Breeding report of a new disease-resistant walnut cultivar Long Wuren No. 1 …

Abstract: Long Wuren No. 1 is a new variety selected from the seedling population of Longnan Wuren walnut (Juglans regia‘Longnan Wuren’) in 2009 for its grey brown seed coat color, high yield, thin shell, robust tree vigor, and strong disease resistance. In 2013, scions were collected and grafted at the walnut genetic resources nursery of Longnan for field trial. In December 2023, it was granted the Plant Variety Rights by the National Forestry and Grassland Administration and named as Long Wuren No. 1. The variety exhibited high yield, disease resistance, and exceptional flavor. The tree posture was semiopen tree, and the crown was natural semi-circular. The mixed buds were round, the male flower buds were bare and cylindrical. The fruit was spherical and yellow- green in color, with sparse spots and a smooth surface. The fruit shape was round, the weight of the fruit was 13.4 g, the weight of the nucleolus was 6.8 g, the shell thickness was 1.35 mm, and the kernel yield was 50.8%. The fruit shell was smooth. The suture is flat and tightly union. The kernel was full, grey brown with oily flavor and no astringency. The content of fat was 65.8%, the content of unsaturated fatty acid was 91.04%, the content of protein was 20.6%. The quality was excellent. The buds bursted in middle March, the full blooming of the male flowers was in late March, the female flowers in early April, the fruits matured in early September, and the leaves fell in late November in Wudu, Gansu Province. Long Wuren No. 1 showed resistance to Xanthomonas arboricola and Colletotrichum gloeosporioides. The average yield in the fourth and fifth years after grafting was 1 531.2 kg·hm^-2 and 2 468.4 kg·hm^-2 respectively. Long Wuren No. 1 could be cultivated in plain land, hilly terrain, and terrace weir areas.