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Horticulturae, Volume 9, Issue 2 (February 2023) – 166 articles

Cover Story (view full-size image): The use of synthetic fungicides has raised questions about their future safety and effectiveness due to the effects on ecosystems and emergence of resistant strains. Plant by-products, particularly garlic peel extract (GPE), can serve as effective and safe alternatives because they are biodegradable and decrease the emergence of resistance due to the multi-target mechanism of action. In vitro tests have indicated that GPE was effective against several phytopathogenic fungi, and ex situ assays on apples showed that GPE can significantly reduce lesions caused by Colletotrichum acutatum. The results also suggest that GPE affects the plasma membrane and cell wall, potentially targeting ergosterol biosynthesis and cell wall remodeling, making it a promising biorational candidate for use in agriculture. View this paper
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13 pages, 1137 KiB  
Article
Chemical Composition, and Antioxidant and Cholinesterase Inhibitory Activities of Lindera glauca Fruit Essential Oil and Molecular Docking Studies of Six Selected Compounds
by Zhenchun Sun, Xiankun Su, Yechun Lin, Chongyan Long, Yazhou Zhang and Tianming Zhao
Horticulturae 2023, 9(2), 289; https://doi.org/10.3390/horticulturae9020289 - 20 Feb 2023
Cited by 5 | Viewed by 1720
Abstract
Lindera glauca is a shrub or small tree mostly distributed in China, Japan and Korea. However, reports on the biological activities of Lindera glauca fruit essential oil (LGFEO) are limited. The study on its chemical composition, and antioxidant and cholinesterase inhibitory activities were [...] Read more.
Lindera glauca is a shrub or small tree mostly distributed in China, Japan and Korea. However, reports on the biological activities of Lindera glauca fruit essential oil (LGFEO) are limited. The study on its chemical composition, and antioxidant and cholinesterase inhibitory activities were performed, along with molecular docking of six selected compounds. The LGFEO was extracted by hydro distillation and analyzed by GC-MS and GC-FID. Antioxidant activities of LGFEO were evaluated by three methods with different mechanisms. Acetylcholinesterase and butyrylcholinesterase inhibitory activities of LGFEO were tested. A total of 48 components were identified representing 95.74% of the total composition of LGFEO in which the major compounds were (E)-β-ocimene (41.53%), α-copaene (13.17%), δ-cadinene (6.20%), 3-carene (5.89%) and eucalyptol (3.57%). Weak antioxidant activities of LGFEO in three assays (9.52, 11.36 and 38.98 μmol TE/g, respectively) were observed. LGFEO showed obvious cholinesterase inhibitory activities at the final concentrations of 50 and 20 μg/mL. IC50 values for acetylcholinesterase and butyrylcholinesterase were 46.48 and 34.85 μg/mL, respectively. Molecular docking revealed that geranyl acetate, β-caryophyllene and limonene had lower binding affinities in the range of −7.1 to −6.1 kcal/mol through hydrophobic interactions and hydrogen bond. Six compounds including 3-carene, limonene, eucalyptol, (E)-β-ocimene, geranyl acetate and β-caryophyllene could contribute together to cholinesterase inhibitory activities of LGFEO. This essential oil indicated low potential as natural antioxidant, but it could be potentially used as cholinesterase inhibitor with possible application in food, aromatherapy and pharmaceutical industries. Full article
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18 pages, 587 KiB  
Review
Anthocyanin Accumulation in Berry Fruits and Their Antimicrobial and Antiviral Properties: An Overview
by Aistis Petruskevicius, Jonas Viskelis, Dalia Urbonaviciene and Pranas Viskelis
Horticulturae 2023, 9(2), 288; https://doi.org/10.3390/horticulturae9020288 - 20 Feb 2023
Cited by 11 | Viewed by 4439
Abstract
Because of the recent global crises and lifestyle trends, anthocyanin-rich fruits are receiving more attention due to their medicinal qualities. Many studies have concluded that higher anthocyanin consumption tends to correlate with health benefits. Furthermore, research has shown great promise for anthocyanin application [...] Read more.
Because of the recent global crises and lifestyle trends, anthocyanin-rich fruits are receiving more attention due to their medicinal qualities. Many studies have concluded that higher anthocyanin consumption tends to correlate with health benefits. Furthermore, research has shown great promise for anthocyanin application in treating fever and neurodegenerative processes. Once the industrial application difficulties are solved, anthocyanins might prove to be a crucial component in helping to treat the diseases that are becoming more common—viral infections and illnesses associated with aging. Fruit extracts that contain large quantities of anthocyanins have antimicrobial and antiviral (against SARS-CoV-2 virus) properties. Most of the synthesized anthocyanins in the fruit-bearing fruits are stored in the fruits. The aim of this review article is to indicate the fruit species that have the most potential for anthocyanin extraction from fruits, to overview the antimicrobial and antiviral capabilities of anthocyanin and the main sample preparation and extraction methods that preserve polyphenolic compounds and reduce the time expenditure. Full article
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16 pages, 7308 KiB  
Article
Effects of Nutrition and Light Quality on the Growth of Southern Highbush Blueberry (Vaccinium corymbosum L.) in an Advanced Plant Factory with Artificial Lighting (PFAL)
by Haishan An, Jiaying Zhang, Liqing Zhang, Shuigen Li, Boqiang Zhou and Xueying Zhang
Horticulturae 2023, 9(2), 287; https://doi.org/10.3390/horticulturae9020287 - 20 Feb 2023
Cited by 4 | Viewed by 2914
Abstract
A plant factory is a highly developed product system that can produce higher yields and better quality plants under controlled conditions. However, knowledge of blueberry cultivation in plant factories is limited. This study established an advanced plant factory with artificial lighting (PFAL) and [...] Read more.
A plant factory is a highly developed product system that can produce higher yields and better quality plants under controlled conditions. However, knowledge of blueberry cultivation in plant factories is limited. This study established an advanced plant factory with artificial lighting (PFAL) and investigated the effects of nutrition supply and light qualities on the growth performance of blueberries. Different nutrition treatments affected the vegetative growth of blueberries in PFAL, especially the new shoot length and number. Exogenous fertilization significantly promoted the uptake of N, P, and K elements, and a nutrition solution with N:P:K = 2:1:1 was suggested to be superior for blueberries in PFAL. Red light facilitated vegetative growth to some degree, and the blue light was conducive to increased chlorophyll and anthocyanin content. The Pn value was significantly enhanced under 60% red plus 40% blue light. Combining red and blue light is more beneficial to blueberry growth and might be a preferential strategy in PFAL. This study is the first to investigate the growth performance of blueberries cultivated in PFAL, which can provide an important theoretical database for blueberry cultivation in a plant factory with artificial lighting. Full article
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6 pages, 1305 KiB  
Correction
Correction: Bao, W.; Shen, Y. Dynamic Changes on Floral Aroma Composition of the Three Species from Tilia at Different Flowering Stages. Horticulturae 2022, 8, 719
by Wenqin Bao and Yongbao Shen
Horticulturae 2023, 9(2), 286; https://doi.org/10.3390/horticulturae9020286 - 20 Feb 2023
Viewed by 785
Abstract
In the original publication [...] Full article
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17 pages, 2783 KiB  
Article
Synergistic Impact of Melatonin and Putrescine Interaction in Mitigating Salinity Stress in Snap Bean Seedlings: Reduction of Oxidative Damage and Inhibition of Polyamine Catabolism
by Hossam S. El-Beltagi, Ahmed Abou El-Yazied, Hany G. Abd El-Gawad, Mahmoud Kandeel, Tarek A. Shalaby, Abdallah Tageldein Mansour, Nadi Awad Al-Harbi, Salem Mesfir Al-Qahtani, Abdulmalik A. Alkhateeb and Mohamed F. M. Ibrahim
Horticulturae 2023, 9(2), 285; https://doi.org/10.3390/horticulturae9020285 - 20 Feb 2023
Cited by 12 | Viewed by 2129
Abstract
While the individual influences of melatonin (MT) and polyamines (PAs) have been widely studied under various abiotic stresses, little is known about their interaction under salinity stress. In the present study, salt stress applied by 50 mM of sodium chloride (NaCl) on snap [...] Read more.
