Breeding of a new mid-to-late ripening apple cultivar Wangyuebingcui

Wangyuebingcui is a mid-to-late season apple cultivar optimized for fresh consumption, and characterized by its premium yellowish- green exterior. This variety was developed through controlled hybridization in 2007 in the experimental orchards using Tsugaru as the maternal parent and composite pollens blend from Fuji and Danxia cultivars. Following germination of labeled hybrid seeds in the spring of 2008, 1256 robust seedlings were meticulously cultivated. The hybrid population commenced significant fruiting in 2013, with successive selection rounds in 2014 (primary) and 2015 (secondary) identifying superior traits including consistent productivity, balanced sweet-acid flavor profile, crisp-textured juicy flesh, spontaneous floral initiation, and distinctive unbagged green fruits with glossy surfaces. Multi- regional adaptability trials conducted in Linyi, Wanrong, and Pu counties of Yuncheng City demonstrated exceptional environmental adaptability, culminating in formal cultivar registration as Wangyuebingcui in 2024. The cultivar exhibits an open-branching architecture with primary branch angles exceeding 70°. Juvenile branches present reddish- brown coloration featuring sparse lenticels and moderate pubescence, maturing to grey-green in 2-3 year growth with brown, slightly protuberant lenticels. Foliar morphology includes lanceolate-elliptic laminae (mean 9.83 cm×5.0 cm) with acute apices and crenate margins, displaying slight undulation from pale green in juvenility to dark green in maturity. A cluster contains 5- 6 flowers with 4.37 cm diameter corollas on 2.21 cm pedicels, transitioningfrom pink buds to pinkish-white ovate petals. Fruit development progresses from greenish-brown at immature stage to subglobose at maturity stage (shape index 0.91) with uniform yellowish-green base coloration. The waxy and blemish-free surface encases creamy-white flesh exhibiting dense cellular structure, notable crispness, and abundant juice secretion. Average fruit mass reaches 194.70 g (maximum 222.97 g), containing 5- 7 seeds per fruit, with distinctive sweetness (15.60% soluble solids content) and pronounced aromatic quality. Physicochemical profiling confirms premium attributes: 0.22% titratable acidity, 2.48 mg · 100 g- 1 vitamin C content, and firmness of 8.32 kg · cm- ². The 135-140 day fruit development cycle culminates in mid-September maturation in central Shanxi (37°20′36″ N and 112°29′ 35″ E), demonstrating negligible preharvest drop. The cultivar combines high budbreak rate with moderate branching capacity, exhibiting spur-type growth pattern, sustained cluster-base productivity, and axillary flowering propensity. Notable resistance to anthracnose leaf spot (Glomerella cingulata) and broad environmental adaptability are documented. Postharvest evaluations reveal extended storage potential without pathological deterioration. It is adaptable to all major Chinese apple-growing regions, achieving second-year fruiting capacity and stabilized yields of 28.86 t · hm- 2 during full production. Rootstocks are recommended to apply Malus baccata or M. robusta as base stocks, and the SH series as interstocks, or alternatively employ self-rooted dwarfing rootstocks such as M9-T337 and G935. Planting densities should follow 2 m×4 m (standard) or (1.0-1.5) m×4 m (high-density) configurations, and trees should be trained to slender spindle system. Canopy management involves spring branch thinning for structural optimization and summer practices including branch training, shoot pinching, vegetative growth control, and light exposure maximization. Pollination systems require (7-8)∶1 ratios using Danxia, Fuji, or Gala cultivars. Nutrient management emphasizes autumn organic manure and phased nitrogen-phosphorus-potassium application at critical growth stages, supplemented by foliar calcium-magnesium fertilization during rapid fruit expansion.