杂交粳稻亲本产量性状优异配合力的标记基因型筛选

提高杂交粳稻竞争优势的关键是改良其恢复系产量性状的配合力。为使之更富成效,选用115个SSR引物扩增6个粳稻BT型不育系和12个恢复系的标记基因型,并按NCII遗传设计配制72个F1组合,分析18个亲本的单株日产量、单株有效穗数、每穗总粒数、每穗实粒数、千粒重5个性状的配合力,结合亲本SSR分子标记数据和性状配合力数据筛选了5个性状优异配合力的标记基因型。结果发现20个SSR标记基因型与亲本产量及其构成性状配合力显著相关。其中8个与亲本单个性状配合力相关;6个同时与亲本2个性状配合力相关;4个同时与亲本3个性状配合力相关;2个同时与亲本4个性状配合力相关。同时与多个性状配合力相关的标记基因型,对各性状的作用方向有正有负。RM152-165/170是单株日产量和单株有效穗数优异配合力效应最大的标记基因型,可使F1的相应性状值增加20.6%和12.7%。优异配合力的标记基因型可直接用于粳稻恢复系配合力的分子标记辅助改良。     

不同供体及不同回交次数对玉米自交系R08的改良效应

以R08为轮回亲本,18个优良自交系为供体亲本,不同回交和自交次数,选育出遗传背景与R08相近、但相互之间又存在一定差异的BC₁F₃和BC₂F₂各18个R08改良系。通过抗病性鉴定、配合力及SSR分子标记分析,探讨不同供体及不同回交次数对R08的改良效果。结果表明,36个改良系中,29个抗或高抗大斑病,大部分改良系的多数产量性状一般配合力(GCA)与R08相比并无下降或有所提高;相同供体不同回交次数选系的比较显示,对大斑病抗性的改良,回交1次自交2次(BC₁F₃)优于回交2次自交1次(BC₂F₂),且改良后代选系多数产量性状GCA大体相当;相同回交次数不同供体选系的比较表明,供体对回交后代的影响较大,供体不同回交后代选系大斑病抗性及多数产量性状GCA存在较大的差异;SSR分子标记研究结果在一定程度上揭示相同供体不同回交次数所创造的遗传变异无明显差异,相同回交次数不同供体选系在分子水平上存在较大差异;供体昌7-2和川321对改良R08的大斑病抗性和产量性状GCA作用较大,属优良供体亲本;w4-1和w10-1属回交改良优良选系。因此,利用回交法改良玉米自交系,在选准供体亲本的基础上,回交1次后,在自交过程中加强目标性状的鉴定选择及配合力测定,可提高回交改良的育种效率。     

利用极端材料定位水稻粒形性状数量基因位点

利用极端大粒材料GSL156(千粒重71.9 g)与特小粒材料川七(千粒重12.1 g,轮回亲本)杂交、回交获得的BC₂F₂ 216个个体为作图群体,在北京进行稻谷粒长、粒宽、粒厚、长宽比、千粒重等粒形性状的鉴定。采用单标记分析和复合区间作图法,利用SSR标记对粒形性状进行数量性状基因座检测。结果表明,上述粒形性状在BC₂F₂群体均呈正态连续分布,表现为由多基因控制的数量性状;共检测到与粒形性状相关的QTL 28个,分布于第1、2、3、4、5、6和12染色体上。其中qGL3-2、qGL3-3、qGT12-1、qGT2-1、qGT5-1、qGW1-1、qGW12-1、qGW2-1、qGW5-1、qRLW3-1、qTGW12-1、qTGW2-1、qTGW3-3和qTGW5-1对表型变异的贡献率分别为13.70%、52.51%、21.13%、18.79%、20.92%、14.59%、18.33%、30.03%、20.05%、24.53%、13.47%、11.43%、21.30%和15.68%,为主效QTL。其中,第3染色体上检测出来的QTL最多。在所有检测到的28个QTL中,6个QTL的增效等位基因来源于小粒亲本川七,而其余QTL的增效等位基因均来源于大粒亲本GSL156,基因作用方式主要表现为加性或部分显性。第3染色体RM7580~RM8208区间是分别与粒宽、长宽比和千粒重相关的3个主效QTL的共同标记区间,第2染色体的RM7636~RM5812区间、第5染色体的RM3351~RM26区间和第12号染色体的RM1103~RM17区间是分别与粒宽、粒厚和千粒重相关的3个主效QTL的共同标记区间,这些区间对粒形贡献率较大,为进一步精细定位或克隆这些新的粒重或粒形QTL奠定了基础。同时大粒亲本对稻谷粒长、粒宽、粒厚和千粒重等性状的增效作用显著。     

