温敏核不育系株1S籼粳的属性研究

温敏核不育系株1S是生产上广泛应用的水稻优良早籼型不育系品种。以典型籼稻和粳稻为对照,采用ISSR、SRAP和TRAP三种分子标记方法对株1S核DNA进行分子遗传学分析。结果表明,株1S核DNA以籼型基因为主,但含有部分粳型特异性片段,具有一定的粳型血缘;3种分子标记方法都能建立株1S所特有的分子指纹。对株1S叶绿体DNA中ORF100、ORF29-TrnC^GCA、TrnT^UGU-TrnL^UAA、rps16基因内含子等序列分析表明,株1S为籼型叶绿体,对照材料培矮64S、准S为粳型叶绿体;株1S在TrnT^UGU-TrnL^UAA片段中存在2个特异碱基。利用籼型细胞质和含有适量粳稻血缘的两用核不育系可能是长江中下游双季稻区高产稳产早稻组合的育种途径。     

两用核不育系水稻叶绿体DNA的比较研究

以典型籼稻和粳稻作对照,对湖南应用较广的几个两用核不育系进行叶绿体DNA的ORF100、ORF29-TrnCGCA片段长度以及rps16基因内含子和TrnTUGU-TrnLUAA转录间区2个片段序列进行比较研究。结果表明,株1S、陆18S、株77S、H628S、88S、白天鹭S、G0543S、G03S、1103S和W6154S的叶绿体DNA的ORF100、ORF29-TrnCGCA两片段的大小均与典型的籼稻一致,其他材料则与典型粳稻相同;叶绿体DNA碱基多态性较丰富的2个区域rps16基因内含子和TrnT UGU -TrnL UAA间区的测序后发现4个籼粳稻特异位点,这4个位点对两用不育系叶绿体籼粳属性的判断与ORF100、ORF29-TrnCGCA片段的结果一致。根据育出组合的数量和质量,带有粳型血缘细胞质的两用核不育系如准S、810S、、中心S、C185S和培矮64S等显现了一定的优势。研究结果说明,通过籼粳稻杂交选育具粳稻血缘的籼型不育系是提高杂交水稻产量的有效途径之一。     

水稻不同组织总DNA对叶绿体标记分析的影响

叶绿体DNA标记是水稻分子生物学分析中的常用方法之一。但是水稻叶绿体DNA的提取过程复杂且耗时,为了简化分析步骤,本试验使用CTAB与SDS方法分别提取栽培水稻籼93-11和粳沈农265的叶、根、种子3种组织总DNA,选择3对叶绿体基因间隔区标记(psbA-trnH、petG-trnP和infA-rpl36)以及2对水稻叶绿体籼粳分类标记(ORF100和ORF29-TrnCGCA)进行PCR扩增。结果显示以它们种子、根为模板的扩增效果与叶片模板的扩增效果相一致,并与预期的结果相符合。最后对60份杂草稻种子总DNA进行叶绿体籼粳分类标记扩增分析,结果表明,杂草稻种子总DNA中扩增出目的片段同样能够进行有效的籼粳分类。这在一定程度上简化了水稻叶绿体标记的分析过程,加快分析速度。     

水稻光温敏核不育系的ISSR和SSR遗传分析比较

本研究应用ISSR和SSR技术建立了24个水稻光温敏核不育系的DNA指纹图谱，利用13个ISSR引物和20对SSR引物，分别获得174个多态性片段和62个多态性片段，平均每个ISSR引物检测到13．38个多态性片段，远远高于SSR引物的检测率。根据遗传距离进行的聚类分析表明，利用这两种标记所得的聚类结果十分相似，24个材料被聚为粳型，偏籼型和籼型三个类群，在籼型不育系类群内，又可明显的分成三个亚类群，其中7个安农S-1衍生的不育系聚为一类，与农垦58S衍生的不育系有明显的遗传差异。根据两种标记计算的遗传距离及其遗传关系，所得的结果仍有一些差异，但总体趋势是一致。研究结果表明，ISSR和SSR标记适用于构建DNA指纹图谱，进行分类鉴定和遗传分析。     

