Horticulturae

18 pages, 3967 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Changes in Herbaceous Peony Growth and Soil Microbial Diversity in Different Growing and Replanting Years Based on High-Throughput Sequencing

by Yang Li, Zemiao Liu, Lijin Yang, Xiao Yang, Yajie Shi, Xue Li, Lingling Dong, Chengshu Zheng, Dongliang Zhang and Xia Sun

Horticulturae 2023, 9(2), 220; https://doi.org/10.3390/horticulturae9020220 - 7 Feb 2023

Viewed by 1512

Abstract

The herbaceous peony (Paeonia lactiflora Pall.), a perennial herbaceous flower, can grows continuously for approximately 10 years. However, a replanting problem can occur during division propagation which reduces the land use rate and restricts the development of the herbaceous peony industry. We [...] Read more.

The herbaceous peony (Paeonia lactiflora Pall.), a perennial herbaceous flower, can grows continuously for approximately 10 years. However, a replanting problem can occur during division propagation which reduces the land use rate and restricts the development of the herbaceous peony industry. We investigated microbial community changes and soil chemical properties in herbaceous peony soils during different growing and replanting years. The results indicated that the flowering rate, plant height, stem diameter, and leaf area of replanted herbaceous peony were lower, and decreased gradually with increasing replanting years. Compared with the soil after replanting herbaceous peony for one year, soil pH, nutrient contents (AN, AP, AK, and OM), enzyme activities (Inv, Ure, Pho, and Cat), diversity and richness of fungal and bacterial communities decreased after replanting for five years. Long-term replanting increased the relative abundance of harmful soil microorganisms (e.g., Gibberella), and reduced that of beneficial microorganisms (e.g., Bacillus). Overall, after the long-term replanting of herbaceous peony, the soil environment deteriorated, and the soil microbial community structure changed, resulting in the imbalance of soil microecology, damaging the normal growth of herbaceous peony. Full article

(This article belongs to the Special Issue Advances in Ornamental Plant Cultivation and Physiology)

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17 pages, 2495 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Light Intensity during Green-Leaf Butterhead Lettuce Propagation Influences Yield and Carotenoids at Harvest

by Spencer R. Givens, Dustin S. Del Moro, Sarah E. Parker, Alexander G. Renny, Carl E. Sams and Kellie J. Walters

Horticulturae 2023, 9(2), 223; https://doi.org/10.3390/horticulturae9020223 - 7 Feb 2023

Cited by 2 | Viewed by 1782

Abstract

Controlled environment agriculture (CEA) operations must increase resource-use efficiency, yield, and phytonutrient concentrations to remain competitive. Carotenoids are phytonutrients of interest due to their purported health promoting effects. Their content is impacted by environmental controls, including lighting. Light-use efficiency increases with greater planting [...] Read more.

Controlled environment agriculture (CEA) operations must increase resource-use efficiency, yield, and phytonutrient concentrations to remain competitive. Carotenoids are phytonutrients of interest due to their purported health promoting effects. Their content is impacted by environmental controls, including lighting. Light-use efficiency increases with greater planting density, which is highest during seedling production. This creates the opportunity to raise light intensity during seedling production to improve growth characteristics and phytonutrient concentrations at harvest. Therefore, the objective of this research was to quantify the extent to which light intensity influences carotenoid accumulation in green butterhead lettuce seedlings, and if differences remain at harvest. Lettuce ‘Rex’ (Lactuca sativa L.) seedlings were grown under fluorescent lighting with intensities of 60, 100, 200, 400, or 600 µmol·m⁻²·s⁻¹ with a 24-h photoperiod. After 14 days, seedlings were transplanted into raft hydroponic systems in a common greenhouse environment and grown for 21 days. At transplant and final harvest, tissue samples were collected and stored at −80 °C for phytonutrient analysis. Carotenoids, β-carotene, lutein, neoxanthin, zeaxanthin, and violaxanthin, and chlorophylls a and b were quantified using high-performance liquid chromatography (HPLC). We observed a 475% fresh mass enhancement in seedlings grown under 400 versus 60 µmol·m⁻²·s⁻¹, with a 174% improvement persisting to final harvest. Higher seedling light intensities also generally increased leaf numbers in seedlings and at final harvest, as well as seedling carotenoid concentrations. Final harvest carotenoid concentrations generally decreased with increasing light intensity. Thus, producers should be cognizant that seedling light intensity strongly influences seedling and finished production yield, morphology, and carotenoid content. Full article

(This article belongs to the Special Issue Controlled Environment Horticulture: Latest Advances and Future Prospects)

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12 pages, 5984 KiB

Open AccessEditor’s ChoiceArticle

Anatomical and Chemical Analysis of Moringa oleifera Stem Tissue Grown under Controlled Conditions

by Holly M. McVea and Lisa J. Wood

Horticulturae 2023, 9(2), 213; https://doi.org/10.3390/horticulturae9020213 - 6 Feb 2023

Viewed by 3231

Abstract

Moringa oleifera is a relatively well-studied ethnobotanical species, but information is limited regarding its stem anatomy and the production potential of phytochemicals from bark tissue. Knowing that variation exists in the production of chemical defenses by plants with growing conditions and with developmental stages, [...] Read more.

Moringa oleifera is a relatively well-studied ethnobotanical species, but information is limited regarding its stem anatomy and the production potential of phytochemicals from bark tissue. Knowing that variation exists in the production of chemical defenses by plants with growing conditions and with developmental stages, M. oleifera was grown under controlled conditions to characterize stem tissues and to determine if stem bark contained the correct phytochemical compounds to be of value in medicinal treatments. We used microscopy to characterize the stem anatomy of M. oleifera and analyzed stem bark extracts using FTIR and GC to identify 4-(α-L-rhamnosyloxy)-benzyl isothiocyanate (moringin) and benzylamine (moringine) in tissue. We found the stems to be in transition between juvenile and mature stages of development at 4 months old under the growth conditions used. In 7-month-old stems, we found the presence of moringin in all bark samples and did not find any moringine. These results indicate that M. oleifera bark of 7-month-old trees grown in greenhouse conditions may be valuable for drug development. Full article

(This article belongs to the Special Issue Morphology, Palynology and Phytochemicals of Medicinal Plants)

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11 pages, 3982 KiB

Open AccessEditor’s ChoiceArticle

Preharvest UV-B Treatment Improves Strawberry Quality and Extends Shelf Life

by Xudong Zhu, Frances Trouth and Tianbao Yang

Horticulturae 2023, 9(2), 211; https://doi.org/10.3390/horticulturae9020211 - 5 Feb 2023

Cited by 3 | Viewed by 2116

Abstract

Postharvest ultraviolet B (UV-B) radiation has been used to control pathogen incidence on fresh produce, but little attention has been paid to preharvest UV-B effect on strawberry fruit quality and storage. In this study, strawberry (Fragaria × ananassa Duch. cv Albion) plants [...] Read more.

Postharvest ultraviolet B (UV-B) radiation has been used to control pathogen incidence on fresh produce, but little attention has been paid to preharvest UV-B effect on strawberry fruit quality and storage. In this study, strawberry (Fragaria × ananassa Duch. cv Albion) plants grown in greenhouse were irradiated with UV-B lamps with an intensity of 0.7362 J/s m² for 1 and 2 h every day from 5–7 pm after flowering. Fruits were harvested at red stage for quality evaluation. The results indicated that the preharvest UV-B-treated fruits had lighter color (increased L*) than the control. Total soluble solids (TSS), total phenolics content (TPS) and total anthocyanin content (TAC) of UV-B-treated fruits were higher than for the control fruits. There were no significant differences in any of the quality traits between UV-B one-hour and two-hour treatments. We further evaluated the fruit quality when stored at 5 °C on day 7 and day 14. Compared to untreated control, UV-B-treated fruits retarded decrease in L*, TSS, TPS, TAC and firmness, and reduced fruit decay. Examination of expression of genes related to UV-B signaling indicated that HY5 was the major component of UV-B signaling during the green and white stages. However, anthocyanin genes were highly responsive to UV-B treatment during the red stage. Our results suggest that utilization of a low dose of UV-B radiation during the growth stage can improve strawberry fruit quality, and extend shelf life. This research facilitates the utilization of preharvest UV-B treatment for improving fruit quality in controlled environment agriculture. Full article

(This article belongs to the Collection New Advances in Fruit Quality: Pre-harvest Techniques and Postharvest Management)

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14 pages, 1306 KiB

Open AccessEditor’s ChoiceArticle

Non-Thermal Plasma and Soilless Nutrient Solution Application: Effects on Nutrient Film Technique Lettuce Cultivation

by Carlo Nicoletto, Valentina Falcioni, Silvia Locatelli and Paolo Sambo

Horticulturae 2023, 9(2), 208; https://doi.org/10.3390/horticulturae9020208 - 4 Feb 2023

Cited by 1 | Viewed by 1884

Abstract

Soilless cultivation is one of the best examples of the sustainable intensification concept due to the high use efficiency of its inputs. Managing the nutrient solution through a closed cycle system represents a crucial objective to be pursued, but the recovery of the [...] Read more.

Soilless cultivation is one of the best examples of the sustainable intensification concept due to the high use efficiency of its inputs. Managing the nutrient solution through a closed cycle system represents a crucial objective to be pursued, but the recovery of the nutrient solution requires chemical correction and sanitization. The application of non-thermal plasma (NTP) in agriculture promotes the safety of the nutrient solution, decreasing the use of chemicals. The aim of this study was to evaluate the effects of cold plasma on the nutrient depletion, yield, and qualitative traits of lettuce. A closed soilless system (nutrient film technique) was used to compare different NTP treatments: control, low ionization (LI), and high ionization (HI) in two successive lettuce cycles. No significant differences within the nutrient depletion trends were observed. The treated lettuce’s yield was 12% higher than that of the control, characterized by a higher total soluble solid content and a significantly higher electrical conductivity and titratable acidity than the control. The ion content was higher in HI plants, as were the contents of nitrogen, phosphorous, and potassium. In HI plants, the leaf pigments were higher, but no significant changes were observed for the antioxidant content. Cold plasma is a promising strategy that brings benefits to the crop. Full article

(This article belongs to the Special Issue Advanced of Horticulture Innovative Irrigation Technologies)

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11 pages, 1339 KiB

Open AccessEditor’s ChoiceArticle

Leafy Vegetables’ Agronomic Variables, Nitrate, and Bioactive Compounds Have Different Responses to Bokashi, Mineral Fertilization, and Boiled Chicken Manure

by Fernando Teruhiko Hata, Diego Contiero da Silva, Natália Norika Yassunaka-Hata, Mariana Assis de Queiroz Cancian, Isabella Accorsi Sanches, Caio Eduardo Pelizaro Poças, Maurício Ursi Ventura, Wilma Aparecida Spinosa and Rogério Barbosa Macedo

Horticulturae 2023, 9(2), 194; https://doi.org/10.3390/horticulturae9020194 - 2 Feb 2023

Cited by 2 | Viewed by 1691

Abstract

In the current study, the effect of boiled chicken manure (BCM) doses by fertigation, bokashi, and mineral fertilization on the agronomic variables, bioactive compounds, and nitrate levels of two cultivars of lettuce (romaine and frisée types) and one cultivar of radicchio chicory was [...] Read more.

In the current study, the effect of boiled chicken manure (BCM) doses by fertigation, bokashi, and mineral fertilization on the agronomic variables, bioactive compounds, and nitrate levels of two cultivars of lettuce (romaine and frisée types) and one cultivar of radicchio chicory was studied. Overall, higher agronomic variable values were found for the leafy plants in bokashi-fertilized plants. The BCM 5, 7.5, and 10% fertilization, in general, increased these variables in an apparent increasing trend. For chicory, bokashi presented higher means in comparison with BCM for TB, CB, and CI. For frisée lettuce, bokashi had the highest values for TB, CB, and PH. For romaine, bokashi presented the highest means for all the variables, except for PD. For bioactive compounds, each plant species responded differently when varying the fertilization source. For the nitrate content, higher values were observed in the bokashi and mineral treatments. Full article

(This article belongs to the Special Issue Sustainable and Organic Farming of Vegetable Crops in Greenhouse and Open Field Systems)

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16 pages, 4369 KiB

Open AccessEditor’s ChoiceArticle

Improved Annotation of the Peach (Prunus persica) Genome and Identification of Tissue- or Development Stage-Specific Alternative Splicing through the Integration of Iso-Seq and RNA-Seq Data

by Hui Zhou, Yu Sheng, Keli Qiu, Fei Ren, Pei Shi, Qingmei Xie, Jiying Guo, Haifa Pan and Jinyun Zhang

Horticulturae 2023, 9(2), 175; https://doi.org/10.3390/horticulturae9020175 - 30 Jan 2023

Cited by 1 | Viewed by 1886

Abstract

Alternative splicing (AS) is an important way to generate notable regulatory and proteomic complexity in eukaryotes. However, accurate full-length splicing isoform discovery by second-generation sequencing (SGS) technologies is beset with the precise assembly of multiple isoforms from the same gene loci. In recent [...] Read more.

