Genome Research in Mungbean [V igna radiata (L.) Wilczek] and Blackgram [ V. mungo (L.) Hepper]

A BSTRACT : Mungbean [ Vigna radiata (L.) Wilczek] and blackgram [ V. mungo (L.) Hepper] (both 2n=2x=22) are important legume crops in Asia, which serve their roles as cash crops for farmers and as protein sources for consumers. Genome research in mungbean has long been conducted before blackgram and six genetic linkage maps were developed so far but no map contained enough markers to condense into 11 putative linkage groups. While only one linkage map was constructed for blackgram and resolved all 11 linkage groups. Thus mungbean is considered one of the most recalcitrant crops in genomic research. Comparative genome mapping between mungbean and several other legumes including azuki bean, common bean, cowpea, soybean, lablab and Medicago trunculata revealed various levels of macrosynteny depending on species, with the greatest upon common bean. Comparison between blackgram and azuki bean maps revealed high degree of genome colinearity. Genes or quantitative trait loci for several important traits were identified in mungbean compared to only one in blackgram. Improved genetic transformation protocols for the crops have been developed recently. High-throughput markers such as SSRs and SNPs developed for closely related legumes with mungbean and blackgram will be helpful to accelerate genome research and molecular breeding in these crops.