Quality of Ocimum Gratissimum treated soyabean seeds under different storage conditions

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Soyabean seeds are often associated with problems of germination and plant establishment as a result of rapid loss of viability caused by mycoflora during storage. In this study, attempt was made to isolate and identify the mycoflora associated with stored Anidaso and Bengbie seeds and to ascertain a possible storage method aimed at arresting rapid deterioration and subsequent loss of seed viability. Ocimum gratissimum leaf and seed powders were both prepared by milling 200g each of sun-dried leaves and seeds. The leaves and seeds were sun-dried for 2 weeks before milling. The powders were used immediately after preparation. Freshly harvested hand- threshed soyabean seeds were surface disinfected with 2.5% Sodium hypochiorite and 40% ethanol and dried in forced-air oven. Anidaso and Bengbie seeds treated with both powders and Dithane M-45 were stored in heat-sealed polythene bags and paper bags under ambient conditions for 9 months. Nine (9) genera of fungi were isolated and their percentage occurrence recorded. The main genera of fungi isolated were Aspergillus, Penicillium, Fusarium and Mucor. The location of seed-borne mycoflora affected seed viability especially in seeds which had their embryo infected with fungi. Increase in seed moisture as well as storage period directly affected the rate of fungal occurrence as well as decline in seed germination. The O. gratissimum leaf powder, when used to treat seeds which were stored in polythene bags, suppressed the rapid deterioration of the seeds and maintained viability. This compared favourably with Dithane M-45 treated seeds stored in sealed polythene bag.
A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the award of the Degree of Master of Philosophy in Plant Pathology, 1994