Submitted to: Plant Genetic Resources: Characterization and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 9, 2012
Publication Date: January 7, 2013
Repository URL: http://handle.nal.usda/gov/10113/58752
Citation: Jarret, R.L., Levy, I.J., Potter, T.L., Cermak, S.C., Merrick, L.C. 2013. Seed oil content and fatty acid composition in a genebank collection of Cucurbita moschata Duchesne and C. argyrosperma C. Huber. Plant Genetic Resources: Characterization and Utilization. 11:149-157. Interpretive Summary: The seeds of the various types of pumpkins and squashes are a real and potential source of oil. Seeds of butternut squash (Cucurbita moschata) and cushaw type pumpkins (Cucurbita argyrosperma) are good examples. Seed of both of these are used as a source of oil. The USDA/ARS maintains collections of numerous varieties of both of these species. This study examined the oil content in seed of the hundreds of these accessions of C. moschata and C. argyrosperma for both seed oil content and fatty acid composition. Seeds of C. moschata had a maximum of 34% oil with an average of ~ 28%. Seeds of C. argyrosperma had a maximum of 36 % with an average of ~29%. The primary fatty acid in C. moschata was determined to be linoleic acid with a maximum concentration of ~61% and a minimum of ~24%. In C. argyrosperrma linoleic acid reached a maximum of ~ 58% and a minimum of ~ 27%. Overall, the average oil content of seed of C. moschata was not significantly different from that of C. argyrosperma. Also, the fatty acid composition of the seed of both species was similar. The wide range in the concentrations of seed oil and fatty acid composition indicate that both of these variables can likely be enhanced to improve oil yields and nutritional value.
Technical Abstract: Data on intraspecific variability for seed oil content, fatty acid composition and seed oil characteristics in Cucurbita moschata and C. argyrosperma are lacking in the scientific literature. We examined 528 genebank accessions of C. moschata and 166 accessions of C. argyrosperma - that included members of both subsp. argyrosperma and subsp. sororia - for seed oil content and fatty acid composition. Oil of both species had near identical viscosities, viscosity indexes, color, and oxidative stabilities while oil of C. argyrosperma had a slightly higher pour point, cloud point, viscosity index, FFA value and AV when compared to C. moschata. Mean oil content values of the two species were similar at 28.7% +/- 2.8% and 29.2% +/- 2.6% for C. moschata and C. argyrosperma, respectively. The seed oil content of C. argyrosperma subsp argyrosperma var. callicarpa was significantly higher than that of the other taxa examined. The average (mean) percent of total seed weight attributable to the kernel was 77.2 % in C. moschata (n = 34) and 74.5 % in C. argyrosperma (n = 46). The percentage of total seed weight attributable to the hull was correlated with seed oil content, in both species. Linoleic was the predominant fatty acid in all samples analyzed. Means for individual fatty acids in C. moschata were linoleic - 48,5%, oleic – 22.6%, palmitic – 20.7% and stearic – 7.5%. Means for individual fatty acids in C. argyrosperma were linoleic – 47.3%, oleic – 27.5%, palmitic – 16.5% and stearic – 8.0%.