Agricultural practices altered soybean seed protein, oil, fatty acids, sugars, and minerals in the Midsouth USA.

Nacer Bellaloui,Hamed K Abbas,Daniel K Fisher,H Arnold Bruns,Krishna N Reddy,Alemu Mengistu

doi:10.3389/fpls.2015.00031

Nacer Bellaloui, Hamed K Abbas + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2015.00031

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Abstract

Information on the effects of management practices on soybean seed composition is scarce. Therefore, the objective of this research was to investigate the effects of planting date (PD) and seeding rate (SR) on seed composition (protein, oil, fatty acids, and sugars) and seed minerals (B, P, and Fe) in soybean grown in two row-types (RTs) on the Mississippi Delta region of the Midsouth USA. Two field experiments were conducted in 2009 and 2010 on Sharkey clay and Beulah fine sandy loam soil at Stoneville, MS, USA, under irrigated conditions. Soybean were grown in 102 cm single-rows and 25 cm twin-rows in 102 cm centers at SRs of 20, 30, 40, and 50 seeds m-2. The results showed that in May and June planting, protein, glucose, P, and B concentrations increased with increased SR, but at the highest SRs (40 and 50 seeds m-2), the concentrations remained constant or declined. Palmitic, stearic, and linoleic acid concentrations were the least responsive to SR increases. Early planting resulted in higher oil, oleic acid, sucrose, B, and P on both single and twin-rows. Late planting resulted in higher protein and linolenic acid, but lower oleic acid and oil concentrations. The changes in seed constituents could be due to changes in environmental factors (drought and temperature), and nutrient accumulation in seeds and leaves. The increase of stachyose sugar in 2010 may be due to a drier year and high temperature in 2010 compared to 2009; suggesting the possible role of stachyose as an environmental stress compound. Our research demonstrated that PD, SR, and RT altered some seed constituents, but the level of alteration in each year dependent on environmental factors such as drought and temperature. This information benefits growers and breeders for considering agronomic practices to select for soybean seed nutritional qualities under drought and high heat conditions.

Highlights

Soybean is a major oil and protein crop globally
Interactions of planting date (PD) × RT and Y × RT were significant for oil and oleic acid only, indicating that the response of oil and oleic acid to RT and PD were dependent on environmental factors in each year
RT was significant for raffinose, glucose, fructose, B and P, while seeding rate (SR) was significant for all minerals, and the sugars sucrose, raffinose, and glucose

Summary

Introduction

Soybean is a major oil and protein crop globally. The seed quality is determined by its composition, including protein, oil, fatty acids, sugars, and minerals. Soybean seed contains on a dry weight basis about 380 to 420 g kg−1 protein, 190 to 230 g kg−1 oil, and based on the total oil, 120 to 130 g kg−1 palmitic acid, 30 to 40 g kg−1 oleic acid, 480 to 580 g kg−1 linoleic acid, and 50 to 80 g kg−1 linolenic acid. They contain sugars such as monosaccharides (glucose and fructose), disaccharide (sucrose), and oligosaccharides (raffinose and stachyose). Seed composition constituents are genetically controlled; they are known to be influenced by biotic and abiotic factors such as genotype, maturity, growing season, geographic location, and agronomic practices (Harue and Hirokadzu, 1971; Chapman et al, 1976; Chy and Sheldon, 1979; Wilcox and Cavins, 1995)

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