Increased drought tolerance and wider adaptability of qDTY (12.1) conferred by its interaction with qDTY (2.3) and qDTY (3.2)

摘要

The genetic basis of high grain yield under reproductive-stage drought was studied using an F3-derived population generated from the cross of upland rice (Oryza sativa L.) cultivars Vandana and Way Rarem. Contributed by the susceptible parent Way Rarem, locus qDTY_12.1 was hypothesized to have interaction with loci from the Vandana genome to enhance the grain yield of tolerant line Vandana under drought. A test of the digenic interaction of qDTY_12.1 showed that two loci, qDTY_2.3 on chromosome 2 and qDTY_3.2 on chromosome 3, significantly increased the yield and harvest index of qDTY_12.1-positive lines under severe upland and lowland drought conditions. qDTY_2.3 and qDTY_3.2, in interaction with qDTY_12.1, reduced days to flowering and plant height of qDTY_12.1-positive lines under stress and non-stress conditions in upland. BC2F3-derived backcross inbred lines (BILs) were used to validate these results and identify new quantitative trait loci. Lines with qDTY_2.3 and qDTY_12.1 showed increased yield over Way Rarem under severe and moderate stress conditions, in upland. IR84996-50-4-B-4, a selection from one of the BILs, yielded more than the popular drought-tolerant cultivars Apo, UPLRi7, and IR74371-54-1-1 under severe stress conditions. Introgressed segments from Vandana also improved yield under non-stress conditions. The results indicate that digenic interactions can explain the genetic control of complex quantitative traits such as grain yield under drought, and a few interacting loci with large effects on grain yield or yield-related traits may enhance drought response across a wide range of genetic backgrounds and environments when introgressed together.Digital Object Identifier http://dx.doi.org/10.1007/s11032-012-9760-5