Upadhyay, J. P.Ahsan, Md. Shahzaman2018-02-052018-02-052016http://krishikosh.egranth.ac.in/handle/1/5810040406The soil samples collected from KVK, Birauli and Dr. RPCAU (RAU), Pusa were analysed for texture, pH and organic carbon content. The texture of soil samples collected from RAU, Pusa and KVK Birauli was sandy loam except the mango orchard of KVK, Birauli which was silt loam. The pH of soils of litchi orchards was slightly acidic while it was neutral in soils of mango orchard. The fungal population in soils of mango and litchi orchrds was studied on Peptone dextrose rose bengal agar medium using dilution plate technique. The population of total fungi in different soil samples of mango and litchi orchrd of Pusa and Birauli ranged from 9.00 X103 cfu/g of soil to 9.60 X103 cfu/g of soil. The population of total fungi in different soil samples did not differ significantly. In soil samples of KVK, Birauli, population of Trichodrma (ranged from 2.50-2.60 cfu/g soil) while in the the soil samples of RAU, Pusa it ranged from 3.3- 3.6 cfu/g soil. The result indicated that population of Trichodrma is available in all soil samples with varying population. Five isolates of Trichoderma were observed in isolation of total fungi from soils of mango and litchi orchards of RAU, Pusa and KVK, Birauli. The isolates were purified on PDA and identified as Tricoderma harzianum based on cultural and morphological characters like colony character, mycelium, conidiophores, phialides and phialspores. The characteristic symptoms of collar rot of chickpea caused by Sclerotium rolfsii observed are - sudden drooping and chlorosis of leaves and petioles, external rotting of collar region of stem and root (at seedling stage) and white fluffy growth of Sclerotium rolfsii at the collar region upon which mustard grain like brown sclerotia were formed. Five isolates of T. harzianum such as Th1, Th2, Th3, Th4 and Th5 were compared for their capability of antagonism towards S.rolfsii in dual culture. T. harzianum isolate 4 proved best in dual culture and parasitized the colony of S. rolfsii earliest. T.hazianum 4 also showed maximum inhibition in formation of sclerotia of S. rolfsii (73.30%) in dual culture. Viability studies on mycelium and sclerotia of S. rolfsii in dual culture with T. harzianum in antagonized plate revealed lysis of both mycelium and sclerotia. Five Fungicides- Propiconazole, Hexaconazole, Bavistin, Topsin M and Vitavax at 100, 250 and 500 ppm concentrations were evaluated for their efficacy against S. rolfsii in vitro. Propiconazole, Hexaconazole and Vitavax completely inhibited the growth of S. rolfsii in vitro while Bavistin and Topsin M showed 79.52 and 71.78% growth inhibition respectively at 500 ppm. Investigation on host resistance against collar rot of chickpea viz., DKG 964, BG 372, BG 3051, PUSA 256, BAUG 15, C 235, GAG 1107, JG 315, JG 62 and BG 3043 revealed that out of 10 cultivars tested in pot soil artificially infested with S.rolfsii, none showed resistant reaction against the disease. Seed treatment with fungicides significantly reduced the sedling mortality of chickpea when compared with control. Seed treatment with Vitavax @ 2 g/kg of seed proved that best and showed 73.32% disease control followed by Propiconazole @ 2 g/kg. Soil application of maize grain based culture of T. harzianum at 5, 10, 15 and 20 g per pot showed significant reduction in seedling mortality. Maximum control of collar rot (53.33%) was recorded in treatment where T. harzianum was applied @ 20 g per pot. The integration of soil application of maize grain based culture of T. harzianum (10 g per pot) with Vitavax seed treatment @ 2 g/kg seed proved best combination and gave maximum disease control over check (79.95%). Integration of seed treatment with T. harzianum and Vitavax showed 59.90% disease control which was higher than Vitavax 0.2% seed treatment alone but did not differ significantly with each other.ennullThesis