Abstract: Nantaihutezao is a new, extremely early-ripening grape variety selected on the mother fruit tree Summer Black by the method of nutritional line selection, which is a triploid European and Americas hybrid variety, and seedless. It was initially selected in 2011 for its bright colors and very early ripening time, which shows approximately 10 days earlier sprouting than Summer Black. After regional adaptability testing at three sites (including Changxing，Nanxun，and Jianshui) over three years from 2016 to 2018, it was finally selected in 2019.The tender shoots are semi-open, with medium dense hairs, and the tips are fully covered with anthocyanins. The young leaves are yellow-green with a red halo, and the upper surface is glossy, while the lower surface has medium density of creeping hairs. Mature leaves are green, nearly circular, with 3~5 lobes. Without the application of plant growth regulators, the fruit cluster is cylindrical and compact, with an average length of 20 cm, an average width of 5 cm, and an average cluster weight of 250 g. The berry is round, with an average single berry weight of 2.5-3 g, and a fruit shape index of 1.03. The peel is purple-black, thick, and astringent-free, with a smooth surface and thick bloom. The flesh is light purple, dense in texture, sweet in flavor, with a unique violet fragrance. After two treatments with plant growth regulators, the average cluster weight is 656.9 g, and the average single berry weight is 8 g. The flesh is juicy, with a soluble solid content of 17%-20%, a titratable acidity of 0.5~0.6%, the ratio of soluble solid to acid of 30, a hardness of 4.2-4.6 kg·cm-², a Vitamin C content of 6.36%, and an anthocyanin content of 4.9 mg·g-1 FW fresh weight in the peel. Quality is excellent. The fruit development period is 100 days. Under common rain-shelter cultivation conditions in Changxing, Zhejiang (longitude 119.97, latitude 31.04), the fruit matures at the end of June to early July. The average bud germination rate is 95.0%, and the branch formation rate is 90%. It has a strong capacity to resist saline-alkali and acidic soils, exhibits high resistance to powdery mildew, but has weaker resistance to gray mold compared to Summer Black.It is suitable for cultivation in the southern regions of China and the Honghe Valley area of Yunnan. It starts flowering and bearing fruit in the second year, with good yield performance, and an average yield of 1478.3 kg per 667 m². The suitable planting row spacing is 2.5-3.0 m, plant spacing is 2.0-2.5 m. Before the first flowering, trimming the flowers within 5-6 cm of the spike tip, and the amount of fruit is about 2200 clusters per 667m². Two treatments with plant growth regulators are required. In order to prevent bird damage, bag cultivation is suggested. 1-2 bud ultra short tip pruning is recommended for Winter pruning.
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