作物分子设计育种

优质、多抗、抗逆与高产作物新品种的选育和推广是实现我国粮食安全的重要途径。目前大多数育种工作仍然建立在表型选择和育种家的经验之上，育种效率低下；另一方面，生物信息数据库积累的数据量极其庞大，由于缺乏必要的数据整合技术，可资育种工作者利用的信息却非常有限。作物分子设计育种将在多层次水平上研究植物体所有成分的网络互作行为和在生长发育过程中对环境反应的动力学行为；继而使用各种”组学”数据，在计算机平台上对植物体的生长、发育和对外界反应行为进行预测；然后根据具体育种目标，构建品种设计的蓝图；最终结合育种实践培育出符合设计要求的农作物新品种。设计育种的核心是建立以分子设计为目标的育种理论和技术体系，通过各种技术的集成与整合，对生物体从基因（分子）到整体（系统）不同层次进行设计和操作，在实验室对育种程序中的各种因素进行模拟、筛选和优化，提出最佳的亲本选配和后代选择策略，实现从传统的”经验育种”到定向、高效的“精确育种”的转化．以大幅度提高育种效率。     

中国作物分子设计育种

分子设计育种通过多种技术的集成与整合,对育种程序中的诸多因素进行模拟、筛选和优化,提出最佳的符合育种目标的基因型以及实现目标基因型的亲本选配和后代选择策略,以提高作物育种中的预见性和育种效率,实现从传统的“经验育种”到定向、高效的“精确育种”的转化。分子设计育种主要包含以下3个步骤：(1)研究目标性状基因以及基因间的相互关系,即找基因(或生产品种的原材料),这一步骤包括构建遗传群体、筛选多态性标记、构建遗传连锁图谱、数量性状表型鉴定和遗传分析等内容;(2)根据不同生态环境条件下的育种目标设计目标基因型,即找目标(或设计品种原型),这一步骤利用已经鉴定出的各种重要育种性状的基因信息,包括基因在染色体上的位置、遗传效应、基因到性状的生化网络和表达途径、基因之间的互作、基因与遗传背景和环境之间的互作等,模拟预测各种可能基因型的表现型,从中选择符合特定育种目标的基因型;(3)选育目标基因型的途径分析,即找途径(或制定生产品种的育种方案)。本文评述近几年来我国在遗传研究材料创新、重要性状遗传分析、育种模拟工具开发和应用、设计育种实践、分子设计育种技术体系建设等方面取得的重要进展,结合国内外研究现状对分子设计育种的未来进行展望,最后指出我国近期应加强育种预测方法和工具、基因和环境互作、遗传交配设计、作物功能基因组学、生物信息学方法和工具、设计育种技术体系和决策支持平台等领域的研究,同时重视人才培养和团队建设。     

提高玉米育种效率的技术途径

在选育玉米新品种时,要提高育种效率,首先考虑的是应有一个明确的育种目标,其次是种质选择,同时还需考虑育种方法。提出“3群”杂种优势群的概念和“三角形”杂种优势模式;分析了轮回选择、二环选系、单倍体诱导选系的方法及分子育种技术对提高玉米育种效率的作用。结论是:要提高玉米育种效率,应在传统育种技术上下功夫,同时要重视现代生物技术作为辅助手段的应用。     

基于作物QTL的分子育种研究进展

分子标记技术和QTL(Quantitative Traits Loci)定位技术的迅速发展,使得以DNA多态性为基础的分子育种技术的研究不断深入,并在作物遗传育种中得到了一些成功的运用,为解决有关复杂性状的选择问题带来了希望。本文综述了近年来基于作物QTL的分子标记辅助选择及目标性状QTL克隆在作物的产量、品质、抗旱性等数量性状遗传育种中的主要应用,证实了分子育种的有效性;对目前影响分子育种效率的因素及存在的问题、应用前景进行了探讨。     

