Allelic variation and differential expression of VRN‐A1 in durum wheat genotypes varying in the vernalization response

The purpose of this research was to study the effect of vernalization on flowering time in thirty accessions of Triticum turgidum spp. durum. To this end, screening of allelic variation at VRN-1 loci was carried out using PCR-based markers and DNA sequencing, and gene expression analysis was performed in two and four developmental stages, with and without cold treatment. In non-vernalized plants, average days to flowering ranged from 34 to 99 days and only one accession was observed to remain at the vegetative stage. Three accessions were found to accelerate flowering after cold treatment. At VRN-A1 locus, three alleles previously characterized, Vrn-A1b, Vrn-A1c and vrn-A1, were detected. No polymorphisms at VRN-B1 locus were observed. The differences in vernalization response among the genotypes studied could be explained by allelic variation and VRN-A1 transcript levels. Variability in flowering time and sensitivity to vernalization in a collection of durum wheat, both potentially useful to the development of new varieties, were observed. This information is key to directing breeding cultivars for adaptation.