稻米胚重相关性状QTL分析

利用米粒胚重差异显著的广东早籼品种窄叶青8号（ZYQ8）和北方粳稻品种京系17（JX17），以及由它们构建的加倍单倍体（DH）群体127个株系，对糙米重、胚乳重、胚重和胚重率4个性状进行了评价与QTL分析。4个性状表现型均为连续分布，且都存在一定数量的双向超亲遗传类型，受多基因控制。共检测到13个影响4个性状的QTL，分布于     

水稻苗期耐淹相关性状QTL分析

以相同淹水条件下存活率差异较大的籼稻TN1与粳稻春江06(CJ06)为亲本构建的DH群体为试材,考察了DH群体及其双亲与苗期耐淹相关的5个性状,各性状均表现为连续分布,且都存在一定数量的双向超亲遗传类型,受多基因控制。使用分子连锁图谱进行QTL分析,共检测到16个与苗期耐淹有关的QTL,包括4个中胚轴长度QTL、3个株高QTL、3     

QTL analysis of seed storability in rice

A double haploid population, which consists of 127 lines derived from anther culture of a typical indica and japonica hybrid ‘ZYQ8’/‘JX17’, was used in this study. Seed storability was investigated by using the storage property measured by the difference of seed germination rates before and after treatment of the rice seeds under 40°C and 95% relative humidity for 10 days in a phytotron. Three QTLs related to rice seed storability were detected on chromosomes 9, 11 and 12, with the LOD scores 2.76, 4.83 and 2.54, respectively, together explaining 35.4% of the genetic variation. The ‘JX17’ allele at qLS‐9 and the ‘ZYQ8’ alleles at qLS‐11 and qLS‐12 could enhance the rice seed storability. The effects of the ‘ZYQ8’ alleles of qLS‐11 and qLS‐12 were also verified using chromosome segment substitution lines.     

水稻叶鞘相关性状的遗传分析

本研究以典型釉粳交(春江06/台中本地1号)的F1代花药加倍的DH群体为材料,系统考察了DH群体及其双亲在抽穗期的叶鞘长、叶鞘重、叶鞘厚等性状上的分布情况.结果表明,叶鞘长度的遗传力较高,受环境的影响相对较小,叶鞘长与叶鞘厚及叶鞘干重间大多呈极显著的正相关.QTL分析共检测到31个与叶鞘有关的QTL,分布于水稻第1、第...     

水稻萌发耐淹性种质资源筛选及QTL定位

萌发耐淹性种质资源的筛选、耐低氧萌发基因的挖掘和利用是选育适宜直播水稻新品种的基础。为简便、高效的评价种质资源的萌发耐淹性,本研究对来自不同年代和地区的191份粳稻种质资源进行了萌发耐淹性鉴定,共获得12份萌发耐淹性强的种质资源,其中连粳15号表现出较强的低氧萌发能力。利用其与籼稻品种黄莉占构建的F2:3分离群体,采用模拟大田的鉴定方法,在水稻1号、3号、9号、10号染色体上共检测到4个QTL,即qGS1、qGS3、qGS9和qGS10。共解释表型变异的70.9%,其中qGS1、qGS3和qGS10,能够被重复检测到,贡献率分别为19.2%~24.0%、12.6%~14.7%、19.1%~20.5%,是稳定表达的QTL位点。这些种质资源和QTL的发现为耐低氧发芽水稻新品种的培育提供了重要的亲本资源、基因资源和标记资源,同时也为选育优良直播稻品种提供了理论依据。     

Identification of quantitative trait loci (QTLs) for the characters of vascular bundles in peduncle related to indica-japonica differentiation in rice (Oryza sativa L.)

