Determination of Lipid in Cotton Chromosomal Substitution Lines By Fourier Transform Infrared Spectroscopy

Current studies emphasize the importance of cottonseeds which were generally considered only as the by-product now as source of cooking oil for human consumption. This research analyzed lipid contents in hulls and kernels from seeds of TM-1 (Upland cotton, Gossypium hirsutum), 3-79 (Pima cotton, G. barbadense) and 17 G. hirsutum lines substituted with chromosome or long (lo) and short (sh) chromosome segments from G. barbadense (CS-B): CS-B01, CS-B02, CS-B04, CS-B05sh, CS-B06, CS-B07, CS-B11sh, CS-B12sh, CS-B14sh, CS-B15sh, CS-B16, CS-B17, CS-B18, CS-B22lo, CS-B22sh, CS-B25 and CS-B26lo. Mature cottonseeds were cut into thin pieces with a razor blade and then placed on a NicoletTMisTM10 Fourier Transform Infrared Spectrometer (Thermo Fisher Scientific, Waltham, MA, USA) to record an average of 16 scans for each sample through OMNIC (v8.0) software. For each spectrum, wavenumbers were selected in the range of 4000 to 1000 cm-1 and corrected against background, as well as smoothened in SPECTRUM (v3.02) software three times to improve the quality. Area under curve was calculated from 1750 to 1700 cm-1 after peak resolving and peak fitting was done by Gaussian function in OMNIC. Pima parent (3-79) showed higher lipid content than Upland parent (TM-1) in hull but lower in kernel. CS-B12sh, CS-B17, CS-B22sh and CS-B26lo revealed both the hydrated and dehydrated types of lipid in their hulls while only the CS-B16 kernel revealed the dehydrated type. All CS-B lines were evaluated for their potential as source for extracting cooking oil, thus understanding the mechanism of lipid variation between these lines will allow us to effectively select suitable candidates for breeding programs.