IDENTIFICATION OF A POSITIONAL CANDIDATE FOR A PHOTOPERIOD SENSITIVITY GENE, HD1, IN RICE

¹ National Institute of Agrobiological Resources, Tsukuba, Ibaraki 305-8602, Japan

² Institute of the Society for Techno-innovation of Agriculture, Forestry and Fisheries, Tsukuba, Ibaraki 305-0854, Japan

³ Bio-oriented Technology Research Advancement Institution, Omiya, Saitama 331-8537, Japan

Photoperiod-sensitivity is a factor controlling heading date in rice. We have already identified several quantitative trait loci (QTLs) for heading date by using an F₂ population derived from a cross between japonica variety Nipponbare and indica variety Kasalath. One major QTL, Hd1, was found to be involved in photoperiod-sensitivity and is on chromosome 6. To identify the Hd1 gene, we used high-resolution mapping with many DNA markers. Yeast artificial chromosome, cosmid, and P1-derived artificial chromosome clones containing the Hd1 region have been screened by using DNA markers flanking Hd1. Newly developed DNA markers derived from the selected genomic clones could define about 30 kb of the genomic region of Hd1. Genome sequencing of this region identified probable positional candidates for Hd1.