SREE LAKSHMI, BLAKSHMI PRAVALLIKA, PALUSANI2019-06-262019-06-262018http://krishikosh.egranth.ac.in/handle/1/5810110052D5593The present investigation was carried out in the laboratory of Plant Pathology, Regional Agricultural Research Station, Lam and Department of Seed Science and Technology, Advanced Post Graduate Centre, Lam, Guntur, Andhra Pradesh during 2017-2018 to estimate seed borne mycoflora of sesame, their impact on seed quality parameters and management of seed borne fungi in sesame. A total of 28 including 16 farmers‟ saved seed samples of sesame were collected from different farmers‟ and research stations from various sesame growing areas in Andhra Pradesh and Telangana states. The seed samples were analysed for seed borne mycoflora by standard blotter method, deep freezing blotter method, 2, 4-D blotter method, water agar method, agar plate method with PDA and paper towel method. A total of seven fungal species belonging to six genera viz., Alternaria sesami, Curvularia sp., Fusarium sp., Helminthosporium sp., Rhizopus sp., Aspergillus flavus and Aspergillus niger were found to be associated with the seed of sesame indicating their seed borne nature. Among these fungi, the mean incidence of Alternaria sesami was highest (31.44%), while that of Helminthosporium sp. was found to be the lowest (4.82%) in all the detection methods. Among the six methods, standard blotter method was found to be superior by recording maximum incidence of mycoflora (31.48%) from all the test samples, while water agar method (9.50%) was found to be least effective for the detection of seed borne fungi. Samples collected from farmers‟ were highly infected with different mycoflora when compared to samples collected from research stations in all the six detection methods. The inhibitory effect of major seed borne fungus, Alternaria sesami was observed on seed germination, seedling length and seedling vigour index of sesame seed samples collected from different sources and locations. Significant differences in seed germination, seedling length and seedling vigour index were observed among the uninoculated as well as inoculated sesame seed samples. The results indicated that xv Alternaria sesami caused 15.13% to 49.68%, 12.77% to 46.14% and 28.28% to 72.87% per cent reduction in seed germination, seedling length and vigour index, respectively of inoculated seed over uninoculated seeds. The per cent reduction was highest in the seed samples of YLM-17 collected from farmers‟ of Prakasam district. A total of eleven fungicides, six botanicals and six bio-control agents were evaluated against Alternaria sesami under in vitro conditions using poisoned food technique and dual culture technique, respectively. Among them, fungicides viz., Combination product of carbendazim 12% + mancozeb 63% @ 0.2% and hexaconazole @ 0.2%; bio-control agents Trichoderma viride (isolate-2) and Pseudomonas fluorescens (isolate-1) and botanicals viz., garlic clove extract 10% and neem leaf extract 10% significantly inhibited the growth of A. sesami under in vitro conditions. A total of seven seed treatments, comprising of two each of fungicides, bio-control agents and botanicals and untreated control, which were identified as the best treatments under in vitro conditions, were imposed for the management of Alternaria blight in sesame in pot culture. The observations on various seed quality parameters were recorded and the results revealed significant differences in germination (%), seedling length (cm) and seedling vigour index-I among different seed treatments as compared to control (untreated seeds). The variation in seedling vigour index-II was non-significant among different seed treatments. Sesame seed treated with combination product of carbendazim 12% + mancozeb 63% @ 0.2% recorded higher seed germination (98.75%), seedling length (16.80 cm), seedling vigour index-I (1659) and seedling vigour index-II (2.94) when compared to other treatments prior to sowing. Evaluation of selected fungicides, botanicals and bio-control agents against Alternaria leaf spot of sesame in pot culture showed that seed treatment with combination product of carbendazim 12% + mancozeb 63% @ 0.2% was effective in reducing the disease intensity (63.20%) of Alternaria leaf spot and also increase in plant height (44.11 cm), number of capsules per plant (12.53), seed yield per plant (2.23 g) and harvest index (14.17) when compared to control (without seed treatment). The observations recorded on various seed quality parameters of harvested seed from pot culture revealed significant differences among different seed treatments. Sesame seed harvested from seed treated with combination product of carbendazim 12% + mancozeb 63% @ 0.2% recorded highest seed germination (99.33%), seedling length (17.37 cm), seedling vigour index-I (1725) and seedling vigour index-II (3.97). Based on the present results it is concluded that seed treatment with combination product of carbendazim 12% + mancozeb 63% @ 0.2% reduces the seed borne infections besides improving yield and quality parameters in sesame.en-USnullThesis