Genetic variation among isolates of Bipolaris maydis using RAPD_PCR

Abstract

Maydis Leaf Blight prevalent in many parts of India is a major threat to maize cultivation when grown in warm and humid climates. The pathogen responsible is Bipolaris maydis (Y. Nisik. & C. Miyake) Shoemaker. Ten isolates of the fungus were selected from different geographical regions in India for the present study. Preliminary primer screening was carried out using 32 primers from OPM, OPB and OPN series (Operon Technologies, Inc., USA) for molecular variation analysis. Out of 32 primers used for amplification of DNA of all isolates of B. maydis, two resulted in either sub-optimal or non-distinct amplification products. The similarity coefficients subjected to UPGMA-SAHN to produce a dendrogram, resulted in two major clusters, which separated Bm-6 from rest of the isolates, which were grouped in two major cluster, one having Bm-3 and Bm-2 and the second one having the rest of the isolates in two sub clusters. The first sub cluster included Bm-4 and Bm-7 while Bm-1, Bm-5 and Bm-9 were grouped in second sub cluster. Isolates Bm-8 and Bm-10 were different from rest of the isolates in the second sub cluster thus remained one grouped. In present investigations though significant correlation between the genetic similarity and geographical origins could not be established.