Anew Chinese bayberry cultivar Dingkui

Dingkui is a new Chinese bayberry variety selected from a single variant found in the growing orchard of Ding'ao. After more than 20 years of observation and identification on the mother tree and offsprings, it is believed that the characteristics of the variety are stable and consistent. When the fruit fully matures, the flesh column is round and blunt, the average fruit weight is 22.6 g, the fruit hardness is 2.89 N, the fruit shape index is 0.97, the solid soluble content is 10.8%, the titratable acid content is 10.57 g·kg-1, the total sugar content is 73.3 mg·g-1, the flavone content is 0.74 mg·g-1, the polyphenol contentis 1.77 mg·g-1, the amino acid content is 7.76 mg·100 g-1, and the vitamin C contentis 33.3 mg·100 g-1. The tree is strong in vigour and round or semicircular in shape, and the trunk and branches are short. The leaves are lanceolate-inverted, dark-green, 11.1 cm long and 2.7 cm wide, and have a short petiole. The flower is pure pistil, the female flower inflorescence is cylindrical, 0.76 cm long and 0.31 cm thick, and the flower is “V”-shaped. The budbreak period of Dingkui flower buds is in late February, the initial flowering period is in early March, the peak flowering period is in early March, and the final flowering period and young fruit period are in mid-March. The fruit ripening period is in early June, and the fruit development period is 55-60 days. The top flower buds on short fruit branches in spring and summer mainly bear fruits, with a natural fruit setting rate of about 15%, significantly lower than that of Ding'ao. The artificial thinning amount during fruit setting is small and it is easy to manage. Generally, it enters the peak production period 5-7 years after high grafting, with an average yield of 660 kg·666.7 m-2. We used SNP molecular marker technology to conduct molecular identification on 18 Chinese bayberry samples collected in 2023. The clustering analysis results confirmed that Dingkui did not have any homonyms with other varieties. 18 materials were divided into 2 groups, with Dingkui located in Group Ⅰ and showing differences from the other 17 materials. Among them, Dingkui and Ding'ao had the closest genetic relationship with a coefficient of 0.92, indicating that Dingkui is a new germplasm. It is suitable for cultivation in the south of Yangtze River and areas with similar climate, especially in southern Zhejiang. We suggest choosing gravelly red and yellow soil with deep depth, sufficient moisture, and pH between 4.5-6.5 for orchard establishment, and adopting natural sod system for orchard soil management. The recommended spacing for cultivation is 5 m × 5 m or 5 m × 6 m, with 20-30 plants per acre. For dwarfing and dense planting, a spacing of 4 m × 4 m can be used, with 42 plants per acre and planting holes of 0.8 m × 0.8 m × 0.6 m. There is no special requirement for the configuration mode for male plants in the orchard, which is the same as that of Ding'ao. In production, some bare branches should be pressed and hung, and thin and weak branches, overlapping branches, crossed branches and dead branches with diseases and pests should be cut off. In the fruiting period, fertilizer should be applied three times in spring, summer and autumn every year, about 1-2 kg of pure potassium sulfate should be applied to each plant for each time, and the ratio of nitrogen, phosphorus and potassium for adult trees is 1∶0.3∶4. Strengthen routine cultivation management, maintain reasonable ventilation and light transmission for tree crown, and pay attention to clearing the orchard in winter. There are few diseases and insect pests.