柳杉无性系的遗传和选择

根据浙江省90株柳杉初选优树在两个地点优树收集区按随机排列嫁接的每源株20～30个分株的表现,测定了嫁接后1,3和7年的树高、7年的胸径、3年开花株的比率、7年开雌花量以及成熟球果的果径和果高。方差分析(不含3年开花率)表明,无性系间差异均达极显著。平均生长优于一般林分,说明表型选择有效,但无性系间仍差异很大,最好无性系为最差无性系的1.76～2.64倍。广义遗传力估值由1年高的极低值(0.087)随年龄逐增,至7年达中等大小(0.422),开雌花量的遗传力值中等(0.377),球果径和高的遗传力略高(0.520和0.538),1,3,7年树高间紧密相关,但与源株15龄树高不相关,7年胸径与源株15龄胸径也无相关。生长性状与开花结果性状相关不紧密。在测验的优树群体中再选择10个最好无性系,在生长量上能进一步提高13％～26％.考虑到早晚期的性状相关和遗传力的变化,提早在5～7龄时实施早期无性系轮回选择,可能是柳杉改良最佳的策略。

Inheritance and Selection of Chinese Cryptomeria Clone

Ninety canditate plustrees of Chinese cryptomeria selected from Zhejiang had been grafted with a randomized design of single-tree plots in two clone banks. After grafting, the measurements of 1, 3 and 7 years'tree height, 7 years' DBH, 3 years' flowering plant ratio, 7 years' female strobi-lus number, mature cone diameter and cone height were made on 20-30 ramets of each ortet. The ANOVA for all traits (excluding the flowering ratio) showed significant difference among clones at high level. In comparision with the commercial plantations the average growth rate of these tested plantations was more higher and indicated the effectiveness of phenotypic selection. However, the clones differed in wide range and the best clone was 1.76-2.64 times over the worst. The estimated broadsense heritabilities(H2) for tree heights started from very low value (0.087) of 1 year height and increased with age up to moderate value (0.422) of 7 years' height. The H2 for female strobilus number was moderate (0.377), and H2 for cone diameter and cone height were slightly higher (0.520 and 0.538). The correlation coefficients among 1, 3 and 7 years' height were significant, but all of them as well as the 7 years' DBH didn't correlated with 15 years' height and DBH of their ortets. There wasn't a close relation between growth traits and blossoming and bearing cones. The selection of best 10 clones from the tested clone plantation would increase 13 per cent to 26 per cent in tree increment. The early reccurent selection at 5-7 year-old stage for Chinese cryptomeria breeding program could be a efficient improvement strategy, taking the change of heritability and the phenotypical correlation between early stage and later stage into account.