While the individual influences of melatonin (MT) and polyamines (PAs) have been widely studied under various abiotic stresses, little is known about their interaction under salinity stress. In the present study, salt stress applied by 50 mM of sodium chloride (NaCl) on snap bean seedlings has been supplemented with 20 μM of MT and/or 100 μM of putrescine (Put) (individually and in combination). The results indicated that under salinity stress, the combination of MT + Put achieved the highest significant increase in shoot fresh and dry weight, chlorophyll (Chl a), Chl a + b, carotenoids, total soluble sugars, proline, K, Ca, and cell membrane stability index (CMSI), as well as catalase (CAT) and peroxidase (POX) activities. This improvement was associated with an obvious decrease in Na, Na/K ratio, and oxidative damage as indicated by reducing leaf contents of methylglyoxal (MG), hydrogen peroxide (H2O2), and the rate of lipid peroxidation (malondialdehyde; MDA). Moreover, the combination of MT + Put demonstrated a significant decrease in the activities of diamine oxidase (DAO) and polyamine oxidase (PAO) leading to the reduction of the rate of polyamine oxidation. Meanwhile, MT applied individually gave the highest significant increase in leaf relative water content (RWC), Chl b, superoxide dismutase (SOD), and ascorbate peroxidase (APX). Conclusively, the combination treatment of MT + Put could decrease the degradation of polyamines and enhance tolerance to salinity stress in snap bean seedlings. Full article
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14 pages, 4065 KiB  
Article
Ozone-Ultrafine Bubbles for Reducing Concentration of Citric Acid and Sodium Chloride for Trimmed Young Coconut Preservation
by Supat Pathomaim, Suwatchai Jarussophon, Siwaret Arikit and Wachiraya Imsabai
Horticulturae 2023, 9(2), 284; https://doi.org/10.3390/horticulturae9020284 - 20 Feb 2023
Cited by 1 | Viewed by 2225
Abstract
Citric acid (CA) and sodium chloride (NaCl) are used in organically trimmed young aromatic coconuts to prevent microbial growth and browning. However, the use of high concentrations of these chemicals is considered a waste and may elicit allergic reactions in the operator. This [...] Read more.
Citric acid (CA) and sodium chloride (NaCl) are used in organically trimmed young aromatic coconuts to prevent microbial growth and browning. However, the use of high concentrations of these chemicals is considered a waste and may elicit allergic reactions in the operator. This study aimed to reduce the concentration of these two substances by using a combination of ozone-ultrafine bubbles (O3UFBs). The trimmed young coconuts were dipped in 20% CA + 20% NaCl (commercial method; C20N20), 20% CA + 10% NaCl + O3UFBs (C20N10-O3UFBs), and 15% CA + 15% NaCl + O3UFBs (C15N15-O3UFBs) for one minute. All the coconuts were wrapped with PVC film and stored at 2–4 °C for 30 days and then transferred to storage at 8–10 °C for 7 days. The quality of the coconut water and coconut meat was evaluated. The whiteness, browning index, polyphenol oxidase (PPO) activity, and total phenolic content of coconut mesocarp were investigated. Titratable acidity and the total soluble solid content of coconut water were 0.038–0.095% and 6.65–7.40 °Brix, respectively, while that of the coconut meat was 0.044–0.104% and 8.00–9.80 °Brix, respectively. The mesocarp whiteness, browning index, disease score, fruit appearance, PPO activity, and total phenolic content did not differ among the treatments. C20N10-O3UFBs and C15N15-O3UFBs treatments also controlled microbial growth and the surface browning of the trimmed coconuts. In conclusion, the use of O3UFBs decreased the concentration of CA and NaCl by at least 25% of the commercial method used for treating trimmed young coconuts. Full article
(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)
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12 pages, 3035 KiB  
Article
Genome Polymorphism Analysis and Selected Sweep Regions Detection via the Genome Resequencing of 91 Cabbage (Brassica oleracea) Accessions
by Qiang Li, Yumei Cai, Guoli Zhang, Liqiang Gu, Ying Wang, Yuqian Zhao and Shamsiah Abdullah
Horticulturae 2023, 9(2), 283; https://doi.org/10.3390/horticulturae9020283 - 19 Feb 2023
Viewed by 1617
Abstract
The completion of more and more high-quality cabbage genome sequencing attempts provides an important reference genome sequence for resequencing a large proportion of B. oleracea populations. This has laid a foundation for the study of the population diversity of B. oleracea and the [...] Read more.
The completion of more and more high-quality cabbage genome sequencing attempts provides an important reference genome sequence for resequencing a large proportion of B. oleracea populations. This has laid a foundation for the study of the population diversity of B. oleracea and the excavation of genes related to important agronomic traits. Here, we performed genome resequencing of 91 B. oleracea accessions from 14 countries. We produced a total of 983.84 Gb of high-quality sequencing data, and the average sequencing depth of the genomes was over 15.71 among the 91 accessions. A total of 3,432,341 high-quality SNPs were detected in these B. oleracea accessions. A phylogenetic tree indicated that the leaf ball shapes of “Gaobian” accessions and most “Jianqiu” accessions converge with “Bianqiu” accessions, while “Yuanqiu” accessions were individually assigned to a branch. The principal component analysis (PCA) result was consistent with the phylogenetic relationships. The LD distance of “Yuanqiu” was 38.69 Kb, while that of “Bianqiu” was 30.16 Kb. This result indicated that the linkage degree of the “Yuanqiu” population is greater than that of the “Bianqiu” population, which may indicate that the “Yuanqiu” population has received more positive selection. Our analysis showed that, for the 91 accessions, the best population structure number was four. A total of 560 genes were identified across the 203 selected sweep regions identified in the “Yuanqiu” accessions. Similarly, 682 genes were identified across the 304 selective sweep regions in the “Bianqiu” accessions. Finally, several functional terms were identified via enrichment analysis of the genes in the selective sweep regions. In conclusion, this study will provide rich resources for studies on gene function related to leaf ball development and the population diversity of B. olearcea. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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14 pages, 5309 KiB  
Article
Brcd1 Is Associated with Plant Height through the Gibberellin Pathway in Brassica rapa L.
by Wei Wang, Junyu Hu, Bing Fang, Xu Gao, Chunming Hao, Yizhuo Mu, Hui Feng, Gaoyang Qu and Yugang Wang
Horticulturae 2023, 9(2), 282; https://doi.org/10.3390/horticulturae9020282 - 19 Feb 2023
Cited by 1 | Viewed by 1888
Abstract
In crops such as Brassica rapa, the agronomic trait plant height affects the leaf light absorption rate, benefits substance accumulation, and increases production by increasing the biological yield of the population. The mechanism of plant height was adequately studied in Brassica napus [...] Read more.
