The effects of Trichoderma spp. isolates from aydin province on seedling root rot disease and plant growth

This study was carried out to determine the plant growth promoting effects and antagonistic activity of native Trichoderma spp. isolated from soil and plant samples of Aydın province on Rhizoctonia spp. and Fusarium spp. that two main fungus causing damping off disease on cotton. Total 106 soil and over 50 weed/cotton plant samples collected from agriculture fields of Aydın province in 2022- 2023 season, in addition to that samples, some plant samples that brought to the ADÜ Plant Protection Department Mycology Labratory for characterization of fungus species are also included to other samples. A total of 102 Trichoderma spp, 6 Rhizoctonia spp. and 7 Fusarium spp. isolate used in the studies. In the dual culture studies, Trichoderma spp. isolates inhibited the mycelial growth of IPS Rh. 7/3A isolate by 17,67-96.22% and in the range of 25.10-100% in the mycelial growth of ÇLRF isolates. In volatile compound studies, Trichoderma spp. isolates inhibited the mycelial growth of IPS Rh. 7/3A by up to 29.50% and ÇLRF by up to 34.53%. It was observed that all 102 Trichoderma spp. tested had hyperparasitic effect on Rhizoctonia solani and F. oxysporum. In pot studies; considering the effects of Trichoderma spp. applied with biopriming method against ÇLRF (F. oxysporum), InTr 1/1 isolate shows the highest effect, when ETr 12/x isolate shows the lowest. Application of KoTr 2/1 and SuTr 10/1 to the soil with soaking method shows the most effective results when ETr 12/x shows the lowest.xxii The Cebir application shows the only effective results against the İPS Rh. 7/3 A (R. solani) isolate, all off the other applications cannot show any effect and no seed emergence observed. When the effects of the Trichoderma spp. applications on plant development were evaluated; the highest shoot length, plant fresh weight and dry weight data were obtained from T-22 application. For shoot lengths it followed by Cebir and ETr 12/x respectively. For plant fresh and dry weights, it was followed by ÇTr 3/1 and Cebir applications. Minimum shoot length and plant fresh weight data recorded in KoDpTr 2/1 application and plant dry weights on KoPTr 5/3. Considering the results obtained; it was seen that native Trichoderma spp. isolated from Aydın province may have potential to take part in the control of seedling root rot and to support plant growth in cotton, but further studies on the subject are needed.