分子标记遗传效应预测杂交水稻产量性状

选用13个水稻不育系和19个恢复系按NCⅡ设计配制两套不完全双列杂交组合151个,2005年分别在重庆和泸州种植,结合AFLP和SSR标记位点的遗传效应,预测7个产量性状值。用两套组合F1产量性状对标记多态性位点进行筛选,获得阳性位点和增效位点及其加性和(或)显性效应值,通过逐步回归构建分子标记遗传效应预测产量性状模型,并对不同亲本组合(套间预测)及固定亲本组合产量性状进行了预测。结果表明:(1)阳性和增效位点进行套间预测的效果,绝大多数不理想(预测值与实际值的相关系数为-0.55~0.45),且预测效果不稳定;(2)阳性和增效位点对第二套固定亲本组合的预测效果相近,均优于套间预测,其中对固定恢复系组合的预测好于对固定不育系;(3)对固定亲本组合大部分产量性状的预测达到较理想水平,其中增效位点对固定不育系组合结实率、固定恢复系组合有效穗数、阳性位点对固定恢复系组合穗着粒数、单穗重的预测在0.6以上。用分子标记遗传效应预测产量性状,只需少数标记,应用方便,特别是对水稻育种亲本选配具有重要指导意义。     

杂交水稻产量性状配合力研究

利用 9个不育系和 7个恢复系配制 40个杂交组合 ,对 6个产量性状的亲本一般配合力和组合特殊配合力效应进行分析。结果表明 ,杂种一代 (F1)各性状的形成同时受亲本一般配合力和组合特殊配合力的影响。单株穗数、每穗总粒数、千粒重三性状主要受一般配合力作用 ;每穗实粒数、结实率、单株粒重三性状则一般配合力和组合特殊配合力的作用同样明显 ,或特殊配合力作用更明显些。不育系珍汕 97A、龙特浦A、K1 8A和恢复系明恢 63、直龙、1 0 2 5的一般配合力高 ,利用它们容易配制出高产组合。两年试验结果千粒重、单株粒重二性状的形成均是不育系的作用大于恢复系 ,近期育种工作重点应放在不育系的选育上。     

杂交稻特殊配合力与杂种优势、亲本间遗传距离的相 关性

杂交水稻育种的实质是配合力育种, 筛选高特殊配合力的杂交水稻组合才能选育出在生产上有实用价值的强优势组合。文章利用SSR标记检测了9个三系杂交稻亲本(5个不育系和4个恢复系)之间的遗传距离, 结合20个杂交稻组合(5×4 NCII)的产量表现, 分析了杂交水稻特殊配合力(Special combining ability, SCA)效应与产量杂种优势、亲本间遗传距离的相关性。结果表明, 特殊配合力效应与对照优势(相关系数r₁=0.5609)、平均优势(相关系数_r2=0.541)之间均呈显著正相关, 而与亲本遗传距离之间相关不显著, 相关系数(r=0.2143)较小。说明本研究所配组合的特殊配合力效应能充分反映杂种优势, 选用的杂交亲本能组配出强优势组合; 而杂交亲本遗传距离的大小并不能反映特殊配合力效应, 分子标记遗传距离与特殊配合力的相关性还有待于进一步的探讨。     

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）。     

33份杂交稻亲本的SSR指纹图谱构建及遗传相似性分析

选用分布在12条染色体上84对SSR引物,对6个粳型和4个籼型核质互作雄性不育系、14个籼型和9个粳型父本,共33份杂交稻亲本材料进行遗传相似性分析,并建立SSR指纹图谱数据库.结果表明:在33份材料中能够扩增出多态性的引物有54对,占所用引物的64.3％;33 份材料间遗传相似系数变异范围为0.429～0.988,在遗传相似系数0,65处,33份材料被聚为籼、粳2个大类群;利用14对引物能将33份材料区分,引物RM264能将‘Ⅱ-32A'、‘协青早A'、‘冈46A’和‘K17A'4个籼型不育系与籼型恢复系区分开,引物RM432能区别5个粳型不育系与粳型可育品种,引物RM6、RM13、RM16、RM240、RM247和RM248均能鉴别籼、粳亚种.利用这6对引物的共显性标记可以鉴别籼粳亚种间杂交组合.     

