Allele Composition And Genetic Diversity Of Shandong Province Common Wheat Germplasm Based On Storage Protein

In recent years, genetic erosion, or the reduction of the genetic base ofthe common wheat germplasm caused by frequent use of the same or similarparental genotypes for breeding activities, is becoming a serious problem. Itrestricts the genetic potential of wheat, complicates wheat improvement andcould lead to problems. Thus, it is important to evalute the genetic diversityof present cultivars in order to sound genetic basis and change breedingstrategy.In the present study, gliadin allelic composition at Gli-1(Gli-A1, Gli-B1 and Gli-D1) and Gli-2(Gli-A2,Gli-B2 and Gli-D2)loci and glutenallelic compositon at Glu-1(Glu-A1,Glu-B1 and Glu-D1)loci in 37samples of common wheat cultivars grown in Shandong province wereidentified using acid polyacrylamide gel electrophoresis (A-PAGE) andsodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).Genetic variation at the nine encoding loci was calculated and compared. Thegliadin bands, gamma-gliadins 40 and 43.5, whose presence correlates withbread-making quality, were purified and partially characterized and the highlevel of genetic polymorphism in Shandong wheat resources was revealed.The main results are summarized as follows:1. Allelic frequencies of gliadin at Gli-1 and Gli-2 lociThe gliadin allelic compositions at Gli-1 (Gli-A1, Gli-B1 and Gli-D1)and Gli-2 (Gli-A2, Gli-B2 and Gli-D2) loci of 37 common wheat materialswere analyzed by A-PAGE. High allelic variation was found. A total of 58alleles were observed at the six loci. Twelve were identified at Gli-A1 locus,eleven at Gli-B1, eight at each of Gli-D1 and Gli-B2, nine at Gli-A2 and tenat Gli-D2.The most frequent alleles in wheat grown in Shandong were: Gli-A1a (48.6 %), Gli-B1l (35.1%), Gli-D1k (35.1%), Gli-A2b (35.1%), Gli-B2g(35.1%) and Gli-D2a (29.7%) . According to whether Gli-B1l locus existedor not, thirteen 1BL/1RS translocation lines (35.1%) were detected amongtested cultivars (lines). It is suggested that 1BL/1RS translocation linesproportionally exist in Shandong cultivated wheat and play an important rolein wheat improvement.2. Allelic frequencies of gluten at Glu-1 A total of 11 alleles at Glu-1 loci were observed by the method of SDS-PAGE. Three at each of Glu-A1 and Glu-D1, five at Glu-B1. The mostfrequent alleles in wheat cultivars in Shandong province were Glu-A1a (62.2%), Glu-B1b (43.2%) and Glu-D1a (70.2%), which encoding the subunit (1)at Glu-A1, subunit (7+8) at Glu-B1, subunit (2+12) at Glu-D1. The mostsubunits composition pattern were (1, 7+8, 2+12), which were encoded byGlu-A1a, Glu-B1b and Glu-D1a, as represented by 27%. Secondly were (N,7+9, 2+12), encoded by Glu-A1c, Glu-B1c and Glu-D1a, as represented by10.8%.3. Genetic diversity at Gli-1, Gli-2 and Glu-1 loci in Shandong wheatcultivars The genetic diversity was calculated from data for six Gli and three Gluloci in 37 cultivars grown in Shandong. The wheat germplasm appear to bemore extensive and polymorphism. The genetic variation indexes at Gli-1and Gli-2 loci was high varied from 0.7297~0.8269, with the mean of 0.7930.The highest genetic variation index was found at Gli-D2, while the lowestwas found at Gli-A1. The genetic variation indexes at Glu-1 varied from0.4324~0.6618, with the mean of 0.5532. The highest genetic variation indexwas found at Glu-B1, while the lowest was found at Glu-D1. The geneticvariation indexes at Glu loci were much lower than that of Gli loci. Itsuggested that the genetic diversity at Gli loci is higher than that of Glu-1 lociin Shandong wheat cultivars.4. Partially quality prediction based on gliadin and gluten composition The composition of HMW (High-Molecular-Weight) gluten subunit wasinvestigated in the wheat cultivars carrying good-quality gliadin alleles, suchas Gli-B1b and Gli-A2b. The results showed that there were 5+10 glutensubunit associated with good bread-making quality in Yannong 15, Yanyou...