Studies on the floral bud differentiation of grapes grown in greenhouse

The studies on flower bud differentiation of grapes in the greenhouse were conducted by observing the differentiation of flower bud at the whole growth period of 2-year-old to 4-year-old vines of Kyoho and Centennial Seedless cultivars. The results showed that: the proportion of differentiation was lower, the degree of primordial differentiation of second branch was not fully developed, and the flower bud was not formed completely under the condition of raising the temperature at the earlier time for both cultivars. The flower bud formation was related to the nutrient status of the vines. At the beginning of the differentiation the phosphorus dropped significantly, and content of proteins tended to drop and increase after primordial differentiation of second branch. The content of phosphorus increased remarkably. The differentiation of flower bud was related to the leaf's age after renewed. The inflorescence primordial started to emerge while the leaf age was 15 d, and leaf age at 27 d was the beginning of primordial differentiation, of second branch and the full stage observed on the 46th day of leaf age. The average proportion of differentiation was 91.1%. The flower bud formation of Kyoho and Centennial Seedless cultivars grown in greenhouse needs the renewal of the shoots. It's important to improve the management of shoots after renewed to get a stable production.