水稻细菌性条斑病原菌的快速诊断

水稻细菌性条斑病是热带,亚热带地区水稻的一种严重病害。发病品种主要是籼稻,尤其是籼型杂交稻为高。我国条斑病发生面积呈扩大趋势,并能通过种子带菌传播,已被列为检疫对象。利用富含A蛋白的金黄色葡萄球菌与水稻条斑菌的抗血清结合,同待检样品进行协同凝集反应(coagglutination),即能迅速准确地进行早期诊断。在实验室及田间对该方法的特异性准确性进行了研究,并对青枯、白叶枯等的交叉及白叶枯的血清分型也进行了研究。     

两系法杂交水稻

七十年代初我国学者发现了“野败”细胞质和IR系统的恢复基因,成功地培育出了核质互作籼型杂交水稻,使得水稻产量有了大幅度提高。核质互作型杂交水稻是基于不育系、保持系、恢复系的配套实现不育系的繁殖、杂交种子(F_1)的生产的,因此三系法育种程序和生产环节复杂,选育新组合的周期长、效率低,同时杂种种子有成本高、产量低,这些都是三系杂交稻在种植面积上受到限制的原因。     

中国杂交水稻基因组计划

计划背景中国是世界上水稻种植面积最大的国家之一。中国及东南亚等主要水稻生产国都以水稻的另一亚种——籼稻及以籼稻为基础的杂交稻作为主要栽培品种。为开发杂交稻的宝贵资源,也为继续保持我国在杂交水稻育种领域的国际领先地位,中国科学院北京基因组研究所(原北京华大基因研究中心)于1999年开始筹划"中国杂交水稻基因组计划"。     

国内信息

超级杂交水稻基因组计划正式启动据悉 ,中国超级杂交水稻基因组计划 5月初在北京正式启动。北京华大基因研究中心、中国科学院遗传所植物生物技术实验室和国家杂交水稻工程技术研究中心的科学家将联手破译超级杂交稻的遗传密码 ,为进一步提高水稻产量和改善品质打下基础。与今年 4月美国孟山都公司宣布无偿公开的水稻基因组项目成果———水稻 (粳稻 )基因组工作草图有所不同 ,我国将进行的是籼稻杂交稻的基因组测序。取得粳稻和籼稻两套基因组的信息 ,将大大加快水稻的育种速度 ,并有望使我国成为最先实现“超级稻计划”的国家。“超级稻计…     

抗螟虫杂交稻“籼优63”培育成功

杂交稻在我国粮食增产方面具有重要的战略地位。利用优良恢复系“明恢６３”配制的杂交稻“籼优６３”在杂交稻品种中单位面积的产量最高,推广面积最大,年度种植面积达７００万公顷以上。但它和其它水稻品种一样受螟虫危害,产量损失巨大。据中国国家植保总站（１９９２）等单位对杂交稻生产大省湖南省的调查数据显示,在二化螟和三化螟严重发生的田块,水稻产量损失分别达到９８％和５０％。然而,迄今为止,在中国乃至全世界尚未找到对螟虫具有天然抗性的水稻品种。中国农科院生物技术研究中心范云六院士领导的实验室与华中农业大学张启…     

光敏核不育水稻育性转换的光温生态

光敏核不育水稻的花粉育性,可依种植地区与种植季节而变化。同一品系既可用作不育系而制杂交稻种子,又可自交繁殖而省去保持系。为水稻杂种优势利用改“三系法”为“二系法”开辟了新途径。光敏核不育材料育性可转换是该材料的宝贵之处。同时,这种可转换特性,特别是温度参预育性转换的调控引起的育性波动,给生产利用带来了一定困难。这种困难同其他科学研究中所遇到的困难一样,有待于进一步研究,加以     

水稻育性调控的分子遗传研究进展

杂交水稻为世界粮食安全做出了重要贡献。细胞质雄性不育和光/温敏不育分别是三系和两系杂交稻生产利用的遗传基础,而(亚)种间杂种不育则是杂交稻生产中要克服的主要技术瓶颈。因此,水稻育性调控是杂交水稻生产技术的关键,也是研究植物核质互作和物种生殖隔离等基础科学问题的重要模型。我国植物遗传学家在阐明杂交水稻育性调控的分子遗传基础领域做出了重要贡献。本文回顾了我国杂交水稻的发展历程,系统总结了杂交水稻生产涉及的细胞质雄性不育与恢复、光/温敏不育与育性转换、杂种不育与亲和性的遗传基础和分子作用机制,探讨了我国杂交水稻生产存在的问题,指明了水稻杂种优势利用的发展方向。     

