Virulence analysis and oligonucleotide fingerprinting to detect diversity among indian isolates of fusarium oxysporum f. sp. ciceris causing chickpea wilt.

Virulence analysis of 64 isolates of Fusarium oxysporum f. sp. ciceris causing chickpea wilt collected from major chickpea growing states of India on 14 varieties, including 10 international differentials revealed that the isolates from each state were highly variable. Based on the reactions on international differentials, more than one race was found to be prevalent in every state. Majority of the isolates were not matched with the race specific reactions. Therefore, some of the cultivars, namely, GPF 2, DCP 92-3, and KWR 108 should be included as new differentials to obtain clear-cut differential responses. Randomly amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR), and simple sequence repeat (SSR) markers were used to assess the genetic diversity of these isolates. Unweighted paired group method with arithmetic average (UPGMA) cluster analysis was used to divide the isolates into distinct clusters. The clusters generated by RAPD grouped all isolates into three categories at 25% genetic similarity and into two major categories at 30% genetic similarity. ISSR and SSR analyses also grouped all the isolates into two major categories. Majority of the isolates from Punjab and a few from Rajasthan were grouped in one category while the isolates from all other states were grouped in another suggesting the existence of diverse genetic populations of the pathogen at the same location. Some of the RAPD (OPM 6, OPI 9, P 17, OPN 4, OPF 1, P 17, P 21, and SC 1), ISSR (ISSR 7, ISSR 11, and ISSR 12) and SSR (MB 17) markers clearly distinguished area specific isolates.