北方杂交粳稻亲本遗传背景分析

 为了揭示北方杂交粳稻亲本的遗传背景，利用微卫星(SSR)分子标记对北方杂交粳稻亲本及其高代后续材料进行了遗传差异鉴定和籼性程度分析。26对SSR引物共扩增出71个等位基因，每对引物平均等位基因数为2.73个。用非加权类平均法(UPGMA)进行聚类分析，供试材料在相似系数0.66处可分成5组，各组间材料的遗传差异相对较大；64个恢复系材料的籼性程度参数值(ADi)的变幅为0.056～0.684；24个不育系材料ADi的变幅为0.087～0.381。分析表明，强优势杂交粳稻组合双亲之间遗传距离应在0.30～0.60，恢复系的ADi应在0.26～0.50，不育系的ADi不应高于0.20，杂交组合的ADi应在0.20～0.40，同时杂交粳稻组合优势受母本的遗传背景的影响较大，母本自身应具有较高的产量潜力。     

我国常规稻主栽品种的遗传变异分析

 采用40个SSR标记，分析了329份我国近50年来常规稻主栽品种的遗传变异。结果显示，39个SSR标记具有多态性，在多态性位点共检测到223个等位基因，每个位点2～11个，平均57个；平均Nei基因多样性指数（He）为0632。籼粳亚种间的SSR变异差异明显，籼稻平均等位基因数（Na）和Nei基因多样性指数（Na = 54，He = 0440）均高于粳稻品种（Na = 44，He = 0397）。Nei遗传相似系数表明总体样本具有较小的遗传相似度（I = 0366），而骨干亲本具有较高的遗传相似度（籼:I = 0590；粳:I = 0590）。这导致了籼粳亚种内较高的遗传一致性（籼:I = 0558；粳:I = 0600）。早、中、晚稻各类型遗传相似度差异明显，晚籼和早粳类型具有较高的遗传变异。籼粳稻品种尤其是粳稻的聚类结果显示出较强的季节型和地域特征。这些均提示育种家应选择更广泛的亲本源以拓宽选育品种的遗传基础。     

采用SSR标记和表型性状聚类对杂交粳稻亲本的遗传多样性研究

以20个新育成的粳稻BT型不育系和10个恢复系为材料,采用SSR分子标记和表型性状2种聚类方法对杂交粳稻亲本的遗传多样性进行比较研究,并分析这些亲本的遗传差异.结果表明,64对SSR引物在30个亲本中共检测到185个多态性片段,平均每对引物为2.9个,以第11染色体上的平均等位基因数目最多,每个SSR位点的多态性信息含量指数(PIC值)变化范围为0.064～0.844.利用SSR分子标记将30个亲本材料划分为7大类群,其中所有不育系被划分为一群,分类结果与系谱分析基本吻合.表型聚类以10个农艺性状为依据,将供试材料划分为4大类群,不育系和恢复系被聚到不同的类群,群内差异小大.同表型性状聚类相比,SSR分子标记聚类能更准确的揭示亲本之间的遗传差异,是研究亲本遗传多样性的一种较好方法.     

SSR标记遗传距离与粳稻杂种优势的相关性分析

 利用SSR分子标记对30个粳稻品种进行遗传多样性分析，继而研究分子标记遗传距离与按照NCⅡ设计获得的200个杂交组合主要产量性状杂种优势的相关性，探讨分子标记遗传距离预测杂种优势的可行性。结果表明，64对SSR引物共检测到185条多态性片段，平均每对引物2.9条，每个SSR位点的多态性信息含量指数（PIC值）变化范围为0.064~0.844，平均为0.380。以SSR标记遗传相似系数为原始数据，按UPGMA聚类方法将30个亲本材料划分为7大类群，分类结果与系谱关系基本相符。分子标记遗传距离与杂种性状平均值的相关除每穗总粒数外均达到显著或极显著水平，与杂种优势的相关均达到极显著水平，相关系数介于-0.361~0.359，说明分子标记可用于水稻杂种优势群的划分和遗传多样性分析，但相关程度还不足以预测产量杂种优势。     

