RELATIONSHIP OF SOYBEAN SEED QUALITY TO FATTY-ACID AND C-6-ALDEHYDE LEVELS DURING STORAGE

Lipid peroxidation is thought to be an important factor in seed deteri oration. This investigation was initiated to determine if changes in f ree fatty acids and peroxidation products are related to changes in se ed quality during soybean [Glycine max (L.), Merr.] seed deterioration , Seed lots of three soybean cultivars (Century, Pennyrile, and Pharao h) were stored at 20, 30, and 40 degrees C, sampled periodically, and tested for seed germination and vigor, Embryonic axes excised from det eriorated seeds were tested for contents of total and free fatty acids and C-6-aldetydes. Seed vigor, as measured by accelerated aging, cond uctivity, and cold tests, was the first seed quality component lost in all cultivars and storage environments, followed by a decline in perc entage germination, Conductivity of seed leachates increased about two -fold during storage for all cultivars, The amount of total fatty acid s in the lipid fraction did not change, while free linoleic and linole nic acids increased about two-fold during seed deterioration. E-2-hexe nal increased two-fold but hexanal did not change during storage, Both free linoleic acid and E-2-hexenal content were correlated with seed quality, bat little association was shown between lipoxygenase activit y and seed quality. Free fatty acids may have contributed to seed dete rioration by disrupting membranes and/or by toxicity of subsequent per oxidation products.