Alternative splicing (AS) is an important way to generate notable regulatory and proteomic complexity in eukaryotes. However, accurate full-length splicing isoform discovery by second-generation sequencing (SGS) technologies is beset with the precise assembly of multiple isoforms from the same gene loci. In recent years, third-generation sequencing (TGS) technologies have been adopted to gain insight into different aspects of transcriptome complexity, such as complete sequences of mRNA, alternative splicing, fusion transcript, and alternative polyadenylation (APA). Here, we combined PacBio Iso-Seq and Illumina RNA-Seq technologies to decipher the full-length transcriptome of peach. In total, 40,477 nonredundant high-quality consensus transcript sequences were obtained from equally pooled libraries from 10 samples of 6 organs, including leaf, shoot, flower, fruit peel, fruit mesocarp, and fruit stone, of which 18,274 isoforms were novel isoforms of known genes and 546 isoforms were novel gene transcripts. We also discovered 148 fusion transcripts, 15,434 AS events, 508 potential lncRNAs, and 4368 genes with APA events. Of these AS events, the most abundant (62.48%) AS type was intron retention (IR). Moreover, the expression levels of different isoforms identified in this study were quantitatively evaluated, and highly tissue- or development stage-specific expression patterns were observed. The novel transcript isoforms and new characteristics of the peach transcriptome revealed by this study will facilitate the annotation of the peach genome and lay the foundations for functional research in the future. Full article

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

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15 pages, 1225 KiB

Open AccessEditor’s ChoiceArticle

The Parasitoid Hyposoter didymator Can Transmit a Broad Host Range Baculovirus in a Two Host System

by Ariel Morel, Brendan Leigh, Delia Muñoz, Primitivo Caballero, Pilar Medina and Beatriz Dáder

Horticulturae 2023, 9(2), 170; https://doi.org/10.3390/horticulturae9020170 - 28 Jan 2023

Cited by 1 | Viewed by 1630

Abstract

Hyposoter didymator (Thunberg) (Hymenoptera: Ichneumonidae) and baculovirus (BV) might be used jointly to provide effective control of the Spodoptera genus. The literature has mostly covered the safe compatibility between natural enemies and BV-based insecticides, but research on the potential dispersal of BV by [...] Read more.

Hyposoter didymator (Thunberg) (Hymenoptera: Ichneumonidae) and baculovirus (BV) might be used jointly to provide effective control of the Spodoptera genus. The literature has mostly covered the safe compatibility between natural enemies and BV-based insecticides, but research on the potential dispersal of BV by natural enemies is lacking. Thus, the goal of this manuscript was to ascertain if H. didymator was able to disperse the broad host range of Autographa californica nucleopolyhedrovirus (AcMNPV) to Spodoptera littoralis and Spodoptera exigua in choice and non-choice conditions and whether the preference of the parasitoid by one of these noctuids could mediate this dispersion. It was previously needed to improve the rearing of the parasitoid in the laboratory, concerning the optimal host age and length of parasitization, parasitoid competition, and influence of parasitization on the longevity of females. The best rearing conditions for S. littoralis are collective parasitization of mature L3 larvae for 24 h, after at least one day of copulation. Hyposoter didymator transmits AcMNPV to both lepidopterans, but its efficiency is mediated by host preference and the pathogenicity of the BV in each host. In this particular case, H. didymator as well as AcMNPV showed a clear preference towards S. exigua. Full article

(This article belongs to the Collection Non-Chemical Strategies for IPM in Horticulture)

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10 pages, 1550 KiB

Open AccessEditor’s ChoiceArticle

Effect of Low R:FR Ratio on Nitrogen Assimilation and NRT Gene Expression in Pakchoi under Excessive Nitrate Stress

by Xiaoting Zhou, Yirong Gan, Chenxiang Jiang, Qiang Chen, Xu Chen, Libang Chen and Zhongqun He

Horticulturae 2023, 9(2), 159; https://doi.org/10.3390/horticulturae9020159 - 27 Jan 2023

Cited by 1 | Viewed by 1335

Abstract

Nitrate accumulation is a major factor for the secondary salinization of greenhouse soil in China. Our previous study pointed out that a low ratio of red:far-red light (R:FR) can improve salt tolerance in pakchoi under excessive nitrate stress. However, the nitrogen metabolism mechanism [...] Read more.

Nitrate accumulation is a major factor for the secondary salinization of greenhouse soil in China. Our previous study pointed out that a low ratio of red:far-red light (R:FR) can improve salt tolerance in pakchoi under excessive nitrate stress. However, the nitrogen metabolism mechanism is still unclear. To detect the effect of a low R:FR ratio on nitrogen metabolism of pakchoi under excessive nitrate stress, two extra additions of nitrogen of 80 mmol·L⁻¹ NO₃⁻ (H80) and 160 mmol·L⁻¹ NO₃⁻ (H160) with/without a low R:FR ratio (R:FR = 0.7) were set, and the growth index, chlorophyll content, key enzymes in nitrogen metabolism, nitrate and glutamic acid content and NRT gene expression level of pakchoi leaves were examined. The results indicated that a low ratio of R:FR could alleviate the reduction in growth and chlorophyll content in pakchoi under high-level nitrogen stress (H80 and H160). The activity of nitrate reductase (NR), glutamine synthetase (GS) and glutamine synthetase (GOGAT) decreased under H80 and H160 conditions, except of NR with the H80 treatment. The activity of glutamate dehydrogenase (GDH) increased under H80 treatment, but decreased under H160 treatment. However, the activity of GDH decreased further by reducing the ratio of R:FR. Excessive nitrate stress increased the nitrate content, and a low R:FR ratio could inhibit nitrate accumulation. However, the change in glutamic acid content was significantly increased under a low R:FR ratio without stress. Under the high-nitrogen level treatment (H160), the use of a low ratio of R:FR increased NRT gene expression. Therefore, a low R:FR ratio (R:FR = 0.7) could effectively promote the growth of pakchoi and improve its nitrogen metabolism, thus alleviating the stress effect of a high level of nitrogen in pakchoi. Full article

(This article belongs to the Special Issue LED Lighting in Vegetable Crops)

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20 pages, 5888 KiB

Open AccessEditor’s ChoiceArticle

Understanding Particulate Matter Retention and Wash-Off during Rainfall in Relation to Leaf Traits of Urban Forest Tree Species

by Myeong Ja Kwak, Jongkyu Lee, Sanghee Park, Yea Ji Lim, Handong Kim, Su Gyeong Jeong, Joung-a Son, Sun Mi Je, Hanna Chang, Chang-Young Oh, Kyongha Kim and Su Young Woo

Horticulturae 2023, 9(2), 165; https://doi.org/10.3390/horticulturae9020165 - 27 Jan 2023

Cited by 8 | Viewed by 1751

Abstract

Dynamic particulate matter (PM) behavior on leaves depends on rainfall events, leaf structural and physical properties, and individual tree crowns in urban forests. To address this dependency, we compared the observed relationships between PM wash-off ability and leaf traits on inner and outer [...] Read more.

Dynamic particulate matter (PM) behavior on leaves depends on rainfall events, leaf structural and physical properties, and individual tree crowns in urban forests. To address this dependency, we compared the observed relationships between PM wash-off ability and leaf traits on inner and outer crown-positioned leaves during rainfall events. Data showed significant differences in the PM wash-off ability between inner and outer crown-positioned leaves relative to rainfall events due to leaf macro- and micro-structure and geometric properties among tree species. Our results showed that PM wash-off effects on leaf surfaces were negatively associated with trichome density and size of leaf micro-scale during rainfall events. Specifically, Quercus acutissima with dense trichomes and micro-level surface roughness with narrow grooves on leaf surfaces showed lower total PM wash-off in both inner (−38%) and outer (105%) crowns during rainfall. Thus, their rough leaves in the inner crown might newly capture and/or retain more PM than smooth leaves even under rainfall conditions. More importantly, Euonymus japonicus, with a thin film-like wax coverage without trichome, led to higher total PM wash-off in both inner (368%) and outer (629%) crowns during rainfall. Furthermore, we studied the changes in PM wash-off during rainfall events by comparing particle size fractions, revealing a very significant association with macro-scale, micro-scale, and geometric features. Full article

(This article belongs to the Special Issue Responses to Environmental Stress in Ornamental Plants/Horticultural Plants)

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12 pages, 1041 KiB

Open AccessEditor’s ChoiceArticle

Determination of Selenium Speciation in High Se-Enriched Edible Fungus Ganoderma lucidum Via Sequential Extraction

by Wenyao Shi, Yuzhu Hou, Zezhou Zhang, Xuebin Yin, Xiaohu Zhao and Linxi Yuan

Horticulturae 2023, 9(2), 161; https://doi.org/10.3390/horticulturae9020161 - 27 Jan 2023

Cited by 3 | Viewed by 1362

Abstract

Edible fungi are often used as an important selenium (Se) source to improve human daily Se intakes as food or Se supplements because of their strong ability to accumulate Se, in which Ganoderma lucidum was widely accepted in China. However, the existing Se [...] Read more.

Edible fungi are often used as an important selenium (Se) source to improve human daily Se intakes as food or Se supplements because of their strong ability to accumulate Se, in which Ganoderma lucidum was widely accepted in China. However, the existing Se speciation analysis methods such as protease K-based or trypsin-protease XIV-based, have low extraction rate and enzymatic hydrolysis rate (<30%) on the Se-enriched edible fungi, resulting that it is impossible to effectively evaluate Se transformation and safety of Se-enriched edible fungi. In order to improve the extraction rate and enzymatic hydrolysis rates, 12 extraction methods (combination of buffer solutions and enzymes) including 4 two-step extraction methods and 8 three-step extraction methods were applied to extract Se from high Se-enriched Ganoderma lucidum (Total Se content 245.7 μg/g in dry matter (DW)) in the present study. The results displayed that one three-step sequential extraction method as aqueous solution extraction-pepsin extraction-trypsin extraction performed the best, by which the total Se extraction rate could reach 65%, the total Se enzyme hydrolysis rate was 40%, and the Se speciation was revealed as Selenite (63.6%), SeCys₂ (20.1%), SeMeCys (14.8%) and SeMet (1.5%) in this high Se-enriched Ganoderma lucidum. This study offers a reliable and efficient method to evaluate the Se transformation and the Se safety in high Se-enriched edible fungi. Full article

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12 pages, 2800 KiB

Open AccessEditor’s ChoiceArticle

Studies on the Identification of Resistance to Fusarium oxysporum (Schlecht.) in Different Genetic Backgrounds of Asparagus officinalis (L.) and Its Defense Responses

by Julia Jacobi, Holger Budahn, Thomas Nothnagel and Janine König

Horticulturae 2023, 9(2), 158; https://doi.org/10.3390/horticulturae9020158 - 27 Jan 2023

Cited by 4 | Viewed by 1791

Abstract

Due to the restricted genetic diversity among current asparagus cultivars, wild relatives are of particular interest as a source of resistance. In this study, seventeen cultivars and wild relatives were tested for their resistance to Fusarium oxysporum in the seedling test. Two isolates [...] Read more.

Due to the restricted genetic diversity among current asparagus cultivars, wild relatives are of particular interest as a source of resistance. In this study, seventeen cultivars and wild relatives were tested for their resistance to Fusarium oxysporum in the seedling test. Two isolates differing in virulence (single spore lines with high and low virulence) were used for testing. Most of the tested genotypes showed high infestation, whereby Asparagus aethiopicus caused no browning of the roots or growth depression. This wild relative was evaluated for its defence response after infection with F. oxysporum. For comparison, the wild relative Asparagus densiflorus and Asparagus officinalis cv. Thielim were tested. Like A. densiflorus, A. aethiopicus showed accumulation of hydrogen peroxide as a defence mechanism, while Asparagus officinalis cv. Thielim showed no storage of hydrogen compounds. Full article

(This article belongs to the Special Issue Advances in Asparagus Production, Genomics and Breeding)

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19 pages, 2613 KiB

Open AccessEditor’s ChoiceArticle

Tomato Leaf Disease Classification via Compact Convolutional Neural Networks with Transfer Learning and Feature Selection

by Omneya Attallah

Horticulturae 2023, 9(2), 149; https://doi.org/10.3390/horticulturae9020149 - 22 Jan 2023

Cited by 33 | Viewed by 11658

Abstract

Tomatoes are one of the world’s greatest valuable vegetables and are regarded as the economic pillar of numerous countries. Nevertheless, these harvests remain susceptible to a variety of illnesses which can reduce and destroy the generation of healthy crops, making early and precise [...] Read more.