NaCl对吸胀后水稻的种子发芽和幼苗生长的影响

用不同浓度的NaCl处理11个品种水稻吸胀后的种子,200mmol·L-1NaCl胁迫下,大多数品种的发芽率明显降低,品种间耐盐能力有异。杂交稻Lemont/七桂早及其亲本在盐胁迫下幼苗的生长受抑,干、鲜重和鲜重／干重值都有一定程度的下降,受害程度随着盐浓度的增加而加重。地上部比根部对盐害更为敏感。杂交稻Lemont/七桂早比其亲本的抗盐性稍强。     

杂交稻与螟害

通过三系配套育成的杂交水稻,已在全国各稻区广泛推广。大面积生产实践证明:杂交稻增产潜力无庸置疑;但螟害严重,尤其是大螟、二化螟的为害更为突出,是高产、稳产的一个障碍。因此,如何正确对待杂交稻螟害,是推广工作中务须认真研究和解决的问题。根据前人工作和我们的粗浅观察,对杂交稻螟害讨论如下。     

我国杂交水稻基因工程育种策略探讨

杂交水稻在我国水稻及粮食生产中占有突出地位 ,基因工程可在杂交水稻育种中发挥重要作用。针对杂交水稻育种存在的主要问题 ,指出应将优质、抗虫和抗病作为当前基因工程育种的研究重点。同时提出基因工程育种与常规育种紧密结合 ,优质基因工程着重改良保持系及聚合转基因等策略 ,以培育出超高产优质抗病虫转基因聚合杂交稻新组合。     

Strategy and utilization of a herbicide resistance gene in two-line hybrid rice

Hybrid rice plays an important role in China's aim to improve rice production as it accounts for some 50% of rice planting area but produces about 60% of the total rice grain. However, the existing three-line system used in hybrid rice production has its limitations. The two-line system, which makes use of photoperiod-sensitive genic male-sterile (PGMS) and thermo-sensitive genic male-sterile (TGMS) lines to generate the male-sterile parental line, was developed to overcome some of these limitations. The sterility of the male-sterile line of two-line hybrid rice, however, fluctuates when the temperature-sensitive phase of fertility encounters abnormal low temperatures during hybrid seed production, which induces selfing and decreases the purity of hybrid. We describe here the strategy of utilizing a herbicide resistance gene in two-line hybrid rice to eliminate this fluctuation in the sterility of the P/TGMS lines during hybrid seed production and reports the development of the herbicide resistance restorer line Bar68-1 and its herbicide-resistant early season hybrid rice Xiang125s/Bar68-1. When the restorer line and its derived hybrid are herbicide resistant, the selfed seeds can be removed easily from the hybrid by herbicide spraying. A herbicide resistance gene bar was transferred into a restorer line by particle bombardment. The resulting transgenic restorer line Bar68-1 and its hybrid Xiang125 s/Bar68-1 inherited stable herbicide resistance. The purity of Xiang125s/Bar68-1 was increased by spraying the seed bed with herbicide, which resulted in a significant increase in yield, grain quality, and disease resistance in comparison to the controls in a regional trial.     

中国科学家在杂种F1克隆繁殖研究领域取得突破性进展

杂种优势在提高作物产量和适应性方面已得到广泛应用。然而, 由于杂交种后代不能稳定遗传, 每年均需利用不育系和恢复系亲本配置杂交种子, 不仅制种成本高, 而且存在制种纯度问题, 限制了杂种优势利用的推广范围。近期, 中国科学家通过对减数分裂和受精过程关键基因进行编辑, 获得了杂种F₁的克隆种子, 为进一步固定杂种优势、实现“一系法”水稻杂种优势利用带来了曙光。     

Genic markers for wild abortive (WA) cytoplasm based male sterility and its fertility restoration in rice

