| Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most important diseases of wheat (Triticum aestivum L. em Thell) in temperate climates, occurring worldwide. Since the late 1970s, powdery mildew has gradually spread in China,owing to the improvement of cultivation measures, the increase of planting density,water and fertilizer. Especially since the wheat cultivars contained the single gene Pm8 were widely grown in China, the variation of the population of Blumeria graminis f. sp. tritici had resulted in the breakdown of resistance to powdery mildew in the most of wheat cultivars. The several times epidemic of wheat powdery mildew had caused serious loss. Modern scientific research indicated that breeding and popularizing resistant varieties are the most economical, environmental and effective way for controlling powdery mildew in wheat. Abstaining from the wide use of single resistant source, digging new resistant sources consistently, utilizing diversified resistant sources, obtaining multi-gene aggregation and multi-gene pyramid are the effective measures for multi-resistance and durable resistance in wheat. Using diversified 'er xian'resistance sources as the donor of resistant genes, a series of wheat new lines had been obtained through scroll add generation back cross pattern to transfer resistant genes and good germplasm, and to obtain multi-gene pyramid and multi-gene aggregation in Shenyang Agricultural University and China Agricultural University, etc. These lines have excellent characters, such as high yield, good quality and resistance to powdery mildew, stem rust and leaf rust, etc, they are excellent parents materials in wheat resistance breeding. Using classical genetic analysis, cytogenetic analysis and molecular marker, the studies on the inheritance of genes resistant to powdery mildew in a series of single gene lines, multi-gene pyramid lines and multi-gene aggregation lines were conducted in this experiment. The objective of the study is to provide genetic information for the innovation of resistant parents materials and for wheat resistance breeding. It possess very important significance in the theory and practice of wheat resistance breeding. By common analysis methods of classical genetics, the susceptible variety Liaochun10 and nine resistant new lines/varieties were used for establishing one set 7×7 and the other 5×5 of hemi-diallel cross combinations. The seedling of parents, F1, F2 and F3 family lines or BF1 from the cross combinations were inoculated with race no. 15 of Blumeria graminis f. sp. tritici, the results showed that the nine new lines respectively contained one independent dominant gene for resistance to powdery mildew. Of the nine new lines, four lines, SM20121, SM203390, SM20125 and SM200332,contained the same gene Pm12, its resistant response pattern is grade 0;. SM20126 contained one gene Pm21; its resistant response pattern is grade 0. SM96 and SM20005 contained the same gene, monosomic analysis indicated that the gene was Pm16, its resistant response pattern is grade 0. OB21 contained one gene WE9(a temporary name), its resistant response pattern is grade 0;, OB151 contained one gene WE1 (a temporary name), its resistant response pattern is grade 0, the gene WE9 was different from the gene WE1; each of the both was different from Pm16. Eight wheat lines obtained by multi-gene pyramid method were crossed with corresponding single gene lines. The seedling of F2 progeny of eighteen cross combinations were inoculated with race no. 15 of Blumeria graminis f. sp. tritici, the results showed that two lines contained two genes for resistance to powdery mildew respectively, SM20088 contained Pm21 and Pm12;SM20134 contained Pm16 and Pm21. Another six wheat lines contained one gene for resistance to powdery mildew respectively, SM20084 contained Pm12, SM20086 and SM20092 contained Pm21, SM20091, SM20140 and SM20144 contained Pm16. The results showed that major genes pyramiding by common breeding method was doable, but the effect needed to be confirmed in further genetic analysis. If the molecular marker of resistant genes are used for major genes pyramiding, it will have high accuracy and efficiency. A set of spelt monosomic lines as female parent were respectively crossed with wheat new variety SM96 and new line SM20005 to determine the chromosomal location of the gene conferring resistance to powdery mildew in both. Seeding of parents, F1 and F2 from monosomic F1 were inoculated with race no. 15 of Blumeria graminis f. sp. tritici. Analysis of obtained data revealed that one major dominant resistant gene originating from wild Emmer (Triticum dicoccoides)in the variety SM96 and the line SM20005 was located on chromosome 4A. F2 progeny from the cross SM96×pm16 single gene line were inoculated with race no. 15 of Blumeria graminis f. sp. tritici, all of 216 individuals were resistant. SM96 and SM20005 contained the same gene, the result showed that the gene in SM96 and SM20005 was Pm16. At present, Pm12, Pm16, Pm21, WE9 and WE1 in above seventeen lines/varieties are effective genes for resistance to powdery mildew in China. These new lines/varieties have excellent agricultural characters, good quality and high resistance to powdery mildew, some lines have resistance to stem rust, leaf rust and yellow rust. They are valuable resistant parents materials in wheat resistance breeding. New variety SM96 had been examined and approved by Crop Variety Committee of Liaoning Province and it had been designated and popularized. Using bulked segregant analysis (BSA), the random amplified polymorphic DNA (RAPD) analysis was conducted in parents and F2 progeny from the cross... |
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