The number of vascular bundles in peduncle and the ratio of vascular bundles to primary rachis branches (V/R ratio)distinguishable between indica andjaponica, are the traits associated with the processes of differentiation between indica and japonica inrice (Oryza sativa L.). In this paper a doubled-haploid population derived from the F₁ hybrid of a cross between anindica cultivar and a japonicacultivar was used to map quantitative trait loci(QTLs) controlling numbers of vascular bundles in peduncle, primary rachis branches and the V/R ratio. For vascular bundles, three QTLs were detected and they collectively explained 58.8% of the total variation. Among them, the QTLqVB-8 with the largest effect,located on chromosome 8, individually accounted for 31.1% of the total variation. Two QTLs controlling primary rachis branches, located on chromosome 8and 10 respectively, were identified and they individually explained 10.5% and18.0% of the total variation respectively. Three QTLs for the V/R ratio, mapped on chromosome 1, 2 and 8, respectively,jointly explained 61.3% of the total variation. Of the three QTLs, the QTL qV/R-1 with the largest additive effect,explained 25.3% of the total variation,was located on chromosome 1 and found to be closely linked to the gene sh-2, a major gene underlying grain-shattering ability. In addition, four and two pairs of significant epistatic QTLs were detected for vascular bundles and the V/R ratio,respectively, but none for rachis branches. Our results suggested that the numbers of vascular bundles and primary rachis branches were independently controlled by different polygenic systems, but the two polygenic systems shared a fraction of quantitative trait loci. The present study also demonstrated that the chromosome region carrying the QTL qV/R-1 for the V/R ratio and the gene sh-2 might play an important role in the processes ofindica-japonica differentiation in rice (Oryza sativa L.). This revised version was published online in August 2006 with corrections to the Cover Date.     

水稻萌发耐淹性种质资源筛选及QTL定位

作者用水培的方法研究水稻不同生育期缺磷的影响,结果证明：幼苗期缺磷的影响最显著,表现出生长缓慢,分蘖减少。因此,栽培水稻在幼苗期及分蘖期充分供应磷肥有特别重要意义。     

Detection and validation of QTLs associated with seed longevity in rice (Oryza sativa L.)

Seed longevity in rice is a major determinant in seed production and germplasm preservation. In this paper, a recombinant inbred line (RIL) population consisting of 172 lines derived from the cross between Xiang743 and ‘Katy’ was used to map quantitative trait loci (QTLs) for seed longevity (SL) after seed storage for 18 and 30 months under ambient conditions. Two putative QTLs, qSL‐2 and qSL‐8, were detected and located on chromosomes 2 and 8, respectively. qSL‐2 is an allele from Xiang743 allele and increases seed longevity. qSL‐8 was a novel QTL from ‘Katy’ allele and increases seed longevity. qSL‐8 explained 15.29% and 17.35% of the phenotypic variance after seed storage for 18 and 30 months, respectively. Furthermore, qSL‐8 was validated in a secondary population developed by self‐pollination of a residual heterozygous line (RHL) selected from the RIL population, which explained 25.93% of the phenotypic contribution. These results provide an opportunity for map‐based cloning of qSL‐8. Furthermore, qSL‐8 may be a target for improving seed longevity by marker‐assisted selection (MAS) in rice.     

水稻耐低磷胁迫研究进展

土壤中有效磷缺乏是制约水稻生产的主要因素之一。利用磷效率不同的水稻基因型选育磷高效水稻品种,是解决水稻磷营养问题的一种更为经济、环保的途径。本文简要论述了水稻耐低磷胁迫的机理及磷高效基因型筛选体系,重点综述了近年来水稻磷效率相关性状的QTL定位分析结果,以期为水稻耐低磷研究及磷高效水稻品种的选育提供参考。     

Genetic analysis of ratooning ability of rice (Oryza sativa L.)

Summary Genetic analysis of generation means of F₁, F₂, F₃, F₄, and the parental populations of the cross IR10154-23-3-3A/IR15795-232-3-3-2 for ratooning ability was conducted. Good ratooning ability is a recessive trait. The parents differed by at least two pairs of major genes for ratooning ability. A large proportion of transgressive segregants in F₂ suggested that the expression of ratooning ability is influenced not only by major genes but also by modifiers. Broad-sense heritability estimates computed by different methods ranged from 0.66 to 0.88. Narrow-sense heritability by the F₄–F₃ regression method was 0.39. The heritability estimates were 0.42 and 0.33 by the variance component method. The prevalence of additive x additive type of gene effects along with prominent additive effects imply some scope for selection in the segregating generations. However, non-additive type of gene action also affects the expression of ratooning ability.     

