones and P. viticola infection. Our results provided evidence for the selection of candidate genes against downy mildew and lay the foundation for further investigation of VvGATA transcription factors. Full article
(This article belongs to the Special Issue Stress Biology of Horticultural Plants)
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Article
Application of an Alternative Nutrient Replenishment Method to Electrical Conductivity-Based Closed-Loop Soilless Cultures of Sweet Peppers
Horticulturae 2022, 8(4), 295; https://doi.org/10.3390/horticulturae8040295 - 30 Mar 2022
Viewed by 700
Abstract
The nutrient replenishment method primarily impacts the nutrient variations in a closed-loop soilless culture system. However, there is still a lack of systematic approaches for the effective way of nutrient replenishment. Our previous study theoretically derived and experimentally validated an alternative nutrient replenishment [...] Read more.
The nutrient replenishment method primarily impacts the nutrient variations in a closed-loop soilless culture system. However, there is still a lack of systematic approaches for the effective way of nutrient replenishment. Our previous study theoretically derived and experimentally validated an alternative nutrient replenishment method expecting synchronized total fertilizer supply to total nutrient absorption by crops and lower concentration fluctuations than conventional methods. However, no individual nutrient management has been performed. The objective of this study was to apply individual nutrient management to the alternative nutrient replenishment technique under experimental- and commercial-scale electrical conductivity (EC)-based closed-loop soilless cultures. Automated nutrient solution mixing modules and sweet peppers grown on rockwool slabs were used. Nutrient concentrations and crop productivity were compared between the closed-loop system using the alternative nutrient replenishment and the conventional open-loop systems. During early treatment, rapid decreases in K+ and H2PO4 were observed in the closed-loop system. However, after the stock solution nutrient adjustment, the decreasing trend was stabilized and returned close to initial concentrations. No significant differences in sugar content, incidence of blossom-end rot, and productivity of sweet peppers were observed between the closed- and open-loop soilless cultures. We confirmed that the nutrient variation stabilizing effect of the alternative nutrient replenishment method was valid under nutrient adjustment conditions and had comparable nutrient management performance with the open-loop system. Full article
(This article belongs to the Special Issue Hydroponics in Vegetable Production)
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Article
Willingness-to-Pay for Produce: A Meta-Regression Analysis Comparing the Stated Preferences of Producers and Consumers
Horticulturae 2022, 8(4), 290; https://doi.org/10.3390/horticulturae8040290 - 29 Mar 2022
Viewed by 667
Abstract
Willingness-to-pay (WTP) estimates help agribusinesses estimate whether a new product is likely to be profitable. For produce, new products, such as new fruit varieties, need to be adopted by producers before they can be sold to consumers. The study of ex ante fruit [...] Read more.
Willingness-to-pay (WTP) estimates help agribusinesses estimate whether a new product is likely to be profitable. For produce, new products, such as new fruit varieties, need to be adopted by producers before they can be sold to consumers. The study of ex ante fruit and vegetable producer preferences is relatively new. This study uses meta-regression analysis to compare the estimated WTP premium between U.S. producers and consumers to determine whether they differ. After controlling for differences in study methods, product attributes, and potential publication bias, the producer WTP was between 14.16 and 27.73 percentage points higher. Subject to several caveats and limitations, this suggests that consumer WTP can be a sufficient metric for the profitability of new produce products. Full article
(This article belongs to the Special Issue Economics and Management of Fruit and Vegetable Production)
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Article
Weather Conditions Influence on Lavandin Essential Oil and Hydrolate Quality
Horticulturae 2022, 8(4), 281; https://doi.org/10.3390/horticulturae8040281 - 27 Mar 2022
Cited by 4 | Viewed by 702
Abstract
Lavandula sp. essential oil and hydrolate are commercially valuable in various industry branches with the potential for wide-ranging applications. This study aimed to evaluate the quality of these products obtained from L. x intermedia cv. ‘Budrovka’ for the first time cultivated on Fruška [...] Read more.
Lavandula sp. essential oil and hydrolate are commercially valuable in various industry branches with the potential for wide-ranging applications. This study aimed to evaluate the quality of these products obtained from L. x intermedia cv. ‘Budrovka’ for the first time cultivated on Fruška Gora Mt. (Serbia) during three successive seasons (2019, 2020, and 2021). Essential oil extraction was obtained by steam distillation, and the composition and influence of weather conditions were also assessed, using flowering tops. The obtained essential oils and hydrolates were analysed by gas chromatography with a flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). A linear regression model was developed to predict L. x intermedia cv. ‘Budrovka’ essential oil volatile compound content and hydrolate composition during three years, according to temperature and precipitation data, and the appropriate regression coefficients were calculated, while the correlation analysis was employed to analyse the correlations in hydrolate and essential oil compounds. To completely describe the structure of the research data that would present a better insight into the similarities and differences among the diverse L. x intermedia cv. ‘Budrovka’ samples, the PCA was used. The most dominant in L. intermedia cv. ‘Budrovka’ essential oil and hydrolate were oxygenated monoterpenes: linalool, 1,8-cineole, borneol, linalyl acetate, and terpinene-4-ol. It is established that the temperature was positively correlated with all essential oil and hydrolate compounds. The precipitations were positively correlated with the main compounds (linalool, 1,8-cineole, and borneol), while the other compounds’ content negatively correlated to precipitation. The results indicated that Fruška Gora Mt. has suitable agro-ecological requirements for cultivating Lavandula sp. and providing satisfactory essential oil and hydrolate. Full article
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Article
Producing Cherry Tomatoes in Urban Agriculture
Horticulturae 2022, 8(4), 274; https://doi.org/10.3390/horticulturae8040274 - 22 Mar 2022
Viewed by 867
Abstract
Agriculture in urban and urbanizing areas will be increasingly critical to enhancing food security and food sovereignty, creating income, strengthening social interactions, and improving health outcomes in cities. We used three roofs, a hydroponic system, an aquaponic system, and field rows in an [...] Read more.
