| The powdery mildew in wheat, caused by Erysiphe graminisf. sp. tritici, was one of the main diseases of wheat (Trtticum aestivum L. em Thell.). Using resistant cultivars is one of the most economical, effective and environmentally sound safe measure to control mis disease. Molecular markers tightly linked to resistance genes not only facilitated the identification and map of resistance genes, but also could be used for markers-assisted selection (MAS) of resistant lines in breeding program. Then MAS greatly enhances the aggregation efficiency of genes and accelerated the breeding progress. It was the main intention to make use of the molecular marker techniques such as RAPD, SCAR, STS and SSR etc. to develop the molecular markers mat tightly linked to the resistant genes of the powdery mildew in wheat It will be very helpful to realize the aggregation of multi-genes by MAS to resist the powdery mildew in wheat, to construct the high density map and to isolate the resistant gene by map-based clone.Basing on the common analysis method of RAPD, consulting the reaction system and the amplifying program of our lab, designing grads for the all kinds of ingredient in the course of amplifying, and selecting the most suitable concentration, at the same time, utterly considering the denaturalizarjon time and annealing temperature, I found a reasonable and efficient analysis way that fitted to analyze the genome of wheat. The RAPD analysis for the genome of wheat was carried through with the optimized reaction system and amplifying program. As a result, most random primers could amplify 4-10 clear bands. It is rough estimated that the averagely examined loci per primer was 9-10 locus, which was more than the record (4-7 locus) reported by most references and the examined efficiency was improved evidently. Meanwhile, according to the similar method, I also found out the reasonable reaction system and amplifying program of STS and SCAR markers and carried through the effective amplifying for the experiment materials.The study chose the susceptible materials (chancellor and yumai13) and the resistant materials (Ulka/8*Cc, Yuma/8*Cc, Timgalen, Chiyacao and Hongyoumai) to construct five sets of F2 populations, which were used to resistance identification and genetic analysis. After inoculated the mixed races of the powdery mildew in wheat from zhengzhou city, the plant reactions to the disease was screened. The ratio of resistant and susceptible plants in F2 generation fitted the expected 3 to 1 (the segregation ratio of Chacellor*Ulka/8*Cc was 41:93, X2=2.239; Chacellor*Yuma/8*Cc was 48:129, X2=0.318; Yumai13*Timgalen was 16: 56, X2=0.117; Yumai13*Chiyacao was 34:123, X2=0.766; Chancellor*Hongyotmai was 13: 51, X2=0.521). These F2 segregation populations ensured the accuracy and credibility of linkage between RAPD, SCAR, SSR, STS marker and resistant genes.Based on the conservative sequences of resistant genes, a total of 181 10-mer random primers had intently been chose to make RAPD analysis for the near-isogenic lines (NILs) of Pm2 and Pm4a, the resistant parent of Pm6 and Pm24, and the landrace cultivars Hongyoumai contained unknownPm genes in the contrast of the susceptible parent Chancellor and Yumai13. Through the primary screening, 9 primers could detect the polymorphic segments between Chancellor and Ulka/8*Cc, 10 primers between Chancellor and Yuma/8*Cc, 38primers between Yumai13 and Timgalen and 22 primers between Chancellor and Hongyoumai.The study still validated the random primers that could amplify polymorphic segments in Pm6 and Pm24 gene with partial F2 population, and found two RAPD markers (S139615 and S138443) linked to Pm6 gene and two RAPD markers (S141556 and S153706) linked to Pm24 gene. Then the four segments were recovered, cloned and sequenced. According to their sequence, four pairs of especial primers was designed and synthesized, and the four RAPD markers were successfully converted into four SCAR markers. The two SCAR markers SC-S139615 and SC-S138443 were analyzed and linked to...
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