Genetic diversity of storage protein genes in common wheat (Triticum aestivum L.) cultivars from China and its comparison with genetic diversity of cultivars from other countries

Contemporary trends and perspectives of Chinese winter wheat breeding programs were explored using multiple alleles of gliadin (Gli) and glutenin (Glu)-coding loci as genetic markers. To estimate genetic diversity and specific features of Chinese cultivars, the allele frequencies and genetic diversity H in Chinese wheat pool were calculated and compared to those of cultivars from 11 regions of the world. Among all these cultivars the Chinese ones exhibited the highest allelic diversity of the Gli loci while showing relatively low genetic variability for the Glu loci. Most (96%) of the cultivars examined had unique Gli allele compositions, which enabled to differentiate these cultivars with high precision. Cluster analysis of the genetic distances among the wheats from different regions showed that the Chinese cultivars were close to Italian and Russian ones, sharing with them the common Gli alleles. Clustering of modern cultivars and that of cultivars bred 10-15 years ago was essentially the same. All cultivars from all of the countries examined were classified into three groups according to their quality based on their Glu allele compositions. The Chinese cultivars showed a moderate quality score of 7.0, which conforms to the quality evaluation based on SDS sedimentation. This quality proved to be insufficiently high as compared to cultivars from other countries. However, the genetic diversity estimation suggests that Chinese cultivars have a potential for quality improvement.