Agriculture in urban and urbanizing areas will be increasingly critical to enhancing food security and food sovereignty, creating income, strengthening social interactions, and improving health outcomes in cities. We used three roofs, a hydroponic system, an aquaponic system, and field rows in an urban environment to grow six dwarf tomato cultivars: ‘Micro Tom’, ‘Red Robin’, ‘Sweet ‘n’ Neat’, ‘Terenzo’, ‘Tiny Tim’, and ‘Tumbler.’ We measured the marketable yield and non-marketable yield, mass of non-marketable tomatoes exhibiting defects, and the content of 12 mineral nutrients in fruits. We found the productivity often varied among cultivars within a cropping system. ‘Terenzo’ and ‘Tumbler’ were always some of the most productive cultivars, whereas ‘Micro Tom’ was normally among the least productive cultivars. The production from ‘Red Robin’, ‘Tiny Tim’, and ‘Sweat ‘n’ Neat’ was more variable, sometimes producing high, moderate, or low mass. The mineral content was especially variable across the cultivars and we did not identify cultivars that were consistently high or low in mineral content across systems, indicating that the mineral content was highly influenced by a genotype x environment interaction. The amount of 5 minerals differed across cultivars in aquaponics, 9 differed in hydroponics, and 6–12 differed in the roof systems. A high-yielding cultivar should be selected first and production methods can then be modified to maximize the nutrient content. Full article
(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)
Article
Characterization of Young Shoot Population, Yield, and Nitrogen Demands of Tea (Camellia sinensis L.) Harvested under Different Standards
Horticulturae 2022, 8(4), 275; https://doi.org/10.3390/horticulturae8040275 - 22 Mar 2022
Viewed by 637
Abstract
The quality of green tea is greatly influenced by the harvest standards for young shoots. The present field experiment was conducted to characterize the young shoot populations, yields, and nitrogen (N) demands of tea plants subjected to four different harvest standards, i.e., buds [...] Read more.
The quality of green tea is greatly influenced by the harvest standards for young shoots. The present field experiment was conducted to characterize the young shoot populations, yields, and nitrogen (N) demands of tea plants subjected to four different harvest standards, i.e., buds with one, two, or three young expanding leaves (referred to as B1L, B2L, and B3L, respectively) and a combination of B1L and B3L (B1L/B3L) throughout the year. Weight per shoot was closely related to the number of expanding leaves and was greater in B3L than B1L and B2L, and also greater in summer and autumn than in spring, whereas B1L revealed the greatest young shoot density and highest N concentration. Annual shoot yield and shoot N content were largest in B3L and decreased in the following order: B3L > B2L ≈ B1L/B3L > B1L. However, in the early spring the shoot density, yield, and shoot N content of B1L were much higher than those of B3L. The harvest of B3L significantly reduced the biomass of brown roots and its ratio against the above-ground biomass compared to other harvest standards, suggesting a decreased allocation of carbon to the root system due to seasonal removal. The N dilution curve (Nys = a × Yysb, where Nys is the shoot N content and Yys is the shoot yield) of spring tea differed markedly from those of summer and autumn teas, suggesting different coordination properties for shoot growth and N supply among the seasons. The annual harvest index (NHI) measured by 15N traces ranged between 0.18 and 0.23, indicating relatively low N allocation to young shoots, whereby large proportions (58.2–66.9% of the total 15N absorption) remained in the plant at the end of the experiment. In conclusion, the seasonal distribution of the shoot density, weight per shoot, yield, and N demands vary with harvest standards and highlight the importance of N precision management in tea production to be finely tuned to meet the changes in harvest season and requirements. Full article
(This article belongs to the Special Issue Advances in Tea Plant Biology and Tea Quality Regulation)
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Article
Converting Apple Textural Parameters Obtained from Penetrometers and Their Relationships with Sensory Attributes
Horticulturae 2022, 8(3), 269; https://doi.org/10.3390/horticulturae8030269 - 20 Mar 2022
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Abstract
Textural attributes of apple impact consumers’ acceptance of the fruit, and are frequently measured by researchers and industry experts to evaluate the fruit quality at different stages of production and marketing. Various instruments are used to conduct these textural evaluations in research and [...] Read more.
