Plant & Animal Genome V Conference
Town & Country Hotel, San Diego, CA, January 12-16, 1997.
PAG-V: P88 - VARIABILITY OF RESISTANCE TO <i>Colletotrichum lindemuthianum</i> IN THE THREE CENTRES OF DIVERSITY OF COMMON BEAN.
P88
VARIABILITY OF RESISTANCE TO Colletotrichum lindemuthianum IN THE THREE CENTRES OF DIVERSITY OF COMMON BEAN.
SICARD, DELPHINE(1), Yannis Michalakis(2), Michel Dron(3), Claire Neema(3)
1. Institute of Evolution, University of Haifa, 31905 Haifa, Israel
2. Laboratoire d'ecologie, CNRS URA 258, Universite Paris VI, 7 quai Saint Bernard, 75252 cedex 05, France
3. Institut de biotechnologie des plantes, Universite Paris XI, Bat 630, 91405 Orsay, France
The variability of resistance to Colletotrichum lindemuthianum was investigated in the centers of diversity of common bean. Plants and strains of C. lindemuthianum were collected from natural populations of Mexico, Ecuador and Argentina, respectively located in the Meso-American, North-Andean and South-Andean centers of diversity of common bean. Resistance of 17 Mexican, 9 Ecuadorian and 22 Argentinian plants was tested against 10 Mexican, 6 Ecuadorian and 10 Argentinian strains. Among the 48 plant tested, 38 different resistance phenotypes were detected. 11 resistance phenotypes are found in Mexico, 8 in Ecuador and 20 in Argentina. Plant resistance reactions to sympatric and allopatric pathogen strains were determined. All Mexican plants and most of the Ecuadorian and Argentinian plants are resistant to allopatric strains. In contrast, less than 50 % of the plant reactions of each population to sympatric strains are resistance reactions. ANOVA analysis shows a highly significant host-by-parasite interaction effect. These results show polymorphism for resistance both between and within the three centers of diversity. Susceptibility of plants to local strains indicates a local adaptation of the pathogen towards host from the same region. Resistance of plants to allopatric strains reveals the existence of different resistance genes in the three countries. It suggests that the three centres of diversity are differentiated for resistance genes.