Breeding report of Manshanhong, a new yellow-fleshed loquat cultivar with high quality and stress resistance

Manshanhong is a new high-quality loquat cultivar with medium maturing and yellow flesh, obtained from a cross between the female parent Ninghaibai and the male parent Jiefangzhong. Hybridization was carried out in December 2011, hybrid fruits were harvested in late May 2012, and seeds were collected and germinated in nutrient pots. In spring 2013, 450 hybrid seedlings were transplanted to the same base for field evaluation. The offspring of the hybrid began to blossom in 2016 and initiated fruiting in 2017. After 3 years of continuous analysis and evaluation, a superior genotype (temporarily numbered A207) was finally selected from the 450 hybrids, exhibiting delayed flowering, strong stress resistance, uniform fruit appearance, high fruit- setting rate, and superior fruit quality. From 2017 to 2019, three consecutive years of phenotypic evaluations confirmed the stability of its botanical and agronomic traits. It was provisionally named Zhehong 1, and in 2020, it was granted national plant variety rights under the official denomination Manshanhong. To validate its adaptability and commercial potential, 200 grafted seedlings were propagated in 2018 and introduced to demonstration orchards, including Yuhang District and Lanxi City, through a technology transfer agreement. These trial plantings began fruiting in 2022, with consistent trait performance observed over three consecutive years, confirming its stability across diverse environments. Manshanhong is a vigorous, semi- spherical, open- canopy tree with a distinct central leader. The trunk exhibits a grayish-white hue, sparse lenticels, and moderate pubescence. Mature one-year-old branches are brown, with an average length of 57.0 cm and a diameter of 1.4 cm for central branches, while lateral branches measure 44.5 cm in length and 1.3 cm in diameter. The tree produces five lateral branches per central branch on average, with medium branching capacity. Leaves on one-year-old spring shoots are dark green, thick, and rigid, with an elliptic in shape (32.9 cm × 12.1 cm, and length-to-width ratio 2.7). The leaf is slightly wrinkled, with a tapered apex, cuneate base, and flat margins. Leaf thickness averages 0.43 mm, with a concave cross- sectional profile. The adaxial surface is light green and pubescent, while the abaxial surface is gray-yellow with moderate pubescence and prominent reticulate venation. Leaf margins bear shallow, medium-density serrations covering half of the edge, with 16-18 pairs of lateral veins. Petioles are short (1.1 cm) and thick (5.5 mm), with deciduous stipules averaging 13.5 mm in length. Manshanhong flowers in late autumn to winter, with a delayed phenology: initial flowering occurs in early December, full bloom from late December to early January, and terminal flowering in late January to early February. Inflorescences are conical, averaging 9.5 cm in length and 10.5 cm in width, with eight horizontally spreading rachises per cluster. Each inflorescence bears approximately 106 flowers, characterized by yellow-white petals (26.6 mm in diameter), five pistils, and 22-24 stamens per flower. Fruits ripen around May 25 in Haining City, Zhejiang province, and a near-spherical shape with closed calyx cavities. Post-thinning fruits average 48.9 g in weight. The peel is orange-yellow, resilient, and easy to separate from the flesh. The orange- yellow pulp has medium firmness, tender texture, high juiciness, and excellent melts in the mouth. Biochemical analysis reveals soluble solids content (SSC) of 14.9%, titratable acidity (TA) content of 0.31%, and an edible rate of 75.8%. Each fruit contains 5.8 seeds on average. This variety exhibits strong resistance to fruit cracking and sunscald, coupled with excellent fruit quality. Under openfield cultivation, the average yield reaches 979.9 kg per 666.7 m2 for six-year-old trees. Manshanhong represents a significant advancement in yellow-fleshed loquat breeding, combined with delayed phenology, robust adaptability, and superior fruit traits, marking it apromising leading cultivar for commercial loquat production.