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基于不同林龄青海云杉遗传变异分析与早期选择评价

Analysis of Genetic Variation and Evaluation of Early Selection in Picea crassifolia Based on Different Forest Ages

  • 摘要: 为揭示青海云杉半同胞家系不同林龄生长性状的遗传变异规律并筛选优良材料,以113个青海云杉自由授粉家系5~17年生测定林为研究对象,分析了树高、地径/胸径、新梢、冠幅、材积等性状的方差分量、遗传参数、年际相关性,并开展了优良家系与单株的选择。结果表明:各性状在家系间均存在显著或极显著差异。树高的家系方差分量在各林龄均最高,机误随林龄持续下降,受遗传主效应控制最稳定;地径/胸径的机误始终占主导,受环境影响显著;新梢呈中等遗传控制;冠幅与材积受基因型 × 环境互作影响强烈。树高的家系遗传力为0.84~0.92,单株遗传力为0.21~0.43;胸径的家系遗传力为0.78~0.88,单株遗传力为0.18~0.32。年际相关分析表明,11年生时树高选择可靠性达88.2%,与17年生的相关系数超过0.90,表明11年生为最早可靠选择林龄。以5%入选率筛选出6个优良家系,树高现实增益18.26%,遗传增益16.25%;综合隶属函数值、主成分综合得分和指数选择法选出38株优良单株(树高均值683.95 cm),树高遗传增益达40.85%,三种方法重叠度大于80%。因此,青海云杉家系育种应以树高为核心选择性状,选出的优家系和优良单株可作为高世代育种核心亲本,青海云杉家系在11年生后可作为幼龄优选及良种审定的适宜树龄。

     

    Abstract: To elucidate the patterns of genetic variation in growth traits of Picea crassifolia half-sibling families and to screen superior materials,This study systematically analyzed variance components, genetic parameters, and age–age correlations for growth traits (tree height, diameter at breast height/ground diameter, current shoot length, crown width, and volume) in a progeny test plantation comprising 113 open-pollinated P. crassifolia families aged 5 to 17 years. Elite family and individual selection were subsequently conducted. Results showed significant or highly significant differences among families for all traits. Tree height exhibited the highest family variance components across all ages (49.98%~65.88%), with error variance consistently decreasing with age (44.68%~33.47%), indicating the most stable genetic control. In contrast, diameter growth was dominated by error variance (57.64%~67.54%) and was significantly influenced by environmental factors. Current shoot length showed moderate genetic control, while crown width and volume were strongly affected by genotype × environment interactions. Family heritability for tree height ranged from 0.84 to 0.92, compared to individual heritability of 0.21~0.43; for diameter, family heritability ranged from 0.78 to 0.88, with individual heritability of 0.18~0.32. Age–age correlation analysis indicated that selection reliability at age 11 reached 88.2%, with a correlation coefficient exceeding 0.90 with age 17, establishing age 11 as the earliest reliable selection age. Using a 5% selection rate, six elite families were selected, achieving a realized gain of 18.26% and a genetic gain of 16.25% for tree height. By integrating membership function values, principal component comprehensive scores, and index selection, 38 elite individuals were selected (mean height 683.95 cm), achieving a tree height genetic gain of 40.85%, with an overlap exceeding 80% among the three methods. Therefore, tree height should be used as the core selection trait in P. crassifolia breeding. The selected elite families and individuals can serve as core parents for advanced-generation breeding. For P. crassifolia families, age 11 and above is recommended as the suitable age for early selection and variety certification.

     

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