Study on Epistatic and Q×E Effects of QTLs for Indica Head Milled Ratio

QTL mapping for head milled ratio(HR) trait of rice in different seasons and years were analyzed by using a mixed model approaches and composite interval mapping methods(CIM) in MJ recombination inbred lines(RIL).Epistatic effects and QTL×enviroment interaction(Q×E) were also investigated.It was shown that two additive QTLs for HR were located in RM154-RM485 and RM248-RM234 intervals on the chromosome 2 and 7,with contribution ratio(H2) respective of 1.92% and 7.85%,and the total H2 of 9.78%.Furthermore,three pairs of epistatic effect areas were detected.The epistatic effect between RM335-RM518 on chromosome 4 and RM340-RM439 on chromosome 6 was 3.66%,and the rest were 0.In Q×E effects analysis,the H2 of two additive QTLs interacting with enviroment were 5.70% and 8.74% respectively,and the total H2 was14.44%.The total H2 of the epistatic QTLs interacting with enviroment was 2.94%.In summary,Q×E effects played a control role in the heredity of HR trait in MJ RILs.