分子标记辅助选育抗稻白叶枯病的低温敏核不育系3178S

本研究以IRBB21为Xa21基因供体，籼型低温敏不育系399S为低温核不育系基因供体，采用杂交和回交方法，逐代用分子标记检测手段，导入广谱抗白叶枯病基因Xa21和低温敏核不育系基因，聚合双亲的有利性状，育成抗白叶枯病的籼型低温敏核不育系3178S，其抗性达到了IRBB21的抗性水平，且保持了399S稳定的育性和双亲的优良经济性状。     

水稻雌性核不育系SNP指纹图谱及抗逆相关差异位点检测

本研究以育成的‘云岭’系列水稻雌性核不育系为材料,利用水稻56K SNP芯片,构建水稻雌性核不育系SNP分子指纹数据库,同时检测分析其抗逆相关差异位点。结果表明,56K水稻SNP芯片共筛选出32 727个标记位点,并利用12 475个多态性SNP位点的物理位置构建了分子指纹图谱。籼粳组分分析发现10个雌性核不育系的粳型组分比例均大于籼型组分比例,‘云岭301FS’～‘云岭305FS’的籼型组分明显小于‘云岭306FS’～‘云岭310FS’,且籼粳位点差异明显。水稻雌性核不育系的抗逆相关基因主要有8种类型,共有41个基因,包含160个位点,表明供试的水稻雌性核不育系拥有良好的抵抗相应逆境的分子基础。通过比对参考基因组,发现一些基因的CDS区碱基发生不同程度的转换、颠换,其中有6个位点的改变导致了同义突变,13个位点的改变导致了错义突变,这可能导致多肽链原有功能的改变,最终影响水稻抵抗逆境的能力。本研究结果将为雌性核不育系的分子鉴定及其优良抗逆特性的研究提供理论基础。     

短日、低温粳稻不育新种质8608S的育性遗传初析

迄今,国内外水稻科研工作者已发现多个籼型短日、低温诱导不育系和长日、高温诱导不育系,而粳型短日、低温不育系却少见报道。最近,中国农业科学院和江苏省农业科学院联合选育出粳稻短日低温敏核不育新种质8608S,其在长日高温条件正常结实,在短日低温条件下不育;遗传分析表明:8608S的不育性受一对隐性基因控制,且与农垦58S和培矮64S中的长日、高温不育基因存在非等位关系;该两用核不育系可降低长日、高温不育系的育性起点温度,对增强两系杂交稻田间制种安全性和提高杂种结实率有重大生产意义。     

12个水稻光温敏核不育系的ISSR标记鉴定及遗传分析

应用ISSR技术对12个水稻光温敏核不育系进行DNA指纹分析,筛选到13个生态性丰富的引物,共获得169个多态性DNA片段,选择其中的3个引物扩增出的8个多态性DNA片段可作为鉴定标记,能够正确区分供试的12个水稻光温敏核不育系。根据多态性片段的有无,将鉴定标记转换为数字1和0,建立了12个水稻光温敏核不育系相应的ISSR标记鉴定识别码。由Nei‘s,遗传距离创建的聚类分析表明,12个材料被聚为两大类群,4个梗型不育系聚为一类,其余8个籼型不育系聚为另一类,在籼稻群内,3个来源于安农S-1的不育系单独聚为一类,与来源于农垦58S的材料有明显的遗传差异。研究结果表明,ISSR标记具有简便、快速、多态性丰富等优点,可用于构建DNA指纹图谱,进行品种鉴定和遗传分析。     

淡绿叶色标记水稻光温敏核不育系开花习性

以4个淡绿叶粳稻光温敏核不育系和正常叶色粳型不育系浙农大11S(ZAU11S)及籼型不育系培矮64S(PA64S)共6个不育系为材料，在杭州自然条件下观察了上述6个光温敏核不育系的开花习性。结果表明：(1)淡绿叶色不育系同对照正常叶色不育系的叶色差异显著，易于肉眼分离；(2)淡绿叶色不育系的开花天数、开花率、柱头外露率都低于正常叶色不育系，日开花率、颖花张开时间和张开角度易受环境条件影响，表现较大差异；(3)除TS1外，其他三个淡绿叶色不育系在不育期和可育期的开花高峰都位于午前9：00或10：00，表现较强的早花特性。     

