Effect of Cultivation Methods on Seed Yield Traits, Oil Yield, and Fatty Acid Compositions of Cultivated Paeonia ostii

Paeonia ostii is recognized as an important oilseed tree peony species with potential as a raw material source for cosmetic and health care products, strong seed setting capacity, high seed oil yield, and abundant omega-3 polyunsaturated fatty acids. P. ostii, commonly called Fengdan, is widely cultivated in China. The cultivation method difference has an important influence on the oil-use feature, which is a key index for evaluating the quality of oilseed crops. This study aimed to select an optimal cultivationmethod toprovide the first reference data for high-yield and high-quality seed oil harvesting and to facilitate the understanding of the quality difference in the formation mechanism of seed oil in cultivated P. ostii. This study selected five representative cultivationmethods, open field cultivation, sunny slope cultivation, shady slope cultivation, understory intercropping cultivation, and high-altitude cultivation, and investigated the influence of cultivation method differences on the oil-use feature based on the three aspects of seed yield traits, oil yield, and fatty acid compositions. Six seed yield traits (fruit pod length, fruit pod width, fruit pod thickness, number of fruit pods per plant, 1000-grain weight, and seed yield per plant) and oil yield reached the maximum values of 7.75 cm, 6.99 cm, 1.57 cm, 11.33, 290.45 g, 85.8 g, and 30.41%, respectively, using the understory intercropping cultivationmethod. Fatty acid compositions weremainly identified as alpha-linolenic acid, linoleic acid, oleic acid, stearic acid, and palmitic acid, with significant content differences among different cultivation methods (P < 0.05). Functional component alpha-linolenic acid and total amounts of unsaturated fatty acids reached the maximum values of 46.85% and 65.23%, respectively, with high-altitude cultivation and understory intercropping cultivation. The seed yield traits, oil yield, and total amounts of unsaturated fatty acids were optimal with the understory intercropping cultivation method, whereas high-altitude cultivation was conducive to the accumulation of alpha-linolenic acid. Understory intercropping cultivation with appropriate altitude increases is recommended as a preponderant cultivation method for high-yield and high-quality seed oil harvesting for this crop.