Tomatoes are one of the world’s greatest valuable vegetables and are regarded as the economic pillar of numerous countries. Nevertheless, these harvests remain susceptible to a variety of illnesses which can reduce and destroy the generation of healthy crops, making early and precise identification of these diseases critical. Therefore, in recent years, numerous studies have utilized deep learning (DL) models for automatic tomato leaf illness identification. However, many of these methods are based on a single DL architecture that needs a high computational ability to update these hyperparameters leading to a rise in the classification complexity. In addition, they extracted large dimensions from these networks which added to the classification complication. Therefore, this study proposes a pipeline for the automatic identification of tomato leaf diseases utilizing three compact convolutional neural networks (CNNs). It employs transfer learning to retrieve deep features out of the final fully connected layer of the CNNs for more condensed and high-level representation. Next, it merges features from the three CNNs to benefit from every CNN structure. Subsequently, it applies a hybrid feature selection approach to select and generate a comprehensive feature set of lower dimensions. Six classifiers are utilized in the tomato leaf illnesses identification procedure. The results indicate that the K-nearest neighbor and support vector machine have attained the highest accuracy of 99.92% and 99.90% using 22 and 24 features only. The experimental results of the proposed pipeline are also compared with previous research studies for tomato leaf diseases classification which verified its competing capacity. Full article

(This article belongs to the Special Issue Smart Horticulture, Plant Secondary Compounds and Their Applications)

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15 pages, 2579 KiB

Open AccessEditor’s ChoiceArticle

Identification of a Monosomic Alien Chromosome Addition Line Responsible for the Purple Color Trait in Heading Chinese Cabbage

by Xiaoyun Xin, Deshuang Zhang, Hong Zhao, Tongbing Su, Xiuyun Zhao, Weihong Wang, Peirong Li, Yangjun Yu, Jiao Wang, Shuancang Yu and Fenglan Zhang

Horticulturae 2023, 9(2), 146; https://doi.org/10.3390/horticulturae9020146 - 21 Jan 2023

Cited by 2 | Viewed by 1663

Abstract

Purple heading Chinese cabbage has become popular in recent years due to its attractive color and health benefits. However, purple varieties remain rare, and the regulation mechanism of anthocyanin accumulation in Chinese cabbage is still largely unknown. By introducing the purple color trait [...] Read more.

Purple heading Chinese cabbage has become popular in recent years due to its attractive color and health benefits. However, purple varieties remain rare, and the regulation mechanism of anthocyanin accumulation in Chinese cabbage is still largely unknown. By introducing the purple color trait from Brassica juncea, a new purple heading Chinese cabbage cultivar (18M-245) was generated with deep purple leaves at both the seedling and adult stages. Anthocyanin accumulation in 18M-245 increased when grown at low temperatures. FISH and genotyping results showed that the purple trait was caused by an alien chromosome addition line derived from the Brassica B genome. The LDOX coding gene BjuB014115 from the addition line was highly expressed in 18M-245, consistent with the results of anthocyanin accumulation. Meanwhile, several MYB and bHLH transcriptional factors from the Brassica A genome were found to directly bind to the promoter of BjuB014115, suggesting that interactions between the Brassica A and B genomes are involved in the regulatory network of anthocyanin biosynthesis in Chinese cabbage. Our results provide new insights into the regulation mechanism of anthocyanin biosynthesis in purple heading Chinese cabbage. Full article

(This article belongs to the Special Issue Advances in Brassica Crops Genomics and Breeding, 2nd Edition)

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14 pages, 7170 KiB

Open AccessEditor’s ChoiceArticle

Morphological and Molecular Identification of Dactylonectria macrodidyma as Causal Agent of a Severe Prunus lusitanica Dieback in Italy

by Susanna Pecchia, Benedetta Caggiano, Daniele Da Lio and Emilio Resta

Horticulturae 2023, 9(2), 145; https://doi.org/10.3390/horticulturae9020145 - 21 Jan 2023

Viewed by 2271

Abstract

During the summer of 2016, severe dieback was observed on young potted Prunus lusitanica (Portugal laurel) plants in a nursery in the Pistoia province (Tuscany, Italy). Cylindrocarpon-like isolates were consistently recovered from diseased plant tissues. The combination of morphological and molecular traits, [...] Read more.

During the summer of 2016, severe dieback was observed on young potted Prunus lusitanica (Portugal laurel) plants in a nursery in the Pistoia province (Tuscany, Italy). Cylindrocarpon-like isolates were consistently recovered from diseased plant tissues. The combination of morphological and molecular traits, including sequence data of histone 3 and β-tubulin genes (HIS3, TUB2) and internal transcribed spacers (ITS), allowed the identification of Dactylonectria macrodidyma (Halleen, Schroers & Crous) L. Lombard & Crous (asexual form Cylindrocarpon macrodidymum) as the causal agent of the disease. Pathogenicity tests reproduced disease symptoms observed in the nursery after six months fulfilling Koch’s postulates. D. macrodidyma is a soilborne plant pathogen and is to be considered of great economic importance on P. lusitanica, especially under favorable conditions such as stress and/or reduction of plant vitality. The increasingly frequent reports of the disease caused by the pathogen in various nurseries suggest that pot cultivation, together with prolonged drought periods, may play a role in favoring infections. To the best of our knowledge, this is the first report worldwide of the occurrence of dieback on Prunus lusitanica caused by D. macrodidyma. Full article

(This article belongs to the Section Plant Pathology and Disease Management (PPDM))

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18 pages, 3725 KiB

Open AccessEditor’s ChoiceArticle

Performance of Wild Tomato Accessions and Elucidation of Resistance against Invasive Pest Phthorimaea absoluta Damage under Tropical Conditions

by Pritha Ghosh, K. S. Jagadish, M. G. Purushothama, Peter Hanson, Mohamed Rakha, Paola Sotelo-Cardona, Sridhar Vaddi and Ramasamy Srinivasan

Horticulturae 2023, 9(2), 143; https://doi.org/10.3390/horticulturae9020143 - 20 Jan 2023

Cited by 1 | Viewed by 1604

Abstract

Invasive tomato leaf miner, Phthorimaea absoluta causes serious damage and yield loss in tomato production in open-field and protected cultivation. Use of chemical pesticides is uneconomical and adversely affects humans and the environment. Host-plant resistance is an effective, economical and eco-friendly alternative to [...] Read more.

Invasive tomato leaf miner, Phthorimaea absoluta causes serious damage and yield loss in tomato production in open-field and protected cultivation. Use of chemical pesticides is uneconomical and adversely affects humans and the environment. Host-plant resistance is an effective, economical and eco-friendly alternative to chemical pesticides. In this study, four wild tomato accessions from the World Vegetable Center along with one susceptible check were evaluated for their antixenosis and antibiosis effects on P. absoluta. The accessions VI037241 (Solanum galapagense) and VI037240 (S. cheesmaniae) were highly resistant, leading to 85% larval mortality under no-choice conditions. Choice assay also showed less oviposition preference and reduced pupal weight. Both VI037241 and VI037240 showed the highest resistance under field conditions. The accessions of S. habrochaites (LA1777) and S. habrochaites var. glabratum (VI030462) demonstrated moderate resistance against P. absoluta. Wild accessions recorded significantly less eggs and leaf damage in field trials compared to the susceptible genotype, S. lycopersicum (CL5915). Trichome density, type and higher production of acylsugar contributed to the insect resistance. Acylsugar production in wild accessions was less during the rainy season but significantly higher than in susceptible genotype. These findings can be useful to develop P. absoluta-resistant tomato varieties in tropics. Full article

(This article belongs to the Special Issue Integrated Pest Management of Fruit Trees and Other Horticultural Crops)

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11 pages, 2165 KiB

Open AccessEditor’s ChoiceArticle

An Economic Method to Identify Cultivars and Elite Lines in Radish (Raphanus sativus L.) for Small Seed Companies and Independent Breeders

by Huiyeon Hong, Junho Lee and Wonbyoung Chae

Horticulturae 2023, 9(2), 140; https://doi.org/10.3390/horticulturae9020140 - 20 Jan 2023

Cited by 4 | Viewed by 1646

Abstract

Radish is a root vegetable crop, and many F₁ cultivars have been developed by exploiting heterosis. Considerable time and resources are required to test the performance and combining ability of F₁ cultivars and parental lines; therefore, economical methods to identify them [...] Read more.

Radish is a root vegetable crop, and many F₁ cultivars have been developed by exploiting heterosis. Considerable time and resources are required to test the performance and combining ability of F₁ cultivars and parental lines; therefore, economical methods to identify them are needed before field tests. This study was conducted to determine the minimum number of markers needed to identify cultivars and elite lines. PCR-based markers were applied to radish cultivars and elite lines and selected based on chromosomal location, polymorphic information content, and allele frequency. The power of selected marker sets to detect genetically similar cultivars or elite lines was confirmed using cultivars with high genetic similarity and elite lines with the same parents. Eleven markers successfully identified not only all 105 radish cultivars tested but also cultivars with high genetic similarity reported in previous studies. Fourteen markers, including the nine among 11 markers for cultivar identification, also successfully distinguished all 115 elite lines tested, including ones with the same parents and separated at F₂–F₆ generations. The markers developed for the identification of radish cultivars and elite lines require only 11 and 14 markers, respectively, and simple PCR and gel electrophoresis instruments. This method is very simple and can be easily applied to other crops. Full article

(This article belongs to the Section Propagation and Seeds)

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11 pages, 826 KiB

Open AccessEditor’s ChoiceArticle

Cladosporium Species: The Predominant Species Present on Raspberries from the U.K. and Spain and Their Ability to Cause Skin and Stigmata Infections

by Lauren Helen Farwell, Greg Deakin, Adrian Lee Harris, Georgina Fagg, Thomas Passey, Carol Verheecke-Vaessen, Naresh Magan and Xiangming Xu

Horticulturae 2023, 9(2), 128; https://doi.org/10.3390/horticulturae9020128 - 17 Jan 2023

Cited by 3 | Viewed by 1894

Abstract

Raspberry (Rosales: Rosaceae) production in the U.K. has moved rapidly in the last 10 years to under polythene, combined with a reduced availability of broad-spectrum fungicides. Hence, the incidence of previously less prevalent diseases, such as Cladosporium (Capnodiales: Cladosporiaceae [...] Read more.

Raspberry (Rosales: Rosaceae) production in the U.K. has moved rapidly in the last 10 years to under polythene, combined with a reduced availability of broad-spectrum fungicides. Hence, the incidence of previously less prevalent diseases, such as Cladosporium (Capnodiales: Cladosporiaceae), has largely increased. This study aimed to identify the predominant Cladosporium species on raspberry and to understand the nature of its infection on raspberry fruit. Raspberries were collected from farms across the U.K. and Spain and incubated; fungal isolates were then isolated from typical Cladosporium lesions and identified to the species level based on the sequences of the trans elongation factor α and actin genes. Cladosporium cladosporioides (Fres) de Vries was confirmed as the predominant species responsible for infecting raspberry fruit close to harvest on fruit from the U.K. and Spain, being present on 41.5% of U.K. fruit and 84.6% of Spanish fruit. Raspberries were subsequently inoculated at different developmental stages with C. cladosporioides isolates to determine the susceptibility to Cladosporium skin lesions and stigmata infections in relation to the developmental stage. Only the ripening and ripe raspberries were susceptible to Cladosporium, resulting in skin lesions. Cladosporium can colonise the stigmata of raspberries earlier in fruit development and future research is required to determine if such stigmata infections could cause subsequent skin lesion infections. This study has provided the necessary epidemiological information to develop effective management measures against the Cladosporium species. Full article

(This article belongs to the Special Issue Integrated Pest Management in Horticulture)

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15 pages, 3336 KiB

Open AccessEditor’s ChoiceArticle

Effect of Red and Blue Light on Cucumber Seedlings Grown in a Plant Factory

by Dezhi Jin, Xiaofeng Su, Yuefeng Li, Mingming Shi, Bobo Yang, Wenchang Wan, Xing Wen, Shaojun Yang, Xiaotao Ding and Jun Zou

Horticulturae 2023, 9(2), 124; https://doi.org/10.3390/horticulturae9020124 - 17 Jan 2023

Cited by 12 | Viewed by 6365

Abstract

Light-emitting diodes (LEDs) have been regarded as the best artificial source of light for a plant factory. However, the effect of light quality on seedling production in such environments requires further study. On the basis of the practical application of light on cucumber [...] Read more.

Light-emitting diodes (LEDs) have been regarded as the best artificial source of light for a plant factory. However, the effect of light quality on seedling production in such environments requires further study. On the basis of the practical application of light on cucumber seedlings (Ansha Company) in plant factories, the present investigation tracked and recorded the specific effects of red and blue light on the growth of the seedlings by analyzing the photo-biological mechanism involved. The growth parameters, as well as the photosynthetic characteristics of cucumber seedlings, were measured at different variations of light quality. The results showed that when the proportion of red light in the light source was higher than blue light, the height of the seedlings, leaf size, stem diameter, Dixon Quality Index (DQI), relative chlorophyll content, and the net photosynthetic rate were higher than those of the experimental group with a relatively high proportion of blue light. In the case of R7B3 (70% red light and 30% blue light), the stem diameter, DQI, and net photosynthetic rate of seedlings were 14%, 57%, and 22% higher than the minimum value, respectively. The present study analyzed the influence of red and blue light on plant growth characteristics during actual production and provides standardization for it. Full article

(This article belongs to the Special Issue LED Lighting in Vegetable Crops)

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16 pages, 1751 KiB

Open AccessEditor’s ChoiceArticle

Hormone–Flavonoid Patterns in Two Genotypes of Campanula portenschlagiana with Distinct Adventitious Rooting Competence

by Tábata Bergonci, Inge S. Fomsgaard, Katrine H. Kjaer and Ivan A. Paponov

Horticulturae 2023, 9(1), 121; https://doi.org/10.3390/horticulturae9010121 - 16 Jan 2023

Cited by 1 | Viewed by 1641

Abstract

In horticulture and floriculture, plants are predominantly propagated vegetatively from stem cuttings. Consequently, the success of propagation depends on a plant’s capacity to form adventitious roots (AR) at the basal part of the cutting, and AR formation depends on the interaction between flavonoids [...] Read more.

