GENETIC-RELATIONSHIPS AS ASSESSED BY MOLECULAR MARKERS AND CROSS-INFECTION AMONG STRAINS OF COLLETOTRICHUM-GLOEOSPORIOIDES

Morphological characterisation allows isolates of Colletotrichum gloeo sporioides, Colletotrichum musae and Colletotrichum acutatum to be ide ntified only to species level. Pathogenicity tests and random amplifie d polymorphic DNA (RAPD) markers distinguished a mango biotype of C. g loeosporioides from eight other isolates of C gloeosporioides obtained from five different fruit species. Using these procedures, it was als o possible to distinguish C. acutatum and C. musae both from each othe r, and from the C. gloeosporioides isolates. In cross-infectivity stud ies, isolates of C. gloeosporioides displayed a wide host range with t he exception of isolates from mango, which were highly virulent on man go only. Teleomorphic isolates of C gloeosporioides were clustered tog ether by RAPD analysis. This work has demonstrated the existence of a biotype of C. gloeosporioides which shows specialisation to mango.