Random amplified polymorphic DNA analysis to determine genetic relatedness among rice and weed infecting isolates of Magnaporthe grisea

RAPD analysis was used to characterize the blast fungus populations attacking rice and its associated weeds. Twenty eight M grisea isolates infecting four different hosts viz Oryza sativa, Eleusine coracana, Echinocloa colonum and Digitaria sanguinalis were collected from contiguous rice fields. DNA of each isolate was amplified using seven random primers. The DNA fingerprints generated using 7 primers suggested that all the isolates were genetically distinct. Cluster analysis delineated the isolates into four distinct groups each corresponding to the host specificity of the isolates. Several host specific bands were also observed. These results indicate that isolates were strictly delimited by their host specificity and gene flow among them was restricted.