4年生火炬松半同胞家系生长和分枝性状遗传评估

Genetic evaluation on growth and branching traits of 4-year-old half-sib families of loblolly pine

【目的】准确地对火炬松子代测定林进行遗传评估,以提高育种选择效率和遗传增益,并为育种群体和繁殖群体确定入选材料。【方法】以火炬松53个半同胞家系的1800多个单株为研究对象,应用R和ASReml软件对树高、胸径和材积等性状进行遗传评估。根据育种值排名选择入选家系或个体,预测遗传增益。【结果】火炬松树高、胸径、材积、枝条数、枝条平均直径和枝条平均角在家系间存在显著的差异,具有较大的选择潜力。树高、胸径、材积和枝条平均直径之间均呈遗传正相关,单株遗传力范围为(0.1189±0.0383)^(0.3084±0.0532)。枝条平均直径与枝条数之间呈遗传负相关,单株遗传力分别为(0.0958±0.0357)和(0.0370±0.0278)。根据材积育种值,将前10名母本的子代作为入选群体,预测遗传增益为4.63%~5.10%。而根据材积育种值大小,将前10名个体作为入选群体,预测遗传增益达43.96%~48.43%。【结论】选出的优良家系与个体可作为下一代育种群体的候选材料。材积育种值前10的个体预测遗传增益高,可入选核心育种群体。

[Objective]Accurate genetic evaluation of loblolly pine progeny test plantation was conducted to improve the efficiency of breeding selection and genetic gain,and to determine the selected individuals for breeding population and reproduction population.[Method]More than 1800 individuals from 53 halfsibling families of loblolly pine were selected as the objects for genetic evaluation using the R and ASReml software.The genetic gain was predicted based on family breeding value or individual breeding value.[Result]There were significant genetic differences in height,DBH,volume,number of branches,mean diameter of branches and mean angle of branches among family lines of the torch pine,which showed great potential for selection.There was a positive genetic correlation among these traits(tree height,DBH,volume and mean diameter of branches),and the individual heritability was ranged from(0.1189±0.0383)to(0.3084±0.0532).There was a negative genetic correlation between the mean diameter of branches and the number of branches,and the individual heritability was(0.0316±0.0272)and(0.0958±0.0357),respectively.According to the family breeding value of volume,the offsprings of the top 10 female parents were selected as the selected population,and the predicted genetic gain was 4.63%-5.10%.However,the genetic gain was predicted to be 43.96%-48.43%based on the top 10 individuals,which were selected according to the breeding value of volume.[Conclusion]The superior families and individuals can be used as candidate materials for the next generation breeding population.The top 10 individuals of volume breeding value have higher predicted genetic gain and could be afforested by asexual propagation.