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Bean rust pathogen variability measured by virulence and the random amplified polymorphic DNA (RAPD) technique
Abstract
The analysis of virulence patterns on Phaseolus vulgaris of 145 Uromyces appendiculatus cultures originating from distinct geographic regions revealed no patterns that correlated virulence with geographic origin. The cluster analysis of the cultures based on virulence similarity, identified 75% of the cultures as moderately virulent, 12% as virulent and 12% as moderately avirulent. Two cultures, USA Races 38 and 39, were classified in a single and separate cluster. Both these races were isolated from snap bean but had the lowest disease scores on the bean differentials. Regression analysis of the reaction of the 19 bean differentials to two sets of 145 and 373 rust cultures supported previous findings that common resistance genes or gene complexes exist in a number of differentials. These results also emphasized the need to modify the composition of the present set of differentials used to study virulence variability in bean rust. Preliminary results of rust virulence surveys in Morocco identified the differentials Mexico 309 and 51051 as sources of rust resistance for the improvement of local varieties. The study of genetic similarity between 48 U. appendiculatus cultures using the random amplified polymorphic DNA (RAPD) technique revealed variation in banding patterns between cultures. Unique bands were detected in profiles of Races 38 and 39 with all primers tested and in profiles of the rust cultures H87ZA3A10-2, H87EAP7B-19 and H87HP19, isolated from snap bean cv. Provider, with the primer OPF-04. The presence of these unique bands reflects the genetic differences between the snap bean races and the other U. appendiculatus cultures as suggested at a high level of confidence by the parsimony analysis. The cluster analysis did not show a correlation between RAPD profiles and geographic origin but showed one possible relationship between RAPD markers and virulence patterns. Both markers isolated Races 38 and 39 into a single and separate cluster. The absence of a correlation between geographic origin and virulence or RAPD markers suggests genetic exchange between and within rust populations from the Americas and Africa.
Subject Area
Plant pathology|Genetics|Molecular biology
Recommended Citation
Meskine, Mohammed, "Bean rust pathogen variability measured by virulence and the random amplified polymorphic DNA (RAPD) technique" (1994). ETD collection for University of Nebraska-Lincoln. AAI9500607.
https://digitalcommons.unl.edu/dissertations/AAI9500607