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Mapping of Hd-6-2 for Heading Date Using Two Secondary Segregation Populations in Rice
- Hua, Zhang, Xu, Liu, Yongyi, Yang, Ning, Xuan, Fangyin, Yao
- Rice science 2018 v.25 no.3 pp. 161-168
- chromosomes, cultivation area, genetic distance, heterozygosity, parents, phenotype, promoter regions, recessive genes, rice, sequence alignment, substitution lines
- Heading date is one of the most important traits for rice adaption to different cultivation areas and crop seasons. In this study, two single segment substitution lines (SSSLs), W31-41-61-3-11-3-6-7 (W31-SSSL) and W32-59-80-2-11-1-10 (W32-SSSL) with substituted intervals derived from the donor parents IR66897B (W31) and IR66167-27-5-1-6 (W32), respectively, with Huajingxian 74 (HTX74) were found to comprise a gene for extremely late-heading date, and the gene was tentatively designated as Hd-6-2. Two secondary F2 segregating populations were developed by crossing the two heterozygous SSSLs with HJX74 to map Hd-6-2 gene. According to phenotype analysis of the two mapping populations, the late heading date trait was controlled by a major recessive gene. In the segregation population derived from W31-SSSL, Hd-6-2 was mapped on chromosome 6 between PSM677 and RM204 with the genetic distances of 1.3 and 2.7 cM, respectively. In the population of W32-SSSL, the gene for heading date was mapped to the similar region as Hd-6-2 and co-segregated with PSM672. The sequence alignment of Hd3a in the coding domains and promoter regions of HJX74 and W31-SSSL are completely consistent, whereas there was a great difference between W32-SSSL and HJX74, suggesting that Hd3a could hardly be the main cause of the heading date variation in W31-SSSL, but it was probably the main reason for the change of heading stage in W32-SSSL.