In horticulture and floriculture, plants are predominantly propagated vegetatively from stem cuttings. Consequently, the success of propagation depends on a plant’s capacity to form adventitious roots (AR) at the basal part of the cutting, and AR formation depends on the interaction between flavonoids and plant hormones in the basal part. In ornamental plants, flavonoid accumulation is important for flower color and can interact with plant hormone activity. In this study, we used an aeroponic system to culture two Campanula portenschlagiana genotypes contrasting in flower color to estimate cultivar differences in AR formation, flavonoid concentrations, and hormone composition. We found a greater accumulation of flavonols and flavones in petals in a blue-flowered genotype than in a white-flowered genotype. The blue-flowered genotype also accumulated more flavonols and flavones in the basal part of cuttings and showed better AR formation. The better AR formation in the blue-colored genotype was related to a greater accumulation of auxin and a lower accumulation of ABA in the basal part of the cuttings. In conclusion, higher flavonoid levels in the basal part of cuttings may interact with hormone action to affect excision-induced AR formation during the vegetative propagation of Campanula. Full article

(This article belongs to the Section Propagation and Seeds)

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17 pages, 983 KiB

Open AccessEditor’s ChoiceReview

The Role of 1-methylcyclopropylene (1-MCP) and Salicylic Acid (SA) in Induced Resistance of Postharvest Fruits

by Xiangzhi Meng, Jiazhen Fang, Maorun Fu, Wenxiao Jiao, Pengfei Ren and Xiaoying Yang

Horticulturae 2023, 9(1), 108; https://doi.org/10.3390/horticulturae9010108 - 13 Jan 2023

Cited by 6 | Viewed by 2769

Abstract

Postharvest diseases cause huge postharvest losses of horticultural fresh produce. Cooling and synthetic fungicide are used as traditional postharvest preservation technology. Recently, induced resistance has been thought to be an optional and perhaps alternative preservation technology. 1-methylcyclopropylene (1-MCP) and salicylic acid (SA) are [...] Read more.

Postharvest diseases cause huge postharvest losses of horticultural fresh produce. Cooling and synthetic fungicide are used as traditional postharvest preservation technology. Recently, induced resistance has been thought to be an optional and perhaps alternative preservation technology. 1-methylcyclopropylene (1-MCP) and salicylic acid (SA) are two more common chemical agents used mostly as a preservative for harvested fruit in order to achieve better quality and better taste. Many reports have also proven that 1-MCP and SA could induce postharvest fruit resistance. The purpose of this review is to summarize the role of 1-MCP and SA in postharvest fruit resistance, including the effect of 1-MCP and SA on the induced resistance as well as its involved mechanism; the effects of 1-MCP and SA on firmness, phenolic metabolism, membrane lipid metabolism, and reactive oxygen species in fruit after harvest; and the effects of 1-MCP and SA on disease resistance-related defense enzymes, proteins, signaling synthesis, and signaling pathways as well as the combined effect of 1-MCP and SA on the induced resistance and its mechanism. Meanwhile, we prospect for the future direction of increasing postharvest fruit resistance by 1-MCP and SA in more depth. Full article

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

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13 pages, 1567 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Selection Progress for Resistance to Fusarium Basal Rot in Short-Day Onions Using Artificial Inoculation Mature Bulb Screening

by Suman Sharma and Christopher S. Cramer

Horticulturae 2023, 9(1), 99; https://doi.org/10.3390/horticulturae9010099 - 12 Jan 2023

Cited by 6 | Viewed by 2508

Abstract

Fusarium basal rot (FBR), caused by a soil-borne fungus, Fusarium oxysporum f. sp. cepae (FOC), is a major disease hindering onion production worldwide. This study was conducted to evaluate the initial and the most advanced selected populations of seven open-pollinated short-day onion cultivars [...] Read more.

Fusarium basal rot (FBR), caused by a soil-borne fungus, Fusarium oxysporum f. sp. cepae (FOC), is a major disease hindering onion production worldwide. This study was conducted to evaluate the initial and the most advanced selected populations of seven open-pollinated short-day onion cultivars for FBR susceptibility, along with two check cultivars using the conidial inoculation of mature bulbs for two consecutive years. The artificial inoculation of mature bulbs was carried out by applying a virulent FOC isolate ‘CSC 515’ at a final concentration of 3.0 × 10⁴ spores mL⁻¹ to the transversely cut basal plates of onion bulbs. The basal plates of 20 arbitrarily chosen bulbs per plot were recut after 20 days of incubation and then were rated for FBR severity using a rating scale of 1 (no disease) to 9 (≥70% of the basal plate is infected). The bulbs with a rating of 1 were saved and then bulked to form the seeds for the next generation. The selected populations exhibited a variable response for FBR severity when evaluated over two years, with an improvement in the most advanced selections observed for a majority of the cultivars. For example, the advanced selections of ‘NuMex Sweetpak’ exceeded the partially resistant check ‘Serrana’ in their levels of resistance when both were evaluated in the second year. A conidial inoculation can be effective in the development of FBR-resistant cultivars. In addition, this inoculation method can accelerate breeding efforts by determining the genetic mechanism(s) responsible for FBR resistance, locating quantitative trait loci, and facilitating marker-assisted selection. Full article

(This article belongs to the Special Issue Advances in Allium Breeding and Genetics, Volume II)

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15 pages, 5987 KiB

Open AccessEditor’s ChoiceArticle

Seasonal Development of Paeonia obovata and Paeonia oreogeton and Their Contents of Biologically Active and Reserve Substances in the Forest-Steppe Zone of Western Siberia

by Olga V. Kalendar, Vera A. Kostikova, Tatiana A. Kukushkina, Andrey S. Erst, Alexander A. Kuznetsov, Maxim S. Kulikovskiy and Olga Y. Vasilyeva

Horticulturae 2023, 9(1), 102; https://doi.org/10.3390/horticulturae9010102 - 12 Jan 2023

Cited by 1 | Viewed by 1330

Abstract

Paeonia obovata and Paeonia oreogeton belong to the monotypic family Paeoniaceae. Both are popular as ornamental plants. P. obovata and P. oreogeton have been introduced into Novosibirsk Oblast (Western Siberia) from Primorye (Far East). The aim of the study was to assess their [...] Read more.

Paeonia obovata and Paeonia oreogeton belong to the monotypic family Paeoniaceae. Both are popular as ornamental plants. P. obovata and P. oreogeton have been introduced into Novosibirsk Oblast (Western Siberia) from Primorye (Far East). The aim of the study was to assess their adaptability as well as the effect of seasonal developmental stages on the accumulation of secondary metabolites and reserve substances in the leaves and rhizomes under the conditions of Akademgorodok (Novosibirsk, Russia). According to long-term data (15 years), P. obovata and P. oreogeton complete the entire growth cycle here, including flowering and fruiting. Both species exhibited abundant flowering, but in the first 3 years, P. oreogeton did not bloom; yet under the microclimatic conditions specifically selected for this species (a more shaded area), it started to bloom and fruit yearly. A biochemical analysis (by spectrometric method) of P. obovata and P. oreogeton grown in Akademgorodok showed that the leaves accumulate higher concentrations of flavonols (P. obovata: 1.77%), tannins (P. oreogeton: 16.42%), ascorbic acid (P. oreogeton: 155.2 mg/100 g), and sugars (P. obovata: 20.85%) as compared to the roots. Peony rhizomes contain higher concentrations of protopectins (P. oreogeton: 13.03%), saponins (P. obovata: 21.06%), and starch (P. obovata: 30.20%) than the leaves do. These data can help to increase the levels of these natural compounds in these species. Further investigation into the dynamics of accumulation of biologically active substances in the organs of peonies will help to identify introduced plant species having high biochemical potential for the pharmaceutical industry. Full article

(This article belongs to the Special Issue Morphology, Palynology and Phytochemicals of Medicinal Plants)

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13 pages, 6930 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Growth and Photosynthetic Rate of Cucumber Seedlings Affected by Far-Red Light Using a Semi-Open Chamber and Imaging System

by Yu Hyun Moon, Myongkyoon Yang, Ui Jeong Woo, Ha Seon Sim, Tae Yeon Lee, Ha Rang Shin, Jung Su Jo and Sung Kyeom Kim

Horticulturae 2023, 9(1), 98; https://doi.org/10.3390/horticulturae9010098 - 12 Jan 2023

Cited by 4 | Viewed by 1799

Abstract

Far-red light was excluded in photosynthetic photon flux; however, recent studies have shown that it increases photosynthetic capacity. In addition, there were few studies on the whole canopy photosynthetic rate and continuous changes of morphology on cucumber seedlings affected by far-red light. This [...] Read more.

Far-red light was excluded in photosynthetic photon flux; however, recent studies have shown that it increases photosynthetic capacity. In addition, there were few studies on the whole canopy photosynthetic rate and continuous changes of morphology on cucumber seedlings affected by far-red light. This study evaluated the effect of conventional white LEDs adding far-red light on cucumber seedlings using a semi-open chamber system for the measurement of the whole canopy gas exchange rate, and the Raspberry Pi-based imaging system for the analysis of a continuous image. In the image, through the imaging system, it was confirmed that far-red light promoted the germination rate of cucumber seedlings and enhanced early growth. However, the dry weight of the shoot and root did not increase. The measured net apparent CO₂ assimilation rate was improved by an increasing leaf area during the cultivation period. The conventional white LED light source with added far-red light increased the photosynthetic rate of cucumber seedlings’ whole canopy. However, at the early seedling stage, plant height and leaf area of the whole canopy was increased by far-red light, and it was revealed that the image data saturated faster. It was considered that the photosynthetic efficiency decreased due to a shading effect of the limited planting density of the cell tray. The results found that using appropriate far-red light, considering planting density, could increase the photosynthetic rate of the whole canopy of crops, thereby promoting crop growth, but it was judged that the use of far-red light in the early growth stage of cucumber seedlings should be considered carefully. Full article

(This article belongs to the Section Vegetable Production Systems)

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15 pages, 1050 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Coir-Based Growing Media with Municipal Compost and Biochar and Their Impacts on Growth and Some Quality Parameters in Lettuce Seedlings

by Tiago Carreira Martins, Rui M. A. Machado, Isabel Alves-Pereira, Rui Ferreira and Nazim S. Gruda

Horticulturae 2023, 9(1), 105; https://doi.org/10.3390/horticulturae9010105 - 12 Jan 2023

Cited by 7 | Viewed by 2808

Abstract

The purpose of this study was to develop substrates with little or no peat by combining coir-based growing media with municipal compost and/or acacia biochar, two locally produced renewable resources, and to assess their effects on lettuce seedling emergence and growth, as well [...] Read more.

The purpose of this study was to develop substrates with little or no peat by combining coir-based growing media with municipal compost and/or acacia biochar, two locally produced renewable resources, and to assess their effects on lettuce seedling emergence and growth, as well as their content in photosynthetic pigments and total phenols. Two experiments were carried out, the first with six mixes using compost and biochar blended with perlite, pine bark, and blonde peat to adjust some physicochemical characteristics. The mixes of coir: compost: pine bark: blonde peat (73:12:5:10, v/v) and coir: compost: biochar: blonde peat (73:12:10:5, v/v) had physicochemical characteristics closer to or within the normal range of the substrates. The presence of 12% compost and 10% biochar in the mixtures had no adverse effect on lettuce seed germination and cumulative seed emergence, which ranged from 90 to 99%. The seedling growth in those mixes was vigorous and higher than in other mixtures. Coir-based growing media with municipal solid waste compost and compost plus biochar can reduce the use of peat to a percentage of 5–10% v/v and the use of 17–22% v/v of locally produced renewable resources. In addition, mixtures affected the total phenol content in the lettuce leaves. Future research is needed to assess the behavior of seedlings after their transplantation. Full article

(This article belongs to the Special Issue Soilless Culture—An Intensive Production Method on Its Way to Sustainability)

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8 pages, 853 KiB

Open AccessEditor’s ChoiceArticle

Propagation Characteristics of the Rare Endemic Rhododenderon micranthum Turcz.

by Sang Im Oh, Eun Hye Park, Hong Min Koh, Min Gil, Mi Jeong Yoon, Jun Kyu Bae and Chung Ho Ko

Horticulturae 2023, 9(1), 101; https://doi.org/10.3390/horticulturae9010101 - 12 Jan 2023

Cited by 1 | Viewed by 1351

Abstract

This study was conducted to examine the effect of plant growth regulators on the rooting and growth of Rhododendron micranthum Turcz., a rare plant in South Korea. Indole-3-butyric acid (IBA) 150, 250, 350 mg·L⁻¹ and α-naphthaleneacetic acid (NAA) 50, 150, 250 mg·L [...] Read more.

