Horticulturae

13 pages, 230 KiB

Open AccessEditor’s ChoiceReview

Emerging Perspectives on Non-Chemical Weed Management Tactics in Container Ornamental Production in the United States

by Greeshmanth Alluri and Debalina Saha

Horticulturae 2024, 10(3), 281; https://doi.org/10.3390/horticulturae10030281 - 15 Mar 2024

Viewed by 2339

Weeds are undesirable plants that can interfere with human activities and can hamper crop production and practices. The competition among ornamentals and weeds for space, nutrition, light, and moisture within a restricted area, such as in container production, can be intense and destructive. [...] Read more.

Weeds are undesirable plants that can interfere with human activities and can hamper crop production and practices. The competition among ornamentals and weeds for space, nutrition, light, and moisture within a restricted area, such as in container production, can be intense and destructive. In response to increasing concerns regarding herbicide injuries and the effects of pesticide use on the environment, many growers are extremely interested in non-chemical pest-management approaches. There are various non-chemical strategies to control weeds in containers, which include scouting, sanitation practices, hand weeding, mulching, irrigation management, substrate stratification, mulch discs or geo discs, lid bags, and fertilizer placement. In a restricted growth environment, weeds have been shown to reduce crop growth significantly. Limited information is available on the effects of weed densities and container sizes on ornament–weed competition within containerized production and how the concepts of fertilizer placement can be used efficiently to control weeds in containers without using any herbicides on the ornamentals. There is an immediate need to evaluate the interference and competitive effects of pernicious weed species in container-grown ornamentals in the North Central United States and to develop effective non-chemical weed control strategies by altering fertilizer placement in container production. Full article

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

15 pages, 655 KiB

Open AccessEditor’s ChoiceReview

Postharvest Chemical Treatment of Physiologically Induced Stem End Blockage Improves Vase Life and Water Relation of Cut Flowers

by Ayesha Manzoor, Muhammad Ajmal Bashir, Muhammad Saqib Naveed, Muhammad Tanveer Akhtar and Shaista Saeed

Horticulturae 2024, 10(3), 271; https://doi.org/10.3390/horticulturae10030271 - 11 Mar 2024

Cited by 7 | Viewed by 3638

Abstract

Wound-induced xylem occlusion significantly affects the vase life of cut flowers, as oxidative stress and the polymerization of phenolic compounds lead to the deposition of phenolic compounds/secondary metabolites in the stem ends of cut flowers to heal open tissues of freshly cut stems [...] Read more.

Wound-induced xylem occlusion significantly affects the vase life of cut flowers, as oxidative stress and the polymerization of phenolic compounds lead to the deposition of phenolic compounds/secondary metabolites in the stem ends of cut flowers to heal open tissues of freshly cut stems and prevent microbial invasion. However, this deposition causes blockage of vessels, reduced water uptake, and shortened vase life. The physiological plugging of vessels is linked with various oxidative enzymes’ (PAL, PPOs, LACs, and COs) actions taken to increase the synthesis of different compounds, e.g., lignin, suberin, tyloses, gel, and latex, in wounded areas. The use of chemical preservatives/enzyme inhibitors is one of the safest and most efficient techniques employed to minimize vascular blockage and inhibit phenolic compounds deposition and exudation. This review mainly discusses the types of oxidative enzymes, their pathways and biochemistry along with production of secondary metabolites, their biosynthesis, and their modes of action involved in vascular blockage. It also summarizes the different types of preservatives used in postharvest treatments to improve relative water uptake, flower fresh weight, petal protein content, and hydraulic conductance and prolong the vase life of cut flowers during storage. It is hoped that this elaborate study will help researchers in designing new studies concerning occlusion caused by the accumulation of phenolic compounds in vessels. Full article

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

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15 pages, 2961 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Salinity and Drought on the Essential Oil Yield and Quality of Various Plant Species of the Lamiaceae Family (Mentha spicata L., Origanum dictamnus L., Origanum onites L.)

by Michalis K. Stefanakis, Anastasia E. Giannakoula, Georgia Ouzounidou, Charikleia Papaioannou, Vaia Lianopoulou and Eleni Philotheou-Panou

Horticulturae 2024, 10(3), 265; https://doi.org/10.3390/horticulturae10030265 - 10 Mar 2024

Cited by 5 | Viewed by 2533

Abstract

Mentha spicata L., Origanum dictamnus L., and Origanum onites L. are aromatic plants that produce very important essential oils. They are considered model plants with beneficial health properties due to their antioxidant content. Enhancing the yield while maintaining the quality of essential oil [...] Read more.

Mentha spicata L., Origanum dictamnus L., and Origanum onites L. are aromatic plants that produce very important essential oils. They are considered model plants with beneficial health properties due to their antioxidant content. Enhancing the yield while maintaining the quality of essential oil is of significant commercial importance. Salinization and drought cause various effects on the yield and quality of the bioactive constituents in essential oil. By assessing the response of these plants and their secondary metabolites accumulation to different salt stress and irrigation levels, this study aims to gain insights into how plants adapt to and cope with salinity and drought. A pot experiment was conducted in the spring of 2020 to assess the effect of salinity and drought stress on the growth and essential oils content of the three aromatic plant species mentioned above. The soil mixture used was perlite and peat in a ratio of 1:1:6, while four salinity treatments (25, 50, 100, and 150 mΜ NaCl) and two levels of irrigation were applied (100% and 50%). Salinity significantly affects total chlorophyll concentration especially in higher concentrations (100 and 150 mM) in M. spicata plants, especially under 50% soil water irrigation. Under the same conditions, M. spicata contained the higher proline concentration, which was significantly greater than that in O. dictamnus and O. onites. Similar variations of malondialdehyde and hydrogen hyperoxide were revealed among the three species, with significantly higher values in M. spicata when subjected to both excess salinity and drought conditions. The major compounds identified in M. spicata were carvone, in O. dictamnus carvacrol, and p-cymene and in O. onites carvacrol. It is important to highlight that O. onites had the highest concentration of essential oil, and that the concentration increased with the increase of NaCl. This suggests that the presence of NaCl in the soil may have a stimulating effect on the production of essential oil in O. onites. However, it is plausible that the stress caused by NaCl triggers a physiological response in O. onites, leading to increased production of essential oil. This could be a protective mechanism to enhance the plant’s resistance to the stressor. Overall, O. onites and O. dictamnus appeared to be more resistant to these stress conditions than M. spicata, since they maintained their growth and essential oil quality indicators at higher levels. These two species possess mechanisms that prevent or minimize lipid peroxidation, thus protecting their cell membranes and maintaining their ultrastructure integrity. Full article

(This article belongs to the Special Issue Horticulture Plants Stress Physiology)

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29 pages, 1589 KiB

Open AccessEditor’s ChoiceReview

Recent Advances in Molecular Genetics of Onion

by Suman Sharma, Anil Khar, Jiffinvir S. Khosa, Subhankar Mandal and Subas Malla

Horticulturae 2024, 10(3), 256; https://doi.org/10.3390/horticulturae10030256 - 7 Mar 2024

Cited by 8 | Viewed by 7956

Abstract

Onion is an important vegetable crop because it adds nutritional value and diversity to food preparation. Understanding recent advancements in onion molecular genetics is essential to improve production, quality, and disease resistance. Cutting-edge genomic technologies like genetic mapping and RNA sequencing reveal important [...] Read more.

Onion is an important vegetable crop because it adds nutritional value and diversity to food preparation. Understanding recent advancements in onion molecular genetics is essential to improve production, quality, and disease resistance. Cutting-edge genomic technologies like genetic mapping and RNA sequencing reveal important genes and pathways. The review examines the progress in utilizing various molecular markers to study genetic divergence. The exploration extends to understanding the genes and pathways responsible for bulb color and chemical composition and the genetic factors influencing bulbing, flowering, and vernalization. Additionally, the article explores quantitative trait loci associated with resistance to major damaging diseases and delves into the role of different loci in male sterility and hybrid development. The recent publication of the whole genome sequence of onions will lead to further identification of genes and understanding their roles and functions in metabolic pathways. Full article

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

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14 pages, 8671 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Identification of the PEBP Family Gene in Three Cymbidium Species and Its Expression Patterns Analysis in C. ensifolium

by Jinliao Chen, Fei Wang, Yangting Zhang, Ruiyue Zheng, Xiaopei Wu, Ye Ai, Sagheer Ahmad, Zhongjian Liu and Donghui Peng

Horticulturae 2024, 10(3), 252; https://doi.org/10.3390/horticulturae10030252 - 6 Mar 2024

Viewed by 1759

Abstract

The PEBP gene family is involved in many biological processes in plants, including plant growth and development, flowering regulation, light response, and abiotic stress response. But there is little information about the role of the PEBP gene family in Cymbidium species. In this [...] Read more.

The PEBP gene family is involved in many biological processes in plants, including plant growth and development, flowering regulation, light response, and abiotic stress response. But there is little information about the role of the PEBP gene family in Cymbidium species. In this study, we identified 11, 9, and 7 PEBP genes in C. ensifolium, C. sinense, and C. goeringii, respectively, and mapped them to the chromosomes. We also studied the physicochemical characteristics of the proteins encoded by these PEBPs and analyzed their intra-species collinearity, gene structure, conserved motifs, and cis-acting elements. Furthermore, a total of forty PEBP genes from C. sinense, C. ensifolium, C. goeringii, Phalaenopsis, and Arabidopsis were divided into three clades based on the phylogenetic tree. The expression patterns of 11 PEBP genes in different tissues and organs of C. ensifolium were analyzed based on transcriptome data, indicating that the CePEBPs might play an important role in the growth and development, especially in the flower bud organs (1–5 mm). CePEBP5 plays an indispensable role in both the vegetative and reproductive growth cycles of C. ensifolium. CePEBP1 is essential for root development, while CePEBP1, CePEBP3, CePEBP5, and CePEBP10 regulate the growth and development of different floral organ tissues at various stages. The findings of this study can do a great deal to understand the roles of the PEBP gene family in Cymbidium. Full article

(This article belongs to the Special Issue Advancement in Propagation, Breeding, Cultivation and Marketing of Ornamentals)

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12 pages, 4251 KiB

Open AccessEditor’s ChoiceArticle

Efficient and Direct Identification of Ditylenchus destructor and D. dipsaci in Soil and Plant Tissues Using a Species-Specific PCR Assay

by Xu Han, Qing Chang, Youxian Xu, Pengjun Wang, Huixia Li, Yunqing Li, Yanshan Li, Wenkun Huang, Lingan Kong, Shiming Liu, Deliang Peng and Huan Peng

Horticulturae 2024, 10(3), 250; https://doi.org/10.3390/horticulturae10030250 - 5 Mar 2024

Cited by 1 | Viewed by 2214

Abstract

Ditylenchus destructor and D. dipsaci are important nematodes that have a significant economic impact on agronomic and horticultural plants worldwide. Microscopic observation alone may not distinguish between D. destructor and D. dipsaci. Accurate and rapid identification of these two species is essential [...] Read more.

Ditylenchus destructor and D. dipsaci are important nematodes that have a significant economic impact on agronomic and horticultural plants worldwide. Microscopic observation alone may not distinguish between D. destructor and D. dipsaci. Accurate and rapid identification of these two species is essential for effective pest management. In the present study, a species-specific PCR assay was developed to detect and differentiate D. destructor and D. dipsaci based on the rDNA-ITS sequences. The primers developed in this study can specifically amplify fragments of DNA from D. destructor and D. dipsaci in the target population, without amplifying DNA from other non-target nematodes within the genus Ditylenchus. The sensitivity test revealed that this procedure has the ability to detect single second-stage juveniles (J2) of D. dipsaci at a dilution of 1/128 and D. destructor at a dilution of 1/64. Additionally, it can detect genomic DNA (gDNA) at concentrations of 10 pg/µL for D. dipsaci and 1 ng/µL for D. destructor. These results align with previously reported results obtained through RPA and LAMP methods. Furthermore, the primers developed in this study for D. destructor not only were able to amplify six different haplotypes of nematodes but also successfully detected it in infested plant roots and soil samples, thereby shortening the time and reducing the number of steps required for detection. Thus, this assay, which does not necessitate taxonomic or morphological expertise, significantly enhances the diagnosis of D. destructor and D. dipsaci in infested fields. This advancement aids in the early control of these nematodes. Full article

(This article belongs to the Special Issue Mitigating Soil-Borne Diseases in Horticultural Crops: Current Challenges and Management Strategies)

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17 pages, 2439 KiB

Open AccessEditor’s ChoiceArticle

Effects of Long-Term High Temperatures in the Root Zone on the Physiological Characteristics of Grapevine Leaves and Roots: Implications for Viticulture Practices

by Yifan Su, Xinfeng Li, Zhiyi Cao, Zhen Gao and Yuanpeng Du

Horticulturae 2024, 10(3), 245; https://doi.org/10.3390/horticulturae10030245 - 3 Mar 2024

Cited by 3 | Viewed by 1803

Abstract

Ridging cultivation and root restriction cultivation are beneficial due to their improvement of the soil permeability in the root zone of grapevine, and they are widely used in southern China, Japan, and other countries. However, with the intensification of global warming, when using [...] Read more.

