Molecular Characterization of Vernalization Gene Vrn-B1 in Winter Wheat AGS 2000 and NC-Neuse

Selection of the appropriate allelic combinations for genes in the flowering pathway of wheat is important for development of cultivars adapted to a changing climate. Vernalization genes in wheat modulate the plants rate of reproduction and have been shown to affect traits such as frost resistance and yield potential. In winter wheat, time from planting to ear emergence is influenced by variation for vernalization requirement duration. The ability to flower when plants are exposed to short periods of cold weather can be advantageous when winters are mild but increase the risk of later spring freeze damage in some environments. Analysis of a mapping population from the cross between winter wheat cultivars AGS 2000 and NC-Neuse detected a major flowering QTL co-located with the Vrn-B1 locus on chromosome 5B. The molecular characterization of the vrn-B1 genes in winter wheat cultivars AGS 2000 and NC-Neuse is useful for breeding adapted cultivars for different winter wheat growing regions. Comparison of vrn-B1 coding sequences present in AGS 2000 and NC-Neuse detected considerable variation in the C-terminal domain. Variation in key functional domains of the vrn-B1 protein may be responsible for the differential vernalization response between AGS 2000 and NC-Neuse.