Breeding report of a new superior early-maturing apricot cultivar Zhongxing No. 8

Zhongxing No. 8 is a new early-maturing apricot cultivar selected from the crossing between 1-10 apricot and Sungold apricot. 1-10 apricot was obtained in 2005 by crossbreeding of Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, selected as the primary selection of superior cultivar in 2010, and widely cultivated in the suitable area of apricot in Henan Province. Sungold is a very early- maturing European sweet apricot cultivar introduced from the United States by Shandong Fruit Research Institute, and is widely cultivated in the suitable planting areas of apricot in China. Compared with the male parent Sungold, the fruit of Zhongxing No. 8 apricot has big size, smooth surface, bright color, thick and fine flesh, and rich aroma. This cultivar has excellent quality, very early ripening fruit, less physiological fruit drop, high and stable yield, strong adaptability and resistance. Zhongxing No. 8 apricot was approved by the Approval Committee for Improved Varieties of Forest Tree of Henan Province in December, 2023. The fruit is oval- shaped, with an average mass of 108.7 g and a maximum mass of 131.5 g. The average longitudinal diameter, transverse diameter and side diameter of the single fruit are 6.1 cm, 5.7 cm and 5.9 cm, respectively. The fruit has flat apex with a pointed tip, featuring nearly symmetry, deep suture line, and medium deep stem cavity. The fruit sur-face is smooth, the medium thick fruit peel is hairy. The fruit peel is orange with bright red on the sunny side when mature. The fruit flesh is orange in color, and delicate in texture with low fiber content, sweet and rich flavor, balanced sugar/acid ratio and intense fruity aroma. The fruit soluble solid content is 14.5%, the soluble sugar content is 9.0%, the total acid content is 1.2%, and the Vitamin C content is 7.9 mg · 100 g- 1 . The fruit stone is round, brown and detached from the flesh. The average fresh stone mass is 3.4 g, with the stone length of 2.8 cm, and the stone width of 2.5 cm. The kernels are plump and the average mass of the kernel is 0.6 g, and the edible rate is 96.6 %. In Lankao area, Henan Province, the flower buds of Zhongxing No. 8 apricot start sprouting in early March, blossoming in mid-March, and reaching its peak flowering period in the mid-late March, with a flowering period of 7 to 10 days. The flower is showy, and has five light pink petals with one pistil and 26-35 stamens. The anther is light yellow with a lot of pollen. The leaf buds burst in late March and the leaves expand in early April. Tree defoliation starts in early-November, and all the leaves have fallen by mid-November. The vegetative growth period of the tree is about 220 days. The fruit ripens in late May, and the fruit development period is approximately 60 days. The tree posture is spreading and the tree vigor is strong. The flower bud formation is easy and the fruits are mainly borne on the short fruit branches. The pollination tree is needed for its poor self-fruiting ability. The tree is highly and stably productive and starts to bear fruits in the second year after planting, and enters the high yield period in the fourth year. It exhibits strong adaption to undesirable circumstances, and is resistance to frost. It would be suitable for cultivation in Henan Province and other similar apricot-growing areas in China.