This study was conducted to examine the effect of plant growth regulators on the rooting and growth of Rhododendron micranthum Turcz., a rare plant in South Korea. Indole-3-butyric acid (IBA) 150, 250, 350 mg·L⁻¹ and α-naphthaleneacetic acid (NAA) 50, 150, 250 mg·L⁻¹ treatment groups were established and cutting was performed in a commercial growth medium in March 2021 with 3 replications of 10 plants per group. After 70 days, the longest initial root growth was observed under the NAA 150 and 250 mg·L⁻¹ treatments. Moreover, the number of roots and percentage of rooting were slightly higher in NAA 150 and 250 mg·L⁻¹, indicating that these treatments were more effective in promoting plant growth. The above-ground part of plants treated with NAA 150 and 250 mg·L⁻¹ had a taller plant height, longer and wider leaves, and a greater number of leaves compared to other groups. Accordingly, the survival rate of plants treated with NAA 150 and 250 mg·L⁻¹ was higher than 80%, suggesting well-established roots and excellent above-ground growth. Therefore, treatment with growth regulator NAA at 150 and 250 mg·L⁻¹ is considered beneficial for the cutting of R. micranthum Turcz. Full article

(This article belongs to the Section Propagation and Seeds)

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10 pages, 8758 KiB

Open AccessEditor’s ChoiceArticle

Effects of Vernalization on Off–Season Flowering and Gene Expression in Sub-Tropical Strawberry cv. Pharachatan 80

by Thanyarat Thammasophon, Tonapha Pusadee, Weenun Bundithya and Daruni Naphrom

Horticulturae 2023, 9(1), 87; https://doi.org/10.3390/horticulturae9010087 - 10 Jan 2023

Cited by 2 | Viewed by 2445

Abstract

Off-season strawberry production may diversify the yield, thereby increasing costs, but the environmental conditions are a limiting factor. This experiment aimed to study the effects of vernalization on off-season flowering and gene expression in sub-tropical strawberry cv. Pharachatan 80. The factorial (2 × [...] Read more.

Off-season strawberry production may diversify the yield, thereby increasing costs, but the environmental conditions are a limiting factor. This experiment aimed to study the effects of vernalization on off-season flowering and gene expression in sub-tropical strawberry cv. Pharachatan 80. The factorial (2 × 2) + 1 in a completely randomized design was used in this study. Factor A was the vernalization temperatures: 2 °C and 4 °C. Factor B was the vernalization periods: 1 week and 2 weeks, compared with non-vernalization (control). The expression profile of genes was determined after vernalization treatments. The results revealed an interaction between the two factors on the number of days it took the plants to bloom, the percentage of flowering, the number of inflorescences, the number of flowers per inflorescence and the number of flowers per plant, whereas the number of first flower bloom days, inflorescence length and flower size were not affected by the interaction between the two factors. Strawberry plants vernalized for 1 and 2 weeks at 2 °C showed earlier flowering (21.4 and 23.1 days, respectively) than did those vernalized at 4 °C (24.9 and 25.7 days, respectively). On the other hand, non-vernalized strawberry plants took longer to bloom, at 62.2 days. Strawberry plants vernalized at 2 °C for 2 weeks had the highest percentage of flowering, number of inflorescences, number of flowers per inflorescence and number of flowers per plant. The analysis on gene expression showed that VRN5, SOC1 and FT genes were upregulated after vernalization at 2 °C for 2 weeks, whereas gene expression of the control treatment was not detected. This study demonstrates that vernalization treatment could induce off-season flowering in sub-tropical strawberry cv. Pharachatan 80 by activating flowering genes. Full article

(This article belongs to the Special Issue Physiology and Molecular Biology of Flowering, Fruit Setting, Fruit Quality)

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15 pages, 5771 KiB

Open AccessEditor’s ChoiceArticle

Transcriptome Analysis of Rhododendron liliiflorum H. Lév. Flower Colour Differences

by Hang Zhang, Meifeng Chen, Xinglin Wang, Jin Dai, Xu Zhang, Zhengdong Zhang, Ximin Zhang, Ming Tang, Jing Tang, Jiyi Gong, Lunxian Liu and Yin Yi

Horticulturae 2023, 9(1), 82; https://doi.org/10.3390/horticulturae9010082 - 9 Jan 2023

Cited by 3 | Viewed by 1729

Abstract

Rhododendron liliiflorum H. Lév., with white outer edges and yellow inner edges of petals, is an ornamental flower that originated in China. In this study, we analysed the white (W) and yellow (Y) parts of R. liliiflorum flowers by RNA sequencing. Then, unigene [...] Read more.

Rhododendron liliiflorum H. Lév., with white outer edges and yellow inner edges of petals, is an ornamental flower that originated in China. In this study, we analysed the white (W) and yellow (Y) parts of R. liliiflorum flowers by RNA sequencing. Then, unigene assembly, unigene annotation, and classification of Eukaryotic Orthologous Groups (KOGs) were performed. Gene ontology (GO) classification and pathway enrichment analysis for unigenes were also conducted. A total of 219,221 transcripts and 180,677 unigenes of R. liliiflorum were obtained from 48.52 Gb of clean reads. Differentially expressed gene (DEG) analysis indicated that 2310 unigenes were upregulated and 3062 were downregulated in W vs. Y. Thirty-six of these DEGs were involved in the flavonoid biosynthesis pathway. Pathway enrichment analysis showed that DEGs were significantly enriched in phenylpropanoid, flavonoid, and isoflavone biosynthesis. The expression of dihydroflavonol-4-reductase (DFR) and chalcone synthase (CHS) may affect differences in R. liliiflorum flower colour. The findings on flavonoid biosynthesis and other related genes in this study will provide guidance for exploring the mechanism of flower colour formation in Rhododendron. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology Research on Ornamental Flower)

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18 pages, 1879 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Supplemental Lighting Quality Influences Time to Flower and Finished Quality of Three Long-Day Specialty Cut Flowers

by Caleb E. Spall and Roberto G. Lopez

Horticulturae 2023, 9(1), 73; https://doi.org/10.3390/horticulturae9010073 - 6 Jan 2023

Cited by 2 | Viewed by 1592

Abstract

Year-round demand for locally sourced specialty cut flowers continues to increase. However, due to low radiation intensities and temperatures, growers in northern latitudes must utilize greenhouses, but limited production information detailing manipulation of the radiation environment exists. Therefore, our objective is to quantify [...] Read more.

Year-round demand for locally sourced specialty cut flowers continues to increase. However, due to low radiation intensities and temperatures, growers in northern latitudes must utilize greenhouses, but limited production information detailing manipulation of the radiation environment exists. Therefore, our objective is to quantify the influence of supplemental lighting (SL) quality on time to flower and harvest and stem quality of three long-day specialty cut flowers. Godetia ‘Grace Rose Pink’ (Clarkia amoena), snapdragon ‘Potomac Royal’ (Antirrhinum majus), and stock ‘Iron Rose’ (Matthiola incana) plugs are transplanted into bulb crates and placed in one of six greenhouse compartments with SL providing a total photon flux density of 120 µmol·m⁻²·s⁻¹ from 0700 to 1900 HR. After four weeks, SL is extended to provide a 16 h photoperiod to induce flowering. SL treatments are provided by either high-pressure sodium (HPS) fixtures or various light-emitting diode (LED) fixtures. Treatments are defined by their 100 nm wavebands of blue (B; 400–500 nm), green (G; 500–600 nm), red (R; 600–700 nm), and far-red (FR; 700–800 nm) radiation (photon flux density in μmol·m⁻²·s⁻¹) as B₇G₆₀R₄₄FR₉ (HPS₁₂₀), B₂₀G₅₀R₄₅FR₅, B₂₀R₈₅FR₁₅, B₃₀G₂₅R₆₅, B₁₂₀, or R₁₂₀. Time to harvest (TTH) is up to 14, 15, and 10 d slower under R₁₂₀ SL for godetia, snapdragon, and stock, respectively, compared to the quickest treatments (HPS₁₂₀, B₁₂₀, and B₂₀R₈₅FR₁₅ SL). However, R₁₂₀ SL produces cut flowers up to 18% longer than those grown under the quickest treatments. Both broad-spectrum LED fixtures slightly delay TTH compared to the quickest treatments. Stem caliper is not commercially different between treatments for godetia or snapdragon, although stems are up to 14% thinner for stock grown under B₁₂₀ SL compared to the other treatments. Flower petal color is not commercially different between SL treatments. We recommend utilizing a SL fixture providing a spectrum similar to B₂₀R₈₅FR₁₅ SL or B₂₀G₅₀R₄₅FR₅, as they elicit desirable crop responses with minimal developmental, quality, and visibility tradeoffs. While HPS lamps perform similarly to the recommended fixtures, we recommend utilizing LEDs for their higher photon efficacy and potential energy savings. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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12 pages, 2426 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Proton Nuclear Magnetic Resonance (¹H NMR) Metabolic Profiles Discriminate Two Monovarietal Extra Virgin Olive Oils, Cultivars Arbequina and Koroneiki, with Different Geographical Origin

by Federica Angilè, Laura Del Coco, Chiara Roberta Girelli, Francesca Calò, Lucia Mazzi, Francesco Paolo Fanizzi, Gaetano Alessandro Vivaldi and Salvatore Camposeo

Horticulturae 2023, 9(1), 66; https://doi.org/10.3390/horticulturae9010066 - 5 Jan 2023

Cited by 1 | Viewed by 1432

Abstract

This study aims to evaluate the Proton Nuclear Magnetic Resonance (¹H-NMR)-based metabolomic profiles of monovarietal olive oils obtained from Arbequina and Koroneiki, which are typically present in the Mediterranean basin and grown in Spain and Greece, respectively. Micro-milled oils were obtained [...] Read more.

This study aims to evaluate the Proton Nuclear Magnetic Resonance (¹H-NMR)-based metabolomic profiles of monovarietal olive oils obtained from Arbequina and Koroneiki, which are typically present in the Mediterranean basin and grown in Spain and Greece, respectively. Micro-milled oils were obtained from olives harvested both in their cultivar home countries (Spain and Greece) and in Italy. Investigations by ¹H NMR metabolic profiling were carried out to develop a strategy for the correct interpretation of differences based on geographical origins. The NMR Spectroscopy and multivariate statistical analysis (MVA) revealed significant differences in fatty acids profile as well as the unsaponifiable fraction, not only according to the cultivars but also to the specific geographical origin of the olives used. In particular, the oils from Spain were higher in polyunsaturated fatty acids (PUFAs) content than those from Italy. Conversely, the Italian oils of Koroneiki showed higher content of monounsaturated fatty acids (MUFAs) than Greek oils. Regarding the Extra Virgin Olive Oils (EVOOs) minor fraction, for both cultivars, the olive oils obtained using olives harvested in Italy were characterized by higher relative content of phenolic compounds. It was found that each of the investigated cultivars (Arbequina and Koroneiki), very popular in super high density (SHD) planting systems, assumed a specific well-characterized metabolic EVOO profile when the olives are harvested in Italy. These results may contribute to extending and enforcing available literature data on ¹H NMR-based chemometric models as powerful tools for EVOOs geographical origin discrimination. Full article

(This article belongs to the Section Fruit Production Systems)

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27 pages, 855 KiB

Open AccessEditor’s ChoiceReview

Biotechnologies and Strategies for Grapevine Improvement

by Anca Butiuc-Keul and Ana Coste

Horticulturae 2023, 9(1), 62; https://doi.org/10.3390/horticulturae9010062 - 4 Jan 2023

Cited by 6 | Viewed by 3512

Abstract

Grapevine (Vitis vinifera subsp. vinifera) is one of the most widespread and economically important perennial fruit crops in the world. Viticulture has changed over the years in response to changing environmental conditions and market demands, triggering the development of new and [...] Read more.

Grapevine (Vitis vinifera subsp. vinifera) is one of the most widespread and economically important perennial fruit crops in the world. Viticulture has changed over the years in response to changing environmental conditions and market demands, triggering the development of new and improved varieties to ensure the crop’s sustainability. The aim of this review is to provide a perspective on the recent developments in biotechnology and molecular biology and to establish the potential of these technologies for the genetic improvement of grapevine. The following aspects are discussed: (i) the importance of molecular marker-based methods for proper cultivar identification and how NGS-based high-throughput technologies have greatly benefited the development of genotyping techniques, trait mapping, and genomic selection; (ii) the recent advances in grapevine regeneration, genetic transformation, and genome editing, such as new breeding technology approaches for enhanced grapevine yield, quality improvement, and the selection of valuable varieties and cultivars. The specific problems and challenges linked to grapevine biotechnology, along with the importance of integrating classical and new technologies, are highlighted. Full article

(This article belongs to the Special Issue Plant Tissue and Organ Cultures for Crop Improvement in Omics Era)

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21 pages, 1692 KiB

Open AccessEditor’s ChoiceReview

Hydroponic Agriculture and Microbial Safety of Vegetables: Promises, Challenges, and Solutions

by Shlomo Sela Saldinger, Victor Rodov, David Kenigsbuch and Asher Bar-Tal

Horticulturae 2023, 9(1), 51; https://doi.org/10.3390/horticulturae9010051 - 3 Jan 2023

Cited by 14 | Viewed by 12599

Abstract

Hydroponics is a farming technique for growing plants with mineral nutrients using a soil-free medium. The plant roots are submerged in soil-free media, such as vermiculite or perlite, or just in mineral nutrient solutions. This allows for high production yields throughout the year [...] Read more.