In crops such as Brassica rapa, the agronomic trait plant height affects the leaf light absorption rate, benefits substance accumulation, and increases production by increasing the biological yield of the population. The mechanism of plant height was adequately studied in Brassica napus and Arabidopsis, while Brassica rapa had been rarely reported. Herein, we studied a B. rapa dwarf mutant Brcd1YS. Compared with its wild-type, Yellow sarson, Brcd1YS showed shorter hypocotyls and slow growth, with inhibited root elongation and reduced numbers of lateral roots. Chlorophyll content determination and pollen viability detection indicated that the mutant’s chlorophyll content was higher than that of the wild-type; however, its pollen was inactive. Cytological identification showed that the number of cells in Brcd1YS leaves was significantly reduced and were arranged irregularly compared with those of the wild-type. Bulked Segregant RNA sequencing combined with conventional linkage mapped the dwarf mutation Brcd1YS to Chromosome A06, at position 21,621,766 to 24,683,923 bp. Application of exogenous gibberellic acid (GA) partially rescued the dwarf phenotype of Brcd1YS. GA-related genes BraA06g034110.3C and BraA06g033010.3C were identified as the most promising candidate genes. These results make a valuable contribution to our understanding of the mechanism of plant height determination in B. rapa, paving the way for further breeding of dwarf B. rapa. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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9 pages, 5807 KiB  
Article
Analysis of the Postharvest Storage Characteristics of Two New Pear Cultivars ‘Shannongsu’ and ‘Xincixiang’
by Susu Zhang, Sumin Qi, Bin Li, Jing Zhang, Can Cui, Rui Zhang, Zhiquan Mao, Nan Wang, Xuesen Chen and Zongying Zhang
Horticulturae 2023, 9(2), 281; https://doi.org/10.3390/horticulturae9020281 - 19 Feb 2023
Viewed by 1227
Abstract
‘Shannongsu’ and ‘Xincixiang’ were two new late-ripening pear cultivars with high quality, that were bred by our team. In order to clear the postharvest storage characteristics, mature pears were collected and stored at room temperature. Several fruit characteristics were evaluated over time, such [...] Read more.
‘Shannongsu’ and ‘Xincixiang’ were two new late-ripening pear cultivars with high quality, that were bred by our team. In order to clear the postharvest storage characteristics, mature pears were collected and stored at room temperature. Several fruit characteristics were evaluated over time, such as firmness, ethylene release rate, content of aroma components, softening-related enzyme activity, and gene expression. Both ‘Shannongsu’ and ‘Xincixiang’ were crisp and juicy stored after 60 d at room temperature, which exhibited excellent storage characteristics. The storability may be comprehensive result of low levels of ethylene production, aroma synthesis, softening-related activities, and gene expression. The research cleared the storage characteristics of ‘Shannongsu’ and ‘Xincixiang’ at room temperature for the first time, which will provide scientific theoretical guidance for fruit production and marketing. Full article
(This article belongs to the Special Issue Postharvest Handling of Fruits and Vegetables)
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11 pages, 1621 KiB  
Article
Seed Longevity Potential Predicted by Radicle Emergence (RE) Vigor Test in Watermelon Seed Cultivars
by Erkan Eren, Sıtkı Ermis, Guleda Oktem and Ibrahim Demir
Horticulturae 2023, 9(2), 280; https://doi.org/10.3390/horticulturae9020280 - 19 Feb 2023
Cited by 3 | Viewed by 2052
Abstract
The study was conducted to test whether radicle emergence (RE) would correlate with the storage potential of ten seed lots of watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) hybrid cultivars (>98% normal germination). The RE test was performed by frequent counting radicle [...] Read more.
The study was conducted to test whether radicle emergence (RE) would correlate with the storage potential of ten seed lots of watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) hybrid cultivars (>98% normal germination). The RE test was performed by frequent counting radicle emergence (2 mm) percentage between 34 h and 60 h after germination was set up at 25 °C in the dark. Seed longevity was hermetically determined by artificial storage of seeds (air and waterproof) at 17 ± 0.3% of seed moisture and at 35 ± 2 °C over 63 days. Twelve seed samples were taken out during aging, and seed survival curves were constructed based on normal germination percentages conducted at 25 °C for seven days in the dark. The seed longevity criterion was P50 (time for the germination to fall to 50%), which was determined through probit analysis by using survival curves. Correlation analysis showed that RE counts at 42 h during germination were highly correlated (p < 0.01) with initial seed quality, Ki (r = 0.7538), and the half-viability period, P50 (r = 0.7936). Pre-storage normal germination percentages of seed lots were not related to longevity. Results showed that the RE vigor test has the potential to predict longevity in highly germinating hybrid watermelon seed lots. Full article
(This article belongs to the Collection Seed Dormancy and Germination of Horticultural Plants)
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12 pages, 2392 KiB  
Article
Quantification and Prediction with Near Infrared Spectroscopy of Carbohydrates throughout Apple Fruit Development
by James E. Larson, Penelope Perkins-Veazie, Guoying Ma and Thomas M. Kon
Horticulturae 2023, 9(2), 279; https://doi.org/10.3390/horticulturae9020279 - 18 Feb 2023
Cited by 5 | Viewed by 2325
Abstract
Carbohydrates play a key role in apple fruit growth and development. Carbohydrates are needed for cell division/expansion, regulate fruitlet abscission, and influence fruit maturation and quality. Current methods to quantify fruit carbohydrates are labor intensive and expensive. We quantified carbohydrates throughout a growing [...] Read more.
Carbohydrates play a key role in apple fruit growth and development. Carbohydrates are needed for cell division/expansion, regulate fruitlet abscission, and influence fruit maturation and quality. Current methods to quantify fruit carbohydrates are labor intensive and expensive. We quantified carbohydrates throughout a growing season in two cultivars and evaluated the use of near infrared spectroscopy (NIR) to predict apple carbohydrate content throughout changes in fruit development. Carbohydrates were quantified with high performance liquid chromatography (HPLC) at five timepoints between early fruitlet growth and harvest in ‘Gala’ and ‘Red Delicious’ apples. NIR spectra was collected for freeze-dried fruit samples using a benchtop near infrared spectrometer. Sorbitol was the major carbohydrate early in the growing season (~40% of total carbohydrates). However, the relative contribution of sorbitol to total carbohydrates rapidly decreased by 59 days after full bloom (<10%). The proportion of fructose to total carbohydrates increased throughout fruit development (40–50%). Three distinct periods of fruit development, early, mid-season, and late, were found over all sampling dates using principal component analysis. The first (PC1) and second (PC2) principal components accounted for 90% of the variation in the data, samples separated among sampling date along PC1. Partial least squares regression was used to build the models by calibrating carbohydrates quantified with HPLC and measured reflectance spectra. The NIR models reliably predicted the content of fructose, glucose, sorbitol, sucrose, starch, and total soluble sugars for both ‘Gala’ and ‘Red Delicious’; r2 ranged from 0.60 to 0.96. These results show that NIR can accurately estimate carbohydrates throughout the growing season and offers an efficient alternative to liquid or gas chromatography. Full article
(This article belongs to the Special Issue Research Advances in Horticultural Crop Physiology and Stress)
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12 pages, 1508 KiB  
Article
Immobilization of Pb in Contaminated Soils with the Combination Use of Diammonium Phosphate with Organic and Inorganic Amendments
by Simona M. Popescu, Valtcho D. Zheljazkov, Tess Astatkie, Marian Burducea and Walter C. Termeer
Horticulturae 2023, 9(2), 278; https://doi.org/10.3390/horticulturae9020278 - 18 Feb 2023
Cited by 1 | Viewed by 1359
Abstract
The intensive use of lead (Pb)-based insecticides (lead arsenate, PbHAsO4) has led to Pb accumulation in agricultural soil, endangering human health through the possibility of transferring it to the food chain. The aim of this study was to evaluate the potential [...] Read more.
The intensive use of lead (Pb)-based insecticides (lead arsenate, PbHAsO4) has led to Pb accumulation in agricultural soil, endangering human health through the possibility of transferring it to the food chain. The aim of this study was to evaluate the potential for the immobilization of Pb in the soil by applying organic (sludge, biocompost, yard compost, and peat) and inorganic (bonemeal, zeolite, lime, and wood ash) amendments, in combination with diammonium phosphate (DAP) in a greenhouse experiment. Two amendment rates were used: low and high, and three rates of DAP: 0 (zero), low (0.25 g of DAP/kg soil), and high (1.25 g DAP/kg soil). The results showed that the dry yield of carrot (Daucus carota susp. sativus) was the highest for the organic amendments in combination with the low rate of DAP. The high rate of inorganic amendments also increased the yield. Applications of inorganic bonemeal, inorganic lime, and inorganic wood ash yielded the lowest Pb tissue concentration (TC), and organic peat had the highest Pb TC. Inorganic bonemeal combined with DAP most effectively immobilized Pb in soil. Full article
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16 pages, 3370 KiB  
Article
Thidiazuron Induced In Vitro Plant Regeneration, Phenolic Contents, Antioxidant Potential, GC-MS Profiles and Nuclear Genome Stability of Plectranthus amboinicus (Lour.) Spreng
by Mohammad Faisal, Ahmed A. Qahtan and Abdulrahman A. Alatar
Horticulturae 2023, 9(2), 277; https://doi.org/10.3390/horticulturae9020277 - 18 Feb 2023
Cited by 5 | Viewed by 1734
Abstract
Plectranthus amboinicus (Lour.) Spreng is a perennial plant from the mint family with aromatic, succulent leaves and several health benefits. Multiple shoot regeneration was accomplished in vitro using nodal segments (NS) explants of P. amboinicus pretreated with 0, 0.5, 5, 25, 50, and [...] Read more.
