© 2007, INSInet Publication Identification and Prediction of the Flour Quality of Bread Wheat by Gliadin Electrophoresis

Abstract: Gliadin proteins were used to identify and characterize 30 wheat varieties. SDS-PAGE of gliadins revealed a total of 30 bands ranged from 74.5 to 6.5 kDa, where the number of total bands varied between varieties. The region of omega-gliadin had a wide range for a number of bands. Among gliadin protein bands, nine bands were monomorphic and 21 bands were polymorphic, which were used to characterize the wheat varieties. The similarity index and dendrogram demonstrated the genetic relationships among wheat varieties using the gliadin protein bands resulted from SDS-PAGE analysis. In the studied Egyptian wheat varieties, the gliadin band of ã-45 related to high gluten quality, while the ù-38 band related to moderate gluten quality. However, it was found that ã-42 band related to low gluten quality. The concentration of each gliadin protein subgroup was varied among the wheat varieties and some of gliadin subgroups were related partially to gluten quality in some varieties. The obtained results indicate that gliadin proteins analysis is useful as biochemical genetic markers for characterizing the wheat varieties and detecting flour quality

Effect of long-term heat stress on grain yield, pollen grain viability and germinability in bread wheat (Triticum aestivum L.) under field conditions

Frequent episodes of heat threaten sustainable agriculture in Egypt. This study is an urgent call to select tolerant genotypes of heat and discover the predicted screening phenotypic parameters. Here, twenty spring wheat genotypes were exposed to heat stress under field conditions for screening heat tolerance. Stress environments were simulated by delaying the sowing date by 53 and 58 days than the normal environments for two successive seasons. Stressed plants received the highest peak of heat during the reproductive growth stage. Eight phenotypic parameters were measured to evaluate genotype tolerance. Mean performance, reduction percentage/trait, and heat susceptibility index parameters were calculated. Additionally, the pollen grain viability during spike emergence and the germinability of producing grains were investigated. Results demonstrated: (1) Highly significant differences (P < 0.01) between genotypes, treatments and genotypes by treatments in grain yield and other traits in both studied seasons, (2) significant reduction in all studied traits compared to the non-stress environment, (3) the overall yield reduction, based on grain yield/m2, was 40.17, 41.19 % in the first and second seasons, respectively, and the most tolerant genotypes were Masr2, Sids1, Giza 171 and Line 9, (4) limited impact of heat has detected on pollen grains viability and germinability, and (5) grain yield as a selection criterion for heat stress remains the most reliable yardstick