Effect of Seed Orientation, Nakedness, Seed Moisture, and Cultivar on Cottonseed Hull Compressive Strength

Cottonseed strength is an important concern for ginners and oil processers. Seed that becomes damaged during handling or processing affects the value of both the seed and fiber. To develop a tool to allow better determination of the potential for seed damage, seed compressive strength was studied with an Instron material tester. Individual seeds were compressed until they fractured. The effects of seed orientation, acid delinting, and seed moisture were studied, and a series of cultivars were investigated. Seed cracked with less force when oriented horizontally than when they were oriented vertically in the tester. Seeds had a higher compressive strength when they were dryer. Differences in atmospheric relative humidity (35 to 65%) were enough to effect the testing results, indicating that seed needed conditions before testing. Varietal differences in seed compressive strength were apparent. While the technique is useful for evaluating differences in seed strength, it may not be ideal for determining the potential for seed to be damaged during processing because of the variance associated with the measurement and the large number of seeds that need to be processed. A better test might be some form of mechanical damaging devise (e.g., a roller mill) that would allow the simultaneous analysis of a representative population of seed.