不同类型杂交早稻品质性状遗传分析

目前中国早稻食用品质较差,为今后选育优质杂交早稻组合提供理论依据,选用生产上常用的8个杂交稻不育系和12个杂交早稻恢复系（品种）,采用不完全双列杂交配置了96个不同杂交早稻组合,对各杂交早稻组合及其亲本的12个米质性状进行了测定和遗传分析。结果表明,96个不同杂交早稻组合的各米质性状存在极其明显的组合间遗传差异;杂交早稻组合各米质性状除糙米率、精米率、胶稠度和蛋白质质含量外,其余米质性状的一般配合力方差在总的基因型方差中所占比重均大于50%;除糙米率和精米率外,其余米质性状受父本的影响大于母本;杂交早稻各米质性状的表型相关系数、遗传相关系数和相关遗传率三者之间均呈极显著水平的俩俩正相关;杂交早稻米质性状间的选择相对效率较高的有米粒长对长/宽,垩白面积对垩白度,垩白面积对垩白度,垩白粒率对垩白度,糙米率对精米率,其它米质性状之间的间接选择相对效率均较低。     

江淮稻区杂交粳稻骨干亲本产量性状配合力的SSR标记位点鉴定

鉴定杂交粳稻亲本产量性状配合力的标记位点有助于利用分子标记辅助选择技术改良亲本配合力、提高杂交粳稻竞争优势水平。利用9个粳稻BT型不育系和10个恢复系, 按照北卡罗林那设计II (North Carolina Design II)配制90个F₁组合,在南京和盱眙两个环境下种植,测定了各亲本产量性状的配合力和SSR分子标记基因型;结合二者数据鉴定了6个产量性状配合力的标记位点。结果表明,在两个环境下综合评价配合力较优的不育系是BT-18A和武羌A,恢复系是C418。与亲本单株有效穗数、每穗总粒数、每穗实粒数、结实率、千粒重和单株日产量性状配合力显著相关的SSR标记位点,南京环境下分别检测到8、13、11、6、6和2个;盱眙环境下分别检测到12、21、8、15、10和7个;2个环境下都检测到的分别有4、11、5、3、5和1个。标记位点杂合基因型显示正向优势的,南京环境下占74% (34/46);盱眙环境下占53% (39/73)。2个环境下都检测到的标记位点中,有3个各自与3个产量性状配合力共相关;另有3个各自与2个产量性状配合力共相关;其余的只与单个产量性状配合力显著相关。数据库检索发现两环境下都检测到的标记位点中,有10个其附近存在控制相应性状的基因/QTL。讨论了利用鉴定出的标记位点改良粳稻恢复系产量性状配合力的策略。     