Ridging cultivation and root restriction cultivation are beneficial due to their improvement of the soil permeability in the root zone of grapevine, and they are widely used in southern China, Japan, and other countries. However, with the intensification of global warming, when using ridging or root restriction cultivation, the soil temperature in the root zone can often reach 30 °C or even more than 35 °C during the summer, which is not conducive to the growth of grapevines. The aim of this study was to explore the effects of high root zone temperatures on the photosynthetic fluorescence characteristics of grapevine leaves, root respiration, and degree of lignification of roots and shoots, as well as to provide a theoretical foundation for the management of grapevine production and cultivation. One-year-old potted ‘Kyoho’ was used as the study material. Three root temperature treatments were implemented for 15 days (9:00–16:00): 25 °C (CK), 30 °C (T1), and 35 °C (T2). The results showed that the malondialdehyde and H₂O₂ levels in leaves increased, while the chlorophyll content decreased. The oxygen-evolving complex was inactivated, and PSII donor and acceptor sides were blocked, thus reducing the photosynthetic gas exchange capacity at high root zone temperatures. The grapevine root activity and root/shoot ratio decreased. Simultaneously, the lignin content in the roots and shoots increased. In addition, there was a significant increase in the expression of key genes (PAL, C4H, 4CL, F5H, COMT, CCR, and CAD) in the root lignin synthesis pathway. Heightened root zone temperatures increased cyanide-resistant respiration in roots and heat release in the PPP pathway to alleviate stress damage. Therefore, it is recommended to use grass, mulching, and other cultivation management methods to maintain root zone temperatures below 30 °C in order to ensure the normal growth of grapevines and promote a high and stable yield. Full article

(This article belongs to the Special Issue Advances in Gene Regulation and Genetic Improvement of Fruit Trees)

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26 pages, 5738 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Identification and Pathogenicity of Biscogniauxia and Sordaria Species Isolated from Olive Trees

by Elena Petrović, Sara Godena, Jasenka Ćosić and Karolina Vrandečić

Horticulturae 2024, 10(3), 243; https://doi.org/10.3390/horticulturae10030243 - 2 Mar 2024

Cited by 9 | Viewed by 3128

Abstract

A field investigation of olive trees in Istria, Croatia, revealed branch dieback and cracked bark. Samples of diseased branches were collected from eight different locations and analysed. Additionally, meteorological data from two locations were analysed to determine if there was a connection between [...] Read more.

A field investigation of olive trees in Istria, Croatia, revealed branch dieback and cracked bark. Samples of diseased branches were collected from eight different locations and analysed. Additionally, meteorological data from two locations were analysed to determine if there was a connection between climatic changes and the appearance of pathogens in the region. Pathogenicity tests were conducted on olive seedlings. This study provides a description of Biscogniauxia and Sordaria species’ morphology and elucidates their phylogeny based on the internal transcribed spacer (ITS), beta-tubulin (TUB2) and translation elongation factor 1-alpha (TEF1- α) regions. This research represents the first documented occurrence of Biscogniauxia mediterranea causing charcoal disease in olive trees in Croatia. Additionally, it is the first report of Biscogniauxia nummularia (Bull.) Kuntze and Sordaria fimicola causing diseases in olive trees anywhere in the world. Furthermore, this study marks one of the initial forays into molecular investigations of these species isolated from olive trees. Considering the potential threat posed by the inherent aggressiveness of Biscogniauxia species, further research is deemed necessary to curb the development of charcoal disease. Full article

(This article belongs to the Special Issue Sustainable Production of Fruit Trees and Disease Resistance)

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20 pages, 4038 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Spatial Variability of Grape Berry Maturation Program at the Molecular Level

by Ron Shmuleviz, Alessandra Amato, Pietro Previtali, Elizabeth Green, Luis Sanchez, Maria Mar Alsina, Nick Dokoozlian, Giovanni Battista Tornielli and Marianna Fasoli

Horticulturae 2024, 10(3), 238; https://doi.org/10.3390/horticulturae10030238 - 29 Feb 2024

Cited by 1 | Viewed by 2546

Abstract

The application of sensors in viticulture is a fast and efficient method to monitor grapevine vegetative, yield, and quality parameters and determine spatial intra-vineyard variability. Molecular analysis at the gene expression level can further contribute to the understanding of the observed variability by [...] Read more.

The application of sensors in viticulture is a fast and efficient method to monitor grapevine vegetative, yield, and quality parameters and determine spatial intra-vineyard variability. Molecular analysis at the gene expression level can further contribute to the understanding of the observed variability by elucidating how pathways contributing to different grape quality traits behave in zones diverging on any of these parameters. The intra-vineyard variability of a Cabernet Sauvignon vineyard was evaluated through a Normalized Difference Vegetation Index (NDVI) map calculated from a multispectral image and detailed ground-truthing (e.g., vegetative, yield, and berry ripening compositional parameters). The relationships between NDVI and ground measurements were explored by correlation analysis. Moreover, berries were investigated by microarray gene expression analysis performed at five time points from fruit set to full ripening. Comparison between the transcriptomes of samples taken from locations with the highest and lowest NDVI values identified 968 differentially expressed genes. Spatial variability maps of the expression level of key berry ripening genes showed consistent patterns aligned with the vineyard vigor map. These insights indicate that berries from different vigor zones present distinct molecular maturation programs and suggest that transcriptome analysis may be a valuable tool for the management of vineyard variability. Full article

(This article belongs to the Section Viticulture)

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19 pages, 4545 KiB

Open AccessEditor’s ChoiceArticle

Combining Recurrent Neural Network and Sigmoid Growth Models for Short-Term Temperature Forecasting and Tomato Growth Prediction in a Plastic Greenhouse

by Yi-Shan Lin, Shih-Lun Fang, Le Kang, Chu-Chung Chen, Min-Hwi Yao and Bo-Jein Kuo

Horticulturae 2024, 10(3), 230; https://doi.org/10.3390/horticulturae10030230 - 27 Feb 2024

Cited by 5 | Viewed by 2163

Abstract

Compared with open-field cultivation, greenhouses can provide favorable conditions for crops to grow through environmental control. The prediction of greenhouse microclimates is a way to reduce environmental monitoring costs. This study used several recurrent neural network models, including long short-term memory (LSTM), gated [...] Read more.

Compared with open-field cultivation, greenhouses can provide favorable conditions for crops to grow through environmental control. The prediction of greenhouse microclimates is a way to reduce environmental monitoring costs. This study used several recurrent neural network models, including long short-term memory (LSTM), gated recurrent unit, and bi-directional LSTM, with varying numbers of hidden layers and units, to establish a temperature forecasting model for a plastic greenhouse. To assess the generalizability of the proposed model, the most accurate forecasting model was used to predict the temperature in a greenhouse with different specifications. During a test period of four months, the best proposed model’s R², MAPE, and RMSE values were 0.962, 3.216%, and 1.196 °C, respectively. Subsequently, the outputs of the temperature forecasting model were used to calculate growing degree days (GDDs), and the predicted GDDs were used as an input variable for the sigmoid growth models to simulate the leaf area index, fresh fruit weight, and aboveground dry matter of tomatoes. The R² values of the growth model for the three growth traits were all higher than 0.80. Moreover, the fitted values and the parameter estimates of the growth models were similar, irrespective of whether the observed GDD (calculated using the actual observed data) or the predicted GDD (calculated using the temperature forecasting model output) was used. These results indicated that the proposed temperature forecasting model could accurately predict the temperature changes inside a greenhouse and could subsequently be used for the growth prediction of greenhouse tomatoes. Full article

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

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13 pages, 2481 KiB

Open AccessEditor’s ChoiceArticle

Effects of N, P, K Nutrition Levels on the Growth, Flowering Attributes and Functional Components in Chrysanthemum morifolium

by Kaifang Jiang, Shu Peng, Zimeng Yin, Xiaohui Li, Lei Xie, Meichen Shen, Dahui Li and Junshan Gao

Horticulturae 2024, 10(3), 226; https://doi.org/10.3390/horticulturae10030226 - 27 Feb 2024

Cited by 3 | Viewed by 3650

Abstract

Fertilizer application is a decisive measure for the productivity of medicinal chrysanthemum plants. Therefore, determining the optimal doses of nutrients required for the growth and yield is crucial. In this study, we set out to investigate the effect of various nutrients on the [...] Read more.

Fertilizer application is a decisive measure for the productivity of medicinal chrysanthemum plants. Therefore, determining the optimal doses of nutrients required for the growth and yield is crucial. In this study, we set out to investigate the effect of various nutrients on the growth, yield, and functional components of chrysanthemum under eight different fertilization levels at seedling, branching, and flowering growth periods. The results show that plant height, stem diameter, and leaf area under the balance fertilization treatment were the highest (82 cm, 0.78 cm, and 38.50 cm², respectively), while the flower size and yield under the high potassium treatment were significantly increased compared to using balance fertilization. Chlorophyll content was also highest under the high potassium treatment. Moreover, plant defensive antioxidant peroxidase (POD) was responsive to low nitrogen treatment and low phosphorus treatment, while high potassium treatment enhanced the phenylalanine aminolase (PAL) activity and increased the content of flavonoids and chlorogenic acid in Chrysanthemum morifolium. In addition, low phosphorus treatment promoted the accumulation of flavonoids and chlorogenic acid content. Convincingly, the results show that growth, flowering, and functional indicators of chrysanthemum may thrive best under high potassium and balanced fertilization dosages, which will contribute to the development of a new economical chrysanthemum fertilizer ratio. Full article

(This article belongs to the Section Plant Nutrition)

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11 pages, 1952 KiB

Open AccessEditor’s ChoiceArticle

Identification of an Entomopathogenic Fungus, Pseudozyma flocculosa (Traquair, Shaw & Jarvis), and Its Efficacy against Tetranychus urticae Koch

by Yan Zhang, Rui Dong, Shouyin Hu, Zhaojiang Guo and Shaoli Wang

Horticulturae 2024, 10(3), 221; https://doi.org/10.3390/horticulturae10030221 - 25 Feb 2024

Cited by 1 | Viewed by 1932

Abstract

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most important agricultural pests worldwide, with chemical application being the primary control method. However, frequent heavy use or misuse of insecticides has accelerated the development of varying degrees of resistance in T. [...] Read more.

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most important agricultural pests worldwide, with chemical application being the primary control method. However, frequent heavy use or misuse of insecticides has accelerated the development of varying degrees of resistance in T. urticae. This makes the chemical control of this mite more challenging. Biocontrol methods have attracted much attention due to their safety and environment-friendly impact. Based on previous observations that the population of T. urticae was infected by unknown pathogenic fungi, we isolated, identified, and evaluated the pathogenicity of the fungi from infected mites. Through available morphological and molecular identification, the fungus was identified as Pseudozyma flocculosa. The virulence activity of the strain was evaluated at different concentrations of spore suspension (10⁶–10⁹ conidia/mL) using a spraying method. The strain showed pathogenic activity against the T. urticae in adult females that varied with different concentrations and temperatures. Meanwhile, the P. flocculosa also had a significant toxic effect on the developmental stages of T. urticae. In the laboratory bioassay, the mortality rate of the tested mites reached 100% at 9 d after P. flocculosa treatment. Additionally, a wettable powder processed with P. flocculosa conidia was applied on the T. urticae in the greenhouse and the control efficacy reached up to 90% at 7 d after treatment. The results showed a high insecticidal activity of P. flocculosa against T. urticae, indicating that this fungus possesses great potential for use as a bio-insecticidal agent. Full article

(This article belongs to the Special Issue Advancement in Mechanism of Vegetable Pest Catastrophe and Green Prevention and Control)

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17 pages, 2928 KiB

Open AccessEditor’s ChoiceReview

Powdery Mildew of Bigleaf Hydrangea: Biology, Control, and Breeding Strategies for Resistance

by Christina Jennings, Fulya Baysal-Gurel and Lisa W. Alexander

Horticulturae 2024, 10(3), 216; https://doi.org/10.3390/horticulturae10030216 - 24 Feb 2024

Cited by 6 | Viewed by 3415

Abstract

Hydrangea macrophylla, commonly known as bigleaf, garden, French, or florist hydrangea, is the most economically important member of the Hydrangea genus, with a breeding history spanning hundreds of years. Bigleaf hydrangea breeding improvement has largely focused on aesthetic traits and there are [...] Read more.

Hydrangea macrophylla, commonly known as bigleaf, garden, French, or florist hydrangea, is the most economically important member of the Hydrangea genus, with a breeding history spanning hundreds of years. Bigleaf hydrangea breeding improvement has largely focused on aesthetic traits and there are few varieties tolerant or resistant to major diseases such as powdery mildew. Powdery mildew is an obligate biotrophic Ascomycete in the order Erysiphales represented by approximately 900 species worldwide. The disease-causing agent in hydrangeas is Golovinomyces orontii (formerly Erysiphe polygoni DC), which tarnishes the beauty, growth, and salability of bigleaf hydrangea plants, especially those packed closely in production environments. Chemical or biological control is commonly used in production. A recently published haplotype-resolved genome of bigleaf hydrangea enables targeted analyses and breeding techniques for powdery mildew resistance. Analyzing transcriptomes of tolerant and susceptible hydrangeas through RNA sequencing will lead to the identification of differentially expressed genes and/or pathways. Concurrent application of marker-assisted selection, genetic transformation, and gene editing will contribute to the development of powdery-mildew-resistant varieties of bigleaf hydrangea. The aim of this review is to give a general overview of powdery mildew, its impact on bigleaf hydrangea, current control methods, molecular mechanisms, and breeding prospects for powdery mildew resistance in bigleaf hydrangea. Full article

(This article belongs to the Special Issue Enhancing Disease Resistance and Crop Quality through Innovative Breeding Approaches)

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12 pages, 6401 KiB

Open AccessEditor’s ChoiceArticle

Bioactive Compounds in the Residue Obtained from Fruits of Some Cultivars of Lonicera caerulea

by Sina Cosmulescu, Loredana Vijan, Ivona Cristina Mazilu and Georgiana Badea

Horticulturae 2024, 10(3), 211; https://doi.org/10.3390/horticulturae10030211 - 23 Feb 2024

Cited by 4 | Viewed by 1713

Abstract

This paper aimed to investigate the bioactive compounds in the dry powder residue of honeysuckle cultivars after extracting the juice. Based on the analyses performed on the total content of phenolic compounds, flavonoids, anthocyanins, tannins, carotenoids and vitamin C, the results indicated that [...] Read more.

