Discovery Of Novel Allelic Variations At PPD And VRN Locus In Common Wheat

The PPD and VRN genes directely determined the flowering time of wheat and are related to the adaptability to the environment and quality.Discoverying the novel allelic variations of PPD and VRN genes can not only enrich the germplasm resource of wheat but also provide useful parental materials and genetic information for breeding program.Based on the previous results of experiments,we used the materials containing the novel allele,cloned and characterized the sequence,designed the molecular markers,revealed the effects of novel alleles.The main results are as follows:1.A novel dominant allele PPD-B1a.3 from Chinese landrace cultivar GLH was cloned and characterized.The novel allele contained a 4256 bp insertion in the promoter region compared with the known PPD-B1b.1 allele.A pair of primers were designed to identify the novel allele PPD-B1a.3 with 526 bp.The green house experiment?20²4?,10h/d?was used to reveal the effect of novel allele.The effect of this novel allele on heading time is stronger than PPD-B1b.1 allele.We compared the light responsive element of novel allele PPD-B1a.3with known allele PPD-B1b.1 in promoter region revealing that the types and numbers of different light responsive elements is in the rising tendency.Therefore,the large insertion lead to the changes of the promoter composition which turn it into the light insensitive type.2.We successfully comfirmed the former results of the Vrn-B1d sequence and validated the genome specificity of the designed primers.238 F₂ plants derived from a cross between winter cultivar Jing 411 and Hongchunmai were used for evaluation of heading time in the greenhouse under non-vernalizing and long day conditions?20²4?,16h/d?showing that cultivars containing Vrn-B1d allele headed significantly earlier than those with recessive vrn-B1 allele,but later than those with the dominant allele Vrn-D1b.3.A novel dominant allele VRN-B3 from Chinese landrace cultivar HST was cloned and characterized.The novel allele contained a 160 bp insertion in the promoter region compared with the known recessive allele vrn-B3.