Hydroponics is a farming technique for growing plants with mineral nutrients using a soil-free medium. The plant roots are submerged in soil-free media, such as vermiculite or perlite, or just in mineral nutrient solutions. This allows for high production yields throughout the year with less water and agro-chemical inputs. Consequently, hydroponics is considered a sustainable agriculture technology. Hydroponically grown crops are usually protected from the diseases transmitted through soil or animals in open fields. Therefore, they require fewer chemicals for pest control and are safer than conventionally grown crops in terms of possible chemical contamination. Nevertheless, hydroponics guarantees neither plant health nor the microbial safety of fresh produce. In the case of microbial contamination by human pathogens, unlike soil-grown crops, the pathogens may rapidly spread through the circulating water and simultaneously infect all the plants in the facility. This review summarizes the up-to-date knowledge regarding the microbial safety of hydroponically grown crops and discusses the role of the hydroponic system in reducing the microbial hazards for leafy and fruity crops as well as the potential risks for contamination by human pathogens. Finally, it outlines the approaches and the available science-based practices to ensure produce safety. The contamination risk in hydroponic systems may be diminished by using novel planting materials and the appropriate decontamination treatment of a recirculating liquid substrate; by modulating the microbiota interactions; and by following strict phytosanitary measures and workers’ hygienic practices. There is a timely need to adopt measures, such as the Good Agricultural Practice (GAP) guidelines, to mitigate the risks and ensure safe hydroponically grown vegetables for consumers. Full article

(This article belongs to the Special Issue Food Quality and Safety of Fresh and Fresh-Cut Produce)

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20 pages, 2042 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Fruit Crop Improvement with Genome Editing, In Vitro and Transgenic Approaches

by Suprasanna Penna and Shri Mohan Jain

Horticulturae 2023, 9(1), 58; https://doi.org/10.3390/horticulturae9010058 - 3 Jan 2023

Cited by 3 | Viewed by 5722

Abstract

Fruit species contribute to nutritional and health security by providing micronutrients, antioxidants, and bioactive phytoconstituents, and hence fruit-based products are becoming functional foods presently and for the future. Although conventional breeding methods have yielded improved varieties having fruit quality, aroma, antioxidants, yield, and [...] Read more.

Fruit species contribute to nutritional and health security by providing micronutrients, antioxidants, and bioactive phytoconstituents, and hence fruit-based products are becoming functional foods presently and for the future. Although conventional breeding methods have yielded improved varieties having fruit quality, aroma, antioxidants, yield, and nutritional traits, the threat of climate change and need for improvement in several other traits such as biotic and abiotic stress tolerance and higher nutritional quality has demanded complementary novel strategies. Biotechnological research in fruit crops has offered immense scope for large-scale multiplication of elite clones, in vitro, mutagenesis, and genetic transformation. Advanced molecular methods, such as genome-wide association studies (GWAS), QTLomics, genomic selection for the development of novel germplasm having functional traits for agronomic and nutritional quality, and enrichment of bioactive constituents through metabolic pathway engineering and development of novel products, are now paving the way for trait-based improvement for developing genetically superior varieties in fruit plant species for enhanced nutritional quality and agronomic performance. In this article, we highlight the applications of in vitro and molecular breeding approaches for use in fruit breeding. Full article

(This article belongs to the Special Issue Towards Tissue Culture in Fruit Trees: Latest Advances and Prospects)

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17 pages, 55980 KiB

Open AccessEditor’s ChoiceArticle

Genome Size, Flowering, and Breeding Compatibility in Osmanthus Accessions

by Lisa Alexander

Horticulturae 2023, 9(1), 56; https://doi.org/10.3390/horticulturae9010056 - 3 Jan 2023

Cited by 1 | Viewed by 1322

Abstract

Extending the range of Osmanthus species into more cold-hardy climates would open new opportunities for adoption and use of these species by growers, landscapers, and the public. Breeding improvement is hindered by few available cultivars and a lack of female or perfect flowers. [...] Read more.

Extending the range of Osmanthus species into more cold-hardy climates would open new opportunities for adoption and use of these species by growers, landscapers, and the public. Breeding improvement is hindered by few available cultivars and a lack of female or perfect flowers. The objectives of this study were to evaluate floral morphology and pollination biology of Osmanthus species available in the U.S. market. Thirty-three genotypes representing four species were evaluated in McMinnville, TN, USA for genome size, floral morphology, pollen viability, and self- and cross-compatibility. All genotypes were diploid with 2C genome sizes ranging from 2.89 to 3.21 pg. Perfect flowers were observed in all O. armatus and 82% of O. heterophyllus genotypes. All observed O. fortunei and O. fragrans genotypes had male-only flowers. Pollen viability based on staining and in vitro germination ranged from 8% to 98% and 6% to 53%, respectively. Pollen germination was observed on stigmas of 94.2% of O. armatus and O. heterophyllus flowers collected 24 hours after cross- or self-pollination. There was a significant association between cross type and percentage of flowers with pollen tubes reaching the ovaries; after 72 h, pollen tubes had reached the ovaries of in 67% of intraspecific crosses, 78% of interspecific crosses, and 0% of self crosses (χ² = 26.5, p < 0.001). This study provides evidence of a self-incompatibility system in O. armatus and O. heterophyllus and provides insights into opportunities and challenges for Osmanthus hybrid breeding. Full article

(This article belongs to the Special Issue Genetic Improvement of Horticultural Plants with Special Emphasis on Ornamentals)

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14 pages, 3279 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

In-Orchard Sizing of Mango Fruit: 2. Forward Estimation of Size at Harvest

by Marcelo H. Amaral and Kerry B. Walsh

Horticulturae 2023, 9(1), 54; https://doi.org/10.3390/horticulturae9010054 - 3 Jan 2023

Cited by 9 | Viewed by 2024

Abstract

Forecast of tree fruit yield requires prediction of harvest time fruit size as well as fruit number. Mango (Mangifera indica L.) fruit mass can be estimated from correlation to measurements of fruit length (L), width (W) and thickness (T). On-tree measurements of [...] Read more.

Forecast of tree fruit yield requires prediction of harvest time fruit size as well as fruit number. Mango (Mangifera indica L.) fruit mass can be estimated from correlation to measurements of fruit length (L), width (W) and thickness (T). On-tree measurements of individually tagged fruit were undertaken using callipers at weekly intervals until the fruit were past commercial maturity, as judged using growing degree days (GDD), for mango cultivars ‘Honey Gold’, ‘Calypso’ and ‘Keitt’ at four locations in Australia and Brazil during the 2020/21 and 21/22 production seasons. Across all cultivars, the linear correlation of fruit mass to LWT was characterized by a R² of 0.99, RMSE of 29.9 g and slope of 0.5472 g/cm³, while the linear correlation of fruit mass to

L (\frac{(W + T)}{2}

)², mimicking what can be measured by machine vision of fruit on tree, was characterized by a R² of 0.97, RMSE of 25.0 g and slope of 0.5439 g/cm³. A procedure was established for the prediction of fruit size at harvest based on measurements made five and four or four and three weeks prior to harvest (approx. 514 and 422 GDD, before harvest, respectively). Linear regression models on weekly increase in fruit mass estimated from lineal measurements were characterized by an R² > 0.88 for all populations, with an average slope (rate of increase) of 19.6 ± 7.1 g/week, depending on cultivar, season and site. The mean absolute percentage error for predicted mass compared to harvested fruit weight for estimates based on measurements of the earlier and later intervals was 16.3 ± 1.3% and 4.5 ± 2.4%, respectively. Measurement at the later interval allowed better accuracy on prediction of fruit tray size distribution. A recommendation was made for forecast of fruit mass at harvest based on in-field measurements at approximately 400 to 450 GDD units before harvest GDD and one week later. Full article

(This article belongs to the Special Issue Plant-Based, Proximal and Remote Sensing in Orchards and Vineyards — State of the Art, Challenges, Data Fusion and Integration)

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14 pages, 1637 KiB

Open AccessEditor’s ChoiceArticle

Tolerance and Physiological Responses of Citrus Rootstock Cultivars to Boron Toxicity

by Wanyun Yang, Huidong Yang, Lili Ling, Changpin Chun and Liangzhi Peng

Horticulturae 2023, 9(1), 44; https://doi.org/10.3390/horticulturae9010044 - 2 Jan 2023

Cited by 1 | Viewed by 1745

Abstract

Boron (B) is an essential trace nutrient element for citrus, but excessive B levels are frequently encountered in citrus production, potentially resulting in citrus toxicity. To better understand the tolerance and physiological responses of citrus rootstocks to excess B levels, Trifoliate orange, Ziyangxiangcheng, [...] Read more.

Boron (B) is an essential trace nutrient element for citrus, but excessive B levels are frequently encountered in citrus production, potentially resulting in citrus toxicity. To better understand the tolerance and physiological responses of citrus rootstocks to excess B levels, Trifoliate orange, Ziyangxiangcheng, Carrizo citrange, and Red tangerine were treated with four B concentrations (0.05, 0.2, 0.8, and 3.2 mmol/L). High B concentrations resulted in leaf yellowing and shedding and eventual plant death. Chlorophyll content and photosynthetic capacity declined in response to high B concentrations, and relative leaf cell conductivity rose significantly. Trifoliate orange was the first to exhibit symptoms of B toxicity, with the highest levels of B-associated injury. As B concentrations rose, the height increment ratio declined, as did belowground and aboveground dry fresh weight. Soluble protein content initially rose and then fell, while proline content, SOD activity, and POD activity rose with B concentrations. B levels in these rootstocks also increased significantly, with the greatest increases in the leaves. Principal component analysis and subordinate function results revealed that the relative rank order for the B tolerance of citrus rootstocks was: Red tangerine > Carrizo citrange > Ziyangxiangcheng > Trifoliate orange. Full article

(This article belongs to the Special Issue Recent Trends in Citrus Cultivation and Physiology Research)

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16 pages, 3250 KiB

Open AccessEditor’s ChoiceArticle

BcAMT1;5 Mediates Nitrogen Uptake and Assimilation in Flowering Chinese Cabbage and Improves Plant Growth When Overexpressed in Arabidopsis

by Yunna Zhu, Lihua Zhong, Xinmin Huang, Wei Su, Houcheng Liu, Guangwen Sun, Shiwei Song and Riyuan Chen

Horticulturae 2023, 9(1), 43; https://doi.org/10.3390/horticulturae9010043 - 1 Jan 2023

Cited by 1 | Viewed by 1490

Abstract

Nitrogen (N) is a major limiting factor for plant growth and vegetable production. Understanding the regulatory mechanisms of N uptake, transport, and assimilation is key to improving N use efficiency in plants. Ammonium transporters (AMTs) play an important role in plant N metabolism. [...] Read more.

Nitrogen (N) is a major limiting factor for plant growth and vegetable production. Understanding the regulatory mechanisms of N uptake, transport, and assimilation is key to improving N use efficiency in plants. Ammonium transporters (AMTs) play an important role in plant N metabolism. In this study, we isolated an important AMT1 subfamily member (BcAMT1;5) with a highly conserved signatural AMT1 subfamily motif from flowering Chinese cabbage. Based on functional complementation in yeast mutant 31019b and overexpression of BcAMT1;5 in Arabidopsis, BcAMT1;5 is a functional AMT. Tissue expression analysis showed that BcAMT1;5 was mainly expressed in roots and showed multiple N regime transcript patterns to respond to varying nutritional conditions. This was up-regulated by N-deficiency and down-regulated by supplying NH₄⁺. The glucuronidase (GUS) activities of BcAMT1;5_pro::GUS showed a similar change in response to different N conditions. Overexpression of BcAMT1;5 accelerated the growth of transgenic seedlings, increased NH₄⁺ net influxes, and enhanced the content and accumulation of NH₄⁺ and NO₃⁻ at low N concentrations. Additionally, it increased the transcript levels of N assimilation-related genes in shoots. These results indicate that BcAMT1;5 may participate in N uptake and assimilation under various N conditions in flowering Chinese cabbage, but it was differed obviously from other AMT1s. Full article

(This article belongs to the Special Issue New Advance in Germplasm Resources, Biotechnology and Genetic Breeding of Vegetable Crops)

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17 pages, 1776 KiB

Open AccessFeature PaperEditor’s ChoiceReview

CRISPR-Cas Genome Editing for Horticultural Crops Improvement: Advantages and Prospects

by Elena B. Rukavtsova, Natalia S. Zakharchenko, Vadim G. Lebedev and Konstantin A. Shestibratov

Horticulturae 2023, 9(1), 38; https://doi.org/10.3390/horticulturae9010038 - 30 Dec 2022

Cited by 5 | Viewed by 4935

Abstract

Horticultural plants, in particular fruit trees, berry crops, and ornamentals, are valuable objects for studying their genetic and biochemical properties. Along with traditional methods of studying these plants, modern molecular genetic technologies are emerging, in particular genome editing using CRISPR/Cas9 nucleases. In this [...] Read more.

