毛红椿生长、心材和材性性状遗传分析及家系选择

[目的]通过研究15年生毛红椿家系试验林的生长、心材和材性性状的遗传变异规律,选择速生且优质的毛红椿优良家系。[方法]以浙江开化县林场的15年生毛红椿家系试验林为材料,测定其树高、胸径、材积、心材率、心材材积和木材基本密度,进行方差、相关和主成分等分析。[结果]毛红椿家系间树高、胸径、材积、心材率、心材材积和木材基本密度等6个生长、心材和材性性状的差异均达极显著水平,并有较高的遗传稳定性,但冠幅和枝下高在家系间差异不显著。表型相关和遗传相关分析表明,毛红椿胸径与心材材积和材积之间呈显著正相关,通过对胸径的选择能间接实现对材积和心材材积的选择。主成分分析结果显示,材积、心材材积、胸径、树高和心材率等5个性状代表了毛红椿的品质和经济性状,对前两个主成分PC1和PC2的贡献率较高。通过构建材积、心材率、心材材积和木材基本密度等4个性状的综合指数选择方程,对毛红椿所有家系进行综合评价,选出了2个符合改良条件的优良家系,其材积、心材率、心材材积和木材基本密度获得的平均遗传增益分别为:52.84%、0.49%、66.23%和2.13%。[结论]毛红椿育种目标应重点围绕生长和心材性状,而冠幅和枝下高遗传力较小且家系间差异不显著,不适宜作为遗传改良的目标。

Magnetoelectroelastic fields in rotating multiferroic composite cylindrical structures

An analytical solution is obtained for a rotating multiferroic composite hollow cylinder made of radially polarized piezoelectric and piezomagnetic materials. Both the number of layers and the stacking sequence of the composite cylinder can be arbitrary. General mechanical, electric and magnetic boundary conditions can be applied at both the inner and outer cylindrical surfaces. The state space method is employed so that only a 2×2 matrix is involved in the whole solving procedure. In the nu-merical experiments, the distributions of elastic, electric as well as magnetic fields in an internally pressurized rotating BaTiO3/CoFe2O4 composite hollow cylinder subjected to different boundary conditions are presented graphically. The results clearly show that the stress fields in a multiferroic composite cylinder are controllable.