Long Leaf Sweet Orange

Long Leaf Sweet Orange

　　Long Leaf Sweet Orange

　　Breeding Institutions: Citrus Research Institute, Chinese Academy of Agricultural Sciences; Yinfeng Horticultural Farm, Jiangjin District, Chongqing

　　Variety Source: Selected from a superior bud mutation of the common Long Leaf Orange

　　Characteristics: The tree is vigorous with a naturally round crown. Branches have short thorns. Spring shoots bear narrow, lanceolate leaves, measuring 10.2 cm in length and 3.6 cm in width, with a leaf index of 2.8. Flowers are white, with an upright style, pale yellow anthers, and strong pollen viability. The fruit is spherical, weighing about 170 grams per piece, with a transverse diameter of 6.7–7.4 cm and a longitudinal diameter of 6.3–7.3 cm; the fruit shape index ranges from 0.93 to 0.98. The peel is relatively smooth with sparse oil glands. The fruit apex is flat with an indistinct ring mark, the stylar region has radial grooves, and the base is flat. The peel is tightly adhered, making peeling moderately difficult; it is 0.35–0.40 cm thick and consists of 10–11 segments. Upon maturity, the central core is well-developed, the flesh is orange-yellow, the juice sacs are slender, and the segment walls are thin. The flesh is tender, easy to separate, seedless or with few seeds, and often multi-embryonic. The fruit matures in late December and stores well. It can be kept on the tree for freshness, extending the harvest period to mid-to-late March of the following year.

　　Key Quality Indicators: Soluble solids content: 12.8–13.4%; reducing sugar: 11.12–12.26 g/100 ml; invert sugar: 5.83–6.22 g/100 ml; titratable acid: 0.78–1.0 g/100 ml; solid-acid ratio: 13–17:1; vitamin C content: 43.83–54.83 mg/100 ml; edible rate: 66.2–73.5%; juice yield: 51.0–60.6%. Suitable for both fresh consumption and processing.

　　Yield Performance: When grafted onto trifoliate orange rootstock, the tree generally regains vigor and begins to flower and bear fruit in the second year, reaching a yield of about 40 kg per tree by the fourth year, and over 60 kg per tree at peak production. Grafted seedlings on trifoliate orange rootstock begin flowering in the third year after planting, yield an average of 15 kg per tree in the fourth year, and 35.5 kg per tree by the sixth year.

　　Suitable Regions and Cultivation Key Points: 1. Suitable for promotion in sweet orange-similar ecological production areas, particularly as a dual-purpose (fresh and processing) variety in the Three Gorges Reservoir Region. 2. In production, trifoliate orange, trifoliate orange hybrid, and Ziyang Sweet Orange can be selected as rootstocks, but in alkaline purple soil regions, Ziyang Sweet Orange is recommended. 3. Plant at a spacing of 3 m × 5 m, with 44 trees per mu. 4. The tree is vigorous, and long on-tree storage of fruits requires greater water and nutrient supply. Heavy application of base fertilizer is necessary, primarily using well-rotted farmyard manure and compound fertilizer. In purple soil or infertile sloping land, improve soil fertility by adding more organic matter and balancing nitrogen, phosphorus, and potassium fertilizers. During shoot growth periods, supplement chelated iron, zinc, and magnesium fertilizers as needed to prevent deficiency symptoms. 5. The fruit matures in late December and stores well. It can also be kept on the tree for freshness until mid-to-late March of the following year. To avoid alternate bearing, harvest fruits timely based on tree load, completing the harvest by the end of March.