| Vernalization requirement is one of the most important characteristics that can contribute to the adaptability to different environments in common wheat (Triticum aestivum L.). Researches on the vernalization gene and its allelic variation can efficiently facilitate the improvement of growth habit in breeding program. In this study, we have done the genetic study on the spring growth habit of Shimai 12, tested its genotype and cloned the regulatory sites in VRN1 gene. The main results are as follows:1. In the F2:3 lines derived from the cross between Shimai 12 and Shijiazhuang 8 (a winter wheat cultivar), the ratio of the spring, segregating, and winter lines was in accordance to 1:2:1 based on chi-test, showing that the spring growth habit of Shimai 12 was determined by single dominant gene, which was identified as Vrn-D1 by gene-specific markers. The Vrn-D1 gene-specific marker was further used to genotype the F2:3 lines, and the results were consistent with phenotyping, verifying the marker assisted selection for Vrn-D1 in breeding programs.2. In this study, the genotype of ten spring wheat accessions and ten facultative accessions is vrn-A1vrn-B1Vrn-D1vrn-B3. By sequencing the regulatory sites in VRN-D1 gene, we found a single nucleotide polymorphism (SNP) in the CArG box of the promoter region, which was associated with the facultative growth habit. Higher expression level of VRN-D1 gene was observed in the unvernalized spring accessions compared with facultative accessions, indicating that the mutation in the CArG box of the promoter region may repress the transcription of VRN-D1 gene. So we speculate that this mutation might be located in a regulatory site in the promoter region for vernalization response, or that mutations in both promoter region and first intron of VRN-D1 gene might interact in the vernalization regulatory system. The molecular marker was developed to facilitate rapid detection of the new allele at VRN-D1 locus in breeding program.
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