Plectranthus amboinicus (Lour.) Spreng is a perennial plant from the mint family with aromatic, succulent leaves and several health benefits. Multiple shoot regeneration was accomplished in vitro using nodal segments (NS) explants of P. amboinicus pretreated with 0, 0.5, 5, 25, 50, and 100 μM thidiazuron (TDZ) for 4 h, then transferred to a growth regulator-free media. After 8 weeks of growth, NS explants pre-treated with 25 μM TDZ for 4 h and then transferred to TDZ-free Murashige and Skoog (MS) media produced the greatest number of shoots (27.3 per NS) with the longest average shoot length (4.9 mm) in 97.2% of cultures. On the same medium, regeneration of roots in most of the P. amboinicus shoots occurred spontaneously. The in vitro-regenerated P. amboinicus plantlets were adequately hardened off and adapted to the ex-vitro environment with a 90% survival rate. Total phenolic, tannin, and flavonoid contents, as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging/antioxidant activity, were significantly higher in in vitro-regenerated plants than in ex vitro-plants. Flow cytometry (FCM) analysis validated the nuclear genome stability of the in vitro generated plants, which assessed their nuclear DNA content and found it to be comparable in genome size to that of the field-grown plants. The study found a quick and efficient method for in vitro multiplication of P. amboinicus which can aid to increased availability and accessibility of this plant species for various purposes. The genetic and phytochemical analysis of the in vitro propagated plants can also provide valuable insight into the plant’s properties and potential applications, which can further assist in its preservation and sustainable usage. Full article
(This article belongs to the Special Issue In Vitro Technology and Micropropagated Plants)
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12 pages, 1748 KiB  
Article
Mycorrhization Enhances Vegetative Growth, Leaf Gas Exchange, and Root Development of Micropropagated Philodendron bipinnatifidum Schott ex Endl. Plantlets during Acclimatization
by Yaser Hassan Dewir, Muhammad M. Habib, AbdulAziz A. AlQarawi, Thobayet S. Alshahrani, Ahmed Ali Alaizari, Jahangir A. Malik, Mona S. Alwahibi and Hosakatte Niranjana Murthy
Horticulturae 2023, 9(2), 276; https://doi.org/10.3390/horticulturae9020276 - 17 Feb 2023
Cited by 1 | Viewed by 1968
Abstract
Philodendron bipinnatifidum Schott ex Endl. is a popular ornamental plant that is normally propagated by tissue culture methods. However, the growth and acclimatization of micropropagated plants are tarrying processes. Therefore, in the present study we examined the effect of arbuscular mycorrhizal fungi (AMF) [...] Read more.
Philodendron bipinnatifidum Schott ex Endl. is a popular ornamental plant that is normally propagated by tissue culture methods. However, the growth and acclimatization of micropropagated plants are tarrying processes. Therefore, in the present study we examined the effect of arbuscular mycorrhizal fungi (AMF) Gigaspora albida and G. marginata on the success in the establishment, growth, and development of P. bipinnatifidum plantlets during the acclimatization phase. AMF plants had significantly more leaves (10.67 per plant), leaf area (75.63 cm2), plant height (14.17 cm), shoot fresh weight (3.30 g) and shoot dry weight (0.31 g), according to an analysis of growth characteristics. In comparison, non-AMF plants had lower values for these metrics. In addition, AMF plants had significantly longer main roots (23 cm), total length roots per plantlet (485.73 cm), average root diameter (4.58 mm) per plantlet, number of root tips (236) per plant, total root surface area (697.76 cm2), total root volume (79.98 cm3), roots fresh weight (1.51 g), roots dry weight (0.16 g) than non-AMF plants. AMF-treated plants showed better performance in leaf gas exchange, chlorophyll, and carotenoid content. These results emphasize the need for mycorrhization of micropropagated plants to promote vegetative growth, especially during the acclimatization stage. Full article
(This article belongs to the Special Issue Seed Germination and Micropropagation of Ornamental Plants)
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16 pages, 3165 KiB  
Article
Stepwise Optimization of the RT-qPCR Protocol and the Evaluation of Housekeeping Genes in Pears (Pyrus bretschneideri) under Various Hormone Treatments and Stresses
by Peng Zhou, Linlin Huang, Yingtao Wang, Xiao Li, Xinxin Feng and Liulin Li
Horticulturae 2023, 9(2), 275; https://doi.org/10.3390/horticulturae9020275 - 17 Feb 2023
Cited by 3 | Viewed by 1692
Abstract
Real-time quantitative PCR (RT-qPCR) has become a widely used method for exploring plant gene expression level. The method requires using some stably expressed genes as a reference to accurately normalize the RT-qPCR data. However, under various stresses and hormone treatments, the levels of [...] Read more.
Real-time quantitative PCR (RT-qPCR) has become a widely used method for exploring plant gene expression level. The method requires using some stably expressed genes as a reference to accurately normalize the RT-qPCR data. However, under various stresses and hormone treatments, the levels of most reference genes vary. Environmental variations also influence their expression levels. The lack of validated, stably expressed reference genes can mislead the study of gene function in pears. “Huangguan” pears have recently become the focus of research on stress resistance mechanisms, such as high resistance. Therefore, the aim of this study was to select the optimal reference genes in Huangguan pears, and we analyzed the expression of the genes EF1α, ACT, SKD1, YLS8, UBQ, GAPDH, TUB, and WDP in a series of pear leaf sets under various stresses and hormone treatments. Using different statistical algorithms, we found that under various treatments, the WDP gene had more stable expression, ACT was the most stable under MeJA treatment, YLS8 was the most valuable reference gene under ABA hormone and heat stress conditions, and GAPDH showed worst results compared to other housekeeping genes, except under heat stress. These results will supply valuable and updated information for the selection of housekeeping genes in pears under biotic and abiotic stresses in the future. Full article
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15 pages, 2475 KiB  
Article
Enhancement of Antioxidant Potential, Phytochemicals, Nutritional Properties, and Growth of Siphonochilus aethiopicus (Schweinf.) B.L.Burtt with Different Dosages of Compost Tea
by Timothy Ivan Jasson, Muhali O. Jimoh, Christiaan W. Daniels, Felix Nchu and Charles P. Laubscher
Horticulturae 2023, 9(2), 274; https://doi.org/10.3390/horticulturae9020274 - 17 Feb 2023
Cited by 3 | Viewed by 1712
Abstract
The wild population of Siphonochilus aethiopicus (Zingiberaceae) is being eroded due to several pharmacological benefits and the hidden economy credited to its ethnobotanical uses in Southern Africa. This has called for the adoption of sustainable ways of cultivating the species without compromising its [...] Read more.
