Breeding of a new high-quality, large-fruit, mid-ripening and white-flesh loquat cultivar Zhongbai

Abstract: Zhongbai, a hybrid between Zaozhong 6 (♀, the female parent) and Guifei ( , the male parent), is a new high-quality loquat cultivar with big- fruit and mid- ripening period. Zaozhong 6 is well known for its orange-yellow flesh, extra early-ripening and big-fruit, while Guifei is white-flesh, lateripening and big-fruit. Zhongbai exhibits moderately strong tree vigor and a round-shaped crown with an obvious central leader and long and sturdy shoots. The panicle emergence stage of Zhongbai occurs from mid-October to late-November in Fuzhou, Fujian province. The initial flowering stage, the fullblooming stage and the late- blooming stage of Zhongbai are from late-November to early-December, from early- December to mid- December, and from late- December to early- January of the following year, respectively. The fruit of Zhongbai ripens from mid- to late-April. The ripening period of Zhongbai is 10 days later than that of its female parent Zaozhong 6, and about 7 days earlier than that of its male parent Guifei. Zhongbai has many characteristics, for example, the size of fruit is not uniform and the average weight of fruit is 60.1 g; the shape of fruit is obovate; the shape of most fruit base is obtuse, while a few is acuminate; the shape of most fruit apex is obtuse with slight concave. The color of pericarp is yellow with less rust spots; the pericarp has obvious fruit streak; the thickness of pericarp is moderately thin. The density of fruit dots is medium, and the size of fruit dot is medium large; the attitude ofsepals is flattened and the calyx cavity of fruit is closed. The color of flesh is yellow white and the average thickness of flesh is 10.9 mm. The average total soluble solids content is 13.4% and the taste of flesh is characterized by tenderness, absence of flesh dregs, rich flavor, juiciness and excellent quality. The average edible rate of fruit is 71.2% and the average number of seeds is 4.6. A small amount of flower could be found in the second year after top-grafting, and the flowering rate is about 50% in the third year after top-grafting. The high yield period of Zhongbai starts from the fourth year. According to the investigation, the yield of a single tree is about 22.8 kg, which is equivalent to 709.7 kg per 666.7 m2 . These results indicate that Zhongbai has the characteristics of early fruiting, as well as high and stable yield. Zhongbai has been applied in different areas and ecological environments across China for regional and productive experiments, and it also shows excellent characteristics in most of the prominent loquat production areas. In summary, Zhongbai is a new loquat cultivar with mid- ripening period, bigfruit, white flesh, high quality, high and stable yield, and strong resistance, and it is suitable to be applied in prominent loquat production areas, such as Fujian, Sichuan, Chongqing and Yunnan.