Breeding report of new late-ripening apple cultivar Liaoping

Abstract:  Liaoping is a new late-ripening apple cultivar with excellent appearance. The seedling was derived from a cross between Hanfu and Yueshuai in 1996 in the experimental field. It was initially se-lected in 2003 for its prominent colors and strong sweet and acid flavor. Through artificial hybridization pollination, 768 hybrid seedlings were planted in 1997. Liaoping was considered as a primary selection strain in 2008. The original code of Liaoping was 62-45. After regional adaptability testing at two sites (including Heishan country, Jinzhou city, and Dengta area, Liaoyang city,) over six years from 2015 to 2020, it was finally selected in 2019. This variety is tall, attaining a height of 3.5 m. The tree is vigorous with semicircular crown and upright gesture. 1-year-old branch is yellow-brown. The average length of branch is 35.3 cm. The average width of branch is 5.4 mm. Leaves are ovate to elliptic, and acuminate. The ratio of leaf length to width is 1.6. The average length of leafstalk is 3.7 cm. There are five flowers within each cluster. Petals are pink. The diameter of flower is 4.1 cm. Most bearings came from both ax-illary flower bud and spurs on young trees. The fruit is oblate and the top of fruit is slightly prism. The fruit is full range of dark red without bagging and it’s easy to set color. The ground color is yellowish-green. The average single fruit weight is 235 g. The fruit shape index is 0.85. The flesh is yellow and white. The flesh texture is light and crisp. The flavor is strong sweet acid and juicy. The soluble solid content is 13.9%, and total acidity is 0.51%. Fruit hardness is 10.8 kg · cm^-2. Quality is excellent. The fruit development period is 165 d, and it matures in mid-October in Xiongyue area with 122°09′ east longitude and 40°10′ north latitude. The branching ability is moderate medium with an average of 5.3. The self-pollination rate is low, only 2.65%. It’s high yield. Usually, an orchard should be established with vigorous large branching seedlings and 83 plants are planted per 666.7 m 2. It has moderate disease  resistance. The fruit is susceptible to water core disorder. The plant is moderate resistance to ring rot of apple. The fruit has very long storage-life, cold storage life is 7 months and shelf life are over 90 days. The fruit has better flavor after storage. This variety is suitable for cultivation in Heishan area, south of Jinzhou and similar climate areas in Liaoning province. Fruiting started at the second year after plant-ing. In the third year, the average yield was 6847.5 kg·hm^-2. In 7th year, the yield was 60 258 kg·hm^-2.On flat terrain, fertile soil with good irrigation conditions, dwarf trees and trellis cultivation can be ap-plied. On mountain or relatively barren soil, relatively adaptable trees should be chosen. Spacing in the rows and between rows are 2 m × 4 m on vigorous rootstock and 1.5 m × 4 m on dwarf rootstock. The suitable interstocks are Malus micromalus, M. hupehensis, GM256, Liaozhen 2, etc. The S genetypes was S1S9. Suitable pollination varieties can be chosen from Golden Delicious, Gala, Yueyan, Yueyang-hong, Yuehua, Yueguan, etc. Trees should be shaped as high spindle or thin spindle system, and the height is controlled at 3 to 3.5 meters. The number of branches is 30 to 35, angle of branch is from 100° to 120°, and the ratio of branch thickness to trunk thickness is from 1∶3 to 1∶5. Liaoping fruit is fully colored, which can be considered as non-bagging cultivation. In order to prevent from fruit water core disorder, 300 kg·hm^-2 of calcium nitrate can be applied into the soil in spring. Before fruit bagging and picking, amino acid calcium should be sprayed 2-3 times.