In vitro antagonistic potentials of native Trichoderma spp. against stem rot of French bean caused by Sclerotium rolfsii in Manipur

摘要

Ten isolates of three different Trichoderma spp. were isolated from the rhizosphere of French bean from different locations of Manipur. Among these, five were T.viride (Salam, Samurou, Lilong, Khurai and Thangmeiband), four were T.harzianum (Kongba, Basikhong, Khoijuman and Nambol) and one was T.hamatum (Thoubal). Mycelial growth inhibition of Sclerotium rolfsii in dual culture by Trichoderma isolates ranged from 88.00 to 74.67 per cent. Effect of volatile compound produced by Trichoderma spp. against S. rolfsii ranged from 10.22 per cent to 41.98 per cent where the highest inhibition was recorded with isolate ThmFB3 (41.98 per cent) and for non-volatile compound it was 31.77 per cent at 7.5 % v/v concentrations and 70.22 per cent at 15 % v/v by theisolate TvFBl. Ecological adaptability of four potent Trichoderma isolates showed variation in the colonization of sclerotia under three different soil conditions viz., unsterilized, sundried and sterilized soil, where the highest colonization of TvFBl(44.00 per cent) was observed in sterilized soil. The rhizosphere competence of four potent isolates of Trichoderma spp. viz., TvFBl, ThrFB2, ThmFB3 and ThrFB4 showed variation in the levels of colonization under three different soil conditions. It was observed that the rate of colonization by Trichoderma isolates increased upto 45 days after sowing and reduced at 60 days after sowing.