Effect of Culture Filtrates of Fusarium udum Isolates on Germination, Root Length and Wilt Incidence of Pigeonpea Seedlings

The effect of culture filtrates was tested against germination, root length and wilting of pigeonpea seedlings against susceptible cultivar LRG-30 at different concentrations viz., 25ppm, 50ppm, 75ppm, 100ppm and undiluted concentrations of all the 26 isolates of Fusarium udum. Results depicted that germination and root length were reduced and seedling wilt was increased as the concentration of culture filtrates increased and vice-versa. Lowest seed germination and highest disease incidence were recorded with culture filtrate of Fu 24 and that of least was recorded with culture filtrate of isolate Fu 1. Though considerable variation was found among the isolates, most of them were found at par with each other within the same concentration. Across the isolates root length varied from 9.1 cm (Fu 8) in undiluted concentrations to 25.6 cm (Fu 7) in 25ppm. Wilt incidence due to different culture filtrate concentrations on susceptible pigeonpea seedlings was found variable and ranged from 13.3 per cent (25ppm) against isolate Fu 4 to 100 per cent (undiluted culture filtrate) by isolates Fu 15 and Fu 24. This variability in seedling wilt, seed germination and root length may be due to combined effect of variable concentration of Fusaric acid and other enzymes.