湖南排牙山杉木优树子代测定长期试验的遗传分析

Genetic analysis of long-term progeny testing for Chinese fir plus trees from Paiyashan in Hunan

【目的】通过杉木优树子代测定的长期试验,阐明生长和材性性状的遗传变异、遗传控制程度和年年遗传相关,以及性状间遗传相关的年龄趋势,评价参试家系的生长表现,为杉木早期选择、间接选择和配合力育种提供理论依据。【方法】以1982年营建在福建省洋口国有林场的湖南排牙山种子园37株优树自由授粉子代测定林为对象,以林龄2~5 a和9~10 a树高,3~6 a、8~10 a、33 a和36 a胸径,以及36 a弹性模量为目标性状,利用基于最佳线性无偏预测并整合空间效应的混合线性模型方法,分析性状的遗传变异、单株狭义遗传力和性状间的遗传相关。【结果】树高、胸径和弹性模量性状在家系间均存在极显著的差异,林龄36 a时,径生长最优家系F7比最小家系F26和对照F38分别高29.7%和9.7%,弹性模型最高家系F14比最低家系F19和对照F38分别高29.0%和12.3%;性状的加性遗传变异系数介于4.4%~9.6%之间,胸径性状总体呈现先减小后增加再减小的趋势,树高性状呈现总体减小的趋势;胸径的加性遗传方差、空间自相关误差方差、随机误差方差第10年比第3年分别增加了357%、117%和309%,树高增加了294%、518%和337%,胸径第36年比第3年增加了563%、229%和993%;树高和胸径的单株狭义遗传力估计值分别介于0.18~0.30和0.10~0.21之间,且总体呈下降的趋势,说明树高和胸径性状受中等偏弱的遗传控制;生长性状的年年加性遗传相关极强,估计值均高于0.73,且随着林分年龄的增加有缓慢减小的趋势;胸径与树高间的加性遗传相关极强,估计值均高于0.97,且与弹性模量的加性遗传相关估计值为-0.038。【结论】湖南排牙山杉木优树自由授粉优良家系能作为高世代遗传改良的材料,树高和胸径性状之间可以进行有效的间接选择和早期选择,以缩短育种周期和提高育种效率。

【Objective】To clarify genetic variation,genetic control degree,trait-trait genetic correlations and their age trends,and ageage genetic correlations for growth and wood traits of Chinese fir(Cunninghamia lanceolate(Lamb.)Hook)plus trees,evaluate the growth performance of tested families,provide theoretical basis for early selection,indirect selection and combining ability breeding.【Method】37 plus tree open-pollinated families from the Paiyashan seed orchard in Hunan province were included,the progeny trial was established in 1982 in Yangkou state forest farm,Fujian province.Tree height from 2 to 5 and 9 to 10 year of stand age,diameter at breast height(DBH)from 3 to 6 year,8 to 10 year,33 and 36 years,and modulus of elasticity(MoE)36 year were the target traits.The mixed linear model method based on the best linear unbiased prediction(BLUP),integrated spatial effects,was used to analyze the genetic variation,the narrow-sense heritability,and the genetic correlation.【Result】Tree height,DBH and MoE show significant differences among families.At the stand age of 36,diameter growth of the best family F7 is 29.7%and 9.7%higher than the lowest family F26 and the control F38,respectively,and MoE of the strongest family F14 is 29.0%and 12.3%higher than the softest family F19 and control F38,respectively.The additive genetic variation coefficient is between 4.4%and 9.6%,DBH shows a decreasingincreasing-decreasing trend,and tree height an overall decreasing trend.Compared to the 3rd stand age,the additive genetic variance,spatial autocorrelation variance and random error variance of DBH are increased by 357%,117%,and 309%,and the tree height increased by 294%,518%and 337%at the 10th stand age;DBH increased by 563%,229%and 993%at the 36th stand age respectively;The estimates of individual tree narrow-sense heritabilities for tree height and DBH rang from 0.18 to 0.30 and 0.10 to 0.21,respectively,and show a downward trend.The estimates of age-age additive genetic correlations for growth traits are all higher than 0.73,and has a slow decreasing trend with the increase of stand age;The additive genetic correlation coefficients between DBH and tree height are all higher than 0.97,and the estimation with MoE is-0.038.【Conclusion】Excellent open-pollinated families of plus trees from Paiyashan can be used as infusion materials of advanced-generation genetic improvement for Chinese fir,and effective indirect and early selection can be carried out between tree height and DBH to shorten the breeding cycle and improve breeding efficiency.