A total of six sequence mutations were detected between Gamenya and Chinese Spring. Four of the mutations had single-base substitutions, one mutation had an insertion/deletion, and one mutation had different numbers of single-base repeats, 17 'G' in Chinese Spring and 10 'G' in Gamenya. We designed a primer pair (5'-TAGGCAGCTTGTTCCTCTGC-3' and 5'-TCAAAGTCCATTGACTACCATCC -3') flanking the latest mutation and conducted PCR with the primers in 14 common wheat cultivars including Chinese Spring and Gamenya. Four cultivate showed the Gamenya genotype and 10 cultivars had the Chinese Spring genotype (Fig.1). Since this marker also gave a polymorphism between Gamenya and Sumai #3, we applied the DNA marker to a mapping analysis with the DH population derived from a cross between Sumai #3 and Gamenya. With the Xbarc series of SSR markers (Song et al. 2000; Shi et al. 2003) and an RFLP marker (Mingeot and Jacquemin 1999) as anchor markers, TaHd1-1 was mapped to the chromosome 6AL and it co-segregated with Xbarc 107 (Fig. 2). This result confirmed the result of the aneuploid analysis by Neonate et al. (2003).

Although Nemoto et al. (2003) found that transgenic rice with TaHd1-1 complemented the deficiency of Hd1. we did not detect an association between TaHd1-1 and heading date in the DH population derived from Sumai #3 and Gamenya that was grown under natural conditions in Tsukuha, Ibaraki, Japan, in 2002 and 2003 (unpublished data). The DNA marker for TaHd1-1 developed in the present study, as well as the flanking SSR and RFLP markers, will be useful for studies on the genetic effect of TaHd1-1 under different photoperiod conditions and in different wheat genetic backgrounds.

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