Genetic variability in the response of fatty acid composition to minimum night temperature during grain filling in sunflower

Abstract

It is not known if the response of the oil fatty acid composition to temperature is similar among sunflower hybrids, especially among traditional hybrids. The objective of this work was to asses the genetic variability of the response of the oil fatty acid composition to temperature during the period 100–300 °C day after flowering among sunflower hybrids. Seven traditional hybrids and a high oleic hybrid were grown in several locations of Argentina. With the same hybrids two experiments were carried out in growth chambers where the plants were exposed to different day–night temperatures during grain filling. From these field and growth chamber experiments wide ranges of variation of temperature and oil fatty acid compositions for each hybrid were obtained. The concentration of oleic acid in sunflower oil showed a sigmoidal response to minimum night temperature from 100 to 300 °C day after flowering, increasing almost lineally within a given range of temperature. Outside this range, the concentration of this fatty acid remained merely constant. The same mathematical expressions characterized the response of oleic acid concentration to temperature in both, traditional and high oleic hybrids. The same expression also described the response of other fatty acids to temperature in all the hybrids. Differences between hybrids were observed for the minimum and maximum concentration of oleic acid and also for the maximum slope and range of the response. Since the sum of oleic + linoleic acids increased with temperature, increasing temperature reduced the concentration of saturated fatty acids and behenic acid. Genetic variability in the response of these fatty acids to temperature was observed. The results presented here show that it is possible to obtain sunflower oils of very different qualities combining the genetic variability in the response of the fatty acid composition to temperature and the climatic diversity under which sunflower is cultivated.