抗除草剂杂交籼稻亲本的配合力分析

本试验以6份新育成的抗除草剂籼型恢复系为父本,5份生产上广泛应用的不育系为母本,采用不完全双列杂交设计配制了30份杂交组合,对其苗期除草剂抗性和主要农艺性状配合力进行了分析。除草剂抗性鉴定表明,亲本恢复系及三系杂交组合抗性接近完全,两系杂交组合抗性达90%以上。配合力分析表明,不育系除单株有效穗数外其他农艺性状的一般配合力均达到极显著差异;恢复系间一般配合力在所有性状中均达到显著或极显著差异;杂交组合间特殊配合力方差仅在单株产量、结实率、播始历期和千粒重4个性状中达到显著或极显著差异。不育系中,金科1A在单株产量、结实率等7个性状上的一般配合力均为最高,但其特殊配合力方差最小;广占63-4S在千粒重性状上具有最高的一般配合力、最大的特殊配合力方差,在播始历期上具有最高的一般配合力负效应;C815S在株高上的一般配合力负效应最大,同时特殊配合力方差较高。恢复系中,华抗恢101在单株有效穗数上具有最高的一般配合力和特殊配合力方差;华抗恢104在穗长上具有最高的一般配合力,在播始历期上具有最高的一般配合力负效应;华抗恢105在单株产量、结实率等性状上具有最高的一般配合力,在株高上具有最高的一般配合力负效应;华抗恢106在千粒重性状上具有最高的一般配合力和特殊配合力效应方差。利用抗除草剂恢复系配制杂交组合,不仅可以改良其除草剂抗性,也可以通过广泛测配,选择一般配合力强、特殊配合力方差大的亲本配组育成强优势组合。     

分子标记辅助选择改良水稻不育系臻达A及其杂交种的稻瘟病抗性

水稻抗稻瘟病基因Pi25是一个遗传传递能力强的广谱抗性基因。本研究以携带抗稻瘟病基因Pi25的BL27为抗源供体,与优质、配合力强、感稻瘟病的水稻保持系臻达B为受体亲本进行杂交、回交创制水稻抗病保持系新种质,再与臻达A测交和回交进行不育系转育,结合分子标记辅助选择和农艺性状筛选,获得3个抗性基因纯合、农艺性状和开花习性均与臻达A相似的改良不育系株系。利用福建省近年来致病性代表的22个稻瘟病菌株对3个改良不育系及其15个杂交种进行抗性鉴定,3个改良不育系的抗性频率为95.45%~100%,15个杂交种的抗性频率均达75%以上,而原始对照臻达A及其杂交种的抗性频率仅为54.55%和40.91%~63.64%。自然病圃诱发鉴定表明,3个改良不育系的叶瘟和穗颈瘟均为0级,表现高抗,而对照臻达A的叶瘟为5级,穗颈瘟为7级,表现感病;15个杂交种均表现良好的稻瘟病抗性。进一步分析比较15个杂交种的产量、农艺性状和稻米品质表现,结果表明臻达A-Pi25-3改良不育系的综合性状表现最优,继续回交转育,于2015年育成了稻瘟病抗性强、配合力好、群体整齐和性状稳定的不育系,命名为157A。研究表明,抗稻瘟病基因Pi25不仅在水稻不育系臻达A的遗传背景下的抗性表达完全,且在不同水稻恢复系测交种的背景下同样表现出较高水平的抗性,说明抗性基因Pi25对不育系稻瘟病改良的效果明显。创制的新不育系157A的稻瘟病抗性显著提高,还基本保留了原来不育系高配合力等优良特性,为选育高产、优质、抗病杂交稻新品种提供了不育系新种质。     

杂交水稻苗瘟抗性的配合力和遗传力分析

采用7×7不完全双列杂交设计,对反映杂交水稻苗瘟抗性的5个指标进行了配合力和遗传力分析.结果表明,杂交水稻苗瘟抗性遗传力高,受加性和非加性基因效应共同控制,但以加性效应为主;恢复系的苗瘟抗性一般配合力效应明显相对重要于不育系,不育系苗瘟抗性一般配合力效应对F1代的抗性有显著的影响;14个供试亲本中,多恢1号、成恢149、K42A、K40A具有较好的苗瘟抗性一般配合力效应.因此,在杂交水稻抗苗瘟育种中,对恢复系的抗性GCA选择和对亲本的抗性GCA评鉴至关重要,但不应忽视不育系对组合的抗性贡献和对组合的抗性评鉴;多恢1号、成恢149、K42A和K40A可作为优良抗苗瘟亲本加以利用.     