The wild population of Siphonochilus aethiopicus (Zingiberaceae) is being eroded due to several pharmacological benefits and the hidden economy credited to its ethnobotanical uses in Southern Africa. This has called for the adoption of sustainable ways of cultivating the species without compromising its bioactive constituents. In this study, compost tea was brewed and applied at different dosages to potted S. aethiopicus to enhance its growth quality, phytochemical content, and elemental compositions. Treatments comprised 0.25, 0.50, 0.75 and 1.00 (vv) graded concentrations of compost tea, while water and undiluted compost tea were the control treatments. Results showed that dosages of compost tea had no significant effect on chlorophyl content or fresh and dry weights of rhizomes of S. aethiopicus. The longest leaves were recorded in plants irrigated with water only, while the shortest leaves were recorded in plants irrigated by 50% compost tea. A similar trend was observed in leaf width, except that equivalent values were recorded in all compost tea treatments while plants irrigated with undiluted compost tea were tallest. The highest and lowest flavanols were respectively recorded in 0.50 and 0.25 compost tea-treated plant samples, while undiluted compost tea yielded the highest flavonol and phenolic acids. The highest antioxidant contents were produced by the 0.25 compost tea-treated samples in the ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), FRAP (Ferric Reducing Antioxidant Power) and ORAC (Oxygen Radical Antioxidant Capacity) assays, while the lowest were observed in plants irrigated with water only, although all compost tea-treated plants had equivalent effects on the ORAC content. The highest N, P, K, and Mn contents were produced in the 0.25-treated samples, while the minerals were least accumulated in samples treated with water only. All treatments had equivalent effects on Ca, Zn, and B yield, whereas the highest and equivalent accumulations of Mg and Na were recorded in the control treatments. Iron (Fe) and Cu were most influenced significantly by water whereas P, Ca and Zn tissue concentration was not significantly influenced by treatments. These results indicate that compost tea can optimize growth, mineral accumulation, phytochemicals, and antioxidants in S. aethiopicus. This approach serves as a greener and sustainable way of conserving overexploited indigenous medicinal plants such as S. aethiopicus to mitigate overexploitation of its wild relatives and preserve its genome from imminent extinction. Full article
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18 pages, 3864 KiB  
Article
In Vitro Propagation of Three Populations of the Endangered, Greek Endemic Cerastium candidissimum and Short-Term Storability of Alginate-Encapsulated Shoot Explants for Exploitation and Conservation
by Konstantinos Bertsouklis and Stella Tsopela
Horticulturae 2023, 9(2), 273; https://doi.org/10.3390/horticulturae9020273 - 17 Feb 2023
Cited by 2 | Viewed by 1812
Abstract
Cerastium candidissimum Correns is an endangered species. Nevertheless, its ornamental characteristics make it an ideal candidate for commercial use as a new ornamental and landscape plant. As there are no references to the in vitro propagation of this species, the present research aims [...] Read more.
Cerastium candidissimum Correns is an endangered species. Nevertheless, its ornamental characteristics make it an ideal candidate for commercial use as a new ornamental and landscape plant. As there are no references to the in vitro propagation of this species, the present research aims to comparatively investigate the potential that in vitro propagation may have of three different populations of the plant, from Mounts Parnassos (PS), Parnitha (PR), and Hymettus (HM), respectively. The establishment of the initial cultures took place by cotyledonary- and stem-node explants, excised from in vitro grown seedlings, on Murashige and Skoog (MS) media, without hormone (Hf), or with 0.5 mg L−1 6-benzyladenine (BA). The shooting percentage was higher in the case of the PS population (97.6%). It was also higher for stem-node explants (93.9%). The multiplication phase took place on Hf MS, or on MS containing BA (0.5 and 1.0 mg L−1), with or without 0.1 mg L−1 1-Naphthaleneacetic acid. The higher shoot production was observed in the PS and PR populations (88.0% and 76.9% shooting, with 3.1 and 2.7 shoots/explant, respectively). Micro-shoots rooted at high percentages on half-strength MS (80.0–100.0%). Successful acclimatisation (95.0%) was established on peat: perlite (1:1 v/v). Moreover, an efficient alginate-encapsulation procedure was developed from PS stem-node explants, using a 3.0% w/v sodium alginate and 14.7 g L−1 calcium chloride solution. Alginate beads exhibited a higher shoot proliferation (3.8 shoots) after 60 days of storage at 4.0 °C and a 50-day growth on Hf MS than non-encapsulated in vitro node-explants did. The presented protocol of in vitro propagation of C. candidissimum could facilitate the exploitation of the species by the floricultural industry and contribute to conservation strategies. Full article
(This article belongs to the Special Issue In Vitro Propagation and Biotechnology of Horticultural Plants)
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18 pages, 9621 KiB  
Article
Characterization of the Passion Fruit (Passiflora edulis Sim) bHLH Family in Fruit Development and Abiotic Stress and Functional Analysis of PebHLH56 in Cold Stress
by Yi Xu, Weidong Zhou, Funing Ma, Dongmei Huang, Wenting Xing, Bin Wu, Peiguang Sun, Di Chen, Binqiang Xu and Shun Song
Horticulturae 2023, 9(2), 272; https://doi.org/10.3390/horticulturae9020272 - 17 Feb 2023
Cited by 7 | Viewed by 2275
Abstract
Abiotic stress is the focus of research on passion fruit characters because of its damage to the industry. Basic helix-loop-helix (bHLH) is one of the Transcription factors (TFs) which can act in an anti-abiotic stress role through diverse biological processes. However, no systemic [...] Read more.
Abiotic stress is the focus of research on passion fruit characters because of its damage to the industry. Basic helix-loop-helix (bHLH) is one of the Transcription factors (TFs) which can act in an anti-abiotic stress role through diverse biological processes. However, no systemic analysis of the passion fruit bHLH (PebHLH) family was reported. In this study, 117 PebHLH members were identified from the genome of passion fruit, related to plant stress resistance and development by prediction of protein interaction. Furthermore, the transcriptome sequencing results showed that the PebHLHs responded to different abiotic stresses. At different ripening stages of passion fruit, the expression level of most PebHLHs in the immature stage (T1) was higher than that in the mature stage (T2 and T3). Eight PebHLHs with differentially expressed under different stress treatments and different ripening stages were selected and verified by qRT-PCR. In this research, the expression of one member, PebHLH56, was induced under cold stress. Further, the promoter of PebHLH56 was fused to β-Galactosidase (GUS) to generate the expression vector that was transformed into Arabidopsis. It showed that PebHLH56 could significantly respond to cold stress. This study provided new insights into the regulatory functions of PebHLH genes during fruit maturity stages and abiotic stress, thereby improving the understanding of the characteristics and evolution of the PebHLH gene family. Full article
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21 pages, 4043 KiB  
Article
Large-Scale In Vitro Propagation and Ex Vitro Adaptation of the Endangered Medicinal Plant Eryngium maritimum L.
by Ieva Mežaka, Dace Kļaviņa, Laura Kaļāne and Arta Kronberga
Horticulturae 2023, 9(2), 271; https://doi.org/10.3390/horticulturae9020271 - 17 Feb 2023
Cited by 5 | Viewed by 2227
Abstract
The endangered medicinal plant Eryngium maritimum L. faces significant natural and anthropogenic threats. Therefore, in vitro propagation is recommended for both conservation and commercial purposes. The aim of the study was to develop a series of protocols for seed disinfection, in vitro multiplication [...] Read more.
