中国粮食作物的野生近缘植物及其保存概况

中国的主要粮食作物约有20种,它们的多数都有野生近缘植物.目前,中国保存的粮食作物野生近缘植物资源约1.5万份,分别保存在国家作物种质资源库和种质圃内.     

作物野生近缘种的原生境保护

作物野生近缘种是作物种质创新和品种改良的天然基因库,全球30%的作物增产得益于野生近缘种在作物育种中的利用。然而,由于生境破坏和污染、资源过度利用、盲目引种和气候变化等导致大量自然群体消失和群体遗传多样性丧失,对作物野生近缘种的繁衍和进化形成了严重威胁。原生境保护是在自然条件下对作物野生近缘种及其生态环境进行保护,维持其进化潜力,保护物种与环境互作的进化过程,是保护作物野生近缘种的重要途径之一。本文在分析国内外原生境保护政策和技术手段的基础上总结了作物野生近缘种原生境保护技术路线,综述了国内外对作物野生近缘种的原生境保护进展,并基于中国国情提出了作物野生近缘种存在的问题,探讨了未来作物野生近缘种原生境保护和野生近缘种可持续利用的发展方向和工作重点,强调把基因组、表型组和环境因子相关大数据与作物野生近缘种保护、研究和利用紧密结合,为作物野生近缘种的有效保护和高效利用提供强有力的理论和信息支撑。     

贵州少数民族地区作物稀有种质资源和野生近缘植物

"贵州农业生物资源调查"项目于2012-2014年已对贵州省21个县(市)进行了系统调查。系统调查的21个县(市)均有少数民族集居,各民族有不同的传统文化和生活习俗,在世代相传中赋予了当地作物种质资源丰富的民族文化内涵。并且,当地的地形地貌复杂,气候类型多样。正因为这种多样的自然条件和各异的民族文化,造就了这里丰富的作物稀有种质资源和野生近缘植物。本次调查获得的作物稀有种质资源和野生近缘植物,对作物的分类研究和新品种选育以及商业开发,将会有一定的利用价值。     

广西农作物种质资源遗传多样性

广西与云贵高原相连 ,具有多样化的地形和亚热带气候 ,农作物类型丰富。本文回顾近 5 0年来广西农作物种质资源研究的进展和现状 ,从作物的种类、分类学、评价鉴定利用情况 ,以及同工酶分析等基础研究 ,与中国起源有关的作物野生近缘种反映广西农作物种质资源的遗传多样性 ,2 0世纪 80年代以来 ,广西农作物资源的多样性迅速减少 ,本文对原地保存农作物种质资源的多样性提出商榷意见     

西部大开发必须抢救作物种质资源

我国西部作物种质资源十分丰富,尤以野生近缘种为最。3种野生稻大部分分布在西部。小麦野生近缘植物中,69％的物种只生于西部。野生大豆的多样性中心在西部——黄河中游。西部还有茶、柑橘、桃、李、梅、杏、山楂、樱桃、海棠、猕猴桃等多种干鲜果树和瓜菜的野生种。我国西部堪称农作物野生近缘植物的宝库。西部作物名特优品种和独特类型很多,如新疆的吐鲁番葡萄、哈密甜瓜、库尔勒香梨,宁夏的中宁枸杞,甘肃兰州的白兰瓜、百合等。过去考察中发现西藏有很多千年以上的古桑、光核桃子等。川西、陕南等地有稀有、珍贵的果、菜品种。我国在作物种质资源保护方面虽然做了大量工作,但是野生种损失严重,特别是分布较广的野生稻和野生大豆,多处分布点已大为缩小或绝迹。西部大开发中,生态环境不可避免地将发生变化。为了使种质资源不再继续损失,建议做好以下几件事：(1)在西部地区再进行一次作物野生近缘植物的考察收集;(2)通过调查,科学地建立野生近缘植物的保护区(点);(3)抢救栽培种的名特优种质资源,为发展特有产业储备物质基础;(4)保护好已收集的种质资源,勿使得而复失。     

中国农作物及其野生近缘植物多样性研究进展

本研究围绕粮食、经济、果树、蔬菜、饲草与绿肥、花卉六大类作物,以物种多样性和遗传多样性等为主线,开展了中国农作物及其野生近缘植物多样性研究,取得重大进展。科学界定和系统规范了种质资源概念和范畴,提出了层次结构的理论,查清了中国粮食与农业植物有9631个物种及其分布、特征特性及用途;深入研究了中国农作物种质资源的本底,首次明确了中国农作物总计有528种（类）,涉及1339个栽培物种和1930个野生近缘植物物种;优化了农作物种以下农艺性状分类技术指标,阐明了中国农作物地方品种的987个变种、978个变型、1223个农艺性状特异类型的植物学特征、生物学特性及其遗传多样性;得出了中国是禾谷类作物裸粒基因、糯性基因、矮秆基因和育性基因等特异基因的起源中心或重要起源地之一的结论;首次编撰出版了《中国作物及其野生近缘植物》专著6卷,并编撰了《中国粮食与农业植物物种名录》,形成了具有中国特色的作物种质资源学科理论体系。为农作物种质资源的高效利用、保障粮食安全和农业可持续发展奠定了基础。     