植物全基因组选择育种技术原理与研究进展

优势杂交育种是选育高产优质新品种的有效育种途径,该方法需要在田间选配大量的杂交组合进行试验。而作物的主要经济性状如产量等大多是数量性状,该类性状由多基因控制,受环境影响大,常规的育种选择过程耗时很长且选择能力有限。随着基因组测序技术和计算机科学的快速发展,通过高密度的分子标记准确预测作物产量等复杂性状成为可能。植物全基因组选择育种技术通过训练群体收集表型数据和基因型数据,使用特定的模型估计分子标记效应值或个体育种值,再根据待测群体的基因型数据和模型拟合结果对待测群体的表型值进行预测。全基因组选择育种技术可以对目标性状进行预测和定向选择,减少育种工作量,显著缩短育种周期,提高育种效率,具有广阔的应用前景。本研究从植物优势杂交育种预测方法研究进展、全基因组选择育种原理与模型算法研究进展、模型预测能力验证方法研究进展、植物全基因组选择育种应用、全基因组选择育种的局限性和植物全基因组选择育种展望等6个方面阐述植物全基因组选择育种的发展现状。     

稻瘟病抗性基因特异性分子标记的开发及应用进展

由稻瘟病菌引起的水稻稻瘟病是影响水稻生产的重要病害之一,培育和合理利用抗性品种是控制稻瘟病最经济有效、环保的措施。虽然DNA分子标记分子已经被广泛用于基于分子标记辅助选择技术(MAS)的水稻抗性育种工作中,但是分子标记辅助选择育种的效率取决于分子标记与目标基因的连锁距离。目前,已经克隆的稻瘟病抗性基因多达26个,其全基因组序列已经公开发表,这将有利于基因特异性分子标记的开发。基因特异性分子标记与基因共分离,在分子育种过程中实现了对目标基因的直接选择,有可能成为未来分子育种技术中鉴定目标基因的主流工具。本研究综述了稻瘟病抗性基因特异性分子标记的开发及应用情况,并对已经开发成功的基因特异性分子标记相关信息进行整合,旨在为育种家在分子标记的选择上提供指导信息。     

汕优63重组自交系评价

近年来．我国在水稻基础研究和水稻品种培育方面都取得了突破性进展．基于水稻基础研究和育种技术的全面提升．Peleman等提出了水稻“设计育种”（Breeding by designl的育种理念,即通过各种技术的整合与集成,对水稻生物体从基因（分子）到整体（系统）不同层次进行设计和操作．以达到育种目标．最大化满足人类对水稻品种的需求。     

分子标记技术在辣椒研究中的应用进展

分子标记是生物学研究的一个重要工具,在作物新品种选育等方面发挥着越来越重要的作用。为了构建辣椒分子标记辅助育种技术体系,以实现常规育种技术与现代生物技术的有机结合,归纳了分子标记技术在辣椒种质遗传多样性、分子连锁图谱构建、分子标记辅助选择育种和基因定位等方面的已有研究成果;认为分子标记技术在辣椒上的应用研究系统性还不强、基础分子信息比较缺乏、遗传图谱还不精细,建议在实用新型分子标记开发、核心种质分子信息库建立、优良作图群体及精细遗传图谱构建等方面加强系统深入的研究。     

中国作物分子育种现状与发展前景

近年来,随着基因组测序等多种技术实现突破,基因组学、表型组学等多门“组学”及生物信息学得到迅猛发展,作物育种理论和技术也发生了重大变革。以分子标记育种、转基因育种、分子设计育种为代表的现代作物分子育种技术逐渐成为了全世界作物育种的主流,在我国也正在成为作物遗传改良的重要手段。本文在界定分子育种的基础上,简要分析了中国作物分子育种研究现状和面临的问题,探讨了未来我国作物分子育种的发展策略。     

新品种

“洛新998”获国家小麦新品种保护，2008年山东省棉花良种补贴主推品种，湖北省通过审定的主要农作物新品种，“两优培九”超级稻种植超过1亿亩，安徽省推荐29个水稻主推品种，我国现代分子育种技术日趋成熟“863”作物新品种经济效益凸显     