This paper aimed to investigate the bioactive compounds in the dry powder residue of honeysuckle cultivars after extracting the juice. Based on the analyses performed on the total content of phenolic compounds, flavonoids, anthocyanins, tannins, carotenoids and vitamin C, the results indicated that dried Lonicera caerulea residue represented a rich source of phenolic compounds (8041.36 mg GAE 100 g⁻¹), of which about 80% were tannins (6432.10 mg GAE 100 g⁻¹). The flavonoid content varied around 2436.95 mg CE 100 g⁻¹. Vitamin C (185 mg 100 g⁻¹), lycopene and β-carotene (over 2.5 and 2.8 mg 100 g⁻¹, respectively) were also quantified. Among the phenolic acids, chlorogenic acid predominated (316 mg 100 g⁻¹), followed by cryptochlorogenic acid (135 mg 100 g⁻¹) and neochlorogenic acid (32 mg 100 g⁻¹). Flavonoids were mainly represented by catechin (2594 mg 100 g⁻¹) and anthocyanins (1442 mg 100 g⁻¹). Similar amounts of epicatechin and rutin were measured (156 mg 100 g⁻¹ and 148 mg 100 g⁻¹), while the isoquercetin concentration was below 15 mg 100 g⁻¹. In conclusion, the high level of phytocompounds and the diverse composition of dry Lonicera caerulea residue support its high nutraceutical value and high health-promoting potential. Full article

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

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16 pages, 2397 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Genetic Diversity and Agronomic Traits of Germplasm Resources of Stropharia rugosoannulata

by Miao Gu, Qiang Chen, Yan Zhang, Yongchang Zhao, Li Wang, Xiangli Wu, Mengran Zhao and Wei Gao

Horticulturae 2024, 10(3), 213; https://doi.org/10.3390/horticulturae10030213 - 23 Feb 2024

Cited by 7 | Viewed by 2171

Abstract

China possesses abundant wild germplasm resources and a wide range of cultivated strains of Stropharia rugosoannulata. However, issues such as genetic diversity and unclear genetic relationships have had an impact on the classification and preservation of germplasm resources, the breeding of new [...] Read more.

China possesses abundant wild germplasm resources and a wide range of cultivated strains of Stropharia rugosoannulata. However, issues such as genetic diversity and unclear genetic relationships have had an impact on the classification and preservation of germplasm resources, the breeding of new varieties, and the promotion of superior strains. There is an urgent need for genetic diversity analysis and assessment of germplasm resources. In this study, we conducted whole-genome resequencing of 50 cultivated and wild strains collected from various regions across the country. After applying a series of filtering parameters, we obtained 888,536 high-quality Single Nucleotide Polymorphism (SNP) markers. Using these SNP markers, we performed principal component analysis, population structure analysis, and phylogenetic clusters analysis on the 50 strains. Most cultivated strains exhibited high genetic similarity, while significant genetic diversity was observed among wild strains. Based on factors such as marker distribution throughout the entire genome and marker quality, we selected 358 core SNP markers to construct SNP fingerprints. Two-dimensional barcodes were generated for each strain to enable specific identification. Additionally, the mycelial growth rate of strains was evaluated on Potato Dextrose Agar (PDA) and substrate culture media. We also assessed their lignin degradation capability using guaiacol agar plates assay. It was observed that the mycelial growth rate on PDA and substrate culture medium exhibited a significant correlation with the diameter of the mycelial colony on guaiacol agar medium. Additionally, the correlation between the mycelial growth rate on the substrate medium and that on the guaiacol agar plate was stronger than that on PDA medium. This study provided molecular-level identification and assessment of germplasm resources. It clarified the genetic relationships among strains and the characteristics of mycelium growth-related agronomic traits of each strain. This research contributed to the enrichment and development of utilizable germplasm resources and breeding materials for S. rugosoannulata, offering a scientific basis for further research. Full article

(This article belongs to the Special Issue The Edible Mushroom Industry: A Vital Component in Horticultural Production)

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12 pages, 2118 KiB

Open AccessEditor’s ChoiceArticle

Active Packaging Systems to Extend the Shelf Life of ‘Italia’ Table Grapes

by Maíra Tiaki Higuchi, Aline Cristina de Aguiar, Nathalia Rodrigues Leles, Luana Tainá Machado Ribeiro, Bruna Evelise Caetano Bosso, Fábio Yamashita, Khamis Youssef and Sergio Ruffo Roberto

Horticulturae 2024, 10(3), 214; https://doi.org/10.3390/horticulturae10030214 - 23 Feb 2024

Cited by 3 | Viewed by 2507

Abstract

Sulfur dioxide (SO₂)-generating pads associated with perforated plastic liners are often used to control gray mold in table grapes during cold storage; however, SO₂ may cause bleaching, shattered berries, and an unwanted taste. To overcome this difficulty, a field ultrafast [...] Read more.

Sulfur dioxide (SO₂)-generating pads associated with perforated plastic liners are often used to control gray mold in table grapes during cold storage; however, SO₂ may cause bleaching, shattered berries, and an unwanted taste. To overcome this difficulty, a field ultrafast SO₂-generating pad was designed to be used for a few hours before packaging grape bunches as an alternative for eradicating spores of fungi from berry skin. This study aimed to assess the postharvest conservation and shelf life of ‘Italia’ table grapes packaged in plastic clamshells and perforated plastic liners using the field ultra-fast SO₂-generating pads before packaging, associated with or without slow- or dual-phase SO₂-generating pads during cold storage. The packaged grapes were cold stored (1.0 ± 1.0 °C; 95% relative humidity), and after 45 d, grapes were placed at room temperature (22.0 ± 1.0 °C) without plastic liners and SO₂-generating pads for 3 d. Before and after the grapes had been subjected to the field ultra-fast SO₂-generating pads, the quantification of filamentous fungi on the surface of the berries was assessed. The use of field ultra-fast SO₂-generating pads before packaging, associated with slow- or dual-phase SO₂-generating pads during cold storage, resulted in a lower incidence of gray mold after 45 d of storage, with low weight loss and shattered berries, good preservation of stem freshness, and no impairment in the color and firmness of the berries. Additionally, a significant decrease in disease incidence was observed when using only the dual-phase SO₂-generating pads in cold storage, with good maintenance of bunch quality. Full article

(This article belongs to the Special Issue Advances in Postharvest Packaging and Preservation Techniques)

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14 pages, 776 KiB

Open AccessEditor’s ChoiceArticle

High Outcrossing Levels among Global Macadamia Cultivars: Implications for Nut Quality, Orchard Designs and Pollinator Management

by Stephen J. Trueman, Mark G. Penter, Kátia Sampaio Malagodi-Braga, Joel Nichols, Anushika L. De Silva, Adalgisa Thayne Munhoz Ramos, Leonardo Massaharu Moriya, Steven M. Ogbourne, David Hawkes, Trent Peters, Naga Kasinadhuni, Shahla Hosseini Bai, Helen M. Wallace and Wiebke Kämper

Horticulturae 2024, 10(3), 203; https://doi.org/10.3390/horticulturae10030203 - 22 Feb 2024

Cited by 11 | Viewed by 2506

Abstract

Global fruit and nut yields are affected by shortfalls in pollinator populations, and pollen limitation is most prevalent among tropical, bee-pollinated and self-incompatible plants. Macadamia is a subtropical, bee-pollinated crop in which some cultivars have been found to be highly outcrossing. We aimed [...] Read more.

Global fruit and nut yields are affected by shortfalls in pollinator populations, and pollen limitation is most prevalent among tropical, bee-pollinated and self-incompatible plants. Macadamia is a subtropical, bee-pollinated crop in which some cultivars have been found to be highly outcrossing. We aimed to determine the extent of outcrossing and its effects on nut quality across a wide range of international macadamia cultivars in three countries. We sampled fruit from 19 macadamia cultivars across 23 sites in Australia, Brazil and South Africa. We used genotype-by-sequencing and MassARRAY methods to assign paternity to individual fruit and we assessed pollen-parent effects on nut quality. Macadamia was highly outcrossing, producing 80–100% of fruit by cross-pollination, at 17 of the 23 sites. Mixed mating (41–72% outcrossing) was identified at five sites, and low outcrossing (10%) was identified in one cultivar at one site where it was isolated from other flowering macadamia trees. Outcrossed fruit often had significantly better quality than selfed fruit, with 1.61–3.39 g higher nut-in-shell mass, 0.53–1.55 g higher kernel mass, 3.3–6.4% higher kernel recovery, and 3.0–3.5% higher oil concentration. The differences in kernel recovery equated to differences in value of USD 433–841 per ton of nut-in-shell at prices of USD 3000 per ton. In summary, macadamia cultivars were mostly highly outcrossing, and outcrossed nuts often had higher quality than selfed nuts. Growers should consider interplanting different cultivars more closely and distributing bee hives more widely to maximise cross-pollination, produce high yields, and optimise nut quality. Full article

(This article belongs to the Special Issue Modern Systems of Fruit Growing and Their Application for the Improvement of Tropical Fruit Products)

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17 pages, 5391 KiB

Open AccessEditor’s ChoiceArticle

Exogenous Abscisic Acid Regulates Anthocyanin Biosynthesis and Gene Expression in Blueberry Leaves

by Bin Ma, Yan Song, Xinghua Feng, Qingxun Guo, Lianxia Zhou, Xinsheng Zhang and Chunyu Zhang

Horticulturae 2024, 10(2), 192; https://doi.org/10.3390/horticulturae10020192 - 19 Feb 2024

Cited by 3 | Viewed by 2610

Abstract

Blueberry (Vaccinium corymbosum) leaves have a positive influence on health because of their phenolic contents, including anthocyanins. Phytohormone abscisic acid (ABA) promotes anthocyanin accumulation, but the underlying mechanisms are unclear in blueberry leaves. In this study, we found that exogenous ABA [...] Read more.

Blueberry (Vaccinium corymbosum) leaves have a positive influence on health because of their phenolic contents, including anthocyanins. Phytohormone abscisic acid (ABA) promotes anthocyanin accumulation, but the underlying mechanisms are unclear in blueberry leaves. In this study, we found that exogenous ABA promotes anthocyanin accumulation in blueberry leaves and we explored the global molecular events involved in these physiological changes by treating in vitro-grown blueberry seedlings with ABA and performing transcriptome deep sequencing (RNA-seq). We identified 6390 differentially expressed genes (DEGs), with 2893 DEGs at 6 h and 4789 at 12 h of ABA treatment compared to the control. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to plant hormone signal transduction and phenylpropanoid and flavonoid biosynthesis were significantly enriched at both stages of the ABA treatment. Analysis of DEGs in plant hormone signal transduction pathways revealed that exogenous ABA affected the expression of genes from other plant hormone signaling pathways, especially brassinosteroid, auxin, and gibberellin signaling. To elucidate the mechanism driving anthocyanin biosynthesis in blueberry in response to ABA treatment, we screened anthocyanin biosynthesis structural genes (ASG) from the phenylpropanoid and flavonoid biosynthetic pathways, MYB transcription factor genes from R2R3-MYB subgroups 5, 6, and 7 and ABRE-binding factor (ABF) genes from the ABA signal transduction pathway. Pearson’s correlation coefficient (r) analysis indicated that the ABFs, MYBs, and structural genes form a network to regulate ABA-induced anthocyanin biosynthesis and MYBA1 is likely to play an important role in this regulatory network. These findings lay the foundation for improving anthocyanin biosynthesis in blueberry leaves. Full article

(This article belongs to the Special Issue Advances in Developmental Biology in Tree Fruit and Nut Crops)

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20 pages, 5222 KiB

Open AccessEditor’s ChoiceReview

Phyllanthus Lignans: A Review of Biological Activity and Elicitation

by Winda Nawfetrias, Lukita Devy, Rizkita Rachmi Esyanti and Ahmad Faizal

Horticulturae 2024, 10(2), 195; https://doi.org/10.3390/horticulturae10020195 - 19 Feb 2024

Cited by 6 | Viewed by 4893

Abstract

The Phyllanthus genus exhibits a broad distribution spanning across the majority of tropical and subtropical regions. Due to their ability to synthesize medicinal bioactive compounds such as lignans, they have been utilized historically in traditional medicine to treat a wide range of ailments. [...] Read more.

The Phyllanthus genus exhibits a broad distribution spanning across the majority of tropical and subtropical regions. Due to their ability to synthesize medicinal bioactive compounds such as lignans, they have been utilized historically in traditional medicine to treat a wide range of ailments. This review discusses the current knowledge on the potency of lignans for medicinal purposes, the benefit of lignans for plants, various lignans produced by Phyllanthus, and how lignan synthesis could be increased through biotic and abiotic elicitation. Finally, we present a set of connected hypotheses to explain how signaling crosstalk between endophytic microbes and drought stress responses regulates lignan production. Although the mechanisms of lignan synthesis in Phyllanthus are not fully explored, this review strongly supports the view that endophytic fungi and drought stress can increase lignan production in plants belonging to the genus Phyllanthus. The medicinal plant–endophyte–drought stress relationship helps to improve the lignan yield of Phyllanthus, which is crucial for human health and can be optimized under in vitro and in vivo conditions. Full article

(This article belongs to the Section Biotic and Abiotic Stress)

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13 pages, 938 KiB

Open AccessEditor’s ChoiceArticle

Growing Salicornia europaea L. with Saline Hydroponic or Aquaculture Wastewater

by Martina Puccinelli, Ilaria Marchioni, Luca Botrini, Giulia Carmassi, Alberto Pardossi and Laura Pistelli

Horticulturae 2024, 10(2), 196; https://doi.org/10.3390/horticulturae10020196 - 19 Feb 2024

Cited by 9 | Viewed by 3472

Abstract

Among halophyte plants, Salicornia species (also known as glasswort or sea asparagus) are increasingly grown in open fields and greenhouses for edible or non-edible purposes. Their salinity tolerance makes it possible to irrigate Salicornia plants with saline waters and even seawater, which cannot [...] Read more.

