A large-effect QTL introgressed from ricebean imparts resistance to Mungbean yellow mosaic India virus in blackgram (Vigna mungo (L.) Hepper).

KEY MESSAGE: Here, we report identification of a large effect QTL conferring Mungbean yellow mosaic India virus resistance introgressed from ricebean in blackgram variety Mash114. The tightly linked KASP markers would assist in marker-assisted-transfer of this region into Vigna species infected by MYMIV. Until recently, precise location of genes and marker-assisted selection was long thought in legumes such as blackgram due to lack of dense molecular maps. However, advances in next-generation sequencing based on high-throughput genotyping technologies such as QTL-seq have revolutionized trait mapping in marker-orphan crops. Using QTL-seq approach, we have identified a large-effect QTL for resistance to Mungbean yellow mosaic India virus (MYMIV) in blackgram variety Mash114. MYMIV is devastating disease responsible for huge yield losses in blackgram, greengram and other legumes. Mash114 showed consistent and high level of resistance to MYMIV since last nine years. Whole genome re-sequencing of MYMIV-resistant and susceptible bulks derived from RILs of cross KUG253 X Mash114 identified a large-effect QTL (qMYMIV6.1.1) spanning 3.4 Mb on chromosome 6 explaining 70% of total phenotypic variation. This region was further identified as an inter-specific introgression from ricebean. Linkage mapping using KASP markers developed from potent candidate genes involved in virus resistance identified the 500 kb genomic region equaling 1.9 cM on genetic map linked with MYMIV. The three KASP markers closely associated with MYMIV originated from serine threonine kinase, UBE2D2 and BAK1/BRI1-ASSOCIATED RECEPTOR KINASE genes. These KASPs can be used for marker-assisted transfer of introgressed segment into suitable backgrounds of Vigna species.

Genome-wide Association Study for Yield and Yield-Related Traits in Diverse Blackgram Panel (Vigna mungo L. Hepper) Reveals Novel Putative Alleles for Future Breeding Programs.

Blackgram (Vigna mungo L. Hepper) is an important tropical and sub-tropical short-duration legume that is rich in dietary protein and micronutrients. Producing high-yielding blackgram varieties is hampered by insufficient genetic variability, absence of suitable ideotypes, low harvest index and susceptibility to biotic-abiotic stresses. Seed yield, a complex trait resulting from the expression and interaction of multiple genes, necessitates the evaluation of diverse germplasm for the identification of novel yield contributing traits. Henceforth, a panel of 100 blackgram genotypes was evaluated at two locations (Ludhiana and Gurdaspur) across two seasons (Spring 2019 and Spring 2020) for 14 different yield related traits. A wide range of variability, high broad-sense heritability and a high correlation of grain yield were observed for 12 out of 14 traits studied among all environments. Investigation of population structure in the panel using a set of 4,623 filtered SNPs led to identification of four sub-populations based on ad-hoc delta K and Cross entropy value. Using Farm CPU model and Mixed Linear Model algorithms, a total of 49 significant SNP associations representing 42 QTLs were identified. Allelic effects were found to be statistically significant at 37 out of 42 QTLs and 50 known candidate genes were identified in 24 of QTLs.

Developments and Prospects in Imperative Underexploited Vegetable Legumes Breeding: A Review.

Vegetable legumes are an essential source of carbohydrates, vitamins, and minerals, along with health-promoting bioactive chemicals. The demand for the use of either fresh or processed vegetable legumes is continually expanding on account of the growing consumer awareness about their well-balanced diet. Therefore, sustaining optimum yields of vegetable legumes is extremely important. Here we seek to present d etails of prospects of underexploited vegetable legumes for food availability, accessibility, and improved livelihood utilization. So far research attention was mainly focused on pulse legumes' performance as compared to vegetable legumes. Wild and cultivated vegetable legumes vary morphologically across diverse habitats. This could make them less known, underutilized, and underexploited, and make them a promising potential nutritional source in developing nations where malnutrition still exists. Research efforts are required to promote underexploited vegetable legumes, for improving their use to feed the ever-increasing population in the future. In view of all the above points, here we have discussed underexploited vegetable legumes with tremendous potential; namely, vegetable pigeon pea (Cajanus cajan), cluster bean (Cyamopsis tetragonoloba), winged bean (Psophocarpus tetragonolobus), dolichos bean (Lablab purpureus), and cowpea (Vigna unguiculata), thereby covering the progress related to various aspects such as pre-breeding, molecular markers, quantitative trait locus (QTLs), genomics, and genetic engineering. Overall, this review has summarized the information related to advancements in the breeding of vegetable legumes which will ultimately help in ensuring food and nutritional security in developing nations.