Response of QTLs for heading date In rice at different sites from tropical to temperate regions

摘要

A total of 26 QTLs for heading date were obtained from 28 experiments carried out at 10 sites from tropical to temperate regions using 191 recombinant inbred lines (RILs) derived from a cross involving indica (Milyang 23) and japonica (Akihikari) cultivars. These RILs were evaluated in tropical and temperate regions; at IRRI in the 2000 dry season and at nine sites located from Kyushu to Tohoku in Japan from 1995 to 1999, respectively. Because the QTL corresponding to a photoperiod-sensitive gene, Sel, on chromosome 6 was not detected in these analyses, it was estimated that these two parents have the same allele on the locus. In temperate regions, it was found that two QTLs located on chromosomes 7 and 11 had a strong effect on heading date. Although the two QTLs were not detected in the tropical region, four specific QTLs were recognized on chromosomes 2,3,9, and 10. It was hypothesized that the genes relating to vegetative growth played an important role in segregation in the tropical region andthe photoperiod-sensitive and vegetative growth genes had a combined effect in temperate regions because it was assumed that the QTL on chromosome 7 corresponded to a photoperiod-sensitive gene, E1.