杉木单交F_(1)代的表型变异及杂种优势分析

Analysis of F_(1)representative variation and heterosis of Chinese fir

为定向创制杉木变异、开展家系内优良单株选择,以杉木优良杂交组合6421×27及其6年生单交F_(1)代群体为研究对象,对表征其形态、生长及材性的12个表型性状进行变异分析,探讨杉木优良种质形态、生长与材性性状的表型变异规律,以及性状之间的相关关系。结果表明:杉木F_(1)代群体的12个表型性状的变异系数范围为8.21%~37.97%,5个性状的变异系数达15%以上。在66对性状的相关关系中,中等强度的正相关关系占36.36%;木材基本密度的变异系数为8.21%,与其余11个性状均无显著相关性;131株F_(1)子代表现出正负两个方向的中亲优势,8个性状存在显性遗传效应,中优势率范围为-31.18%~90.44%,其中一级侧枝数存在明显的超亲优势;聚类分析把131株F_(1)子代分为3个大类群、6个亚群,各类群特征明显。杉木杂交子代在生长和分枝性状上具有较大的变异,浓密宽冠型杉木在幼龄期有明显的生长优势,杉木一级侧枝数存在明显的杂种优势,形态性状具有显性遗传效应。

For targeted variation creation in Chinese fir and selection of superior individuals within families,this study targeted the 6421 by 27 elite crosses and their 6⁃year F_(1)progeny from a single cross.Variation analysis was conducted on phenotypic values for 12 traits indicative of morphology,growth,and wood properties to explore phenotypic variation behaviors and inter⁃trait relationships in superior Chinese fir germplasm.Results revealed variation coefficients for the 12 traits in the F_(1)population from 8.21%to 37.97%,with five traits exceeding 15%.Among 66 trait correlations,36.36%showed moderate positive relationships.Basic wood density displayed a coefficient of variation of 8.21%,correlating non⁃significantly with the other 11 traits.In total,131 F_(1)offsprings displaying mid⁃parental heterosis in both directions,presented eight traits exhibiting dominant effects,and heterosis rates ranging from-31.18%to 90.44%,notably with first⁃order lateral branch number showing significant over⁃dominance.Cluster analysis divided the 131 F_(1)offsprings into three major and six sub⁃clusters,each with precise characteristics.F_(1)hybrids of Chinese fir showed substantial variation in growth and branching traits,with dense and broad⁃crowned firs having a pronounced growth advantage in the early stages.First⁃order lateral branch numbers in Chinese fir demonstrated apparent hybrid vigor,and their morphological traits showed dominant inheritance.