<正>以美国引进的北美悬铃木种源上海松江试验点5年生的试验林为材料，根据2004年底的试验结果，进行了优良家系及优良单株的选择。结果表明：在松江试验点，不同种源间和种源内的家系间存在明显遗传差异。根据表型选择的12个优良家系，其树高、胸径、材积方面分别比家系平均值高出6.5%、12.31%、28.54%；选出的16个优良单株。其树高、胸径、单株材积增幅分别为18.05%、38.79%、10.55%，其中这3个性状增幅最大的单株分别增加了44.07%、62.91%、224.92%。综合优良家系及优良单株的评选表明。适合松江点的材料多分布于美国中南部纬度偏北、经度偏东的地区。

A plantlet regeneration protocol was developed for Pinus thunbergii. The procedure involves 3 steps, axillary buds induction, buds growth and root induction. Axillary buds induction was found to be influenced by the concentration of 6-benzyladenine (6-BA) and alpha-naphthylacetic acid (NAA) in the induction medium as well as the age of the seedling from which the explant was taken. Of the various 6-BA and NAA combination tested, modified Gresshoff and Doy’s medium (GD) with 4 mg/L 6-13A and 0.05 mg/L NAA proved to be the most effective, and the right stage of seedling was 22 ~ 28 d. During the next 5 weeks of culture on the same 6-BA-free but with 0.1 mg/L NAA medium multiple shoots elongated from the buds. The medium containing GA3 did not support buds growth. Elongated shoots were transferred to half-strength WPM medium supplemented with 0.2 mg/L NAA for root initiation and 14 days later transferred to half-strength WPM medium without any hormone for root development. After 1 month, 23.3 ~ of the shoots had formed adventitious roots.