Bio-efficacy of Trichoderma formulation against damping-off caused by Pythium spp. and Rhizoctonia solani Kuhn. on tomato (Solanum lycopersicum)
| dc.contributor.advisor | Majumder, Dipali | |
| dc.contributor.author | Biam, Markidahun | |
| dc.date.accessioned | 2023-02-02T05:41:45Z | |
| dc.date.available | 2023-02-02T05:41:45Z | |
| dc.date.issued | 2019-11 | |
| dc.description.abstract | Damping-off is one of the most prevalent and damaging disease of tomato nurseries in Meghalaya, caused by Pythium spp. and Rhizoctonia solani Kuhn. These pathogens can kill both germinating seeds and young seedlings. Management of damping off by integration of biocontrol agents, specially the Trichoderma spp., not only can reduce doses of fungicides but will be a better management strategy against the damping off of pathogens. Considering the fact, present investigation was formulated and aimed on to evaluate bio-efficacy of Trichoderma formulation against Pythium spp. and Rhizoctonia solani kuhn. cause damping off in tomato. Out of 180 soil samples collected from different habitats (crop rhizosphere, compost manure, forest, jhum areas, pig manure, coal mine and lime stone) of 11 districts of Meghalaya, 97 Trichoderma isolates were identified based on their morphology. Dual culture assays of the twenty screened isolates against damping-off pathogens revealed that the 4 Trichoderma isolates viz. TR55, TR66, TR122 and TR136 were found highly effective in inhibiting Pythium spp. with percent inhibition of 89.26, 88.15, 88.89 and 87.78 respectively, whereas only 2 isolates viz. TR55 and TR122 were effective against R. solani with percent inhibition of 87.41 and 86.48, respectively. Isolate TR55 recorded as the best antagonist against both pathogens causing damping off. All 20 screened isolates were positive for ACC deaminase production whereas 17 were positive for chitinase production. Isolate TR 106 and TR 136 were the best in chitinase production with purple colour zone of 9 cm in diameter. Out of 20 screened isolates tested for other functional attributes (determining antagonistic potentials), 16 isolates were found positive for siderophore and ammonia production, whereas 13 isolates were positive for HCN production. Screening for plant growth promotion traits of 20 isolates revealed that all the isolates produced IAA and Phosphorous with values ranging from 0.33 to 4.96 μg/ml and 0.03 to 0.98 μg/ml, respectively. Presence of antibiotic biosynthetic genes in the 20 isolates by using gene specific primers detected that 12 isolates were positive for β-1,6-Glucanase (Tvbgn3), 10 isolates for Trichodiene synthase (tri5), 14 isolates for Serine protease (prb1) and 17 isolates for Endochitinase (ech42). Only 4 Trichoderma isolates showed presence of all the 4 antibiotic biosynthetic genes tested. Observations of the anamorphic characteristics of the Trichoderma isolates showed variation in anamorphic characters viz., size of phialides, phialospore and conidiophores among the isolates. The sequence analysis of the internal transcribed spacer regions 1 and 2 (using universal primer ITS1 and 4) of the rDNA of the 10 potential isolates showed that they belonged to 2 Trichoderma species viz., T. hamatum (TR 55, TR 66, TR 87 and TR 122) and T. harzianum (TR 64, TR 88, TR 106, TR 109 and TR 136) with amplicon at 600bp in all isolates. Dendogram was generated using alignments containing the ITS region revealed formation of two main clusters with closeness ranging from 13 to 96 per cent. The biopriming of tomato seeds with 4 Trichoderma isolates (TR55, TR66, TR122 and TR136) showed considerable increase in germination percentage and vigour index over control, with the highest germination percentage and vigour index recorded in TR55 (75.13 per cent and 47.99 per cent, respectively). Among the treatments (seed, soil and seed plus soil) highest reduction in incidences of pre-emergence and post emergence damping-off was obtained with the isolate, TR55 (seed plus soil treatment). It also exhibited increase in the growth parameters such as root length, plant height, number of leaves, number of flowers, fresh as well as dry fruit weight and yields of tomato; variety Hybri-017 in the treated crops as compared to the untreated control. The rhizosphere colonization of 4 potent isolates of Trichoderma spp. viz., TR55, TR66, TR122 and TR136 showed that their rate of colonization increases up to 45 days after sowing and reduced at 60 days after sowing in all the treatments. Colonization was highest in TR 55 (3.73 × 106) followed by TR 122 (3.63× 106), TR 66 (3.50× 106) and TR 136 (3.37× 106). Native Trichoderma isolates TR55, TR66 and TR122 performed better in terms of functional attributes viz., disease suppression, growth promotion, rhizosphere colonization, self-life in talc formulation, could be further evaluated under different climatic condition of the state for development of effective Trichoderma formulations found effective can be recommended as a component of integrated disease management practice to manage damping off of tomato in the nursery beds in Meghalaya. | en_US |
| dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810193068 | |
| dc.keywords | Damping off of, Trichoderma spp., Pythium spp., Rhizoctonia solani, Phylogeny and Meghalaya, Solanum lycopersicum | en_US |
| dc.language.iso | English | en_US |
| dc.pages | [22], 140p. | en_US |
| dc.publisher | College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam | en_US |
| dc.sub | Plant Pathology | en_US |
| dc.subject | Damping off | en_US |
| dc.subject | Biological control | en_US |
| dc.theme | Academic Research | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Bio-efficacy of Trichoderma formulation against damping-off caused by Pythium spp. and Rhizoctonia solani Kuhn. on tomato (Solanum lycopersicum) | en_US |
| dc.type | Thesis | en_US |