Allelic Variation in Vernalization Loci and Its Relationship with Field-Based Growth Habit of Bread Wheat (Triticum aestivum L.) Promising Lines

Bread wheat is one of the most important food crops that is grown in different climatic conditions across the world. One of the important factors for this wide adaptability is the role of vernalization genes in different wheat genotypes. Therefore, identification of allelic variations of these genes provides an opportunity to determine growth habit, prediction of cold tolerance and adaptability of bread wheat genotypes to different climatic conditions. In this study, growth habit of 40 promising bread wheat genotypes was evaluated in the field and glasshouse during two and one cropping seasons, respectively. Allelic variation in VRN-1 and VRN-3 loci was also determined using nine locus-specific primer pairs. In VRN-A1 locus; Vrn-A1a, Vrn-A1b, Vrn-A1c and vrn-A1 alleles had frequencies of 7.5%, 7.5%, 10% and 67.5%, respectively. In this locus, three genotypes did not produce any band. In VRN-B1 locus; dominant and recessive alleles had frequencies of 52.5% and 47.5%, respectively, and in VRN-D1 locus; dominant and recessive alleles had frequencies of 60%, 40%, respectively. In VRN-3 locus; the majority of genotypes (97.5%) had recessive allele (vrn-B3). Results of this study indicated that different alleles of VRN-A1 locus had more influence on field growth habit as compared to VRN-B1 and VRN-D1 loci, and different combinations of these alleles resulted in range of various field growth habits from true spring to true winter. The results of this study can be used in the national bread wheat breeding programs for pyramiding favorite alleles of vernalization genes to improve adaptability of bread wheat genotypes for different target agro-climatic zones of Iran.