基于SSR标记的中籼型两系杂交水稻亲本遗传差异分析

利用48对SSR引物对50份中籼型两系杂交水稻骨干亲本或改良系进行了遗传多样性分析。结果表明,基于SSR分子标记的遗传聚类结果与供试材料的系谱关系高度一致,不育系和恢复系明显聚类为2个群组(Ⅰ和Ⅱ),2个群组内的平均遗传距离差异不明显。湖南隆平高科种业科学研究院有限公司选育的多数不育系材料聚合为不育系群组下的一个单独亚组(Ⅰ-4),且在4个不育系亚组中具有最大的组内平均遗传距离。华占衍生系和广东常规稻独立于9311衍生系或近缘系,且已明显分化为2个亚组(Ⅱ-2和Ⅱ-3)。华占衍生系或近缘系组存在一定程度的同质化问题,为进一步拓展此群组与湖南隆平高科种业科学研究院有限公司不育系群组之间的遗传距离,提高群组间的杂种优势水平,需继续引入华南优质、高抗、广适种质进行改良。     

小麦亲本间分子遗传距离与F1杂种优势的相关性分析

为了探讨利用小麦亲本间分子遗传距离预测F1杂种优势的可行性，以河南省8个不同类型的小麦品种（系）为材料，分别于2003年和2004年按不完全双列杂交组配28个组合，分析与产量相关的9个性状的F1杂种优势。分别选用均匀分布于小麦21条染色体上的287对SSR引物和33个二核苷酸重复ISSR引物，计算8个亲本间的分子遗传距离．进而分析亲本间分子遗传距离与F1杂种优势表现的相关性。结果表明，SSR和ISSR两种标记估算的遗传距离间相关极显著（相关系数为0．832），表明用两种分子标记对小麦品种进行遗传差异分析的结果是一致的。除株高外，利用两种分子标记计算的亲本间分子遗传距离与F1杂种优势在全部28个组合中相关不显著，而在12个极端组合中相关系数得到较大提高，并在株高、主茎千粒重和千粒重3个性状上相关达到显著或极显著水平，且两年的研究结果一致。这说明亲本间分子遗传距离与F1杂种优势的相关性与材料的选择有关。因此认为利用小麦亲本间的SSR和ISSR遗传距离预测F1的杂种优势还需进一步研究。     

玉米分子遗传图谱的构建

以R15(抗)和Ye478(感)为亲本配制F2分离群体并以该群体为作图群体。利用778对SSR引物对亲本R15、Ye478之间的多态性进行了检测,筛选出159对多态性SSR引物用于F2群体分析。利用这159对(20.4%)多态性标记构建玉米的遗传连锁图谱,其中有9个SSR标记没连锁上。其余150个标记分布于玉米的10条染色体上,覆盖玉米基因组1775.7cM,标记间平均距离为11.8cM。     

33个育成花生品种遗传多样性分析

利用75对SSR标记引物对33个育成花生品种进行遗传多样性分析,结果表明,其中有10对标记引物扩增出多态性,共检测到33个多态等位点,每对引物分别检测出4～8个等位点变异,平均为6.0个,33个花生品种间的遗传相似系数在0.242～1.000之间,平均为0.621。聚类分析结果表明33个参试花生品种在遗传相似系数0.600处分为2个类群,亲本来源相近的品种优先聚在一起。     

利用SRAP和SSR标记构建红麻遗传连锁图谱

构建红麻遗传连锁图谱,为今后红麻重要农艺性状QTL定位、QTL图位克隆、优良基因筛选、分子标记辅助育种奠定良好的研究基础。对256对SRAP引物和64对棉花SSR引物进行了两次引物筛选,以泰红763×F71为作图群体亲本,150个F2代单株作为作图群体,构建红麻遗传连锁图谱。共筛选出条带清晰、多态性高的SRAP引物73对、SSR引物8对,构建的红麻遗传连锁图谱全长2155.43 c M,平均间距为16.09 c M,含有128个多态性标记,分布于18个连锁群。本研究初步证实了棉花SSR引物用于红麻是可行的,构建的红麻遗传连锁图谱密度较高,标记较为均匀,适合后续的QTL定位、QTL图位克隆等研究工作。     

郑58和掖478玉米自交系基因组差异性分析

采用SSR标记对我国核心种质郑58和掖478进行基因组差异性分析。结果表明:200对引物中有57对引物具有多态性,多态性标记比率达到28.5%,遗传相似度为71.5%。200对引物共计扩增出424个SSR等位性片段,其中有113个多态性等位片段,遗传杂合度为26.7%,遗传相似度为74.3%。SSR多态性标记在不同染色体上呈现不均匀性分布,在同一染色体上不同区域分布密度不同,具有多态性标记集中区域,基因组差异可能与自交系配合力变化有关。     

Genetic Diversity and Allelic Frequency of Selected Thai and Exotic Rice Germplasm Using SSR Markers

