林木基因型与环境互作的研究方法及其应用

我国是全球第一大木材进口国和第二大木材消费国,木材对外依存度已连续多年超过50%。然而,我国每公顷森林年均生长量约为林业发达国家水平的一半,这说明我国林木育种水平与林业发达国家相比仍有较大差距。因此,加强林木的规模化试验与精准遗传评估,通过林木良种的精确选育与推广对提高我国人工林的生产力水平具有重要意义。基因型与环境互作是林木规模化试验与精准遗传评估的重要环节之一。基因型与环境互作(G×E)是指基因型的相对表现在不同环境下缺乏稳定性,表现为不同环境下基因型排序变化或基因型间差别不恒定。现有研究证实,林木G×E很普遍且通常很大,要找到具有广泛适应性的优良基因型往往较困难。由于G×E会减小遗传力和遗传增益,因此了解G×E效应及其驱动环境因子,对育种设计、良种选育和种苗配置至关重要。本文归纳了目前研究G×E的主流分析方法(包括因子分析法、BLUP-GGE联合分析法)和遗传力的估算方法,也比较了这些G×E分析方法(包括稳定性分析、B型遗传相关、AMMI分析、GGE双标法、因子分析法和BLUP-GGE联合分析法)的优缺点,其次综述了全球重要经济树种(湿地松、火炬松、欧洲云杉、巨桉、辐射松、花旗松,等)近年来在生长性状(胸径、树高、材积,等)、形质性状(通直度、分枝角度、分枝大小,等)和材性性状(木材密度、弹性模量,等)的G×E研究进展,进而讨论了林木G×E的环境驱动因子及其应对策略,最后针对林木G×E研究新方法开发、加强多性状的G×E分析以及将基因组选择融入G×E分析方面对未来研究方向提出建议:1)新的林木遗传分析模型与G×E分析的联合应用;2)林木多环境、多性状的G×E的模式和幅度;3)特定环境的林木基因组育种值的精准估计。     

林木非生物胁迫抗性基因工程研究进展

干旱、极端温度和盐害等非生物胁迫因子是制约林木生长的重要因素。由于林木生长周期长, 且抗逆机制极为复杂, 长期以来, 如何改良林木对非生物胁迫的抗性一直是育种学家的难题。然而, 随着基因工程技术的发展, 人们可以在基因水平上改造林木, 提高其抗逆能力。文中主要介绍了林木抗逆基因工程的研究进展, 探讨了目前基因工程技术应用于林木抗逆育种研究存在的问题, 并对其应用前景进行了展望。     

林木遗传育种基础研究热点述评

林木由于世代周期长、个体高大、遗传负荷高等自身固有的一些特性,一直被认为是一种非常难以操作的遗传学材料,导致林木遗传育种在基础研究方面远远滞后于模式动、植物和其他重要作物,成为限制林木遗传改良进程的主要因素。分子育种是突破林木育种周期长的关键技术,通过基因组学研究,分析和阐明林木基因的功能是进行林木分子育种设计的前提。近年来随着生命科学领域新技术的快速发展,林木遗传育种基础研究也出现一些新的热点。本文主要阐述林木基因组和功能基因组学、连锁与关联分析、木材形成机制及分子育种技术的研究进展,虽然目前相关研究成果实际应用的条件还不成熟,但作为技术储备是急需加强的研究方向。     

林木全基因组选择研究现状和应用

全基因组选择（GS）是利用覆盖全基因组的高密度遗传标记对复杂数量性状进行预测的育种方法。在林木种苗阶段根据基因组估计育种值（GEBV）可以利用GS进行个体选择,相比常规育种能增强遗传增益、加快选育进程。该方法无需定位与性状相关的数量性状位点（QTL）,相比分子标记辅助育种能极大地提高对微效位点的捕获功效,是具有巨大潜力的林木育种策略。文中系统介绍了GS的概念和优势,及其在林木中的研究现状和应用。我国林木GS研究处于初期阶段,可优先在常规育种较成熟的树种中开展研究,建立林木GS程序为其他树种提供范式。该综述有助于系统了解全基因组选择育种策略和研究进展,并为全基因组选择在林木育种中的应用提供理论和技术信息。     

