Breeding report of a new valencia orange cultivar ‘Guixiacheng No. 1'

Abstract：‘Guixiacheng No.1'is a new valencia orange cultivar which was selected from bud mutation of‘Algerian Valencia Orange'for its big fruit size, high-quality and excellent appearance. The variation maternal plant was discovered in an orchard of‘Algerian Valencia Orange'which was planted in 1999 in Tiekeng village, Dajing town, Lingchuan county. This variety has a spheroid tree. The tree is strong vigorous. For a 9-year-old tree on poncirus trifoliate rootstock, the average height is 320.0 cm; average trunk girth is 29.8 cm and average crown size is 353.3 cm × 325.1 cm. Leaves on spring shoots is oval and apex mucronate. Leaf length is 8.75-14.21 cm, leaf width is 4.24-7.31 cm. and leaf index is 1.68-2.26. The flower is big, white and complete flower. Flower petals length is 18.9-24.8 mm, flower petals width is 5.7-8.9 mm, stamen number is 19-22. The fruit is mainly round or oval with orange peel and rough surface. The fruit top is round and the flesh is orange yellowish with sweet-sour flavor and aroma.The fruit weight is 197.8-259.7 g; fruit horizontal diameter is 71.0-80.3 mm, fruit longitudinal diameter is 68.6-80.1 mm; fruit shape index is 0.94-1.03; the number of seeds is 1-3. The fruit edible rate is70.28%-76.47%; Juice rate is 44.99%-54.39%; Per 100 m L of fruit juice, containing vitamin C is 45.96-55.04 mg; titratable acid is 0.68-1.20 g; total sugar is 7.18-9.65 g; the content of total soluble solid is10.2%-13.3%; the soluble solids to acidity ratio is 9.92-15.07. The fruit development period is about320-380 days. And its maturity period is from the late March to the late May in Lingchuan county of Guilin. The new cultivar has high yield potential. The yield could reach 60 000 kg per hm2. The suitable cultivation regions of‘Guixiacheng No.1'are in the south of Guilin in Guangxi where are suitable for the planting of Valencia orange. Orchards should be built in acidic soils which has ability of moisture and fertilizer retention. Virus-free seedlings should be planted. The best field planting density is 667 to1 111 per hm² in planting spacing 3 × (3-5) m. Main stem is 0.4-0.5 m high with 2-3 main branches, and the trees should be trained in natural roundhead shape. Young trees are inclined to sprout axillary flower buds;the excess axillary flower buds should be removed to avoid looting nutrients. For adult trees, 2, 4-D liquid at a concentration of 30-50 mg·kg-1 should be sprayed on tree for 2 or 3 times from the middle of November. It could effectively reduce fruit drop. After harvest, a certain amount of organic fertilizer should be given. Prevention of disease and insects should be taken seriously, especially Huanglongbing control.