A Study On The Delayed Harvest Cultivation In ’Yinhong’ Grape

In Zhejiang province, the maturity of grape is mainly in the middle of July to the end of August. So many grapes flowed to the market bring a lot of pressure to grape management and sales, hence forcing and delaying culture of grape were important. ’Yinhong’(V.vinifera×V.labrusca) cultivar had many excellent characteristics, such as strong resistance, high branching rate and extensive management. And it is one of the most promising popularized variety after’Kyoho’and’Fujiminori’in Zhejiang Province. The maturation of this cultivar was mainly in the middle of August to the end that is a good cultivar used to delay harvest cultivation.In our research,3-4a’YinHong’ grape was used to study the delaying effects on berry maturity and quality formation of tree shading, fruit shading and fruit load. The experimental designs are three aspects. ①Treatment of four different tree shading rate:0(contrast),30%,50% and 90%; ②Treatment of three different fruit bags to fruit bagging:The normal paper bag(light transmittance 53.24%), black polypropylene fruit bag(light transmittance 2.04%) and yellow-black compound fruit bag(light transmittance 6.74%). ③Treatment of three level fruit loads:2 kg/m2(1250 kg/667 m2),3 kg/m2 (1875 kg/667 m2) and 4 kg/m2 (2500 kg/667 m2). The detail results are as follows:1. All of tree shading can delay fruit harvest.30% shading rate can delay almost 35d,50% and 90% shading rate can delay 49d. Fruit dehiscent was increased gradually as shading levels increased, however, the leaves sunburned and the total soluble solids reduced as shading levels increased. The titration acid was no significant influenced with tree shading. The anthocyanin was the maximum at the 50% shading level. Quality of fruit and flower bud of 90% shading rate decreased significantly in the next year. The budding rate and panicle length reduced 6.13% and 5.51% respectively. The shading rate of 30% and 50% almost has no significance on fruit quality,50% shading level also can increase fruit weight and anthocyanin;2. Fruit bagging used black polypropylene and yellow-black compound bags could effectively delay fruit maturity to 20days. While, fruit quality of black polypropylene bagging was the worst because of high temperature and low light transmittance. Yellow-black compound bagging could improve fruit skin lightness, increasing the content of organic acid, however the contents of reducing sugar and anthocyanin were lower than the white paper bagging. Removing the bag before harvested 7 days had a good anthocyanin conten;3. Fruit load of 3 kg/m2 and 4 kg/m2 can delay fruit maturity for 14d and 42d, respectively. There was no significant difference for fruit weight among the treatments. However fruit quality of 4 kg/m2 is bad, such as soft fruit, low content of TSS and anthocyanin. After maturity, the flavor quality of fruit decrease quickly with delaying picking. Meanwhile, the flower quality is poor in the next year. The fruit weight, hardness and anthocyanin content in 3 kg/m2 load level are also lower than 2 kg/m2.In summary, three methods (tree shading, fruit bagging and load level) all can delay the harvest of grape, but they have different influence on maturity and quality of fruit. Shading rate below 50%, bagging with yellow-black compound fruit bag and fruit load level under 4 kg/m2 are feasible as methods for delaying harvest cultivation in’Yinhong’ grape. So we can choose one according to what we needed.