影响水稻穗部性状及籽粒碾磨品质的QTL及其环境互作分析

利用优质恢复系测258为轮回亲本与粳型糯稻新品系IR75862杂交创制的BC₁F₇回交导入系群体,在广西南宁和海南三亚定位了产量相关性状(二次枝梗数、穗总粒数、穗实粒数、粒重和穗重)、粒型(粒长、宽、厚)和碾磨品质(糙米率、精米率和整精米率)的主效QTL并剖析其环境互作效应。双亲在穗实粒数、千粒重、粒长和粒宽及整精米率等性状上存在显著差异。各产量相关性状间呈极显著正相关,而与千粒重和粒长呈极显著负相关。多数产量及粒型相关性状与3种碾磨品质相关不显著。在南宁和三亚环境下检测到影响产量相关性状、粒型及碾磨品质的主效QTL共计57个,包括二次枝梗数的6个,穗实粒数4个,穗总粒数、粒重和穗重各5个,粒长9个,粒宽7个,粒厚1个,糙米率4个,精米率5个和整精米率6个,分布在除第11染色体外的所有染色体上。多数影响枝梗数、穗粒数和粒重的QTL成簇分布,而且与影响BR、MR和HR的QTL分布在不同染色体区域。在第2、第3、第4、第5和第6染色体上鉴定出影响穗粒数、粒重、粒型及碾磨品质的重要QTL,这些QTL在以往不同遗传背景和环境下被多次检测到。在第8染色体RM152~RM310区间鉴定到1个影响粒长和粒宽的新的QTL,能同步增加粒宽和粒长。鉴定出的这些稳定表达的QTL具有标记辅助选择育种的应用价值。整精米率是受环境影响最大的性状,其QTL的环境互作效应明显。对QTL的环境互作效应特点及其在品种标记辅助改良中的作用进行了深入探讨。     

分子标记辅助选择改良武运粳8号的条纹叶枯病抗性

本研究旨在改良武运粳8号的条纹叶枯病抗性。2004年,在扬州对江苏省1981—2002年间审定的25个迟熟中粳品种进行产量鉴定,从中筛选出直立穗高产品种武运粳8号作为条纹叶枯病抗性改良的受体亲本。利用抗条纹叶枯病品种葵风为供体亲本,通过杂交和回交,同时利用4个与条纹叶枯病抗性基因紧密连锁的分子标记STS11-31、STS11-71、STS11-19和STS11-43进行辅助选择,至2008年正季,共计获得 70个BC₃F₅以及115个BC₄F₄抗条纹叶枯病的稳定株系。经回交后代农艺性状、产量性状、品质性状和抗性的系统鉴定,从中筛选出10个BC₄F₅株系和2个BC₃F₆株系,这些株系综合性状与武运粳8号已十分相近,保持了武运粳8号的丰产性和优质,明显提高了条纹叶枯病的抗性。     

水稻显性早熟基因Ehd的SSR标记定位

以籼稻品种广陆矮4和粳稻品种台中65为亲本构建高世代回交分离群体,选用分布于水稻全基因组的145个SSR标记对亲本及抽穗期早熟基因进行分析.结果表明,114个标记在亲本间具有多态性,多态率78.6%;在BC3F1群体中,检测到10个标记的基因型来源于供体亲本广陆矮4号;在BC3F2定位群体中,早熟植株数与晚熟植株数的分离比例为3:1,早熟植株平均比晚熟植株提早抽穗21 d;通过SSR标记与抽穗期共分离分析将显性早熟基因Ehd界定在分子标记RM271和RM258之间;Ehd与标记RM184和RM271紧密连锁,遗传距离分别为2.6 cM和2.1 cM,此结果为该基因分子标记辅助选择奠定了基础.     

籼型三系杂稻品质性状的配合力及遗传力分析

以3个不育系川香29A(A1)、珍汕97A(A2)、Ⅱ-32A(A3)和8个新恢复系为亲本,按不完全双列杂交模式分析11个品质性状的配合力及遗传力。结果表明:(1)大多数性状的一般配合力(gca)和特殊配合力(sca)达显著或极显著水平,即受基因加性效应和非加性效应的共同控制,且以加性效应占主导地位(2)精米率、垩白度、直链淀粉含量3个性状,恢复系对gca方差的贡献比不育系的大,而不育系在粒长、粒宽、长宽比、糙米率、整精米率、垩白率、胶稠度等性状上对gca方差的贡献比恢复系的大。糊化温度这两性状,恢复系和不育系对gca方差的贡献相近。(3)广义遗传力(h2B)降序排序为:粒长、长宽比、垩白率、粒宽、糊化温度、胶稠度、整精米率、糙米率、直链淀粉含量、精米率、垩白度,变幅在93.36%～38.13%之间;狭义遗传力(h2N)降序排序为:粒长、长宽比、垩白率、糙米率、糊化温度、整精米率、垩白度、胶稠度、精米率、直链淀粉含量,变幅在82.3%～17.32%之间。大部分性状的(h2N)与(h2B)的趋势是一致的。(4)gca效应值在同一性状不同亲本间和同一亲本不同性状间均存在显著的差异,亲本中A1、R8、R7较为理想。     

