四川桤木杂交子代苗期性状遗传分析及选择

Genetic Analysis and Selection of Morphological Traits of Alnus cremastogyne Burk. Hybrid Offspring

人工杂交和杂种优势利用是林木遗传改良的重要途径。研究四川桤木杂交子代的生长表现,为杂交四川桤木品种选育提供参考依据。以12个四川桤木优树和1个欧洲桤木优良品种为亲本,按照NCⅡ交配设计进行控制授粉,测定1 a生种苗的苗期性状,结果显示,四川桤木杂交子代苗高和地径在家系间存在极显著差异。一般配合力效应在同一亲本不同性状及同一性状不同亲本间存在明显差异,母本JT4各性状的一般配合力效应值相对较大。不同家系各个性状的特殊配合力差异显著,家系F6苗高的特殊配合力效应值最大,家系F36地径的特殊配合力效应值最大。各性状的广义遗传力均较高,其中苗高的广义遗传力超过50%。综合分析表明,四川桤木杂交子代的苗期表型性状差异显著,可进行家系间和家系内的初步选择,JT4、JG6和BZ6作母本,LD8和XH5作父本的一般配合力较高,初步认为这5个亲本为优良的杂交育种亲本资源。家系F6、F32、F36和F42的苗高和地径特殊配合力相对较高,可用于进一步杂交选育四川桤木良种。

Crossbreeding and utilization of heterosis were the key ways of forest tree improvement. A NC II design was conducted with twelve plus trees of A. cremastogyne Burk. and one improved breeds of A. glutinosa. Phenotypic traits of one year seedlings were measured to reveal the growth performance and genetic stability of crossbreeding seedlings, and to provide reference for breeding of A. cremastogyne. The results showed that there were very significant differences between families in height and diameter. An obvious difference of the general combining ability （GCA） existed between different traits with the same parents or between different parents with the same traits. JT4 as a female parent had a relatively higher GCA value than other parents. There were significant differences of special combining ability （SCA） between families, F6 had the most SCA value in height, F36 had the most SCA value in diameter. High broad-sense heritability existed in all traits,with the broad-sense heritability of height above 50%. Comprehensive analysis showed that significant differences occurred between hybrid offspring, so primary selection of seedlings among and within families was workable. JT4, JG6 or BZ6 （as female parents）, LD8 or XH5 （as male parents） had a high GCA value. It was primarily thought that these parents could be served as the better parents resources of crossbreeding. F6, F32, F36, and F42 could be used for breeding in A. cremastogyne because of their higher SCA value in height and diameter than other families.