Commercial exploitation of heterosis is essential for enhancing productivity of rice. The use of cytoplasmic male sterility (CMS) and fertility restoration system greatly facilitates large scale production of hybrid seed. The wild abortive (WA) cytoplasm is most widely used for hybrid seed production in rice. The present study was undertaken to develop molecular markers for both WA cytoplasm based male sterility and its fertility restoration for use in efficient hybrid breeding. High degree of genetic differentiation of WA-cytoplasm from its normal fertile counterpart was observed due to DNA rearrangements involving five (coxI, coxIII, cob, atp6 and rps3) mitochondrial genes. Cleaved amplified polymorphic sequence (CAPS) markers based on five mitochondrial genes namely, coxIII, cob, atp9, rps3 and 18SrRNA polymorphic between CMS and maintainer line were developed. The utility of these informative markers was demonstrated in purity testing of the CMS line Pusa6A being used in commercial hybrid seed production. Fertility restoration was found to be controlled by a major locus in the Basmati restorer line PRR78, which was mapped to a short marker interval of 0.8 cM and a physical interval of 163.6 kb on rice chromosome 10. A total of 13 pentatricopeptide repeat (PPR) motif containing genes were predicted in a 1.66 Mb region on the long-arm of this chromosome of which, four were present in the marker interval containing the fertility restorer gene. High degree of conservation of gene order was observed between japonica and indica for the predicted PPR genes. A sequence tagged site (STS) and a genic non-coding microsatellite (GNMS) marker were designed based on one of the candidate PPR motif containing genes present in the marker interval, which were validated using F₂ population and other known restorer lines. The candidate gene based marker identified in the present study would be useful in marker assisted selection (MAS) for fertility restorer gene in hybrid breeding programme based on WA-CMS of rice.     

Application of SSR markers for molecular characterization of hybrid parents and purity assessment of ICPH 2438 hybrid of pigeonpea [<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millspaugh]

With an objective of achieving a breakthrough in the productivity of pigeonpea, a hybrid breeding technology based on elements of the cytoplasmic-nuclear male-sterility (CMS) system and partial natural out-crossing has recently been developed. However, there is no molecular diversity information available on parental lines of hybrids being generated at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). This study deals with the use of 148 simple sequence repeat (SSR) markers, including 32 novel markers reported here for the first time, on 159 A (cytoplasmic male sterile), B (maintainer) and R (fertility restorer) lines. In total, 41 (27.7%) markers showed polymorphism with 2 to 6 (average 2.6) alleles and 0.01 to 0.81 (average 0.34) polymorphism information content (PIC) value. Of these polymorphic markers, 22 SSR markers showed polymorphism between A (ICPA 2039) and R (ICPR 2438) lines of the commercial hybrid (ICPH 2438); however, only 21 of these SSR markers showed the same profile between A (ICPA 2039) and B (ICPB 2039) lines. Finally, two SSR markers, CCB4 and CCttc006, were found most suitable for purity assessment of hybrid seeds of the ICPH 2438 hybrid. The utility of these two diagnostic SSR markers has been demonstrated by using seed lots of this hybrid from two sources, ICRISAT and Mahabeej. It is anticipated that molecular diversity information generated on parental lines of hybrids under development, and identification of the two most suitable markers for testing the purity of hybrid seeds of ICPH 2438, will facilitate the pigeonpea hybrid breeding programme.     

红莲型杂交稻(红莲2号)及其骨干亲本的RAPD分析与鉴定

利用RAPD技术,从248个随机寡核苷酸引物（10－mer）中筛出18个引物对红莲型杂交稻组合红莲2号及其亲本（T－07A、T－07B、YD6－05）,另6个红莲型胞质不育系的骨干恢复和汕优63及其亲本共14份水稻材料进行分析。共检测到173个多态性标记。聚类分析结果表明：不育系与保持系间因核背景相似,遗传差异很小;杂种（F1）的基因型更倾向于恢复系;恢复系与保持系间遗传距离的相对较大,但各恢复系之间的遗传距离较小。利用这些标记能有效地地区交组合中不育系,保持系、恢复系和杂种（F1）。     

利用SSR标记鉴定西瓜杂交种纯度的研究

以2个西瓜杂交品种(系)的种子黑公子和04-17及其亲本为材料,用SSR标记技术研究杂种与其双亲之间的扩增谱带多态性,以甄别真假杂种.结果发现,所试验的52对SSR引物中有13对引物分别在2个西瓜杂交种和其双亲之间存在扩增条带的多态性,表现为:多数SSR引物对自交系的扩增只出现1条带,但部分引物在某些自交系中扩增出2条带,杂交种条带均为父母本的互补型,很适合做杂交种纯度鉴定.用引物CMCT134b对黑公子和引物CMGA165对04-17进行了各100粒单种子SSR鉴定,所测纯度分别为96%和100%,与田间纯度95.6%和99.7%非常接近,表明SSR标记技术在西瓜杂交种子纯度室内快速检测中的应用前景.     