籼型光周期敏感核不育水稻的选育

1983~1985年以粳型光敏感核不育水稻农垦58为母本,98个早、中、晚籼稻品种为父本杂交育成了籼型光敏感核不育水稻1系(中稻类型)和2系(早稻类型)。在选育过程中,通过多做组合,扩大F₂代群体,严格鉴定选择等方法,克服了杂种后代分离大,有利变异少,籼粳杂交不育与核不育难以区分的困难,并在较低世代育成了稳定的矮稈籼型光敏感核不育水稻。实践证明,光敏感核不育基因可以导入籼稻和粳稻之中,其不育性与亲本的感光性无关,能独立遗传,只要在长日照下即能表达。     

不同氮肥水平下中熟籼稻和粳稻产量、氮素吸收利用差异及相互关系

选用生育期相近的中熟中籼(138~143 d)和中熟中粳(136~145 d),于大田条件下探讨了4种氮肥水平即0、150、225、300 kg hm^-2纯氮对产量的影响及不同生育阶段氮素吸收利用的差异。结果表明,随着氮肥施用量的增加粳稻平均产量呈增加趋势,而籼稻平均产量中氮水平达最高,高氮水平有所降低。各处理下籼稻产量明显高于粳稻,籼稻有较高的穗粒数和千粒重,平均分别比粳稻高22.45%、7.51%。植株氮素阶段吸收量,拔节、抽穗和成熟期籼稻平均分别比粳稻高24.26%、3.14%和6.45%;植株氮素阶段吸收速率,移栽至拔节、拔节至抽穗和抽穗至成熟阶段籼稻平均分别比粳稻高38.07%、16.05%和23.22%。相关分析表明,籽粒产量与氮素阶段吸收量、阶段吸收速率和氮肥利用率呈显著或极显著正相关关系。说明生育期相近的中熟中籼产量高于中熟中粳与籼稻植株较强的氮素吸收特性有关。     

Genetic analysis and fine mapping of tms9, a novel thermosensitive genic male‐sterile gene in rice (Oryza sativa L.)

Two‐line hybrid rice as a novel hybrid breeding method has huge potential for yield increasing and utilization of intersubspecific heterosis, and it is of major significance for the food security of rice‐consuming populations. Zhu1S is a thermosensitive genic male‐sterile line of rice with low critical temperature and excellent combining ability, which has been widely exploited as a female parent in Chinese two‐line hybrid rice breeding. Here, genetic mapping in F₂ populations was used to show that its male sterility is inherited as a single recessive gene and that responsible gene (termed tms9) lies on the short arm of chromosome 2. A high‐resolution linkage analysis which was based on the Zhu1S/R173 F₂ population found that the thermosensitive genic male‐sterile gene tms9 of Zhu1S was fine mapped between insertion–deletion (Indel) markers Indel 37 and Indel 57, and the genetic distance from the tms9 to the two markers was 0.12 and 0.31 cM, respectively. The physical distance between the two markers was about 107.2 kb. Sequence annotation databases showed that the two Indel markers (Indel 37 and Indel 57) were located on two BAC clones (B1307A11 and P0027A02). There are sixteen open reading frames (ORF) present in this region. The results of this study are of great significance for further cloning tms9 and molecular marker–assisted selection.     