Farmers’ participation and breeding for durable disease resistance in the Andean region

In the Andean region, the Preduza project and its partners combined breeding for durable disease resistance using locally adapted cultivars and farmer participatory methods. The approach taken resembles participatory variety selection (PVS). Farmers participated in the selection of advanced materials, rather than finished cultivars. This paper describes this approach and reports experiences with farmers–breeders collaboration. As breeders involved farmers as participants, they learned more about the most important criteria of male and female farmers for preferred cultivars in the marginal environments of Andean cropping systems. This approach encouraged the use of locally adapted cultivars (often landraces), made the breeders less dependent on foreign materials, and has resulted in selection and development of new wheat, barley, common bean, quinoa, potato and maize cultivars. Breeding programmes based on crossing locally adapted cultivars followed by selection by the breeders in the early phases of the breeding programmes and by participatory selection with the farmers in the more advanced stages of the breeding programmes appeared successful. It became clear that breeders must be well acquainted with the farmer preferences such as the requirements for specific agronomic, storage, processing and marketing traits. Over a period of five years the centralized formal breeding approach predominantly based on material produced by the international institutes was replaced by decentralized breeding approaches based largely on local germplasm with extensive farmer participation.     

Genomic selection and enablers for agronomic traits in maize (Zea mays): A review

Maize is a commodity crop providing millions of people with food, feed, industrial raw material and economic opportunities. However, maize yields in Africa are relatively stagnant and low, at a mean of 1.7 t ha⁻¹ compared with the global average of 6 t ha⁻¹. The yield gap can be narrowed with accelerated and precision breeding strategies that are required to develop and deploy high-yielding and climate-resilient maize varieties. Genomic and phenotypic selections are complementary methods that offer opportunities for the speedy choice of contrasting parents and derived progenies for hybrid breeding and commercialization. Genomic selection (GS) will shorten the crop breeding cycle by identifying and tracking desirable genotypes and aid the timeous commercialization of market-preferred varieties. The technology, however, has not yet been fully embraced by most public and private breeding programmes, notably in Africa. This review aims to present the importance, current status, challenges and opportunities of GS to accelerate genetic gains for economic traits to speed up the breeding of high-yielding maize varieties. The first section summarizes genomic selection and the contemporary phenotypic selection and phenotyping platforms as a foundation for GS and trait integration in maize. This is followed by highlights on the reported genetic gains and progress through phenotypic selection and GS for grain yield and yield components. Training population development, genetic design and statistical models used in GS in maize breeding are discussed. Lastly, the review summarizes the challenges of GS, including prediction accuracy, and integrates GS with speed breeding, doubled haploid breeding and genome editing technologies to increase breeding efficiency and accelerate cultivar release. The paper will guide breeders in selection and trait introgression using GS to develop cultivars preferred by the marketplace.     

桉树分子育种研究进展

桉树生长周期长,遗传杂合性高,许多重要经济性状属于多基因控制的数量性状,遗传机理不明,利用常规育种手段往往难以满足不同目的定向培育桉树新品种的要求。依靠现代分子生物学技术与常规育种技术相结合,可极大地缩短桉树育种周期,加速育种进程,对创造新种质,选育新品种具有重要意义。本文综述了国内外桉树基因工程育种、遗传图谱构建以及重要性状基因定位等分子育种的研究进展,提出了当前桉树分子育种中存在的问题,并展望了分子育种技术在桉树遗传改良中应用的前景。     

On the use of multiple lattice designs and α-designs in plant breeding trials

Plant breeders in Germany often use multiple lattice designs to test a large number of entries that are to be directly compared for selection. Comparison among entries from different lattices is accommodated by the use of checks. While this design has some practical merits, it is statistically expected to be less efficient than alternative designs for a large number of entries. In this note a study is made of the gain in efficiency by using a single large α‐design in place of multiple lattices. The comparison for a number of settings shows that the efficiency gain in terms of sample size or variance may be appreciable. It is concluded that plant breeders should seriously consider using α‐designs in place of multiple lattices. A simple method is described which allows breeders to study the potential gain for their particular design. Practical considerations leading to a preference of multiple lattices are critically discussed.     

