Estimation of current cottonseed-fiber ratios, seed indices, and seed tissue and compositional properties

Authors: Dowd, Michael; Pelitire, Scott; Delhom, Chris

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/2/2017
Publication Date: 3/1/2017
Citation: Dowd, M.K., Pelitire, S.M., Delhom, C.D. 2017. Estimation of current cottonseed-fiber ratios, seed indices, and seed tissues and compositional properties. In: Proceedings of 2017 Beltwide Cotton Conferences, Dallas, TX, January 4-6, 2017. p. 839-844.

Interpretive Summary: Because of the intensive breeding of cotton for increased fiber yield, there have likely been changes to the seed properties and composition. This work was undertaken to better understand how seed traits have changes compared with early reports. The work showed that seed-to-fiber ratio has changed dramatically, and seed size has also decreased significantly. Smaller changes were observed for the distribution of linters, hull and kernel but no obvious effects were found regarding the kernel oil or protein composition. The work will be of interest to farmers, ginners, and oil processors as well as researchers working on seed quality issues.

Technical Abstract: 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 directly affects the economic value of the current processing practice and the value of the seed for direct feeding to dairy cows. 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 ratio, weighed to give seed index, and hand-dissected to determine the proportions of linter, hull, and kernel. Kernels were then analyzed for gossypol, oil, and protein. Results from the first two years of study (2014 and 2015) indicated that the average seed/fiber ratio was 1.44 ± 0.10 (range: 1.28–1.60, as is basis) and has declined compared with published data from the 1930s and 1940s. Seed indices averaged 9.90 ± 1.11 g (range: 8.46–11.8 g, as is basis) and showed a similar decline compared with early published varietal data. Seed tissue proportions have changed less, although a decrease in the percentage of linters was apparent. A third year of study is in progress.