Indica-japonica differentiation in Chinese rice landraces

Summary Ninety Chinese rice landraces were examined with special reference to the indica-japonica differentiation in terms of traditional criteria, isozyme analysis and PCR analysis of the chloroplast DNA (cpDNA). Cultivars were separated into indica and japonica defined by a discriminant function (Z) based on key characters, as well as by isozyme genotypes. Most indica landraces had chloroplast DNAs with a deletion at the Pst-12 fragment, while most japonica landraces had cpDNAs without the deletion. Two traditionally recognized varietal groups in China, keng and hsien, corresponded largely to the respective japonica and indica revealed in our study. The results obtained in this study showed good agreement for classification of indica and japonica types by the three methods: discriminant analysis by Z value, isozyme analysis, and PCR analysis for cpDNA.     

Fingerprinting temperate <Emphasis Type="Italic">japonica</Emphasis> and tropical <Emphasis Type="Italic">indica</Emphasis> rice genotypes by comparative analysis of DNA markers

This paper describes the relative efficiency of three marker systems, RAPD, ISSR, and AFLP, in terms of fingerprinting 14 rice genotypes consisting of seven temperatejaponica rice cultivars, three indica near-isogenic lines, three indica introgression lines, and one breeding line of japonica type adapted to high-altitude areas of the tropics with cold tolerance genes. Fourteen RAPD, 21 ISSR, and 8 AFLP primers could produce 970 loci, with the highest average number of loci (92.5) generated by AFLP. Although polymorphic bands in the genotypes were detected by all marker assays, the AFLP assay discriminated the genotypes effectively with a robust discriminating power (0.99), followed by ISSR (0.76) and RAPD (0.61). While significant polymorphism was detected among the genotypes of japonica and indica through analysis of molecular variance (AMOVA), relatively low polymorphism was detected within the genotypes of japonica rice cultivars. The correlation coefficients of similarity were significant for the three marker systems used, but only the AFLP assay effectively differentiated all tested rice lines. Fingerprinting of backcross-derived resistant progenies using ISSR and AFLP markers easily detected progenies having a maximum rate of recovery for the recurrent parent genome and suggested that our fingerprinting approach adopting the ‘undefined-element-amplifying’ DNA marker system is suitable for incorporating useful alleles from the indica donor genome into the genome of temperate japonica rice cultivars with the least impact of deleterious linkage drag.     

两系法杂交水稻制种不安全问题的解决途径

制种安全问题已严重制约两系法杂交水稻健康持续发展。水稻两用核不育系不育起点温度偏高、两系杂交稻制种基地和时段选择不当以及不育起点温度漂变是导致两系杂交稻制种不安全的主要原因。本研究表明,选育不育起点温度低和耐受低温时间长的水稻两用核不育系能降低制种风险;根据历史气象资料和两系杂交稻制种“三个安全期”对气象条件的要求,利用计算机技术,研制了两系杂交稻制种基地和时段气象决策支持系统,解决了以往生产上盲目选择两系杂交稻制种基地和时段的问题;研创了株系育性鉴定方法和一季加再生冷水串灌繁种技术,采用该方法生产原种能降低原种生产世代数,防止水稻两用核不育系不育起点温度漂变。通过以上研究可从种性、种源和制种地三方面提高两系法杂交水稻制种安全性。     

Developing gene-tagged molecular markers for functional analysis of starch-synthesizing genes in rice (Oryza sativa L.)

The granule-bound starch synthase(GBSS), starch branching enzymes 1 (SBE1)and 3 (SBE3) are major enzymes involved in starch biosynthesis in rice endosperm. Available sequences of Sbe1 and Sbe3 genes encoding corresponding SBE1 and SBE3 have been used to identify homologous regions from genome databases of both the indica rice 93-11 and the japonica rice Nipponbare. Sequence diversities were exploited to develop gene-tagged markers to distinguish an indica allele from a japonica allele for both Sbe1 and Sbe3 loci. With these newly developed gene-tagged markers and available Wx gene markers, the roles of these starch-synthesizing genes (Sbe1, Sbe3, and Wx) in determining amylose content (AC) in the rice endosperm were evaluated using a double-haploid (DH)population derived from a cross between the indica rice cv. Nanjing11 and the japonica rice cv. Balilla. Only the Wx and Sbe3 loci had significant effects on the AC variation. On average, indica Wx ^a genotypes showed ∼9.1% higher AC than japonica Wx ^b genotypes, while indica Sbe3 ^a genotypes showed ∼1.0% lower AC than japonica Sbe3 ^b genotypes. A significant interaction was also observed between Wx and Sbe3 loci whereby the amylose content was 0.3% higher in Sbe3 ^a than Sbe3 ^b genotypes in the presence of the Wx ^a allele, but it was lower by 2.3% in the presence of the Wx ^b allele. Overall, polymorphisms at the Wx and Sbe3 loci together could account for 79.1% of the observed AC variation in the DH population. The use of gene-tagged markers in marker-assisted selection and gene functional analysis was also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

