What are the main improved walnut varieties in China?

  1. Lüling

  Origin and distribution: A bud sport selected from Xiangling walnut by Hebei Agricultural University and Hebei Lüling Fruit Industry Co., Ltd. Selected in 1995, after multiple generations of grafting propagation, the traits are stable, intermediate testing in 2000, and in 2005 it was recognized and named by the Hebei Provincial Forest Tree Variety Approval Committee.

  Fruit economic traits: The nut is ovate, light yellow, with average horizontal, longitudinal and vertical diameters of 3.42 cm, single nut weight 12.8 g, shell thickness 0.8 mm, uniform without exposed kernel, suture line smooth and not protruding, shell surface smooth and attractive; inner seed coat light yellow, no astringency, kernel light yellow, plump and strongly aromatic, kernel rate above 67%; fat content 67%, protein content 22%. Compared with Xiangling, Lüling walnut has the advantages of thinner shell, larger nut, higher kernel rate, and higher fat and protein content.

  Growth and fruiting habits: The tree is vigorous, with an open tree posture. Female inflorescence has 1-2 flowers, male inflorescence 2-4 cm long. In Lincheng, Hebei, budbreak is in late March, leaf expansion in early to mid-April, fruit ripening in early September, 3-5 days later than Xiangling, fruit growth period 110-120 days, leaf fall in early November. During the full fruiting period, pay attention to using upper branches and upper buds to rejuvenate scaffold branches, and cut back and renew perennial fruiting mother branches and drooping branches. Apply base fertilizer in autumn, 50-80 kg organic fertilizer per tree, 0.5-1 kg diammonium phosphate or 1-2 kg special fruit tree fertilizer. Topdress before germination, during young fruit expansion and during the fruit hardening stage; for young trees, 0.1-0.3 kg urea per tree, 0.2-0.5 kg special fruit tree fertilizer. During the full fruiting period, apply 1-1.5 kg urea per tree and 2-2.5 kg special fruit tree fertilizer. Irrigate before germination, during the fruit hardening stage, and before winter freezing.

  2. Baokexiang

  Origin and distribution: A seedling tree selected by the Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences from seeds introduced from Xinjiang. During the "Seventh Five-Year Plan" period, it participated in the national regional trial of early-fruiting walnut varieties, and is being introduced and cultivated in various provinces of North China and Northwest China.

  Fruit economic traits: The nut is relatively large, average single nut weight 13.02 g, maximum 15.5 g, average of three diameters 3.58 cm, shell surface smooth and attractive, shell thickness 1.19 mm, suture line tight, whole kernel can be obtained, kernel rate 51%, kernel color light, flavor aromatic, quality superior.

  Growth and fruiting habits: The plant is vigorous, tree posture relatively upright, branch angle about 55°, crown round-headed. Leaves large and thick, dark green. It belongs to the protandrous type, a late-maturing variety. This variety has strong productivity, strong cold resistance, drought resistance and disease resistance, and has strict requirements for cultivation conditions. It is suitable for growing in arid loess hilly areas, and when cultivation conditions are good, its fruiting life is long.

  3. Zhonglin No. 1

  Origin and distribution: Bred by the Research Institute of Forestry, Chinese Academy of Forestry using Shanxi Fenyang Chuanzi (late-fruiting) as the female parent and Qixian Jian 9-7-3 (early-fruiting) as the male parent. Passed appraisal by the Ministry of Forestry in 1989. It belongs to the early-fruiting walnut variety type.

  Fruit economic traits: The nut is medium-sized, average single nut weight 10.45 g, maximum 13.1 g, average of three diameters 3.38 cm, shell surface relatively smooth and attractive, shell thickness 1.1 mm, suture line slightly protruding, tightly closed, whole kernel or 1/2 kernel can be obtained, kernel rate 57.4%, kernel color light, flavor aromatic, quality superior. In a ventilated, dry, cool place (below 8°C), it can be stored for one year without quality decline.

  Growth and fruiting habits: The plant is vigorous, tree posture relatively open, branch angle about 65°, crown naturally round-headed. Leaves thick, dark green, photosynthetic capacity relatively strong, it belongs to the protogynous type, a mid-maturing variety. This variety has strong continuous fruiting ability, and when it bears too much fruit the nuts tend to become smaller, so attention should be paid to strengthening fertilizer and water management. Relatively cold-resistant, drought-tolerant, but disease resistance relatively poor.

  4. Jinfeng

  Origin and distribution: Selected by the Shanxi Provincial Forestry Research Institute from Xinjiang walnut seedlings introduced in Qixian. During the "Seventh Five-Year Plan" period, it participated in the national regional trial of early-fruiting walnut varieties, and is mainly cultivated in Shanxi, Shaanxi, Henan and other places. It belongs to the early-fruiting walnut variety type.

  Fruit economic traits: The nut is medium-sized, ovate, average single nut weight 11.34 g, maximum 14.3 g, average of three diameters 3.47 cm, shell surface relatively smooth and attractive. Shell thickness 0.81 mm, suture line tight, whole kernel can be obtained, kernel rate 67.0%, kernel color light, flavor aromatic, quality superior. In a ventilated, dry, cool place (below 8°C), it can be stored for 10 months without quality decline.

  Growth and fruiting habits: The plant grows moderately, tree posture open, branch angle about 70°, crown semi-circular. Fruiting branches strong, leaves thick, dark green, glossy, it belongs to the protandrous type, an early-maturing variety. This variety is high-yielding and stable-yielding, with a relatively high fruit-setting rate and relatively weak apical dominance, so attention should be paid to thinning flowers and fruits, strengthening fertilizer and water management, reducing the proportion of small nuts, and extending the fruiting life. This variety is cold-resistant, drought-resistant and relatively disease-resistant. The female flowers open relatively late, which helps avoid late frost damage.