Climatic influence on 7S and 11S subunit concentrations in soybean seed protein

Predictable seed protein quality might be an essential characteristic of new cultivars in soybean. This study was conducted to investigate how seed storage protein subunits are affected by climatic factors and to determine how genotypes differ in the responses. Four lines selected for seed protein concentration were studied at five locations of North Carolina. A linear regression were used to investigate climatic responses of 7S (α’, α, and β) and 11S concentrations. The highest 7S concentration environment had the smallest variance of average minimum daily temperature (VMnDT), while the lowest 7S concentration environment had the largest VMnDT, indicating that larger variation in minimum daily temperature may more decrease 7S concentration as a major influence during seed maturity. Seed storage protein concentrations appeared to differ among lines. NC106 and NC111 had relatively lower 7S and higher 11S concentrations, while NC103 and NC107 had relatively higher 7S and lower 11S concentrations. NC103 and NC106 appeared to differ in 7S concentration due to a difference in a α subunit concentration, while NC 107 and NC111 seemed to differ in 7S concentration due to differences in α’ and α subunit concentrations. However, a β subunit concentration showed no difference among all the lines. Lines tended to show different direction and degree of response to climatic variables. For 7S and 11S concentrations, opposite direction of response was found between NC103 and NC111 and the same one was observed between NC106 and NC107. Between 7S concentration and its fraction ( α’, α, and β), partially opposite direction of response was observed in NC103, NC106, and NC107. These may indicate differences in biochemical basis of genetic regulation for the storage protein concentrations.