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Horticulturae, Volume 8, Issue 5 (May 2022) – 117 articles

Cover Story (view full-size image): Coffee producers are interested in understanding the dynamics of spatial and temporal variability in coffee. One of the most suitable ways to acquire this knowledge is to obtain yield data. Prior knowledge of high and low yield areas allows the producer to adopt localized management strategies, optimize inputs, and increase the productive efficiency of their areas. One of the ways to obtain yield data is using yield monitors embedded in harvesters. In coffee culture, there are few studies on this topic that aim to obtain high-density data and allow further studies regarding spatial and temporal variability. View this paper
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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
Viewed by 487
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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Review
Rhamnogalacturonan Endolyase Family 4 Enzymes: An Update on Their Importance in the Fruit Ripening Process
Horticulturae 2022, 8(5), 465; https://doi.org/10.3390/horticulturae8050465 - 21 May 2022
Viewed by 530
Abstract
Fruit ripening is a process that produces fruit with top sensory qualities that are ideal for consumption. For the plant, the final objective is seed dispersal. One of the fruit characteristics observed by consumers is texture, which is related to the ripening and [...] Read more.
Fruit ripening is a process that produces fruit with top sensory qualities that are ideal for consumption. For the plant, the final objective is seed dispersal. One of the fruit characteristics observed by consumers is texture, which is related to the ripening and softening of the fruit. Controlled and orchestrated events occur to regulate the expression of genes involved in disassembling and solubilizing the cell wall. Studies have shown that changes in pectins are closely related to the loss of firmness and fruit softening. For this reason, studying the mechanisms and enzymes that act on pectins could help to elucidate the molecular events that occur in the fruit. This paper provides a review of the enzyme rhamnogalacturonan endolyase (RGL; EC 4.2.2.23), which is responsible for cleavage of the pectin rhamnogalacturonan I (RGL-I) between rhamnose (Rha) and galacturonic acid (GalA) through the mechanism of β-elimination during fruit ripening. RGL promotes the loosening and weakening of the cell wall and exposes the backbone of the polysaccharide to the action of other enzymes. Investigations into RGL and its relationship with fruit ripening have reliably demonstrated that this enzyme has an important role in this process. Full article
(This article belongs to the Special Issue Cell Wall Composition and Extract)
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Article
Seed Maturity and Its In Vitro Initiation of Chilean Endemic Geophyte Alstroemeriapelegrina L.
Horticulturae 2022, 8(5), 464; https://doi.org/10.3390/horticulturae8050464 - 21 May 2022
Viewed by 536
Abstract
Alstroemeria pelegrina (A. pelegrina), a Chilean endemic, is considered vulnerable as its natural habitat is currently threatened. The decline in the reproductive capacity of the species due to anthropogenic impacts and climate change has made it imperative to address the problem [...] Read more.
Alstroemeria pelegrina (A. pelegrina), a Chilean endemic, is considered vulnerable as its natural habitat is currently threatened. The decline in the reproductive capacity of the species due to anthropogenic impacts and climate change has made it imperative to address the problem by developing large-scale propagation methods. The objective of this study was to establish protocols for breaking the dormancy and in vitro germination of A. pelegrina seeds to speed up the germination and seedling production processes. The research began with morphological observations of the reproductive process, followed by in vitro sowing. The results showed that the seeds reached full maturity in 51 days, and physiological maturity in 41 days, at which point the seeds could be harvested for in vitro germination. The mechanical scarification pretreatment improves the in vitro germination rate to 96% and the germination time to 7 days, showing that the species is characterized by physical seed dormancy. On the other hand, if the seed coat incisions are deeper than 0.5 mm, 30% of the potential plants are lost due to embryo damage. The study provides scientific evidence for the feasibility of large-scale in vitro propagation of the species and establishes an efficient method of seedling production. Full article
(This article belongs to the Special Issue Seed Dormancy and Germination of Horticultural Plants)
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Article
Effects of Bacillus cereus on Photosynthesis and Antioxidant Metabolism of Cucumber Seedlings under Salt Stress
Horticulturae 2022, 8(5), 463; https://doi.org/10.3390/horticulturae8050463 - 20 May 2022
Viewed by 586
Abstract
Soil salinization is the leading environmental factor that restricts crop growth. This study studied the effects of Bacillus cereus (B. cereus) on growth, photosynthesis, and antioxidant metabolism in salt stressed-cucumber seedlings. The results showed that B. cereus could maintain high activity [...] Read more.
Soil salinization is the leading environmental factor that restricts crop growth. This study studied the effects of Bacillus cereus (B. cereus) on growth, photosynthesis, and antioxidant metabolism in salt stressed-cucumber seedlings. The results showed that B. cereus could maintain high activity in the high salt environment (4% NaCl). B. cereus significantly increased plant height, stem diameter, fresh weight, and dry weight of cucumber seedlings under salt stress, and increased root vitality, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of cucumber seedlings under salt stress. B. cereus significantly increased the maximum photochemical quantum yield of photosystem II (Fv/Fm), the actual photochemical quantum yield (ΦPSII), and the quantum yield of regulatory energy dissipation Y (NPQ) under salt stress, which were 9.31%, 20.44%, and 5.22% higher than those under salt stress, respectively. The quantum yield of non-regulatory energy dissipation Y (NO) was reduced by 19.81%. Superoxidase (SOD), peroxidase (POD), and catalase (CAT) activities in leaves and roots of cucumber seedlings were significantly increased by B. cereus under salt stress. Compared with salt stress, SOD activities in leaves were significantly increased by 1.70% and 6.32% on the first and third days after treatment. At 1 d, 3 d, and 5 d after treatment, SOD activity in roots increased by 3.06%, 11.24%, and 3.00%, POD activity in leaves increased by 113.38%, 38.81%, and 52.89%, respectively. The POD activity in roots increased by 56.79% and 10.92% on the third and fifth days after treatment, the CAT activity in leaves increased by 8.50% and 25.55%, and the CAT activity in roots increased by 30.59% and 84.45%. Under salt stress, the H2O2 and MDA contents of seedlings treated with B. cereus decreased significantly. Compared with salt stress, the proline content in leaves decreased by 12.69%, 3.90%, and 13.12% at 1 d, 3 d, and 5 d, respectively, while the proline content in roots decreased by 44.94% and 60.08% at 3 d and 5 d, respectively. These results indicated that B. cereus could alleviate salt-induced inhibition of growth and photosynthesis by regulating antioxidant metabolism of cucumber seedlings and thus enhancing salt tolerance of cucumber seedlings. Full article
(This article belongs to the Section Biotic and Abiotic Stress)
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Article
Comprehensive Analysis of N6-Methyladenosine Regulatory Genes from Citrus grandis and Expression Profilings in the Fruits of “Huajuhong” (C. grandis “Tomentosa”) during Various Development Stages
Horticulturae 2022, 8(5), 462; https://doi.org/10.3390/horticulturae8050462 - 20 May 2022
Viewed by 384
Abstract
Citrus grandis “Tomentosa” (“Huajuhong”) is a famous traditional Chinese medicine. The aim of the present study is to provide a comprehensive characterization of the m6A regulatory genes from C. grandis, and examine their expression patterns in fruits of C. grandis [...] Read more.
