Natural variation in fatty acid composition of Sapindus spp. seed oils

Sapindus mukorossi and Sapindus delavayi seeds were collected from 60 populations distributed over a wide geographic area (a range of 12.0° latitude, 19.0° longitude, and 1800 m elevation) across southern China. The variation in fatty acid composition of seed kernel oil between the two species and among individuals was determined, and relationships with geographical and environmental factors were analyzed. The oil characterization allowed the identification and the quantification of 12 fatty acids. The C16-C20 fatty acids accounted for more than 98% of the total content, of which oleic acid was the most abundant (more than 50%). The fatty acid composition was generally stable between the two species and among individuals despite the wide geographic range from which the samples were collected, and the oil showed good potential for biodiesel production. Oleic acid showed insensitivity to environmental factors. Correlation analysis showed that environmental factors had a strong influence on the composition of other fatty acids, such as C20:1 (20.95%), C18:2 (7.56%), C20:0 (6.01%), and C16:0 (4.55%), and explained 36.68% of the total variance. Among the environmental factors, elevation, maximum temperature, and precipitation significantly contributed to variation in seed kernel oil fatty acid composition among populations. Furthermore, the cooperativity of elevation and maximum explained 30.13% of the variance (P < 0.01). Thus, environmental factors, especially elevation, maximum temperature, and precipitation, of the original provenance should be considered during genotype selection.