【目的】通过白桦(Betula platyphylla×B. pendula)半同胞家系区域性试验,评价其在不同试验点的生长特性及适应性,为优异家系的选择和应用以及种子园改建提供指导。【方法】以丹东、尚志和庆安试验点10年生四倍体与二倍体白桦半同胞家系试验林为研究对象,调查各家系树高、胸径、通直度及保存率等性状,采用异质方差混合线性模型,对各性状进行多地点固定和随机效应分析,通过BLUP-GGE联合分析法等估算各家系的综合育种值,结合GGE双标图分析各家系的适应性和稳定性。【结果】①白桦半同胞家系树高、胸径、单株材积和树干通直度等性状的地点效应差异显著(P<0.01);除树干通直度外,各性状在家系、区组间的差异以及家系×地点的互作效应均达到显著水平[方差分量及其标准误的比值(z._ratio)≥1.5]。②各试验点的方差分析表明,除庆安试验点保存率外,其余性状在家系间的差异均达到极显著水平(P<0.01)。丹东、尚志和庆安试验点各性状中变异系数最大的均为单株材积,分别为72.37%、56.37%和49.86%。③GGE 双标图分析表明,3个试验点被划分为3个适生区。在丹东、庆安和尚志试验点表现最好的家系分别为205、305和325号家系,其单株材积生长量较二倍体家系均值分别提高18.51%、2.60%和20.57%。按照20%的入选率,综合3个试验点,选出325和316等为速生性及稳定性优异家系,材积遗传增益分别为5.50%、12.92%。【结论】白桦家系各性状在试验点间和家系间的差异显著。基于生长性状的BLUP-GGE双标图分析结果,划分3个试验点为不同的适生区,筛选出325和316为速生性及稳定性优异家系。

【Objective】The purpose of this study is to assess the growth characteristics and adaptability of (Betula platyphylla×B. pendula) half-sib families through regional trials conducted at different test sites, thereby providing scientific guidance for the selection and application of superior families as well as the reconstruction of seed orchards. Specifically, the study aims to clarify the genetic variation patterns of key growth traits among families and across environments, and to identify families with excellent growth performance and wide adaptability.【Method】The research materials are from 10-year-old tetraploid and diploid (B. platyphylla×B. pendula) half-sib family test forests located in Dandong, Shangzhi and Qing’an test sites. Traits including tree height, diameter at breast height (DBH), stem straightness, and survival rate were systematically investigated in each family. A heteroscedastic mixed linear model was applied to analyze the fixed effects (e.g., site effects) and random effects (e.g., family effects, block effects, and family×site interaction effects) of each trait across multiple sites. The combined best linear unbiased prediction-genotype main effect plus genotype×environment interaction (BLUP-GGE) analysis method was used to estimate the comprehensive breeding values of each family, while GGE biplot analysis was employed to evaluate the adaptability and stability of families across different test sites.【Result】(1) The site effects on tree height, DBH, individual tree volume, and stem straightness of (B. platyphylla×B. pendula) half-sib families were extremely significant (P<0.01). Except for stem straightness, the differences in other traits among families and blocks, as well as the family×site interaction effects, all reached significant levels (the ratio of variance component to standard error (z._ratio) ≥1.5), indicating obvious genetic differentiation and environmental adaptation differences among families. (2) Analysis of variance for each test site revealed that, except for the survival rate at Qing’an test site, the differences in all other traits among families were extremely significant (P<0.01). Among all traits at Dandong, Shangzhi, and Qing’an test sites, the individual tree volume exhibited the largest coefficient of variation, which was 72.37%, 56.37% and 49.86%, respectively, indicating the highest genetic variation and selection potential. (3) GGE biplot analysis indicated that the three test sites could be divided into three distinct suitable growth regions due to differences in environmental conditions. The families that performed best at Dandong, Qing’an, and Shangzhi test sites were family 205, 305 and 325, respectively. Compared with the average value of diploid families, their individual tree volume growth increased by 18.51%, 2.60% and 20.57%, respectively. Based on a 20% selection rate and comprehensive evaluation across the three test sites, families such as 325 and 316 were selected as superior families with fast growth and high stability, with the genetic gains of individual tree volume reaching 5.50% and 12.92%, respectively.【Conclusion】There were significant differences in various traits of (B. platyphylla×B. pendula) families between test sites and among families, indicating the strong genetic control and environmental sensitivity of these traits. Based on the BLUP-GGE biplot analysis of growth traits, the three test sites were classified into different suitable growth regions. Families 325 and 316 were identified as superior families with fast growth and high stability, which could provide valuable genetic resources for the genetic improvement and sustainable management of (B. platyphylla×B. pendula) plantations.