Wheat breeding assisted by markers: CIMMYT’s experience

Significant progress has been made in the characterization of loci controlling traits of importance using molecular markers. A number of markers are currently available in wheat for genes of interest to the breeders. Markers can be used to better characterize parental material, thereby improving the efficiency and effectiveness of parental selection for crossing and to track genes in segregating progenies through the selection process. Although a number of breeding programs are using molecular markers at modest levels, the costs associated with marker assisted selection (MAS) are frequently cited as the main constraint to their wide-spread use by plant breeders. However, this is likely to change when user-friendly, high-throughput, automated marker technologies based on single nucleotide polymorphisms become available. These evolving technologies will increase the number of available markers, and will improve the efficiency, throughput, and cost effectiveness of MAS, thereby making it more attractive and affordable to many breeding programs. This article examines the extent to which molecular markers have been used at the International Maize and Wheat Improvement Center (CIMMYT) in applied wheat breeding and reviews the limited publicly available information on MAS from other wheat breeding programs. As markers are currently available for relatively few traits, we believe that MAS must be integrated with ongoing conventional breeding to maximize its impact. When used in tandem with phenotypic selection, MAS will improve response to selection for certain traits, thereby increasing rates of genetic progress.     

小麦育种策略探讨

小麦育种的理论、方法与技术早有详尽的研究,但是综合运用它们的策略尚有待发展,因为育种理论与方法需有育种实践的长期积累,并与育种理论结合才具实际意义。笔者所在单位近50年来育成了一系列小麦品种,成为新中国成立以来长江下游及中游部分地区小麦品种3次大面积更换的主体品种,是小麦杂交育种的成功范例。笔者根据长     

Fifteen years of co-operation between the government and industry in the sphere of agricultural plant breeding

Through the work of the Foundation for Agricultural Plant Breeding, S.V.P., the Government contributes to plant breeding in the Netherlands.The S.V.P. provides the breeders of agricultural crops with basic material comprising semi-products, the development of which may be expected to present the breeders with difficulties. It also conducts research, the results of which breeders could use to advantage. There are no strict regulations for the interplay between the Government and the breeder which specify that the latter has to take over and complete the work begun by the former.A close consultation between the breeders and the Foundation is possible through working groups of the Netherlands Breeders' Association. The ideas and desires of the provate breeders regarding governmental activities in the field of plant breeding can be brought up for discussion at meetings of the working groups.Fifteen years of experience in co-operation between private breeders and the Government are outlined. Although it is not always easy to satisfy all interests, it may be said that the present system of co-operation is greatly appreciated by all the parties concerned and that important results have been obtained.     

