Seed-Fiber Ratio, Seed Index, And Seed Tissue and Compositional Properties Of Current Cotton Cultivars

Because of the continual 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 several concerns, including smaller seed size, weaker hulls, increased seed and hull fragment contamination of fiber, and reduced seed oil and protein levels—all of which directly affect the economic value of the crop. To better understand these changes, field cotton samples of current cultivars were collected from areas around Stoneville, MS; Lubbock, TX; and Las Cruces, NM. The samples were ginned and cleaned to determine seed-to-fiber ratio, seed index, and the proportions of linter, hull, and kernel tissues. Kernels were then analyzed for oil, protein, and gossypol. Results from the three-year study (2014 through 2016) indicated that the average seed-to-fiber ratio was 1.41 ± 0.11 (range: 1.19–1.61, as is basis) and has declined compared with data sets published prior to 1950. Of the varieties included in the study, seed index averaged 9.75 ± 0.99 g (range: 8.08–11.8 g, as is basis) and also showed an overall decline compared with early published data. Seed tissue proportions have changed less, although a decrease in the percentage of linters was apparent. The average level of seed oil and protein does not appear to have changed much over the years, although oil levels were very low for a few individual cultivars.