Citrus grandis “Tomentosa” (“Huajuhong”) is a famous traditional Chinese medicine. The aim of the present study is to provide a comprehensive characterization of the m6A regulatory genes from C. grandis, and examine their expression patterns in fruits of C. grandis “Tomentosa” during various developmental stages. A total of 26 N6-methyladenosine (m6A) regulatory proteins were identified from the genome of C. grandis, which were distributed across nine chromosomes in C. grandis. Phylogenetic relationships revealed that all m6A regulatory genes were divided into groups of m6A writers, erasers, and readers. The m6A writer groups included CgMTA, CgMTB, and CgMTC three MTs (methyltransferases), one CgVIR (virilizer), one CgHAKAI (E3 ubiquitin ligase HAKAI), and one CgFIP37 (FKBP interacting protein 37). Moreover, 10 CgALKBH (α-ketoglutarate-dependent dioxygenase homolog) members (numbered from CgALKBH1 to CgALKBH10) and 10 CgECT (C-terminal region) members (numbered from CgECT1 to CgECT10) in C. grandis were identified as m6A erasers and readers, respectively. The domain structures and motif architectures among the groups of m6A writers, erasers, and readers were diverse. Cis-acting elements in the promoters of the 26 m6A regulatory genes predicted that the abscisic acid-responsive (ABA) element (ABRE) was present on the promoters of 19 genes. In addition, the expression profiles of all m6A regulatory genes were examined in the fruits of two varieties of C. grandis “Tomentosa” during different growth stages to give basic hints for further investigation of the function of the N6-methyladenosine regulatory genes in C. grandis “Tomentosa”. Full article
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Editorial
Nutritive Value, Polyphenolic Content, and Bioactive Constitution of Green, Red and Flowering Plants
Horticulturae 2022, 8(5), 461; https://doi.org/10.3390/horticulturae8050461 - 20 May 2022
Viewed by 389
Abstract
Plants, including vegetables are a well-known source of health-promoting phytochemicals (plant secondary metabolites) that take part in several physiological processes and play a major role in plant defense and adaptation, in particular plant–environment interactions [...] Full article
Article
Expression Analysis and Interaction Protein Screening of CRY1 in Strawberry
Horticulturae 2022, 8(5), 460; https://doi.org/10.3390/horticulturae8050460 - 20 May 2022
Viewed by 528
Abstract
Cryptochrome 1 (CRY1), a main blue light receptor protein, plays a significant role in several biological processes. However, the expression patterns and function of CRY1 in strawberry have not been identified. Here, the expression profile of CRY1 in different tissues and developmental stages [...] Read more.
Cryptochrome 1 (CRY1), a main blue light receptor protein, plays a significant role in several biological processes. However, the expression patterns and function of CRY1 in strawberry have not been identified. Here, the expression profile of CRY1 in different tissues and developmental stages of strawberry fruit, and expression patterns response to abiotic stresses (low temperature, salt and drought) were analyzed. Its subcellular localization, interaction proteins and heterologous overexpression in tobacco were also investigated. The results showed that CRY1 was mainly expressed in leaves and fruits with an expression peak at the initial red stage in strawberry fruit. Abiotic stresses could significantly induce the expression of CRY1. The CRY1 protein was located in both nucleus and cytoplasm. Five proteins (CSN5a-like, JAZ5, eIF3G. NF-YC9, and NDUFB9) interacting with CRY1 were discovered. Genes related flowering times, such as HY5 and CO, in three overexpressed FaCRY1 tobacco lines, were significantly upregulated. Taken together, our results suggested CRY1 have a broad role in biological processes in strawberry. Full article
(This article belongs to the Special Issue Omics Technologies and Their Applications in Vegetable Plant Research)
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Article
A Fruit Colour Development Index (CDI) to Support Harvest Time Decisions in Peach and Nectarine Orchards
Horticulturae 2022, 8(5), 459; https://doi.org/10.3390/horticulturae8050459 - 19 May 2022
Viewed by 490
Abstract
Fruit skin colour is one of the most important visual fruit quality parameters driving consumer preferences. Proximal sensors such as machine vision cameras can be used to detect skin colour in fruit visible in collected images, but their accuracy in variable orchard light [...] Read more.
