Enhanced seed yield, essential amino acids and unsaturated fatty acids in soybean seeds with phosphorus fertilizer supply

This study aimed to understand the role of phosphorus (P) in soybean yield and quality, particularly amino acids and fatty acids. Field trials were undertaken using 56 soybean genotypes, including 12 landraces, 36 commercial cultivars and 8 advanced breeding lines. The results showed the response of seed yield (+20%) to P supply was higher than the protein (+1.5%) and oil (–1.5%) content. Phosphorus supply explained 80.5%, 11.4% and 50.6% variation of seed yield, oil and protein content, respectively. Five out of eight essential amino acids were significantly increased with P supply. Phosphorus supply resulted in a significant increase in oleic acid but a decrease in linoleic acid, as well as a decrease in saturated and an increase in unsaturated fatty acids. Phosphorus supply accounted for 30.9% and 33.9% variation in essential and non-essential amino acids, and 5.1% and 27.9% variation in saturated and unsaturated fatty acids, respectively. We concluded (1) both yield and soybean seed quality can be improved with P fertilizer supply; (2) the seed nutritional quality improved by increasing the concentration of essential amino acids and proportion of unsaturated fatty acids. These findings emphasized the importance of P management guidance to simultaneously increase yield and food nutritional value.