三基因聚合改良恢复系福恢673的稻瘟病抗性

为了改良水稻优良恢复系福恢673的稻瘟病抗性,以该恢复系为轮回亲本,以携有3个稻瘟病抗性基因(Pi-1、Pi-9和Pi-k~h)的优质恢复系金恢1059为供体亲本,通过回交育种结合分子标记辅助选择,选育出10个导入了这3个抗稻瘟病基因的福恢673近等基因系,其遗传背景恢复率为92.96%–98.59%。抗性鉴定结果表明,这些近等基因系及其与不育系宜香A配制的杂种一代均表现抗稻瘟病,抗性明显强于对照福恢673和宜优673,且半数以上杂种一代基本保留了原组合的主要优点。用近等基因系Line 9配组的杂交稻新组合两优7283和金泰优683在区试中均表现出产量高、稻瘟病抗性强、生育期适中等特点,表明该近等基因系具较好的应用前景。     

六倍体小黑麦T型细胞质雄性不育体系杂种优势与配合力的研究

用具提莫菲维小麦细胞质的六倍体小黑麦的3个不育系和3个恢复系作为亲本,进行3×3不完全双列杂交,对所组配的F1代8个农艺性状的杂种优势分析结果表明,除千粒重外,其余性状出现正向超亲优势的组合较少,多数呈低亲或中亲遗传,且各组合间的差异比较显著。配合力分析表明,一般配合力与特殊配合力的方差均达到了显著水平,F1各性状均受基因加性效应和非加性效应共同作用;从总体上看,不育系A1、A2及恢复系R1、R2的一般配合力良好,其配制的组合优势较强,具一定的利用价值。对一般配合力与亲本表型值进行了相关分析,二者无显著的相关关系。     

Molecular marker heterozygosity and hybrid performance in indica and japonica rice

An essential assumption underlying markerbased prediction of hybrid performance is a strong linear correlation between molecular marker heterozygosity and hybrid performance or heterosis. This study was intended to investigate the extent of the correlations between molecular marker heterozygosity and hybrid performance in crosses involving two sets of rice materials, 9 indica and 11 japonica varieties. These materials represent a broad spectrum of the cultivated rice gene pool including landraces, primitive cultivars, historically important cultivars, modern elite cultivars and parents of superior hybrids. Varieties within each set were intermated in all possible nonreciprocal pairs resulting in 36 crosses in the indica set and 55 in the japonica set. The F₁s and their parents, 111 entries in total, were examined for performance of seven traits in a replicated field trial. The parents were surveyed for polymorphisms using 96 RFLP and ten SSR markers selected at regular intervals from a published molecular marker linkage map. Molecular marker genotypes of the F₁ hybrids were deduced from the parental genotypes. The analysis showed that, with very few exceptions, correlations in the indica dataset were higher than in that of their japonica counterparts. Among the seven traits analyzed, plant height showed the highest correlation between heterozygosity and hybrid performance and heteorsis in both indica and japonica datasets. Correlations were low to intermediate between hybrid performance and heterozygosity (both general and specific) in yield and yield component traits in both indica and japonica sets, and also low to intermediate between specific heterozygosity and heterosis in the indica set, whereas very little correlation was detected between heterosis and heterozygosity (either general or specific) in the japonica set. In comparison to the results from our previous studies, we concluded that the relationship between molecular marker heterozygosity and heterosis is variable, depending on the genetic materials used in the study, the diversity of rice germplasms and the complexity of the genetic basis of heterosis.     