A collection of 167 Thai and exotic rice accessions was subjected for evaluation of genetic diversity and assessment of relationship by simple sequence repeat(SSR) markers. Among a total of 49 SSR markers, 13 markers distributing over 12 rice chromosomes showed clear polymorphic band patterns, and they were selected for genetic assessment. A total of 110 alleles were detected with an average of 8.46 alleles per locus. The averages of gene diversity, heterozygosity and polymorphic information content were 0.59, 0.02 and 0.56, respectively. The unweighted-pair group method with arithmetic averages(UPGMA) clustering analysis was performed for genetic distance, and phylogenetic tree was constructed. The result showed that this rice collection was divided into two major groups, classified as japonica and indica subspecies. Within the japonica group, temperate japonica and tropical japonica subgroups can be clearly separated. Three-dimensional principal component analysis projection and model-based population structure analysis showed consistent clustering results with two major groups of UPGMA analysis, supporting the classification of japonica and indica subspecies. The indica allelic frequency was also investigated to provide an indicative guide for breeders to overcome the practical problems on sterility of inter-subspecies hybrid offspring. This rice collection and information obtained in this study will be useful for rice breeding programs.     

Genetic Structure and Indica/Japonica Component Changes in Major Inbred Rice Varieties in China

We used 39 SSR markers to analyze the genetic structure of 304 major Chinese inbred rice varieties, and to compare changes in the indica or japonica components in these varieties that have been widely cultivated from the 1950s to the 1990s in China. The genetic structure analysis showed that these rice varieties were distinctly divided into two populations, indica and japonica. The sub-structure of indica varieties was more complex than that of japonica ones. Among the various lines, late-season indica and early season japonica varieties had simpler genetic backgrounds. The seasonal ecotypes were not quite consistent with the subtypes of genetic structure. Twelve SSR loci with specific differentiation between indica and japonica were used to calculate the indica/japonica components. The differences in indica/japonica components among the five decades were not significant, except for late-season indica varieties in the 1990s, which had a significantly higher japonica component. These results will help to understand the genetic structure of the major Chinese inbred rice varieties and will be useful for indica-japonica hybrid breeding in China.     

北方杂交粳稻亲本籼粳成分与杂种产量和稻米品质性状的关系

以北方杂交粳稻骨干亲本及其组合为材料,采用程氏指数法和微卫星分子标记法,对亲本籼粳成分与杂种产量和稻米品质性状的关系进行了研究。杂交粳稻骨干亲本的程氏指数为13.5～19.3,偏籼系数为0.12～0.38,采用程氏指数和分子标记法对亲本进行籼粳分类的结果并不完全一致。父本程氏指数与产量杂种优势和杂种性状的相关性强于母本,而对于偏籼系数则相反。亲本程氏指数差异与产量杂种优势和杂种性状的相关性强于分子标记差异。亲本籼粳成分及其差异与多数杂种性状和产量杂种优势呈明显的二次曲线关系,存在临界极值;亲本籼粳成分及其差异与杂种产量性状和稻米品质性状的相关性相反。因此,要获得产量杂种优势和杂种表现最佳、高产与优质相结合,父母本籼粳成分应适度搭配。     

Genetic Diversity of Rice Landraces from Lowland and Upland Accessions of China

Genetic diversity of rice landraces from lowland and upland accessions of China was investigated using 66 polymorphic simple sequence repeat (SSR) markers.The total number of alleles detected from all 324 tested accessions was 555 with an average allele number (Na) of 8.409 per locus,the average effective number of alleles (Ne) of 3.574 and the average Shannon’s information index (I) of 1.378.The genetic diversity was higher for the indica landraces compared to the japonica landraces,and the upland landraces were more genetically diverse than the lowland landraces.The SSR markers,RM72,RM232,RM219,RM241,RM224 and RM3 showed the highest rates of polymorphism and these SSR markers were suitable to assess the genetic diversity of rice germplasm resources.A dendrogram of 324 accessions of lowland and upland landraces showed that all rice accessions were mainly subdivided into two groups,japonica and indica,with some being intermediate.The distribution of lowland and upland landraces among the japonica and indica rice groups was distinct,with obvious differentiation between the lowland and upland landraces in japonica rice,but no such clear distinction in indica rice.     

