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Plant breeders develop competitive, high-yielding, resistant crop varieties that can cope with the challenges of biotic stresses and tolerate abiotic stresses, resulting in nutritious food for consumers worldwide. To achieve this, plant breeders need continuous and easy access to plant genetic resources (PGR) for trait screening, to generate new diversity that can be built into newly improved varieties. International agreements such as the Convention on Biological Diversity (CBD), the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) and the Nagoya Protocol recognised the sovereign rights of countries over their genetic resources. Under the CBD/Nagoya Protocol, countries are free to establish specific national legislations regulating germplasm access and benefit-sharing to be negotiated bilaterally. Consequently, access to PGR became increasingly restricted and cumbersome, resulting in a decrease in germplasm exchange. The ITPGRFA attempted to ease this situation by establishing a globally harmonised multilateral system (MLS). Unfortunately, the MLS is (still) restricted to a limited number of food and forage crops, with very few vegetable crops. Easy and continuous access to genetic diversity combined with equitable and fair sharing of derived benefits is a prerequisite to breeding new varieties. Facilitated access contributes to sustainable crop production and food and nutrition security; therefore, access to and, consequently, use of PGRFA needs to be improved. Thus, the authors recommend, among others, expanding the scope of the ITPGRFA to include all PGRFA and making them and all related information accessible under a Standard Material Transfer Agreement (SMTA) combined, if necessary, with a subscription system or a seed sales tax. Such a transparent, functional and efficient system would erase legal uncertainties and minimise transaction costs for conservers, curators and users of genetic resources, thus aiding plant breeders to fulfil their mission. [ABSTRACT FROM AUTHOR]

Flowering time is an important target for breeders in developing new varieties adapted to changing conditions. In this work, a new approach is proposed in which the SNP markers influencing time to flowering in mung bean are selected as important features in a random forest model. The genotypic and weather data are encoded in artificial image objects, and a model for flowering time prediction is constructed as a convolutional neural network. The model uses weather data for only a limited time period of 5 days before and 20 days after planting and is capable of predicting the time to flowering with high accuracy. The most important factors for model solution were identified using saliency maps and a Score-CAM method. Our approach can help breeding programs harness genotypic and phenotypic diversity to more effectively produce varieties with a desired flowering time. [ABSTRACT FROM AUTHOR]

Flowering time is an important target for breeders in developing new varieties adapted to changing conditions. A new approach is proposed that uses Approximate Bayesian Computation with Differential Evolution to construct a pool of models for flowering time. The functions for daily progression of the plant from planting to flowering are obtained in analytic form and depend on daily values of climatic factors and genetic information. The resulting pool of models demonstrated high accuracy on the dataset. Day length, solar radiation and temperature had a large impact on the model accuracy, while the impact of precipitation was comparatively small and the impact of maximal temperature has the maximal variation. The model pool was used to investigate the behavior of accessions from the dataset in case of temperature increase by 0.05 – 6.00 ° . The time to flowering changed differently for different accessions. The Pearson correlation coefficient between the SNP value and the change in time to flowering revealed weak but significant association of SNP7 with behavior of the accessions in warming climate conditions. The same SNP was found to have a considerable influence on model prediction with a permutation test. Our approach can help breeding programs harness genotypic and phenotypic diversity to more effectively produce varieties with a desired flowering time. [ABSTRACT FROM AUTHOR]

The Squash Leaf Curl China Virus (SLCCNV) and Tomato Leaf Curl New Delhi Virus (ToLCNDV) are species of Begomovirus (whitefly-vectored Geminiviridae) and cause serious damage to the cucurbit crops of the genus Cucurbita in the areas of South and Southeast Asia, across Asia, the Middle East and the Mediterranean, respectively. Cucurbita moschata's inbred line AVPU1426, developed at the World Vegetable Center (WorldVeg) from a Bangladeshi landrace through pedigree selection, was observed to be resistant to both begomoviruses in field tests conducted at the WorldVeg Research and Training Station, Kasetsart University, Kamphaeng Saen, Thailand, which is a hotspot for these viruses. When AVPU1426 was tested for reaction to inoculation by viruliferous whiteflies with Squash Leaf Curl Philippines Virus (Taiwan strain) (SLCPV-TW) in the screen net-house at WorldVeg headquarters in Taiwan, it showed good resistance, though SLCPV-TW DNA-A could be detected in all inoculated plants, indicating that it did not show immunity to this virus. The objective of this study was to validate the resistance to SLCCNV and ToLCNDV in AVPU1426 by using whitefly-mediated inoculations to determine the mode of inheritance of the resistance. The results showed that AVPU1426 was resistant to SLCCNV and ToLCNDV. Upon crossing AVPU1426 with a susceptible check variety, Waltham Butternut, the resistance to both begomoviruses was observed to be conferred by a single recessive gene. This open-pollinated pumpkin line AVPU1426 bears flat round, mottled green immature fruits with yellow flesh in mature fruit. The fruit yield of AVPU1426 (20.74 t/ha−1) was comparable to 'Rajah' (18.61 t/ha−1), a recently released commercial F1 hybrid of East-West Seed (EWS). The fruit of AVPU1426 were estimated to have a good average β-carotene content (1.57 mg/100 g fresh weight). This line is a good source to breed pumpkins resistant to the three begomoviruses. [ABSTRACT FROM AUTHOR]

