Comparative Seed Traits\u27 Profiling of Upland Cotton Line with Pima Cotton Chromosomal Substitutions

Cottonseeds are usually regarded as by-product of cotton farming, scientific studies primarily focused only on improving the fiber traits. This study focuses on establishing cottonseeds as an important source of food and feed and also supporting future research works aimed at improving cottonseed nutritional traits. Cottonseeds are rich in protein (23%) and fat (20%) are crushed to obtain oil which contains 70% unsaturated and 26% saturated fatty acids. The pressed seeds retain the crude fiber (25%), which are used as animal feed, being valuable digestive source usually for dairy cows. Cottonseeds also contain gossypol, responsible for natural defense of cotton against insect, pests, rats and diseases, but have anti-nutritional effects when present in oil or pressed seed. This research profiled seed traits of cotton chromosomal substitution (CS-B) lines by the use of Fourier Transform Infrared Spectroscopy (FTIR) as well as High Performance Liquid Chromatography (HPLC) and compared them separately for hull and kernel. Four functional groups (lipid, protein, phenol and phosphate) were detected in these lines at the light wavenumber range of 1700-1750 cm-1, 1600-1700 cm-1, 1420-1480 cm-1 and 1050-1150 cm-1, respectively. Lipid and protein secondary structures were detected by calculating area under the curve in mature cottonseeds using FTIR. Based on secondary structures, various differences were observed among the cottonseeds. The progeny lines CS-B06, CS-B15sh and CS-B16 had different structures than both the parents while CS-B12 and CS-B22sh retained similarity to both the parents. On the other hand, CS-B05sh, CS-B07 and CS-B26 were inclined towards TM-1 parent while CS-B02 and CS-B04 had similar structures to that of 3-79 parent. Though HPLC protocols for determining gossypol contents could not be established, detectability of hydrated and dehydrated lipids and different protein secondary structures in these cottonseeds non-destructively is a novel finding of this project. Every line showed presence for both lipid and protein in their hull and kernel while they showed variable evidences for phenol and phosphate. These organic compounds are valuable source of food and feed for humans and livestock, thus CS-B lines demonstrated their potential to be grown also for seed products. The results may help plant breeders to enhance the production of cottonseeds from selected CS-B lines for their use as highly nutritious food and feed sources