Assessment of the individual and combined effects of Rht8 and Ppd-D1a on plant height, time to heading and yield traits in common wheat
Abstract.Grain yield in cereal crops is a complex trait controlled by multiple genes and influenced by developmental processes and environment. Here we report the effects of alleles Rht8 and Ppd-D1a on plant height, time to heading, and grain yield and its component traits. Association analysis and quantitative trait locus mapping using phenotypic data from 15 environments led to the following conclusions. First, both Rht8 and Ppd-D1a reduce plant height. However, Ppd-D1a but not Rht8 causes earlier heading. Second, both Rht8 and Ppd-D1a promote grain yield and affect component traits. Their combined effects are substantially larger than those conferred by either allele alone. Third, promotion of grain yield by Rht8 and Ppd-D1a is through increasing fertile spikelet number. We speculate that Rht8 and Ppd-D1a act independently and additively in control of plant height, grain yield and yield component. Combination of the two alleles is desirable for adjusting plant height and enhancing grain yield and abiotic stress tolerance.