CHANGES IN WHEAT SEED STORAGE PROTEIN FINGERPRINT DUE TO SOIL MINERAL-CONTENT

Wheat seed storage protein fingerprint is used to determine the gluten protein pattern in studies aimed at improving flour quality. Wild whe at with high seed protein content is used extensively in wheat breedin g programs. Although the wild wheat growth and protein content may be influenced by environmental conditions, the gluten-protein pattern is generally considered as indicative of a genotype, without the superimp osition of environmental influences. The effects of soil type, habitat , and deficiencies of N, P, K and S on seed storage protein compositio n were examined in nine accessions of wild wheat (Triticum turgidum va r. dicoccoides) and three varieties (two T. aestivum and one T. durum) . Soil from ten natural habitats of the wild wheat that had not previo usly received any fertilizers or manures was sampled and used to grow wheat in a greenhouse. Seed storage protein composition was characteri zed by SDS-PAGE. Although deficiencies in soil nutrient caused variati ons in the seed storage proteins, the genotype was the main factor det ermining the seed storage protein composition. Seed storage protein co mposition of genotypes varied when grown under different mineral nutri ent conditions. Only one genotype was stable showing almost identical protein patterns under all growing conditions studied without any qual itative change in fingerprint pattern. In the other genotypes, as well as the cultivars, the seed storage protein was affected at least to s ome extent by the soil. The 'soil effect' is summarized in terms of th ree main quantitative changes in the seeds: 1 - the relative amounts o f the high-molecular-weight proteins; 2 - the relative amounts of prot eins in the range of 45 and 65 kD; 3 - the percentage distribution of the HMW glutenin and other groups of seed storage proteins. The soils induced also qualitative differences in the composition of seed storag e proteins, mostly in those of 45-65 kD. These differences were observ ed whenever a deficiency of S, N, P, K or Mg was identified. Therefore , in breeding programs that use seed storage protein fingerprints of w ild wheat germplasms should be exercise caution when the germplasms se lected from wild habitats.