Standard of high quality seedlings of jujube

⑴ special-grade seedlings: 1.2m to 1.4m in height, 1.5cm to 2cm in diameter, retaining permanent secondary branches more than 40cm from the ground, 30cm in length of thick roots with a diameter of 3mm, and the ratio of total length of fine roots less than 2mm in diameter to the weight of seedlings is more than 1.0mm. ⑵ first-class seedlings: the seedling height is 0.8m to 1.2m, the near-ground diameter is 0.8cm to 1.5cm, the secondary branches are more than 50cm from the ground, the length of the thick root with a diameter of 3mm is more than 20cm, and the ratio of the total length of the fine root less than 2mm in diameter to the weight of the seedling is more than 0.8. ⑶ secondary seedlings: the seedling height is less than 80cm, the near-ground diameter is 0.6cm to 0.8cm, and the thick root length of 2mm in diameter is more than 30cm.