Epistatic Effects and QTL × Environment Interaction Effects of QTLs for Yield and Agronomic Traits in Soybean

Improving seed yield is an important goal of soybean breeding programs.In this investigation,a soybean SSR genetic linkage map constructed by a total of 447 recombinant inbred lines(RILs) derived from a cross between Jindou 23(cultivar,female parent) and ZDD2315(semi-wild,male parent) and the mixed linear model was used to identify the QTLs of yield and other QTLs for major agronomic traits in a two-year experiment.Nine QTLs bearing additive effects for pod position,plant height,node number on main stem,branch number,stem thickness and yield per plot were mapped in the linkage groups J_2,I,and M.The QTLs of yield per plot,stem thickness,plant height,branch number and node number on main stem showed positive additive effects donated by Jindou 23.Seven pairs of epistatic effects QTLs for pod position,plant height and stem thickness were detected,which had an interaction with environments.The results indicated that the epistatic effects and the environmental factors played an important role in yield per plot and agronomic traits in soybean.It will be very important to pay attention to not only QTLs with major effects but also those with epistatic effects in soybean molecular marker-assisted breeding in considering the stability expression and inheritance of the agronomic traits.