Efficacy of Trichoderma obtained from healthy rice seeds in promoting seedling growth and controlling rice seed rot and false smut diseases under field conditions

In this study, 87 Trichoderma strains were isolated from healthy rice seeds of the cultivar RD59 and subsequently screened for their antagonistic activities against various rice pathogens using dual culture methods. Out of these, 12 strains exhibited strong antagonistic properties and were further selected for a detailed assessment of their fungicidal effects in controlling rice seed rot and false smut diseases under both laboratory and field conditions. Notably, among the evaluated Trichoderma strains, T. harzianum KUFA 0741, applied to RD59 rice seeds, was found to be the most effective in enhancing root length and shoot height, with increases of 9.73 cm and 29.04 cm, respectively. In contrast, T. asperellum KUFA 0733 significantly improved rice germination, achieving a 95% success rate. Furthermore, T. harzianum KUFA 0741 also demonstrated a pronounced biocontrol effect by reducing the incidence of seedling rot by 39.24%, closely followed by T. asperellum KUFA 0733 and T. harzianum KUFA 0740, which reduced the disease incidence by 37.78% and 34.8%, respectively. In terms of managing rice false smut disease, treatment with T. harzianum KUFA 0740 was observed to be highly effective, significantly reducing disease occurrence in both the panicle and seed by 54.24% and 82.23%, respectively. Additionally, it contributed to an increase in rice yield, reaching 1,571 kg per acre, in contrast to the 1, 241 kg per acre yield observed in the control treatment. The antagonistic activities of these Trichoderma strains appear to be linked to their ability to stimulate rice growth and compete for natural resources effectively. They also displayed compatibility with the fungicide hexaconazole. The outcomes of this study indicate that T. harzianum KUFA 0741 and KUFA 0740 have been validated as potent biocontrol agents against rice seedling rot and false smut diseases and can be combined with compatible fungicides, enabling their use in integrated disease management approaches.