东北白桦半同胞子代表型变异分析与优良个体选择

Analysis on the Phenotypic Variations of the Half-sib Progeny of Betula Platyphylla var.Mandshurica and Selection of Its Fine Individuals

东北白桦是白桦的一个地理变种,具有适应性强、生长快、材质优良、用途广等显著特性。笔者以东北白桦半同胞子代异地保存林为对象,采取固定标准地连续定位测定的方法,探讨了树高、胸径和冠幅等性状的表型变异,综合评价了半同胞子代数量性状的遗传效应,在此基础上,广泛选择优良个体。研究结果表明,半同胞家系间树高、胸径、东西冠幅和南北冠幅4个性状存在一定的变异,平均变异系数分别为4.3 9%、2 2.9 0%、2 1.2 3%和2 5.2 0%,且树高、胸径和南北冠幅3个性状的差异极显著,东西冠幅差异显著;半同胞子代的数量性状受遗传基因控制程度较强,遗传力较强,遗传分化较小,遗传增益较高,4个性状的遗传力分别为0.9 8 3、0.7 55、0.6 6 6和0.7 9 6,遗传增益分别为3.2 1%、1 3.49%、1 1.52%和1 5.9 3%。综合考虑各项评价指标和各种影响因素,确定M R S 0 3为优良家系。

Betula Platyphylla var. Mondshurica is a geographical variety of Betula platyphylla with good adaptability,fast growth,fine texture,and a wide range of uses. In this paper the ex situ conserved forest of the half-sib progeny of Betula Platyphylla var. Mandshurica was the study object and the phenotypic variations of the characters including the tree height, DBH and crown breadth were studied with the method of continuous positioning measurement of fixed sample plots and the genetic effects of the half-sib progeny’s quantitative characters were comprehensively evaluated,and fine individuals were widely selected based on the results. The results showed that there were some variations among the 4 characters of the half-sib progeny families including the tree height,DBH,east-west and north-south crown breadths and the mean variation coefficients were 4.39%,22.90%,21.23% and 25.20% respectively. The differences of the characters including the tree height, DBH and north-south crown breadth were highly significant while that of the east-west crown breadth was significant. The half-sib progeny’s quantitative characters were highly controlled by the genes and have strong heritabilities with low genetic differentiation and high genetic gains. The heritabilities of the 4 characters were 0.983,0.755,0.666 and 0.796 respectively, and their genetic gains were 3.21%,13.49%,11.52% and 15.93% respectively. The family MRS03 was determined to be the finest with all the evaluation indexes and influence factors taken into account.