Diversification of primary gene pool through introgression of resistance to foliar diseases from synthetic amphidiploids to cultivated groundnut (Arachis hypogaea L.)

Groundnut (Arachis hypogaea L.) is widely grown and consumed around the world and is considered to have originated from a single hybridization event between two wild diploids. The utilization of wild germplasm in breeding programs has been restricted by reproductive barriers between wild and cultivated species and technical difficulties in making large numbers of crosses. Efforts to overcome these hurdles have resulted in the development of synthetic amphidiploids, namely ISATGR 278-18 (Arachis duranesis × Arachis batizocoi) and ISATGR 5B (Arachis magna × A. batizocoi), which possess several desirable traits, including resistance to foliar diseases that generally cause huge yield losses annually in groundnut growing areas of Asia, America, and Africa. With an objective to improve foliar disease resistance, the primary gene pool was diversified by introgressing foliar disease resistance in five cultivated genotypes (ICGV 91114, ICGS 76, ICGV 91278, JL 24, and DH 86) from synthetic amphidiploids using a backcross breeding approach. Several introgression lines with resistance to two foliar diseases (rust and late leaf spot) were identified with levels of resistance equal to the donors. These backcross derived lines have shown a wide range of variation for several morphological and agronomic traits. These lines, after further evaluation and selection, can serve as donors in future breeding programs aimed at developing improved cultivars with desirable agronomic traits, high resilience to biotic/abiotic stresses and a broadened genetic base.