杂交稻部分不育系与恢复系的SSR分类

选用分布于水稻(Oryza sativa L.)12条染色体上的36对SSR(simple sequence repeats)引物，分析了5个光温敏核不育系、7个细胞质雄性不育系及54份来自不同生态类型恢复系或品种的遗传差异。在供试材料中共检测出300条多态性片段，平均每对SSR引物检测到8.33条。分析结果表明，(1) SSR标记明确地把供试的66份水稻材料中的65份区分开来，和已知系谱的亲缘关系多数吻合，与表型性状聚类结果也有一定的相似性。(2) 以GD=0.73为标准，可准确地将籼稻、粳稻、野生稻三大类区分开；以GD=0.63为标准，又可区分出籼稻大类中带有粳稻或野生稻血缘的品种。表明SSR标记对籼稻、粳稻、野生稻品种的分类灵敏度高、结果可靠；并筛选出可用于鉴别水稻籼粳类型的10对特异性引物。(3) 以GD=0.56为标准，将供试材料划分在8个生态类型中，为生产上杂优组合亲本的选配提供了一些有益的参考。同时，生产上常用的一些杂交稻亲本划分在不同的生态类型中，表明强优势组合亲本间的遗传差异一般较大。     

光敏、温敏核不育水稻核不育基因等位性及基因对数的研究

以光敏核不育系农垦58S及其衍生的光敏核不育系7001S、温敏核不育系W6154S、增矮64S，以及温敏核不育系安农S－1及其衍生的温敏核不育系810S、安湘S、香125S为材料进行相互杂交，在长日高温条件下观察F1的育性，根据其可育性和不育性确定核不育基因的等位性。结果表明：7001S、W6154S、培矮64S与核不育基因供体农垦58S之间有等位点的核不育基因；但温敏核不育系W6154S与培矮64S之间，不具等位点的温敏核不育基因。该结果说明光敏核不育系农垦58S至少存在一对光敏核不育基因和两对温敏核不育基因，而且各对温敏核不育基因可独立遗传，在夏季高温条件下其不育性得到充分表达。安农S－1与其衍生的不育系之间以及衍生的不育系与不育系之间都具有等位点的温敏核不育基因。农垦58S及衍生的核不育系与安农S－1及衍生的核不育系之间没有等位点的核不育基因。     

Development of TGMS lines for developing two-line rice hybrids for the tropics

A breeding program was initiated at the International Rice Research Institute (IRRI) in 1990 to develop thermosensitive genic male sterile (TGMS) rice lines for developing two-line rice hybrids for the tropics. The TGMS trait was transferred from a temperate japonica TGMS mutant, Norin PL 12, to indica and tropical japonica rice varieties using the pedigree selection procedure. Six new TGMS rice lines adapted to tropical conditions were developed which showed complete pollen and spikelet sterility when maximum temperature was higher than 30 ^°C 1–2 week after panicle initiation. However, up to 85.5% spikelet fertility was observed when these lines were exposed to 26–29 ^°C during the critical stage. Using two of these TGMS lines, some heterotic rice hybrids showing 1–1.6 t/ha higher grain yield than the inbred check varieties were identified in unreplicated observational yield trial conducted at IRRI. Two of the six two-line hybrids yielded significantly higher than the check variety in a replicated preliminary yield trial. This revised version was published online in July 2006 with corrections to the Cover Date.