Breeding report of a new loquat variety Yongxi

Yongxi is a late-ripening loquat variety characterized by its crack resistance and low-temperature tolerance. The single plant originated from a seedling of the Xishangbaisha, a local variety from Zhejiang Province. In 2005, during an investigation on loquat germplasm resources, a research group discovered an exceptional individual plant with superior quality in Xishang Village, Huangyan, Zhejiang Province. Through years of continuous observation, high-grafting identification experiments, variety comparison experiments, and regional cultivation trials, this single plant demonstrated strong cold resistance, crack resistance, and stable genetic traits. It was officially authorized as a new plant cultivar by the Ministry of Agriculture and Rural Affairs on September 18, 2024, and was named Yongxi, with variety rights number CNA20211001290. Yongxi loquat is a semi- upright tree with a semicircular crown and vigorous growth. Its leaves are medium-sized, lanceolate, dark green, and covered with numerous hairs on the lower epidermis. The leaf blade margin is shallowly serrated, and the base is narrowly wedge- shaped. In central Zhejiang, Yongxi typically produces three shoots annually: spring shoots, summer shoots, and autumn shoots; in some years, late autumn shoots also occur. The flowering period extends from October to early February, with full bloom generally lasting from early November to early January. The inflorescence is conical, averaging 11.4 cm in length and 9.2 cm in width, with an average of 80 to 90 flowers and numerous stamens. The fruit matures in late May, approximately seven days later than its parent Xishangbaisha. The fruit has a nearly round shape, with an average weight of about 38.1 g per fruit. Its surface is orange-yellow, occasionally marked by rust spots. The flesh is yellow-white, tender, free of flesh dregs, juicy, and flavorful, contributing to its excellent quality. The soluble solids content is 14.1%, while the titratable acid content is 0.37%. Additionally, the vitamin C content measures 13.5 mg·g-1 , with an average of three seeds per fruit and an edible rate of 72.1%. Yongxi variety demonstrates frost resistance and is less prone to fruit cracking. Compared to the primary culti-var, Ruantiaobaisha, Yongxi shows significantly improved cold resistance. When it is exposed to temperatures below -3 ℃ for 48 hours, the embryo freezing rate of Yongxi remains below 30%, whereas that of Ruantiaobaisha exceeds 90% . Yongxi loquat can preserve its desirable traits through grafting, with a preference for common loquat as the rootstock. Trees typically begin bearing fruit in the second year after grafting, with a high yield period and a high commercial fruit rate starting in the fourth year. The recommended planting density is approximately 1110 plants per hectare, with a planting spacing of 3.0 m × 3.5 m. A leader-layered tree structure is advisable, with a height limit of 3 meters. Orchards should be established in flat or mountainous regions with an average annual temperature exceeding 15 ℃ and a minimum temperature not lower than -8 ℃, preferably in sandy soil. Suitable cultivation areas include Zhejiang Province, Jiangsu Province, and adjacent subtropical regions known for loquat production.