RELATIONSHIP BETWEEN THE D-GENOME OF HEXAPLOID WHEATS (AABBDD) AND AE-SQUARROSA AS DEDUCED BY SEED STORAGE PROTEINS AND MOLECULAR MARKER ANALYSES

The electrophoretical analyses of seed storage protein components from the gliadin and glutenin fractions in T aestivum ssp. vulgare, compactum, sphaerococcum, macha, vavilovii, and spelta have revealed limited variation at the tightly linked coding loci Gli-D1/Glu-D3, and Glu-D1, located respectively on the short and long arm of chromosome 1D, and at the Gli-D2 locus, positioned on the short arm of chromosome 6D. Much higher variation was observed, for the same protein components, in the wild diploid Ae. squarrosa, the D genome donor of the aestivum group. Genetic variation in the same wheat subspecies and in Ae. squarrosa has also been evaluated by Southern hybridization of genomic DNAs, which were digested with several restriction enzymes, and hybridized with cloned sequences of genes coding for seed storage proteins. The much higher degree of variation observed for the seed storage protein genes of Ae. squarrosa, in comparison with the variation exhibited by the proteins encoded by the D genome chromosomes of hexaploid wheats, supports the hypothesis that a limited number of crosses gave rise to hexaploid wheats of the aestivum group.