Fruit skin colour is one of the most important visual fruit quality parameters driving consumer preferences. Proximal sensors such as machine vision cameras can be used to detect skin colour in fruit visible in collected images, but their accuracy in variable orchard light conditions remains a practical challenge. This work aimed to derive a new fruit skin colour attribute—namely a Colour Development Index (CDI), ranging from 0 to 1, that intuitively increases as fruit becomes redder—to assess colour development in peach and nectarine fruit skin. CDI measurements were generated from high-resolution images collected on both east and west sides of the canopies of three peach and one nectarine cultivars using the commercial mobile platform Cartographer (Green Atlas). Fruit colour (RGB values) was extracted from the central pixels of detected fruit and converted into a CDI. The repeatability of CDI measurements under different light environments was tested by scanning orchards at different times of the day. The effects of cultivar and canopy side on CDI were also determined. CDI data was related to the index of absorbance difference (IAD)—an index of chlorophyll degradation that was correlated with ethylene emission—and its response to time from harvest was modelled. The CDI was only significantly altered when measurements were taken in the middle of the morning or in the middle of the afternoon, when the presence of the sun in the image caused significant alteration of the image brightness. The CDI was tightly related to IAD, and CDI values plateaued (0.833 ± 0.009) at IAD ≤ 1.20 (climacteric onset) in ‘Majestic Pearl’ nectarine, suggesting that CDI thresholds show potential to be used for harvest time decisions and to support logistics. In order to obtain comparable CDI datasets to study colour development or forecast harvest time, it is recommended to scan peach and nectarine orchards at night, in the early morning, solar noon, or late afternoon. This study found that the CDI can serve as a standardised and objective skin colour index for peaches and nectarines. Full article
(This article belongs to the Special Issue Precision Management of Fruit Trees)
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Article
Genetic Diversity and Genome-Wide Association Study of Architectural Traits of Spray Cut Chrysanthemum Varieties
Horticulturae 2022, 8(5), 458; https://doi.org/10.3390/horticulturae8050458 - 19 May 2022
Viewed by 472
Abstract
The architecture of spray cut chrysanthemum is crucial for the quality and quantity of cut flower production. However, the mechanism underlying plant architecture still needs to be clarified. In this study, we measured nine architecture-related traits of 195 spray cut chrysanthemum varieties during [...] Read more.
The architecture of spray cut chrysanthemum is crucial for the quality and quantity of cut flower production. However, the mechanism underlying plant architecture still needs to be clarified. In this study, we measured nine architecture-related traits of 195 spray cut chrysanthemum varieties during a two-year period. The results showed that the number of upper primary branches, number of lateral flower buds and primary branch length widely varied. Additionally, plant height had a significant positive correlation with number of leaf nodes and total number of lateral buds. Number of upper primary branches had a significant negative correlation with primary branch diameter, primary branch angle and primary branch length. Plant height, total number of lateral buds, number of upper primary branches, stem diameter, primary branch diameter and primary branch length were vulnerable to environmental impacts. All varieties could be divided into five categories according to cluster analysis, and the typical plant architecture of the varieties was summarized. Finally, a genome-wide association study (GWAS) was performed to find potential functional genes. Full article
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Article
Genome-Wide Identification and Expression Analysis of AMT Gene Family in Apple (Malus domestica Borkh.)
Horticulturae 2022, 8(5), 457; https://doi.org/10.3390/horticulturae8050457 - 19 May 2022
Viewed by 376
Abstract
Ammonium is one of the prevalent nitrogen sources for growth and development of higher plants. Ammonium acquisition from soil is facilitated by ammonium transporters (AMTs), which are plasma membrane proteins that exclusively transport ammonium/ammonia. However, the functional characteristics and molecular mechanisms of AMTs [...] Read more.
Ammonium is one of the prevalent nitrogen sources for growth and development of higher plants. Ammonium acquisition from soil is facilitated by ammonium transporters (AMTs), which are plasma membrane proteins that exclusively transport ammonium/ammonia. However, the functional characteristics and molecular mechanisms of AMTs in apple remain unclear. In this work, 15 putative AMT genes were identified and classified into four clusters (AMT1–AMT4) in apple. According to expression analysis, these AMTs had varying expressions in roots, leaves, stems, flowers and fruits. Some of them were strongly affected by diurnal cycles. AMT genes showed multiple transcript patterns to N regimes and were quite responsive to osmotic stress. In addition, phosphorylation analysis revealed that there were some conserved phosphorylation residues within the C-terminal of AMT proteins. Furthermore, detailed research was conducted on AMT1;2 functioning by heterologous expression in yeast. The present study is expected to provide basic bioinformatic information and expression profiles for the apple AMT family and to lay a basis for exploring the functional roles and regulation mechanisms of AMTs in apple. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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Article
Encapsulation in Calcium Alginate of Nodes from Stolons of Mentha spicata L.
Horticulturae 2022, 8(5), 456; https://doi.org/10.3390/horticulturae8050456 - 19 May 2022
Viewed by 417
Abstract
It is well known that the products of encapsulation (multifunctional beads and synthetic seeds) can be used as innovative technological tools to integrate micropropagation both for plant germplasm conservation and to simplify the management of propagation materials in nurseries. Nevertheless, the usual concept [...] Read more.
It is well known that the products of encapsulation (multifunctional beads and synthetic seeds) can be used as innovative technological tools to integrate micropropagation both for plant germplasm conservation and to simplify the management of propagation materials in nurseries. Nevertheless, the usual concept of encapsulation concerns the use of initial in vitro derived explants. In this study, for the first time, in vivo derived organs of Mentha spicata L., obtained through the excision of fragments (nodes) from stolons of cultivated mother plants, were employed. The artificial endosperm had a tenfold reduced concentration of Murashige and Skoog (MS) substrate, with the addition of sucrose (5 g L−1), 6-benzyl-aminopurine (BAP) (0.1 mg L−1) and 1-naphthalene acetic acid (NAA) (0.01 mg L−1). Moreover, the calcium alginate matrix was enriched with different thiophanate-methyl (TM) concentrations (0, 10, 50, 100 and 200 mg L−1) in order to prevent possible contamination during the conversion in nonsterile conditions. Interesting results were obtained encapsulating every single node of fresh stolon as a bipolar propagule able to develop a whole plantlet (conversion), as the coated seed in other species. The synthetic seeds of spearmint without TM in the artificial endosperm showed a satisfactory ability to convert (56.7%) into plantlets after sowing in soil under nonsterile conditions. TM at 100 and 200 mg L−1 negatively affected the total emergence, which decreased to 30.0 and 33.3%, respectively. In general, in the artificial seeds without TM, higher values for most of the aboveground and belowground plants parameters were recorded compared to naked nodes. Full article
(This article belongs to the Special Issue Application of Tissue Culture to Horticulture)
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Article
Effect of Fruit Weight and Fruit Locule Number in Bell Pepper on Industrial Waste and Quality of Roasted Pepper
Horticulturae 2022, 8(5), 455; https://doi.org/10.3390/horticulturae8050455 - 19 May 2022
Viewed by 401
Abstract
Bell pepper (Capsicum annuum L.), one of the most consumed vegetables worldwide, shows great differences between its diverse varieties. These differences affect the fruit type, size and shape. Food preservation techniques prolong the availability of sweet pepper. Roasted pepper is a product [...] Read more.
