Allelic variance at the vernalization gene locus Vrn-D1 in a group of sister wheat (Triticum aestivum) lines and its effects on development

Three groups of genes, Vrn, Ppd and Eps, control life-cycle duration in wheat (Triticum aestivum L.). The duration of a developmental phase between two stages is important for freezing resistance, heading time, anthesis and ripening date as well as yield component generation. The aim of the current study was to assess the effect of Vrn-D1 on wheat development. The vernalization genes Vrn-A1, -B1, -D1, -B3, photoperiod gene Ppd-1 and candidate genes Mot1 and FtsH4 for Eps in 'G883', 'Pumai 9' and their offspring, a group of sister lines (SLs) derived from an advanced generation, were genotyped using specific molecular markers. All detected loci were the same in the SLs and their parents except the Vrn-D1 locus. Three developmental traits, spike differentiation process, heading date and final leaf number on the main stem, were characterized in three sowing date treatments in the field. When temperatures increased, cultivars/lines carrying the dominant Vrn-D1 gene entered each spike differentiation process faster than those with the recessive vrn-D1 in the same sowing date treatment. Lines carrying Vrn-D1 had smaller final leaf number on the main stem than those with vrn-D1, and the heading dates of the former were earlier than those of the latter, especially in the fourth treatment, sown on 23 February 2012. These data suggest that Vrn-D1 confers a spring habit on wheat and the vrn-D1 confers a cold, hardy winter habit. The Vrn-D1 alleles play very important roles in semi-winter and tender spring wheat cultivars, especially in warm weather in Henan, China. Regulating developmental traits by tracing Vrn-D1 and getting an ideal combination of Vrn alleles to accommodate different wheat zones is a key role for future wheat molecular breeding.