Molecular markers for the detection of variability of wilt pathogen in groundnut

A survey was conducted in major groundnut growing areas of Tamil Nadu for the occurrence of Fusarium wilt of groundnut and wilt incidence was observed up to 66.00 per cent in the district. In pathogenicity tests, characteristic symptoms of wilt were observed under glass house condition. Of the five isolates tested for their cultural characters, I1 showed a faster growth rate of 1.29 cm/day. The isolates varied in morphological features and all of them produced microconidia, macroconidia and chalamydospores. Using RAPD markers the genetic similarity among the five isolates of F. oxysporum infecting groundnut was studied and the similarity was observed between 27 to 55% indicating high variability among the isolates.