Among halophyte plants, Salicornia species (also known as glasswort or sea asparagus) are increasingly grown in open fields and greenhouses for edible or non-edible purposes. Their salinity tolerance makes it possible to irrigate Salicornia plants with saline waters and even seawater, which cannot be used by other crop species. In this work, S. europaea (L.) was cultivated in pots under the typical climatic conditions of the fall season in the Mediterranean region and irrigated with non-saline standard nutrient solution (SNS) or saline wastewater discharged from a greenhouse semi-closed hydroponic (substrate) culture of tomato or a saltwater recirculating aquaculture system (RAS) with Gilthead sea bream (Spaurus aurata L., which was used as such or after dilution (50:50) with SNS. Plant growth was not significantly affected by the composition of irrigation water, while higher antioxidant capacity (measured using the DPPH assay) and concentration of photosynthetic pigments, phenols, flavonoids, and ascorbic acid were found in the shoots of SNS plants than in those of plants irrigated with wastewater. The level of lipid peroxidation and H₂O₂ production significantly increased in the SNS plants, which also showed higher activity of superoxide dismutase and lower activity of catalase. These results suggest that S. europaea can be cultivated using wastewater with moderate to high salinity discharged from greenhouse hydroponic crops or RASs, and that salt is not strictly required for the growth of this species. Using non-saline nutrient solution can result in moderate oxidative stress that improves the shoot quality of S. europaea. Full article

(This article belongs to the Collection Biosaline Agriculture)

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32 pages, 19325 KiB

Open AccessEditor’s ChoiceArticle

Seedling Growth Stress Quantification Based on Environmental Factors Using Sensor Fusion and Image Processing

by Sumaiya Islam, Md Nasim Reza, Shahriar Ahmed, Samsuzzaman, Yeon Jin Cho, Dong Hee Noh and Sun-Ok Chung

Horticulturae 2024, 10(2), 186; https://doi.org/10.3390/horticulturae10020186 - 18 Feb 2024

Cited by 4 | Viewed by 3110

Abstract

Understanding the diverse environmental influences on seedling growth is critical for maximizing yields. The need for a more comprehensive understanding of how various environmental factors affect seedling growth is required. Integrating sensor data and image processing techniques offers a promising approach to accurately [...] Read more.

Understanding the diverse environmental influences on seedling growth is critical for maximizing yields. The need for a more comprehensive understanding of how various environmental factors affect seedling growth is required. Integrating sensor data and image processing techniques offers a promising approach to accurately detect stress symptoms and uncover hidden patterns, enhancing the comprehension of seedling responses to environmental factors. The objective of this study was to quantify environmental stress symptoms for six seedling varieties using image-extracted feature characteristics. Three sensors were used: an RGB camera for color, shape, and size information; a thermal camera for measuring canopy temperature; and a depth camera for providing seedling height from the image-extracted features. Six seedling varieties were grown under controlled conditions, with variations in temperature, light intensity, nutrients, and water supply, while daily automated imaging was conducted for two weeks. Key seedling features, including leaf area, leaf color, seedling height, and canopy temperature, were derived through image processing techniques. These features were then employed to quantify stress symptoms for each seedling type. The analysis of stress effects on the six seedling varieties revealed distinct responses to environmental stressors. Integration of color, size, and shape parameters established a visual hierarchy: pepper and pak choi seedlings showed a good response, cucumber seedlings showed a milder response, and lettuce and tomato seedlings displayed an intermediate response. Pepper and tomato seedlings exhibited a wide range of growth stress symptoms, at 13.00% to 83.33% and 2.96% to 70.01%, respectively, indicating considerable variability in their reactions to environmental stressors. The suggested classification approach provides valuable groundwork for advancing stress monitoring and enabling growers to optimize environmental conditions. Full article

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

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13 pages, 1193 KiB

Open AccessEditor’s ChoiceArticle

Monofilament Shading Nets Improved Water Use Efficiency on High-Temperature Days in Grapevines Subjected to Hyperarid Conditions

by Gastón Gutiérrez-Gamboa, Emilio Villalobos-Soublett, Marco Garrido-Salinas and Nicolás Verdugo-Vásquez

Horticulturae 2024, 10(2), 176; https://doi.org/10.3390/horticulturae10020176 - 16 Feb 2024

Cited by 5 | Viewed by 1704

Abstract

(1) Background: Table grapes are often subjected to thermal stress during the growing season, affecting their production. Shading nets utilization has been proposed as an alternative to face this problem, but there is little available information about their effectiveness in hyperarid conditions. INIA-G2 [...] Read more.

(1) Background: Table grapes are often subjected to thermal stress during the growing season, affecting their production. Shading nets utilization has been proposed as an alternative to face this problem, but there is little available information about their effectiveness in hyperarid conditions. INIA-G2 vines were covered with kristall-colored mesh of 8% shade, and their ecophysiological responses were compared to uncovered vines during the daily cycle of two days with contrasting thermic conditions. (2) Methods: Net assimilation rate (A_N), stomatal conductance (g_s), transpiration (E), instantaneous water use efficiency (WUE: A_N E⁻¹), stem water potential (Ψ_s), air temperature (Ta) and vapor-pressure deficit (DPV) were determined in daily cycles (from 06:00 to 20:00 hrs) on two thermally contrasting days (330 DOY at 29.4 °C and 345 DOY at 22.6 °C) on grapevines without water restriction. (3) Results: The Ψ_s was not affected by treatment and day of measurement; nevertheless, A_N and g_s were statistically lower during 330 than 345 DOY (31% and 44% decrease, respectively). The covered vines presented less restrictive climatic conditions in terms of DPV in both DOY, reaching higher WUE values at 10, 12 and 14 h, which was associated with a decrease in E. (4) Conclusions: These results suggest that the use of shading nets can be an interesting alternative to cope with high temperatures in viticulture, improving the water use efficiency of vines. These are the first published results about the viticultural performance of the INIA-G2 variety. Full article

(This article belongs to the Section Viticulture)

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15 pages, 6098 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparison of Citrus Leaf Water Content Estimations Based on the Continuous Wavelet Transform and Fractional Derivative Methods

by Shiqing Dou, Wenjie Zhang, Yuanxiang Deng, Chenhong Zhang, Zhengmin Mei, Jichi Yan and Minglan Li

Horticulturae 2024, 10(2), 177; https://doi.org/10.3390/horticulturae10020177 - 16 Feb 2024

Cited by 6 | Viewed by 1507

Abstract

Citrus tangerines are famous fruits worldwide, and monitoring the water content of citrus leaves is highly important for citrus production. However, there are still challenges in quantitatively estimating the water content of citrus leaves using hyperspectral technology, and the random noise generated during [...] Read more.

Citrus tangerines are famous fruits worldwide, and monitoring the water content of citrus leaves is highly important for citrus production. However, there are still challenges in quantitatively estimating the water content of citrus leaves using hyperspectral technology, and the random noise generated during spectral acquisition and the overlapping peaks in the sensitive band of the citrus leaf water content will affect estimation accuracy. To solve these problems and further explore the roles of the continuous wavelet transform (CWT) and fractional-order derivative (FOD) in the estimation of citrus leaf water content, this study intends to use of CWT and FOD to decompose the original spectrum, and then compare the correlation between the original spectrum and leaf water content to explore whether the decomposition treatment has improved the correlation between spectrum and leaf moisture content. Then, the successive projections algorithm (SPA) was used to select feature bands and combine spectral vegetation indices. Partial least squares regression (PLSR) was used to construct water-content inversion models for citrus leaves, and the inversion accuracies of two commonly used spectral preprocessing methods were compared. The results indicate that (1) the CWT can improve the sensitivity of the spectrum to the citrus leaf water content to a certain extent, and the inversion accuracy of the CWT is approximately 5% greater than that of the FOD. (2) On the basis of the CWT and FOD methods, the inversion accuracy of the citrus leaf water content based on SPA screening increased by 9.61% and 9.29%, respectively, compared with the original spectrum. (3) Under CWT decomposition, Scale4 of the Gaus1 wavelet was screened by the SPA, and the inversion model of citrus leaf water content was constructed by combining the spectral vegetation index NDVI with the best results. The R-squared (

R^{2}

) and root mean square error (RMSE) values were 0.7491 and 0.0284, respectively, which were both 0.0138 greater than those of the best inversion model for the FOD

R^{2}

. In conclusion, the CWT-SPA combined with the spectral vegetation index can improve the sensitivity of the spectrum to the citrus leaf water content, eliminate a large amount of redundant data, and enhance the prediction ability and stability of the citrus leaf water content. Full article

(This article belongs to the Special Issue An Update of the Crop Management Practices Enhancing Yield and Quality in Citrus)

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17 pages, 1808 KiB

Open AccessEditor’s ChoiceArticle

Egyptian Citrus Essential Oils Recovered from Lemon, Orange, and Mandarin Peels: Phytochemical and Biological Value

by Faten Mohamed Ibrahim, Reda Sayed Mohammed, Eman Abdelsalam, Wedian El-Sayed Ashour, Daniela Magalhães, Manuela Pintado and El Sayed El Habbasha

Horticulturae 2024, 10(2), 180; https://doi.org/10.3390/horticulturae10020180 - 16 Feb 2024

Cited by 12 | Viewed by 3752

Abstract

Citrus peels are an important by-product of citrus processing industries, but a large part is considered waste. There has been increased attention in the last five years on these industrial by-products, especially those containing residual essential oils (EOs). Lemon, orange, and mandarin peels [...] Read more.

Citrus peels are an important by-product of citrus processing industries, but a large part is considered waste. There has been increased attention in the last five years on these industrial by-products, especially those containing residual essential oils (EOs). Lemon, orange, and mandarin peels from Egypt were subjected to hydro-distillation to obtain EOs, which were analyzed via mass spectrometry (GC/MS) and by building Global Natural Products Social Molecular Networking (GNPS-MN) for the purpose of visually exploring the volatile components of citrus species. The constructed MN revealed that D-Limonene, α-pinene, and β-pinene are the dominant volatile constituents in the three Egyptian citrus species. The EOs from three citrus peels exhibited promising activities as antioxidants using two tested methods: 1,1-diphenyl-2-picryl-hydrazil (DPPH) and nitric oxide (NO) compared with vitamin C. Lemon EO proved excellent antimicrobial activity against Gram-positive and negative bacteria. Additionally, the three citrus EOs showed good activities against the yeast Candida albicans. Regarding the anti-inflammatory assay, the three citrus EOs showed promising activities as COX-1 and COX-2 inhibitors. This study concludes that EOs extracted from citrus peel waste can be valorized as an innovative strategy for food preservation or may be incorporated in cosmetics and pharmaceutical formulations in alignment with circular economy principles. Full article

(This article belongs to the Special Issue Medicinal and Aromatic Plants: Isolation, Characterization and Biological Activities)

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15 pages, 1687 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Enhancing the Yield of Mature Olive Trees via Comparative Fertilization Strategies, including a Foliar Application with Fulvic and Humic Acids, in Non-Irrigated Orchards with Calcareous and Non-Calcareous Soils

by Stavros Sotiropoulos, Christos Chatzissavvidis, Ioannis E. Papadakis, Victor Kavvadias, Christos Paschalidis, Chrysovalantou Antonopoulou and Sotirios Kiriakopoulos

Horticulturae 2024, 10(2), 167; https://doi.org/10.3390/horticulturae10020167 - 12 Feb 2024

Cited by 4 | Viewed by 3187

Abstract

This study investigated the impact of fertilization treatments on mature, forty-year-old, fully productive olive trees (Olea europaea L. cv. Koroneiki) in two non-irrigated orchards featuring contrasting soil types: non-calcareous–acidic and calcareous–alkaline. Over three years (2019–2021), seven distinct treatments were applied, involving inorganic [...] Read more.

This study investigated the impact of fertilization treatments on mature, forty-year-old, fully productive olive trees (Olea europaea L. cv. Koroneiki) in two non-irrigated orchards featuring contrasting soil types: non-calcareous–acidic and calcareous–alkaline. Over three years (2019–2021), seven distinct treatments were applied, involving inorganic soil fertilizers (traditional strategy) and foliar applications of a liquid organic product containing fulvic and humic acids. Fertilization significantly influenced physiological parameters, such as mineral nutrition, photosynthetic pigments of olive leaves, fruit yield, and oil production per tree, revealing noteworthy effects influenced by soil types and their interactions with treatments. Statistical analysis highlighted specific treatments, indicating that the foliar application of the organic product once a year in alkaline soil or biannually in acidic soil resulted in the highest observed fruit yield and oil production per tree. Indeed, contrary to the control–unfertilized trees, specific fertilization strategies resulted in an average increase of up to 47% and 73% in fruit yield per tree and up to 96% and 100% in oil production per tree in acidic and alkaline soil, respectively. Furthermore, consistently high yields were correlated with constant high values of the chlorophyll a/chlorophyll b ratio (2.3–3.3 in August for acidic soil) and leaf chlorophyll a concentration (55–66 mg/100 g f.w. in August for alkaline soil). This novel finding underscores the crucial role of these factors as prerequisites for achieving superior fruit production. Our results emphasize the potential of integrating foliar organic fertilization as a complementary strategy to traditional soil-based approaches. This is particularly relevant under non-irrigated/rainfed cultural conditions, emphasizing the significance of considering alternative fertilization practices for optimized olive orchard management. Full article

(This article belongs to the Section Fruit Production Systems)

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23 pages, 10059 KiB

Open AccessEditor’s ChoiceArticle

Biological Control and Cross Infections of the Neofusicoccum spp. Causing Mango Postharvest Rots in Spain

by Lucía Guirado-Manzano, Sandra Tienda, José Antonio Gutiérrez-Barranquero, Antonio de Vicente, Francisco M. Cazorla and Eva Arrebola

Horticulturae 2024, 10(2), 166; https://doi.org/10.3390/horticulturae10020166 - 11 Feb 2024

Cited by 1 | Viewed by 2411

Abstract

Mango is one of the main subtropical crops growing in southern Spain. Spanish mango fruit production can be efficiently transported to the rest of Europe, and these mangoes are very appreciated for their quality and flavour. However, postharvest rots have been detected in [...] Read more.

