欧洲白桦裂叶与紫叶性状聚合：新种质创制及优异家系筛选

Combining dissected-leaf and purple-leaf traits in Betula pendula: development of new germplasm and selection of elite families

摘要

【目的】桦树是我国北方重要的观赏兼用材树种，但目前缺乏兼具裂叶与紫叶性状的新种质，制约了观赏兼用型品种的培育。本研究旨在创制裂叶紫叶桦树新种质，揭示裂叶与紫叶性状在回交后代中的分离特征及其与生长性状的关系。【方法】以裂叶绿叶品种‘Dalecarlica’为母本、正常叶紫叶品种‘Purple Rain’为父本杂交获得 F₁，再从 F₁ 正常叶紫叶群体中筛选优良单株与母本回交，构建 BC₁ 分离群体。对后代进行叶形、叶色鉴定及生长测定。利用卡方检验和连锁分析检测性状偏分离与连锁关系；通过 Logistic 生长模型解析紫叶性状与生长的动态权衡；估算家系遗传力，并采用隶属函数与熵权法进行多性状综合评价筛选优异种质。【结果】（1）BC₁ 群体中成功获得裂叶紫叶目标表型，频率为 26.01%。66.67% 的家系表型分离显著偏离孟德尔 1∶1∶1∶1 比例（ P < 0.05），其中 2 个家系绿叶表型完全缺失。连锁分析显示，f3、f4、f7、f10家系叶形与叶色基因间存在显著连锁信号，交换值 37.11% ~ 44.73%，平均 42.16%，表现为弱连锁。（2） 紫叶性状与株高生长呈负相关趋势，推测花青素积累与生长间存在资源分配权衡。紫叶性状（花青素含量指数）家系遗传力高达 97.91% ~ 98.97%；各表型类群的株高遗传力为 74.31% ~ 90.47%，具备高效定向选育潜力。（3）通过多性状综合评价，从回交群体中筛选出速生型、高观赏型及生长–观赏平衡型 3 类优异种质。【结论】回交育种可实现桦树裂叶与紫叶性状的有效聚合。BC₁ 群体中两性状存在偏分离与弱连锁特征，且紫叶性状与生长间呈动态权衡。本研究建立的基于遗传分离、生长表现和观赏性状的综合评价体系，可为观赏–用材兼用型桦树新品种选育提供种质材料和评价依据。

Abstract

[Objective] Birch is an important ornamental and timber tree species in northern China. However, new germplasm combining dissected-leaf and purple-leaf traits is currently lacking, which restricts the breeding of ornamental-timber dual-purpose cultivars. This study aimed to create new dissected-leaf purple birch germplasm and to reveal the segregation patterns of dissected-leaf and purple-leaf traits in backcross progenies, as well as their relationships with growth traits. [Method] The F₁ population was obtained by crossing the dissected-leaf green cultivar ‘Dalecarlica’ (Betula pendula ‘Dalecarlica’) as the female parent with the normal-leaf purple cultivar ‘Purple Rain’ (Betula pendula ‘Purple Rain’) as the male parent. Superior individuals with normal-leaf purple traits were then selected from the F₁ population and backcrossed with the female parent to establish the BC₁ segregating population. The progenies were evaluated for leaf shape, leaf color, and growth traits. Chi-square tests and linkage analyses were performed to detect segregation distortion and genetic linkage. The dynamic trade-off between purple-leaf traits and growth was analyzed using a Logistic growth model. Family heritability was estimated, and multi-trait comprehensive evaluation of superior germplasm was conducted using membership functions combined with the entropy weight method. [Result] (1) The target phenotype combining dissected leaves and purple leaves was successfully obtained in the BC₁ population, with a frequency of 26.01%. Phenotypic segregation in 66.67% of the families deviated significantly from the expected Mendelian ratio of 1:1:1:1 (P < 0.05), and the green-leaf phenotype was completely absent in two families. Linkage analysis showed significant linkage signals between the leaf-shape and leaf-color genes in families f3, f4, f7, and f10, with recombination frequencies ranging from 37.11% to 44.73% and an average of 42.16%, indicating weak linkage. (2) The purple-leaf trait showed a negative correlation trend with plant height growth, suggesting a possible resource allocation trade-off between anthocyanin accumulation and growth. The family heritability of the purple-leaf trait, represented by anthocyanin content index, was as high as 97.91%–98.97%, while the heritability of plant height among different phenotypic groups ranged from 74.31% to 90.47%, indicating strong potential for efficient directional breeding. (3) Through multi-trait comprehensive evaluation, three types of superior germplasm were selected from the backcross population, namely fast-growing, highly ornamental, and growth-ornamental balanced types. [Conclusion] Backcross breeding can effectively combine the dissected-leaf and purple-leaf traits in birch. In the BC₁ population, the two traits exhibited segregation distortion and weak linkage, and a dynamic trade-off was observed between the purple-leaf trait and growth. The comprehensive evaluation system established in this study, based on genetic segregation, growth performance, and ornamental traits, provides germplasm resources and an evaluation framework for the breeding of new birch cultivars with both ornamental and timber value.

