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Title: LINKAGE VERSUS ALLELISM OF TWO MAJOR RUST RESISTANCE GENES IN PHASEOLUS VULGARIS

Author
item Stavely, J
item GRAFTON, K - ND STATE UNIV., FARGO, ND
item KELLY, J - MI STATE UNIV, E. LANSING

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/22/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A dominant rust resistance gene, Ur-3, is present in certain bean cultivars that produces distinct minute, hypersensitive, necrotic spots after infection with 43 of 87 races of Uromyces appendiculatus. P. vulgaris plant introductions 181996 and 190078 contain a dominant resistance gene or complex locus, previously tentatively designated Ur-3 2, that produces a minute uredinium, resistant reaction to many races and permits a susceptible reaction to only one, recently identified race that is controlled by Ur-3. Segregation in F2 and F3 plants from crosses between plants homozygous for Ur-3, but lacking Ur-3 2, and plants homozygous for Ur-3 2, but lacking Ur-3, produced 3:1 ratios for each gene, but many fewer plants with both dominant genes then would be expected if they were independently inherited. In the F 2 and F 3 populations only very few plants lacked both. A few F 3 plants were homozygous for both. Thus Ur-3 and Ur-3 2 appear to be closely linked in repulsion.