Pathogenic and Molecular Variability of Aspergillus niger Isolates Causing Collar Rot Disease in Groundnut

Pathogenic variability studies of 26 isolates of collar rot pathogen (Aspergillus niger) of groundnut collected from different districts of Telangana and Andhra Pradesh states were conducted under greenhouse conditions by using two groundnut cultivars TMV-2 and JL-24. The mean seedling mortality ranged from 29.7 per cent (MBNRAn-1 (Palkapally)) to 94.4 per cent (ATPAn-1 (Jogannapet)). All the isolates of A. niger showed differential reaction with regard to seedling mortality on JL-24 and TMV-2 cultivars. Similarly genetic relatedness among eight virulent isolates (two isolates from each district) of A. niger from groundnut was assessed by using RAPD analysis. The similarity index values among the A. niger isolates varied from 0.571 (between WGL An-2 and CHT An-3) to 0.229 (between MBNR An-3 and WGL An-2).