Genomics and molecular breeding in lesser explored pulse crops: Current trends and future opportunities

Pulses are multipurpose crops for providing income, employment and food security in the underprivileged regions, notably the FAO-defined low-income food-deficit countries. Owing to their intrinsic ability to endure environmental adversities and the least input/management requirements, these crops remain central to subsistence farming. Given their pivotal role in rain-fed agriculture, substantial research has been invested to boost the productivity of these pulse crops. To this end, genomic tools and technologies have appeared as the compelling supplement to the conventional breeding. However, the progress in minor pulse crops including dry beans (Vigna spp.), lupins, lablab, lathyrus and vetches has remained unsatisfactory, hence these crops are often labeled as low profile or lesser researched. Nevertheless, recent scientific and technological breakthroughs particularly the next generation sequencing (NGS) are radically transforming the scenario of genomics and molecular breeding in these minor crops. NGS techniques have allowed de novo assembly of whole genomes in these orphan crops. Moreover, the availability of a reference genome sequence would promote re-sequencing of diverse genotypes to unlock allelic diversity at a genome-wide scale. In parallel, NGS has offered high-resolution genetic maps or more precisely, a robust genetic framework to implement whole-genome strategies for crop improvement. As has already been demonstrated in lupin, sequencing-based genotyping of the representative sample provided access to a number of functionally-relevant markers that could be deployed straight away in crop breeding programs. This article attempts to outline the recent progress made in genomics of these lesser explored pulse crops, and examines the prospects of genomics assisted integrated breeding to enhance and stabilize crop yields.     

Screening and identification of random amplified polymorphic DNA (RAPD) markers linked to mungbean yellow mosaic virus (MYMV) resistance in mungbean (Vigna radiata (L.) Wilczek)

Bulk segregant analysis (BSA) and random amplified polymorphic DNA (RAPD) techniques were used to analyse the F2 individuals of susceptible VBN (Gg) 2 × resistant KMG 189 to screen and identify the molecular marker linked to mungbean yellow mosaic virus (MYMV) resistant gene in mungbean. Two DNA bulks namely resistant bulks and susceptible bulks were setup by pooling equal amount of DNA from five randomly selected plants of each disease response. A total of 72 random sequence decamer oligonucleotide primers were used for RAPD analysis. Primer OPBB 05 (5′-GGGCCGAACA-3′) generated OPBB 05 260 fragment in resistant parent and their bulks but not in the susceptible parent and their bulks. Co segregation analysis was performed in resistant and susceptible F2 individuals, it confirmed that OPBB 05 260 marker was tightly linked to mungbean yellow mosaic virus resistant gene in mungbean.