Temperature and cultivar effects on soybean seed oil and protein concentrations

Abstract

The soybean [Glycine max (L.) Merr.] industry is interested in cultivar and climate effects on seed composition. These factors may underlie the known geographic variation in seed protein and oil concentrations. Regression analyses were used to test hypotheses of the effect of temperature and cultivar on oil and protein concentrations of soybean seed using a large data set from the U.S.A. Soybean Uniform Tests. The data set included 20 cultivars representing 10 maturity groups across 60 locations (latitude 29.4 to 47.5°N) for a total of 1863 cultivar by location by year observations. Temperature was determined for each observation as the average daily mean temperature from predicted first pod (first pod at least 5 mm long), using the SOYGRO phenology model, to observed maturity. The mean temperature ranged from 14.6 to 28.7°C among the observations. Linear, quadratic, and linear plateau regression models of oil and protein concentrations vs. temperature were evaluated. The quadratic model gave the best-adjusted R 2 values for oil and protein with temperature, of 0.239 and 0.003, respectively. The analyses showed that the oil concentration increased with increasing temperature and approached a maximum at a mean temperature of 28°C. Unaccounted variation in the protein concentration may be from other factors such as photoperiod, water stress, or high temperatures during seed fill. Protein plus oil had a linear relationship with temperature (adjusted partial R 2 = 0.183). These data document the contribution of climate and cultivar to geographic variability of oil and protein concentrations in the United States.

Impacts of Heat Stress on Wheat: A Critical Review

“…Increasing temperatures from optimum 25°C to 28°C, the oil content increased however, above 28°C the oil content declined [94]. In case of soybean seed protein content remained constant at temperatures between 16°C and 25°C but increased at temperatures above 25°C [94,95]. During seed-filling stage the oil and protein concentrations were inversely related in response to heat stress [94].…”

“…In case of soybean seed protein content remained constant at temperatures between 16°C and 25°C but increased at temperatures above 25°C [94,95]. During seed-filling stage the oil and protein concentrations were inversely related in response to heat stress [94]. Pipolo et al [95] concluded similar quadratic response for oil and protein concentrations of soybean seeds cultured in vitro.…”

“…Seed composition and transcript abundance were also affected by heat stress [93]. Increasing temperatures from optimum 25°C to 28°C, the oil content increased however, above 28°C the oil content declined [94]. In case of soybean seed protein content remained constant at temperatures between 16°C and 25°C but increased at temperatures above 25°C [94,95].…”

Rising atmospheric carbon dioxide on grain quality in crop plants

“…Tomas et al (2003) studied the interactive effects of elevated temperature and CO 2 on soybean seed composition. As growth temperature of field-grown soybean increased up to a mean of 28°C, oil concentration increased and protein concentration decreased from 14°C to a minimum at 22°C (Piper and Boote 1999). In addition to changes in the concentration of oil produced in seeds, the ratio of fatty acids in soybean oil changes when seeds develop under elevated temperature.…”

Plant N Fluxes and Modulation by Nitrogen, Heat and Water Stresses: A Review Based on Comparison of Legumes and Non Legume Plants

“…In rice after heading, kernel N concentration increases when temperature is raised from day/night values of 27/22°C to 33/28°C but remains thereafter steady when temperature is subsequently increased up to 39/34°C (Tashiro & Wardlaw, 1991). Similarly, in soybean, in the range of temperature encountered by the plants during the reproductive period seed N concentration increases with temperature up to a day/night temperature of 40/30°C (Piper & Boote, 1999;Thomas et al, 2003). Several authors suggest that the earlier arrest of seed filling due to heat stress interferes with the accumulation and processing of the latest proteins accumulated.…”