Bell pepper (Capsicum annuum L.), one of the most consumed vegetables worldwide, shows great differences between its diverse varieties. These differences affect the fruit type, size and shape. Food preservation techniques prolong the availability of sweet pepper. Roasted pepper is a product marketed with the European recognition of Protected Geographical Indication ‘Pimiento Asado del Bierzo’. The objective of this work was to analyse the effect of the fruit weight and fruit locule number of the industrial fresh pepper on quality and roasted pepper yield. Large trilocular fruits and large tetralocular fruits reached higher roast yield and uniformity than small trilocular fruits. Regardless of fruit locule number and fruit weight, the overall quality of all the samples of roasted pepper was categorised as very good. Large tetralocular and large trilocular fruits are the most appropriate peppers for industrial purposes, whereas small trilocular fruits should be intended for the fresh product market. This easy method of sorting bell pepper fruit attending to fruit weight will decrease the amount of pepper waste in the industrial roasting process (around 18%), while maintaining the high overall quality of the final product. Moreover, the faster peeling of large peppers will also contribute to increasing the productivity of the industrial processing of roasted pepper. Full article
(This article belongs to the Special Issue Advances in Fruit Quality Formation and Regulation)
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Article
Planting Date and Different N-Fertilization Rates Differently Modulate Agronomic and Economic Traits of a Sicilian Onion Landrace and of a Commercial Variety
Horticulturae 2022, 8(5), 454; https://doi.org/10.3390/horticulturae8050454 - 18 May 2022
Viewed by 424
Abstract
The onion is one of the most widespread bulb vegetables worldwide. Onion cultivation is common in Sicily, as is the use of local genotypes. Cultivation practices are of particular interest in optimizing yield, quality, and profits. The aim of this study was to [...] Read more.
The onion is one of the most widespread bulb vegetables worldwide. Onion cultivation is common in Sicily, as is the use of local genotypes. Cultivation practices are of particular interest in optimizing yield, quality, and profits. The aim of this study was to assess the agronomic response of a Sicilian landrace (Bianca Calda di Comiso, coded L1) and a commercial variety (Bianca di Maggio, coded V1) to different planting dates and N fertilization rates. An economic appraisal was also performed. The two genotypes were assessed using an experimental split-split-plot design with four levels of nitrogen rates (0, 80, 160, and 220 kg N ha−1) and two different planting dates (8 October 2005 to 9 October 2006 for the early planting date, and 27 December 2005 to 30 December 2006 for the traditional planting date). The marketable yield and production parameters were significantly influenced by the nitrogen dose: higher doses led to a higher total yield, with yield peaks above 60 t ha−1 and the marketable yield ranging from 23% to 54%. Simultaneously, decreases in the firmness (from 7% to 19%) and scale content (from 1% to 3%) were also reported. The L1 landrace showed a higher production than the V1 variety. The crop year did not significantly affect the results, and the traditional planting date appeared to be the most suitable choice in obtaining the best agronomic response. Economic analysis showed that the L1 landrace, with high-N application treatments, produced greater net benefits and marginal rates of return. Thus, the L1 landrace exposed to the highest dosages of nitrogen (160 or 220 kg ha−1) and transplanted during the traditional planting period is the best choice from agronomic and economic points of view. Full article
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Article
Characterisation of the Complete Chloroplast Genomes of Seven Hyacinthus orientalis L. Cultivars: Insights into Cultivar Phylogeny
Horticulturae 2022, 8(5), 453; https://doi.org/10.3390/horticulturae8050453 - 18 May 2022
Viewed by 572
Abstract
To improve agricultural performance and obtain potential economic benefits, an understanding of phylogenetic relationships of Hyacinthus cultivars is needed. This study aims to revisit the phylogenetic relationships of Hyacinthus cultivars using complete chloroplast genomes. Nine chloroplast genomes were de novo sequenced, assembled and [...] Read more.
To improve agricultural performance and obtain potential economic benefits, an understanding of phylogenetic relationships of Hyacinthus cultivars is needed. This study aims to revisit the phylogenetic relationships of Hyacinthus cultivars using complete chloroplast genomes. Nine chloroplast genomes were de novo sequenced, assembled and annotated from seven cultivars of Hyacinthus orientalis and two Scilloideae species including Bellevalia paradoxa and Scilla siberica. The chloroplast genomes of Hyacinthus cultivars ranged from 154,458 bp to 154,641 bp, while those of Bellevalia paradoxa and Scilla siberica were 154,020 bp and 154,943 bp, respectively. Each chloroplast genome was annotated with 133 genes, including 87 protein-coding genes, 38 transfer RNA genes and 8 ribosomal RNA genes. Simple sequence repeats AAGC/CTTG and ACTAT/AGTAT were identified only in ‘Eros’, while AAATC/ATTTG were identified in all cultivars except ‘Eros’. Five haplotypes were identified based on 460 variable sites. Combined with six other previously published chloroplast genomes of Scilloideae, a sliding window analysis and a phylogenetic analysis were performed. Divergence hotspots ndhA and trnG-UGC were identified with a nucleotide diversity threshold at 0.04. The phylogenetic positions of Hyacinthus cultivars were different from the previous study using ISSR. Complete chloroplast genomes serve as new evidence in Hyacinthus cultivar phylogeny, contributing to cultivar identification, preservation and breeding. Full article
(This article belongs to the Topic Plant Breeding, Genetics and Genomics)
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Article
Brassinolide Maximized the Fruit and Oil Yield, Induced the Secondary Metabolites, and Stimulated Linoleic Acid Synthesis of Opuntia ficus-indica Oil
Horticulturae 2022, 8(5), 452; https://doi.org/10.3390/horticulturae8050452 - 18 May 2022
Cited by 1 | Viewed by 446
Abstract
Prickly pear plant is widely cultivated in arid and semi-arid climates. Its fruits are rich in polyphenols, proteins, vitamin C, minerals, fatty acids, and amino acids. The oil extracted from the seeds also has a significant proportion of linoleic acid (ω6) and might [...] Read more.
