Breeding report of a new short shoot bud sport apple cultivar‘Xinhong 5’

Xinhong 5 is a late maturing apple cultivar with good appearance. It is a new short branch type variety selected by bud mutation of Nagano Fuji No. 2 apple variety. In 2016, when the research team conducted a survey of Fuji apple mutant resources at Hongqi Po Farm in Aksu District, Xinjiang, they found that the fruit characteristics of the upper branches of one Nagano Fuji No. 2 plant were significantly different from those of other branches on the same plant. The fruit had a deep red surface, a high-pitched shape, and obvious short-branch characteristics. After verification, this mutant branch was identified as a natural mutation. It was designated as a superior variety that year. Subsequently, through multiple years of biological characteristic observations and fruit quality analyses at multiple sites, it was confirmed that the comprehensive traits of this variety were superior to Nagano Fuji No. 2, and the fruit quality was similar to that of the mother plant. Xinhong 5 is a compact tree with remarkable short branch characteristics. Its adult tree posture is semi open, and its crown is conical with good ventilation and light transmission; Perennial branches grayish brown, annual branches yellowish brown; Leaves oval, light green, slightly wrinkled; The flower buds are hypertrophic and adnate, and the flower buds are pink. The fruit is nearly round, the fruit type index is 0.88, and the average single fruit weight is 201 g. the pericarp is thick red, evenly colored, the bottom color is yellow, and the fruit surface is smooth, rust free and waxy. The flesh is yellow, crisp and sweet. The single fruit contains 5-8 seeds. The results showed that the soluble solid content was 16.32% , sugar acid ratio was 36.41, peeling hardness was 8.33 kg · cm-2 , vitamin C content was 2.16 mg · 100 g-1 , and the comprehensive quality was excellent. In Aksu region of Xinjiang (N 4°17'15", E 80°17'33"), the fruit growth period was 180-190 d, and it matured in the middle and late October. Usually, each inflorescence contains 5-6 flowers and 20 stamens per flower; The germination rate was 75.03%, and the branching ability was 10.36%. This variety has similar cold resistance to the common Fuji apples, is highly adaptable, but has relatively weak resistance to rot disease. It is resistant to storage, with a shelf life of 150d and can be stored for 5 months under cold storage. It is suitable to be planted in the main apple production areas, and it can blossom and bear fruit in the second to third year of grafting, with good yield. The yield of tall trees in the fourth year can reach 3000-3500 kg · 666.7 m- 2 . Deep soil layer with salt content＜0.3% should be selected pH＜8.5, Loam or sandy loam with organic matter＞1%. The planting row spacing is determined according to the root stock type, and the North-South row planting is adopted. Grass is planted between rows, and also configure short-stemmed varieties such as Golden Delicious and Red Delicious for cross pollination. Soil, fertilizer and water management shall be carried out in combination with flood irrigation or drip irrigation. Sufficient base fertilizer shall be applied in autumn, and nitrogen, phosphorus and potassium fertilizer shall be applied according to phenological stages in the growth period. The young trees should be light cut and long placed, and should be in the shape of a slender spindle. In the full fruit stage, they should be gradually adjusted to the shape of a free spindle, and pay attention to the renewal of branch groups to maintain the strong and healthy tree vigor.