Regional and Temporal Variation in Soybean Seed Protein and Oil across the United States

Abstract

Soybean [Glycine max (L.) Merr.] seed composition data are becoming critical for efficient marketing and trade of soybean and soybean products. Previous reports of variation in seed protein and oil across regions within the United States focused on variation associated with state and regional boundaries. We conducted an analysis of an 8‐yr survey of seed protein and oil across US states and regions, including a geostatistical approach to better characterize the continuous variation in seed composition on a regional scale. The objectives were (i) to determine the relative importance of temporal and regional variation, (ii) to explore the extent of spatial variability across years, (iii) to evaluate the temporal stability across regions, and (iv) to explore the negative correlation between protein and oil across regions and years. Our results confirmed previous findings showing higher protein concentration in southern states and regions. However, most of the observed variation occurred at scales below these political boundaries. The geostatistical approach indicated a moderate level of spatial dependency for protein and protein plus oil but low spatial autocorrelation for oil. In all cases, year‐to‐year variation in weather conditions modulated the expression of regional spatial patterns in composition. To fully predict seed composition at a regional scale would require additional information associated with weather and agronomic management.

Effect of seeding date, environment and cultivar on soybean seed yield, yield components, and seed quality in the Northern Great Plains

“…Rotundo, Miller‐Garvin, and Naeve (2016) identified a moderate regional dependency in soybean seed composition with a minimum range of about 300 km. Similarly, in a comprehensive review, Hu and Wiatrak (2012) concluded that the combined effects of planting date, photoperiod, temperature, and precipitation are primary factors influencing soybean seed yield and quality (Hu & Wiatrak, 2012).…”

Planting Date, Maturity, and Temperature Effects on Soybean Seed Yield and Composition

“…Helms and Orf (1998) showed that traditional breeding efforts could increase protein by 5 to 7%, but this simultaneously decreased yield by 70 to 110 kg ha -1 resulting in an overall decrease in protein ha -1 . The effect of the production location has possibly the greatest influence on seed yield, where soybean grown in the northern Corn Belt is consistently lower in protein compared to those grown in southern states (Rotundo et al, 2016). Hurburgh et al (1990) found that soybean from northern states contained 1.5 to 2% less protein and 0.2 to 0.5% more oil than soybean produced in the South and southeastern United States.…”

“…Significant spatial and temporal variability exists for protein and oil (Brumm and Hurburgh, 2006). Rotundo et al (2016) determined that the spatial variation occurs at scales lower than politically defined regional and state lines. Many underlying weather and environmental factors have been suggested to explain this variation, including differences in temperature throughout the growing season (Gibson and Mullen, 1996;Howell and Cartter, 1958;Thomas et al, 2003;Wilson, 2004;Wolf et al, 1982;Yaklich and Vinyard, 2004).…”

Amino Acid Balance is Affected by Protein Concentration in Soybean

“…There exists considerable variation in soybean protein concentration, based on a number of factors including genetics (Serretti et al, 1994;Zarkadas et al, 1999Zarkadas et al, , 2007 and environmental conditions (Rotundo et al, 2016), at the local, regional, and international levels (Thakur and Hurburgh, 2007;Karr-Lilienthal et al, 2004;Medic et al, 2014;Naeve, unpublished data, 2015). Studies like these, as well as soybean quality surveys, report changes in amino acids resulting from protein concentration differences across a number of locations, genotypes, and in some cases, years.…”