QTL mapping for relative water content trait at reproductive stage drought stress in rice

Abstract

Drought is the main constraint for rice production in rainfed ecologies. Low relative water content (RWC) at reproductive stage is the most important limiting factor for the reduction of yield and its parameters. Identifying QTLs linked to RWC at reproductive stage can provide more opportunity to the researchers in maker-assisted breeding approach. For QTL associated to RWC in rice, two contrasting parents CR 143-2-2 and Krishnahamsa for drought tolerance were utilized for the development of recombinant inbred lines (RILs). Significant variation for RWC was observed among the RILs and parental lines in both the years of study. Bulked segregant analysis was utilized for genotyping of the mapping population. Two hundred and one SSR markers were selected and tested for parental polymorphic analysis from which 77 polymorphic markers were used for genotyping the RILs. Inclusive composite interval mapping detected, qRWC9.1 with LOD value of 4.27 and phenotypic variation (PVE%) of 60.87 within the marker interval of RM316-RM257 on chromosome 9. Consistent effect of this RWC QTL for drought tolerance traits was detected in both the years with the same marker interval. Hence, this QTL may be useful for marker-assisted improvement at reproductive stage drought tolerance in rice.