冬小麦种质“矮孟牛”姊妹系遗传差异

采用田间试验鉴定和基因组分子标记分析相结合的方法,对冬小麦种质“矮孟牛” 7个类型的性状和基因组遗传差异比较分析。结果表明,7个类型在调查的株高、穗长、穗粒数、粒长、粒宽、单株穗数等16个性状方面存在差异,其中矮孟牛V型的主要产量构成因素等性状比较协调,总体优于其他6个类型。在检测的2 210对SSR、EST-SSR和STS标记中,有656对标记可在矮孟牛三亲本中显示多态性,将其用于矮孟牛7个类型全基因组遗传差异分析,并利用GGT2.0绘制7个类型的遗传差异图谱。在矮孟牛V型的1A、1B、2D、3A、4D、7A染色体上检测到8个特异位点,利用矮丰3号/牛朱特和孟县201/牛朱特构建的2个F₂分离群体,经IciMappingV3.0单标记QTL作图分析,发现矮孟牛V型部分特异位点附近存在与产量构成因素等重要性状相关的QTL。矮孟牛V型的基因组特异位点可能是它作为骨干亲本区别于其他姊妹系的重要基因组特征。     

Identification of genome-wide SNPs associated with combining ability for grain quality traits in parents of hybrid japonica rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Improving the combining ability for grain quality traits of the parents is the key factor to enhance averaged bulk grain quality of hybrid japonica rice. Eight quality traits including brown rice rate, milled rice rate (MRR), head rice rate (HRR), chalkiness degree (CD), percentage of chalky grain (PCG), alkali spreading value (ASV), gel consistency (GC) and amylose content (AC) of the bulked sample of rough rice harvested from the 81 F₁ hybrid plants were investigated in 2014 and 2015. By combining the phenotypic data of general combining ability (GCA) for the quality traits with genotypic data of single nucleotide polymorphism (SNP) obtained by genotyping by sequencing method, CAScreen1.0 program compiled by MATLAB language was conducted to identify the elite SNP genotype associated with combining ability of quality traits in parents. Totally 35 elite SNP genotypes involving 22 genes (genotypes) were detected associated with GCA of seven quality traits (P?<?0.05) in both 2014 and 2015. Seven and four SNPs were detected associated with combining ability for MRR and HRR, respectively. For PCG and CD, six and ten SNPs were detected associated with combining ability of parents, respectively. Six SNPs involving two genes were detected for combining ability of GC. Only two SNPs were detected which associated with combining ability for ASV. For combining ability of AC, six elite SNPs genotype were detected. Among them, elite SNP genotype of LOC_Os08g25220 (T/C) located on chromosome 8 could significantly reduce AC content in mixed rice samples of hybrid japonica rice.     

粳稻米碱消值的数量性状基因座检测

利用碱消值差异显著的大粒粳稻DL115与小粒粳稻XL005杂交获得的200个单株F2群体为作图群体,采用复合区间作图方法,利用SSR标记进行了粳稻碱消值数量性状基因座的检测。结果表明,在F2群体中碱消值呈正态连续分布,表现为由多基因控制的数量性状。共检测到与碱消值相关的QTL3个,qADV3、qADV5和qADV11,分别位于第3、第5和第11染色体的RM14870～RM1284、RM3838～RM3351和RM1812～RM332区间,对表型变异的解释率分别为6.5%、10.3%和8.1%。qADV5的增效等位基因来自碱消值较小的亲本XL005,qADV3和qADV11的增效等位基因来自碱消值较大的亲本DL115;基因作用方式表现为显性或超显性。     

Bulked segregant analysis to detect main effect QTL associated with grain quality parameters in Basmati 370/ASD 16 cross in rice Oryza sativa L) using SSR markers