分子设计育种研究进展及其在林木育种中的应用

阐述了分子设计育种的概念、研究进展及其在动植物遗传育种中的应用。结合当前林木育种发展现状和育种目标, 介绍了开展林木分子设计育种的研究基础, 包括林木多基因转化技术研究、林木的分子标记辅助选择研究以及林木的生物信息学研究。针对林木分子设计育种现状, 分析了开展林木分子设计育种存在的相关问题, 并对今后的应用前景进行了展望。     

Development of economic forest tree breeding objectives: review of existing methodology and discussion of its application in Swedish conditions

Abstract

Genetic selection in forest tree breeding requires multiple traits to be considered simultaneously. Based on an economic breeding objective, traits are weighted according to their economic importance to create an index used for selection. Economic breeding objectives have mainly been developed in animal breeding and have only recently been applied to forest tree breeding. A review of the general methodology highlights the decisions associated with developing economic breeding objectives and their effects. Furthermore, studies concerning economic forest tree breeding objectives provide a bulk of knowledge and practical experience for fast growing, short rotation species. We have identified and discussed challenges when applying this methodology in Swedish tree breeding. Major challenges are: (1) managing the uncertainty of future industrial uses of wood and industrial processing, originating from long rotations; (2) various issues associated with having a production system describing an entire nation; (3) the size and effects of the discount rate; (4) developing models capable of representing genetic changes in the complex and dynamic system of growing and harvesting trees. We believe that these challenges must be tackled by a joint multi-disciplinary effort, involving stakeholders and researchers in several areas (e.g. forest genetics, economics, wood engineering), to make significant progress.     

植物转基因技术及其在林木遗传改良中的应用

转基因技术不断进步为基因的功能解析和生物的定向改良提供了最为有效的途径。林木基因工程育种也随着转基因技术的成熟而步入快速发展时期,但目前国内对林木基因工程育种中处于关键地位的转基因技术进行系统论述的还比较少。文中从原理、过程和优缺点等几个方面系统介绍了几种应用于植物基因工程的转基因技术,评述了转基因技术在林木中的应用现状,并对其在林木遗传改良中的应用前景进行展望,以期为后续的林木基因工程研究及应用提供参考。     

Breeding for value in a changing world: past achievements and future prospects

Large-scale tree improvement programs began in the 1950s. Tree improvement is now part of operational silviculture programs in many companies and countries around the world and tree breeding programs have produced very impressive results: (1) realized gains in plantations being established today of some 40–50 % in volume yield above unimproved material for many programs; (2) increased efficiencies in all aspects of breeding, selection, testing and deployment; and (3) a shortening of the generation interval by a factor of two from approximately 30 years in the first generation to less than 15 years today for pine programs. What about the future? What should tree breeders be thinking, planning and doing to ensure that results 60 years from now are even more impressive than those from the previous 60 years? Tree breeders today live in a rapidly changing world faced with: increasing demands for food, energy and water; globalization leading to an interconnectedness of markets and rapid spread of exotic organisms; climate change and its implications for genetic deployment; burgeoning technology in robotics, communications and molecular tools; shifting ownership patterns of forest land; and the real possibility of completely new forest products and markets in the future. Three ideas for “Breeding for Value in a Changing World” are: (1) adopt a robust philosophy that aims to ensure maximum value produced per ha even in a future world that will be quite different; (2) embrace technology at every phase in the tree improvement process; and (3) encourage interdisciplinary teams of scientists to solve complex problems that require expertise ranging from molecular to landscape scales.     

世界加速林木育种轮回研究的现状

林木育种事业向多世代发展, 通过缩短每一育种轮长度追求单位时间平均最大育种效益并降低育种作业成本, 已成为林木育种先进国家广为探讨的一个研究领域。决定缩短育种轮回的因素是如何克服林木始花龄晚和能否有效进行早期测验和选择。近20多年来欧洲和北美等国学者在上述两方面的研究中均取得了突破性进展, 使松科一些树种的育种轮比常规方法缩短1/2的时间。我国针叶树育种事业虽有近40年历史, 但这一领域的研究却几近空白, 与国际先进水平存在着质和量双重性差距, 严重限制着多世代育种的进展。本文在概述国外在这一领域的技术成就的基础上, 讨论了我国应采取的对策。     

