A novel QTL governing resistance to stem rot disease caused by Sclerotium rolfsii in peanut

Abstract

Stem rot disease caused by Sclerotium rolfsii is limiting the peanut production worldwide. Linkage analysis and QTL mapping for resistance to stem rot disease was done in a biparental F2 population developed from a susceptible cultivar GG 20 and a resistant interspecific prebreeding line CS 19 using 1980 simple sequence repeat markers. Only 25.5 % primers were found polymorphic between parents. Among polymorphic primers 23 could differentiate homozygotes and F1 heterozygotes and were carried forward for the genotyping of 178 F2 progenies. Out of which 12 primers segregated in expected 1:2:1 ratio while rest segregated in a distorted ratio. Upon comparison with the international consensus map of peanut 22 markers are found anchored markers of 20 linkages except AHS1480. In this study a total map distance of 558.74 cM is covered by 12 marker loci in two linkage groups. Here we report AHS1480 as a new marker to the existing international consensus peanut linkage map. In this studies a major QTL qstga01.1 is identified for resistance to stem rot disease in peanut which is contributed by resistant parent. Both flanking markers GM2350 and TC4H02 are tightly linked to the major QTL. To our understanding this is the first report on QTL for resistance to stem rot disease in peanut.