In the present study a population consisting of 247 F₂ individuals from the cross between Basmati 370, a superior quality basmati variety and ASD16, a non-basmati high-yielding variety was analyzed for their segregation pattern of grain length (GL), grain breadth (GB), cooked grain length (CGL), cooked grain breadth (CGB), and gelatinization temperature (GT). Except GT, all other traits showed normal distribution indicating the polygenic control over the traits. The correlation analysis between traits indicated that GT had positive significant association with GL (0.125), and CGL (0.243). To identify main effect QTL (MQTL) for the above grain quality traits, both the parents were surveyed with 86 primer pairs of simple sequence repeats (SSR). The parental survey revealed 63.95% polymorphism between parents. In order to detect the MQTL associated with grain quality traits, a strategy of combining the DNA pooling from selected segregants and genotyping was adopted. The number of individuals forming the bulk influenced the identification of putative marker(s) for each of the traits. The association of putative markers identified based on DNA pooling from selected segregants was established by Single Marker Analysis (SMA). The results of SMA revealed that SSR markers, RM225 on chromosome #6 and RM247 on chromosome #12 showed significant association with GB and CGB respectively. It is established that molecular marker analysis involving DNA pooling of phenotypic extremes and selective genotyping helps to detect MQTL for complex traits involving early segregating generations. The molecular marker analysis involving the DNA pooling of phenotypic extremes could be a useful strategy to detect the genetic loci with major effects of other complex grain quality traits in rice.     

Quantitative trait loci for grain-quality traits across a rice F2 population and backcross inbred lines

Improving grain-quality is an important goal in rice breeding programs. One vital step is to find major quantitative trait loci (QTLs) for quality related traits and then investigate the relationships among them. We crossed ‘N22’, an indica variety with good appearance but low grain weight, to a japonica variety, ‘Nanjing35’, with superior grain yield but poor appearance. This enabled us to construct an F₂ population and a set of backcross inbred lines (BILs) for QTL-mapping for the traits related grain appearance. In all, 37 QTLs were identified for grain length (GL), grain width (GW), grain thickness (GT), thousand-grain weight (TGW), and the percentage of grains with chalkiness (PGWC). Of these, 17 QTLs detected from 184 plants in the F₂ population explained 4.97–27.26 % of the phenotypic variance, another 20 QTLs were identified using BILs from 2009 to 2010. Quantitative trait loci for major effects were detected in different populations and across years. A new QTL hot spot (marker interval RM504–RM520) was found on Chromosome 3, which harbored QTLs for GL, GW, GT, and TGW. Among our five examined traits, grain shape was significantly correlated with TGW and PGWC. The PGWC values of two heavier grains BILs, L93, and L145 are much lower than Nanjiing35, the analysis of genotype showed that this greater weight may due to the locus for GL occurring within RM504–RM520 on Chromosome 3. Therefore, those two lines will allow us to develop a long-grain high-yield rice variety with less chalkiness.     

利用RIL群体对水稻再生力及相关农艺性状的QTL分析

以粳糯稻品种糯89-1与籼型重穗型杂交稻骨干恢复系蜀恢527杂交构建的籼粳交F₇代RIL群体的169个家系为作图群体,构建了一张含105个微卫星(SSR)标记的分子连锁图谱。定位了水稻正季7个农艺性状的QTL 15个,分布在第1、第2、第3、第5、第6、第7、第10染色体上,LOD值介于2.10~7.51,贡献率3.77%~25.37%,其中贡献率10.0%以上的QTL 7个,单个性状的QTL 1~4个;定位了水稻再生季7个农艺性状的QTL 19个,分布在第1、第2、第3、第4、第5、第6、第7、第10染色体上,LOD值介于2.17~18.34,贡献率3.23%~37.66%,其中贡献率10.0%以上的QTL 7个,单个性状的QTL1~5个;定位了影响水稻再生力(最终再生率)的QTL 2个(qRa4,qRa5),分别在第4和第5染色体上,贡献率分别为8.17%和7.09%,加性效应分别为0.32和-0.39,贡献率和加性效应均较小,属微效基因。共检测到两季农艺性状QTL 36个,同一性状被重复检测的QTL 8个。水稻再生力与正季稻有效穗呈极显著负相关;水稻再生力与再生稻有效穗呈极显著正相关,与每穗总粒数和着粒密度呈显著负相关。QTL定位结果揭示了有效穗是影响再生力的主要因素。     

