Rs. Balardin et al., VIRULENCE AND MOLECULAR DIVERSITY IN COLLETOTRICHUM-LINDEMUTHIANUM FROM SOUTH, CENTRAL, AND NORTH-AMERICA, Phytopathology, 87(12), 1997, pp. 1184-1191
Isolates of Colletotrichum lindemuthianum (138 total) from Argentina,
Brazil, the Dominican Republic, Honduras, Mexico, and the United State
s were characterized into 41 races based on virulence to 12 differenti
al cultivars of Phaseolus vulgaris. These 41 races were categorized in
to two groups: those found over a wide geographic area and those restr
icted to a single country. Races 7, 65, and 73 were widespread. Race 7
3 was the most common (28%). Race 7 was found once in Argentina and Me
xico but at a higher frequency in the United States. Race 65 was found
repeatedly in Brazil and the United States. Although 39% of the races
were detected repeatedly and three races were widespread, no race was
isolated from both P. vulgaris gene pools. Phenetic analyses showed n
o obvious patterns correlated with virulence clusters. No geographic p
attern was evident. Molecular polymorphism generated by random amplifi
ed polymorphic DNA confirmed the extensive variability in virulence of
C. lindemuthianum. Virulence phenotypes were grouped into 15 clusters
. The two largest clusters contained isolates from all the geographic
regions sampled. Molecular polymorphism was observed among isolates fr
om races 65 and 73 within and among countries, except among Brazilian
isolates of race 65. The genetic diversity of C. lindemuthianum was gr
eatest in Mexico and Honduras. Our data suggest that C. lindemuthianum
may not be highly structured to specific Phaseolus gene pools.