A new red-fleshed Actinidia arguta cultivar Ziyan

Native to China and known for its remarkable cold tolerance, many Actinidia arguta varieties are currently developed and have been predominantly cultivated in Northeast and Central China. While the Qinling-Bashan region of Shaanxi is exceptionally abundant in wild resources of Actinidia arguta, its development and utilization remain inadequate and further improvement in exploration and evaluation are needed, compared to Actinidia deliciosa. In 2003, the wild kiwifruit resource survey on the northern slopes of the Qinling Mountains in Shaanxi was conducted and a distinctive wild Actinidia arguta specimen was discovered. Characterized by red skin, red flesh, and relatively large fruits, it was named as Ziyan. Through grafting and systematic observations on botanical traits, fruit characteristics, and genetic evaluations, Ziyan demonstrated stable and distinct features: large fruit size, red skin and flesh, unique flavor, high yield, and strong stress resistance. After six years of regional trial evaluations from 2016 to 2022, the breeding process was accomplished, and the variety was registered in 2024. Ziyan is tetraploid female variety featured with cylindrical fruit shape and smooth surface, averaging 29.09 g in weight and having a fruit shape index of approximately 1.60. The skin, flesh, and core of the fruit all turn purplish-red when fruits are ripe. With a unique flavor, the fruit offers a perfect balance of sweet and sour taste for directly fresh consumption after harvest, and contains a soluble solids content of 15.01%, total sugars of 13.20%, total acids of 0.86%, vitamin C of 2040 mg kg-1 , and total anthocyanin content of 407.25 mg kg-1 . The fruit has a shelf life of over 3-5 days under ambient conditions and 30- 45 days when stored at 1.0 ± 0.5 ℃. In the Guanzhong area of Shaanxi Province, phenological develop-ment includes budbreak in mid-March, flowering in early May, and fruit maturation in late September, with a fruit growth period of 145- 150 days. The variety demonstrates vigorous growth with robust branching, showing a sprouting rate of 66.98% and branching rate of 66.27%. Fruit bearing primarily occurs on spurs. The variety displays strong resistance to drought, heat, and cold, while maintaining an extremely low incidence rate of canker disease and other plant pathogens. It is suitable for cultivation in northern Qinling foothills, southern areas of Shaanxi with high-altitude, and similar ecological regions, achieving average yields of 12.75 t· hm-2 during peak production periods. In practical production, it can be used as a distinctive kiwifruit variety for modern agricultural sightseeing and picking. Orchard establishment should be in the sites of well-drained and irrigated loamy soil with soil layer ＞1 m, pH 6.5- 7.5, and organic matter content ＞1%. Planting spacing should be 3 m × 4 m, using NDM07 as the pollinizer with female/male ratio of (6-8)∶1. Horizontal trellis system with“single main trunk and dual major vines”shape is recommended. Winter pruning focuses on minimal cutting, while summer pruning emphasizes shoot pinching. Flower/fruit management and fertilizer/water regulation should be strengthened, with fully decomposed cake fertilizer and farm manure as basal organic fertilizers, supplemented with phosphorus-potassium fertilizers and bio-bacterial fertilizers. The ground mulching should be applied in planting rows and inter- row cover cropping are proposed for improving orchard conditions. During growing season, scarab beetles and spotted lanternflies should be monitored, and bird prevention measures should be adopted before fruit maturation.