Variation in D-genome controlled seed storage proteins in hexaploid and wild species of wheat

Chromosomal location of gliadin components has been obtained for different cultivars of bread wheat (T. aestivum ssp vulgare) and T. aestivum ssp. spelta, through the analysis of aneuploids and intervarietal substitution and addition lines, by two-dimensional electrophoretic techniques. Most of the components, present in the different species, have been assigned to specific chromosomes of the homoeologous groups 1 and 6. Grouping of gliadin components is similar to what has been already reported, with group-1 controlling the slow omega and gamma components, and group-6 controlling athe alpha and beta components. Two-dimensional electrophoretic analysis, carried out on different subspecies (ssp macha, spelta, compactum, vavilovii, sphaerococcum, vulgare) belonging to the hexaploid group of genomic formula AABBDD and on different accessions of Ae. squarrosa showed the existence of large variation in the overall gliadin pattern in different subspecies of T. aestivum and in different accessions of Ae. squarrosa. Comparison of chromosomal location data and two-dimensional glidain maps revealed close homologies between the different hexaploid subspecies. The D-genome electrophoretic pattern of T. aestivum ssp spelta is identical to the one present in many of the bread wheat cultivars analyzed. This pattern is present also in many accessions of the different subspecies of hexaploid wheat. The limited variation in the D-genome controlled storage proteins in hexaploid wheats in comparison to the one shown by Ae. squarrosa supports the hypothesis that a limited number of crosses gave rise to cultivated hexaploid wheats.