| Abstract: | Main-effect QTL, epistatic effects and their interactions with environment are important genetic components of quantitative traits. In this study, we analyzed the QTL, epistatic effects and QTL by environment interactions (QE) underlying plant height and heading date, using a doubled-haploid (DH) population consisting of 190 lines from the cross between an indica parent Zhenshan 97 and a japonica parent Wuyujing 2, and tested in two-year replicated field trials. A genetic linkage map with 179 SSR (simple sequence repeat) marker loci was constructed. A mixed linear model approach was applied to detect QTL, digenic interactions and QEs for the two traits. In total, 20 main-effect QTLs, 9 digenic interactions involving 18 loci, and 5 QTL by environment interactions were found to be responsible for the two traits. No interactions were detected between the digenic interaction and environment. The amounts of variations explained by QTLs of main effect were 53.9% for plant height and 57.8% for heading date, larger than that explained by epistasis and QEs. However,the epistasis and QE interactions sometimes accounted for a significant part of phenotypic variation and should not be disregarded. |
