Identification of strains of Fusarium udum through host differential studies

Abstract

Pathogenic behaviour of all the forty one isolates of F. udum on six pigeonpea host differentials indicated the existence of at least four strains in F. udum. Most of the F. udum isolates showed virulence reaction on cultivars TTB-7 and Bahar, whereas none of the isolates showed virulence on ICP 8863 and ICP 9174. Based on wilt reaction on six pigeonpea host differential lines, forty one F. udum isolates collected from major pigeonpea growing areas were categorised into four strains. Strain I included nine isolates viz., APFu-7, APFu-9, KFu-10, MSFu-1, MSFu-2, MSFu-3, MSFu-4, TNFu-2, and TNFu-5, and they were grouped as least virulant. Strain II comprised of fifteen isolates viz., APFu-1, APFu-4, APFu-5, APFu-6, APFu-8, APFu-10, APFu-11, KFU-6, KFU-7, KFU-8, KFU-9, KFU-12, TNFu-1, TNFu-3 and TNFu-4 and were grouped as moderately virulant. Strain III consisted of twelve isolates viz., APFu-2, APFu-3, BFu-1, KFU-4, KFU-5, KFU-11, KFU-13, KFU-15, KFU-16, MPFu-1, NDFu-1 and WBFu-1 and they were grouped as more virulant. Strain IV comprised of five isolates viz., KFU-1, KFU-2, KFU-3, KFU-14 and UPFu-1 and they were grouped as most virulent.