林木遗传图谱的构建策略及存在的问题

遗传图谱是开展数量性状基因定位、标记辅助育种以及基因克隆等研究的基础,在理论和育种实践上都具有重要的意义,本文较为详尽地阐述了林木遗传图谱的构建过程,针对林木的自身特点探讨林木遗传图谱的作图策略,同时指出当前林木遗传图谱构建中存在的问题,并对林木高质量遗传图谱构建提出展望。     

Tree cavity densities and characteristics in managed and unmanaged Swedish boreal forest

In forests worldwide, ～10?40% of bird and mammal species require cavities for nesting or roosting. Although knowledge of tree cavity availability and dynamics has increased during past decades, there is a striking lack of studies from boreal Europe. We studied the density and characteristics of cavities and cavity-bearing trees in three categories of forest in a north-Swedish landscape: clearcuts with tree retention, managed old (>100 years) forest, and unmanaged old forest. Unmanaged old forests had significantly higher mean density of cavities (2.4?±?2.2(SD)?ha^?1) than managed old forest (1.1?±?2.1?ha^?1). On clearcuts the mean cavity density was 0.4?±?2.3?ha^?1. Eurasian aspen (Populus tremula) had a higher probability of containing excavated cavities than other tree species. There was a greater variety of entrance hole shapes and a higher proportion of cavities with larger entrances in old forest than on clearcuts. Although studies of breeding success will be necessary to more accurately assess the impact of forest management on cavity-nesting birds, our results show reduced cavity densities in managed forest. To ensure future provision of cavities, managers should retain existing cavity-bearing trees as well as trees suitable for cavity formation, particularly aspen and dead trees.     

Cavity and bark nesting bird response to partial cutting in Northern conifer forests

We investigated whether partial cutting used to mimic small-scale natural disturbances could maintain cavity and bark nesting breeding birds. We assessed changes in the relative abundance of cavity nesting birds in two intensities of partial cutting, compared to uncut and clearcut stands, 9 years post-treatment. We then examined the relationship between forest structure and nesting abundance (stand scale) and compared characteristics of used nest and forage trees to unused trees (tree scale). The relative abundance of most species was highest in either heavy removal or light removal treatments 9 years post-harvest. Brown creepers were most abundant in uncut, and red-breasted sapsuckers were most abundant in clearcut and heavy removal treatments. The proportion of deciduous trees and the density of dead trees were the best predictors of nest abundance. Individual nest tree use was predicted by the presence of large deciduous trees with broken tops and early to advanced stages of decay. Forage tree use was predicted by the presence of large conifer trees in advanced stages of decay. To maintain breeding habitat for cavity nesters, we suggest that forest managers retain the specific structural attributes required for nesting, but also the diverse forest conditions required for foraging.     

The genetic and economic gains from forest tree breeding programmes in Scandinavia and Finland

Plantations of genetically improved forest trees are critical for economic sustainability in forestry. This review summarizes gains in objective traits and the resulting economic impact of tree breeding programmes in Scandinavia and Finland. Genetic improvement of forest trees in these countries began in the late 1940s, when the first phenotypically superior plus-trees were selected from natural environments. The main findings from this review are that (i) tree breeding can increase volume growth in the range 10–25%, and (ii) the bare land value associated with genetically improved trees gives a better return on investment and a shorter rotation period compared to the unimproved forests. As some Nordic countries are quite dependent on the forest industry, breeding programmes that have resulted in economic gains have been beneficial for society. Growth and wood quality traits are often adversely correlated, and the weighting of traits from an economic perspective could provide an index for determining maximum profit from breeding. Tree breeding faces an array of challenges in the future, such as changes in silviculture, climate, new pests and diseases, and demand for wood-based products.     

