Diversity of Growth Habits and Their Association with VRN Allele of 81 American Wheat Lines

Eighty-one wheat accessions including 50 southern regional performance nursery (SRPN) lines and 31 northern regional performance nursery (NRPN) lines from the United States were tested to evaluate the growth habit by chilling treatments and to estimate the VRN allele variation with 19 pairs of published VRN primers. Two spring wheat accessions and 44 semi-spring wheat accessions were confirmed based on their chilling days' requirement and polymorphism was found at VRN loci. The Vrn-A1 allele had the highest frequency in the RPN accessions and VA1-CAPs markers identified growth habit of RPN lines. No polymorphism was found at the VRN3 loci and some polymorphism at the region of promoter and the first intron of VRN1 was not always consistent to growth habit in the wheat RPN accessions. The existence of variation in VRN alleles suggested that singly using the dominant Vrn allele is possible to extend the diversity of wheat accessions and improve their adaption to different environments in autumn-sowing region. This information will be useful for the cultivars exploitation and wheat breeding program.