Genetic characteristic of resistance to powdery mildew and Septoria glume blotch in wheat
Abstract
Powdery mildew caused by Erysiphe graminis DC f. sp. tritici Em. Marchal is an important disease of wheat (Triticum aestivum L. em Thell). Genetic analysis of resistance to powdery mildew indicated that resistance of Zhengzhou 871124 is conferred by a single dominant gene. Further analysis suggested that the resistance gene in Zhengzhou 871124 is Pm1. RAPD-PCR analysis was carried out by using bulked segregant analysis of closely related lines developed from a segregating F$\sb5$ family. The F$\sb5$ family was derived from a cross between the susceptible cultivar Clark and the resistant line Zhengzhou 871124. After carrying out RAPD-PCR analysis with 1300 arbitrary 10-mer primers, two RAPD markers, UBC320$\sb{420}$ and UBC638$\sb{550}$, were found to be cosegregating with powdery mildew resistance. No recombinants were observed between either of the two RAPD markers and the gene for resistance to powdery mildew after analysis of 244 F$\sb2$ plants. The third RAPD marker, OPF12$\sb{650}$, was identified by using denaturing gradient gel electrophoresis (DGGE), and was determined to be 5.4 $\pm$ 1.9 cM from the resistance gene. Both UBC320$\sb{420}$ and UBC638$\sb{550}$ were observed only in the wheat powdery mildew differential line carrying gene Pm1 and they were detected in Pm1-containing lines of different genetic backgrounds, suggesting linkage between the markers and the Pm1 resistance gene. The RAPD marker UBC638$\sb{550}$ was converted to STS. The method of deriving closely related lines from inbred families that are segregating for a trait of interest should find wide application in the identification of DNA markers linked to important plant genes. The availability of RAPD markers that are tightly linked to target genes may facilitate selection and enable gene pyramiding for powdery mildew resistance in wheat breeding programs. Glume blotch, caused by Stagonospora nodorum (Berk.), is another important disease of wheat. The results indicated that both arms of chromosome 3A and the long arms of chromosomes 4A and 3B, were involved in the flag leaf resistance to S. nodorum. Both arms of chromosome 4A, the short arm of chromosome 3A, and the long arm of chromosome 3B, were found to confer spike resistance to S. nodorum.
Degree
Ph.D.
Advisors
Ohm, Purdue University.
Subject Area
Agronomy|Genetics|Plant pathology
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