林木遗传改良发展中的新见解

本文针对我国林木育种界中存在的问题,重点介绍了国际上已通过试验验证了的一些新见解。这些新学术见解正推动着世界林木遗传改良沿高效、低成本和快速的方向发展,对正处在发展中的我国林木育种事业有重要借鉴意义。合理吸收和利用它们将有助于使我国林木遗传改良向低成本和高速方向发展,以缩小与世界水平的差距。     

世界林木树种抗逆性育种研究进展

随着世界人口迅猛增长和工业化及大都市化进程的加快, 原有的森林树种将会遇到与自然选择下有重大不同的环境胁迫压力。为保障人类生存环境和生活质量不再劣化, 人类必须学会协助林木去更好更快地适应所遇到的各种随人类社会现代化而加剧和新出现的环境胁迫因素。低质量立地的造林利用技术和抗逆性育种就是摆在当代林学家面前的两大艰巨研究命题。为吸收国际先进经验来推动我国林木抗逆性育种事业, 作者对近些年来国际林学界在这一领域取得的研究进展作了综述。     

八角的遗传多样性与良种选育

就我国八角的遗传多样性与良种选育进行了分析,并提出了今后我国八角良种遗传改良的方向．认为我国八角栽培历史悠久,在自然选择下,其树形、分枝习性、叶、花、果实等方面出现了明显的差异性,遗传多样性丰富．目前,只有广西和云南进行了果用林优树选择,广西共选出128株优树,云南共选出18株优树;叶用林优良品种选育跟不上现实的需要．今后八角的良种选育将以优树选择为主,积极开展杂交育种,采取常规育种技术与生物技术相结合的育种技术以培育新的品种．     

林木良种化的经济政策分析

林木良种具有公共物品的特征, 需要政府扶持。但林木良种化是一项复杂的系统工程, 涉及良种选育、繁殖、生产、市场供需、利益分配机制等, 每个阶段和环节都有不同的特点, 要从公共财政现阶段的实际状况出发, 给予相应的政策支持。     

Genomic and physiological approaches to advancing forest tree improvement

The recent completion of a draft sequence of the poplar (Populus trichocarpa Torr. & Gray ex Brayshaw) genome has advanced forest tree genetics to an unprecedented level. A "parts list" for a forest tree has been produced, opening up new opportunities for dissecting the interworkings of tree growth and development. In the relatively near future we can anticipate additional reference genome sequences, including the much larger Pinus genome. One goal is to use this information to define the genomic attributes that affect the phenotypic performances of trees growing in various environments. A first step is the definition of ideotypes that constitute optimal tree and stand-level performance. Following this, the genome can be systematically searched for genetic elements and their allelic variants that affect the specified traits. Knowledge of these alleles and their effects will facilitate the development of efficient tree improvement programs through genome-guided breeding and genetic engineering and further our mechanistic understanding of trait variation. Improved mechanistic understanding of tree growth and development is needed to develop process models that will allow us to anticipate and manage change in forest ecosystems. Here we consider the development of an ideotype for loblolly pine (Pinus taeda L.) and discuss genomic approaches for studying the component traits that will enable advances in process model development and the genetic improvement of this important conifer.     

云南红豆杉优良单株初选

在收集整理有关资料的基础上,提出云南红豆杉优良单株初选标准,对形质指标提出定性要求;生物量指标拟合最优回归数学模型,得到优树选择最低基点和基线图;小枝叶紫杉醇含量根据预选群体计算其入选率与选择强度,以此为依据推算紫杉醇含量选择标准。     

转录组和代谢组在林木真菌病害防御反应中的应用研究进展

真菌病害是林木的主要生物胁迫之一，严重影响林业生态安全和经济效益。近年来随着组学技术的突破，转录组技术和代谢组技术已成功应用于林木真菌病害研究，主要包括致病和抗病关键基因的挖掘、林木防御物质的动态合成、抗病分子育种等方面，但林木如何抵御真菌病害及其两者间的互作机制仍是今后研究的热点与难点。文中通过对林木遭受真菌侵染后的转录组信息和代谢组信息进行探讨，包括类黄酮物质合成途径、植物激素信号转导、林木防御关键基因和关键代谢物、关键防御机制及功能网络等，将在理论上丰富林木响应真菌病害侵染的过程，为林木和真菌病害的互作研究奠定基础，并为林木抗性育种和化学防治提供参考；此外，基于目前转录组和代谢组在林木真菌病害防御反应方面的研究，对林木基因组研究、多组学联合研究以及病原菌组学研究等进行展望，以期为林木真菌病害研究提供新思路。