甜菜根产量和含糖率性状的QTL定位

为了进行目的基因克隆等进一步的研究,选育高产、高糖、抗病的新品种,由‘JV34-2’和‘2B023’杂交获得F2代群体200株甜菜为材料,利用123个SRAP标记和18个SSR标记,对甜菜的根产量性状和含糖率性状进行QTL定位分析。利用完备区间作图软件QTL icimapping3.1,共检测出根产量和含糖性状的17个QTLs,定位于已构建的遗传图谱的6个连锁群中。根产量性状定位了7个QTLs,LOD值为2.5322~4.0098,可解释变异为4.5704%~12.3782%。含糖率性状定位了10个QTLs,LOD值为2.5385~10.8314,可解释变异为2.3482%~19.3828%。本试验是国内甜菜重要经济性状定位研究中获得QTL定位位点最多的。     

水稻粒形性状的上位性和QE互作效应分析

本研究利用基于明恢86×佳辐占水稻重组自交系(recombinant inbred line,RIL)构建的SSR遗传图谱,总标记数为131.联合两季的稻米粒长(GL)、粒宽(GW)、长宽比(L/W)表型数据,应用混合线性模型方法进行QTL定位,并作加性效应、上位效应以及加性QTL、上位性QTL与环境(QTL-by-environment,QE)的互作效应分析.检测到粒长、粒宽和长宽比的加性效应QTLs分别为6个、4个和4个,贡献率分别为23.67%、21.41%和25.78%;检测到8对粒长的上位性QTLs,5对粒宽的上位性QTLs,2对长宽比的上位性QTLs,贡献率分别为16.75%、22.36%和7.55%;环境互作检测中,发现共有9个加性QTLs和7对上位性QTLs与环境发生了互作.结果表明,上位效应在粒形性状的遗传与加性效应一样起了重要作用,环境互作效应对粒形性状有一定的影响.     

利用籼粳交“热粳35/协B”F_2群体对水稻再生力的QTL分析

为了揭示水稻再生力和再生后期耐寒的遗传基础,本研究以"热粳35/协B"226个F2单株为材料,构建了1张含156个SSR标记的分子图谱。分别在水稻成熟、再生和再生后期调查单株穗数、再生穗数和再生后期穗数,利用Excel 2003和MAPMAKER 3.0软件进行性状相关分析和QTL检测。结果表明,3个性状在F2群体呈现连续正态分布,表现为数量性状遗传特征。再生穗数分别与单株穗数和再生后期耐寒穗数呈极显著正相关(0.37和0.36)。3个性状共检测到10个QTLs,分布在第1、2、6、7、8、11和12号染色体上。其中,数6个单株穗QTLs,LOD值介于2.61~79,贡献率介于0.67%~22.72%。2个再生穗数QTLs,LOD值分别为3.08和3.90,贡献率分别为16.01%和23.35%。2个再生后期穗数QTLs,LOD值分别为2.75和5.12,贡献率分别为12.18%和25.12%。3个性状各检测到1对上位性QTL,相同染色体上相同标记区间没有重复检测到同时控制3个性状QTLs。说明3个性状受独立的遗传因子控制,在分子层面上单株穗数、再生穗数以及再生后期耐寒穗数各性状间没相关性。     

水稻苗期耐冷相关性状QTLs的初步定位

本研究以粳稻品种"藤坂5号"与籼稻品种"江西丝苗"为亲本杂交构建的F2分离群体(137个株系)为作图群体,对F2:3家系的3叶期水稻幼苗冷处理(10℃/8℃,昼/夜)5 d、恢复培养7 d后的耐冷级别、叶枯萎度及苗成活率进行完备区间作图。在分子标记连锁分析过程中共检测到6个控制水稻耐冷性相关性状的QTLs,其中,控制耐冷级别、叶枯萎度及苗成活率的QTLs各有2个,而且每个性状的2个QTLs都分别定位在第8染色体的RM22772-C61344和第11染色体的M100-RM26567区域内,这些QTLs具有较高的耐冷表型贡献率(14.09%~28.60%)。QTL的定位结果采用置换检验(Permutation test)进行了验证,发现控制耐冷级别的2个QTLs的F值都超过了QTL检测的阈值,而叶枯萎度和苗成活率2个性状的QTLs中各有1个QTL(q LWR-8和q SR-11)的F值超过了QTL检测的阈值。研究结果显示在第8和11染色体确实存在2个与水稻耐冷性相关的位点,可为进一步的分析和精细定位打下基础,也为耐冷水稻品种育种和种质创新提供理论依据。     