Mango is one of the main subtropical crops growing in southern Spain. Spanish mango fruit production can be efficiently transported to the rest of Europe, and these mangoes are very appreciated for their quality and flavour. However, postharvest rots have been detected in stored mango fruits, making their commercialization difficult. The causal agents associated with such rot symptoms have been isolated and identified. Because the mango crops used to share the same growing area with avocado crops, fungal presence on surrounding asymptomatic avocado fruits was also analysed to detect potential cross infections. Artificial inoculation with Neofusicoccum parvum and N. mediterraneum was able to reproduce rot symptoms in mango but was also able to induce rots in avocado fruits. To approach a biological control strategy against these rot-producing fungi, two very well-known antagonistic biocontrol bacteria, Pseudomonas chlororaphis PCL1606, and Bacillus velezensis UMAF6639, were tested. The obtained results revealed that both bacteria can control the fungal rots on stored mango and avocado fruits under controlled conditions. Additionally, the strain B. velezensis UMAF6639 showed the ability to persist on the fruit surface of adult commercial trees in experiments under open field conditions, helping to prevent the appearance of these postharvest diseases. Full article

(This article belongs to the Special Issue Fungal Diseases and Pathogens Affecting Horticultural Crops: New Challenges)

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12 pages, 2915 KiB

Open AccessEditor’s ChoiceArticle

Temporary Immersion System as an Innovative Approach for In Vitro Propagation of Sorbus domestica L.

by Valeria Gianguzzi and Francesco Sottile

Horticulturae 2024, 10(2), 164; https://doi.org/10.3390/horticulturae10020164 - 10 Feb 2024

Cited by 6 | Viewed by 2654

Abstract

The genus Sorbus has maintained an extremely relevant role over time from a landscape and environmental perspective in many countries in the Mediterranean and Central Europe. Based on the requirements coming from the environmental policies provided in the European strategy Next Generation EU, [...] Read more.

The genus Sorbus has maintained an extremely relevant role over time from a landscape and environmental perspective in many countries in the Mediterranean and Central Europe. Based on the requirements coming from the environmental policies provided in the European strategy Next Generation EU, Sorbus has been considered a valuable species to be introduced in urban and peri-urban areas. The purpose of this study was to propagate four Sorbus accessions selected in the Sicilian territory, Southern Italy, using the liquid substrate in temporary immersion bioreactors Plantform™. The results obtained showed that the presence of 1 mg L⁻¹ mT in the substrate in combination with IBA 0.05 mg L⁻¹ produced a significant number of shoots (4.7) and a greater length (2.2 cm). Among the accessions, there were statistically significant differences; the accession SN2 and SN1 produced more shoots (respectively, 4.0 and 3.6), and a greater length of the shoots was observed in the selections SN4 and SN3 (respectively, 2.4 cm and 2.3 cm). The relative growth rate (RGR) was significantly influenced by the presence of the culture substrate of the combination of cytokines and auxin; SN4 selection showed the best RGR results of 8.3 mg⁻¹ d⁻¹. The use of the bioreactor Plantform™ in Sorbus domestica L. has favored a better development of plants obtained in vitro, demonstrating that this system is a valid alternative for the micropropagation of Sorbus. Full article

(This article belongs to the Section Propagation and Seeds)

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18 pages, 11766 KiB

Open AccessEditor’s ChoiceArticle

Characterization of Changes in Active Ingredients and Mining of Key Metabolites in Bletilla striata under Shading and Drought Stresses

by Ruoyong Yin, Leiru Chen, Pengfei Deng, Xiaoqing Cao and Xiaoniu Xu

Horticulturae 2024, 10(2), 163; https://doi.org/10.3390/horticulturae10020163 - 10 Feb 2024

Cited by 6 | Viewed by 1817

Abstract

Shading and drought are considered crucial abiotic stress factors that limit the normal growth of plants. Under natural conditions, the quality of Bletilla striata pseudobulbs (BP), a Chinese traditional medicinal crop, is often affected by the dual stresses of shading and drought. However, [...] Read more.

Shading and drought are considered crucial abiotic stress factors that limit the normal growth of plants. Under natural conditions, the quality of Bletilla striata pseudobulbs (BP), a Chinese traditional medicinal crop, is often affected by the dual stresses of shading and drought. However, the relationship and mechanism of the interaction between the two stress factors in B. striata remain unclear. In this study, we examined the changes in photosynthetic properties and active ingredients of B. striata under shading (L), drought (W), and shading-drought dual stresses (LW). We aimed to explore the metabolite mechanism that led to these changes using GC-MS-based non-targeted metabolomics techniques. The results indicated a significant reduction in the polysaccharide content of BP under W and LW treatments compared to the control (CK). The total phenol content was significantly reduced under L treatment, while the total flavonoid content did not change significantly under the three stresses. The significant increase in militarine content under all three stresses implies that B. striata may modulate its biosynthesis in response to different environmental stresses. Transpiration rate and stomatal conductance were reduced, amino acid expression was up-regulated, and carbohydrate expression was down-regulated in B. striata under L treatment. The net photosynthesis rate, stomatal conductance, and transpiration rate exhibited significant reductions, and the tuber metabolic disorder marker Homocysteine increased and organic acid content as well under W treatment. The net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency of B. striata were further reduced under LW compared with single stress, which is in agreement with the “trade-off theory”. Pseudobulb metabolite changes, in combination with the results of the two single stresses, showed an up-regulation of amino acids and disaccharide compounds and a down-regulation of monosaccharide compounds. A support vector machine model (SVM) was used to screen 10 marker metabolites and accurately predict the changes in active ingredient content through an artificial neural network model (ANN). The results suggest that an appropriate stress environment can enhance the content of the target active ingredients based on cultivation goals. Full article

(This article belongs to the Special Issue Plants Response to Abiotic Stresses: Strategies for Adaptations and Survival)

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37 pages, 2022 KiB

Open AccessEditor’s ChoiceReview

Recent Advancements in Mitigating Abiotic Stresses in Crops

by Yusuf Opeyemi Oyebamiji, Basit Akolade Adigun, Noraziyah Abd Aziz Shamsudin, Asmuni Mohd Ikmal, Monsuru Adekunle Salisu, Fadila Ahmad Malike and Adebola Azeez Lateef

Horticulturae 2024, 10(2), 156; https://doi.org/10.3390/horticulturae10020156 - 7 Feb 2024

Cited by 29 | Viewed by 10795

Abstract

In recent years, the progressive escalation of climate change scenarios has emerged as a significant global concern. The threat to global food security posed by abiotic stresses such as drought, salinity, waterlogging, temperature stress (heat stress, freezing, and chilling), and high heavy metal [...] Read more.

In recent years, the progressive escalation of climate change scenarios has emerged as a significant global concern. The threat to global food security posed by abiotic stresses such as drought, salinity, waterlogging, temperature stress (heat stress, freezing, and chilling), and high heavy metal accumulation is substantial. The implementation of any of these stresses on agricultural land induces modifications in the morphological, biochemical, and physiological processes of plants, leading to diminished rates of germination, growth, photosynthesis, respiration, hormone and enzyme activity disruption, heightened oxidative stress, and ultimately, a reduction in crop productivity. It is anticipated that the frequency of these stresses will progressively escalate in the future as a result of a rise in climate change events. Therefore, it is crucial to develop productive strategies to mitigate the adverse effects of these challenges on the agriculture industry and improve crop resilience and yield. Diverse strategies have been implemented, including the development of cultivars that are resistant to climate change through the application of both conventional and modern breeding techniques. An additional application of the prospective and emerging technology of speed breeding is the acceleration of tolerance cultivar development. Additionally, plant growth regulators, osmoprotectants, nutrient and water management, planting time, seed priming, microbial seed treatment, and arbuscular mycorrhiza are regarded as effective methods for mitigating abiotic stresses. The application of biochar, kaolin, chitosan, superabsorbent, yeast extract, and seaweed extract are examples of promising and environmentally benign agronomic techniques that have been shown to mitigate the effects of abiotic stresses on crops; however, their exact mechanisms are still not yet fully understood. Hence, collaboration among researchers should be intensified to fully elucidate the mechanisms involved in the action of the emerging technologies. This review provides a comprehensive and current compilation of scientific information on emerging and current trends, along with innovative strategies to enhance agricultural productivity under abiotic stress conditions. Full article

(This article belongs to the Section Biotic and Abiotic Stress)

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21 pages, 7059 KiB

Open AccessEditor’s ChoiceArticle

Optimized Fertilizer–Water Management Improves Carrot Quality and Soil Nutrition and Reduces Greenhouse Gas Emissions on the North China Plain

by Wenhui Tang, Cuiyue Zhang, Peiqiang Zhang, Ying Zhao, Mengyao Guo, Yun Li, Ruiping Chi and Yanling Chen

Horticulturae 2024, 10(2), 151; https://doi.org/10.3390/horticulturae10020151 - 6 Feb 2024

Cited by 1 | Viewed by 2436

Abstract

In order to improve carrot quality and soil nutrition and reduce the environmental pollution caused by intensive carrot production, more comprehensive combined water–fertilizer management strategies are necessary. This study hypothesizes that optimal management of water and fertilizer can improve carrot yield and quality [...] Read more.

In order to improve carrot quality and soil nutrition and reduce the environmental pollution caused by intensive carrot production, more comprehensive combined water–fertilizer management strategies are necessary. This study hypothesizes that optimal management of water and fertilizer can improve carrot yield and quality and reduce greenhouse gas emissions and soil nutrient residues. Thus, coordinated water–fertilizer management strategies were tested for carrot production on the North China Plain over two consecutive growing seasons. Four treatments were tested: local standard fertilization and irrigation practices (FNP); optimized irrigation and chemical nitrogen, phosphorus, and potassium fertilizer (OPT); OPT treatment with partial replacement of chemical fertilizer with peanut shell (PS); and OPT treatment with partial replacement of chemical fertilizer with mushroom residue (M). Compared to the FNP treatment, there were statistically significant increases in soluble sugars (12–27%) and free amino acids (14–26%), and decreases in the nitrate content (7–17%) of fleshy root in the OPT, PS, and M treatments. In autumn carrots, the OPT and M treatments decreased yield, whereas PS increased yield; spring carrot yield was significantly decreased in the OPT, PS, and M groups compared to the FNP group. There were no significant effects of the treatment group on carrot growth rates, nutrient accumulation, or nutrient distribution. However, the OPT, PS, and M treatments were associated with significantly increased partial productivity of phosphate fertilizer (233–363%), reduced residual levels of nitrate and available phosphorus in the top 80 cm of soil, and decreased greenhouse gas emissions by 8–18% compared to the FNP treatment. These results highlight the effectiveness of partial organic fertilizer substitution and integrated water–fertilizer management to produce high-quality carrots with minimal environmental damage. Full article

(This article belongs to the Section Plant Nutrition)

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28 pages, 1619 KiB

Open AccessEditor’s ChoiceReview

Advances in Orchid Biology: Biotechnological Achievements, Translational Success, and Commercial Outcomes

by Pragya Tiwari, Abhishek Sharma, Subir Kumar Bose and Kyeung-Il Park

Horticulturae 2024, 10(2), 152; https://doi.org/10.3390/horticulturae10020152 - 6 Feb 2024

Cited by 16 | Viewed by 7448

Abstract

Orchids constitute the largest and most diverse group of flowering plants and are classified in the family Orchidaceae. Exhibiting significance as the most exotic and ubiquitous flowering plant, the cultivation of orchids on a commercial level is gaining momentum worldwide. In addition to [...] Read more.

Orchids constitute the largest and most diverse group of flowering plants and are classified in the family Orchidaceae. Exhibiting significance as the most exotic and ubiquitous flowering plant, the cultivation of orchids on a commercial level is gaining momentum worldwide. In addition to its ornamental and aesthetic value, the orchid industry has successfully generated employment for people in developing countries. Recent advances in biotechnological interventions in orchids have substantially contributed to the development of exotic varieties with novel traits, not to forget the inputs of traditional plant breeding methods and tissue culture approaches. In addition, the scientific developments in orchid biology have remarkably bridged the knowledge gaps in areas of orchid classification, phytochemistry, and cultivation strategies. This has facilitated the commercialization of novel varieties, opening new avenues in the orchid industry, and their global marketing as cut flowers and artificially propagated plants. Orchids constitute the first floriculture crops that revolutionized the orchid industry; however, they also hold several challenges in the natural propagation and conservation of several species that are on the verge of extinction. International organizations like CITES have come forward to address challenges associated with illegal global trade and indiscriminate use of orchid varieties, aiming for conservation and legal commercial goals. This thematic review is one-of-a-kind in providing comprehensive insights into the emerging momentum of orchid biology and how its globalization projects to considerably impact the orchid industry in the coming times. However, it is imperative to understand the challenges in the cultivation and conservation of orchid varieties and ensure legislative guidelines both on domestic and global levels to ensure a multipronged approach to the conservation and commercialization of orchids. Full article

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

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47 pages, 1118 KiB

Open AccessFeature PaperEditor’s ChoiceReview

The Health of Vineyard Soils: Towards a Sustainable Viticulture

by Fernando Visconti, Roberto López and Miguel Ángel Olego

Horticulturae 2024, 10(2), 154; https://doi.org/10.3390/horticulturae10020154 - 6 Feb 2024

Cited by 27 | Viewed by 10011

Abstract

Soil health encompasses the effects the uppermost part of the land have on human wellbeing in a broad sense, because soil is where most food ultimately comes from, and because it more inconspicuously fulfils other ecological functions, as important as feeding, for our [...] Read more.

