Soybean Seed Composition as Affected by Seeding Rates and Row Spacing

Abstract

Research on the effects of seeding rates (SDR) and row spacing (RS) on soybean [Glycine max (L.) Merr.] seed composition is almost nonexistent. The objective of this research was to investigate the effect of SDR and RS on soybean seed protein, oil, fatty acids, sugars, and minerals using four soybean cultivars (P 93M90 and AG 3906, maturity group[MG] III; P 94B73, MG IV; and V 52N3, MG V) tested in 2006 and 2007. Seeding rates for P 93M90 and AG 3906 ranged from 247,000 to 592,800 seeds ha⁻1 and for P 94B73 and V 52N3 ranged from 60,000 to 180,000 seeds ha⁻1. Row spacings were 38 and 76 cm. Protein, oleic acid, sugars, P, and B concentrations increased with the increase of SDR in P 93M90 and AG 3906. However, after the maximum concentrations of these constituents were reached, a decrease was observed at the highest SDR. This trend was mainly observed in 2006 and depended on RS. In 2007, the opposite trend of protein and oleic acid concentrations was observed, where the protein and oleic decreased with SDR. In cultivars P 94B73 and V 52N3, results showed that protein concentration increased with SDR in 2006 and 2007 for both 38 and 76 cm RS. Oleic acid increased and linolenic acid decreased with SDR in 2006. The different trends of protein and oleic concentrations between years may be due to temperature and drought stress differences. This research showed that SDR and RS can alter seed constituents, and the magnitude of this effect depended on cultivar and environmental factors, especially temperature and drought.

Effects of Drought and Elevated Atmospheric Carbon Dioxide on Seed Nutrition and 15N and 13C Natural Abundance Isotopes in Soybean Under Controlled Environments

“…Mature seeds were ground using a Laboratory Mill 3600 (Perten, Springfield, IL, USA), and the ground samples were analyzed for minerals, N, S, and C, by digesting 0.6 g of the grounddried plant materials in HNO 3 in a microwave digestion system as detailed elsewhere [29,30]. Potassium was determined by inductively coupled plasma spectrometry [29,30].…”

“…Potassium was determined by inductively coupled plasma spectrometry [29,30]. Each content of N, C, and S was measured in a 0.25 g ground-dried sample which was combusted in atmospheric oxygen of 1350°C, and then the elements N, S, and C were converted to N 2 , SO 2 , and CO 2 , respectively.…”

“…Each content of N, C, and S was measured in a 0.25 g ground-dried sample which was combusted in atmospheric oxygen of 1350°C, and then the elements N, S, and C were converted to N 2 , SO 2 , and CO 2 , respectively. The contents of N, S, and C in seed were measured by an elemental analyzer using thermal conductivity cells (LECOCNS-2000 elemental analyzer, LECO Corporation, St. Joseph, MI, USA) [29,30].…”

“…The mature seed samples of 25 g were ground using the Laboratory Mill 3600, and seed protein, oil, and fatty acids in the samples were analyzed by near-infrared reflectance [29][30][31] using a diode array feed analyzer AD 7200 (Perten, Springfield, IL USA). The calibration equation was developed using Preteen's Thermo Galactic Grams PLS IQ software, and the calibration curve was established using Association Official Analytical Chemists (AOAC) methods.…”

“…The calibration equation was developed using Preteen's Thermo Galactic Grams PLS IQ software, and the calibration curve was established using Association Official Analytical Chemists (AOAC) methods. The contents of protein and oil were determined based on a seed dry matter [29,31]. The contents of palmitic, stearic, oleic, linoleic, and linolenic fatty acids were determined based on a total oil basis [29].…”