Correlation between temperature and oleic acid seed content in three segregating soybean populations
The development of high-oleate soybean [Glycine max (L.) Merr.] germplasm, currently in demand due to its nutritional value and oxidative stability, may be hampered by the instability of fatty acid composition across environments, which is largely attributed to temperature changes and its effects on fatty acid biosynthesis during the period of oil deposition. In the present study, we evaluated three soybean populations that segregated for oleate content and maturity at multiple environments in North Carolina. Oleate content was positively correlated with daily temperatures, averaged over the seed-filling stage, for the experimental lines of the late-maturing population but was negatively correlated for the lines of the early-maturing populations. Oil content was positively correlated with the average daily temperature during seed filling in all three populations, regardless of their early- or late-maturity profile. Negative correlations between oleate content and temperature during the period of oil deposition have not been previously reported. Moreover, in contrast to previous reports, maximum, minimum, and average daily temperatures were highly correlated during seed filling in all environments of this study. We conclude that cautious interpretation of these findings is necessary due to the correlation between temperature and photoperiod during the period of oil deposition.