杉木亲本的配合力测定

Test for the Combining Ability in Parent Clones of Chinese Fir

对林龄3或4年的杉木121个杂交组合,分析了种子场圃发芽率以及高、径、材积、冠幅的变异原因、配合力效应、杂种优势效应及遗传控制方式,并估算了生长性状的家系和单株遗传力。结果表明:小区内个体间差异是性状变异的主要原因,环境及遗传型×环境交互作用的影响也十分显著;双列杂交组合的高生长性状在遗传上主要是受基因显性效应的影响;生长性状配合力效应及杂种优势的表达都十分复杂;种子场圃发芽率及苗高的自交衰退非常严重。选出7个树高一般配合力表现优良的亲本,以及13个树高超群杂种优势平均12.85％的优良杂交组合。

121 crosses of Chinese fir (Cunninghamia lanceolat Hook. ) aged 3 or 4 were examined for their germination percentage on nursery bed,variations in height,diameter,volume and crown,amd their combining ability, heterosis and genetic control. Individual and family heritabilities were calculated for the growth traits. Most of the variation was attributed to the within-plot effects,and the significant effects of environment and genotype by environment interaction were observed. Dominance effects were predominant in the genetic control of height growth as suggested by the results from a diallel test. Expression of both the combining a-bility and the heterosis exhibited some complexity. High selfing depression occurred in the germination percentage and in the seedling height. Seven parent clones expressing superior general combining ability in tree height have been selected,and 13 crosses showing greater positive heterosis in tree height that averaged 12. 85% as compared with a control representing all the open-pollinated progenies within the seed orchard involved.