关键词

欧洲白桦 / 观赏–用材兼用树种 / 回交育种 / 表型分离 / 家系遗传力 / 家系选择 / 紫叶性状 / 多性状综合评价

Key words

Betula pendula / ornamental–timber dual-purpose tree species / backcross breeding / phenotypic segregation / family heritability / family selection / purple leaf trait / multi-trait comprehensive evaluation

参考文献

[1] Kou J, Yan D, Qin B, et al. Physiological response mechanism of European birch (Betula pendula Roth) to PEG-induced drought stress and hydration[J].Frontiers in Plant Science, 2023, 14: 1226456.

[2] Lev-Yadun S, Keasar T. Prerequisites for evolution: variation and selection in yellow autumn birch leaves[J].New Phytologist, 2012, 195(2): 282-284.

[3] Santamour F S Jr, McArdle A J. Checklists of cultivars in Betula (birch) [J].Arboriculture & Urban Forestry, 1989, 15(7): 170-176.

[4] International Association of Horticultural Producers. Production and markets: the future of ornamentals [R/OL].International Association of Horticultural Producers, 2019. [2026−04−11].https://aiph.org/wp-content/uploads/2020/11/GIIC_AIPH-IVP-Production_Markets_Report2-2019.pdf.

[5] Qu C, Bian X, Han R, et al. Expression of BpPIN is associated with IAA levels and the formation of lobed leaves in Betula pendula ‘Dalecartica’[J].Journal of Forestry Research, 2020, 31(1): 87-97.

[6] Zhang X, Gu C, Jiang J, et al. Heritable epigenetic modification of BpIAA9 causes the reversion mutation of leaf shapes in Betula pendula ‘Dalecarlica’[J].Forests, 2024, 15(1): 95.

[7] Bian X, Qu C, Zhang M, et al. Transcriptome analysis provides new insights into leaf shape variation in birch[J].Trees, 2019, 33(5): 1265-1281.

[8] Gu C, Xu H, Yuan Q, et al. Epigenetic regulation of anthocyanin biosynthesis in Betula pendula ‘Purple Rain’[J].International Journal of Molecular Sciences, 2024, 25(22): 12030.

[9] Lin L, Mu H, Jiang J, et al. Transcriptomic analysis of purple leaf determination in birch[J].Gene, 2013, 526(2): 251-258.

[10] 田世龙, 马庆, 王阳, 等. 紫叶桦与裂叶桦杂交子代的种子活力及叶片性状分离[J].林业科学研究, 2019, 32(3): 40-48.

[11] Tian S L, Ma Q, Wang Y, et al. Segregation of seed vigor and leaf traits in hybrid progenies of Betula pendula ‘Purple Rain’ and Betula pendula ‘Dplecprlicp’[J].Forest Research, 2019, 32(3):40-48.

[12] Wu H X, Matheson A C. Genotype by environment interactions in an Australia-wide Radiata pine diallel mating experiment: implications for regionalized breeding[J].Forest Science, 2005, 51(1): 29-40.

[13] Cornelius J. Heritabilities and additive genetic coefficients of variation in forest trees[J].Canadian Journal of Forest Research, 1994, 24(2): 372-379.

[14] Verhulst P F. Notice sur la loi que la population suit dans son accroissement[J].Correspondance Mathématique et Physique, 1838, 10: 113-121.

