A new quantitative trait locus (QTL),
Hd9, controlling rice heading date was detected in a BC
4F
2 backcross population derived from a cross between a
japonica rice variety, Nipponbare, as the recurrent parent, and an
indica variety, Kasalath, as the donor parent.
Hd9 was precisely mapped on the short arm of chromosome 3 as a single Mendelian factor; progeny testing of BC
4F
3 lines derived from BC
4F
2 plants revealed that it co-segregated with the RFLP marker S12021. In addition, a nearly isogenic line (NIL) of the target QTL, NIL(
Hd9), in which a small chromosomal segment of Kasalath including
Hd9 was substituted into the genetic background of Nipponbare, was selected from the progeny based on marker-assisted selection. Days to heading of NIL(
Hd9) increased under long-day and natural field conditions at Tsukuba, but remained almost the same under short-day conditions as that of the isogenic control, Nipponbare. Analysis of F
2 populations derived from crosses between NIL(
Hd9) and either NIL(
Hd1) or NIL(
Hd2) revealed that the phenotypic gene effect of
Hd9 was additive to that of
Hd1 and
Hd2. This result suggests that no epistatic interaction was involved. Based on these results, we discussed the biological function of
Hd9.
抄録全体を表示