title: Genetic dissection of a genomic region for a quantitative trait locus, Hd3, into two loci, Hd3a and Hd3b, controlling heading date in rice.
abstract: The rice photoperiod sensitivity gene Hd3 was originally detected as a heading date-related quantitative trait locus localized on chromosome 6 of rice. High-resolution linkage mapping of Hd3 was performed using a large segregating population derived from advanced backcross progeny between a japonica variety, Nipponbare, and an indica variety, Kasalath. To determine the genotype of Hd3, we employed progeny testing under natural field and short-day conditions. As a result, two tightly linked loci, Hd3a and Hd3b, were identified in the Hd3 region. Nearly-isogenic lines for Hd3a and Hd3b were selected from progeny using marker-assisted selection. The inheritance mode of both Hd3a and Hd3b was found to be additive. Analysis of daylength response in nearly-isogenic lines of Hd3a and Hd3b showed that the Kasalath allele at Hd3a promotes heading under short-day conditions while that at Hd3b causes late heading under long-day and natural field conditions.
authors.affiliation: Institute of the Society for Techno-innovation of Agriculture, Forestry and Fisheries, Tsukuba, Ibaraki 305-0854, Japan.
authors.forename: L.
authors.initials: L
authors.lastname: Monna
authors.forename: X.
authors.initials: X
authors.lastname: Lin
authors.forename: S.
authors.initials: S
authors.lastname: Kojima
authors.forename: T.
authors.initials: T
authors.lastname: Sasaki
authors.forename: M.
authors.initials: M
authors.lastname: Yano