圆角桉第2代家系遗传变异与中期选择

Genetic Variation and Mid-term Selection of Second Generation Eucalyptus tereticornis

为了选择遗传增益较高的圆角桉(Eucalyptus tereticornis)优良家系和优良单株,对4.4年生圆角桉第2代家系试验林进行生长性状分析与遗传评估。结果表明:参试的103个家系间D(胸径)、H(树高)、V(材积)存在极显著差异。胸径、树高、材积的家系遗传力>单株遗传力,两者都在0.5水平以上,表明家系受较强度遗传控制,单株均受中等强度遗传控制。以D、H、V这3个主要生长性状构建圆角桉家系和单株选择指数方程,用一个标准差水平选择出14个圆角桉优良家系,选择强度为13.59%,入选优良家系群体的D、H、V平均遗传增益分别达30.20%、20.55%、74.51%,最优家系为Y19、Y67、Y64;用2个标准差强度水平选择出52株圆角桉优良单株,入选率为3.12%,入选单株主要分布在36个家系中,其中有50%分布在优良家系中,选择效果明显。

In order to select elite families and superior individuals with high genetic gains,the growth traits and genetic evaluation of the second generation of 4.4-year-old Eucalyptus tereticornis were tested.Results showed that there were extremely significant differences inD,tree height(H),and volume(V)among 103 families.The family heritability ofD,H,andV was bigger than individual heritability,both of which were above the 0.5 level,indicating that family was under the control of higher genetic intensity and single plant was under the moderate genetic intensity control.Exponential equations for the selection of E.tereticornis fami?lies and individual plants were constructed based onD,H andV,and 14 elite families of E.tereticornis were selected with a standard deviation level,and the selection intensity was 13.59%.The average genetic gains of D,H andV in selected elite families reached 30.20%,20.55%,and 74.51%,respectively.The optimal families were Y19,Y67,Y64.52 superior individuals of E.tereticornis were selected by using two standard deviation intensity levels,and the selection rate was 3.12%.Selected individuals mainly distributed in 36 fam?ilies,among which 50%distributed in excellent families,and the selection effect was obvious.