杂交水稻结实率稳定性的遗传分析

本文采用三套同核异质不育系与５个恢复力不同的恢复系按Ｐ×Ｑ模式配组、分５期播种的试验设计,在ＡＭＭＩ模型分析结实率稳定性的基础上,进一步剖析了不育胞质、保持系、恢复系及其工作的各种遗传效应。     

向日葵品种鉴定和纯度分析的AFLP研究

从杂交油葵A15及其亲本的1/2粒干种子中提取基因组DNA,选用17对引物组合进 行AFLP分析,构建了它们的指纹图谱。17对引物在A系与R系当中共扩增出1125条扩增产物,其中144条带表现出多态性,平均每对引物扩增66条带,不同引物组合产生的DNA片段数目在50～70之间,大小分布于100bp～500bp,多态性比率为12.8%。从中筛选出的2对引物E_AAC/M_CTC和E_ACG/M_CTG可将亲本和子代区分开：引物对E_AAC/M_CTC在A系中扩增出440bp、190bp、160bp 3条特征谱带,在R系中扩增出380bp、350bp、225bp、180bp 4条特征谱带,E_ACG/M_CTG在A系中扩增出了2条特征带480bp和265bp,在R系中扩增出490bp、220bp、205bp、125bp 4条特征谱带,且上述谱带均在子代中出现。用引物组合E_ACG/M_CTG对A15、双亲以及与A15外型十分相似的10个常用油葵杂交种进行AFLP分析,不仅表现出良好的多态性,并能够清楚地将它们加以区分。以其对50粒A15杂交种子进行纯度鉴定,得到与大田纯度检测一致的结果,说明使用AFLP标记检测油用向日葵的品种和纯度是可行的。对现行种子纯度和品种鉴定的方法进行了讨论。     

Application of RAPD and SCAR markers for purity testing of F1 hybrid seed in chili pepper (Capsicum annuum)

A simpler and better method for purity testing of hybrid pepper seed was developed. The simplest method for extracting genomic DNA, the NaOH method, was chosen. Two RAPD markers identifying male and female parents were also developed, and the PCR products of male- and female-specific RAPD markers were cloned and sequenced. From these sequences, new longer primers were constructed for conversion into SCAR markers. In blind tests the RAPD and SCAR markers were able to reliably detect contaminating exotic seeds. These PCR-based markers are therefore directly applicable for purity testing by seed companies. In addition, the PCR products of the SCAR markers could be identified by direct staining methods such as ethidium bromide and pellet painting without electrophoresis.     

Two non-allelic nuclear genes restore fertility in a gametophytic pattern and enhance abiotic stress tolerance in the hybrid rice plant

In indica rice, the HongLian (HL)-type combination of cytoplasmic male sterility (CMS) and fertility restoration (Rf) is widely used for the production of commercial hybrid seeds in China, Laos, Vietnam and other Southeast Asian countries. Generally, any member of the gametophytic fertility restoration system, 50% of the pollen in hybrid F(1) plants displays recovered sterility. In this study, however, a HL-type hybrid variety named HongLian You6 had approximately 75% normal (viable) pollen rather than the expected 50%. To resolve this discrepancy, several fertility segregation populations, including F(2) and BC(1)F(1) derived from the HL-CMS line Yuetai A crossed with the restorer line 9311, were constructed and subjected to genetic analysis. A gametophytic restoration model was discovered to involve two non-allelic nuclear restorer genes, Rf5 and Rf6. The Rf5 had been previously identified using a positional clone strategy. The Rf6 gene represents a new restorer gene locus, which was mapped to the short arm of chromosome 8. The hybrid F(1) plants containing one restorer gene, either Rf5 or Rf6, displayed 50% normal pollen grains with I(2)-KI solution; however, those with both Rf5 and Rf6 displayed 75% normal pollens. We also established that the hybrid F(1) plants including both non-allelic restorer genes exhibited an increased stable seed setting when subjected to stress versus the F(1) plants with only one restorer gene. Finally, we discuss the breeding scheme for the plant gametophytic CMS/Rf system.