This experiment was performed to investigate the split aspect and the susceptibility to berry splitting in 6 cultivars known to differ in their resistance to splitting, and to study their histological characteristics of berry skin related to susceptibility to splitting. The results obtained were follows:
1. Varietal differences of split region in the berries were recognized. Most of splits broke out at the middle of their berries in Campbell Early, Seibel 9110, and Tanored; at the top in Muscat Bailey A; both their middle and top in Neo Muscat and Kyoho.
2. Top and contact regions were higher in firmness than base portion.
3. Critical turgor pressure, which resulted in 50% splitting of the berries, was 23.3 and 20.6 atm in Neo Muscat and Seibel 9110 respectively, relatively higher among cultivars tested, while those of Tanored and Campbell Early were low with respective 6.5 and 8.9 atm.
4. Minimum soluble solids that occurred critical turgor pressure required for berry splitting, were 5.6% in Campbell Early, 13.5% in Seibel 9110, 12.0% in Kyoho, 14.8% in Neo Muscat, 3.9% in Tanored, 9.4% in Muscat Bailey A, respectively.
5. As compared with the characteristics of berry skin between Neo Muscat, resistant to splitting, and Tanored, prone to splitting, the cuticular and subepidermal layers were thicker in Neo Muscat thanin Tanored.
6. Subepidermal layers in berry skin of compact bunches were thinner in comparision with those of loose bunches in Tanored grapes.
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