ブドウ巨峰の着色に及ぼす光度の影響

Effects of lightintensity around ciuster from veraison to maturity on the coloration and pigmentation in 'Kyoho' grape were studied for 3years from 1980 to 1982.
1. Light intensity was reduced by covering clusters with different kinds of bags to 5 levels ; 75%，70%，30%，20% and O% of natural light intensity．Due to these treatments, fruit temperatures measured between 1 and 2 P.M. on fine days became 0.2～3.5℃ high, and such a trend was particularly obvious in 20% and 0% light treatments.
2. The anthocyanin content in berry skin in 'Kyoho' was 10 to 30% lower than that in 'Campbell Early', and less than 50% of that in 'Muscat Bailey A'. Although no color change occurred in any of the treatments in 'Muscat Bailey A', either 'Kyoho' or 'Campbell Earley' showed lower calor degree of clusters as decreasing light intensity. The anthocyanin content in 0% light treatment was 30.0% of that in non-bagged control in either cultivar, and the content in each treatment was almost parallel with light intensity.
3. The depressive effect of cluster shading on the pigmentation in 'Kyoho' was different depending on year, and the effct was stronger in the year in which air temperature was higher and insolation duration was larger during coloration.
4. The anthocyanin content in 'Kyoho' decreased as decreasing light intensity as early as a week after the beginning of treatments. Removal of bags l0 days before harvest time did not affect significantly the content in 70% light treatment.
5. The abscisic acid content in berry from veraison to maturity was not influenced by the shading treatments in 'Kyoho'.
6 . Twenty anthocyanins were separated from the skin pigment of 'Kyoho' by thinlayer chromatography and the most dominant one among them was estimated to be Malvidin monoglucoside. Any of the shading treatments did not affect remarkably the quantitative ratio of dominant 4 anthocyanins.