Breeding report of a new blueberry cultivar Sky Blue

The Sky Blue blueberry (Vaccinium uliginosum L.) is a new variety bred from a crossing between the Legacy and Cara’s Choice made in 2010 in the blueberry germplasm resource bank of Dalian Senmao Modern Agriculture Co., Ltd., located in Xinshi Village, Huajia Street, Jinzhou District, Dalian. The seeds were sown and 216 seedlings were obtained in 2011, Subsequently, in the spring of 2012, these seedlings were transplanted to Dalian Pushi Blue Agricultural Technology Co., Ltd., situated in Shuangsheng Village, Changling Town, Zhuanghe City, Liaoning Province. The hybrid trees started fruiting in 2015 and a superior individual was selected and recorded as 2019- 045.The berries were large, large in size and flattened and round in shape, covered with a thick and uniform bloom. The color was light blue. The fruit had a small and dry calyx scar, high firmness, sweet flavor, and aromatic scent. It was highly suitable for fresh markets. Between 2018 and 2019, continuous monitoring was conducted on the fruit quality, plant growth characteristics, and flowering and fruiting traits of this elite lineage and its asexually propagated descendants. The results indicated that the various traits of this cultivar exhibited good stability and consistency. In April 25, 2024, this cultivar received a new variety authoriza-tion certificate from the National Forestry and Grassland Administration and was named Sky Blue, with variety certificate number 20240014. The fruit clusters had a moderate density The average individual fruit size was 1.84 cm×1.47 cm, and the maximum fruit weight was 3.69 g and an average individual fruit weight was 2.77 g. The soluble solid content (Brix%) was 15%, with moderate acidity. Under natural growth conditions, fruits typically reached maturity by early July, categorized as mid-season variety. Sky Blue was an excellent cultivar of northern highbush blueberries characterized by an open tree structure and vigorous growth. The leaves were elongated oval- shaped with a deep green color and entire margins. The average leaf area was approximately 6.8 cm², with a leaf shape index of 2.28. The average length of new fruiting branches reached up to 14 cm, with each branch capable of producing approximately 12 fruits. The inflorescences of this cultivar were relatively short, with moderate anthocyanin coloration intensity in both flower buds and corollas. The corolla exhibited a saucer shape with distinct ribbed features. This cultivar was well suitable for northern regions of the Yangtze River or areas with high altitudes; it should be cultivated in fertile soil with good drainage properties to maintain adequate moisture without waterlogging. The ideal soil types were loam or sandy loam, with pH values 4.0 to 5.5 and organic matter content over 3.0%. Furthermore, the chilling requirement of the varity was 600 to 1200 hours.