LINKAGE MAPPING OF 25-KDA GLOBULIN GENES ON HOMOEOLOGOUS GROUP-1 CHROMOSOMES OF BREAD AND DURUM-WHEAT

Acid polyacrylamide-gel electrophoresis (A-PAGE) of ethanol-soluble pr oteins from the endosperm of bread and durum wheats reveals some bands encoded by genes on the homoeologous group-1 chromosomes with higher mobility than the alpha-gliadins. The isolation of these proteins show ed that they were the previously described '25-kDa globulins' encoded by genes at the Glo-A1, Glo-B1, and Glo-D1 loci. The variability found among a collection of 51 bread and 81 durum wheats was very low: two allelic variants at Glo-A1 and no variants at Glo-B1 in each of the tw o species, and two allelic variants at Glo-D1 in bread wheat. Inherita nce studies of '25-kDa globulin' genes on group-1 chromosomes of bread and durum wheat were carried out on the F-2 progeny from four crosses , two in bread wheat and two in durum wheat. The linkage mapping of th e 1A '125-kDa globulin' genes of bread wheat was done based on four pr olamin loci: Glu-A1, Glu-A3, Gli-A1 and Gli-A3. The percentages of rec ombination and the distances found allowed a re-evaluation of the link age map of endosperm protein loci on this chromosome. The Glo-A1 locus was found to be located at the distal end of the short arm of 1A chro mosome, at a distance of 5.23 +/- 1.99 cM from Gli-A1, 6.85 +/- 2.22 c M from Glu-A3, 22.64 +/- 3.62 cM from Gli-A3, and at a recombination p ercentage of 49.30 +/- 4.40 from Glu-A1. A similar distance between Gl i-A1 and Glo-A1 (4.82 +/- 1.75 and 6.66 +/- 2.26 cM) was found in duru m wheat. The distance between Gli-D1 and Glo-D1 on chromosome ID was 2 .86 +/- 1.39 cM.