Seed development and seedling growth after reciprocal crossing between diploid and tetraploid Muscat grapes [Vitis].
1992
Okamoto G. | Hirano K. | Tanakamaru N. | Omori N.
1. To obtain new seedless cultivars with excellent fruit quality in the Muscat of Alexandria grape, we conducted reciprocal crossing between 2x and 4x cultivars of Muscat of Alexandria grape. 2. There was a greater number of berries set on the cluster of 4x x 2x crossing than was found on that of the 2x x 4x and the 2x x 2x. The number of seeds obtained, however, was least on the 4x x 2x clusters due to fewer seeds per berry and a higher rate of seedless berries. 3. About 67 % of the ovules in set berries on the 2x x 2x cluster were growing normally when observed 2 weeks after pollination. The rate of such ovules was less than 10 % and 47 % on the clusters of 4x x 2x and 2x x 4x, respectively, because the nucellus of their ovules had shrunk and degenerated. The cell division of an embryo proceeded in the ovules of 2x x 4x clusters as well as in those of 2x x 2x clusters. No embryo could grow to the heart-shaped stage in the 4x x 2x ovules. 4. Harvested seeds from those clusters were tested for their germinability and seedling growth after dormancy-breaking treatment. The rate of seeds which produced a potted seedling of the 2x x 4x progeny was one third that of the 2x x 2x. No progeny was obtained from the seeds of the 4x x 2x berries.
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