Cultural and genetic variability in Macrophomina phaseolina (Tassi.) Goid. and incidence of mulberry root rot

摘要

Five isolates of Macrophomina phaseolina (Tassi.) Goid. were collected from different mulberry growing districts of Tamil Nadu. Among the five isolates, Coimbatore isolate took five days to cover the entire plate. The same isolate also produced a maximum number of sclerotia on solid and liquid medium when compared to other isolates. These isolates were also analysed through RAPD markers for genetic diversity. A similarity matrix and Jacard's similarity coefficient between isolates indicated that these five isolates showed 66-80% similarity coefficient. The five isolates were separated into two clusters, namely A and B. Again cluster A is divided into two clusters, namely A1 and A2. The cluster A1 contains isolates of Erode and Dindigul. These two exhibit 72.5% similarity coefficient. The cluster A2 represents isolate Coimbatore and Salem isolate which exhibited a similarity coefficient of 80%. Cluster B contains Dharmapuri isolate which differed from other isolates of Erode, Dindigul, Coimbatore and Salem.