The endangered medicinal plant Eryngium maritimum L. faces significant natural and anthropogenic threats. Therefore, in vitro propagation is recommended for both conservation and commercial purposes. The aim of the study was to develop a series of protocols for seed disinfection, in vitro multiplication and rooting, and ex vitro and field adaptation. For explant disinfection, the length and temperature of three consecutive disinfectants were investigated. Macrosalt modifications of MS medium and plant growth regulator addition to media effect on axillary bud propagation rate and rooting was studied. Survival and leaf growth during ex vitro and field adaptation in response to potting media, pot cell diameter, and light spectrum were tested. Seeds treated with diluted detergent at 40 °C for 180 min, followed by 0.01% KMnO4 for 3 h and commercial bleach for 11 min, achieved a lower rate of contamination and high germination rate. Axillary bud proliferation and rooting were enhanced by reducing nitrogen content in media and adding plant growth regulators. Potting media and pot size affect survival and growth ex vitro. Timely transplantation to field conditions before overwintering increases plantlet survival. In the present work, a suitable foundation is laid to scaleup the production of E. maritimum by micropropagation. Full article
(This article belongs to the Special Issue A New Decade in the Propagation of Horticultural and Medicinal Plants)
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13 pages, 4064 KiB  
Article
Red-TE Homozygous Alleles of MdMYB10 Confer Full-Red Apple Fruit Skin in a High-Temperature Region
by Meili Wang, Yarong Wang, Tiyu Ding, Zhenli Yan, Zhe Zhou, Cuiying Li, Jia-Long Yao and Hengtao Zhang
Horticulturae 2023, 9(2), 270; https://doi.org/10.3390/horticulturae9020270 - 17 Feb 2023
Cited by 1 | Viewed by 2133
Abstract
Apple is a major fruit crop grown worldwide and provides humans with an essential diet and health benefits. One of the health benefits is related to the accumulation of fruit anthocyanin, which also provides fruit with an attractive red colour. It is known [...] Read more.
Apple is a major fruit crop grown worldwide and provides humans with an essential diet and health benefits. One of the health benefits is related to the accumulation of fruit anthocyanin, which also provides fruit with an attractive red colour. It is known that an MdMYB10 allele containing a transposable element (TE) insertion in its promoter (termed Red-TE allele) underlies anthocyanin accumulation and red colouration in the fruit skin of cultivated apples. However, the distribution of this Red-TE allele in wider Malus germplasm accessions is not clear. In this study, we showed that MdMYB10 RNA in fruit skin was specifically expressed from the Red-TE allele by using allele-specific expression analysis of transcriptome data. Apple cultivars and hybrids with homozygous Red-TE alleles showed stronger red colour than those with heterozygous alleles after analysing 65 cultivars and 337 hybrids. Furthermore, both hetero- and homozygous plants growing in the same high-temperature conditions had different colourations. However, the Red-TE allele was not detected in 16 wild apple accessions showing red skin, indicating that the red skin colour of these wild apples was not conferred by the Red-TE allele. These findings provide guidance for selecting cultivars able to develop consistent red colouration under high growth temperature conditions and open the opportunity for identifying novel genetic variants underpinning fruit red colouration in wild apple species. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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12 pages, 1685 KiB  
Article
Evaluation of SPAD Index for Estimating Nitrogen and Magnesium Contents in Three Blueberry Varieties (Vaccinium corymbosum L.) on the Andean Tropics
by Elberth Hernando Pinzón-Sandoval, Helber Enrique Balaguera-López and Pedro José Almanza-Merchán
Horticulturae 2023, 9(2), 269; https://doi.org/10.3390/horticulturae9020269 - 17 Feb 2023
Cited by 3 | Viewed by 1889
Abstract
In the Ericaceae family, blueberries are the most commercially important species. Estimating the nutritional and physiological status of plants is a common practice carried out by producers. However, conventional methods are destructive, costly and time consuming. In recent years, methodologies such as measurements [...] Read more.
In the Ericaceae family, blueberries are the most commercially important species. Estimating the nutritional and physiological status of plants is a common practice carried out by producers. However, conventional methods are destructive, costly and time consuming. In recent years, methodologies such as measurements with the SPAD chlorophyll index have become available, which has proven to be an easy, fast and non-destructive method for estimating chlorophyll, N and Mg contents in the field. Therefore, this research aimed to estimate variations in SPAD readings between varieties and to determine whether Chlorophyll Index (SPAD) values are associated with Nitrogen and Magnesium contents in blueberry plants (Vaccinium corymbosum L.) from the varieties ‘Biloxi’, ‘Legacy’ and ‘Victoria’ in the vegetative phase under the conditions in the municipality of Paipa-Boyacá (Colombia). The varieties presented statistical differences in the SPAD index values, with a linear correlation between the SPAD index and the contents of N and Mg with a coefficient of determination (R2) greater than 0.8 in the three varieties. This result confirmed the usefulness and importance of using SPAD as a nutrition management tool in the evaluated varieties based on the SPAD readings, with a subsequent relationship with the threshold values of the foliar N and Magnesium status under field conditions. Full article
(This article belongs to the Section Fruit Production Systems)
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21 pages, 2721 KiB  
Article
Regulatory Effect of Exogenous γ-Aminobutyric Acid on Respiratory Rate through the γ-Aminobutyric Acid Shunt in Malus baccata (L.) Borkh. Roots under Suboptimal Low Root-Zone Temperature
by Xiaochen Lu, Ping Dai, Huaiyu Ma and Deguo Lyu
Horticulturae 2023, 9(2), 268; https://doi.org/10.3390/horticulturae9020268 - 16 Feb 2023
Cited by 4 | Viewed by 1416
Abstract
Malus baccata (L.) Borkh. is one of the most widely used rootstocks in the apple-producing region of Northern China. However, in the early growing season, apple roots are often subjected to suboptimal low root-zone temperatures. The regulatory effects of exogenous γ-aminobutyric acid (GABA) [...] Read more.
Malus baccata (L.) Borkh. is one of the most widely used rootstocks in the apple-producing region of Northern China. However, in the early growing season, apple roots are often subjected to suboptimal low root-zone temperatures. The regulatory effects of exogenous γ-aminobutyric acid (GABA) on both the γ-aminobutyric acid shunt (GABA shunt) and the respiratory activity of roots under suboptimal low root-zone temperatures remain unknown. To explore the physiological basis for GABA alleviation of low-temperature stress in M. baccata Borkh. roots, the following treatments were examined: suboptimal low root-zone temperature (potted parts of the seedlings were maintained at 5 ± 0.5 °C; L); suboptimal low root-zone temperature + GABA (LG); and suboptimal low root-zone temperature + vigabatrin (VGB; LV), which is a specific active inhibitor of γ-aminobutyric acid transaminase (GABA-T). Each treatment was matched with a control (18 °C/8 °C day/night; CK) for comparison. Our results showed that the L treatment reduced the root vitality, increased malondialdehyde (MDA) content, promoted the accumulation of GABA, activated the GABA shunt, and inhibited the total root respiration rate (VTotal) by decreasing the respiratory rates of Embden–Meyerhof pathway (VEMP) and tricarboxylic acid cycle (VTCAC). The LG treatment significantly increased the content of endogenous GABA, accelerated the metabolism of the GABA shunt, enhanced root respiratory activity by increasing VTotal, VEMP, VTCAC, and increased the cytochrome pathway respiratory rate (VCP), thus alleviating the damage of low root-zone temperature stress. Meanwhile, contrasting results were observed in the LV treatment. These findings revealed that exogenous GABA improved the tolerance of apple rootstocks to suboptimal low temperatures in early spring by regulating the GABA shunt and root respiratory activity. Full article
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13 pages, 2370 KiB  
Article
Application of a Generic Participatory Decision Support System for Irrigation Management for the Case of a Wine Grapevine at Epirus, Northwest Greece
by Ioannis L. Tsirogiannis, Nikolaos Malamos and Penelope Baltzoi
Horticulturae 2023, 9(2), 267; https://doi.org/10.3390/horticulturae9020267 - 16 Feb 2023
Cited by 3 | Viewed by 1420
Abstract
In southern Europe, irrigation is the major water user and thus, development of operational tools that support decisions aiming to improve irrigation management, is of great importance. In this study, a web-based participatory decision support system for irrigation management (DSS), based on the [...] Read more.