Soil health encompasses the effects the uppermost part of the land have on human wellbeing in a broad sense, because soil is where most food ultimately comes from, and because it more inconspicuously fulfils other ecological functions, as important as feeding, for our planet’s welfare, which is ours. Viticulture exploits the soil’s resources from which wine, its most valuable produce, boasts to obtain some of its unique quality traits, which are wrapped within the terroir concept. However, using conventional methods, viticulture also has harsh impacts on the soil, thus jeopardizing its sustainability. How long will the terroir expression remain unchanged as vineyard soil degradation goes on? While this question is difficult to answer because of the complex nature of terroirs, it is undeniable that conventional soil management practices in viticulture leave, in general, ample room for improvement, in their impact on vineyards as much as on the environment. In response, viticulture must adopt practices that enable the long-lasting preservation of its grounds for both on-farm and off-farm benefits. In this regard, the increase in the soil’s organic matter alongside the enhancement of the soil’s biological community are key because they benefit many other soil properties of a physical, chemical, and biological nature, thus determining the soil’s healthy functioning, where the vines may thrive for a long time, whereas its surroundings remain minimally disturbed. In the present review, the importance of soil health as it relates to vineyards is discussed, the soil degradation factors and processes that threaten winegrowing areas are presented, successful soil-health enhancement practices are shown, and future research trends are identified for the benefit of researchers and stakeholders in this special agricultural industry. Full article

(This article belongs to the Special Issue Sustainable Viticulture: Soil Fertility, Plant Nutrition and Grape Quality)

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12 pages, 507 KiB

Open AccessEditor’s ChoiceArticle

The Use of Cubic Smoothing Spline Models for Predicting Early Fruit Size in ‘Keenan’ Valencia (Citrus sinensis L. Osbeck) Oranges

by Tahir Khurshid, Ben Braysher and Jane Elizabeth Khurshid

Horticulturae 2024, 10(2), 149; https://doi.org/10.3390/horticulturae10020149 - 5 Feb 2024

Cited by 1 | Viewed by 1651

Abstract

Fruit size is an important factor for the sale of fruit in fresh markets. Fruit size prediction early in the growing season would help with planning harvest operations, administering marketing strategies and an advance determination of the proportion of fruit that will be [...] Read more.

Fruit size is an important factor for the sale of fruit in fresh markets. Fruit size prediction early in the growing season would help with planning harvest operations, administering marketing strategies and an advance determination of the proportion of fruit that will be suitable for certain size classes. Fruit diameter growth of ‘Keenan’ Valencia oranges was measured over five consecutive growing seasons (2014–2018) during Stage II (cell enlargement) and Stage III (maturation) periods between January and October. Fruits were randomly selected and tagged from around the tree canopy to record the fruit diameter at fortnightly intervals until harvest. The data were used to develop a fruit size prediction model using the cubic smoothing splines technique. Results indicated that from the fruit growth patterns, an accurate prediction of the final fruit size and distribution were possible during the early Stage II fruit development phase, 6–7 months ahead of the final harvest. It was concluded that fruit size must be 66 mm in diameter by 30 March to attain a fruit size > 77 mm at harvest. This model was tested in 2019 with an accuracy of 97% in predicting fruit size distribution harvest across three size classes. Full article

(This article belongs to the Special Issue An Update of the Crop Management Practices Enhancing Yield and Quality in Citrus)

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24 pages, 3012 KiB

Open AccessEditor’s ChoiceArticle

Variations in Essential Oil Composition and Chemotype Patterns of Wild Thyme (Thymus) Species in the Natural Habitats of Hungary

by Zsuzsanna Pluhár, Róbert Kun, Judit Cservenka, Éva Neumayer, Szilvia Tavaszi-Sárosi, Péter Radácsi and Beáta Gosztola

Horticulturae 2024, 10(2), 150; https://doi.org/10.3390/horticulturae10020150 - 5 Feb 2024

Cited by 4 | Viewed by 2418

Abstract

A comprehensive study was conducted on the diversity and characteristics of five Thymus species native to Hungary, concerning frequency of occurrence, habitat preferences, essential oil content of the dried flowering shoots, and chemotype patterns determined by GC/MS. Our main aims were to provide [...] Read more.

A comprehensive study was conducted on the diversity and characteristics of five Thymus species native to Hungary, concerning frequency of occurrence, habitat preferences, essential oil content of the dried flowering shoots, and chemotype patterns determined by GC/MS. Our main aims were to provide an overview of the essential oil diversity of thyme resources and select the best genotypes with potential for cultivation and utilization. Based on the results obtained in 74 populations of 63 localities belonging to 15 regions of the Transdanubian and Northern Hungarian Mountains, considerable essential oil diversity was found. Thymus pannonicus (TPA), of generalist character, was proven to be the most frequent species (38 populations), while T. serpyllum (TSE) occurred only in two habitats. High average amounts of essential oil (EO) were shown for T. pannonicus (0.46 mL/100 g DW), T. pulegioides (TPU: 0.47 mL/100 g DW), and T. serpyllum (0.59 mL/100 g DW), while low EO accumulating ability was detected in T. glabrescens (TGL: 0.26 mL/100 g DW) and in T. praecox (TPR: 0.10 mL/100 g DW). In general, the thymol chemotype was the most frequent (34 populations), found together with the related molecules (p-cymene: 26; γ-terpinene: 15), while numerous other monoterpenes (M: geraniol: 12, linalool: 7) or sesquiterpenes (S: germacrene D: 25, β-caryophyllene: 21) were dominant, as well as combined (MS) chemotypes, which were also described in the Eos of Thymus species in Hungary. Our findings confirmed that T. pannonicus shows potential for cultivation with homogenous drug quality, adequate amounts of essential oil, and stability in EO composition. Data from original habitats also supports its high tolerance and adaptability to diverse environmental conditions, which is advantageous when facing climate change and extremities. Full article

(This article belongs to the Special Issue Exploration of Medicinal Plants: Recent Advances and Future Perspectives)

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17 pages, 2027 KiB

Open AccessEditor’s ChoiceArticle

Inadequate Pollination Is a Key Factor Determining Low Fruit-to-Flower Ratios in Avocado

by María L. Alcaraz and Jose I. Hormaza

Horticulturae 2024, 10(2), 140; https://doi.org/10.3390/horticulturae10020140 - 31 Jan 2024

Cited by 4 | Viewed by 2109

Abstract

Avocado is an evergreen tree that exhibits protogynous dichogamy and displays a massive flower production, characterized by a high abscission of unfertilized flowers and developing fruitlets, ultimately leading to a low final fruit set. A common practice to improve avocado pollination involves introducing [...] Read more.

Avocado is an evergreen tree that exhibits protogynous dichogamy and displays a massive flower production, characterized by a high abscission of unfertilized flowers and developing fruitlets, ultimately leading to a low final fruit set. A common practice to improve avocado pollination involves introducing honey bee (Apis mellifera L.) hives during the flowering season. To evaluate the extent of inadequate pollination in avocado, the effect of different beehive densities on the percentage of flowers receiving pollen during the female flower stage was examined for seven years in an experimental orchard located in Southern Spain. A total of 17,288 flowers were observed under the microscope for this purpose. Additionally, pollen deposition was evaluated in five “Hass” avocado commercial orchards under different management strategies situated in the Malaga province (3960 flowers). The results obtained reveal that the percentage of flowers with pollen at the end of the female stage ranged from 2.85 (0.13% fruits retained at the end of June) in orchards without honey bee hives to 4.34 (0.11% fruits retained) in orchards in which 10 beehives per ha were placed. This percentage increased significantly to 13.79 after introducing 24 honey beehives per ha (0.21% fruits retained). Furthermore, the percentage of pollinated flowers in the commercial orchards remained below 15% even in those orchards in which pollen donors and honey bee hives were present. Thus, insufficient pollination could be considered as a primary limiting factor in avocado production under Mediterranean climates. Enhancing pollinator diversity and increasing their numbers could be a viable strategy to improve the percentage of avocado flowers receiving pollen during the female stage. Full article

(This article belongs to the Section Fruit Production Systems)

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26 pages, 1685 KiB

Open AccessEditor’s ChoiceArticle

Changes in Secondary Metabolite Production in Response to Salt Stress in Alcea rosea L.

by Arezoo Sadeghi, Jamshid Razmjoo, Hassan Karimmojeni, Timothy C. Baldwin and Andrea Mastinu

Horticulturae 2024, 10(2), 139; https://doi.org/10.3390/horticulturae10020139 - 31 Jan 2024

Cited by 6 | Viewed by 2140

Abstract

The effect of three levels of salinity on physio-biochemical traits in 10 Alcea rosea (hollyhock) varieties were evaluated. It was observed that salt stress increased both the total phenolic content (TPC) and total flavonoid content (TFC) in some varieties and decreased them in [...] Read more.

The effect of three levels of salinity on physio-biochemical traits in 10 Alcea rosea (hollyhock) varieties were evaluated. It was observed that salt stress increased both the total phenolic content (TPC) and total flavonoid content (TFC) in some varieties and decreased them in others. The greatest increases in both TPC and TFC were recorded in the Saman variety (104% and 62%, respectively) when cultivated under severe salt stress, indicating that this is the most salt-tolerant variety amongst those tested. The most abundant phenolic compound recorded was ellagic acid, and the phenolic compounds that showed the greatest increases in concentration due to salt stress were p-coumaric acid (87% in the Isfahan variety) and chlorogenic acid (142% in the Mahallat variety). Salt stress was also shown to decrease the production of diphenyl-2-picrylhydrazyl (DPPH) in all varieties. The highest concentration of DPPH (133%) was recorded in the Shiraz 1 variety, grown under conditions of severe salt stress. Salt stress also increased the mucilage content present in the petals, leaves, and seeds of some of the selected varieties. These data suggest that the selection of salt-tolerant varieties of hollyhock for direct cultivation or for use in future breeding programs is feasible. Full article

(This article belongs to the Section Biotic and Abiotic Stress)

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14 pages, 1802 KiB

Open AccessEditor’s ChoiceArticle

Role of Two Transcription Factors (TGA 1a and TGA 2.1) in the Mi-1-Mediated Resistance of Tomato to the Root-Knot Nematode Meloidogyne javanica

by Susana Pascual, Mariana Emiliozzi and Gloria Nombela

Horticulturae 2024, 10(2), 134; https://doi.org/10.3390/horticulturae10020134 - 30 Jan 2024

Cited by 5 | Viewed by 1940

Abstract

The Mi-1 gene in tomato confers resistance against insects and nematodes. The mechanisms involved in the functioning of this gene are not completely known, and they differ depending on the damaging organism (insect or nematode). Transcription factors (TF) from different families are essential [...] Read more.

The Mi-1 gene in tomato confers resistance against insects and nematodes. The mechanisms involved in the functioning of this gene are not completely known, and they differ depending on the damaging organism (insect or nematode). Transcription factors (TF) from different families are essential for plant defence, and the TGAs, members of the Basic Leucine Zipper (bZIP) TF family, are relevant in different pathosystems. In this work, the implication of TGA 1a and TGA 2.1 genes in Mi-1 resistance against the root-knot nematode Meloidogyne javanica was studied, by virus-induced gene silencing (VIGS) based on Tobacco rattle virus (TRV). Results showed that infiltration with the empty TRV vector did not alter Mi-1-mediated resistance, confirming the adequacy of this method. Silencing of the TGA 1a gene resulted in a decrease in resistance to M. javanica, as the numbers of egg masses were significantly higher than those on non-silenced plants. This decrease in resistance was similar to that caused by silencing the Mi-1 gene. However, the silencing of the TGA 2.1 gene caused a limited loss of resistance, with infestation levels intermediate between those of resistant and susceptible varieties. Thus, our results demonstrate the requirement of TGA 1a in Mi-1-mediated resistance to M. javanica, while the incomplete silencing of TGA 2.1 impaired a specific determination of its role. Full article

(This article belongs to the Special Issue Plant-Parasitic Nematodes in Horticultural Crops)

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16 pages, 3959 KiB

Open AccessEditor’s ChoiceArticle

Developing EST-SSR Markers for Identifying and Evaluating Asparagus Germplasm Resources Based on Transcriptome Sequences

by Dan Liu, Feili Yan, Changmei Liu, Aimeng Chen, Jiahui Wu, Ma Yu and Xiangyang Lyu

Horticulturae 2024, 10(2), 121; https://doi.org/10.3390/horticulturae10020121 - 26 Jan 2024

Cited by 4 | Viewed by 1782

Abstract

Radix asparagi is the dried root tuber of the Liliaceae plant Asparagus cochinchinensis (Lour.) Merr., which is a major Chinese medicinal herb with high medicinal and edible value in China. The planting area of A. cochinchinensis is extensive, and there is blind introduction [...] Read more.

Radix asparagi is the dried root tuber of the Liliaceae plant Asparagus cochinchinensis (Lour.) Merr., which is a major Chinese medicinal herb with high medicinal and edible value in China. The planting area of A. cochinchinensis is extensive, and there is blind introduction in various regions, leading to confusion the origin of Radix asparagi and impure germplasm. This study conducted morphological and karyotype analyses on cultivated Asparagus resources from seven main production areas in China and developed SSR molecular markers suitable for the identification of Asparagus germplasm resources based on the transcriptome sequencing results. The morphological results indicate that in addition to A. cochinchinensis (Lour.) Merr., recorded in the Pharmacopoeia of the People’s Republic of China, there are also A. taliensis Wang et Tang and A. lycopodineus (Baker) Wang et Tang cultivated in China. All the tested Asparagus resources were diploid and had 20 chromosomes. A total of 8841 single genes containing SSR loci were identified using transcriptome sequencing of Neijiang Asparagus, including 761 SSR loci with trinucleotide repeat units. One hundred pairs of SSR primers were randomly designed from the trinucleotide repeat loci for PCR and polymorphism verification, and ten pairs were selected for identification of Asparagus germplasm resources. The genetic diversity results of ten pairs of primers in seven Asparagus-producing regions were consistent with the morphological identification. This study provides technical support for the comprehensive evaluation and utilization of Asparagus germplasm resources. Full article

(This article belongs to the Special Issue Breeding, Cultivation, and Metabolic Regulation of Medicinal Plants)

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21 pages, 3125 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Predictive Model to Evaluate Water and Nutrient Uptake in Vertically Grown Lettuce under Mediterranean Greenhouse Conditions

by Manuel Felipe López Mora, María Fernanda Quintero Castellanos, Carlos Alberto González Murillo, Calina Borgovan, María del Carmen Salas Sanjuan and Miguel Guzmán

Horticulturae 2024, 10(2), 117; https://doi.org/10.3390/horticulturae10020117 - 25 Jan 2024

Cited by 5 | Viewed by 3226

Abstract

The decrease in arable land, water scarcity, and climate change increase the pressure on natural resources and agricultural production systems. In this context, agriculture must ensure food production for the rapidly growing and increasingly urban population of the world. Efforts must be made [...] Read more.

