Utilization of Advanced Backcross Population Derived from Synthetic Amphidiploid for Dissecting Resistance to Late Leaf Spot in Peanut (Arachis hypogaea L.)

Late leaf spot (LLS) is the major foliar disease, which often occur with rust and cause severe yield losses worldwide in peanut (Arachis hypogaea L.). In order to map and introgress the resistance alleles for LLS into an elite cultivar ICGS 76, the advanced backcross approach was used for identification of quantitative trait locus (QTL). The synthetic amphidiploid ISATGR 278-18 (A. duranensis ICG 8138 x A. batizocoi ICG 13160) which is known to harbor resistance alleles for foliar diseases was used as donor parent to generate AB-QTL population comprising of 164 introgression lines (ILs). A linkage map with 114 microsatellite markers was developed spanning 746.15 cM distance with an average inter-marker distance of 6.55 cM. QTL analysis yielded 14 main-effect QTLs (mQTLs) (explaining up to 38.58% PVE) for LLS and 10 mQTLs (up to 10.99% PVE) for rust. In addition, four epistatic QTLs (eQTLs) (explaining up to 4.97% PVE) were observed for foliar diseases. Furthermore, seven mQTLs and 16 eQTLs were observed for agronomic traits. Several ILs showed high resistance to LLS with agronomic attributes from recurrent parent. This study reports the utilization of the untapped resistance source for LLS from A. batizocoi that was not extensively used earlier in peanut crop improvement.