A new early ripening red table grape cultivar with muscat flavor ‘Ruidu Hongyu'

Abstract:‘Ruidu Hongyu'is an early ripening red table grape cultivar(Vitis vinifera) with muscat flavor.The original plant was selected from the bud mutation of‘Ruidu Xiangyu'in 2005 at the vineyard in Institute of Forestry and Pomology, Beijing Academy of Agricultural and Forestry Science(BAAFS).‘Ruiduxiangyu'is a green table grape cultivar selected from a cross between‘Jingxiu'and‘Xiangfei'. In2005, we found the fruit of a single shoot of the grafted vine was red; Besides, it ripened early and showed muscat flavor. We compared its characteristics with‘Ruidu Xiangyu'in detail. The results showed it was indeed a bud mutation. Then it was evaluated in regional trials under the name of‘26-11-4R'in the districts of Haidian, Pinggu and Daxing. After years of observation,‘26-11-4R'ripened early and had muscat flavor which showed great potential in the market. It was finally released as‘Ruiduhongyu'after the validation by the Committee of Beijing Cultivar Registration. The vigor of the vine is medium to strong.The shoot is half upright and the shoot tip is open with medium hair. The color of dorsal side of internodes is green with red strips, while the color of ventral side of internodes is green. The tendril is discontinuous,the length is medium. The mature leaf is heart shape, green, pentagonal, the size and thickness are medium. The blade margin is pronounced. The upper lobe has a little overlapped while the lower lobe is open.The teeth are convex on both sides. The petiole is shorter than the main vein. The petiole sinus is sagittal shaped. Average intensity of anthocyanin coloration of the veins on both sides of the leaf is extremelyweak. The cluster of‘Ruidu Hongyu'is conical with single or double shoulders. It has an average weightof 404.71 g, average length of 20.13 cm and average width of 12.27 cm. The length of rachis and peduncleis 5.14 cm and 0.83 cm, respectively. The cluster density is medium to loose. The berry is oval or long el-liptic shaped, 18.14 mm in diameter and 24.45 mm long, the average weight is 5.52 g with the maximumof 7 g. The berries are uniform in shape and color. The skin is crispy, with no or a little astringency. Thefirmness of the berry is medium. The flesh has a light to medium scent of muscat flavor. The flesh is juicy,crispy and colorless. The total soluble solids is 18.20%, the titratable acidity is 0.40%. In Beijing area,the time of budburst is usually at middle to late April, the flowering begins at late May, the fruit ripensand the shoot matures both at middle to late August. The average rate of bud burst is 83.16%, the rate offruiting shoot is 70.30% and the fructification coefficient is 1.70. The average yield is about 30 tonnes perhectare. In years, there was no severe winter injury or sprouting. It is resistant to fungal disease, but sensitive to downy mildew and anthracnose. When cultivated in Beijing, rain-shelter cultivation can reducefungal disease so that decrease pesticides consumption and increase the level of nutritional reserve. Flow-er thinning and cluster trimming is highly recommended, keep 70-90 berries per cluster is appropriate.Without rain-shelter facility, pay great attention to downy mildew and anthracnose. Avoid high productivi-ty if cultivated in greenhouse, otherwise the fruit size and flavor could be affected. One single trunk withhorizontal cordon trained system is recommended.