Ranjan, R. K.Yamleshwar2020-11-172020-11-172020M/PP/264/2018-19https://krishikosh.egranth.ac.in/handle/1/5810155131Wheat (Triticum aestivum L.) belonging to the family Graminae is a major cereal food crop in the world. Globally, wheat cultivated over an area of about 221.6 million hectare with an annual production of 750.4 million tons in 2016-17 (Anonymous 2018). India the second largest wheat producing country in the world after China has the production of about 98.61 million tons with an average productivity of 33.18 q/ha and cultivated over an area of about 29.78 million hectare (ICAR-Indian Institute of Wheat & Barley Research, 2018). The main wheat growing states in India are Uttar Pradesh, Punjab, Madhya Pradesh, Haryana, Rajasthan and Bihar. Bihar rank 6th in wheat production and cultivated over an area of about 2.04 million ha, production 5.74 million tonnes and productivity 28.16 q/ha (ICAR-Indian Institute of Wheat & Barley Research, 2018). Wheat crop is affected by approximately 120 different diseases, among them, 42 diseases are seed borne and 35 diseases are caused by fungi (Hasan et al., 2005). In India, the important seed borne diseases of wheat are rust, smut, bunt, leaf blight & ear cockle disease. Hence, the investigation on “Identification and management of pathogen associated with wheat seeds” has been undertaken to determine the quality and health status of wheat seeds produced by the farmers in Bihar and their management by chemical and botanical oils. I Total 70 seed samples of different variety were collected from the farmers of different villages of Samastipur and Muzaffarpur districts of Bihar state for studies of mycoflora associated with wheat seeds and their management. Collected seed samples were categorized in four categories i.e., Shrivelled, discoloured or black point, damaged and healthy seeds. In Samastipur seed samples, shrivelled, discoloured, damaged and healthy seeds were found 8.53%, 8.16%, 6.57% and 76.72% respectively. While in case of Muzaffarpur seed samples shrivelled, discoloured, damaged and healthy seeds were found 7.68%, 5.54%, 4.88% and 81.90% respectively. Study on germination percentage by standard paper towel method, in Samastipur and Muzaffarpur seed samples average seed germination percentage recorded were 72.87% and 74.47% respectively and seedling vigour were recorded 1923.56 and 2309.60 in Samastipur and Muzaffarpur seed samples respectively. Study on bunt and loose smut disease detection, all seed samples were free from bunt and loose smut disease. Three methods for isolation of seed associated mycoflora i.e., standard blotter paper method, standard agar plate method and standard paper towel method, were used. Five seed associated mycoflora i.e., Aspergillus sp., Alternaria triticina, Bipolaris sorokiniana, Fusarium moniliforme and Penicillium sp. were detected and isolated from Samastipur and Muzaffarpur seed samples. Aspergillus sp. and Alternaria triticina were found dominating fungus in all three methods. In study of different chemicals against isolated pathogens, Propiconazole found most effective against B. sorokininana, followed by Mancozeb and Mancozeb + Carbendazim. In case of Fusarium moniliforme Alternaria triticina and Penicillium sp., Propiconazole has shown highest percent inhibition of growth at lowest concentration. However, in case of Aspergillus sp, Mancozeb + Carbendazim found most effective followed by, Copper oxy chloride. Study on efficacy of different botanicals oils against isolated pathogens, lemongrass oil found most effective against B. sorokiniana. Neem oil found most effective to inhibit the growth of Fusarium moniliforme. Eucalyptus oil found most effective to inhibit the growth of Alternaria triticina at all concentrations. Neem oil found most effective to inhibit the growth of Apergillus sp. and Penicillium sp. at all concentration 100, 200 & 300ppm.EnglishThesis