Breeding report of a new early-maturing plum cultivar Duanwuhong

Duanwuhong is a new early-season plum cultivar selected from a spontaneous a spontaneous seedling of the local Furong plum, discovered in June 2000 in a germplasm repository in Liancheng County, Fujian Province, China. The seedling was initially selected for its fruit maturing approximately 30-40 days earlier than the traditional Furong plum. A dual propagation system (top-grafting and seedling rootstocks) was employed from 2001, and multi-location trials across Fujian (2001—2006) confirmed its stable earliness, high quality, good yield, and broad adaptability, leading to its formal selection in 2006. Its name reflects mid-June maturity around the Dragon Boat Festival. The tree is a small, vigorous, deciduous tree with a semi-spreading canopy, reaching 3.5-4.5 m at maturity. Branch distribution is uniform. Annual shoots are green with a reddish tinge, maturing to pale grey-green. Bark on mature wood is grey-brown and smooth with small white lenticels. It has a high bud burst rate (about 85%) and strong branching capacity. Leaves are long-elliptic (6.57 cm × 2.33 cm) with an acuminate apex, cuneate base, and finely serrated margins; the blade is dark green above and lighter beneath, with a reddish-brown petiole. Floral buds are slender and sharply pointed. Flowers are perfect, borne in clusters of 1-3 before leaves, with five white petals, 20-30 stamens, and a delicate fragrance. The fruit is nearly round (shape index about 0.95) with an average weight of 35.0-40.0 g. The apex is slightly raised, the suture is distinct and asymmetric, and the stem cavity is of medium depth. The skin is a deep, uniform purple-red with a thick bloom and medium-dense russet dots. The flesh is vividly purple-red, fine-tex-tured, very juicy, low in fiber, and offers a balanced sweet-tart flavor. Soluble solids content averages 11.5%. The stone is small, cling, and weighs about 1.58 g, resulting in a high edible rate of 97.88%. Duanwuhong is precocious and highly productive, bearing fruit primarily on short fruiting branches and bouquet spurs. It is self-compatible with abundant flowering. A three-year-old tree yields an average of 11.8 kg per plant, increasing to about 38.5 kg for a six-year-old tree. At a standard density of 42 trees per mu, this equates to a potential yield of around 1617 kg per 666.7 m2 . In Fujian's main production areas, budbreak occurs in mid- February. Flowering begins in late February, with full bloom in early March, lasting 15-20 days alongside leaf emergence. Fruit stone hardens in mid-April, expands rapidly in early May, begins coloring in late May, and reaches full commercial maturity in mid-June. The total fruit development period is 90-110 days. The cultivar demonstrates strong field resistance to fruit cracking. Duanwuhong is well-adapted to the main plum-producing regions of Fujian, particularly the northwest and east. It can also be grown in central and southern Fujian at altitudes above 300 meters on welldrained, slightly acidic soils such as red or yellow earth. Key cultivation recommendations include: using peach (Prunus persica) rootstock; adopting an open-center training system with moderate spacing (e. g., 3.5 m × 4.0 m); applying pruning strategies that emphasize thinning over heading cuts; implementing fruit thinning due to high fruit set; tailoring fertilization to support early maturation (emphasis on basal organic fertilizer, controlled nitrogen and water post-color break); and employing integrated pest management against diseases like bacterial shot hole and pests such as plum fruit moth. Harvest should occur when the fruit attains full purple-red color, thick bloom, and optimal soluble solids content, typically around mid-June.