Breeding report of a new pear cultivar Shuduyu

Shuduyu is a new early- ripening pear (Pyrus pyrifolia) cultivar with attractive appearance, which was bred and selected by Sichuan Agricultural University. Its seedling was derived from a cross between Ninomiyahuri and Zaosu conducted in the experimental field in the 1990s. Field trials were conducted at three locations in Sichuan Province, namely Ya’an City, Chengdu City, and Guangyuan City. Shuduyu exhibits vigorous growth with semi-open branches. The one-year-old branches are yellow-brown on the sunny side, with medium internodal length and sharp-pointed dormant leaf buds. The elliptical leaves measure 10.36 cm in length and 6.45 cm in width, with green surfaces, pointed tips, and serrated edges. The fruit buds are elongated, and each cluster contains 5-8 flowers, which are characterized by overlapping, round petals. The economic characteristics of Shuduyu fruits include a spindleshaped form, yellow-green peel, and an average single fruit weight of 298.00 g. The fruit has a smooth surface, a waxy texture, and white, juicy flesh with a sweet-tart taste. Its texture ranges from fine to medium, with very few stone cells. Total soluble solids (TSS) content is 11.13%, and total acid (TA) content is 0.31%. Ascorbic acid content is 3.98 mg·100 g-1 , and total phenol content is 464.8 mg·kg-1 . The flesh firmness is 6.40 kg · cm-2 . Trees have strong growth vigor, low branching ability and a large number of short fruit branches. Shuduyu is self-infertile and requires pollination assistance. Under normal orchard management, it enters a stable production stage in the fifth year after planting. With a planting density of 3 m ×4 m, it produces approximately 1 718.7 kg per 666.7 m2 . Its phenological phases in Chengdu, Sichuan, include budburst in late February, peak flowering in mid-March that lasts about 8 days, fruit maturation in early July with a development period of approximately 111 days, and leaf shedding in mid-to-late November, resulting in a total growth period of 254 days. Shuduyu exhibits strong adaptability and resistance to adverse conditions based on multi-year and multi-location trials. It thrives in the hot, humid summers and cold winters of Sichuan The cultivar demonstrates robust cold resistance, with no observed frost damage to overwintering branches and flower buds. It also exhibits strong resistance to diseases and pests, with minimal occurrences of diseases such as pear black spot, pear scab, and pear rot, as well as pests like pear stem borer, pear psylla, and pear midge, under field conditions. Cultivation techniques focus on establishing high- standard orchards, allocating pollinating trees appropriately, conducting formative pruning, managing flowers and fruits, and preventing diseases and pests. Shuduyu is suitable for cultivation in the plain and hilly ecological regions for P. pyrifolia, particularly in Sichuan and Chongqing.