水稻圆粒基因RS的鉴定和定位

阐明水稻籽粒大小相关基因的遗传和分子机制对水稻产量形成具有重要意义。利用甲基磺酸乙酯(ethyl methanesulfonate, EMS)诱变粳稻品种宁粳3号筛选获得圆粒突变体round seed (rs)。遗传分析表明,突变体rs圆粒表型由单隐性核基因控制。颖壳扫描电镜观察发现,rs籽粒变圆主要是细胞数目改变导致的。在突变体rs中,细胞周期相关基因的表达较野生型显著升高。将RS定位在第3染色体短臂标记RM3413与N3-5之间,物理距离约589 kb。RS突变影响BR信号途径,改变了粒型相关基因的表达。本研究有助于阐明水稻籽粒发育的分子机制。     

Mapping of quantitative trait loci controlling seed longevity of rice (Oryza sativa L.) after various periods of seed storage

Seed longevity varies considerably in cultivated rice (Oryza sativa L.), but the underlying genetic mechanism of longevity has not been well elucidated. Quantitative trait loci (QTL) that control seed longevity after various periods of seed storage were sought using recombinant inbred lines derived from a combination involving ‘Milyang23’(Indica‐type) and ‘Akihikari’ (Japonica‐type). In all, 12 QTLs for germination and normal seedling growth were detected as indices of seed longevity on chromosome 7 (one region) and chromosome 9 (two regions) in treated seeds that had been stored under laboratory conditions for 1, 2 or 3 years.‘Milyang23’ alleles of all QTLs promoted germination and normal seedling growth after all durations of storage. These QTL regions were detected repeatedly in more than one seed condition. Therefore, we infer that these regions control seed longevity.     

Genetics of stem elongation ability in rice (Oryza sativa L.)

Summary The genetics of stem elongation ability in rice was studied in parents, F₁, F₂ and backcross generations of six crosses. Segregation analysis indicated dominance for stem elongation ability. Estimation of genetic parameters under epistatic model indicated more than one locus control stem elongation ability and both additive and nonadditive gene effects were important. Epistatic effects were predominant over additive and dominance effects with an important role of duplicate type of epistasis. The occurrence of significant additive and additive x additive types of genetic variation and the moderately high broad sense heritability indicated the possibility of selection for an increased manifestation of stem elongation ability.     

Trisomic genetic analysis of aroma in three Japanese native rice varieties (Oryza sativa L.)

Information on the genetics of aroma in rice facilitates breeding and selection of new aromatic varieties with high yield and good quality. Objective of the present study was to make clear the number of genes controlling aroma, and the allelism of aroma genes and the location of aroma gene(s) on the chromosome in three Japanese native aromatic rice varieties (Kabashiko, Shiroikichi and Henroyori). Lack of leaf aroma in all F₁ plants of non-aromatic/aromatic crosses indicated the recessive nature of aroma, and the segregation ratios (3:1) of non-aromatic to aromatic plants in its F₂ populations from Nipponbare/aromatic varieties crosses revealed that each of the three aromatic varieties contains a single recessive gene for aroma. Through trisomic analysis, the segregation of non-aromatic and aromatic plants in all F₂ populations from the crosses between trisomics lines NT8, with an extra chromosome 8, and aromatic varieties deviated significantly from disomic segregation of 3:1 ratios, and fitted to trisomic segregation, however, in other F₂ populations derived from other 7 types of trisomic F₁ plants, the segregation ratios of non-aromatic to aromatic were 3:1, indicating that the single recessive aroma gene was located on chromosome 8 in three aromatic varieties. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mapping of quantitative trait loci associated with rice black‐streaked dwarf virus disease and its insect vector in rice (Oryza sativa L.)

Rice black‐streaked dwarf virus disease (RBSDVD), transmitted by small brown planthopper (SBPH, Laodelphax striatellus), causes serious loss in rice production. Breeding resistant cultivars are one of the most effective strategies to control the virus disease and its vector. By both natural inoculations in the field and modified seedling‐box screening test in the glasshouse, an indica variety WR24 showed high resistance to RBSDVD and SBPH. An F_2:3 population consisting of 153 lines derived from a cross between WR24 and a susceptible japonica variety Suyunuo was used for quantitative trait loci (QTL) analysis of RBSDVD and SBPH resistance. The linkage map consisting of 130 SSR markers was constructed with an average marker interval of 13.90 cM, spanning a total of 1890.9 cM. Totally, five QTLs for RBSDV resistance, viz. qRBSDV3^WR24, qRBSDV6^WR24, qRBSDV7^WR24, qRBSDV9^WR24 and qRBSDV11^WR24, were detected on chromosomes 3, 6, 7, 9 and 11, with LOD scores of 2.7, 3.08, 3.13, 5.28 and 3.7, respectively. Meanwhile, three QTLs for SBPH resistance, including qSBPH5^WR24, qSBPH7^WR24 and qSBPH10^WR24, were mapped on chromosomes 5, 7 and 10, with LOD scores of 2.18, 3.5 and 3.57, respectively. All resistant alleles were from WR24. Among these QTLs, qRBSDV7^WR24, qSBPH5^WR24 and qSBPH10^WR24 were newly reported, and qSBPH10^WR24 showed major effect that explained 17.9% of total phenotypic variance. The RBSDVD and SBPH resistance QTLs and the tightly linked DNA markers can be utilized in RBSDV and SBPH resistance breeding in rice.     

