| With the development of wheat breeding, a vast of results indicated that narrow genetic basis of wheat resources has become a limiting factor in the process of the wheat yields and quality improvements. So enhancing genetic diversity of wheat resources is the key for lessening biotic and abiotic frangibility. Due to possessing mass of useful genes and rich genetic variations, wild relative of wheat has played an important role in the process of improving the genetic basis of common wheat. So the exploitation and utilization to key genes in wild relative of wheat is significant to broaden the genetic basis of wheat breeding and sustainable wheat production.The objectives of the present studies were to analyze and evaluate genetic diversity of synthetic hexaploid wheats (2n=6x=42, AABBDD) at the levels of the protein and the DNA, which were kindly provided by the International Maize and Wheat Improvement Center (CIMMYT, Mexico) and the Institute of Crop Germplasm Resources (ICGR, CAAS). The results indicated that:1. One hundred thirteen synthetic hexaploid wheats were tested for their resistance to wheat powdery mildew by inoculating with No. 15 physiological race which was prevalent at Beijing region, and were evaluated for resistance to three physiological races CYR31, CYR32 and Shuiyuanl4 of wheat stripe rust in China which have become the dominant and epidemic races at full period of duration. The results indicated that out of 113, 54 accessions displayed resistance to powdery mildew, in which 14 accessions displayed immunity or approximate immunity. Additionally, 48 accessions among 113 were found resistance to stripe rust, in which 11 accessions displayed immunity or approximate immunity from stripe rust.2. A standard acid polyacryamide gel electropheresis (A-PAGE) was used with 96 synthetic hexaploid wheats to evaluate their genetic diversity. As a result, total 65 gliadin bands differing in mobility were detected in these accessions analyzed. All gliadin bands showed different frequencies (from 1.04% to 91.67%) in their gliadin patterns. The highest values of polymorphic information content (PIC) and the Simpson index (SI) obtained at (2.8066, 0.9348) and (2.8778, 0.8475) region, while a (1.4311, 0.7199) region shared the lowest values. Correlative analysis between the gliadin bands indicated there were 56 gliadin blocks composing of 3-5 tightly linked gliadin bands. These gliadin blocks were mainly distributed over + and a regions. The mean genetic distance between accessions was 0.86. The UPGMA dendogram, based on a similarity matrix by a simple matching coefficient algorithm, delineated the above accessions into 4 major clusters and was in accordance with the available pedigree information.3. A collection of 103 accessions of the synthetic hexaploid wheats was characterized for the composition of high molecular weight glutenin subunits (HMW-GS), encoded at loci Glu-1, was revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Large ranges of allelic variations at three complex loci (Glu-Al, Glu-Bl and Glu-Dl) were found. There were five allelic variations among which "Null" allele and subunit 2* were the most frequent at Glu-Al locus. TheGlu-B1 locus showed the largest range of allelic variation and found 12 allelic variations. Among above 12 allelic variations, 14+15, 7+8, and 6+8 were the most frequent. Except for 5 allelic variations (Glu-Dla, Glu-Dlb, Glu-Dlc, Glu-Dld, and Glu-Dlg) found frequently in common wheat. Meanwhile, Glu-Dl locus also coded an unknown novel subunit, which had the molecular weight less than that of subunit 12 which has the lest molecular weight so far found in common wheat significantly. Compared with common wheat, the heterozygosity observed in some accessions at the allelic loci indicated that synthetic hexaploid wheats had the potential genetic differentiations.4. Ninety-five synthetic hexaploid wheats were analyzed using 45 wheat microsatellite markers (among which, 10, 15, and 20 primers sets belong to the A, B, and D genomes,... |
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