Sequence-Related Amplified Polymorphism-PCR Analysis for Genetic Diversity in Rhizoctonia solani Populations Infecting Pulse Crops in Different Agro-Ecological Regions of India

Abstract

A B S T R A C T Rhizoctonia solani is a destructive fungal pathogen infecting wide range of crop plants including pulses causing wet root rot or web blight disease. The present study was aimed to determine the genetic diversity of R. solani populations using Sequence-Related Amplified Polymorphism (SRAP) markers. The SRAP markers were used for genetic diversity analysis of 89 isolates of R. solani belonging to 7 Anastomosis Groups (AGs) isolated from different pulse crops representing 21 states from 16 agro-ecological regions of India. Out of 30 SRAP primer combinations evaluated, 16 combinations provided amplification with 100% polymorphism and the primer combinations Me1/Em1and Me1/Em4 provided the highest number of bands (14). The isolates of R. solani showed high level of genetic variability and grouped into 7 major clusters at 35% genetic similarity by using unweighted pair group method with an arithmetic average analysis. Bootstrap analysis grouped the isolates into five major clusters at 28% genetic similarity and about 95% isolates shared common sub-grouping patterns in both the analysis. The majority of the isolates representing various AGs were grouped together into different sub-clusters. The molecular clusters did not correspond to agro-ecological regions and crops of the origin of the isolates because of the diversity in the hosts and adopt ability of the pathogen under different environmental conditions prevalent in various parts of the country. First time an attempt was made in the present study to determine the genetic variability of the R. solani populations isolated from different pulse crops representing various AGs using SRAP markers.