Mungbean Wild Genetic Resource: A Potential Source of Genetic Improvement for Biotic and Abiotic Stress Tolerance

Abstract Lentil is an important cool season food legume being grown over a large area in the world. Keeping in view its increasing demand, efforts are underway to improve its plant type having high yielding ability, resistance/tolerance to biotic and abiotic stresses. Most of the existing varieties have been developed through hybridization and pure line selection within Lens culinaris ssp. culinaris, leading to narrow genetic base, stagnant yielding potential, and susceptibility to biotic (diseases, insect pests) and abiotic (winter hardiness, heat, drought, salinity, waterlogging, herbicide) stresses. As greater genetic variability has been observed in wild relatives, therefore, distant hybridization involving wild accessions from L. culinaris ssp. orientalis, L. nigricans, L. ervoides, L. odemensis, L. culinaris ssp. tomentosus L. lamottei not only increases genetic variability but also helps in transfer of desirable traits making cultivated lentil more usable. Attempts have been made at different research institutions to evaluate lentil wild genetic resources for key biotic and abiotic stresses. Wild gene pool of lentil (L. ervoides, L. nigricans, and L. culinaris ssp. orientalis) showed tolerance against drought and cold stresses. Some of the wild accessions (ILWL 138, ILWL 37, and ILWL 77) with multiple disease resistance have also been identified. Reproductive isolation, cross incompatibility, embryo abortion, hybrid sterility, and limited level of genetic recombination are some constraints in using these resources in lentil breeding programs at a larger extent. A better understanding of the crossability, post fertilization barriers, embryo rescue technique, and use of growth hormones has enhanced the possibilities of using these wild resources. However, a lot still requires to be done in genetic transformation of lentil for gene transfer across genome boundaries.