籼粳稻杂交后代群体形态分化与遗传分化的比较

 以典型籼稻七山占和典型粳稻秋光构建的F8、F9重组自交系为试材，研究表型性状所揭示的形态分化与籼粳特异SSR标记所揭示的遗传分化差异，探讨维管束性状与形态分化和遗传分化的关系。形态分化和遗传分化所揭示的群体后代籼粳属性均呈偏粳分布，遗传分化所揭示的更加偏粳。依程氏指数、大小维管束比、大维管束比的分类结果与遗传分化相符度均为50%左右，将维管束性状作为程氏指数补充所得总分值与遗传分化的相符度为80%左右，相符度显著增高。维管束数量比可以作为籼粳分类的补充性状。     

利用微卫星标记比较云南元阳哈尼梯田两个不同时期种植的水稻地方品种的遗传多样性

 为了揭示云南元阳哈尼梯田两个不同时期种植的水稻地方品种的遗传多样性，以元阳哈尼梯田过去种植（20世纪70年代收集于元阳县，现保存于种质库）的72个和当前种植的76个品种为材料，采用48个SSR分子标记进行多态性、遗传相似性和聚类分析。平均每个标记检测到的等位基因数、有效等位基因数、位点多态信息含量和基因型多样性指标在过去与当前的品种间，差异均未达显著水平。共有24个SSR标记的52个等位基因位点在过去与当前种植的品种中存在差异，其中，有18个SSR标记的32个等位基因位点在当前的品种中未检测到，同样，有16个SSR标记的20个等位基因位点在过去的品种中未检测到。基于48个SSR分子标记的平均遗传相似性系数，当前种植的品种为03340，过去为03313，过去与当前的品种分别在遗传相似性系数0203和0174处分为籼、粳两个亚种群。表明元阳哈尼梯田水稻地方品种经过30多年的自然与人工选择，虽有部分等位基因位点发生了变异，但仍保留了原有的遗传多样性；元阳哈尼梯田水稻地方品种存在明显的籼、粳分化。元阳哈尼梯田及其水稻地方品种是研究稻作籼粳演化的理想基地和材料。     

中国常规稻主栽品种的遗传结构及籼粳组分变化

 采用SSR标记分析了304份我国20世纪50-90年代生产上广泛应用的常规稻主栽品种的遗传结构及不同时期籼粳组分的变化。结果显示，我国常规稻主栽品种可明显分为籼、粳两类，籼稻的亚遗传结构比粳稻更为复杂，但晚籼和早粳类型的遗传背景略为单一。早、中、晚各季节类型与遗传结构的分型结果符合度较低。利用12个籼粳分化特异的SSR位点分析各品种的籼粳组分，发现20世纪90年代晚籼类型的粳型组分明显增加，而其他类型不同时期间籼粳组分的差异较小。研究结果对了解我国常规稻品种的遗传结构以及籼粳交育种具有一定的意义。     

Comparison of Morphological and Genetic Differentiations in Filial Generation of Cross Between Indica and Japonica Rice

A recombinant inbred line (RIL) population of F8 and F9 generations derived from a cross between a typical indica rice (Qishanzhan) and a typical japonica rice (Akihikari) was used to study the difference between morphological differentiation based on phenotype characters and genetic differentiation using indica and japonica specific SSR markers, and to evaluate the relationship between vascular bundle characters and morphological and genetic differentiations. The results showed that the frequency distributions of morphological and genetic differentiations were all inclined to japonica type in the filial generation. The population was more inclined to japonica type based on genetic differentiation than on morphological differentiation. The consistent degrees of classification based on the Cheng's index, the ratio of large vascular bundle number to small vascular bundle number in panicle neck (RLSVB) and the ratio of large vascular bundle number in the second internode from the top to that in the panicle neck (RLVB) were all about 50% compared with the genetic differentiation, and the consistent degree of the total scores of the Cheng's index combined with the vascular bundle number ratios was significantly increased to about 80% compared with the genetic differentiation. Therefore, the vascular bundle characters could be used as a helpful supplement for subspecies classification.     

滇型杂交粳稻主要亲本的SSR 指纹图谱及其遗传差异分析

用筛选的13对SSR引物,构建了41个水稻品种(包括35份滇型杂交粳稻恢复系、保持系材料、2个杂交种以及4个籼稻品系)的分子指纹图谱.聚类分析表明,41个水稻品种间遗传相似系数在0.52～0.94之间;在相似系数0.52处,可以将粳稻与籼稻区分开;在相似系数0.66处,可将杂交粳稻与其它粳稻品系区分开;在相似系数0.71处,又可将大部分恢复系与保持系区分开.生产中应用的一些强优势滇型杂交粳稻的亲本分别聚于不同的类群,表明亲本间的遗传差异较大.