Prickly pear plant is widely cultivated in arid and semi-arid climates. Its fruits are rich in polyphenols, proteins, vitamin C, minerals, fatty acids, and amino acids. The oil extracted from the seeds also has a significant proportion of linoleic acid (ω6) and might be employed as a therapeutic raw material. The potential of enhancing fruit yield, increasing bioactive compounds of the fruit pulp, and improving the unsaturated fatty acid content of prickly pear oilseed by using the foliar application of brassinolide as a plant growth regulator was the main goal of this study. Prickly pear plants were foliar sprayed with a brassinolide solution at concentrations of 0, 1, 3, and 5 mg L−1. The plant performance was significantly improved following brassinolide applications, as compared with untreated plants. The plants subjected to 5 mg L−1 application exhibited 183 and 188% stimulation in the fruit yield, and 167 and 172% in the seed yield for the first and second seasons, respectively. The highest concentration of phenolic, flavonoid, protein, vitamin C, and maximum antioxidant activity in the fruit pulp was observed following 5 mg L−1 brassinolide treatment. The oil yield has been increased by 366 and 353% following brassinolide at a 5 mg L−1 level over control plants. Linoleic, oleic, and palmitic acids are the major components in prickly pear seed oil. Brassinolide foliar spraying induced an alternation in the fatty acid profile, as linoleic and oleic acids exhibited 5 and 4% higher following 5 mg L−1 application as compared with untreated plants. In conclusion, the treatment of 5 mg L−1 brassinolide improved the growth and quality of prickly pear plants by boosting fruit and seed yields, increasing active component content in the fruit pulp, improving mineral content, and increasing oil production and linoleic acid proportion. Full article
(This article belongs to the Special Issue Sustainable Production and Utilization of Oilseed Crops)
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Review
Application of Elicitors in Grapevine Defense: Impact on Volatile Compounds
Horticulturae 2022, 8(5), 451; https://doi.org/10.3390/horticulturae8050451 - 17 May 2022
Viewed by 421
Abstract
Elicitors as alternatives to agrochemicals are widely used as a sustainable farming practice. The use of elicitors in viticulture to control disease and improve phenolic compounds is widely recognized in this field. Concurrently, they also affect other secondary metabolites, such as aroma compounds. [...] Read more.
Elicitors as alternatives to agrochemicals are widely used as a sustainable farming practice. The use of elicitors in viticulture to control disease and improve phenolic compounds is widely recognized in this field. Concurrently, they also affect other secondary metabolites, such as aroma compounds. Grape and wine aroma compounds are an important quality factor that reflects nutritional information and influences consumer preference. However, the effects of elicitors on aroma compounds are diverse, as different grape varieties respond differently to treatments. Among the numerous commercialized elicitors, some have proven very effective in improving the quality of grapes and the resulting wines. This review summarizes some of the elicitors commonly used in grapevines for protection against biotic and abiotic stresses and their impact on the quality of volatile compounds. The work is intended to serve as a reference for growers for the sustainable development of high-quality grapes. Full article
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Article
Evaluation of the Effects of Culture Media and Light Sources on In Vitro Growth of Brassavola nodosa (L.) Lindl. Hybrid
Horticulturae 2022, 8(5), 450; https://doi.org/10.3390/horticulturae8050450 - 17 May 2022
Viewed by 412
Abstract
Culture medium and light are important factors that affect the process of in vitro propagation of plants. Particularly for orchids, diverse culture media have been evaluated for micropropagation of many species and hybrids. More recently, light-emitting diodes (LEDs) have become widely used in [...] Read more.
Culture medium and light are important factors that affect the process of in vitro propagation of plants. Particularly for orchids, diverse culture media have been evaluated for micropropagation of many species and hybrids. More recently, light-emitting diodes (LEDs) have become widely used in agriculture, including micropropagation commercial operations, resulting in increased production and reduced costs compared to traditional fluorescent lights. Brassavola nodosa (L.) Lindl. is an orchid, with great potential for commercialization as a potted flowering plant due to the beauty and fragrance of its inflorescences. In this study, we evaluated the effects of culture media (VW, MS, and ½ MS) and light sources (three LED sources and one fluorescent light source) on the micropropagation of B. nodosa orchids. VW medium resulted in the best growth and development of in vitro shoots compared to MS and ½ MS media. Light sources with lower intensity, such as LED-3 (80 μmol m−2 s−1 PPFD) resulted in the best plant performance in vitro, while LED-2 (1015 μmol m−2 s−1 PPFD) showed the best plant performance ex vitro. Rooting was obtained in vitro without the need for a rooting phase. Survival ex vitro was 100%, with the successful growth and development of in vitro-derived plantlets during acclimatization. Full article
(This article belongs to the Special Issue Innovation in Propagation and Cultivation of Ornamental Plants)
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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
Viewed by 417
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
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
Viewed by 426
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
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 465
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
Molecular Cloning of a TCHQD Class Glutathione S-Transferase and GST Function in Response to GABA Induction of Melon Seedlings under Root Hypoxic Stress
Horticulturae 2022, 8(5), 446; https://doi.org/10.3390/horticulturae8050446 - 17 May 2022
Viewed by 457
Abstract
Glutathione-S-transferase (GST), a versatile enzyme that occurs widely in plants, plays a key role in plant resistance to environmental stresses. Previous results have demonstrated that GST proteins are involved in alleviating root hypoxic injury caused by gamma-aminobutyric acid (GABA); however, the induction mechanism [...] Read more.