栽培植物野生近缘种的保护与利用

栽培植物是人类赖以生存和发展的重要物质基础。全球人口与人均需求量的持续增长导致对植物资源的需求与日俱增。栽培植物较低的遗传多样性是限制其产量增长和质量提高的主要因素。栽培植物野生近缘种在自然环境中积累了丰富的遗传变异, 并在应对环境变化的过程中产生了很多新的适应性状, 是栽培植物种质创新和品种改良的重要遗传资源。然而, 栽培植物野生近缘种的存续和自然进化因生境破坏以及全球气候变化等正面临严重威胁, 需要采取有效的措施进行保护。本文总结了国内外对栽培植物野生近缘种进行原生境保护与迁地保护所取得的进展, 并基于我国实际情况提出了栽培植物野生近缘种的保护建议。此外, 本文还对栽培植物野生近缘种利用技术进行了梳理, 探讨了栽培植物野生近缘种遗传资源可持续利用的新思路。最后, 我们以长江流域几种代表性栽培植物为例, 对主要作物类型的保护与利用情况进行了讨论。     

中国作物种质资源多样性

本文综述了中国作物种质资源的物种多样性和遗传多样性。按农艺学和用途可将中国作物分为8大类即粮食作物、经济作物、蔬菜作物、果树作物、饲用和绿肥作物、花卉作物、药用作物和林木作物。汇集了中国作物总计有840种（类）,涉及栽培物种1251个和野生近缘植物物种3308个,它们隶属176个科和619个属,这充分说明中国作物种质资源物种多样性相当丰富。依据中国作物的类型或变种多和性状变异幅度大,阐明了中国作物种质资源遗传多样性十分丰富。为中国作物种质资源的收集、保护、高效利用、创新、分类和遗传研究奠定了坚实基础,为生物多样性保护提供了科学依据。     

牧草种质资源中心库存资源的多样性及其利用

对我国牧草种质资源中心库入库资源的多样性进行了综述。入库资源种类及种质类型多样,特有牧草种质资源突出,栽培牧草的野生祖型及野生近缘种、优良牧草种类多;对牧草种质资源中心库入库资源的开发利用情况进行了介绍;建议今后扩大种质搜集、加强研究、规范入库资源的质量控制,为牧草种质资源的高效利用奠定基础。     

作物野生近缘植物保护与可持续利用

作物与人类文明的传承和发扬密不可分。世界人口和人均需求量的持续增加导致植物资源的供需失衡。作物自身相对较低的遗传多样性是影响产量和品质的主要因素。作物野生近缘植物在生境中积累了多种基因型，并在应对环境变化时形成了多种表现型，是作物种质保护和品种改良的重要遗传资源。但随着生境破坏以及全球气候变化等不确定因素的持续影响，使得作物野生近缘植物的存活和繁殖质量受到了严重威胁，必须采取有效的措施进行保护。本文总结了国内外对作物野生近缘植物保护工作所取得的进展，应对我国在保护中存在的问题提出相应的改良建议。最后以国内代表性作物为例，对其保护与利用情况进行了讨论。     

中国作物野生近缘植物资源

中国地域辽阔,气候多样,地形复杂,土壤类型繁多,加之农业历史悠久,不仅作物种类众多,而且很多作物都有其野生近缘种,从而使得中国成为世界作物的重要起源中心之一。本文在介绍中国作物种类的同时,列出了各类作物的野生近缘植物资源,为进一步深入研究和开发利用这些资源,以及国家制定野生植物保护有关政策提供基础数据和信息。     

Preservation of plant genetic resources in the biotechnology era

Thousands of years ago humans began domesticating crops as a food source. Among the wild germplasm available, they selected those that were best adapted for cultivation and utilization. Although wild ancestors have continued to persist in regions where domestication took place, there is a permanent risk of loss of the genetic variability of cultivated plants and their wild relatives in response to changing environmental conditions and cultural practices. Recognizing this danger, plant ex situ genebank collections were created since the beginning of the last century. World-wide, more than 6 million accessions have been accumulated including the German ex situ genebank in Gatersleben, one of the four largest global collections, housing 150,000 accessions belonging to 890 genera and 3032 species. This review summarizes the ex situ plant genetic resources conservation behavior with a special emphasis on German activities. Strategies for maintenance and management of germplasm collections are reviewed, considering modern biotechnologies (in vitro and cryo preservation). General aspects on genetic diversity and integrity are discussed.     

