Temperature influence during seed filling on tocopherol concentration in a traditional sunflower hybrid

The effect of night temperature during short periods in seed filling on oil tocopherol content and tocopherol/linoleic acid ratio was investigated in a traditional sunflower hybrid. Seeds were sown in the field at Balcarce on the 3(rd) and 22(nd) of November. In each experiment, treatments in which night temperature was increased at three consecutive periods of 200 degrees C day (base temperature: 6 degrees C) were applied. Tocopherol concentration was reduced when night temperature was increased early in seed filling. Such an increase could be attributed to a correlative increase in the daily average temperature, as no differences in tocopherol concentration were found when plants were cultivated in growth chambers under different day/night temperature but at the same daily average temperature. Temperature affected tocopherol concentration mainly by affecting the oil weight per seed. The tocopherol/linoleic acid ratio was not affected by temperature.