Author
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Scheffler, Jodi |
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Romano, Gabriela |
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Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/5/2008 Publication Date: 10/1/2008 Citation: Scheffler, J.A., Romano, G.B. 2008. Modifying gossypol in cotton (Gossypium hirsutum L.): a cost effective method for small seed samples. Journal of Cotton Science. 12(3):202-209. Interpretive Summary: Cotton (Gossypium hirsutum L.) has pigment glands throughout the vegetative and reproductive parts of the plant, and these glands contain a compound called gossypol. This compound has been reported to have anti-tumor activity, but it also has an anti-nutritional factor that can adversely affect mammals. The seed contains 23% protein, but is not widely used because of the gossypol. Currently there is interest in developing low gossypol varieties to use in animal feed and to develop high gossypol lines to use for cancer research. Projects to modify gossypol content in cotton seeds, require a rapid, cost effective analysis method that uses small amounts of seed. To address this need, we developed a scaled down version of the total gossypol American Oil Chemists’ Society (AOCS) Official Method with a simplified procedure for preparing the seed for analysis. It allows handling large numbers of samples and gives consistent results over laboratory replications. Analysis of seed samples, grown over three years, indicated that using this method makes it possible to reliably select for gossypol content in plants grown under field conditions. Using this method, it is possible to test for gossypol content in early generations of a cotton variety development program, and this will promote the development of new cotton varieties with modified seed gossypol content. Technical Abstract: Cotton (Gossypium hirsutum L.) has pigment glands throughout the vegetative and reproductive parts of the plant and these glands contain a polyphenolic compound called gossypol. This compound has been reported to have anti-tumor activity. However, it also acts as an anti-nutritional factor that can adversely affect mammals and limit it’s use as animal feed. Research projects to modify gossypol content in cotton seeds, require a rapid, cost effective analysis method that uses small amounts of seed. The objective was to develop a scaled down version of the total gossypol American Oil Chemists’ Society (AOCS) Official Method Ba 8a-99 with a new method for preparing the seed for analysis, and the flexibility to analyze the samples for total gossypol or the (+)/(-)forms of gossypol. When comparing samples ranging from 100 mg to 6.25 mg, the 100 mg sample size was the most reproducible. The AOCS Official Method uses a dry de-hulling method to separate the hulls from the rest of the seed. A comparison of dry versus our simplified wet de-hulling method showed the values for the dry and wet methods were similar, but the wet values were consistently slightly higher than the dry de-hulled samples. Decreasing the sample weight to 100 mg lowered the cost by 32%. At the 25 mg sample scale, the cost was reduced to 1.287/sample, a 55% savings. If only total gossypol is of interest, then these costs can be further reduced by substituting 3-amino-1-propanol for (R)-(-)-2-amino-1-propanol in the method. To make progress in a gossypol modification project, the method must give consistent results across years. Results generated using this method, demonstrated that while the exact percentages varied across years, in general the values were consistent for each variety or line. We have developed a scaled down version of the total gossypol AOCS Official Method Ba 8a-99 with a simplified protocol for preparing the seed for analysis. The method allows large numbers of samples to be processed and gives consistent results over laboratory replications. Analysis of seed samples over three years indicated that using our method, it is possible to reliably select for gossypol content in plants grown under field conditions. |
