Genetic diversity study of Cercospora canescens (Ellis & Martin) isolates, the pathogen of Cercospora leaf spot in legumes

Abstract

Genetic diversity was studied in eleven different isolates of Cercospora canescens (Ellis & Martin), the causative agent of Cercospora leaf spot in legumes. The isolates, which were obtained from different geographical locations, had different morphological and pigment production characteristics. The polymorphism at the molecular level was studied by random amplified polymorphic DNA (RAPD) marker technique and variation in the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA). RAPD profiling clustered all the isolates into three clusters. Considerable genetic diversity was observed in the isolates from the same geographical location. rDNA analysis showed length variation in ITS of two isolates from mungbean, with one 600 bp band common to both. Restriction analysis could differentiate between the common 600 bp bands of the two isolates. The present study indicates that compared to restriction analysis of the ITS region, the RAPD technique is better suited for determining the genetic diversity and differentiation of C. canescens isolates.