Abstract
Development prediction models using meteorological data were created to examine the maturation characteristics of the tetraploid seedless grape ‘Azumashizuku’. °Brix at the full harvest time was estimated using a multiple regression equation with high-level significance. The predictors of the multiple regression equation were the accumulated actual sunlight duration in the maturation stage and yield. A significant correlation was found between the tartaric acid content at full harvest and the average temperature 3 to 17 days after the start of coloring. The day the sugar/acid ratio would reach 35 was predicted by the nonparametric DVR method using solar radiation; the predictive accuracy is high. It showed that solar radiation had an important impact on the maturation of ‘Azumashizuku’ after the beginning of coloration.