Okra (Abelmoschus esculentus) is a heat tolerant vegetable crop with high economic and nutritional importance in parts of Asia, Africa, and America. The okra biodiversity held in gene bank collections could be mined for traits for breeding more stress tolerant and nutritional cultivars. An okra core collection of 166 accessions comprising A. esculentus, A. moschatus, A. caillei, and A. manihot has been assembled from the World Vegetable Center germplasm collection (840 accessions) based on diversity analysis with 20 microsatellite markers. A selection of A. esculentus accessions of the core collection (75 accessions) and 20 breeder-selected genotypes have been screened for variation of their response to flooding stress under field conditions using a high throughput phenotyping system. Growth increment per day and changes of physiological indices were measured before, during, and after application of 9 days of flooding stress. Several accessions showed only a small reduction in daily growth increment during flooding. Across the germplasm panel, maintained growth was correlated with maintained normalized differential vegetation index and was negatively correlated with plant senescence index. Accessions with maintained growth and health under flooding were selected for future further analysis and use in breeding. [ABSTRACT FROM AUTHOR]

The mission of the World Vegetable Center (WorldVeg) is research and development to realize the potential of vegetables for healthier lives and more resilient livelihoods. WorldVeg operates across Asia and Africa, and its breeding portfolio comprises global as well as traditional vegetables. Cucurbit crops make an important contribution to global food and nutrition security and are economically important to smallholder farmers in Asia, who account for 83% of global cucurbit production. The global cucurbit breeding program of WorldVeg focuses on four species: bitter gourd (Momordica charantia), tropical pumpkin (Cucurbita moschata), ridge gourd (Luffa acutangula), and sponge gourd (Luffa cylindrica syn. L. aegyptiaca). Improved cultivars have been developed by the private seed industry, however, repeated recycling of lines derived from elite hybrids has narrowed the genetic base and reduced genetic gains for yield and other key traits. This trend will continue unless a concerted effort is made to introduce new genetic variability into elite hybrids. WorldVeg has organized a breeding consortium with seed companies to facilitate access to the Center's new breeding lines derived from hitherto unexploited landraces to develop genetically diverse, improved cucurbit cultivars with enhanced yield and resistance to major diseases. Through this partnership, WorldVeg presents its improved lines and F1 hybrids at Crop Field Days for selection by private seed industry staff engaged in breeding, product development, and sales and marketing. [ABSTRACT FROM AUTHOR]

Mungbean (Vigna radiata (L.) R. Wilzeck var. radiata) is a protein-rich short-duration legume that fits well as a rotation crop into major cereal production systems of East and South-East Asia. Salinity stress in arid areas affects mungbean, being more of a glycophyte than cereals. A significant portion of the global arable land is either salt or sodium affected. Thus, studies to understand and improve salt-stress tolerance are imminent. Here, we conducted a genome-wide association study (GWAS) to mine genomic loci underlying salt-stress tolerance during seed germination of mungbean. The World Vegetable Center (WorldVeg) mungbean minicore collection representing the diversity of mungbean germplasm was utilized as the study panel and variation for salt stress tolerance was found in this germplasm collection. The germplasm panel was classed into two agro-climatic groups and showed significant differences in their germination abilities under salt stress. A total of 5288 SNP markers obtained through genotyping-by-sequencing (GBS) were used to mine alleles associated with salt stress tolerance. Associated SNPs were identified on chromosomes 7 and 9. The associated region at chromosome 7 (position 2,696,072 to 2,809,200 bp) contains the gene Vradi07g01630, which was annotated as the ammonium transport protein (AMT). The associated region in chromosome 9 (position 19,390,227 bp to 20,321,817 bp) contained the genes Vradi09g09510 and Vradi09g09600, annotated as OsGrx_S16-glutaredoxin subgroup II and dnaJ domain proteins respectively. These proteins were reported to have functions related to salt-stress tolerance. [ABSTRACT FROM AUTHOR]

Agricultural scientists face the dual challenge of breeding input-responsive, widely adoptable and climate-resilient varieties of crop plants and developing such varieties at a faster pace. Integrating the gains of genomics with modern-day phenomics will lead to increased breeding efficiency which in turn offers great promise to develop such varieties rapidly. Plant phenotyping techniques have impressively evolved during the last two decades. The low-cost, automated and semi-automated methods for data acquisition, storage and analysis are now available which allow precise quantitative analysis of plant structure and function; and genetic dissection of complex traits. Appropriate plant types can now be quickly developed that respond favorably to low input and resource-limited environments and address the challenges of subsistence agriculture. The present review focuses on the need of systematic, rapid, minimal invasive and low-cost plant phenotyping. It also discusses its evolution to modern day high throughput phenotyping (HTP), traits amenable to HTP, integration of HTP with genomics and the scope of utilizing these tools for crop improvement. [ABSTRACT FROM AUTHOR]