ANIL KUMAR, PSWATHI, B2018-05-082018-05-082016http://krishikosh.egranth.ac.in/handle/1/5810044910D5289When twenty five isolates of Trichoderma spp. were dual cultured individually with S. rolfsii, incitant of chickpea collar rot, Trichoderma antagonized S. rolfsii in 11 interactions (44%). In 12 interactions (48%), S. rolfsii antagonized Trichoderma. Only two (8%) interactions resulted in static growth. Isolate T14, T15, T17, T22, Tps1, Th4, Th5, Tv2 and Tsugarcane were found to be more antagonistic to S. rolfsii in dual culture when lysis and overgrowth were taken in to consideration. In pot culture, isolate Th4 (64.4%), T22 (60.2%), Tckp (60.2%), T14 (56.0%), T15 (56.0%), Th2 (52.3%), Th3 (52.3%) and Trice (51.4%) gave more than 50% control of chickpea collar rot when applied to soil. Isolate T12 (63.4%), Th4 (60.2%), Tv3 (52.3%), T2 (51.4%) and Trice (51.4%) gave more than 50% disease control when applied as seed treatment. The Trichoderma isolate Th4 (renamed as Th4-w) was found superior with better in vitro antagonistic potential and with better disease control potential in pot culture. Among the eight solid formulations of Trichoderma assessed using soil application and seed treatment methods, talc formulation (51.0% and 65.9%, respectively) and pesta granules (47.7% and 66.4% respectively) gave superior disease control. Among the three liquid formulations tested by soil application and seed treatment methods, mineral oil formulation (50.0% and 54.0%, respectively) gave superior disease control. Among the three additives tested, viz., CMC, casein and culture filtrate, addition of CMC @ 1% was found better with superior disease control over others. When shelf life of Trichoderma was monitored in terms of Trichoderma population, a gradual decline in the shelf life of Trichoderma was noticed when the formulations in different packing material were stored at ambient and refrigerated temperatures. Talc powder formulation stored in paper cover (7.7x108cfu/g) and mineral oil formulation stored in pet jar (16.7x109cfu/ml) showed longest shelf life (ten months) with highest Trichoderma population among all the treatments tested over both the storage temperatures. Different formulations stored at different temperatures and in different packing material were found superior to pathogen inoculated check in terms of increased germination per cent and plant stand per cent. Two mutants were obtained – one tolerant to DAP (Th4-MDAP) alone and another to both DAP and tebuconazle (Th4-MTEB+DAP) using UV irradiation. Field experiments conducted during Rabi seasons of 2012-13, 2013-14 and 2014-15 under natural field conditions revealed chickpea plant mortality due to S. rolfsii, Fusarium oxysporum f. sp. ciceri and Macrophomina phaseolina. Up to 30 days of crop growth period, there was attack of S. rolfsii only, at 45 days after sowing, mortality due to both S. rolfsii and F. o. f. sp. ciceri was noticed, at 60 days of crop period plant mortality was found to be due to S. rolfsii, F. o. f. sp. ciceri and M. phaseolina, and at 75 days, incidence due to F. o. f. sp. ciceri and M. phaseolina were observed but not due to S. rolfsii. At the final stage (90 days) of crop period only attack of M. phaseolina incidence was noticed. Pooled analysis of 2012-13, 2013-14 and 2014-15 (treatments with wild type only) revealed that plant mortality was 60.8% in absolute control. The lowest plant mortality (34.7%) and the highest disease reduction (42.7%) were observed in seed treatment + soil application of Th4-w. Pooled analysis of 2013-14 and 2014-15 (treatments with wild and mutant isolates) revealed 75.6% plant mortality in absolute control. The lowest per cent disease incidence was noticed with seed treatment + soil application of Th4-MDAP (43.7%), seed treatment + soil application of Th4-w (45.1%) and integration of tebuconazole seed treatment with seed treatment + soil application of Th4-MTEB+DAP (45.6%).en-USnullThesis