[15] 刘东熙, 胡鑫, 张黄琛, 等. 基于熵权法赋权的广东典型红树林区域修复成效评价及差异分析 [J/OL].热带海洋学报, 2025 (2025−12−31). https://link.cnki.net/urlid/44.1500.P.20251229.2034.006.

[16] Liu D X, Hu X, Zhang H C, et al. Evaluation and variation analysis of restoration effectiveness in representative mangrove areas in Guangdong Province based on entropy weight model[J/OL].Journal of Tropical Oceanography, 2025 (2025−12−31). https://link.cnki.net/urlid/44.1500.P.20251229.2034.006.

[17] Morgan B T H. The Mechanism of Mendelian Heredity[M]. New York: Henry Holt and company,1923: 21-26.

[18] Xu X, Li L, Dong X, et al. Gametophytic and zygotic selection leads to segregation distortion through in vivo induction of a maternal haploid in maize[J].Journal of Experimental Botany, 2013, 64(4): 1083-1096.

[19] Fernandes J B, Naish M, Lian Q, et al. Structural variation and DNA methylation shape the centromere-proximal meiotic crossover landscape in Arabidopsis [J].Genome Biology, 2024, 25(1): 30.

[20] Gorringe N, Topp S, Burns R, et al. Natural variation modifies centromere-proximal meiotic crossover frequency and segregation distortion in Arabidopsis thaliana [J].Genetics, 2025: iyaf264.

[21] Kirungu J N, Magwanga R O, Shiraku M L, et al. Genetic map construction and functional characterization of genes within the segregation distortion regions (SDRs) in the F2: 3 populations derived from wild cotton species of the D genome[J].Journal of Cotton Research, 2020, 3(1): 32.

[22] Liu N, Lyu X, Zhang X, et al. Reference genome sequence and population genomic analysis of peas provide insights into the genetic basis of Mendelian and other agronomic traits[J].Nature Genetics, 2024, 56(9): 1964-1974.

[23] Kumar S, Mohapatra T. Dynamics of DNA methylation and its functions in plant growth and development[J].Frontiers in Plant Science, 2021, 12: 596236.

[24] Lucibelli F, Valoroso M C, Aceto S. Plant DNA methylation: An epigenetic mark in development, environmental interactions, and evolution[J].International Journal of Molecular Sciences, 2022, 23(15): 8299.

[25] Zhang H, Lang Z, Zhu J K. Dynamics and function of DNA methylation in plants[J].Nature Reviews Molecular Cell Biology, 2018, 19(8): 489-506.

[26] Ali S, Tang Y. Noncoding RNA-mediated regulation of DNA methylation: insights into plant epigenetic mechanisms[J].Journal of Plant Growth Regulation, 2025, 44(2): 373-388.

[27] Wang Q, Wang Y, Sun H, et al. Transposon-induced methylation of the RsMYB1 promoter disturbs anthocyanin accumulation in red-fleshed radish[J].Journal of Experimental Botany, 2020, 71(9): 2537-2550.

[28] 赵喜娟, 刘圣宣, 刘腾飞, 等. 转录组分析揭示光诱导转录因子 StMYB113 调控马铃薯块茎表皮叶绿素合成[J].作物学报, 2023, 49(7): 1860-1870.

[29] Zhao X J, Liu S X, Liu T F, et al. Transcriptome analysis reveals the regulatory role of the transcription factor StMYB113 in light-induced chlorophyll synthesis of potato Tuber epidermis[J].Acta Agronomica Sinica, 2023, 49(7): 1860-1870.

[30] Pascual M B, El-Azaz J, de la Torre F N, et al. Biosynthesis and metabolic fate of phenylalanine in conifers[J].Frontiers in Plant Science, 2016, 7: 1030.

[31] Qian Y, Lynch J H, Guo L, et al. Completion of the cytosolic post-chorismate phenylalanine biosynthetic pathway in plants[J].Nature Communications, 2019, 10: 15.

[32] Li Q, Liu Z, Jiang Z, et al. Phenylalanine metabolism-dependent lignification confers rhizobacterium-induced plant resistance[J].Plant Physiology, 2025, 197(2): kiaf016.

基金资助

国家重点研发计划(2021YFD2200304)