Compositional Screening of Cottonseed Germplasm.

A collection of 416 cottonseed samples representing 27 Acala, 275 Pima, and 114 Upland genotypes were analyzed for oil composition and gossypol content.  Pima cottonseed had the highest average percent oil content (22.3%), while the Acala and Upland cottonseeds contained 18.1% and 17.1% oil, respectively.  Cottonseed oil from the Acala lines had the highest average total tocopherol content (619 ug/g oil), followed by the Upland cottons (574 ug/g oil), and Pima cottons (352 ug/g oil).  Oil from Pima cottons contained a higher proportion of gamma tocopherol than alpha tocopherol (G/A ratio of 1.41), while Acala oil had almost equal portions, and Upland cotton a higher proportion of alpha tocopherol (G/A ration of 0.69).  All three cottons had similar levels of palmitic acid (22.7-22.9%).  Pima cottons had lower levels of linolenic acid (48.9%) than Acala or Upland cottons (~53%). Pima cottonseeds contained the highest levels of gossypol (10,000 ug/g), followed by Upland (9,080 ug/g) and Acala (6,769 ug/g).  Within each cotton class, a wide range of variability was found for all measured components.  These results suggest that cottonseed has genetic variability for compositional factors that could be exploited through breeding.