Location: Crop Genetics ResearchTitle: Effects of row-type, row-spacing, seeding rate, soil-type, and cultivar differences on soybean seed nutrition under US Mississippi Delta conditions
Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2015
Publication Date: 6/10/2015
Citation: Bellaloui, N., Bruns, H.A., Abbas, H.K., Mengistu, A., Fisher, D.K., Reddy, K.N. 2015. Effects of row-type, row-spacing, seeding rate, soil-type, and cultivar differences on soybean seed nutrition under US Mississippi Delta conditions. PLoS One. 10(6):e0129913. doi:10.1371/journal.pone.0129913.
Interpretive Summary: Seed nutrition determines seed quality. Very little information is available on the effects of single-row and twin-row planting on seed composition and mineral nutrition. The objective of this research was to evaluate the effects of single-row and twin-row planting on seed protein, oil, fatty acids, sugars (sucrose, raffinose, stachyose, glucose, and fructose), and minerals (phosphorus, boron, and iron). Two field experiments were conducted; one experiment was conducted in Sharkey clay soil in 2009 and 2010, and the other in Beulah fine sandy loam soil in 2008, 2009, and 2010 under irrigated conditions. Soybean were grown on 102 cm single-rows and on 25 cm twin-rows with 102 cm centers at seeding rates of 20, 30, 40, and 50 seeds per square meter. Two soybean cultivars (94M80 and PG 533) were used. Results showed that increasing seeding rate resulted in increases of protein, sucrose, glucose, raffinose, phosphorus, and boron concentrations. However, this increase became either constant or declined at the higher rates (40 and 50 seeds per square meter). Cultivars responded differently to seeding rate and row-type. Cultivar 94M80 had the highest concentration of oleic fatty acid in 2010, probably due to high heat and drier conditions in 2010. There were inconsistent patterns for the rest of the seed constituents. Sucrose, raffinose, glucose, and fructose concentrations were positively correlated with seeding rate in 94M80 andPG-533 in both clay and sandy soils, although this correlation was dependent on row-type, soil type, and cultivar. There were no clear responses of seed constituent concentrations to seeding rate or row-type in 2010 due to high temperature and drought. It is concluded that seeding rate and row-type can alter seed composition and minerals, and seeding rate beyond 40 and 50 seeds per square meter may not result in higher seed qualities, especially under high heat and drought conditions as in the Mid-southern U.S.
Technical Abstract: Management practices such as seeding rate (SR), planting date (PD), and row-type (RT: single- and twin-rows) may alter seed nutrition in soybean. The objective of this research was to investigate the effects of SR and PD on soybean seed composition (protein, oil, fatty acids, and sugars) and minerals (B, P, and Fe) grown in single- and twin-rows in the Mississippi Delta region of mid-south. Two field experiments were conducted in 2009 and 2010 on Sharkey clay and Beulah fine sandy loam soil at Stoneville, MS, under irrigated conditions. Soybean were grown on 102 cm single-rows and 25 cm twin-rows on 102 cm centers at seeding rates of 20, 30, 40, and 50 seeds m–2. Results showed that protein, glucose, P, and B concentrations increased with increased SR, but that the concentrations remained constant or declined at the highest seeding rates (40 and 50 seeds m–2). Palmitic, stearic, and linoleic acid concentrations were least responsive to increased SR. Early planting (April planting) resulted in higher oil, oleic acid, sucrose, B, and P on both single and twin-rows. Late planting (June planting) resulted in higher protein and linolenic acid, but lower oleic acid and oil concentrations. A significant (P=0.05) positive correlation between SR and B, Fe, and linolenic acid was observed. A negative correlation between SR and oleic acid was observed only in sandy soil. Our research demonstrated that SR, RT, and PD altered seed constituents, but the level of this alteration was dependent on SR, RT, and PD. The changes in seed constituent concentrations could be due to significant changes in environmental factors, especially temperature, nutrient uptake and accumulation in seeds, early canopy closure, and higher light interception resulting from increased SR. This information benefits growers and breeders for considering environmental factors such as heat and agronomic practices.