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Subject: Crop Physiology × End date: 2020 × Start date: 2020 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    EFFECT OF JATROPHA LEAF EXTRACT AND SEED OIL ON OKRA (Abelmoschus esculentus L.)
    (AAU, Jorhat, 2020-08) Malsawmzuala, Jeffrey; Das, K.
    Jatropha curcas is a woody shrub that is projected to be one of the best sources for bio-diesel as it can be grown in diverse climatic conditions. However, it is also known to exhibit allelopathic and phytotoxic effects to nearby plants. The seed oil is known to be a potent source for biopesticide formulations due to its toxicity but its possible allelopathic effects on the recipient crop has not been properly explored. A series of experiments were conducted during July 2018 to October 2018 to test the possible allelopathic effects of jatropha leaf extract and seed oil on okra (Abelmoschus esculentus L.). In two separate experiments, aqueous extracts of jatropha leaf at 2.5%, 5.0%, 10.0% and 15.0% (W/V) concentrations and jatropha seed oil at 1.0%, 2.5%, 5.0%, 7.5% and 10.0% (V/V) concentrations were bio-assayed against germination and seedling growth of okra. In both the cases, germination percentage, germination index, root and shoot length, fresh and dry weights of root and shoot and vigour index were found to be significantly reduced by both the leaf extract and seed oil. Seed oil exhibited higher inhibitory effects than aqueous leaf extract. Two other separate pot culture experiments were conducted with both aqueous leaf extract and seed oil of jatropha at the same range of concentrations as employed in the above mentioned experiments to evaluate growth and yield of okra. In both the cases, significant reduction in plant height, leaf number, leaf area, root volume, dry weights of root and shoot, total leaf chlorophyll content, fresh and dry weights of pods were recorded. Different growth parameters of the crop were found to respond differentially to aqueous leaf extract and seed oil of jatropha. Higher reduction of pod fresh weight (yield) was recorded in aqueous leaf extract (25.37% inhibition over control) in comparison to seed oil (12.18% inhibition over control) at their highest applied concentrations. All inhibitory effects of both aqueous leaf extract and seed oil were found to be concentration dependent. In conclusion, seed oil was found to be more inhibitory in laboratory bioassay while final yield of okra was reduced more by the aqueous leaf extract of jatropha.