Glutathione-S-transferase (GST), a versatile enzyme that occurs widely in plants, plays a key role in plant resistance to environmental stresses. Previous results have demonstrated that GST proteins are involved in alleviating root hypoxic injury caused by gamma-aminobutyric acid (GABA); however, the induction mechanism of the GST gene in the melon under root hypoxic stress and its functional mechanisms remain unclear. In this study, based on gene cloning and bioinformatics analysis, GST gene expression and activity and glutathione (GSH) content were assessed under root hypoxic and normoxic conditions with or without GABA. The results showed that the CmGST locus includes an 804 bp gene sequence that encodes 267 amino acids. The sequence was highly similar to those of other plant TCHQD GSTs, and the highest value (94%) corresponded to Cucumis sativus. Real-time PCR results showed that the CmGST gene was induced by root hypoxic stress and GABA, and this induction was accompanied by increased GST activity and GSH content. Root hypoxic stress significantly upregulated CmGST expression in melon roots (0.5–6 d), stems, and leaves (0.5–4 d), and GST activity and GSH content were also significantly increased. Exogenous GABA treatment upregulated CmGST gene expression, GST activity, and GSH content, particularly under root hypoxic conditions. As a result, CmGST expression in GABA-treated roots and leaves at 0.5–4 d and stems at 0.5–6 d was significantly higher than that under root hypoxic stress alone. This study provides evidence that the TCHQD CmGST may play a vital role in how GABA increases melon hypoxia tolerance by upregulating gene expression and improving metabolism. Full article
(This article belongs to the Special Issue Advances in Protected Vegetable Cultivation)
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Article
Effects of Vermicompost Substrates and Coconut Fibers Used against the Background of Various Biofertilizers on the Yields of Cucumis melo L. and Solanum lycopersicum L.
Horticulturae 2022, 8(5), 445; https://doi.org/10.3390/horticulturae8050445 - 16 May 2022
Viewed by 580
Abstract
Vermicompost has been promoted as a viable substrate component owing to its physicochemical properties, nutrient richness, and status as an excellent soil improver. It is considered the best organic fertilizer and is more eco-friendly than chemical fertilizers. Plant-growth-promoting microorganisms (PGPMs) are defined as [...] Read more.
Vermicompost has been promoted as a viable substrate component owing to its physicochemical properties, nutrient richness, and status as an excellent soil improver. It is considered the best organic fertilizer and is more eco-friendly than chemical fertilizers. Plant-growth-promoting microorganisms (PGPMs) are defined as plant biofertilizers that improve nutritional efficiency—that is, they transform nutrients within substrates from organic to inorganic forms, making them available for plants. The main objective of this research study is to evaluate the effects of the application of three PGPM microbial consortia on different mixtures of organic substrates based on vermicompost (V) and coconut fiber (CF) on two different horticultural crops. We performed a yield analysis and drainage nutrient tests and determined the plant nutritional status and enzymatic activity in organic substrates based on the two crops, Cucumis melo L. and Solanum lycopersicum L. A multivariate analysis of variance and principal component analysis was conducted using substrate types and PGPMs as factors. Differences (p < 0.05) in yield, dehydrogenase activity, the nutrient concentrations in a petiole sap, and drainage were observed at 30, 60, 75, and 90 days after transplant. PGPMs such as Trichoderma sp. and plant-growth-promoting rhizobacteria (PGPR) in organic substrates (40V + 60CF) can significantly improve the nutritional status of plants for use in organic soilless container agriculture. Biofertilization with PGPMs and suitable mixtures of organic substrates together with aqueous extracts (tea) of vermicompost, as nutrient solutions applied by fertigation, has allowed us to achieve an adequate level of production through environmentally friendly techniques. The results obtained allowed us to affirm that it was possible to replace conventional fertilization using no chemical products and ensure adequate crop nutrition by supplying main macronutrients with organic sources and biofertilizers. Full article
(This article belongs to the Section Protected Culture)
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Article
Synergism of Industrial and Agricultural Waste as a Suitable Carrier Material for Developing Potential Biofertilizer for Sustainable Agricultural Production of Eggplant
Horticulturae 2022, 8(5), 444; https://doi.org/10.3390/horticulturae8050444 - 16 May 2022
Viewed by 449
Abstract
The study investigates biochar from agriculture waste and flyash from coal power station as possible carrier materials for two plant growth-promoting (PGP) bacterial strains Burkholderia sp. L2 and Bacillus sp. A30 for enhanced eggplant growth and yield. Biochar-based biofertilizers with/without flyash showed higher [...] Read more.
The study investigates biochar from agriculture waste and flyash from coal power station as possible carrier materials for two plant growth-promoting (PGP) bacterial strains Burkholderia sp. L2 and Bacillus sp. A30 for enhanced eggplant growth and yield. Biochar-based biofertilizers with/without flyash showed higher viability up to 270 days of storage period. The maximum percentage of seed germination was observed in L2-based biochar and flyash + biochar (1:1) bifertilizer. Moreover, the L2 + biochar+flyash produced a maximum percentage increase in fruit yield with significant (p < 0.05) improvement in plant growth parameters. Post-harvest soil status also showed enhanced physical (water holding capacity, moisture content), chemical (pH, electrical conductivity, NPK), and dehydrogenase activity. The study suggests that biofertilizer of L2 strain with agriculture waste generated biochar and flyash as carrier materials can tremendously enhance the productivity of eggplant and could act as a substitute for chemical fertilizer thus solving their disposal problem by sustainable waste management. Full article
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Article
Larvicidal Activity and Phytochemical Profiling of Sweet Basil (Ocimum basilicum L.) Leaf Extract against Asian Tiger Mosquito (Aedes albopictus)
Horticulturae 2022, 8(5), 443; https://doi.org/10.3390/horticulturae8050443 - 16 May 2022
Viewed by 494
Abstract
Applying larvicides to interrupt a mosquito’s life cycle is an important strategy for vector control. This study was conducted to evaluate the larvicidal properties of the hexane extract of sweet basil (Ocimum basilicum L.; family Lamiaceae) leaves against the wild strain of [...] Read more.
