柳杉优树子代的遗传变异与再选择

Genetic Variation in Progeny of Chinese Cryptomeria Superior Tree and Reselection

根据31个柳杉优树无性系自由授粉子代测验林5龄时树高(H),胸径(D),材积(V),新梢长(N_g),树冠幅(C_d),侧枝数(N_b),结果数(C_n),结果率(C_r)和结果指数(I_c)估算的半同胞家系遗传力分别为0.566,0.509,0.462,0.679,-0.326,0.694,0.091,0.068和0.115.测算的遗传相关表明:H,D,V,N_g,N_b 5个生长性状之间,C_n,C_r,I_c 3个结果性状之间具强度正相关,这5个生长性状对C_r都是强度负相关,D,V对C_n和I_c具强正相关,H,N_g和N_b对C_n和I_c只具弱度相关。以选择强度i=1.4选出最好的6个家系,予测H,D,V,N_g,或N_b单性状选择的遗传增益分别为11.96％,21.25％,44.31％,22.42％和20.81％;按综合上述5个性状的选择指标进行多性状选择,遗传增益提高到28.64％.以全部性状表型值进行主成分分析,按各家系的主成分坐标值,易于直观地选择表型优良的家系,其选择结果近似于综合指标选择。

An analysis was conducted on the data from a 5-year-old progeny test plantation of 31 open pollination families of Chinese cryptomeria superior tree clones. The results showed that the heritability of tree height (H), diameter at breast high(D), volume(V), new growth of terminal shoot (Ng), crown diameter(Cd), new branch number on terminal shoot(Ab),cone number per tree (Cn), cone-bearing tree percentage (Cr) and cone-bearing index (Io) was 0.566, 0.509. 0.462, 0.679, -0.326, 0.694, 0.091, 0.068 and 0.115 respectively. The estimated genetic correlations among five growth traits: H, D, V, Ng, Nb, and among three cone-bearing traits: Cn, Cr, Jo, were all strong and positive. All of the growth traits were strongly and negatively correlated with Cr, the D and V also strongly and positively with Cn and Io, but the H, Ng, and Nb poorly with Cn and Io. The predicted genetic gains from single trait selection for H, D, V, Ng and Nb were 11.96%, 21.25% 44.31%, 22.44% and 20.81% respectively. The gain from multitrait index selection was 28.64% when the best 6 families were selected (at intensity i = 1.4). It was easily and visually to select the phenoty-pically superior families based on the principal component coordinate values of families; and the selected families were nearly the same as based on the index selection.