Diversity in seed oil content and fatty acid composition in three tree peony species with potential as sources of omega-3 fatty acids

Tree peony (Paeonia sect. Moutan) has long been known as a horticultural and medicinal plant in China. Recent studies have shown that tree peony may have further potential applications in the field of edible oils. The selection and cultivation of acceptable varieties is a key issue. Seed from 21 genotypes belonging to P. ostii, P. rockii, and P. ludlowii were evaluated for their oil contents and fatty acid compositions. The results indicated that the average oil contents of P. ostii, P. rockii, and P. ludlowii were 28.05%, 30.52%, and 27.62% (w/w), respectively. Averaged over all genotypes, the major fatty acid components in the seed oils of all three species were the unsaturated fatty acids, linolenic [28.10-52.57% (w/w)], linoleic [14.19-23.92% (w/w)], and oleic [22.67-43.55% (w/w)] acids. Oil contents and fatty acid compositions varied significantly between species, as well as between genotypes within a species. This indicated that tree peony could become an important source of edible vegetable oils and a novel source of omega-3 fatty acids. Germplasm collections will be important for future oil-rich tree peony breeding programmes.