Study the effects of some Trichoderma spp. on tomato growth parameters using three inoculation methods

Background and objectives: Different Trichoderma species play role as suitable alternative for chemical fertilizers and successful biological tool in stable agriculture. These microorganisms show rivalry in food and place sources. They establish in the rhizosphere of most agricultural and non-agricultural plants via producing spores. They also could induce resistance in plants. These properties may lead to pathogen reduction as well as plant growth incitation. Favorite effect of Trichoderma species on the plant growth depends on type of species, strains and inoculation methods. Therefore this research has been tried to compare growth effects of four different Trichoderma species using three methods including seed coating, soil application and shoot spraying on tomato growth factors.
Materials and methods: Four Trichoderma spp. including Trichoderma sp (T1), Trichoderm virens (T2), Trichoderma harzianum (T3, T4) and Trichoderma koningi (T5) were evaluated on tomato growth under completely randomized design based on factorial mmethod with four replications in greenhouse conditions. Three methods, consisting of seed coating, soil application and shoot spraying were applied under pot experiments and the performance of all three methods was evaluated according to the isolates. Fungal inoculation suspension was prepared for each method separately. For instance in seed coating method, 3×106 Trichoderma spore on seed surface was estimated. Approximately 107 propagle per gram of soil was calculated for soil application method and in shoot spraying 107 spores per ml was prepared. Statistical analysis was carried out based on averages comparison by LSD method (P=0.05).
Results: Based on obtained results, soil application method showed meaningful promotion on tomato growth traits especially on dry root and foliar weight in comparison to other techniques. Overall, T1, T2 and T5 selected as the best candidates in trial conditions specifically in soil and seed application methods based on their positive effect on tomato growth factors. Isolate T1 increased root and shoot length by 54 and 45.5 percent respectively over controls in soil application treatment. In addition, the means comparisons using LSD method shows no significant difference between T1 and T2 isolates at 5% possibility level. So there is no difference between these isolates as a bio-fertilizer.
Conclusion: The soil application method was suggested as preferred technique in current study. In addition, it seems that application of T1 (Trichoderma sp.) and T2 (T. virens
) isolates in the form of individual or combined formulation which can be used in the field level and could improve tomato growth and yields significantly.