Effects of streptomycin, gibberellic acid, and the synthetic cytokinin forchlorfenuron on the seed size of muscadine grape
Muscadine grape (Vitis rotundifolia Michx.) is native to southeastern USA. Although it has not been commercially cultivated in Japan, the unique taste of its berries makes muscadine grape potentially useful for expanding the table grape market in Japan.
To satisfy consumer demands, there has been an increase in the production of seedless Euvitis table grape (V. vinifera, V. labrusca, and V. labruscana) berries in Japan.
Moreover, seedless grape berries are generally produced by treating normally seeded cultivars (e.g., Delaware) with gibberellic acid (GA) and streptomycin (SM). Additionally, the synthetic cytokinin forchlorfenuron [N-(2-chloro-4-pyridyl)-N-phenylurea; CPPU] is often applied along with GA or SM to enhance berry set and the growth of seedless berries.
Although these chemicals have been used to produce seedless Euvitis grape berries, their effects on muscadine grapes remain relatively unknown.
The objective of this study was to clarify the effects of these chemicals on muscadine grape seed formation and development.
We used three hermaphrodite cultivars (Carlos, Bountiful, and Doreen) in this study.
In contrast to the well-known effects of GA on Euvitis seedless berry set, the GA treatments at 0 and 2 weeks before anthesis did not affect seed formation and development.
However, the SM treatment significantly decreased the seed weight, whereas the CPPU treatment increased the berry size.
We also observed that the SM treatment at 1 week before anthesis was more effective than the SM treatment at 2 weeks before anthesis for producing berries with small seeds.
Histological examinations of the female reproductive organs suggested that the SM treatment may have inhibited endosperm development, leading to the degeneration of the endosperm and embryo and the production of berries with shriveled seeds.
Osako, Y., Kaite, T., Yamane, H., Morimoto, T., Itai, A. and Tao, R. (2023). Effects of streptomycin, gibberellic acid, and the synthetic cytokinin forchlorfenuron on the seed size of muscadine grape. Acta Hortic. 1370, 163-170
DOI: 10.17660/ActaHortic.2023.1370.21
https://doi.org/10.17660/ActaHortic.2023.1370.21
DOI: 10.17660/ActaHortic.2023.1370.21
https://doi.org/10.17660/ActaHortic.2023.1370.21
CPPU, gibberellic acid, seedless, streptomycin, Vitis rotundifolia
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