Applying larvicides to interrupt a mosquito’s life cycle is an important strategy for vector control. This study was conducted to evaluate the larvicidal properties of the hexane extract of sweet basil (Ocimum basilicum L.; family Lamiaceae) leaves against the wild strain of Asian tiger mosquito, Aedes albopictus (Skuse). Third instar larvae (20 larvae/replicate, n = 3) were exposed to different concentrations of the extract (6.25–200 µg/mL), and the mortality rate was recorded. Probit analysis showed that the median lethal concentration and 95% lethal concentration of the extract were 16.0 (10.9–22.1) and 53.0 (34.6–136.8) µg/mL, respectively, after 24 h exposure. Only the fractions F3, F4, and F5 from the column chromatography displayed high mortality rates of 91.7–100% at 25.0 µg/mL after 24 h exposure. Subsequent column chromatography from the pooled fraction yielded two active subfractions, H-F345-S2 and H-F345-S3, with mortality rates of 100% and 98.3 ± 2.9%, respectively, at 12.5 µg/mL. Gas chromatography–mass spectrometry analysis unveiled that methyl chavicol, 2-(2-butoxyethoxy)ethanol, cedrelanol, methyl eugenol, 2,4,di-tert-butylphenol, and phytol were the major components in both subfractions with some of them being reported as larvicidal compounds. The results suggest that sweet basil has substantial larvicidal activity against Ae. albopictus mosquito and is a potential source of naturally derived larvicide. Full article
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Article
Volatile Oil Components of Laurel (Laurus nobilis L.) Leaves Obtained from Plants Cultivated under Salinity Stress Conditions
Horticulturae 2022, 8(5), 442; https://doi.org/10.3390/horticulturae8050442 - 16 May 2022
Viewed by 444
Abstract
Laurel (Laurus nobilis L.) is a strict endemic species of natural vegetation of the Mediterranean region, which is known for its medicinal, aromatic, forestry, ornamental and culinary properties. This species produces valuable essential oil (EO). The content of EO and its composition [...] Read more.
Laurel (Laurus nobilis L.) is a strict endemic species of natural vegetation of the Mediterranean region, which is known for its medicinal, aromatic, forestry, ornamental and culinary properties. This species produces valuable essential oil (EO). The content of EO and its composition depend on different factors, e.g., genetic, cultural practices and environmental conditions. Among these, salt stress is a major limiting factor, which affects almost all plant functions. Similar to essential oils (EOs), biotic and abiotic stresses may stimulate or inhibit the emission of volatile compounds (VCs) in plant materials, suggesting that these substances can be responsible on stress defense strategies. Therefore, an experiment was conducted to assess the effect of different NaCl concentrations (0, 50, 100 and 150 mM) of the irrigation water on VCs of laurel leaves. Our results showed that salt stress affected the volatile metabolites compounds, mainly the major ones. For instance, 1,8-cineole and linalool were negatively affected by high salinity levels, while the opposite was observed for α-terpenyl acetate and methyl eugenol. The proportion of grouped compounds of laurel VCs also differed among the studied treatments. The relative content of oxygenated monoterpenes and monoterpene hydrocarbons, respectively the first and the second largest groups, decreased with increasing NaCl concentration. Differently, the relative amount of sesquiterpene hydrocarbon group increased, especially at 100 mM NaCl. These findings indicate that the cultivation of laurel in marginal lands, characterized by high salinity or low-quality water, must be carefully evaluated because it significantly varies the quality of its products. Full article
(This article belongs to the Special Issue Production and Quality of Medicinal and Aromatic Plants)
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Article
Genetic Diversity and Streptomycin Sensitivity in Xanthomonas axonopodis pv. punicae Causing Oily Spot Disease in Pomegranates
Horticulturae 2022, 8(5), 441; https://doi.org/10.3390/horticulturae8050441 - 16 May 2022
Viewed by 397
Abstract
Xanthomonas axonopodis pv. punicae (Xap) causes bacterial blight disease in pomegranates, often leading to 60–80% economic loss. In absence of a suitable Xap-resistant variety, the near-monoculture of the susceptible variety, Bhagwa, has aggravated the problem further. In recent times, Xap has spread to [...] Read more.
Xanthomonas axonopodis pv. punicae (Xap) causes bacterial blight disease in pomegranates, often leading to 60–80% economic loss. In absence of a suitable Xap-resistant variety, the near-monoculture of the susceptible variety, Bhagwa, has aggravated the problem further. In recent times, Xap has spread to different geographical regions, indicating the wide adaptability of the pathogen. Moreover, lower sensitivity of Xap towards streptocycline containing streptomycin sulphate and tetracycline sulphate (9:1) under field conditions is frequently reported. Therefore, the current study was undertaken to assess the genetic variability of Xap isolates using SSR markers, their in vitro sensitivity towards streptomycin was evaluated, and the probable molecular basis of acquired resistance was studied. Two highly diverse isolates showed extreme differences in their pathogenicity, indicating the highly evolving nature of the pathogen. Moreover, all the isolates showed less than 50% growth inhibition on media containing 1500 µg/mL streptomycin, indicating a lower level of antibiotic sensitivity. On the molecular level, 90% of the isolates showed the presence of strA-strB genes involved in streptomycin metabolism. Additionally, G to A transitions were observed in the rpsL gene in some of the isolates. The molecular data suggest that horizontal gene transfer (strAB) and/or spontaneous gene mutation (in rpsL) could be responsible for the observed lower sensitivity of Xap towards streptomycin. Full article
(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)
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Article
Extensive Sampling Provides New Insights into Phylogenetic Relationships between Wild and Domesticated Zanthoxylum Species in China
Horticulturae 2022, 8(5), 440; https://doi.org/10.3390/horticulturae8050440 - 14 May 2022
Viewed by 594
Abstract
Zanthoxylum, belonging to the Rutaceae family, is widely distributed in tropical and subtropical regions. The genus has high economic value as spices, oils, medicinal plants, and culinary applications. Zanthoxylum has a long history of domestication and cultivation in China. However, the phylogenetic [...] Read more.
