Mapping QTLs with additive effects and additive × additive epistatic interactions for harvest index in wheat (Triticum aestivum L.)

To map quantitative trait loci (QTL) for harvest index, ۱۴۸ recombinant inbred lines and their parents, Yecora Rojo and an Iranian landrace line (No. ۴۹), were evaluated under normal and terminal water deficit stress conditions in the research stations of Mahabad University and Miyandoab Agricultural Research Center, Iran, during ۲۰۱۴ and ۲۰۱۵. The experiment was carried out as design alpha lattice design with two replications. A linkage map of ۵۱ retrotransposon and ۱۷۷ microsatellite markers was used in this investigation. Quantitative trait loci (QTL) for additive effects and additive × additive interactions were determined by QTL Network ۲.۰ software using CIM and mixed-linear methods. QTL analysis revealed that under normal condition, six QTLs (R۲A= ۰.۰۴ to ۱۲.۰%), two QTL × environment (E) interactions (R۲AE= ۶.۲۸%), five additive × additive epistatic effects (R۲AA= ۰.۷ to ۸.۶۸%) and ۱۲ additive × additive × E (R۲AAE= ۳.۷۶ to ۱۱.۴%) were significant. Under water deficit stress conditions, two QTLs (R۲A= ۵.۰ to ۷.۰%), two additive × additive interactions (R۲AA= ۳.۷۲ to ۵.۴۸%) and seven additive × additive × E interactions (R۲AAE= ۸.۰۴ to ۹.۵۸) were identified. Among the eight QTLs identified, three QTLs were located on chromosome ۲D, suggesting the importance of this chromosome in controlling harvest index, which may be used for marker assisted selection in breeding programs.

Keywords:

Epistasis , Harvest Index , Microsatellite marker , QTL , Retrotransposon , Wheat