Prediction of hybrid grain yield performances in Indica Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) with effect-increasing loci

One hundred and fifty-one rice hybrids produced in two sets of half-dialell crosses and their parents (13 cytoplasmic male sterile lines and 19 restorers) were used to predict the F₁ performances of seven yield traits through the parental genetic distances (GD) based on SSR markers. The positive loci (PL) and effect-increasing loci (IL), which were screened from SSR polymorphic loci by the F₁ traits of 32 parents, together with total loci (TL), were utilized to estimate parental GD and the models were found to predict the traits of hybrids derived from different parents, fixed parents, and different environments, respectively. The results were as follows: (1) 550 polymorphic loci were detected from 174 SSR markers: a dendrogram based on these loci could separate all the sterile and restorer lines used in the present study, which indicated that parental genetic diversity of F₁ was large; (2) the correlations between F₁ traits and parental GDs based on IL ranged from 0.61 to 0.87 with a mean of 0.76, and they were higher than those on TL or on PL; (3) predictions based on IL for F₁ traits (except grain weight per plant) derived from different environments were ideal, but worse for F₁ traits derived from different parents; and (4) IL was more effective than TL and PL in predicting traits of F₁ with fixed parents, and predictions for fixed restorer combinations were more effective than those for fixed sterile line combinations. These results should facilitate molecular prediction for hybrid yield and other traits by means of both elite sterile and restorer lines.     

粳稻糙米钙含量QTL分析

以'十和田'为轮回亲本,'丽粳2号'为供体,培育出糙米钙含量近等基因系下的重组近交系261个BC_5F_6株系,采用BSA法从遍布水稻12条染色体上的600对SSR引物中筛选到1个与糙米钙含量有关联的SSR标记RM5536.进一步据其在水稻染色体上的位置,结合PCR找到了与糙米钙含量有关的3个SSR标记(RM5794、RM5362和RM12178).用MAPMAKER/EXP3.0软件做出了这4个标记的连锁群,最后采用混合线性模型找到了糙米钙含量QTL位点.QTL分析结果显示:该位点位于1号染色体引物RM12178和RM5362之间,贡献率为9.62%,为新发现的糙米钙含量QTL位点,暂命名为qBRCA-1.并发现与糙米锶含量有关的QTL位点,其位于标记RM5362和RM5794之间,贡献率为3.93%.同时本试验首次从分子水平上验证了偏相关比简单相关更准确解释元素间的相关性.     

普通野生稻中增产相关QTL的发掘

普通野生稻(Oryza Rufipogon)是重要的遗传资源,发掘其优良等位基因将对水稻遗传改良产生重要影响。文章从以珍汕97为轮回亲本,普通野生稻为供体的BC2F1群体中选择一个与珍汕97表型明显不同的单株BC2F1-15,经过连续自交获得回交重组自交系BC2F5群体。均匀分布于12条染色体的126个多态性SSR(Simplesequence repeats)标记基因型分析,发现BC2F1-15单株在30%的标记位点为杂合基因型;利用该群体共检测到4个抽穗期、3个株高、4个每穗颖花数、2个千粒重和1个单株产量QTL。在第7染色体RM481-RM2区间,检测到抽穗期、每穗颖花数和产量QTL,野生稻等位基因表现增效作用;其他3个每穗颖花数QTL位点,野生稻等位基因也均具有增效作用。结果表明野生稻携带有增产相关的等位基因,这些有利等位基因无疑是水稻遗传改良可资利用的新资源。     

SSR heterogenic patterns of parents for marking and predicting heterosis in rice breeding

The most important concerns of hybrid rice breeders are selection of donors to improve parental lines and prediction of hybrid performance. In this study, SSR molecular marker technology and a half-diallel method were used to address these related hybrid production issues. The results show that genetic diversity among the parental lines is certainly related to heterosis. The heterozygosity of each parental pair is significantly associated with the general combining ability, not with the specific combining ability. However, neither genetic diversity nor heterozygosity is a good indicator for predicting heterosis. From these results, it is suggested that donors for improving parents of hybrids be selected from the improved inbred lines by conventional breeding programs. In this investigation, we also discovered that four favorable alleles and six favorable heterogenic patterns on the parental lines significantly contribute to the heterosis of their hybrids in grain yield, whereas six unfavorable alleles and six unfavorable heterogenic patterns significantly reduce heterosis. These noticeable findings could be, in practice, useful for hybrid rice breeding programs with SSR marker-assisted selection. It is suggested that the optimal combinations with the superior grain yield could be bred out by assembling those favorable alleles into their parental lines and by removing the unfavorable alleles from the parental lines. This study also indicates that there is still a great heterosis potential to be exploited in indica/indica hybrids by the same strategy. In indica/japonica hybrid breeding programs, it may also be important to remove unfavorable alleles rather than broaden genetic diversity or heterozygosity of the parents.     