The decrease in arable land, water scarcity, and climate change increase the pressure on natural resources and agricultural production systems. In this context, agriculture must ensure food production for the rapidly growing and increasingly urban population of the world. Efforts must be made to obtain the highest yield from the unit area and promote the transition to more sustainable production systems Hydroponics is a modern growing technology mainly applied in greenhouses, which has developed rapidly over the past 30–40 years. Substrate-free hydroponic vertical crops (VC) can reduce the pressure conventional agriculture exerts on resources, saving water and nutrients, and increasing crop yields per unit area. Therefore, this study aimed to validate a proposed predictive model (PM) to simulate water and nutrient uptake in vertical crops under greenhouse conditions. On the basis of the Penman–Monteith equation, the PM estimates transpiration, while nutrient uptake was estimated using the Carmassi–Sonneveld submodel. The PM was experimentally evaluated for vertically grown lettuce under Mediterranean greenhouse conditions during spring 2023. The irrigation technique was a closed-loop fertigation circuit. The experiment consisted of testing two densities (50 and 80 plants·m⁻²) and three plant positions (low, medium, and upper). ANOVA (p < 0.05) and R² were used to evaluate the PM performance and crop behavior. The low density and the upper position had significantly higher mass values. The results suggest a high degree of performance for the PM, as the R² ranged from 0.7 to 0.9 for water and nutrient uptake. Both densities had a yield 17–20 times higher than conventional lettuce production and significant savings in water, about 85–88%. In this sense, the PM has great potential to intelligently manage VC fertigation, saving water and nutrients, which represents an advance toward reaching SDG 6 and SDG 12 within the 2030 Agenda. Full article

(This article belongs to the Special Issue Water and Fertilizer Management and Sustainable Use in Horticultural Production)

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15 pages, 4626 KiB

Open AccessEditor’s ChoiceArticle

Growth and Leaf Color of Coleus under Light Conditions Modified by Translucent Agrivoltaic Panels and Light-Emitting Diodes in a Greenhouse

by Suhyun Park, Jiseon Kim and Wook Oh

Horticulturae 2024, 10(2), 115; https://doi.org/10.3390/horticulturae10020115 - 24 Jan 2024

Cited by 2 | Viewed by 2651

Abstract

Dye-sensitized solar cells (DSSCs) can be used as greenhouse glazing materials in agrivoltaic systems because they are translucent, have different colors, and can produce electricity. However, the light quality of DSSCs differs from that of sunlight, and the visible light transmittance is low. [...] Read more.

Dye-sensitized solar cells (DSSCs) can be used as greenhouse glazing materials in agrivoltaic systems because they are translucent, have different colors, and can produce electricity. However, the light quality of DSSCs differs from that of sunlight, and the visible light transmittance is low. Therefore, we compared the plant shape, growth, and leaf color of coleus, a highly photosensitive plant, under transparent glass and red-colored DSSCs. Coleus ‘Highway Rose’ was grown in transparent (T, the control), shaded (S), and DSSC (D) chambers maintained at 23 ± 2 °C. The DSSC chambers were additionally illuminated with blue (B), green (G), white (W), B+G, and R+B+W light-emitting diodes (LEDs) (D+L) at 60 μmol·m⁻²·s⁻¹ photosynthetic photon flux density for 15 h from 05:00 to 20:00. The coleus generally exhibited good growth under the T treatment. However, the light quality of DSSCs differed from that of sunlight, and the visible light transmittance decreased. Coleus exhibited increased growth and leaf color characteristics under the supplemental B lighting treatments (D+L_(RBW), D+L_(B), D+L_(BG), and D+L_(W)). Supplemental lighting with B LEDs using DSSCs improved plant morphology growth and leaf color. On the other hand, supplemental G lighting reinforced the shade avoidance syndrome. Moreover, DSSCs could aid in reducing the energy required to control the environment. Full article

(This article belongs to the Section Protected Culture)

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17 pages, 2409 KiB

Open AccessEditor’s ChoiceArticle

Effects of Different Media and Their Strengths in In Vitro Culture of Three Different Cistus creticus L. Populations and Their Genetic Assessment Using Simple Sequence Repeat Molecular Markers

by Kostas Ioannidis and Polyxeni Koropouli

Horticulturae 2024, 10(1), 104; https://doi.org/10.3390/horticulturae10010104 - 22 Jan 2024

Cited by 2 | Viewed by 2030

Abstract

Cistus creticus L. (rockrose), a species of ecological and medicinal significance, constitutes a valuable component of the Mediterranean ecosystem. The present study investigated the effect of the inorganic salt concentration of Murashige and Skoog medium (MS), woody plant medium (WPM), and Driver and [...] Read more.

Cistus creticus L. (rockrose), a species of ecological and medicinal significance, constitutes a valuable component of the Mediterranean ecosystem. The present study investigated the effect of the inorganic salt concentration of Murashige and Skoog medium (MS), woody plant medium (WPM), and Driver and Kuniyaki Walnut medium (DKW) at several strengths (1/8×, 1/4×, 1/2×, 1×, and 2×) on the in vitro growth and organogenesis of rockrose. Significant interactions were observed throughout the experiments between pairs of plant origins, medium types, and strengths, and we also examined the extent to which they affected the studied traits was examined. The types of nutrient medium affected all studied traits except shoot and root percentages. The maximum growth percentage (143.49%) was gained using full-strength WPM. The best performance in shoot percentage was obtained using MS (100%) at several strengths along with 1× WPM (100%). The topmost rooting percentage values (98.61%) were obtained using 1× WPM and 1/2× DKW. The highest number of shoots and roots were observed using full-strength MS (9.39) and half-strength WPM (6.49), respectively. The maximum values for shoot and root length were achieved using 1/2× MS (0.78 cm) and 1/8× WPM (1.55 cm), respectively. The origin of the plant material did not influence any studied trait. Moreover, the genetic relations among the populations used in the in vitro culture were assessed using simple sequence repeats (SSR) markers. Twenty-eight alleles were identified across all five STR loci. The different and effective alleles per locus were 5.60 and 4.72, respectively. The average observed and expected heterozygosity was estimated at 0.52 and 0.72, respectively. Shannon’s information index and the inbreeding coefficient (F) were assessed at 1.48 and 0.30, respectively, revealing a narrow genetic base and high genetic similarity among origins, suggesting that they belong to the same population. Full article

(This article belongs to the Special Issue Seed Germination and Micropropagation of Ornamental Plants)

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11 pages, 11369 KiB

Open AccessEditor’s ChoiceArticle

Floral Biology of Aquilaria sinensis (Lour.) Spreng

by Bin Wang, Guangyao Ma, Suxian Lin, Xin He, Bo Chen, Haoling Li, Liangming Huang, Yun Yang and Jianhe Wei

Horticulturae 2024, 10(1), 109; https://doi.org/10.3390/horticulturae10010109 - 22 Jan 2024

Cited by 2 | Viewed by 2335

Abstract

Aquilaria sinensis (Lour.) Spreng is a known medicinal plant producing agarwood. To date, studies on the floral biology of A. sinensis have been limited. In this study, the floral micro- and ultra-structures, pollen viability, stigma receptivity, and artificial pollination of A. sinensis were [...] Read more.

Aquilaria sinensis (Lour.) Spreng is a known medicinal plant producing agarwood. To date, studies on the floral biology of A. sinensis have been limited. In this study, the floral micro- and ultra-structures, pollen viability, stigma receptivity, and artificial pollination of A. sinensis were investigated. The results show that the flower’s development can be divided into five stages, including the flower bud differentiation stage (2–7 d), the flower bud stage (7–13 d), the flowering stage (14 d), the pollination stage (14–15 d), and the fruiting stage (15–25 d). The floral organs mainly include: 4–6 split calyces, 10 petals, 10 stamens, and 1 pistil. The anther is oblong, with four pollen sacs the pollen is round, with maximum viability 6 h after flowering; and stigma receptivity is at its best 6 h before flowering. Artificial pollination is successful in the field. These findings will provide useful information for producing and breeding A. sinensis. Full article

(This article belongs to the Special Issue Breeding, Cultivation, and Metabolic Regulation of Medicinal Plants)

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17 pages, 7135 KiB

Open AccessEditor’s ChoiceArticle

Early Bruise Detection in Apple Based on an Improved Faster RCNN Model

by Jingli Hou, Yuhang Che, Yanru Fang, Hongyi Bai and Laijun Sun

Horticulturae 2024, 10(1), 100; https://doi.org/10.3390/horticulturae10010100 - 20 Jan 2024

Cited by 10 | Viewed by 2554

Abstract

Bruising is a common occurrence in apples that can lead to gradual fruit decay and substantial economic losses. Due to the lack of visible external features, the detection of early-stage bruising (occurring within 0.5 h) is difficult. Moreover, the identification of stems and [...] Read more.

Bruising is a common occurrence in apples that can lead to gradual fruit decay and substantial economic losses. Due to the lack of visible external features, the detection of early-stage bruising (occurring within 0.5 h) is difficult. Moreover, the identification of stems and calyxes is also important. Here, we studied the use of the short-wave infrared (SWIR) camera and the Faster RCNN model to enable the identification of bruises on apples. To evaluate the effectiveness of early bruise detection by SWIR bands compared to the visible/near-infrared (Vis/NIR) bands, a hybrid dataset with images from two cameras with different bands was used for validation. To improve the accuracy of the model in detecting apple bruises, calyxes, and stems, several improvements are implemented. Firstly, the Feature Pyramid Network (FPN) structure was integrated into the ResNet50 feature extraction network. Additionally, the Normalization-based Attention Module (NAM) was incorporated into the residual network, serving to bolster the attention of model towards detection targets while effectively mitigating the impact of irrelevant features. To reduce false positives and negatives, the Intersection over Union (IoU) metric was replaced with the Complete-IoU (CIoU). Comparison of the detection performance of the Faster RCNN model, YOLOv4P model, YOLOv5s model, and the improved Faster RCNN model, showed that the improved model had the best evaluation indicators. It achieved a mean Average Precision (mAP) of 97.4% and F1 score of 0.87. The results of research indicate that it is possible to accurately and effectively identify early bruises, calyxes, and stems on apples using SWIR cameras and deep learning models. This provides new ideas for real-time online sorting of apples for the presence of bruises. Full article

(This article belongs to the Special Issue Postharvest Handling and Nondestructive Detection of Fresh Horticulture Crops)

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23 pages, 1443 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Microbial Consortia Versus Single-Strain Inoculants as Drought Stress Protectants in Potato Affected by the Form of N Supply

by Abdullah Al Mamun, Günter Neumann, Narges Moradtalab, Aneesh Ahmed, Brice Dupuis, Geoffrey Darbon, Fahim Nawaz, Stephane Declerck, Karin Mai, Wolfgang Vogt, Uwe Ludewig and Markus Weinmann

Horticulturae 2024, 10(1), 102; https://doi.org/10.3390/horticulturae10010102 - 20 Jan 2024

Cited by 9 | Viewed by 3456

Abstract

This study investigated the drought protection effects of six fungal and bacterial inoculants and ten consortia thereof on vegetative growth, nutritional status, and tuberization of potato under controlled and field conditions. It was hypothesized that microbial consortia offer improved drought protection as compared [...] Read more.

This study investigated the drought protection effects of six fungal and bacterial inoculants and ten consortia thereof on vegetative growth, nutritional status, and tuberization of potato under controlled and field conditions. It was hypothesized that microbial consortia offer improved drought protection as compared with single strains, due to complementary or synergistic effects, with differential impacts also of N fertilization management. Under NO₃⁻ fertilization, a 70% reduction in water supply over six weeks reduced shoot and tuber biomass of non-inoculated plants by 30% and 50%, respectively, and induced phosphate (P) limitation compared to the well-watered control. The P nutritional status was significantly increased above the deficiency threshold by three single-strain inoculants and eight consortia. This was associated with the presence of the arbuscular mycorrhizal fungus (AMF) inoculant Rhizophagus irregularis MUCL41833 (five cases) and stimulation of root growth (five cases). Additionally, Bacillus amyloliquefaciens FZB42 and AMF + Pseudomonas brassicacearum 3Re2-7 significantly reduced irreversible drought-induced leaf damage after recovery to well-watered conditions. However, the microbial inoculants did not mitigate drought-induced reductions in tuber biomass, neither in greenhouse nor in field experiments. By contrast, NH₄⁺-dominated fertilization significantly increased tuber biomass under drought stress (534%), which was further increased by additional AMF inoculation (951%). This coincided with (i) improved enzymatic detoxification of drought-induced reactive oxygen species (ROS), (ii) improved osmotic adjustment in the shoot tissue (glycine betaine accumulation), (iii) increased shoot concentrations of ABA, jasmonic acid, and indole acetic acid, involved in drought stress signaling and tuberization, and (iv) reduced irreversible drought-induced leaf damage. Additional application of bacterial inoculants further improved ROS detoxification by increasing the production of antioxidants but stimulated biomass allocation towards shoot growth at the expense of tuber development. The results demonstrated that microbial consortia could increase the probability of drought protection effects influenced by the form of N supply. However, protective effects on vegetative growth do not necessarily translate into yield benefits, which can be achieved by adequate combination of inoculants and fertilizers. Full article

(This article belongs to the Special Issue Microbes and Plant Stress Tolerance)

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15 pages, 1357 KiB

Open AccessEditor’s ChoiceArticle

Identification of the Loci Associated with Resistance to Banana Xanthomonas Wilt (Xanthomonas vasicola pv. musacearum) Using DArTSeq Markers and Continuous Mapping

by Brigitte Uwimana, Gloria Valentine Nakato, Reagan Kanaabi, Catherine Nasuuna, Gerald Mwanje, George Simba Mahuku, Violet Akech, Marnik Vuylsteke, Rony Swennen and Trushar Shah

Horticulturae 2024, 10(1), 87; https://doi.org/10.3390/horticulturae10010087 - 16 Jan 2024

Cited by 3 | Viewed by 2124

Abstract

Banana Xanthomonas wilt, caused by Xanthomonas vasicola pv. musacearum (Xvm), is a devastating disease that results in total yield loss of affected plants. Resistance to the disease is limited in Musa acuminata, but it has been identified so far in [...] Read more.

