Breeding report of a new table grape cultivar Guipu No. 15

Abstract: Guipu No. 15 is a new red table grape cultivar (Vitis vinifera) with strong muscat flavor, which was bred from the cross between Shine Muscat (♀) and Ruidu Hongmei ( ) in 2018. More than 1200 hybrid seeds were obtained by artificial pollination in July 2018. They were planted in nutrition cups in a greenhouse in November 2018 and then transplanted in the grape plot in May, 2019, and the seedlings were normally watered and pruned. The hybrid progeny first flowered and bore berries in 2020. We found the berries of a single vine, which was named as 2018Y*HM-80, were bigger than other vines, and had strong muscat flavor and well differentiated flower buds. Owing to its high quality and great potential in the market, 2018Y*HM-80 was grafted on 5BB rootstock for further regional trials in July, 2020. Through 3 years of continuous observation on the growth and fruiting habits of grafted seedlings, 2018Y*HM- 80 vine showed stable economic characteristics and high- yield performance with good berry quality, and it was released as Guipu No. 15 with the registration code of GPD grape (2023) 450030 after the validation by the Ministry of Agriculture and Rural Affairs of the People’s Republic of China in 2023. Guipu No. 15 belongs to the hybrid between V. vinifera and V. labrusca. The tree vigor is moderate. The tip of the young cane is half-open with dense vertical villi, and the mature cane is yellowish-brown. The color of dorsal side of internodes is red, while the color of ventral side of internodes is green with red strips. Young leaf is reddish brown and has dense white fluff. The mature leaf is of medium size, heart shape, green and pentagonal. The lower surface of leaf is covered by dense white fluff. The upper lobe is deep and closed, while the lower lobe is shallow. The inflorescence of Guipu No. 15 is conical and moderate tightness without shoulder. The shape of berry is oval with red peel, the peel is moderate and covered with thin fruit powder, the flesh quality is fine and firm, and there are 1-2 seedsin each berry. Guipu No. 15 is suitable for two-crop-a-year cultivation in the subtropical areas. In Nanning, Guangxi, the first season fruit ripens in late June. The average weight of each inflorescence is 620 g with the maximum of 1044 g. The average weight of each berry is 11.6 g with the maximum of 16.5 g, the total soluble solids is 19.5% and the titratable acidity is 0.32%. The second season fruit ripens in late December. The average weight of each inflorescence is 480 g, the average weight of each berry is 9.78 g with the maximum of 14.23 g, the total soluble solids content is 18.5% and the titratable acidity is 0.68%. It is suitable for rain shelter cultivation in Nanning, Guangxi and other similar areas.