Molecular tagging and mapping of resistance to late leaf spot and rust in ground nut Archis hypogea L

Abstract

Groundnut (Arachis hypogaea L.) is an important oilseed crop of the world. Late leaf newlinespot (Phaeoisariopsis personata [(Berk. and Curt.) Deighton] and rust (Puccinia arachidis newlineSpeg.) are the major destructive diseases of the crop. The use of resistant cultivars is the newlinepreferred strategy to surmount the losses but resistance breeding has not been completely newlinesuccessful. Molecular dissection of resistance traits using QTL analysis can improve the newlineefficiency of resistance breeding. newlineThe present study was aimed at construction of genetic linkage map, identification of newlinemarkers / QTL associated with resistance to LLS and rust besides various yield related traits. newlineTwo hundred and sixty eight RILs (TAG 24 × GPBD 4) segregating for late leaf spot and rust newlinewere used to undertake QTL analysis. Phenotyping of the population was carried out under newlineartificial disease epiphytotics. Parents were assessed using 1089 SSR markers, of them 67 newline(6.15%) were found polymorphic. Single marker analysis revealed 34 markers associated with newlineLLS (1.12 to 5.78%) and 11 markers with rust (1.26 to 40.58%). Among the agronomic traits, newline45 markers were associated with contribution ranging from 1.1 to 10.23 per cent to variation. newlineThe study yielded first ever partial linkage map of the cultivated groundnut with 59 newlineSSR markers on 13 LGs covering 909.40 cM (32%) and ten QTL for LLS (1.4 to 6.2%), one newlineQTL for rust (4.6 - 4.7%) and six QTL (3.2 - 11.3%) for different yield related traits with the newlinecontribution of favorable alleles from GPBD 4 for resistance and TAG 24 for yield related newlinetraits. The investigation revealed a need for further saturation of genetic map for complete newlinedissection of traits through QTL approach. newline