Variability in the isolates of Macrophomina phaseolina

Fourteen isolates of Macrophomina phaseolina (Tassi) Goid. collected from different groundnut growing regions in India were studied for their virulence and genetic diversity using PCR-RAPD markers. All the isolates showed variation in their pathogenicity. A total of 85 amplicon levels were obtained with 7 primers with an average of 12.1 band per primer, were available for analysis, of which 83 were polymorphic (97.74%). It was possible to discriminate all the isolates with any of the 7 primers employed. The UPGMA clustering of data indicated that the isolates shared varied levels of genetic similarity within a range of 0.069 to 0.65 similarity coefficient index. The average genetic similarity coefficient observed was 0.248±. Isolates Bikaner, Churu, Delhi, Hisar which were clustered in one group happened to be more virulent also, thus reflecting correlation of similarity with pathogenicity to some extent but there was practically no direct correlation between the virulence and RAPD genetic markers of all the isolates.