Protecting Crops against Diseases and Pests Using Resistance From New Sources of Germplasm.

Pathogens and insect pest biotypes/races evolve dynamically in response to selection pressure exerted by nature and crop agro-ecosystems and cause yield loss globally. To meet future food requirements of the growing population amidst diminishing resources and unpredictable climate, continued infusion of new genetic diversity needs to be one of the key elements in future crop improvement strategies. A dynamic crop improvement program using genetically diverse sources of resistance from a large pool of cultivated germplasm and wild and weedy crop relatives conserved in genebanks ensures effective safeguards against various biotic stresses. However, evaluation of the large germplasm collections against diverse populations of diseases and insect pests is resource intensive and time consuming. The development of core (10% of the entire collection) and mini core (1% of the entire collection) collections in such cases allows researchers to identify new sources of resistance to diseases and pests in smaller representative subsets through extensive evaluation. At ICRISAT we have used mini core approach to identify new sources of resistance to various diseases in chickpea, groundnut, pigeonpea, and sorghum. The crop wild and weedy relatives are particularly beneficial when levels of resistance are low in cultivated germplasm, and we need to access the novel alleles from distant genepools. Sources for resistance in the wild genepool of chickpea, pigeonpea, groundnut, sorghum and pearl millet have been identified for key diseases and insect pests.