In southern Europe, irrigation is the major water user and thus, development of operational tools that support decisions aiming to improve irrigation management, is of great importance. In this study, a web-based participatory decision support system for irrigation management (DSS), based on the principles of UN FAO’s paper 56, without requirement for any special monitoring hardware to be installed in each field, is evaluated for the case of a commercial wine grapevine (Vitis vinifera ‘Vertzami’) located at Epirus (northwest Greece), for two successive years (2021 and 2022). The soil moisture time series that were generated by the DSS’s model were compared to those measured by soil moisture sensors. The Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) ranged between 2.98–3.22% and 3.63–4.06%, respectively, under various irrigation practices and goals. Irrigation resulted very high yields and Crop Water Productivity (WPC) was 20–44% improved when following the DSS’s recommendations. The results also confirm potential pitfalls of sensor-based soil moisture monitoring and rainfall estimations using mathematical models. Finally, the value of water meters as practical sensors, which could support efficient irrigation management, is underlined. In every case, mindful application of decision support systems that require minimum or no hardware to be installed in each field, could extensively support growers and agronomic consultants to test, document and disseminate good practices and calculate environmental indices. Full article
(This article belongs to the Section Fruit Production Systems)
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21 pages, 99887 KiB  
Article
UAV Photogrammetry-Based Apple Orchard Blossom Density Estimation and Mapping
by Wenan Yuan, Weiyun Hua, Paul Heinz Heinemann and Long He
Horticulturae 2023, 9(2), 266; https://doi.org/10.3390/horticulturae9020266 - 16 Feb 2023
Cited by 4 | Viewed by 2286
Abstract
Thinning is an important routine for apple growers to manage crop load and improve fruit quality, which can be accomplished through manual, chemical, or mechanical manipulation of flowers and fruitlets. Traditionally, blossom thinning relies on human experts’ visual evaluation of the flower load, [...] Read more.
Thinning is an important routine for apple growers to manage crop load and improve fruit quality, which can be accomplished through manual, chemical, or mechanical manipulation of flowers and fruitlets. Traditionally, blossom thinning relies on human experts’ visual evaluation of the flower load, a leading indicator of crop load, which can be imprecise and prone to errors. This study aimed to develop an apple blossom density mapping algorithm utilizing point clouds reconstructed through unmanned aerial vehicle (UAV)-based red-green-blue (RGB) imagery and photogrammetry. The algorithm was based on grid average downsampling and white color thresholding, and it was able to generate top-view blossom density maps of user-defined tree height regions. A preliminary field experiment was carried out to evaluate the algorithm’s accuracy using manual blossom counts of apple tree row sections as ground truths, and a coefficient of determination (R2) of 0.85, a root mean square error (RMSE) of 1307, and a normalized RMSE (NRMSE) of 9.02% were achieved. The algorithm was utilized to monitor the blooming of the apple tree rows and was demonstrated to effectively show blossom density variations between different tree rows and dates. The study results suggested the potential of UAVs as a convenient tool to assist precise blossom thinning in apple orchards, while future research should further investigate the reliability of photogrammetry techniques under different image qualities and flight settings as well as the influence of blossom distribution on algorithm accuracy. Full article
(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)
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11 pages, 1156 KiB  
Review
Genetic Components of Self-Incompatibility in Brassica Vegetables
by Fenghua Wang, Yufei Li, Guangyuan Li and Shuangchen Chen
Horticulturae 2023, 9(2), 265; https://doi.org/10.3390/horticulturae9020265 - 16 Feb 2023
Cited by 3 | Viewed by 2129
Abstract
Brassica vegetables are very important to human beings. Self-incompatibility (SI) is a common phenomenon in Brassica. Breeding by SI lines is an important way to utilize heterosis of Brassica vegetables. It is believed that the SI inheritance in Brassica species is controlled by [...] Read more.
Brassica vegetables are very important to human beings. Self-incompatibility (SI) is a common phenomenon in Brassica. Breeding by SI lines is an important way to utilize heterosis of Brassica vegetables. It is believed that the SI inheritance in Brassica species is controlled by three linkage genes on the S-locus, including SRK (S-locus receptor kinase), SCR (S-locus cystine-rich protein)/SP11 (S-locus protein 11), and SLG (S-locus glycoprotein). SRK is the female determinant and SCR/SP11 is the pollen S gene. The expression of SLG is necessary for SRK, and it enhances the SRK-mediated SI reaction. In addition to these three S-locus genes, some other functional molecules also have significant regulatory effects on SI, such as ARC1 (arm repeat containing 1), MLPK (M-locus protein kinase), Exo70A1 (exocyst compounds), THLl/THL2 (thioredoxin H-like), MOD (aquaporin), SLR (S-locus-related glycoprotein), BPCI (pollen calcium-binding protein I), etc. SI is also associated with the dominant/recessive relationship between S alleles. Here, the genetic elements and molecular mechanisms of SI, mainly in Brassica vegetables, are reviewed. Full article
(This article belongs to the Collection Genetic Engineering and Quality Improvement in Vegetable Crops)
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11 pages, 1724 KiB  
Essay
Rapid and Efficient Regeneration of Rhododendron decorum from Flower Buds
by Hairong Wu, Qian Ao, Huie Li and Fenfang Long
Horticulturae 2023, 9(2), 264; https://doi.org/10.3390/horticulturae9020264 - 15 Feb 2023
Cited by 1 | Viewed by 1564
Abstract
Rhododendron decorum is a woody species with high ornamental and medical value. Herein, we introduce a novel in vitro regeneration method for R. decorum. We used flower buds to develop an efficient and rapid plant regeneration protocol. Sterile flower buds of R. [...] Read more.
Rhododendron decorum is a woody species with high ornamental and medical value. Herein, we introduce a novel in vitro regeneration method for R. decorum. We used flower buds to develop an efficient and rapid plant regeneration protocol. Sterile flower buds of R. decorum of a 2 cm size were used as explants to study the effects of the culture medium and plant growth regulators on the callus induction and adventitious shoot differentiation, proliferation, and rooting. According to the results, the optimal medium combination for callus induction was WPM + 1 mg/L TDZ + 0.2 mg/L NAA, and its induction rate reached 95.08%. The optimal medium combination for adventitious shoot differentiation from the callus was WPM + 0.5 mg/L TDZ + 0.1 mg/L NAA, and its differentiation rate reached 91.32%. The optimal medium combination for adventitious shoot proliferation was WPM + 2 mg/L ZT + 0.5 mg/L NAA, for which the proliferation rate reached 95.32% and the proliferation coefficient reached 9.45. The optimal medium combination for rooting from adventitious shoots was WPM + 0.1 mg/L NAA + 1 mg/L IBA, and its rooting rate reached 86.90%. The survival rates of the rooted regenerated plantlets exceeded 90% after acclimatization and transplantation. This regeneration system has the advantages of being simple and highly efficient, and it causes little damage to the shoots of the mother plants, laying a foundation for the plantlet propagation, genetic transformation, and new-variety breeding of R. decorum. Full article
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13 pages, 4163 KiB  
Article
Genetic Mapping of a Candidate Gene ClIS Controlling Intermittent Stripe Rind in Watermelon
by Yinping Wang, Shixiang Duan, Qishuai Kang, Dongming Liu, Sen Yang, Huanhuan Niu, Huayu Zhu, Shouru Sun, Jianbin Hu, Junling Dou and Luming Yang
Horticulturae 2023, 9(2), 263; https://doi.org/10.3390/horticulturae9020263 - 15 Feb 2023
Cited by 1 | Viewed by 2062
Abstract
Rind pattern is one of the most important appearance qualities of watermelon, and the mining of different genes controlling rind pattern can enrich the variety of consumer choices. In this study, a unique intermittent rind stripe was identified in the inbred watermelon line [...] Read more.
