尾叶桉实生种子园遗传分析与育种值的估算Ⅰ.逆向选择方式建立种子园

对3年生尾叶桉实生种子园建园家系的生长性状、干形和枝冠形质性状及开花结实率的遗传分析表明:随林龄的递增,生长性状、干形和枝冠形质性状的遗传力在种源、家系和单株三层次逐渐变小并有稳定的趋势,且种源遗传力>家系遗传力>单株遗传力。利用BLUP方法估算家系和家系内个体育种值,并对建园家系、个体进行筛选,为种子园的遗传间伐提供依据。经遗传分析表明:尾叶桉SSObs种子园的遗传遵循加性 显性基因型遗传模式。从2个对照良种与建园家系的比较结果看,在SSObs种子园中,材积生长量大于CK1、CK2的优系有38个和39个,分别占建园家系总数的84.4%和86.7%;干形指标大于CK1、CK2的优系有30个和35个,占建园家系总数的66.7%和77.8%,表明建园的绝大多数家系其遗传品质是理想的。

Genetic Analysis and Breeding Value Estimation of Seedling Seed Orchard of Eucalyptus urophylla I.Establishment Based on Backward Selection

The Eucalyptus urophylla seedling seed orchard used in this study was established based on backward selection involving 45 families within 7 provenances.Results showed that there were highly significant differences in growth and stem form,rate of blossoming and other characters among families and provenances at the age of 3.The growth,stem form and tree crown of Eucalyptus urophylla were moderately or strongly hereditary at provenance,family and individual levels,and genetic coefficient variance of characters were minor by age increasing,and provenance heritablity>family heritablity>individual heritablity.Thirty-eight families(84.4% of the total) in SSO_(bs) produced higher stem volume than those of the control No.1(CK1),and 39 families(86.7%) were better than the control No.2(CK2) regarding the stem volume.These results showed that most of the parent materials in the SSO_(bs) had ideal genetic properties.Information obtained from estimating the breeding value()of family and individuals in family using BLUP method,and from the selection of ideal families and individuals,provided valuable evidence for the genetic thinning management of SSO_(bs).The genetic structure of E.urophylla in SSO_(bs) was considered to be the genetic mode of additive gene dominate gene.This result was vital for the management of the SSO_(bs) by thinning the inferior and reserving the superior.