PRODUCTION AND GENETIC-CHARACTERIZATION OF NEAR-ISOGENIC LINES IN THEBREAD-WHEAT CULTIVAR ALPE

Two biotypes of the bread-wheat cultivar Alpe were shown to possess co ntrasting alleles at each of the glutenin (Glu-B1, Glu-D1, Glu-B3 and Glu-D3) and gliadin (Gli-B1 and Gli-D1) loci on chromosomes 1B and 1D. Fourteen near-isogenic lines (NILs) were produced by crossing these b iotypes and used to determine the genetic control of both low-molecula r-weight (LMW) glutenin subunits and gliadins by means of one-dimensio nal or two-dimensional electrophoresis. Genes coding for the B, C and D groups of LMW subunits were found to be inherited in clusters tightl y linked with those controlling gliadins. Southern-blot analysis of to tal genomic DNAs hybridized to a gamma-gliadin-specific cDNA clone rev ealed that seven NILs lack both the Gli-D1 and Glu-D3 loci on chromoso me 1D. Segregation data indicated that these ''null'' alleles are norm ally inherited. Comparison of the ''null'' NILs with those possessing allele b at the Glu-D3 locus showed one B subunit, seven C subunits an d two D subunits, as fractionated by two-dimensional A-PAGExSDS-PAGE, to be encoded by this allele. Alleles b and k at Glu-B3 were found to code for two C subunits plus eight and six B subunits respectively, wh ereas alleles b and k at Gli-B1 each controlled the synthesis of two b eta-gliadins, one gamma- and two omega-gliadins. The novel Gli-BS locu s coding for two omega-gliadins was shown to recombine with the Gli-B1 locus on chromosome 1B. The two-dimensional map of glutenin subunits showed alpha-gliadins encoded at the Gli-A2 locus on chromosome 6A. Th e use of Alpe NILs in the study of the individual and combined effects of glutenin subunits on dough properties is discussed.