Impact of improved vegetable cultivars in overcoming food insecurity

Breeding is probably as old as agriculture itself. Early vegetable breeders developed landrace cultivars by selection of favorable variations in horticultural traits, yield and resistance to diseases and other problems. Later new breeding methods were developed, including hybridization techniques, culminating with the use of recently developed molecular tools, all leading to our modern improved vegetable cultivars. Great emphasis on protection of cultivars by seed companies, including development of F₁ hybrids, plant cultivar protection and patenting have been done. There were 392 vegetable crops cultivated worldwide but only slightly over one half of the total number of them have attracted commercial breeding attention. In recent times, there have been challenges and new trends in the breeding domain. These include an unrelenting movement away from well supported public breeding institutions to a breeding world dominated by private entities, and an increase in size of the companies in the private sector, with emphasis on the major vegetable crops. Almost half of the world vegetable farmers are poor and cannot afford to buy hybrid seed every growing season. Their economics and logistics make them difficult to buy expensive improved or hybrid cultivars since the lack of capital by subsistence farmers denies them the opportunity to invest in vegetable production inputs. If credit facilities and other input facilities are offered, improved or hybrid cultivars can have also a great impact on subsistence vegetable farmers overcoming their poverty and food insecurity. In last 50 years vegetable genetic resources are being lost, on a global scale at the rate of 1–2% per year. The multinational seed companies concentration in huge corporations have merged or canceled some vegetable breeding programs to reduce costs. Then there will be fewer vegetable breeders in the future and the growers will be dependent on a narrower genetic background, that could contribute in a near future, for food insecurity. Smaller seed companies, which are usually specialize in few vegetable crops, must be supported, possibly through autonomous affiliation with the larger companies. There is a need of investment in research breeding and cultivar development in traditionally open-pollinated cultivars and in the minor and so-called “forgotten” vegetables. More investments in this area will mean cheaper cultivars for growers to choose from and more preservation of vegetable biodiversity. In recent years, private plant breeding programs have increased in size and number. Financial investment also increased, as well as interest in intellectual property protection. Protective measures, especially patenting, must be moderated to eliminate coverage so broad that it stifles innovation. The intellectual property protection laws for plants must be made less restrictive to encourage research and free flow of materials and information. Public sector breeding must remains vigorous, especially in areas where the private sector does not function. This will often require benevolent public/private partnerships as well as government support. Intellectual property rights laws for plants must be made less restrictive to encourage freer flow of materials. Active and positive connections between the private and public breeding sectors and large-scale gene banks are required to avoid a possible conflict involving breeders’ rights, gene preservation and erosion. Improved and hybrid vegetable cultivars are, and will continue to be, the most effective, environmentally safe, and sustainable way to ensure global food security in the future.     

Breeding soybeans with resistance to soybean rust (Phakopsora pachyrhizi)

Soybean rust, caused by the fungal pathogen Phakopsora pachyrhizi, continues to be a global threat to soybean production, decreasing productivity and increasing the pesticide burden of cropping systems. However, breeders now have access to resistance genes that map to at least seven independent loci which can help protect crops against soybean rust infection. Efficient greenhouse screening protocols have been developed, and low‐cost SNP genotyping technology is available for marker‐assisted selection and backcrossing of resistance to Phakopsora pachyrhizi (Rpp) loci. Soybean breeders can now employ these technologies for the development of high‐yielding soybean cultivars with two, three, or even four pyramided Rpp genes. Such cultivars should provide resistance against the most virulent P. pachyrhizi populations and would be of great help to both large‐scale growers in the Americas and subsistence farmers in developing countries. We hope that a better understanding of the history and unique characteristics of P. pachyrhizi, the discovery of Rpp resistance alleles and the latest molecular breeding techniques will empower breeders across the globe to develop cultivars with durable resistance.     

Plant breeding: past,present and future

Plant breeders can help farmers increase food production by breeding new cultivars better adapted to their chosen farming systems, but these must be capable of providing the necessary plant inputs for the required levels of crop production in 2050. Until 200 years ago the farmers themselves were the plant selectors. Plant domestications, extensive crop dispersions and farmers’ selections produced thousands of locally adapted landraces of cultivated plants. During the twentieth century these were largely replaced by relatively few high yielding cultivars and the natural habitats of many of their wild relatives became endangered. Hence in situ and ex situ conservation, and evaluation and use of plant genetic resources is vital for future plant breeding. The development of scientific breeding from the beginning of the twentieth century was based on understanding the mechanism of inheritance and the mating systems of crop plants. The types of genetically uniform, high yielding cultivars that have been bred from genetically heterogeneous landraces were determined by the mode of reproduction and mating system of the cultivated plant species: inbred line (wheat) and hybrid (rice) cultivars for inbreeding species, hybrid (maize) cultivars for outbreeding species, and clonal (potato) cultivars for vegetatively propagated species. When genetically heterogeneous crops are desired, mixtures of cultivars and synthetic cultivars can be produced. Future progress in crop improvement will come from three complementary approaches: use of hybridization and selection in further conventional breeding, base broadening and introgression; mutation breeding, cisgenesis and gene editing; and genetically modified crops.