Vegetos

Abstract

Trichoderma a genus under Ascomycotina, has gained immense importance since last few decades due to its biological control ability against several plant pathogens. In addition, the increased growth response induced by Trichoderma species has also been reported for much kind of crops. A total of sixteen Trichoderma strains were selected to evaluate their antagonistic behavior and plant growth promotion. PCR amplification of internal transcribed spacer regions was used to confirm the identities of Trichoderma isolates used. The in vitro tests against plant pathogens like Phytophthora meadii, P. heveae, P. citrophthora, P. capsici and P. palmivora in dual cultures showed all the Trichoderma isolates growing fast and inhibiting the growth of the pathogens by third day. Maximum growth inhibition of test pathogens was observed by antagonists CPCRI-TD-8 (72.7%) followed by CPCRI-TD-3 (71.7%) after 4 days of inoculation. The cellulase activity was also assayed by analyzing the glucose released in carboxymethyl cellulose solution with spectrophotometry. Highest cellulase activity (31.11 mg glucose liberated/mg protein/30minutes) was recorded by CPCRI-TD-8 which showed a high degree of antagonism to all tested pathogens each by more than 65%. This illustrated that the cellulolytic enzyme and metabolic products may have participated in growth suppression of test pathogens. Growth promoting activity of Trichoderma isolates on green gram seeds was tested under glasshouse conditions and seed germination percentage, root and shoot length, fresh weight, dry weight and vigour index were measured. All the tested Trichoderma isolates showed significant positive effects on vigour index in comparison with the control. Results from this study explored the plant growth promoting activity of Trichoderma sp. and suggests its use as a potential multifunctional bio-fertilizer.