Allelic variations of puroindoline genes affecting grain hardness in Iranian bread Wheat cultivars

Grain hardness has an important role for discriminating marketability and commercial classes in world trade in hexaploid wheat (Triticum aestivum L.). Hardness (Ha) locus controlled by a single locus comprised of the Puroindoline a, Puroindoline b and Grain Softness Protein-1 (Gsp-1) genes. A large deletion in the puroindoline a (Pina) gene or single nucleotide polymorphisms (SNPs) in the puroindoline b (Pinb) gene results in hard grain texture. When both puroindolines are wild-type, grain texture is soft. When either of the puroindoline alleles is absent or alter by mutation, then the result is hard texture. In this study, some new Iranian commercial cultivars were investigated for their kernel hardness and puroindoline alleles using STS-PCR and SNPs genotyping. The results indicated that approximately half of the cultivars had Pina-D1b or Pinb-D1b allele and genotype the other half of the cultivars not identified and to identify other cultivars should be used to their detector primers. In this study, Gonbad, Sirvan, Oroom, Bahar, Aflak and Moqan3 cultivars had Pina-D1b allele and zaree cultivar showed Pinb-D1b allele. Pina-D1b alleles showed the most frequency among our cultivars. This study showed that cultivars with hardness genotype have accordance with Inframatic machine (NIR) results. Correlation coefficient (r = 0.74) between hardness index (HI%) and water absorption (WA%) by using Inframatic machine (NIR) was significant (α<0.0001). Our knowledge about the genetic basis of kernel hardness could provide useful information in breeding programs of bread wheat.