Mining of favorable marker alleles for flag leaf inclination in some rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) accessions by association mapping

Flag leaf angle (FLA) in rice (Oryza sativa L.) is one of the important traits affecting F₁ seed production by mechanization. To elucidate the genetic mechanism of FLA and mine favorable marker alleles for F₁ seed production in rice, we performed a genome-wide association study using phenotypic data over 2 years and genotypic data of 262 pairs of simple sequence repeat (SSR) markers collected from 441 rice accessions. We detected seven SSR marker loci associated with FLA and four loci were novel. The four newly found loci were RM6266 on chromosome 3, RM348 on chromosome 4, RM258 on chromosome 10 and RM7303 on chromosome 11. We found a total of 27 favorable alleles, of which four, i.e., RM348-130 bp, RM7303-90 bp, RM258-180 bp, and RM4835-230 bp, had phenotypic effects larger than 10°. Nine combinations, which increased FLA by 45.7°–94.7° through pyramiding the favorable alleles contained in seven typical accessions, were predicted.     

一个新的水稻花粉半不育性位点的定位分析

利用一套以籼稻珍汕97B为背景的粳稻日本晴染色体片段代换系,鉴定发现1个半不育的代换系。全基因组基因型分析表明,该代换系仅含3个粳稻导入片段,而其他遗传背景与珍汕97B相同。在湖北武汉和海南分别种植其衍生的F₂和F₃分离群体,采用单标记分析和区间作图法分析花粉育性和小穗育性的数量性状位点(QTL),结果表明,该代换系的半不育性是第2染色体上的粳稻导入片段引起的,该片段RM262~RM475区间存在1个新的影响花粉育性的QTL,其贡献率为13.9%。研究结果将为进一步精细定位水稻育性QTL以及鉴定相关功能基因提供重要的试验基础。     

Validation of molecular markers linked to fertility restorer gene(s) for WA-CMS lines of rice

The present study was carried out with the objective to validate the molecular markers, which have been previously reported to be linked to fertility restorer (Rf) gene(s) for WA-CMS lines of rice. Two mapping populations involving fertility restorer lines for WA-cytoplasm, viz., (i) an F₂ population derived from the cross IR58025A/KMR3R consisting of 347 plants and (ii) a BC₁F₁ population derived from the cross IR62829A/IR10198R//IR62829A consisting of 130 plants were analyzed. Nine SSR and three CAPS markers reported to be linked to Rf genes along with two previously unreported SSR markers were analyzed in the mapping populations. In both the populations studied, the trait of fertility restoration was observed to be under digenic control. Eight SSR markers (RM6100, RM228, RM171, RM216, RM474, RM311, MRG4456 and pRf1&2) showed polymorphism between the parents of the F₂ population, while the SSR markers RM6100 and RM474 showed polymorphism between the parents of both the F₂ and BC₁F₁ populations. Only one CAPS marker, RG146FL/RL was polymorphic between the parents of the BC₁F₁ population. RM6100 was observed to be closely segregating with fertility restoration in both the mapping populations and was located at a distance of ~1.2 cM. The largest phenotypic variation was accounted for the region located between RM311 and RM6100. Using the marker-trait segregation data derived from analysis of both the mapping populations, a local linkage map of the genomic region around Rf-4, a major fertility restoration locus on Chromosome 10 was constructed, and RM6100 was observed to be very close to the gene at a distance of 1.2 cM. The accuracy of the marker RM6100 in predicting fertility restoration was validated in 21 restorers and 18 maintainers. RM6100 amplified the Rf-4 linked allele in a majority of the restorers with a selection accuracy of 94.87%. Through the present study, we have established the usefulness of the marker RM6100 in marker-assisted selection for fertility restoration in segregating populations and identification of restorers while screening rice germplasm for their fertility restoration ability.