QTL analysis for resistance to preharvest sprouting in rice (Oryza sativa)

Preharvest sprouting (PHS) is caused by early breaking of seed dormancy. In Sichuan, a major hybrid rice seed production area of China, PHS in hybrid seeds originated from ‘G46A’ parent may lead to severe yield loss, causing serious damage to agricultural production. To detect quantitative trait loci (QTLs) governing PHS, we developed an F₂ population of 164 plants derived from ‘G46B’ and ‘K81’, a near‐isogenic introgression line of G46B, with high level of resistance to PHS. PHS was evaluated under controlled field and laboratory conditions. Using simple sequence repeat markers, we constructed a linkage map from this population and identified three QTLs for PHS, namely qPSR2, qPSR5 and qPSR8, which were located on chromosomes 2, 5 and 8, respectively. Among these QTLs, qPSR8, residing in the interval between RM447 and RM3754 on chromosome 8, was the major QTL controlling PHS, for it had a relative high logarithm of the odds (LOD) score and explained 43.04% of the phenotypic variation. These results were correspondent to those identified in extreme low germination rate plants (ELGP) using linkage and linkage disequilibrium. At all loci, ‘K81’ was responsible for enhancing the resistance to PHS.     

水稻苗期耐Cd胁迫的QTL定位分析

[目的]进行水稻苗期耐Cd胁迫的QTL初步定位。[方法]（1）以Lemont（美国）和Dular（印度）杂交建立的重组自交系（RILs）群体,包括123个家系和亲本在内,用含有0.2mg/L镉的水培液进行处理,以不加镉培养的水培液作为对照,考察了叶绿素含量、根长、株高、叶长等4个性状,并转换成抗性指数,用于评价水稻对Cd污染的抗性指标。（2）在已构建的以109个引物为基础的遗传图谱上进行复合区间定位。[结果]（1）共检测到9个加性QTLs,涉及1,2,3,11等4条染色体,其中,以叶绿素抗性指数为指标,检测到3个与耐Cd有关的QTLs 分别位于第2,3,11染色体上,解释了14%,9%,9%的表型变异;（2）以根长抗性指数为评价指标,只定到1个位于第1染色体上控制耐Cd的QTLs,解释了9%的表型变异; （3）用株高抗性指数进行定位,共有3个与耐Cd相关的QTLs,位于1,1,11染色体上,分别解释了10%,27%,10%的表型变异;（4）而以叶长抗性指数进行水稻秧苗耐Cd性表现的QTL定位,结果发现也有2个QTLs与其耐Cd 反应有关,它们分别位于1,11染色体上,解释了21%,12%的表型变异。分析表明,在采用不同评价指标所检测到的9个与耐Cd相关的QTLs中,有7个集中于第1和第11染色体上,其中第1染色体上有4个,第11染色体上有3个。（结论）以株高和叶绿素抗性指数为评价指标,检测到的QTLs最多,根长抗性指数为评价指标的最少。研究还发现在第1和第11染色体上的相同区间内同时检测到以不同抗性指数为评价指标的多个与耐Cd相关的QTLs,推测它们可能是功能相同的几个紧密连锁的非等位基因,也可能就是同一等位基因的不同表现形式,从而也说明了该评价指标用于基因定位的准确性和可行性。     

Anther and pollen grain culture of rice (Oryza sativa L.)

Summary Factors favouring callus proliferation and subsequent regeneration of plants from pollen grains of rice anthers (Oryza sativa L., cvx. Bahia, Girona, Balilla × Sollana and Sequial) were determined. Cultivar differences in response were found, such as a high rate of haploid plant regeneration.In addition, isolated pollen grain culture was used to induce tissue proliferation outside the anther walls. The frequency of callus formation from isolated pollen grains was very low. It was necessary to preculture the anthers before pollen grain separation, in order to accomplish a successful development later. Root differentiation was observed in some of the obtained callus.