Rind pattern is one of the most important appearance qualities of watermelon, and the mining of different genes controlling rind pattern can enrich the variety of consumer choices. In this study, a unique intermittent rind stripe was identified in the inbred watermelon line WT20. The WT20 was crossed with a green stripe inbred line, WCZ, to construct F2 and BC1 segregating populations and to analyze the genetic characterization of watermelon stripe. Genetic analysis showed that the intermittent stripe was a qualitative trait and controlled by a single dominant gene, ClIS. Fine mapping based on linkage analysis showed that the ClIS gene was located on the 160 Kb regions between 25.92 Mb and 26.08 Mb on watermelon chromosome 6. Furthermore, another inbred watermelon line with intermittent stripe, FG, was re-sequenced and aligned on the region of 160 Kb. Interestingly, only two SNP variants (T/C, A/T) were present in both WT20 and FG inbred lines at the same time. The two SNPs are located in 25,961,768 bp (T/C) and 25,961,773 bp (A/T) of watermelon chromosome 6, which is located in the promoter region of Cla019202. We speculate that Cla019202 is the candidate gene of ClIS which controls the intermittent stripe in watermelon. In a previous study, the candidate gene ClGS was proved to control dark green stripe in watermelon. According to the verification of the two genes ClIS and ClGS in 75 watermelon germplasm resources, we further speculate that the ClGS gene may regulate the color of watermelon stripe, while the ClIS gene regulates the continuity of watermelon stripe. The study provides a good entry point for studying the formation of watermelon rind patterns, as well as providing foundation insights into the breeding of special appearance quality in watermelon. Full article
(This article belongs to the Special Issue Advance in Molecular Mechanism of Horticultural Crops - Pathogens)
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19 pages, 2128 KiB  
Article
Exogenous Application of Melatonin Alleviates Drought Stress in Ranunculus asiaticus by Improving Its Morphophysiological and Biochemical Attributes
by Eman Abdelhakim Eisa, Péter Honfi, Andrea Tilly-Mándy and Mayank Anand Gururani
Horticulturae 2023, 9(2), 262; https://doi.org/10.3390/horticulturae9020262 - 15 Feb 2023
Cited by 9 | Viewed by 1892
Abstract
Melatonin (MT) controls various physiological functions and enhances plant drought tolerance. This study aimed to evaluate the effect of exogenous MT on the morpho-physiological and biochemical attributes of Ranunculus asiaticus under normal and drought conditions. A completely randomized design was used with two [...] Read more.
Melatonin (MT) controls various physiological functions and enhances plant drought tolerance. This study aimed to evaluate the effect of exogenous MT on the morpho-physiological and biochemical attributes of Ranunculus asiaticus under normal and drought conditions. A completely randomized design was used with two factors, drought stress and MT concentration (0, 50, 100, and 200 μM), to assess the effect of foliar application of MT on R. asiaticus seedlings. The experiment was conducted with a total of two groups: the drought stress group and the control group. The foliar application of MT was carried out four times during the study period. The drought stress group exhibited considerably decreased shoot length by 26.0%, leaf number by 31.03%, leaf area by 62.2%, fresh and dry vegetative weights by 34.5% and 52.9%, respectively, total chlorophyll and carotenoid contents by 68.29% and 51.72%, respectively, and relative water content by 7.1%; early emergence of flower stalks was observed within 29 days; increased relative electrolyte leakage by 20.5% compared to well-watered plants. Conversely, the foliar application of MT notably increased growth parameters compared with their no-treatment counterparts. Foliar treatment with 200 µM MT resulted in the most significant growth response in R. asiaticus under normal and drought stress conditions. Moreover, under stressful conditions compared with no treatment, exogenously applied MT induced the appearance of flower buds 21 days early and increased relative water content by 6.4%, proline contents by 32%, and peroxidase activity by 58% while reducing electrolyte leakage by 14.3%. Regarding tolerance index percentages, higher peroxidase and proline contents indicated their suitability for use as markers for drought tolerance, supporting the effective role of exogenous MT in enhancing the adaptability of Ranunculus to drought stress. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
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13 pages, 3552 KiB  
Article
Evaluation of Pecan [Carya illinoinensis (Wangenh.) K. Koch] Cultivars for Possible Cultivation for Both Fruit and Truffle Production in the Puglia Region, Southeastern Italy
by Giuseppe Ferrara, Leonardo Lombardini, Andrea Mazzeo and Giovanni Luigi Bruno
Horticulturae 2023, 9(2), 261; https://doi.org/10.3390/horticulturae9020261 - 15 Feb 2023
Cited by 3 | Viewed by 2226
Abstract
Yield and different nut parameters were measured for two growing seasons on mature (28–29 years) trees of 11 pecan cultivars grown in an experimental orchard located in the Puglia Region, Southeastern Italy. ‘Shoshoni’ and ‘Shawnee’ pecan seedlings were inoculated with three truffle species [...] Read more.
Yield and different nut parameters were measured for two growing seasons on mature (28–29 years) trees of 11 pecan cultivars grown in an experimental orchard located in the Puglia Region, Southeastern Italy. ‘Shoshoni’ and ‘Shawnee’ pecan seedlings were inoculated with three truffle species (Tuber borchii—known as the ‘whitish truffle’, T. aestivum—called the ‘summer truffle’, and T. melanosporum—the common ‘Black truffle’) and investigated for six months. The level of ectomycorrhizal colonization was assessed 6 and 12 months after inoculation. Results indicated that ‘Wichita’, ‘Shoshoni’, and ‘Pawnee’ performed well in the pedoclimatic conditions of the area with a yield higher than 20 kg/tree and a kernel dry weight of ≅3 g. These preliminary yield results suggested that some pecan cultivars could deserve consideration for cultivation in the Puglia Region, whereas others with low yield and a stronger alternate bearing should not be considered. Plant height, number of leaves, chlorophyll content (expressed as a SPAD unit) and stem diameter partially indicated the increase in ecological fitness in truffles-inoculated plants. Successful mycorrhization indicated ‘Shoshoni’ and ‘Shawnee’ as suitable to establish ectomycorrhizal symbiosis with T. aestivum, T. borchii, and T. melanosporum cultivation under Puglia climatic conditions. The results also showed that the applied protocol was adequate to obtain healthy mycorrhized seedlings appropriate for commercialization and plantation for truffles production on pecan in the future. Full article
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16 pages, 2835 KiB  
Essay
RNA-Seq Based Transcriptomic Analysis of Bud Sport Skin Color in Grape Berries
by Wuwu Wen, Haimeng Fang, Lingqi Yue, Muhammad Khalil-Ur-Rehman, Yiqi Huang, Zhaoxuan Du, Guoshun Yang and Yanshuai Xu
Horticulturae 2023, 9(2), 260; https://doi.org/10.3390/horticulturae9020260 - 15 Feb 2023
Cited by 1 | Viewed by 1462
Abstract
The most common bud sport trait in grapevines is the change in color of grape berry skin, and the color of grapes is mainly developed by the composition and accumulation of anthocyanins. Many studies have shown that MYBA is a key gene regulates [...] Read more.
The most common bud sport trait in grapevines is the change in color of grape berry skin, and the color of grapes is mainly developed by the composition and accumulation of anthocyanins. Many studies have shown that MYBA is a key gene regulates the initiation of bud sport color and anthocyanin synthesis in grape peels. In the current study, we used berry skins of ‘Italia’, ‘Benitaka’, ‘Muscat of Alexandria’, ‘Flame Muscat’, ‘Rosario Bianco’, ‘Rosario Rosso’, and ‘Red Rosario’ at the véraison stage (10 weeks post-flowering and 11 weeks post-flowering) as research materials. The relative expressions of genes related to grape berry bud sport skin color were evaluated utilizing RNA-Seq technology. The results revealed that the expressions of the VvMYBA1/A2 gene in the three red grape varieties at the véraison stage were higher than in the three white grape varieties. The VvMYBA1/A2 gene is known to be associated with UFGT in the anthocyanin synthesis pathway. According to the results, VvMYBA1/A2 gene expression could also be associated with the expression of LDOX. In addition, a single gene (gene ID: Vitvi19g01871) displayed the highest expressions in all the samples at the véraison stage for the six varieties. The expression of this gene was much higher in the three green varieties compared to the three red ones. GO molecular function annotation identified it as a putative metallothionein-like protein with the ability to regulate the binding of copper ions to zinc ions and the role of maintaining the internal stable state of copper ions at the cellular level. High expression levels of this screened gene may play an important role in bud sport color of grape berry skin at the véraison stage. Full article
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