Abstract
Seed dormancy is an important agronomic trait for rice and other cereal crops because it is associated with pre-harvest sprouting, which reduces seed quality. Seed dormancy is a typical complex trait determined by a series of quantitative trait loci (QTLs). We attempted to isolate QTLs from a variety of chromosome segment substitution lines (CSSLs) derived from crosses between japonica/japonica, japonica/indica, and japonica/wild rice. Previously, we reported five QTLs related to seed dormancy from "Kasalath". Furthermore, we detected QTLs from additional CSSLs, and wild rice introgression lines. Among them, we reported the molecular cloning of a major QTL designated as "Seed Dormancy 4" (Sdr4). In addition, we performed fine-scale mapping of Sdr7, the QTL on "Habataki" chromosome 1L, using more than 4600 F2 plants, thereby delimiting the candidate region to 24.5 kb. The corresponding genomic sequence of "Habataki" contained one specific gene to the "Habataki" genomes, was an ortholog of the Arabidopsis dormancy-related gene.
We present the data from QTL findings, evaluation, fine mapping for isolation, and functional analysis for understanding the rice seed dormancy network.
