Breeding of a new early-ripening, yellow and bagging-free apple cultivar Yanxiangyu

Abstract: Yanxiangyu is a new early-maturing and yellow apple variety, formerly named HL-65. It is the seedling offspring of the Korean-introduced variety Honglu. Healthy seedlings were planted in the spring of 2005. After evaluation and screening, HL-65 was selected as an excellent single plant. Scions were collected in 2011 and grafted on Begonia octagona as rootstock. Young trees were planted in the apple variety selection garden of Yantai Academy of Agricultural Sciences in the spring of 2012 and be- gan to bear fruit in 2014. The variety has medium strong tree vigor, open canopy and spur type, is easy to initiate flowers and mainly bears short fruit spurs and axillary flower buds; the annual branches are reddish brown, with a small amount of villi, the average internode length is 2.1 cm, and the perennial branches are grayish brown; The mature leaves are oval, 8.7 cm long and 5 cm wide, and the petiole is 2.9 cm long. The leaf posture is inclined upward, the leaf tip is gradually pointed, and the leaf edge is serrated; The flower bud is light pink, the petals are round and pink white, and the diameter of corolla is 47.5 mm. In 2016, HL-65 entered the full fruit bearing stage. The fruit size of this variety is small, the average single fruit weight is 120.2 g, the fruit is long and cylindrical, the fruit surface is smooth, non-arris and waxy, and the fruit dots are medium large and medium dense. The variety has yellow peel, light yellow pulp, hard and crisp taste and sweet flavor, with soluble solid content of 14.3%, peeling hardness of 9.2 kg·cm-2, titratable acid content of 0.32% and vitamin C content of 2.53 mg·100 g-1. It was accepted by experts organized by Yantai Science and Technology Bureau in September 2016 and was named Yanxiangyu. Yanxiangyu is more resistant to storage than other early maturing varieties. It can be stored for 2 months under natural conditions. It matures in mid and late August. The fruit growth period is 115 days and the maturity degree is the same. Yanxiangyu is more resistant to ring rot, rot and  leaf blight than Gala and American No. 8. It is suitable for cultivation in Shandong province and apple planting areas with similar climate. Suitable rootstocks can be selected according to the thickness of soil layer in newly planted orchards, and the tree is suitable to adopt free spindle or high spindle systems. In addition to conventional chemical control, pest control should be combined with biological and physical control measures to achieve the purpose of producing high-quality and bagging-free fruits.