Changes in Seed Quality during Maturation of Sunflower under High or Changeable Water Table Conditions

Growth, yield and quality of sunflower (Helianthus annuus L.) in a rotational paddy field were compared with those in an upland field. In the rotational paddy field the growth was significantly suppressed and the seed and oil yields were significantly lower than those in the upland field. In the maturing period, oil accumulated in seeds until about 25 d after flowering (DAF) in both fields, but less in the rotational paddy field than in the upland field. Differences in oil contents (per seed) between the fields were seen from about 25 DAF onward. The fatty acid in seeds changed with maturing of plants. In mid-oleic hybrids, oleic acid increased remarkably until about 25 DAF and then decreased slightly; linoleic acid content decreased until about 14 DAF and then tended to increase. In linoleic acid hybrids, oleic acid increased until about 14 DAF and then decreased; the linoleic acid content tended to be low until about 14 DAF and then increased. Although the temporal patterns of fatty acid compositions during seed maturation were similar in both fields, the oleic acid content tended to be lower in the rotational paddy field even under the same climatic conditions and ripening periods. The differences between the fields were seen clearly from around 25 DAF. We discuss our findings with regard to physiological changes in developing seeds and the effects of high or changeable soil moisture content on sunflower growth and quality.