Abstract: [Objective] Through measuring and analyzing the shoot growth behavior and the content of N, P and K in needles of the young third generation of Masson pine(Pinus massoniana), this study revealed the mode of genetic control of shoot growth, explored the relationship between the contents of N, P, K and the growth, and provided a theoretical basis for understanding genetic laws of the height growth of Masson pine.[Method] We measured and analyzed the shoot growth behavior (initial shoot growth, subsequent shoot growth, annual shoot number and annual shoot length), tree height, and N, P and K contents in needles, to explore the genetic variation regularity and genetic control mode of shoot growth behavior and the needles nutrient content, and to reveal the genetic correlation between the shoot growth traits, and between the shoot growth traits and the needles N, P and K contents, with a half diallel cross among 6×6 Masson pine clones in Laoshan forest farm of Zhejiang Province.[Result] The value of initial shoot growth, subsequent shoot growth, annual shoot number, annual shoot length and average tree height were 0.89 m, 0.45 m, 1.90 times, 1.34 m and 5.16 m of trial plantations of the young third generation of Masson pine, respectively. The variance analysis showed that there were very significant differences between different hybrid combinations. The result of combining ability analysis showed that shoot growth behavior, such as, subsequent shoot growth, annual shoot number and annual shoot length, were given priority to additive gene effect control, with the percentage of additive gene effect from 52.10% to 73.28%, while the initial shoot growth was almost entirely controlled by dominant effect (98.32%). In the nutrient content of needles, K content was controlled mostly by additive gene effect (69.70%), while the contents of N and P were almost entirely controlled by dominant effect. Shoot growth traits, tree height, N, P and K contents were controlled by medium or above degree of genetic (h_f²=46.54%-84.17%). Through studying genetic correlation between the traits, it was found that there was very significant positive correlation between tree height and subsequent shoot growth, annual shoot length and shoot number. There was very significant positive correlation between subsequent shoot growth and annual shoot length and shoot number. There was very significant negative correlation between initial shoot growth and tree height, subsequent shoot growth and annual shoot number. There was no significant correlation between initial shoot growth and annual shoot length. There was very significant positive correlation between the N content in needles and tree height, subsequent shoot growth, annual shoot length and shoot number. There was very significant positive correlation between P content in needles and initial shoot growth and annual shoot length. There was very significant negative correlation between K content in needles and annual shoot length. There was significant positive correlation between N/P ratio and tree height, subsequent shoot growth and annual shoot number. There was very significant positive correlation between N/K ratio and tree height, subsequent shoot growth and annual shoot length; P/K ratio and annual shoot length.[Conclusion]The variation of shoot growth behavior and N, P and K contents in needles were rich in trial plantations of three generation of Masson pine. Subsequent shoot growth, annual shoot number and shoot length, tree height and K content were mostly controlled by additive gene effect. Initial shoot growth, N and P contents were almost entirely controlled by dominant effect. The height growth of trees was affected by shoot growth behavior, especially the subsequent growth was significantly affected by subsequent shoot growth features. The annual shoot length was increased, and therefore the tree height was increased in the year.

Key words: Pinus massoniana, shoot growth behavior, foliar nutrient content, GCA, SCA, genetic correlation