State Certificated Variety——Zhongyu 7 Sweet Orange

  The Zhongyu 7 Sweet Orange is a highly honored variety, achieving the National variety certification in 1997. “The Breeding and Application of the Zhongyu 7 Sweet Orange” was awarded the third prize of the state technological invention progress in 1999.

Zhongyu 7  The Zhongyu 7 Sweet Orange was selected from seeds of the Jincheng sweet orange treated by 60Co-γ at the CRIC, CAAS. The Jincheng sweet orange, a superior local sweet orange strain, has a beautiful egg-like fruit shape with a very smooth and brightly colored rind, but it is seedy. After irradiation treatment, seed-free and seed-few mutations were found and observed in the following breeding process. The Zhongyu 7 Sweet Orange was one of the top selections, which was seedless, but kept the superior characteristics of the Jincheng sweet orange.

  The fruit of the Zhongyu 7 Sweet Orange is seedless, with an average of only 0.06 seeds per fruit. Studies show that the main reason for seedlessness is the abnormality of the meiosis of pollen mother cells, induced by irradiation. The fruit is ellipsoid to a short oval in shape, with a bright and deep orange rind color, and a very thin peel. The average fruit weight is 170-180g, and the flesh is very tender and rich in fruit juice, with a 58% juice yield; the total soluble solids content is 12%. In 100ml of juice, there is 10.8g of invert sugar, 0.9g of citric acid, and 48-57 mg of vitamin C. Zhongyu 7

  The tree of the Zhongyu 7 Sweet Orange is robust with strong adaptability, and it is very productive, with a high yield stability. The average yield of a 6-8 year-old tree in 3 consecutive years is 14.6kg. In Chongqing, the fruit matures in late October or mid-November, about ten days earlier than the Jincheng sweet orange.