Types, frequencies and value of intra-varietal genotypic non-uniformity in common wheat cultivars: Authentic biotypes and foreign seeds

Abstract

Seed-by-seed electrophoretic analysis of the seed storage-protein gliadin was used to identify two major types of intra-varietal non-uniformity in grain samples of 756 registered Triticum aestivum cultivars: authentic biotypes(genotypes arising from the original cross performed by the breeder) and foreign seeds (admixed alien genotypesor products of accidental cross-pollination). Authentic biotypes of a cultivar, distinct in alleles at one or more of eight Gli loci (Gli-1,Gli-2,Gli-A3, Gli-B3), occurred in more than 30% of the cultivars studied. Four biotypes ofthe cultivar Saratovskaya-29 (distinct in alleles at the Gli-A1 and Gli-A2 loci) differed significantly in 1000-kernelmass and dough quality. The relative frequency of biotypes changed with time when the cultivar grew in the region where it was bred and, more strongly, in alien regions. There is thus potential value in characterizing multiple biotypes to facilitate the adaptation of a cultivar to given eco-climatic environments. Changes in the frequencies of biotypes alter the grain quality of a cultivar as a whole. Ignorance of possible wheat intra-varietalnon-uniformity (biotypes and foreign genotypes) in a grain material may confuse the interpretation of experimental results infield trails and grain-quality assessments.