Variation among Colletotrichum gloeosporioides isolates from infected coffee berries at different locations in Vietnam

摘要

Isolates of Colletotrichum gloeosporioides associated with anthracnose disease on coffee berries in Vietnam were characterized by morphological and molecular methods. Random amplified polymorphic DNA (RAPD) and microsatel-lite-primered PCR (MP-PCR) analyses were employed to investigate the genetic variation among 38 and 51 isolates of C. gloeosporioides, respectively. According to both methods, the isolates mainly grouped in accordance with geographical origins. Higher genetic variation (H = 0·312 and 0·335) in the northern population of C. gloeosporioides than in the southern population (H = 0·261 and 0-186), according to the RAPD and MP-PCR markers, respectively, was indicative of a difference between the northern and southern populations. Moderate gene differentiation (Gst = 0·1) between populations from the north and the south was found. However, there was no differentiation between locations within the northern or southern populations, indicating significant gene flow. A four-gamete test indicated a high level of recombination, particularly in the south. The geographic differences may be explained by different histories of coffee cultivation in different parts of Vietnam. The symptoms caused by the Vietnamese isolates on both hypocotyls and green berries were less severe than symptoms caused by the reference CBD (coffee berry disease; Colletotrichum kahawae) isolates originating from Africa.