Banana Xanthomonas wilt, caused by Xanthomonas vasicola pv. musacearum (Xvm), is a devastating disease that results in total yield loss of affected plants. Resistance to the disease is limited in Musa acuminata, but it has been identified so far in the zebrina subspecies. This study identified markers associated with tolerance to Xvm in Monyet, a tetraploid banana from the zebrina subspecies which was identified to be partially resistant to the bacterium. We used a triploid progeny of 135 F₁ hybrids resulting from a cross between Monyet (Xvm partially resistant) and Kokopo (diploid and Xvm susceptible). The F₁ hybrids were screened in pots for resistance to Xvm. The population was genotyped using the genotyping-by-sequencing platform of Diversity Array Technology (DArTSeq). The adjusted means of the phenotypic data were combined with the allele frequencies of the genotypic data in continuous mapping. We identified 25 SNPs associated with resistance to Xvm, and these were grouped into five quantitative traits loci (QTL) on chromosomes 2, 3, 6, and 7. For each marker, we identified the favorable allele and the additive effect of replacing the reference allele with the alternative allele. The comparison between weevil borer (Cosmopolites sordidus (Germar)) and Xvm QTL revealed one QTL shared between the two biotic stresses at the distal end of chromosome 6 but with a repulsion linkage. This linkage should be broken down by generating more recombinants in the region. We also identified 18 putative alleles in the vicinity of the SNPs associated with resistance to Xvm. Among the 18 putative genes, two particularly putative genes, namely, Ma06_g13550 and Ma06_g36840, are most likely linked to disease resistance. This study is a basis for marker-assisted selection to improve banana resistance to banana Xanthomonas wilt, especially in East and Central Africa where the disease is still devastating the crop. Full article

(This article belongs to the Special Issue Developments in the Genetics and Breeding of Banana Species)

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14 pages, 1400 KiB

Open AccessEditor’s ChoiceArticle

Chitosan Coating Incorporated with Carvacrol Improves Postharvest Guava (Psidium guajava) Quality

by Chang Shu, Beatrice Kim-Lee and Xiuxiu Sun

Horticulturae 2024, 10(1), 80; https://doi.org/10.3390/horticulturae10010080 - 14 Jan 2024

Cited by 13 | Viewed by 2771

Abstract

Guava (Psidium guajava L.) is an important economic crop grown widely in tropical and subtropical regions. Guava exhibits fast ripening and senescence as a climacteric fruit, causing a short shelf life and quality deterioration. Chitosan–essential oil nanoemulsions can be an edible coating [...] Read more.

Guava (Psidium guajava L.) is an important economic crop grown widely in tropical and subtropical regions. Guava exhibits fast ripening and senescence as a climacteric fruit, causing a short shelf life and quality deterioration. Chitosan–essential oil nanoemulsions can be an edible coating used to improve postharvest quality attributes. In this study, chitosan was mixed with carvacrol to generate a nano-emulsoid solution containing 0.1 and 0.2% (v/v) carvacrol, using a sonic dismembrator. Guava fruit were coated with the above emulsion and postharvest quality parameters were measured during storage at 20 ± 1 °C and RH = 80 ± 5% for 8 days. The result illustrated that the particle size of the chitosan–carvacrol emulsions was nanoscale, and their high stability was demonstrated by the zeta potential and polydispersity index. Chitosan coating (2%, w/v, 310–375 kDa) containing 0.2% (v/v) carvacrol maintained postharvest quality compared to chitosan alone, with higher firmness, soluble solid content, total acid, and total phenol content, and lower weight loss and pericarp browning. The collective data were further verified by principal component analysis. A chitosan coating containing carvacrol can reduce postharvest losses. It can be applied as an effective strategy to improve postharvest fruit quality. Full article

(This article belongs to the Special Issue Recent Advancements in Postharvest Fruit Quality and Physiological Mechanism)

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20 pages, 3211 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Study on Italian Onion Cultivars/Ecotypes towards Onion Yellow Dwarf Virus (OYDV) Infection

by Carla Libia Corrado, Giuseppe Micali, Antonio Mauceri, Sabrina Bertin, Francesco Sunseri, Maria Rosa Abenavoli and Antonio Tiberini

Horticulturae 2024, 10(1), 73; https://doi.org/10.3390/horticulturae10010073 - 11 Jan 2024

Cited by 1 | Viewed by 2285

Abstract

The onion yellow dwarf virus (OYDV) represents a limiting biotic stress in onion (Allium cepa L.); little information is available regarding resistant varieties. In Italy, onion production is limited but represented by a wide diversity of ecotypes. A two-year trial was carried [...] Read more.

The onion yellow dwarf virus (OYDV) represents a limiting biotic stress in onion (Allium cepa L.); little information is available regarding resistant varieties. In Italy, onion production is limited but represented by a wide diversity of ecotypes. A two-year trial was carried out to test the OYDV-susceptibility/tolerance of different Italian onion cultivars by rating symptom severity and plant growth parameters and assessing post-harvest secondary infections. The cultivar and ecotypes included in the study were characterized by simple sequence repeats (SSR) analysis, and the expression analysis of two genes (Eukaryotic translation initiation factors, EIFs) involved in potyvirus replication was also performed. Two susceptible and one tolerant cultivar were identified based on symptom expression and virus impact on plants. Although differences in growth parameters were limited to the first-year trial, the infection was correlated to a higher incidence of secondary infections in post-harvest, with altered water balance in infected bulbs. This correlation was also demonstrated during the long-term storage of bulbs. SSR analysis identified different clusters and only one gene isoform (EIF4eiso1) showed different expression levels in the OYDV/onion pathosystem. In conclusion, this study defines the genetic profile of Italian onion cultivars and provides evidence on susceptibility/tolerance features which will be useful in the future for the identification of viral resistance traits in onion. Full article

(This article belongs to the Special Issue Plant Pathology in Horticultural Production)

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28 pages, 3920 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Phytotoxicity in Untreated and Electrochemically Treated Leachates through the Analysis of Early Seed Growth and Inductively Coupled Plasma-Optical Emission Spectroscopy Characterization

by Alfredo Martínez-Cruz and María Neftalí Rojas-Valencia

Horticulturae 2024, 10(1), 67; https://doi.org/10.3390/horticulturae10010067 - 9 Jan 2024

Cited by 4 | Viewed by 2725

Abstract

The treatment of stabilized leachates with high refractory organic matter content, which are over 10 years old, presents a challenge. This study explored the potential of electro-coagulation (EC) and electro-oxidation (EO) treatment systems to address this issue. The objective of this study was [...] Read more.

The treatment of stabilized leachates with high refractory organic matter content, which are over 10 years old, presents a challenge. This study explored the potential of electro-coagulation (EC) and electro-oxidation (EO) treatment systems to address this issue. The objective of this study was to investigate the phytotoxicity of the proposed treatment system on seed growth and examine possible relationships between phytotoxicity results and the characterization of leachates, effluents, soil, and radicles. Phytotoxicity tests were conducted on seeds of Lactuca sativa, Cucumis sativus, and Phaseolus vulgaris, using Inductively Coupled Plasma-Optical analysis. The evolution of organic matter was monitored by fractionating the chemical oxygen demand (COD) and humic substances. The biodegradability index increased from 0.094 in raw leachate to 0.26 and 0.48 with EC and EO, respectively. Removal rates of 82%, 86%, 99%, and 81% were achieved for COD, dissolved organic carbon, color, and ammoniacal nitrogen, respectively. The biodegradable COD increased from 26% in raw leachate to 39% in the EC process and 58% in the EO process effluent. The proposed treatment system successfully broke the aromatic structures of the humic substances present in the raw leachate, thereby increasing the content of biodegradable material. Phytotoxicity tests revealed that the proposed treatment system significantly reduced the phytotoxicity of the generated effluents. Full article

(This article belongs to the Special Issue Advanced Studies in Abiotic Stress Response Mechanism of Horticultural Plants)

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21 pages, 7159 KiB

Open AccessEditor’s ChoiceArticle

Layout of Suspension-Type Small-Sized Dehumidifiers Affects Humidity Variability and Energy Consumption in Greenhouses

by Md Ashrafuzzaman Gulandaz, Md Sazzadul Kabir, Md Shaha Nur Kabir, Mohammod Ali, Md Nasim Reza, Md Asrakul Haque, Geun-Hyeok Jang and Sun-Ok Chung

Horticulturae 2024, 10(1), 63; https://doi.org/10.3390/horticulturae10010063 - 8 Jan 2024

Cited by 1 | Viewed by 2955

Abstract

In greenhouse management, maintaining optimal humidity is essential for promoting plant growth, including photosynthesis, and preventing diseases and pests. Addressing spatial variability requires sensor-based monitoring for informed decisions on humidification systems, particularly for small, and suspension-type dehumidifiers. This study aims to assess the [...] Read more.

In greenhouse management, maintaining optimal humidity is essential for promoting plant growth, including photosynthesis, and preventing diseases and pests. Addressing spatial variability requires sensor-based monitoring for informed decisions on humidification systems, particularly for small, and suspension-type dehumidifiers. This study aims to assess the impact of various layouts of small-sized suspension-type dehumidifiers on vertical, spatial, and temporal humidity variability, along with energy consumption in a greenhouse. During experiments in a 648 m³ (18 m × 6 m × 6 m) plastic greenhouse, dehumidifiers were placed at four different layouts: one at the center (Layout 1), one on each side (Layout 2), two units at the center facing opposite directions (Layout 3), and two units on one side facing the center (Layout 4). Temperature and humidity (TH) sensors were connected to a microcontroller, facilitating wireless data acquisition, storage, and remote monitoring. The actuator was controlled through a relay module, and current sensors monitored power consumption. Spatial interpolation and mapping were employed using mapping software. These layouts reduced humidity from 89.30% to 51.10%, with Layout 2 displaying the most consistent humidity distribution. Water removal efficiency varied among layouts, with Layout 2 exhibiting the highest (61.15 L) and overall performance of 50%, while Layouts 1, 3, and 4 exhibited lower efficiencies of 40%, 44%, and 49%, respectively. Power consumption ranged from 0.506 to 0.528 kW for the dehumidifier and 0.242 to 0.264 kW for the fan. The findings highlighted that positioning the dehumidifier on both sides, facing towards the center (Layout 2), resulted in the most uniform humidity control within the greenhouse. The optimal layout of small suspension-type dehumidifiers in greenhouses would significantly improve humidity control, promoting plant growth. Full article

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

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19 pages, 7095 KiB

Open AccessEditor’s ChoiceArticle

Whole-Transcriptome Sequencing Reveals That mRNA and ncRNA Levels Correlate with Pleurotus cornucopiae Color Formation

by Yingjie Zhang, Chenyang Huang, Mengran Zhao, Guangyu Li, Zeyin Wu, Jie Zhang and Lijiao Zhang

Horticulturae 2024, 10(1), 60; https://doi.org/10.3390/horticulturae10010060 - 7 Jan 2024

Cited by 1 | Viewed by 1709

Abstract

Pleurotus cornucopiae cap color is an important commercial trait. The roles of non-coding RNA molecules (ncRNAs) in fungal fruiting body color formation are unclear. Whole-transcriptome analyses were performed, identifying messenger RNA (mRNA) and ncRNA (including long stranded non-coding RNA (lncRNA), micro RNA-like (milRNA), [...] Read more.

Pleurotus cornucopiae cap color is an important commercial trait. The roles of non-coding RNA molecules (ncRNAs) in fungal fruiting body color formation are unclear. Whole-transcriptome analyses were performed, identifying messenger RNA (mRNA) and ncRNA (including long stranded non-coding RNA (lncRNA), micro RNA-like (milRNA), and circular RNA (circRNA)) molecules in three P. cornucopiae strains with different cap colors (grayish-black, grayish-white, and white), to investigate their roles in cap color formation. Differentially expressed mRNAs (n = 3604), lncRNAs (n = 520), milRNAs (n = 56), and circRNAs (n = 20) were identified among the three different color strains. Differentially expressed mRNAs and ncRNAs target genes were mainly involved in tyrosine, arachidonic acid, and histidine metabolism, plus other pathways potentially important in color formation. A competitive endogenous RNA (ceRNA) network and three mRNA and ncRNA co-expression networks were constructed, revealing relationships contributing to cap color formation, involving genes with roles in protein phosphorylation, and phenylalanine, tyrosine, and tryptophan biosynthesis. qRT-PCR analysis confirmed that mRNA and ncRNA levels were related to P. cornucopiae color. These regulatory networks may be crucial in P. cornucopiae color formation. Our data provide a new perspective to support further study of the mechanisms underlying P. cornucopiae color formation. Full article

(This article belongs to the Section Medicinals, Herbs, and Specialty Crops)

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