A new table grape cultivar——'Ruiduzaohong'

Abstract: ‘Ruiduzaohong'is a purplish red,early to middle season table grape cultivar(Vitis vinifera) with good eating quality. The original plant was selected from a cross between‘Jingxiu'and‘Xiangfei'in 1998 at the vineyard in Institute of Forestry and Pomology,Beijing Academy of Agriculture and Forestry Science(BAAFS). The seedling was planted in 2001 and began to produce fruits in 2003. It was selected in 2005 for its large berry,good skin colour and crisp flesh. In 2006 it was grafted onto 5-year-old rootstock‘5BB'for trials and the cultivars‘Jingxiu'and‘Yatomi Rosa'were also included as controls.From 2009 it was evaluated in regional trials under the name of‘26-3-4'in the districts of Pinggu,Tongzhou,Daxing and Shunyi. It was finally released as‘Ruiduzaohong'after the validation by the Committee of Beijing Cultivar Registration.‘Ruiduzaohong'is a diploid V. vinifera. The vigour of the vine is medium. The shoot tip is half open with heavy hair,the shoot is half upright,distribution and intensity of anthocyanin coloration in shoot tip is heavy,density of prostrate hairs on tip is very sparse,erect hairs on tip is absent. The tendril is discontinuous and bifurcated,the color is near yellow-green. The bud is slightly pointed and slightly held out,anthocyanin coloration of buds is strong. The color of dorsal and ventral side of internodes is green with red strips. The upper surface of a young leaf is pea green(R.H.S. 61/2) color while the under surface of a young leaf is Spinach Green(R.H.S. 960/2) color. Average intensity of anthocyanin coloration of six distal leaves prior to flowering is weak. Density of erect hairs between veins at lower surface of 4th distal unfolded leaf is medium,density of prostrate hairs between veins at lower surface is sparse,erect hairs on veins at lower surface is absent,prostrate hairs on veins at lower surface is very sparse,average intensity of anthocyanin coloration of six distal leaves prior to flowering is weak. The shape of the mature leaves is pentagonal with undulate sides,medium thickness. The blade margin is pronounced in undulation. The petiole sinus is open and“V”shaped. The teeth are short with both convex and straight sides. Tooth at petiole sinus is absent and limited by veins. Upper lateral sinus is closed and shallow,lower lateral sinus is open and deep. Density of prostrate hairs between veins on lower surface of blades is very sparse,erect hairs between veins on lower surface of blade is sparse,prostrate hairs between main veins on lower surface of blade is very sparse,erect hairs on main veins on lower surface of blade is sparse,prostrate hairs on main veins on upper surface of blade is absent. The upper surface is green with rugose texture and glossy appearance. Anthocyanin coloration of main veins on lower leaf surface is extremely weak. The petiole is about 9.7 cm on average and shorter than the middle vein,prostrate and erect hairs on petiole are sparse. The flower is hermaphrodite and usually positioned at the fourth node. The cluster of‘Ruiduzaohong'is conical with single or double shoulders,has an average weight of 432.8 g,average length of 21.2 cm and average width of 13.1 cm. The cluster density is medium to tight. The length of peduncle is medium,approximately 4.5 cm. The berry is oval or elliptic shaped,27.2 mm in diameter and 24.0 mm long,the average weight is 6.9 g with the maximum of 13 g. The berries are uniform in shape and color,usually purplish red.The thickness of the skin is thin to medium. The firmness of the berry is medium,the flesh is juicy and crisp,and the average soluble solid content is 16.5%. Flavour is mostly neutral with some fresh scent. The number of seeds per berry is ranged from 2to 4. In the Beijing area,the time of budburst is usually middle April,and flowering at late May,the fruit ripens in early to middle August. The average rate of fruiting shoot is 48.43% and the yield is about 30 tonnes per hectare. Vertical trellis system and fan shaped pruning were recommended in the northern area. The vine has weak resistance to powder and downy mildew. A spray program suitable for disease control with most Vitis vinifera cultivars should be applied. Botrytis bunch rot and sour rots may cause losses if harvest is delayed,especially after rainfall. For commercial production,flower thinning and cluster trimming is highly recommended and potassium phosphate fertilizer should be supplemented after veraison.