Distribution and Selective Effects of Vrn-A1, Vrn-B1, and Vrn-D1 Genes in Derivative Varieties from Four Cornerstone Breeding Parents of Wheat in China

Vernalization, the process of a long exposure to low temperature to induce flowering in plants, is essential for plants to adapt to cold winters. The presence of vernalization genes Vrn-A1, -B1, and -D1 in four cornerstone breeding parents of wheat in China (Funo, Mentana, Yanda 1817, and Bima 4) and 322 derivative varieties (mostly winter wheat) from these parents were determined using PCR based molecular method. The frequencies of the VRN-1 genes in these derivative varieties were in order of Vrn-D1(67.1%)> Vrn-B1(19.6%)> Vrn-A1(5.3%), which are similar as the former conclusion that Vrn-D1 is associated with the latest heading time, Vrn-A1 the earliest, and Vrn-B1 intermediate values. The frequencies of Vrn-A1 and Vrn-B1 loci in the derivative varieties from winter wheat zones were higher than that from spring winter zones. Based on the wheat breeding history in China and the fact of non-random distribution of Vrn-A1 and Vrn-B1 in the derivative varieties from the four parents, there could be a strong selective effect on VRN-1 genes in different regions where the derivative varieties were cultivated.