Genetic and agro-climatic variability in seed fatty acid profiles of Akebia trifoliata (Lardizabalaceae) in China

[Display omitted] •SFA:MUFA:PUFA in A. trifoliata (AT) seed oil presents the desired golden ratio 1:1.5:1.•Northern AT, rich in oil and OA, and low in PA and LA, is opposite to southern AT.•Latitude, temperature and moisture are core factors affect oil production in AT.•Colder and drier zones of cluster III are more desirable for oil production in AT. This study first systematically investigated the differences and correlations of seed oil content, fatty acid (FA) composition and regional agro-climate conditions of Akebia trifoliata from 25 representative distribution areas throughout China. A. trifoliata seeds were rich in oil (30.2 %–48.8 %), but significant (P < 0.01) variations were detected among their FA profiles. Ten major FAs, dominated by oleic acid (OA, 155.9-261.5 mg g−1, 36.6 %–45.2 %), linoleic acid (LA, 113.8–156.4 mg g−1, 23.5 %–30.8 %) and palmitic acid (PA, 101.8–149.1 mg g−1, 20.3 %–25.7 %), were detected and quantified by GC–MS. Noticeably, their ratios of saturated: monounsaturated: polyunsaturated FAs were 1:1.5:1, which was in line with the World Health Organization's recommendation. Latitude, temperature and moisture were the core factors affecting oil accumulation in A. trifoliata. Opposite to PA and LA, the OA and oil content were strongly negatively correlated with high temperature and precipitation, and were higher in northern and eastern seeds. According to the results of correlation and cluster analysis, A. trifoliata germplasms and agro-climate characters of six regions (from cluster III) around latitude 35 °N, where were much colder and drier, and with larger diurnal temperature fluctuations than other regions, were more desirable for commercial cultivation of A. trifoliata for oil processing and for breeding of improved cultivars.