This experiment was conducted to study the response of ethephon on maturation and to examine the possible effectiveness of calcium to prevent ethephon-induced abscission of ´Campbell Early´ grape berries.
l. Ethephon at 1.000 ppm, applied to grapevincs at 20 days before veraison decreased the contents of total acid, total sugars and total soluble solids but increased total phenols and leucoanthocy. anins.
2. Ethephon at 250, 5000, and 1,000 ppm applied at 10 days before veraison induced 2, 10, and 54% of berry abscission, respectively and decreased berry weight and inhibited anthocyanin and total sugar accumulation. However, these effects were offsetted with addition of 0.05 M calcium acetate to ethephon.
3. When ethcphon applied at rate of 500 and 1, 000 ppm at 10 days before veraison of grapes, berries in a cluster were trot evenly colored. However, when ethephon was applied with calcium acetate, the fruits were normally ripened with delaying mataration for 4 days compared with the control.
4. The rate of ethylene evolution from grape berry was more stimulated by addition of calcium acetate to ethephon compared with ethephon treatmnet alone.
5. These results suggest that ethephon application with calcium acetate be a good practice to regulate the maturation of grape fruits without affecting berry setting and fruit quality adversely.
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