EVALUATION OF FATTY-ACIDS IN OIL AS REAPING INDEXES FOR CARIBBEAN-GROWN GROUNDNUT (ARACHIS-HYPOGAEA)

Studies were conducted to evaluate amounts of fatty acids in the oil as possible indicators of crop maturity in the groundnut, cultivar NC2, grown in St Vincent, Eastern Caribbean. Percentage fatty acids in oil of the composite samples of seeds collected between 99 and 141 days after planting for a period of 3 years (1985-87) was determined by gas-liquid chromatography. Results indicated variation in the amounts of individual fatty acids with crop maturity. There were definite trends, however, with respect to oleic and linoleic acids. As seeds matured, percentage oleic acid increased and percentage linoleic acid decreased, and consequently, the oleic:linoleic acid ratio in oil of the composite seeds increased significantly. The percentage oleic acid peaked significantly at a value of 55.8 +/- 0.59 at optimum harvest dates. The results clearly suggested therefore that percentage oleic acid in oil could be used as a reliable reaping index for groundnut.