Influences of agricultural practices, environment, and cultivar differences on soybean seed protein, oil, sugars, and amino acids

Authors: Bellaloui, Nacer; MCCLURE, ANGELA - University Of Tennessee; Mengistu, Alemu; Abbas, Hamed

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2020
Publication Date: 3/19/2020
Citation: Bellaloui, N., McClure, A.M., Mengistu, A., Abbas, H.K. 2020. Influences of agricultural practices, environment, and cultivar differences on soybean seed protein, oil, sugars, and amino acids. Plants. 9(3),378. https://doi.org/10.3390/plants9030378.
DOI: https://doi.org/10.3390/plants9030378

Interpretive Summary: Seed composition constituents (protein, oil, fatty acids, sugars, and amino acids) determine the nutritional quality of soybean seed. Information on the effects of agricultural practices such as seeding rate, row-spacing, herbicide application, and nitrogen fertilizer on seed composition is limited. Therefore, the objective of this research was to investigate the effects of these factors on seed composition constituents. Two field experiments were conducted in 2015 and 2016 at the Milan Research and Education Center in Jackson, Tennessee, USA. Two soybean cultivars (AG 4632 and Pioneer 47T36) were grown, and different rates of seeding rate, row-spacing, nitrogen fertilizer, and herbicide were used. The results showed significant effects of all of these agricultural practices on some seed composition constituents, including protein, fatty acids, sugars, and amino acids, though these effects were not always consistent across years and cultivars. The current research demonstrated that agricultural practices can alter some seed constituents. This research is beneficial to soybean breeders and physiologists to advance our knowledge on the interactions between agricultural practices and seed composition, and to agronomists and producers to identify the best agricultural management practices to maintain high seed nutritional qualities.

Technical Abstract: Information on the effects of agricultural practices such as seeding rate (S), row-spacing (RS), herbicide apical treatment (T), and nitrogen application (N) on soybean seed composition (protein, oil, fatty acids, sugars, amino acids) is limited. Although seed composition constituents are genetically controlled, it has been consistently shown that agricultural practices and environmental conditions significantly influenced the amount and profile of seed composition. Therefore, understanding the responses of these seed composition constituents to these practices and environmental conditions is critical to maintain high seed nutritional qualities. Two field experiments were conducted in 2015 and 2016 at Milan Research and Education Center (MREC), Milan, TN, USA. The experiments were irrigated with 4 replications of the following treatments in a split-plot design: Two soybean cultivars (AG 4632 and Pioneer 47T36), two seeding rates at 100,000 seeds ac-1 (40,000 seeds ha-1) (40K) and 140,000 seeds ac-1 (56,000 seeds ha-1) (56K); three row-spacing [(15 inches (40 cm) 2:1 twin-row; 15 inches (40 cm) row-spacing; 30 inches (76 cm) row-spacing)]; two N rates (0, 150 lbs N ac-1) (0, 168 kg ha-1, respectively); and Cobra herbicide (lactofen) (12 oz/ac) (0.88 liters ha-1). The results showed significant effects of S, RS, T, and N on some seed composition constituents. For example, in 2015 in AG 4632 and on twin-row, protein, linoleic acid, and sucrose contents were higher at 40K seeding rate than at 56K rate. However, stearic, oleic, and linolenic acid were higher at 56K rate than at 40K rate. Also, amino acids responded differently; for example, aspartic acid (ASP), serine (SER), glycine (GLY), and arginine (ARG) were higher at 56K rate than at 40K. Different constituents responded differently in each year and in each cultivar due to environmental conditions and cultivar differences. The current research demonstrated that agricultural practices can alter some seed nutrients. This research is beneficial to breeders and physiologists to advance our knowledge on the interactions between cultivars and environment for seed nutritional quality selection, and to agronomists and producers to consider best agricultural management to maintain high seed nutritional qualities.