Quantitative Trait Loci for Disease and Insect Pest Resistance and Grain Quality in Mungbean (Vigna radiata (L.) Wilczek)

Mungbean (Vigna radiata (L.) Wilczek) is a short-duration legume crop. In South and East Asia it is usually planted as an intercrop in the annual rice-wheat double cropping system. Mungbean provides protein- and iron-rich seeds that serve as nutritious food. Its nitrogen-fixing properties improve soil fertility and the decomposing biomass improves soil texture, leading to increases in yield in subsequent cereal crops. Mungbean productivity and profitability in Asia is limited mainly by whitefly-transmitted Mungbean yellow mosaic India virus (MYMIV) and insect pests such as bruchids (Callosobruchusspp.). Breeding to introgress resistance against these pests into adapted and high yielding mungbean varieties is ongoing in several Asian countries.

A genetic linkage map making use of several different marker systems has been constructed to enable molecular breeding approaches for mungbean crop improvement. Four quantitative trait loci for MYMIV resistance and three for bruchid resistance have been mapped in an F₁₂ recombinant inbred line population derived from a cross between V. radiata x V. radiata subsp. sublobata. Additionally, quantitative trait loci for seed size and seed germination rate were identified. Markers delimiting these loci are available for marker-assisted selection.

A major bottleneck for mungbean molecular breeding is the lack of polymorphic markers for this crop. RAD-Tag sequencing efforts and development of a single nucleotide polymorphism (SNP) genotyping tool for mungbean are ongoing to provide sufficient polymorphic markers for trait mapping and marker-assisted selection in V. radiata breeding populations.