巨桉第二代育种群体遗传变异及早期选择研究

Genetic Variation and Early Selection of the Second Generation Breeding Population of Eucalyptus grandis

对广西东门林场3.2年生巨桉第二代育种群主要生长性状进行遗传变异和早期遗传型选择研究表明:家系平均树高、胸径、高径比和单株材积分别为10.1 m、9.3 cm、1.1和0.0446m3,且各指标在不同家系水平上存在极显著差异。树高、胸径、高径比和单株材积均受到相对较弱的遗传控制,遗传力分别为0.31、0.31、0.16和0.26,估算的遗传力均在合理范围之内。通过有效的遗传型选择,筛选出优良家系12个,树高、胸径和单株材积的遗传增益分别为18.9%、19.5%和42.2%;筛选出优良单株300个,树高、胸径和单株材积的遗传增益分别为15.4%、16.7%和36.7%,遗传增益显著。

A study on genetic variation and early genetic selection was carried out in the second generation breeding population of Eucalyptus grandis at the age of 3.2 years at Guangxi Dongmen state - owned Forest Farm. The study showed that the differences between families in tree height （HT）, diameter at breast height （DBH）, ratio of HT to DBH （H/D） and individual tree volume （VOL） were highly significant. For the best families, mean HT reached 10.1 m, DBH 9.3 cm, H/D 1.1 and VOL 0. 0446 m3. Growth traits were found to be under low genetic control with individual tree heritability （hi2） for HT being 0.31, for DBH 0.31, for H/D O. 16 and for VOL O. 26. A total of 12 superior families were selected, with the estimated genetic gain reaehing 18.9% for HT, 19.5% for DBH and 42.2% for VOL. Three hundred superior individual trees were selected and the estimated genetie gain with these was 15.4% for HT, 16.7% for DBH and 36.7% for VOL.