Variation in Fusarium graminearum isolates from Nepal associated with their host of origin

A collection of group II Fusarium graminearum isolates obtained from maize, wheat and rice from different locations in Nepal were identified using a c ombination of morphological and molecular criteria. The variation within th is collection was analysed using RAPD markers, intergenic spacer (IGS) RFLP and PCR polymorphisms. The isolates were divided into two groups, A and B, by RAPD analysis. Isolates in group A yielded four different PCR polymorph ic markers, but all the isolates in group B yielded a single polymorphic ma rker. The IGS RFLP analysis was consistent with division of the isolates in to two groups. Isolates from wheat and rice were more frequently placed in group A, with isolates from maize more evenly distributed between the group s. Results indicate that host preference might be a factor in the division of isolates, although the year of isolation may also have had an influence. No geographical factors or agricultural practices could be identified to a ccount for the observed variation.