Horticultural plants, in particular fruit trees, berry crops, and ornamentals, are valuable objects for studying their genetic and biochemical properties. Along with traditional methods of studying these plants, modern molecular genetic technologies are emerging, in particular genome editing using CRISPR/Cas9 nucleases. In this review, we have analyzed modern advances in genome editing of horticultural plants. To date, it has become possible to improve many plant characteristics using this technology, e.g., making plants resistant to biotic and abiotic stress factors, changing the time of flowering and fruit ripening, changing the growth characteristics of plants, as well as the taste properties of their fruits. CRISPR/Cas9 genome editing has been successfully carried out for many horticultural plants. Dozens of genes from these plants have been modified by means of genome editing technology. We have considered the main ways of delivering genetic constructs to plants as well as limitations that complicate the editing of target genes. The article reviews the prospects of using genome editing to improve the valuable properties of plants important to humans. Full article

(This article belongs to the Special Issue Application of CRISPR Technology in Horticulture)

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21 pages, 1011 KiB

Open AccessEditor’s ChoiceReview

Biotechnological Interventions for Reducing the Juvenility in Perennials

by Pooja Manchanda, Maninder Kaur, Shweta Sharma and Gurupkar Singh Sidhu

Horticulturae 2023, 9(1), 33; https://doi.org/10.3390/horticulturae9010033 - 29 Dec 2022

Cited by 2 | Viewed by 2699

Abstract

During shoot apex development, the plants undergo a very complex transition phase of flowering for successful reproduction, seed/cone setting and fruit development. The conversion of vegetative shoot meristems to floral meristems depends upon numerous endogenous, exogenous factors and flowering genes for the development [...] Read more.

During shoot apex development, the plants undergo a very complex transition phase of flowering for successful reproduction, seed/cone setting and fruit development. The conversion of vegetative shoot meristems to floral meristems depends upon numerous endogenous, exogenous factors and flowering genes for the development of floral parts. The perennial crops suffer from the limitation of the innate ability to keep some meristems in the vegetative state for the polycarpic growth habit leading to the long juvenile phase. Conventional breeding approaches viz. selection of early flowering parental lines, flower thinning and grafting are time-consuming requiring more time for the release of a new cultivar which is undesirable for rapid crop improvement. The best way to accelerate the perennial plant breeding improvement programs and to reduce the long juvenile phase is the induction of early flowering through the utilization of biotechnological approaches. The ability to allow the transmission of an early flowering gene to the progeny in a Mendelian fashion is the major advantage of biotechnological interventions. The introgression of early flowering traits from non-commercial germplasm or sexually compatible species to perennial species through the biotechnological aspects will act as a boon for crop improvement in future studies. The present review gives an overview of various flowering genes in perennial crops accompanying the implementation of biotechnological approaches including overexpression studies, RNA interference, Virus-induced flowering and CRISPR-Cas approaches that will help in reducing the period for induction of flowering in perennial crops. Full article

(This article belongs to the Section Developmental Physiology, Biochemistry, and Molecular Biology)

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18 pages, 4050 KiB

Open AccessEditor’s ChoiceArticle

Generating Novel Tomato Germplasm Using the Ancestral Wild Relative of Solanum pimpinellifolium

by Wenzhen Li, Yuhang Li, Yingnuan Liang, Linlin Ni, Huofeng Huang, Yushuang Wei, Mingcui Wang, Lida Zhang and Lingxia Zhao

Horticulturae 2023, 9(1), 34; https://doi.org/10.3390/horticulturae9010034 - 29 Dec 2022

Cited by 1 | Viewed by 2270

Abstract

To create novel tomato (Solanum lycopersicum) germplasm, a wild tomato relative, S. pimpinellifolium (a red-fruited LA1585 accession), was used as the male parent to cross with the yellow-fruited tomato mutant, e9292 (S. lycopersicum). Forty-four morphological characteristics were examined in [...] Read more.

To create novel tomato (Solanum lycopersicum) germplasm, a wild tomato relative, S. pimpinellifolium (a red-fruited LA1585 accession), was used as the male parent to cross with the yellow-fruited tomato mutant, e9292 (S. lycopersicum). Forty-four morphological characteristics were examined in the present study; 22 S. pimpinellifolium (LA1585) traits and six S. lycopersicum (e9292) traits were dominant in the hybrids (first generation, F₁); 10 were intermediate types, and the remaining six resulted in a nonmorphological difference. Ten representative lines were chosen from 1338 line of the second generation of the hybrid (e9292 × LA1585). The ascorbic acid content was higher in three F₂ hybrids than in LA1585, which had higher parental levels, as well as the lycopene content in two of the hybrid lines. The fructose and glucose contents were higher in five F₂ hybrids compared to e9292, and the sugar/acid value was higher in three hybrid lines. The broad-sense heritability values ranged from 75.06% for total soluble solids to 99.92% for ascorbic acid, and the average value was 92.66% for 15 quality traits. When seedlings were exposed to NaCl and mannitol, the tolerance of high salt concentrations and drought was enhanced in two hybrid lines (F₂-266 and F₂-299) compared with else tomatoes (e9292, LA1585, F₁ hybrids, and F₂-332). We created novel tomato germplasm resources with horticulturally desirable quality traits and abiotic stress tolerance, thus offering a methodology for novel tomato germplasm creation and evaluation. Full article

(This article belongs to the Collection Genetic Engineering and Quality Improvement in Vegetable Crops)

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15 pages, 6097 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Mechanical Winter Pruning on Vine Performances and Management Costs in a Trebbiano Romagnolo Vineyard: A Five-Year Study

by Gianluca Allegro, Roberta Martelli, Gabriele Valentini, Chiara Pastore, Riccardo Mazzoleni, Fabio Pezzi and Ilaria Filippetti

Horticulturae 2023, 9(1), 21; https://doi.org/10.3390/horticulturae9010021 - 23 Dec 2022

Cited by 2 | Viewed by 2108

Abstract

Vineyard mechanical winter pruning has been spreading worldwide, and the physiological basis ascribable to it has been consolidated throughout the years. Despite labor savings and reduction of costs having been proven, the demonstration of its economic viability might be challenging. In this context, [...] Read more.

Vineyard mechanical winter pruning has been spreading worldwide, and the physiological basis ascribable to it has been consolidated throughout the years. Despite labor savings and reduction of costs having been proven, the demonstration of its economic viability might be challenging. In this context, this work aims to evaluate the vine performances and the costs of different degrees of the mechanization of winter pruning over a five-year trial (2011–2015). In a vineyard of cv. Trebbiano Romagnolo (Vitis vinifera L.) located in northern Italy, three pruning treatments were laid out as follows: (a) manual pruning (MAN); (b) mechanical pre-pruning and simultaneous manual follow-up (MP + F); (c) mechanical pruning without a manual follow-up (MP). The results showed a strong increase in the node number of MP. Nevertheless, the yield compensation factors (i.e., the shoot fruitfulness and cluster weight) limited the increase in productivity. Soluble solids did not differ between the pruning treatments, while titratable acidity resulted slightly higher only on the MP berries. The MP treatment was the most economically convenient, with a vineyard surface of 1.5 hectares, while mechanical pruning with manual finishing resulted more advantageous, compared to manual pruning when the vineyard surface was greater than 2.9 hectares. The agronomic and economic results obtained in this five-year trial suggest that mechanical pruning may be profitably applied also on grapevine varieties characterized by low basal bud fruitfulness, such as Trebbiano Romagnolo. Full article

(This article belongs to the Topic Innovation and Solution for Sustainable Agriculture)

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15 pages, 1913 KiB

Open AccessEditor’s ChoiceArticle

Anemone Cut Flower Timing, Yield, and Quality in a High-Elevation Field and High Tunnel

by Shannon Rauter, Melanie Stock, Brent Black, Dan Drost, Xin Dai and Ruby Ward

Horticulturae 2023, 9(1), 2; https://doi.org/10.3390/horticulturae9010002 - 20 Dec 2022

Cited by 2 | Viewed by 1746

Abstract

A narrow window of optimal spring temperatures limits anemone (Anemone coronaria L.) cut flower production in the US Intermountain West, where fall plantings risk winter injury and spring plantings are limited by summer dormancy. Regional management recommendations are needed to improve anemone harvest [...] Read more.

A narrow window of optimal spring temperatures limits anemone (Anemone coronaria L.) cut flower production in the US Intermountain West, where fall plantings risk winter injury and spring plantings are limited by summer dormancy. Regional management recommendations are needed to improve anemone harvest timing and yield for growers in USDA hardiness zones 6 and below (average annual minimum temperatures below −18 °C). The aim of this research was to optimize flower timing, yield, quality, and profitability in high tunnel and field production systems by evaluating planting dates, winter insulation, tuber preparation, and cultivar selection. High tunnel and field trials were conducted from fall 2020 to spring 2022 in North Logan, UT (41.767° N, −111.811° W, 1405 m elevation, USDA hardiness zone 5). Tubers were pre-sprouted or directly planted into a high tunnel (left bare or covered with low tunnels) or field (left bare or covered with mulch, a low tunnel, or mulch and a low tunnel) from November to April. Harvest began as early as 2 March in the high tunnel and 9 April in the field, with overall average marketable yields (stems per m² ± SE) of 142 ± 7 in the high tunnel and 85 ± 4 in the field. Planting pre-sprouted tubers under low tunnels in the high tunnel in November delivered the earliest harvest (2 March), greatest marketable yield (280 stems per m² ± 73 SE), and greatest net returns ($38 per m²). For November field plantings, insulation improved emergence by 75% and marketable yield by 77 stems per m² ± 15 SE. Combining high tunnel and field production with the season advancement techniques of fall planting dates, low-cost insulation, and pre-sprouting resulted in high total yields in the Intermountain West compared to traditional industry recommendations. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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13 pages, 998 KiB

Open AccessEditor’s ChoiceArticle

A Novel Model Fusion Approach for Greenhouse Crop Yield Prediction

by Liyun Gong, Miao Yu, Vassilis Cutsuridis, Stefanos Kollias and Simon Pearson

Horticulturae 2023, 9(1), 5; https://doi.org/10.3390/horticulturae9010005 - 20 Dec 2022

Cited by 4 | Viewed by 1874

Abstract

In this work, we have proposed a novel methodology for greenhouse tomato yield prediction, which is based on a hybrid of an explanatory biophysical model—the Tomgro model, and a machine learning model called CNN-RNN. The Tomgro and CNN-RNN models are calibrated/trained for predicting [...] Read more.

In this work, we have proposed a novel methodology for greenhouse tomato yield prediction, which is based on a hybrid of an explanatory biophysical model—the Tomgro model, and a machine learning model called CNN-RNN. The Tomgro and CNN-RNN models are calibrated/trained for predicting tomato yields while different fusion approaches (linear, Bayesian, neural network, random forest and gradient boosting) are exploited for fusing the prediction result of individual models for obtaining the final prediction results. The experimental results have shown that the model fusion approach achieves more accurate prediction results than the explanatory biophysical model or the machine learning model. Moreover, out of different model fusion approaches, the neural network one produced the most accurate tomato prediction results, with means and standard deviations of root mean square error (RMSE), r2-coefficient, Nash-Sutcliffe efficiency (NSE) and percent bias (PBIAS) being 17.69 ± 3.47 g/m

^{2}

, 0.9995 ± 0.0002, 0.9989 ± 0.0004 and 0.1791 ± 0.6837, respectively. Full article

(This article belongs to the Topic Applications of Big Data and Machine Learning in Smart Agriculture)

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17 pages, 4835 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

In-Orchard Sizing of Mango Fruit: 1. Comparison of Machine Vision Based Methods for On-The-Go Estimation

by Chiranjivi Neupane, Anand Koirala and Kerry B. Walsh

Horticulturae 2022, 8(12), 1223; https://doi.org/10.3390/horticulturae8121223 - 19 Dec 2022

Cited by 11 | Viewed by 2034

Abstract

Estimation of fruit size on-tree is useful for yield estimation, harvest timing and market planning. Automation of measurement of fruit size on-tree is possible using RGB-depth (RGB-D) cameras, if partly occluded fruit can be removed from consideration. An RGB-D Time of Flight camera [...] Read more.

