Abstract
The development of ovule and embryo sac was investigated in relation to double seed formation in peaches. Among 15 cultivars, ‘Juseito (red flower)’ showed the highest percentage of double seed formation at 75.1% on average for five years. ‘Hakuho’ had a relatively higher rate of 11.1%, while others including ‘Hakuto’ had less than 5.2%. Development of ovule and embryo sac, elongation of pollen tube in the pistils were determined among ‘Juseito (red)’, ‘Hakuho’ and ‘Hakuto’. In all cultivars, the pollen tube reached the micropile more than 7 days after pollination. By this time, most of the primary ovules were viable. However, the secondary ovules had aborted in ‘Hakuho’ and ‘Hakuto’ at a rate of 85.7% and 100.0%, respectively, while in ‘Juseito (red)’ only 18.2% of ovules had aborted. These findings suggest that the potentiality of double seed formation is determined before fertilization, and when the secondary ovules avoid abortion and persist until fertilizations, the possibility of double seed formation increases.
