Effect of QTLs controlling grain yield under drought stress in the genetic background of ADT45 rice variety

Abstract

Drought is a major production constraint in rain-fed upland and rainfed lowland ecosystems of rice cultivation. A set of two backcross inbred lines (BILs) harboring mega effect QTLs controlling grain yield under stress were developed in the genetic background of ADT 45 through marker assisted selection (MAS) and evaluated for drought tolerance at reproductive stage under rain out shelter. Background selection of BILs showed highest recovery (90%) of recipient genome in the BIL harboring three major QTLs from Apo a tolerant donor. Significant differences were observed among the BILs and parents for grain yield and its contributing traits under both severe moisture stress and well irrigated conditions when compared to ADT 45. The BIL harboring three major QTLs, DTY (2.2+3.1+8.1) [QTLs for yield under stress on chromosome 2,3 and 8] performed better and showed increased values for grain yield, plot yield, spikelet fertility and harvest index thanthe BIL harboring 2 major QTLs DTY (3.1+8.1), which shows pyramiding of more number of QTLs may enhance the grain yield under stress. Both the BILs harboring two and three major QTLs recorded lesser Drought Susceptible Index under severe moisture stress.