转基因植物对农业生物多样性的影响

论述了近年来转基因植物对农业生态系统生物多样性影响的研究进展．主要在遗传多样性、物种多样性和生态系统多样性3个层次上予以评述．包括转基因植物对作物遗传多样性的影响;转基因植物的外源基因向杂草和近缘野生种转移;转基因抗虫植物对目标害虫的影响。抗除草剂转基因植物对作物和杂草的影响,抗病毒转基因植物对病毒的影响;转基因植物对非目标生物的影响,对土壤生态系统的影响等．     

In situ conservation of crop genetic resources through maintenance of traditional farming systems

A strategy is suggested for in situ conservation of crop genetic resources whereby conservation efforts are linked to rural development projects in Third World countries. We describe development projects that emphasize preservation of traditional farming systems and succeed in sustaining production by relying on the maintenance of biological and genetic diversity in these systems. Basing agricultural development efforts on indigenous knowledge, technology, and social organization can provide important guidelines for the design of cropping systems that allow lowincome farmers to produce subsistence and cash crops without dependence on external inputs and seed supplies. By incorporating landraces and wild relatives of crops into these cropping systems, major achievements in the conservation of crop genetic resources can be obtained.     

Transgene escape: what potential for crop–wild hybridization?

To date, regional surveys assessing the risk of transgene escape from GM crops have focused on records of spontaneous hybridization to infer the likelihood of crop transgene escape. However, reliable observations of spontaneous hybridization are lacking for most floras, particularly outside Europe. Here, we argue that evidence of interspecific reproductive compatibility derived from experimental crosses is an important component of risk assessment, and a useful first step especially where data from field observations are unavailable. We used this approach to assess the potential for transgene escape via hybridization for 123 widely grown temperate crops and their indigenous and naturalized relatives present in the New Zealand flora. We found that 66 crops (54%) are reproductively compatible with at least one other indigenous or naturalized species in the flora. Limited reproductive compatibility with wild relatives was evident for a further 12 crops (10%). Twenty-five crops (20%) were found to be reproductively isolated from all their wild relatives in New Zealand. For the remaining 20 crops (16%), insufficient information was available to determine levels of reproductive compatibility with wild relatives. Our approach may be useful in other regions where spontaneous crop-wild hybridization has yet to be well documented.     

试论野生稻资源遗传多样性原生境保存

我国野生稻资源丰富,分布地域广阔,由于经济建设用地需要,近年来野生稻原生地遭到严重破坏,野生稻原生境保存已是十分紧迫的事情。本文论述了原生境保存的意义,原生境保存地的选择原则及设想,旨在提高全民生态保护意识,加强野生稻资源保护。     

Sequence evidence for sporadic intergeneric DNA introgression from wheat into a wild Aegilops species

Introgressive hybridization has played a crucial role in the evolution of many plant species, especially polyploids. The duplicated genetic material and wide geographical distribution facilitate hybridization and introgression among polyploid species having either homologous or homoeologous genomes. Such introgression may lead to the production of recombinant genomes that are more difficult to form at the diploid level. Crop genes that have introgressed into wild relatives can increase the capability of the wild relatives to adapt to agricultural environments and compete with crops or to compete with other wild species. Although the transfer of genes from crops into their conspecific immediate wild progenitors has been reported, little is known about spontaneous gene movement from crops to more distantly related species. We describe recent spontaneous DNA introgression from domesticated polyploid wheat into distantly related, wild tetraploid Aegilops peregrina (syn. Aegilops variabilis) and the stabilization of this sequence in wild populations despite not having homologous chromosomes. Our results show that DNA can spontaneously introgress between homoeologous genomes of species of the tribe Triticeae and, in the case of crop-wild relatives, possibly enrich the wild population. These results also emphasize the need for fail-safe mechanisms in transgenic crops to prevent gene flow where there may be ecological risks.     

Projecting the effects of climate change on the distribution of maize races and their wild relatives in Mexico

Climate change is expected to be a significant threat to biodiversity, including crop diversity at centers of origin and diversification. As a way to avoid food scarcity in the future, it is important to have a better understanding of the possible impacts of climate change on crops. We evaluated these impacts on maize, one of the most important crops worldwide, and its wild relatives Tripsacum and Teocintes. Maize is the staple crop in Mexico and Mesoamerica, and there are currently about 59 described races in Mexico, which is considered its center of origin . In this study, we modeled the distribution of maize races and its wild relatives in Mexico for the present and for two time periods in the future (2030 and 2050), to identify the potentially most vulnerable taxa and geographic regions in the face of climate change. Bioclimatic distribution of crops has seldom been modeled, probably because social and cultural factors play an important role on crop suitability. Nonetheless, rainfall and temperature still represent a major influence on crop distribution pattern, particularly in rainfed crop systems under traditional agrotechnology. Such is the case of Mexican maize races and consequently, climate change impacts can be expected. Our findings generally show significant reductions of potential distribution areas by 2030 and 2050 in most cases. However, future projections of each race show contrasting responses to climatic scenarios. Several evaluated races show new potential distribution areas in the future, suggesting that proper management may favor diversity conservation. Modeled distributions of Tripsacum species and Teocintes indicate more severe impacts compared with maize races. Our projections lead to in situ and ex situ conservation recommended actions to guarantee the preservation of the genetic diversity of Mexican maize.