Estimation of Current Cottonseed-Fiber Ratios, Seed Indices, and Seed Tissue and Compositional Properties

Because of the sustained efforts to breed cotton for increased fiber yield, several seed/fiber compositional properties have likely shifted over the decades.  Conversations with breeders, ginners, and oil processers have identified a number of concerns, including reduced seed size, weaker hulls, greater levels of fiber contamination, and reduced kernel protein levels - all of which affect current processing practice.  To better understand these changes, a series of field cotton varieties was collected from areas around Stoneville, MS; Lubbock, TX; and Las Cruces, NM.  The samples were ginned and cleaned to determine seed-to-fiber ratios, weighed to estimate deed indexes, hand dissected to determine the proportions of linter, hull and kernel and analyzed for gossypol, oil, and protein.  Results from the first two years of the study indicated that the average fiber/seed ratio was 1.43+/- 0.12 on an as is basis and and declined compared with published data from the 1930s and 40s.  Seed indices showed  a similar decline with early published data. Seed tissue proportions have changed less, although a decrease in the percentage of linters was apparent.  A third year of study on an expanded number of varieties is planned.