Lakpale, N.Banjare, Vipin KumarKhare, N.Sharma, PraveenChandrakar, G.Khare, C.P.2022-03-242022-03-242021https://krishikosh.egranth.ac.in/handle/1/5810183773DETECTION OF SEED BORNE MYCOFLORA ASSOCIATED WITH ONION (Allium cepa L.) SEEDS AND THEIR MANAGEMENTThe present investigation was carried out in the Dept. of Plant Pathology, College of Agriculture, IGKV, Raipur (C.G.) during 2020-21. Seed health evaluation was attempted for seed lots of different onion varieties viz. Bhima super, Bhima Shubhra, Bhima dark red, Nashik red and one local variety collected from randomly selected village. In dry seed examination, seed lots of different onion varieties showed distinct variation in healthy seeds, damaged, discoloured, small/under sized, shrunken seeds, weed seeds and other inert materials. Washing test was also performed. Maximum spore load of associated seed borne mycoflora was observed in seed lot of local variety. Ten seed borne mycoflora viz., A. niger, A. flavus, Rhizopus stolonifer, Helminthosporium sp., Curvularia lunata, Chaetomium globosum, Penicillium sp., Fusarium sp., Alternaria porri, and Mycelia sterilia were detected and identified from the seeds of five onion varieties by using standard blotter, agar plate, rolled paper towel, washing test and deep freeze method. Many seed borne micro-organisms were capable of causing discolouration, shrivelling, distortions, spotting and stromatisation of seeds which were visible to the naked eye and this was the concern to the growers. In all incubation methods frequency of detected mycoflora differ. A. niger, A. flavus, Rhizopus stolonifer, Curvularia lunata and Chaetomium globosum detected in all incubation methods whereas Fusarium sp. detected only in deep freeze method and Mycelia sterilia detected in two methods deep freeze and agar plate. Highest frequency of mycoflora recorded of A. niger, A. flavus and Chaetomium globosum in all methods. In roll paper towel method, abnormal deformed seedlings, dead/mouldy seeds, hard seeds percentage were less recorded in local variety and intact seedlings percentage recorded high in local variety. Seedling vigour was markedly reduced by all of the seed borne mycoflora when evaluated by seed inoculation method. Efficacy of seed treatment by aqueous plant extracts revealed that, some are increasing and some are decreasing seedling vigour index of onion. Total fifteen plant extracts were taken for study and among them seedling vigour index was most favoured by Aristolochia (162.13%) followed by Doob grass (131.95%) and Jamun (-40%) retards the seedling vigour most among the plant extracts. Fungicidal seed treatment result revealed that propineb 70% was found best in all varieties. Trichoderma viride is a bio agent was given good result in increasing seedling vigour index as compared to that of control. Comparative account of seed borne mycoflora detected revealed that, higher frequency of mycoflora detected in deep freeze method (54.40%) followed by standard blotter method (38.40%), rolled paper towel method (37.40%) and less in agar plate method (16.80%). Frequency of mycoflora observed high in Bhima super variety (44.25%) and less in Bhima dark red variety (28.00%).EnglishThesis