Effect of water stress on grape fruit growth under delayed cultivation

Objective To provide a basis for the precise control of grape,Vitis vinifera,fruit development under delayed cultivation.

Method A main local grape cultivar Red Globe was planted in local ordinary sunlight greenhouse.Grape growth was divided into different stages including budding,grapevine extension,flowering,berry expansion,grape coloring and maturing stages.There were mild and moderate water stress at each growth stage,with control of sufficient water supply during the whole growth period.The effects of different treatments on the expansion rates of fruit longitudinal and transverse diameter were studied,and the correlation between fruit growth and leaf nitrogen content or chlorophyll content under different treatments was analyzed.

Result and conclusion  There were two distinct peak expansion periods of grape fruit enlargement and the enlargement rate in the first peak was far higher than that in the second one.The enlargement rate of fruit longitudinal and transverse diameter respectively in the early 24 days and early 16 days of berry expansion stage determined the final fruit size.The moderate water stress from the late grapevine extension to the early berry expansion stage followed with sufficient water supply resulted in distinct water compensation effects on fruit expansion rate during the early expansion stage and the rate reduced again in the mid and late berry expansion stages.Leaf nitrogen and chlorophyll contents had significantly positive effects on initial grape fruit enlargement rate from the late grapevine extension stage to the early berry expansion stage.