Estimation of fruit size on-tree is useful for yield estimation, harvest timing and market planning. Automation of measurement of fruit size on-tree is possible using RGB-depth (RGB-D) cameras, if partly occluded fruit can be removed from consideration. An RGB-D Time of Flight camera was used in an imaging system that can be driven through an orchard. Three approaches were compared, being: (i) refined bounding box dimensions of a YOLO object detector; (ii) bounding box dimensions of an instance segmentation model (Mask R-CNN) applied to canopy images, and (iii) instance segmentation applied to extracted bounding boxes from a YOLO detection model. YOLO versions 3, 4 and 7 and their tiny variants were compared to an in-house variant, MangoYOLO, for this application, with YOLO v4-tiny adopted. Criteria developed to exclude occluded fruit by filtering based on depth, mask size, ellipse to mask area ratio and difference between refined bounding box height and ellipse major axis. The lowest root mean square error (RMSE) of 4.7 mm and 5.1 mm on the lineal length dimensions of a population (n = 104) of Honey Gold and Keitt varieties of mango fruit, respectively, and the lowest fruit exclusion rate was achieved using method (ii), while the RMSE on estimated fruit weight was 113 g on a population weight range between 180 and 1130 g. An example use is provided, with the method applied to video of an orchard row to produce a weight frequency distribution related to packing tray size. Full article

(This article belongs to the Special Issue Plant-Based, Proximal and Remote Sensing in Orchards and Vineyards — State of the Art, Challenges, Data Fusion and Integration)

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16 pages, 3593 KiB

Open AccessEditor’s ChoiceArticle

Correlations between the Phylogenetic Relationship of 14 Tulasnella Strains and Their Promotion Effect on Dendrobium crepidatum Protocorm

by Jiayi Zhao, Zhenjian Li, Siyu Wang, Fu Yang, Lubin Li and Lei Liu

Horticulturae 2022, 8(12), 1213; https://doi.org/10.3390/horticulturae8121213 - 17 Dec 2022

Cited by 2 | Viewed by 1634

Abstract

The compatibility of mycorrhizal fungi with the early growth stage of orchids is essential for their growth. In this study, the compatibility and promotion effects of 14 Tulasnella strains from different hosts were studied by co-culturing them with the protocorms of Dendrobium crepidatum [...] Read more.

The compatibility of mycorrhizal fungi with the early growth stage of orchids is essential for their growth. In this study, the compatibility and promotion effects of 14 Tulasnella strains from different hosts were studied by co-culturing them with the protocorms of Dendrobium crepidatum, which has high ornamental and economic value in China. The ITS–LSU–SSU–TEF combined sequence analysis divided the 14 strains into three clades belonging to Tulasnella calospora (clades A and B) and Tulasnella asymmetrica (clade C). All the strains were compatible with D. crepidatum protocorms within 90 d of the co-culture. Strain T12 in Clade A had a significantly higher (p < 0.05) effect on the biomass and morphology of D. crepidatum, and strain T13 in Clade C had a significantly lower (p < 0.05) effect than the other strains. Through morphological principal component analysis, we constructed a hierarchical cluster analysis tree, which was consistent with the phylogenetic tree of these 14 strains at the clade level. Orthogonal partial least squares-discriminant analysis showed that these strains have an important effect on the plant height, root number, and length of D. crepidatum. The findings of this study will contribute to the identification of Tulasnella strains, conservation of D. crepidatum resources, and commercial utilization of mycorrhizal technology. Full article

(This article belongs to the Special Issue Mycorrhizal Roles in Horticultural Plants)

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22 pages, 656 KiB

Open AccessEditor’s ChoiceReview

Preharvest Elicitors Spray Improves Antioxidant Activity, Alleviates Chilling Injury, and Maintains Quality in Harvested Fruit

by Di Gong, Yang Bi, Yongcai Li, Yi Wang, Dov Prusky and Noam Alkan

Horticulturae 2022, 8(12), 1208; https://doi.org/10.3390/horticulturae8121208 - 16 Dec 2022

Cited by 9 | Viewed by 2087

Abstract

Antioxidant activity is an important feature for evaluating fruit quality and tolerance to biotic or abiotic stresses. Moreover, antioxidant activity is involved in chilling injury (CI) response and postharvest quality in fruit. Chemical elicitors can induce systemic acquired resistance in fruit against pathogens, [...] Read more.

Antioxidant activity is an important feature for evaluating fruit quality and tolerance to biotic or abiotic stresses. Moreover, antioxidant activity is involved in chilling injury (CI) response and postharvest quality in fruit. Chemical elicitors can induce systemic acquired resistance in fruit against pathogens, which could partially replace synthetic fungicides. Recently, researchers have found that preharvest sprays with chemical elicitors can improve antioxidant activity, reduce CI, and maintain quality in harvested fruit. In this review, we summarize that preharvest elicitors spray improve antioxidant activity in harvested fruit by promoting antioxidant components biosynthesis as well as antioxidant ability in vitro. Moreover, preharvest elicitors spray alleviates CI in fruit by regulation of membrane lipid metabolism and reactive oxygen species metabolism. In addition, preharvest elicitors spray maintains fruit quality by modulation of respiration and ethylene release. Finally, this review points out the issues existing and proposes an outlook on preharvest elicitors spray to maintain postharvest fruit quality. Full article

(This article belongs to the Special Issue Preharvest and Postharvest Factors Improving Horticultural Crops Quality and Shelf-Life)

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15 pages, 3399 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Monitoring Stem Water Potential with an Embedded Microtensiometer to Inform Irrigation Scheduling in Fruit Crops

by Alan N. Lakso, Michael Santiago and Abraham D. Stroock

Horticulturae 2022, 8(12), 1207; https://doi.org/10.3390/horticulturae8121207 - 16 Dec 2022

Cited by 10 | Viewed by 2978

Abstract

The water status of fruit and nut crops is critical to the high productivity, quality and value of these crops. Water status is often estimated and managed with indirect measurements of soil moisture and models of evapotranspiration. However, cultivated trees and vines have [...] Read more.

The water status of fruit and nut crops is critical to the high productivity, quality and value of these crops. Water status is often estimated and managed with indirect measurements of soil moisture and models of evapotranspiration. However, cultivated trees and vines have characteristics and associated cultural practices that complicate such methods, particularly variable discontinuous canopies, and extensive but low-density, variable root systems with relatively high hydraulic resistance. Direct and continuous measurement of plant water status is desirable in these crops as the plant integrates its unique combination of weather, soil and cultural factors. To measure plant water potential with high temporal sampling rates, a stem-embedded microchip microtensiometer sensor has been developed and tested in several fruit crops for long-term continuous monitoring of stem water potential. Results on several fruit crops in orchards and vineyards have been good to excellent, with very good correlations to the pressure chamber standard method. The primary challenge has been establishing and maintaining the intimate contact with the xylem for long periods of time, with variable stem anatomies, stem growth and wound reactions. Sources of variability in the measurements and utilization of the continuous data stream, in relation to irrigation scheduling, are discussed. Direct continuous and long-term field measurements are possible and provide unique opportunities for both research and farming. Full article

(This article belongs to the Special Issue Plant-Based, Proximal and Remote Sensing in Orchards and Vineyards — State of the Art, Challenges, Data Fusion and Integration)

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15 pages, 1601 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Different Physical Methods and Preservatives for Control of Fusarium proliferatum Rot in Garlic

by Laura La Placa, Paola Giorni, Letizia Mondani, Naresh Magan and Paola Battilani

Horticulturae 2022, 8(12), 1203; https://doi.org/10.3390/horticulturae8121203 - 15 Dec 2022

Cited by 1 | Viewed by 1548

Abstract

Dry rot is an emerging issue for garlic production worldwide and Fusarium proliferatum is its major causal agent. Since the disease is seed-transmitted, sowing healthy cloves is crucial. In this study, some disinfection strategies were tested on garlic seeds, including steam, dry heat, [...] Read more.

Dry rot is an emerging issue for garlic production worldwide and Fusarium proliferatum is its major causal agent. Since the disease is seed-transmitted, sowing healthy cloves is crucial. In this study, some disinfection strategies were tested on garlic seeds, including steam, dry heat, chemical disinfectants and gaseous ozone (O₃). Steam reduced the Colony Forming Units·g⁻¹ (CFUs·g⁻¹) by up to 92% in garlic seeds, but, at the same time, it affected their germination (−36%). Similarly, hydrogen peroxide (H₂O₂) and peracetic acid (C₂H₄O₃) reduced the CFUs·g⁻¹ by up to 83%; however, these methods also severely impaired germination (−40%). Dry heat did not negatively impact germination, but fungal contamination was not significantly reduced. The most promising strategy was gaseous O₃ treatment; it decreased CFUs·g⁻¹ by up to 96%, without causing any reduction of germination. The treatments applied were partially effective because the fungus is predominantly located in the outer layer of the seed, although it is also found in the inner portions. Some of these treatments can contribute to garlic protection from seed-borne pathogens and possibly reduce the occurrence of garlic dry rot. Full article

(This article belongs to the Special Issue Horticultural Plants Pathology and Advances in Disease Management)

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9 pages, 596 KiB

Open AccessEditor’s ChoiceArticle

Quality and Yield of Bell Pepper Cultivated with Two and Three Stems in a Modern Agriculture System

by Jorge Flores-Velazquez, Cándido Mendoza-Perez, Juan Enrique Rubiños-Panta and Jesus del Rosario Ruelas-Islas

Horticulturae 2022, 8(12), 1187; https://doi.org/10.3390/horticulturae8121187 - 13 Dec 2022

Cited by 4 | Viewed by 3770

Abstract

Bell pepper is a very important crop for its value in domestic and foreign markets. Actually, growers have adopted different management practices. In that aspect, management with different numbers of stems can define the quality and quantity of the product, as well as [...] Read more.

Bell pepper is a very important crop for its value in domestic and foreign markets. Actually, growers have adopted different management practices. In that aspect, management with different numbers of stems can define the quality and quantity of the product, as well as any increase in yield. The objective of this work was to evaluate the physical and chemical characteristics of fruits in terms of the quality and postharvest of bell pepper, as well as the yield according to the number of stems grown in a hydroponic system under greenhouse conditions. The experiment consisted of four treatments: two stems (T1) and three stems (T2) on a ‘Cannon’ cultivar, as well as two stems (T3) and three stems (T4) on a ‘Bragi’ cultivar. Fruits were sampled to determine total soluble solids (TSS), titratable acidity (TA), pH, electrical conductivity (EC), maturity index (MI), vitamin C (VC), lycopene content, size, shape, color, firmness, and yield. High vitamin C concentration of 120 mg 100 g⁻¹ was found in both cultivars. Treatments from ‘Cannon’ had the higher TSS content, lycopene levels and firmness. Regarding the physical characteristics, T1 of ‘Cannon’ had better fruit size: 63% (large), 35% (medium) and 2% (small). The highest yield was obtained in T2 of ‘Bragi’ with 6.50 kg m⁻². It was observed that total number of fruits increased as the number of stems increased. However, the size of the fruits decreased. Full article

(This article belongs to the Special Issue Plant Factory and Modern Horticulture)

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14 pages, 3466 KiB

Open AccessEditor’s ChoiceArticle

Further Characterization of Host Preference of Acidovorax citrulli Based on Growth Competition between Group I and Group II Strains

by Yuwen Yang, Pei Qiao, Tielin Wang, Weiqin Ji, Nuoya Fei, Liqun Zhang, Wei Guan and Tingchang Zhao

Horticulturae 2022, 8(12), 1173; https://doi.org/10.3390/horticulturae8121173 - 9 Dec 2022

Cited by 4 | Viewed by 1525

Abstract

Acidovorax citrulli, the causal agent of bacterial fruit blotch, can be divided into two groups. Group I is mainly isolated from melon, and group II is mainly isolated from watermelon. In this study, group I and II strains were used to assess [...] Read more.

Acidovorax citrulli, the causal agent of bacterial fruit blotch, can be divided into two groups. Group I is mainly isolated from melon, and group II is mainly isolated from watermelon. In this study, group I and II strains were used to assess competition in vivo and in vitro by evaluating inhibition activity assays and by measuring population growth dynamics. Our results indicated that there is no mutual inhibition of growth between the two groups of strains in King’s B medium. The bacterial populations of A. citrulli strains were counted within 7 days after inoculation in melon and watermelon cotyledons and plotted against time to generate population growth curves. Area under the population growth curves was calculated. When the two groups of strains were inoculated separately into melon and watermelon cotyledons, the results of analysis of variance show that there was no significant difference. In this study, for the first time in an experimental setting, we inoculated two A. citrulli groups into melon and watermelon cotyledons at the same time and determined the population dynamics of each strain. The results showed that there was no significant difference between two group strains in melon cotyledons. However, in watermelon cotyledons, the area under population growth curves of group II strain were significantly higher than those of group I strain. Three-way analysis of variance results showed that there was interaction between host and grouping on the influence of strain population level (p < 0.0001). These data provide additional information on the host preference of different groups of A. citrulli. Full article

(This article belongs to the Special Issue Bacterial Diseases in Horticulture: Advances in the Study of Pathogens, Interaction with the Host, Diagnosis and Sustainable Control)

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