Construction of genetic linkage map and QTL analysis for foliar disease resistance nutritional quality and productivity traits in groundnut Arachis hypogaea L

Abstract

Groundnut (Arachis hypogaea L.) is an important oilseed and food crop of the world. newlineBreeding for disease resistance, improved nutritional quality and productivity are the major newlinechallenges in groundnut breeding. Conventional breeding has had limited success for newlineimprovement of these traits. Advent of molecular markers provides useful way to map and tag newlinefor the desired traits in any crop. An attempt has been made to construct the linkage map for newlineidentification of QTLs for foliar disease resistance, nutritional quality and productivity traits newlineusing 53 polymorphic SSR markers in 146RILs (TG-26xGPBD-4). newlineGenetic variability components revealed higher magnitude of variation for all the newlinetraits. Heritability was high for disease and nutritional quality but lower for productivity traits. newlineAll the traits showed normal distribution except rust which had bimodal distribution indicating newlinethe complex and simple nature of inheritance, respectively. Correlation between LLS and rust, newlineprotein and oil, oleic and linoleic was negative whereas, number of pods correlated positively newlinewith pod yield. newlineA partial linkage map with the total distance of 657.9cM (8LGs) and an average newlineintermarker distance of 14.62cM was constructed using 45 markers (23% genome). Single newlinemarker and QTL analysis identified a total of 23 markers and 5QTLs for disease resistance, newline35 markers and 17QTLs for nutritional quality and 34 markers and 13QTLs for productivity newlinetraits. Among them QTL near XIP103 on LG3 for rust (24.10 48.90%), oil content (7.90 newline9.10%), number of pods (4.41 6.10%), pod yield (6.60 11.20%), a QTL near TC3A12 on LG8 newlinefor plant height (12.60 17.50%) and a QTL near TC1B02 for test weight (8.20 14.0%) newlineshowed consistent results across the seasons with substantial contribution and the favorable newlineallele was contributed by GPBD-4 parent. From the study one major QTL (XIP103) has been newlineidentified which could be employed in MAS for identification of rust resistant genotypes.