Zanthoxylum, belonging to the Rutaceae family, is widely distributed in tropical and subtropical regions. The genus has high economic value as spices, oils, medicinal plants, and culinary applications. Zanthoxylum has a long history of domestication and cultivation in China. However, the phylogenetic relationships and origin of wild and cultivated Zanthoxylum species in China remain largely unknown. Moreover, there is still no clear molecular phylogenetic system for Zanthoxylum species. Herein, 373 Zanthoxylum samples were collected from all presently known provenances of Zanthoxylum in China. In this study, four chloroplast DNA (cpDNA) markers (matK, ndhH, psbB, rbcL) were used to comprehensively analyze the genetic diversity, relatedness, and geographical origin of Chinese Zanthoxylum species. The results were as follows: (1) The aligned length of the four pairs of cpDNA sequences was 3836 bp, and 68 haplotypes were identified according to 219 variable polymorphic sites, including 90 singleton variable sites, 129 parsimony informative sites, 3 Indels (insertions and deletions). (2) Phylogenetic tree and haplotype network strongly supported the division of Zanthoxylum species consistent with the taxonomic recognition of five species: Z. bungeanum, Z. piasezkii, Z. piperitum, Z. armatum, and Z. micranthum. (3) Divergence time estimation suggested that Zanthoxylum genus originated from the Late Eocene, and most Zanthoxylum species diverged after the Middle Miocene. (4) Haplotype 16 (H16) was at the bottom of the phylogenetic tree, had higher haplotype diversity (Hd) and nucleotide polymorphism (Pi) than other haplotypes, and was located in the center of the network figure. Therefore, we deduced that the cultivated Zanthoxylum species may originate in Zhouqu County, Gansu Province, China. Meanwhile, our research provided a scientific basis for the identification and breeding programs of Chinese Zanthoxylum species. Full article
(This article belongs to the Topic Plant Breeding, Genetics and Genomics)
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Review
Aspects of In Vitro Plant Tissue Culture and Breeding of Asparagus: A Review
Horticulturae 2022, 8(5), 439; https://doi.org/10.3390/horticulturae8050439 - 14 May 2022
Viewed by 696
Abstract
In vitro plant tissue culture and biotechnology used to assist and support the development of plant breeding when classical methods of propagation must be accelerated or it was necessary to overcome barriers inaccessible by classical approaches. In asparagus, to improve multiple breeding tasks, [...] Read more.
In vitro plant tissue culture and biotechnology used to assist and support the development of plant breeding when classical methods of propagation must be accelerated or it was necessary to overcome barriers inaccessible by classical approaches. In asparagus, to improve multiple breeding tasks, a high number of in vitro methods have been used, such as plant regeneration methods through organogenesis, embryogenesis, manipulation of ploidy, protoplast isolation, genetic manipulation (protoplast fusion, genetic transformation), embryo rescue and germplasm preservation (in vitro, in vitro slow growth, cryopreservation). Plant tissue culture methods can overcome multiple problems in asparagus breeding such as, barriers of self and cross-incompatibility between asparagus species through embryo rescue of interspecific hybrids and protoplast fusion or genetic transformation, introgression of new genes, clonal propagation of elite genotypes of asparagus, mass screening, and the generation of haploid and polyploid genotypes, among others, becoming the tool of choice for asparagus breeding programs. Some of these in vitro methods are still under development. Full article
(This article belongs to the Special Issue Advances in Asparagus Production, Genomics and Breeding)
Article
Indirect Quantitative Analysis of Biochemical Parameters in Banana Using Spectral Reflectance Indices Combined with Machine Learning Modeling
Horticulturae 2022, 8(5), 438; https://doi.org/10.3390/horticulturae8050438 - 14 May 2022
Viewed by 465
Abstract
The primary issues in collecting biochemical information in a large area using chemical laboratory procedures are low throughput, hard work, time-consuming, and requiring several samples. Thus, real-time and precise estimation of biochemical variables of various fruits using a proximal remote sensing based on [...] Read more.
The primary issues in collecting biochemical information in a large area using chemical laboratory procedures are low throughput, hard work, time-consuming, and requiring several samples. Thus, real-time and precise estimation of biochemical variables of various fruits using a proximal remote sensing based on spectral reflectance is critical for harvest time, artificial ripening, and food processing, which might be beneficial economically and ecologically. The main goal of this study was to assess the biochemical parameters of banana fruits such as chlorophyll a (Chl a), chlorophyll b (Chl b), respiration rate, total soluble solids (TSS), and firmness using published and newly developed spectral reflectance indices (SRIs), integrated with machine learning modeling (Artificial Neural Networks; ANN and support vector machine regression; SVMR) at different ripening degrees. The results demonstrated that there were evident and significant differences in values of SRIs at different ripening degrees, which may be attributed to the large variations in values of biochemical parameters. The newly developed two-band SRIs are more effective at measuring different biochemical parameters. The SRIs that were extracted from the visible (VIS), near-infrared (NIR), and their combination showed better R2 with biochemical parameters. SRIs combined with ANN and SVMR would be an effective method for estimating five biochemical parameters in the calibration (Cal.) and validation (Val.) datasets with acceptable accuracy. The ANN-TSS-SRI-13 model was built to determine TSS with greater performance expectations (R2 = 1.00 and 0.97 for Cal. and Val., respectively). Furthermore, the model ANN-Firmness-SRI-15 was developed for determining firmness, and it performed better (R2 = 1.00 and 0.98 for Cal. and Val., respectively). In conclusion, this study revealed that SRIs and a combination approach of ANN and SVMR models would be a useful and excellent tool for estimating the biochemical characteristics of banana fruits. Full article
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Article
Production of Triploid Germplasm by Inducing 2n Pollen in Longan
Horticulturae 2022, 8(5), 437; https://doi.org/10.3390/horticulturae8050437 - 13 May 2022
Viewed by 451
Abstract
Longan (Dimocarpus longan Lour.) is of great economic significance in South China for its unique taste and nutritional properties. However, longan breeding is mainly based on seedling selection, which generally results in small fruits, low flesh recovery, and few seedless germplasm. Triploid [...] Read more.
Longan (Dimocarpus longan Lour.) is of great economic significance in South China for its unique taste and nutritional properties. However, longan breeding is mainly based on seedling selection, which generally results in small fruits, low flesh recovery, and few seedless germplasm. Triploid breeding is a central way to improve these problems. In this study, microspore chromosomes were doubled by colchicine and high-temperature treatment to create triploids in longans. The relationship between the development process of male gametophyte of longans and the morphological changes of male flower buds was established. Cytological observation showed that when the male flower buds were in stage I (when the diameter of the flower bud is 1.4–2.0 mm), most of the microspores were at the pachytene to diakinesis stage of meiosis, and the chromosome doubling induction effect was the best at this stage. The results showed that the 2n pollen rate induced by a high temperature of about 38 °C was higher than that induced by colchicine treatment. The highest 2n pollen rate was 5.7% and 5.5% based on the microscopic measurement method and the abnormal separation in tetrad stage estimation method, respectively. Four triploids were successfully obtained from artificial pollination with 2n pollen, with a triploid induction rate of 0.6%. This study will promote ploidy breeding in longan. Full article
(This article belongs to the Special Issue Advances in Tropical Fruit Cultivation and Breeding)
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