Alleles at the GLI loci are reliable genetic markers with great resolution

The use of multiple allelism at the GLI loci encoding the grain storage proteins, gliadins, makes it possible, theoretically, to distinguish between half a billion of common wheat homozygous genotypes differing among them at least at one GLI locus. No one case of the identity of gliadin genotype was observed among unrelated cultivars in our study of about 1000 registered world-wide cultivars (seed-by-seed analysis). Three well-distinguished types of intra-varietal non-uniformity were observed in the material studied: authentic biotypes (morphologically identical lines appearing as a result of segregation of heterozygous genotype produced by breeder), single foreign seeds (admixtures), and different types of mutant seeds carrying mutations at the GLI loci. Another finding made using gliadin alleles for wheat genotype identification is that wheat polymorphism is not proportionally distributed around the world. Groups of cultivars bred in different countries and even in regions of the same country might differ strongly in the frequency of specific alleles at the GLI loci. The possibility of a role of some alleles at the GLI loci in determining dough quality is discussed.