Textural attributes of apple impact consumers’ acceptance of the fruit, and are frequently measured by researchers and industry experts to evaluate the fruit quality at different stages of production and marketing. Various instruments are used to conduct these textural evaluations in research and industry settings. The application of different instruments makes the comparison and integration of results extremely difficult. The main objectives of this study were to compare data obtained from three widely used textural instruments, investigate their relationships with each other and with sensory evaluations, and develop models to convert data among instruments. Three penetrometers were included in the study: (1) Fruit Texture Analyzer (FTA); (2) Mohr Digi-Test-2 (MDT-2); and (3) TA.XTplus Texture Analyzer (TA.XTplus). Eight apple varieties with a range of textural attributes were selected. Eleven sensory judges evaluated three apple slices (1/8 apple) from each variety. The instrumental measurements were conducted on 10 apples per instrument from each variety, with two measurements on each apple. Results of principal component analysis indicated that 95.82% of the variation in the texture data could be explained using only two principal components. Linear and nonlinear regression models were developed to convert data obtained from an instrument to those from other instruments. Full article
(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)
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Article
Integrative Effects of CO2 Concentration, Illumination Intensity and Air Speed on the Growth, Gas Exchange and Light Use Efficiency of Lettuce Plants Grown under Artificial Lighting
Horticulturae 2022, 8(3), 270; https://doi.org/10.3390/horticulturae8030270 - 20 Mar 2022
Cited by 1 | Viewed by 694
Abstract
This study investigates and quantifies the integrative effects of CO2 concentration (500, 1000 and 1500 µmol mol−1), illumination intensity (100, 200 and 300 μmol m−2 s−1) and air speed (0.25, 0.50 and 0.75 m s−1) [...] Read more.
This study investigates and quantifies the integrative effects of CO2 concentration (500, 1000 and 1500 µmol mol−1), illumination intensity (100, 200 and 300 μmol m−2 s−1) and air speed (0.25, 0.50 and 0.75 m s−1) on the growth, gas exchange and light use efficiency of lettuce plants (Lactuca sativa L.) grown under artificial lighting. The results show that lettuce growth and gas exchange are closely related to CO2 concentration and illumination intensity, while air speed enhances CO2 transport during photosynthesis. The most influential two-way interactions were observed between CO2 concentration and illumination intensity on the fresh and dry weights of lettuce shoots with effect sizes of 34% and 32%, respectively, and on the photosynthesis, transpiration and light use efficiency, with effect sizes of 52%, 47% and 41%, respectively. The most significant three-way interaction was observed for the photosynthetic rate, with an effect size of 51%. In general, the fresh and dry weights of lettuce plants increased by 36.2% and 20.1%, respectively, with an increase in CO2 concentration from 500 to 1500 µmol mol−1 and by 48.9% and 58.6%, respectively, with an increase in illumination intensity from 100 to 300 μmol m2 s−1. The photosynthetic rate was found to be positively correlated with CO2 concentration, illumination intensity and air speed. The transpiration rate and stomatal conductance increased by 34.9% and 42.1%, respectively, when the illumination intensity increased from 100 to 300 μmol m−2 s−1. However, as CO2 concentration increased from 500 to 1500 μmol mol−1 and air speed increased from 0.25 to 0.75 m s−1, the transpiration rate decreased by 17.5% and 12.8%, respectively. With the quantified data obtained, we were able to adequately determine how CO2 concentration, illumination intensity and air speed interact with their combined effects on the growth of lettuce plants grown in indoor cultivation systems with artificial lighting. Full article
(This article belongs to the Section Vegetable Production Systems)
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Article
VIS-NIR Modeling of Hydrangenol and Phyllodulcin Contents in Tea-Hortensia (Hydrangea macrophylla subsp. serrata)
Horticulturae 2022, 8(3), 264; https://doi.org/10.3390/horticulturae8030264 - 18 Mar 2022
Cited by 2 | Viewed by 833
Abstract
Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built [...] Read more.
Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built using a partial least squares regression (PLSR). While HG is common in Hydrangea macrophylla, PD only occurs in cultivars of Hydrangea macrophylla subsp. serrata, also known as ‘tea-hortensia’. PD content varies significantly over the course of the growing period. For maximizing yield, a targeted estimation of PD content is needed. Nowadays, DHC contents are determined via UPLC, a time-consuming and a destructive method. In this research article we investigated PLSR-based models for HG and PD using three different spectrometers. Two separate trials were conducted to test for model quality. Measurement conditions, namely fresh or dried leaves and black or white background, did not influence model quality. While highly accurate modeling of HG and PD for single plants was not possible, the determination of the mean content on a larger scale was successful. The results of this study show that hyperspectral modeling as a decision support for farmers is feasible and provides accurate results on a field scale. Full article
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