Candidate Gene Mapping Pyramiding of Stay Green and Water use Efficiency Qtls and Mapping of Putative Qtls for Root Traits using Ril Populations in Sorghum

Abstract

Recombinant Inbred Populations (RIPs) derived from the crosses IS9830 x E36-1 newline(RIP1) and N13 x E36-1 (RIP2) were used to map localize the drought tolerance-related newlinecandidate genes through SNPs. A total of five QTLs flanked by at least one candidate gene newline(SNP) were found common across both RIPs: qGLA3 (Xtxp38-Xsnp19); qGLA4 (Xiabt227- newlineXsnp56) qDAF2 (Xiumc136-Xsnp28) qPL4 (Xisp229-Xsnp36) and qSY4 (Xsnp36-Xtxp27). newlineThe three stable QTLs for stay-green, qSTG1A:Xtxp34-Xtxp285; qSTG2: Xtxp205- newlineXtxp231; qSTG3:Xtxp298-Xtxp324 and one QTL for water use efficiency, qCID2:Xtxp6- newlineXiabt70 were introgressed from E36-1 the stay-green parent into SPV86, SPV570 and M35-1. newlineThe foreground and limited background screening across BC1F1, BC2F1, and BC3F1 newlinegenerations was done and the BC3F2 progenies with various QTL combinations in newlinehomozygous condition were identified and selfed. The BC3F3 near isogenic lines (NIL) were newlineevaluated in greenhouse: NIL with all four QTLs in M35-1 (75.83 %), SPV86 (78.48 %) and newlineSPV570 (75.57 %) backgrounds showed per cent green leaf area (GLA) retention on par to newlinethe stay-green donor parent (E36-1, 75.20 %) at physiological maturity. newlineThe two RIPs: E36-1 x Basavanapada (RRIP1) and E36-1 x SPV70 (RRIP2) newlinesegregating for high root volume and root length respectively were field evaluated during rabi newline2010-11. Analysis of variance revealed significance difference among the RILs. A total of 113 newline(55/530 EST-SSRs, 40/275 SSRs, 18/138 SNPs) and 104 (50/530 EST-SSRs, 34/270 SSRs, newline20/138 SNPs) polymorphic markers were genotyped to construct a genetic linkage map newlinespanning 1633 cM and 1800.1 cM, and a total of 30 and 28 putative QTLs were mapped for newlineroot and yield related traits in RRIP1 and RRIP2, respectively. The lack of overlap between newlinethe QTLs of component traits of root and yield, suggested that these two parameters are independent newlineand the possibility of combining these two traits, favorably to enhance productivity newlineof sorghum under receding moisture condition. newline