Identification of major consensus and epistatic QTLs for late leaf spot resistance in a cultivated groundnut breeding line VG 9514

A late leaf spot resistant breeding line VG 9514 was bred through interspecific hybridization between Arachis hypogaea L. and Arachis cardenasii . Genetic study involving segregation for late leaf spot resistance in 164 F 2 and recombinant inbred line populations derived from a cross between VG 9514 X TAG 24 revealed duplicate recessive resistance for the disease. Integration of newly developed SSR markers from A02 chromosome with existing linkage map generated a new genetic linkage map with 278 markers and 2679.1 cM map distances. QTL mapping involving this genetic linkage map and phenotypic field score of late leaf spot identified two major consensus additive QTLs in the A02 chromosome of cultivated groundnut. Epistatic interaction between these two major QTLs was also noticed through an epistatic QTL analysis in Ici-Mapping 4.1. In all the fourteen epistatic QTLs, a common component locus was remained within the major additive QTL at 90 cM in chromosome A02. Sequence analysis within the major additive QTL peaks revealed open reading frame of genes that code LRR domain containing proteins which are involved in disease resistance of crop plants.