Varying Planting Dates or Irrigation Regimes Alters Cottonseed Composition

Abstract

Despite continued utilization of cottonseed (Gossypium hirsutum L.), little information exists regarding the effect of production factors on cottonseed composition. The objective of this study was to determine how irrigation regime and planting date affect cottonseed composition. Six cotton cultivars were planted early (late April) and at a normal time (late May) in a field near Stoneville, MS, from 2005 to 2008. Half of the plots were irrigated and half were cultivated dry. Seed from the 2006 through 2008 seasons were analyzed for protein, crude oil, gossypol, soluble carbohydrates, and the oil's fatty acid composition. Irrigation increased oil and total soluble carbohydrate levels by 7 and 4%, respectively, and reduced protein levels by 10%. Irrigation also increased the level of total gossypol by 21%, modestly decreased the percentage of the gossypol (+) isomer, and slightly decreased the level of saturated fatty acids in the oil. Early planting decreased gossypol in the seed kernel by 8% under dryland conditions but not under irrigated conditions. The early planting effect on the fatty acid distribution was similar to the effect observed under dryland conditions, but the differences were more modest. Early planting and irrigation offer potential for improved fiber and seed yield but with altered seed composition. Given the proper economic incentives, producers could alter some production strategies to produce seed with more valuable composition traits.