Natural infraspecific variation in fatty acid composition of Cuphea (Lythraceae) seed oils

Fatty acid analyses of seed lipids were performed for 28 populations representing three widely distributed Cuphea species. Locality and climatic data for all samples were also compiled. The objectives of this study were to examine the extent of variation in seed oil composition among the wild populations, and to discover any patterns of relationship between fatty acid composition of seed oils and environmental factors. While we found the dominant fatty acid in the oil of each species remained consistent over the environmental and geographical ranges of the samples in the present study, variation as high as 30.6% in the amount of the dominant fatty acid produced was observed. Correlation analysis between fatty acid composition and the individual environmental factors of latitude, elevation or temperature showed no consistent pattern of influence. However, when considered together, the interaction of all three, and especially latitude and elevation, contributed significantly to the variation among populations. Environmental data at microhabitat level and through controlled environmental experiments will be needed for more precise understanding of factors affecting Cuphea seed oil composition at the population level.