马铃薯杂种F1的SSR鉴定

为选育抗黑痣病、高产优质的马铃薯新品种,选用引进品种‘大西洋’分别与‘陇薯6号’、‘陇薯7号’杂交,获得了杂种F1代,利用SSR标记技术对‘大西洋’与‘陇薯6号’的42个杂种F1、‘大西洋’与‘陇薯7号’的9个杂种F1单株进行了鉴定。从59对SSR引物中筛选出2对在亲本间存在差异、扩增稳定、条带清晰的引物S184和STM1049,用于‘大西洋’ב陇薯6号’杂种F1、‘大西洋’ב陇薯7号’杂种F1及其亲本的基因组DNA扩增。SSR带型分析显示,杂种F1的SSR带型呈双亲互补型、缺失型、父本型和母本型4类,依据带型特征鉴定出供试的51个马铃薯杂种F1单株均为真杂种,表明SSR分子标记技术用于马铃薯杂种真实性鉴定是可行的。该研究可为进一步开展马铃薯杂交后代目标性状优异株系选育提供依据。     

QTL mapping and introgression of yield-related traits from <Emphasis Type="Italic">Oryza glumaepatula</Emphasis> to cultivated rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>) using microsatellite markers

Rice ( Oryza sativa) cultivar development currently faces the task of overcoming yield plateaus, which is difficult due to the narrow genetic base of breeding programs. Oryza glumaepatula is a diploid wild relative of cultivated rice, native to Central and South America, and is therefore a potential source of alleles of agronomic importance to rice breeding programs. We studied 11 agronomic traits in BC(2)F(2) families of the interspecific cross Oryza sativa x O. glumaepatula. Transgressive lines which are almost isogenic to the elite recurrent O. sativa parent were identified for most of these traits. Quantitative trait locus (QTL) analysis was performed by single-point and interval mapping using a molecular map based on 157 microsatellite and STS markers. Marker regions accounting for 14.5 to 72.9% of a phenotypic variation trait were identified in 9 of the 12 rice chromosomes. Positive QTL effects from O. glumaepatula were observed in chromosomal regions associated with tillering and panicle-number traits.     

中国17个优良玉米自交系的分子标记杂合性及其与杂交种性状的关系研究

在玉米单交种育种中 ,鉴定高产杂交种和具有优良特性的自交系是一个重要的问题。研究以 1 7个优良玉米自交系为亲本 ,按照双列杂交配组合 ,利用 RAPD技术分析了 1 7个自交系的多态性以及 RAPD标记与 9个重要农艺性状 (包括产量 )的关系。基于 RAPD标记计算的相似系数聚类将 1 7个自交系分为 5个类群 ,经分析与系谱亲缘关系基本一致。杂交种性状及其特殊配合力与亲本间的遗传距离是高度相关的 ,与聚类前比较 ,聚类后平均遗传距离与平均产量、平均特殊配合力的相关系数显著提高 ,类间平均产量高于类内平均产量。RAPD技术可揭示优良玉米自交系的系谱亲缘关系 ,将自交系划分成不同的类群 ,从而为选择类间自交系杂交 ,进行亲本选配和分子标记辅助育种提供一种方法。     

Genome‐wide association analyses reveal the genetic basis of combining ability in rice

Combining ability is a measure for selecting elite parents and predicting hybrid performance in plant breeding. However, the genetic basis of combining ability remains unclear and a global view of combining ability from diverse mating designs is lacking. We developed a North Carolina II (NCII) population of 96 Oryza sativa and four male sterile lines to identify parents of greatest value for hybrid rice production. Statistical analyses indicated that general combining ability (GCA) and specific combining ability (SCA) contributed variously to different agronomic traits. In a genome‐wide association study (GWAS) of agronomic traits, GCA and SCA, we identified 34 significant associations (P < 2.39 × 10^?7). The superior alleles of GCA loci (Ghd8, GS3 and qSSR4) accumulated in parental lines with high GCA and explained 30.03% of GCA variance in grain yield, indicating that molecular breeding of high GCA parental lines is feasible. The distinct distributions of these QTLs contributed to the differentiation of parental GCA in subpopulations. GWAS of SCA identified 12 more loci that showed dominance on corresponding agronomic traits. We conclude that the accumulation of superior GCA and SCA alleles is an important contributor to heterosis and QTLs that greatly contributed to combining ability in our study would accelerate the identification of elite inbred lines and breeding of super hybrids.