Identification of New Gliadin Alleles of Mutant, Recombinant, and Introgressive Origin in Bread Wheat Varieties

A special feature of the major gliadin loci in wheat is multiple allelism. Catalogs of gliadin blocks encoded by alleles at the gliadin loci in bread wheat were compiled and are regularly updated. When analyzing gliadin patterns of Ukrainian bread wheat varieties and F2 seeds, the authors identified new alleles at the Gli-A1, Gli-B1, and Gli-A3 loci that had not been previously described in the literature. Gliadin blocks encoded by alleles at the Gli-D1 locus that were described previously but are absent in the latest published catalogues are also presented. Acid polyacrylamide gel electrophoresis of gliadins was performed by the procedure developed by the authors. New alleles were given temporary designations. At the Gli-B1 locus, new alleles of recombinant origin, Gli-B1fg* and Gli-B1eg*, and of mutant origin, Gli-B1ba*, were identified, and alleles of introgressive origin were also detected: Gli-B1xm* (also identified in T. dicoccum accessions), Gli-B1bl* (Gli-B1b with two linked genes, probably from Ae. variabilis, according to the variety Lastivka Odeska pedigree), and Gli-B1wb* (1BL.1RS with a block of ω-secalins as in the variety Amigo). The patterns of Gli-D1 alleles that are not present in the published catalogue of gliadin alleles are also given: Gli-D1ct* from Ae. tauschii and Gli-D1x, apparently of mutant origin, corresponding to the GLD 1D10 block, which was previously identified in some Odessa varieties, in particular Olvia and Prokofievka. At Gli-A1, two new alleles, Gli-A1ag* and Gli-A1ah*, were identified, which were formed via combination with certain alleles at the minor locus Gli-A6. The allele Gli-A3e, which encodes two ω-gliadins, was identified at the minor locus Gli-A3. This allele, which is widespread among spring bread wheat varieties, seems to be extant as it was also identified in T. dicoccum.