玉米开花周期的遗传分析

以玉米杂交种农大108(黄C×许178)的F7重组近交系为材料,利用SSR分子标记构建了包括123个标记的连锁图谱,结合重组近交系群体开花周期在南阳、郑州、浚县3点的田间调查结果,利用复合区间作图法对散粉周期和吐丝周期进行QTL定位,共检出12个QTLs。其中,控制吐丝周期的qSC9b在南阳点和浚县点同时检测到,因此共检测到11个不同位点的QTLs,散粉周期检测到5个QTL,吐丝周期检测到6个QTL,单个性状检测到QTL的总效应的遗传贡献率为10.6%～33.1%。在第3染色体上检测到2个控制散粉周期的QTLs和2个控制吐丝周期的QTLs,第9染色体上umc2393～umc1033区段,检测到3个控制吐丝周期的QTLs和1个控制散粉周期的QTLs,表明第3和第9染色体可能是控制玉米开花周期的基因集聚区。     

水稻特异粗茎相关性状QTL的初步定位分析

本研究以新颖的极端粗茎水稻材料R404及细茎品种日本晴为亲本杂交构建的F2分离群体(152个单株)为作图群体,对控制水稻茎秆粗、茎壁厚以及穗颈粗3个茎粗度相关性状的QTL进行定位分析。通过QTL Ici Mapping分子标记作图软件分析,在水稻3、8、11以及12号染色体上分别检测到7个QTLs,其中茎粗和穗颈粗的2个QTL q SDM8.1和qRDM8.1可能为同一基因位点调控,茎粗和茎壁厚的2个QTL qSDM3.1及q SWT3.1也定位在相近的位置,这2个染色体位置可能存在控制茎粗的一因多效的基因。qSWT3.1(15.39%)、qRDM3.1(44.66%)和q SDM8.1(19.16%)在其所控制的相应性状(茎粗,茎壁厚和穗颈部粗)中的贡献率是最大,是主效QTL。除了定位于3号染色体的QTLs外,其他与粗茎性状相关的QTLs均为新发现的QTLs。本研究结果为粗茎QTL的进一步精细定位奠定了基础,也为粗茎QTL应用于水稻抗倒伏品种的培育及种质创新提供重要的基因来源,对保障国家粮食安全具有重要的意义。     

利用重组自交系定位棉花第22染色体短臂的纤维品质性状的QTL

 以TM-1的染色体片段代换系CSB22sh和TM-1杂交,构建了包含104个家系的重组自交系（RILs）群体。利用74对具有多态性位点的引物进行检测,构建了包含61个多态性位点,长度为76.93 cM的遗传图谱,平均标记间距离1.26 cM。利用此遗传图谱结合重组自交系群体4个环境下的5个纤维品质性状进行QTL定位,共定位出12个QTLs,解释性状表型变异的2.45%～21.11%;在1,2,3,4个环境中同时检测到的QTLs分别有9,1,1,1个。而利用4个环境平均值进行联合分析定位出个4个QTLs,纤维长度和纤维整齐度的QTLs均为2个,解释性状表型变异的14.37%～19.97%,并且纤维长度和整齐度的QTL在相同的位置。多环境下检测到的QTL可能对标记辅助选择有实际应用价值。     

杂交棉‘冀1518’纤维品质性状的QTL定位及遗传分析

‘冀1518’是以优质品种‘冀228’为母本,丰产品系‘冀567’为父本配制的适机采杂交棉新品种,为挖掘‘冀1518’的优异纤维品质相关分子标记,本研究利用杂交棉‘冀1518’的亲本构建了F_2、F_(2:3)和F_(2:9)(重组近交系)(recombinant inbred lines, RILs)三个世代的分离群体,并利用SSR分子标记分别以F_2群体和RIL(F_(2:9))群体构建遗传连锁图谱,并对纤维品质性状进行定位。结果表明,F_2作图群体共有15个标记位点连锁,包含4个连锁群,全长覆盖237.10 cM,RIL (F_(2:9))作图群体共有45个标记位点连锁,包含11个连锁群,全长覆盖554.42 cM。利用QTL IciMapping 4.1对F_2、F_(2:3)和RIL (F_(2:9))群体的纤维品质性状进行复合区间作图法分析,在F_2及F_(2:3)分离群体能同时检测到15个与纤维品质相关的QTLs,其中,与马克隆值相关的QTL位点q FM-4-2解释表型变异率最高,为21.10%,显性或超显性效应的QTLs占总数的66.7%,表明显性基因是‘冀1518’纤维品质杂种优势的主要来源。在RIL (F_(2:9))群体定位到6个与纤维品质性状相关的QTLs,解释表型变异率在5.10%～10.26%之间。F_2、F_(2:3)和RIL (F_(2:9))群体均能在HAU2349附近(F_(2:9)作图, 0.31 cM)检测到与断裂比强度和马克隆值相关的QTL位点,在HAU2710附近(F_(2:9)作图, 0.84 cM)检测到与整齐度相关的QTL位点,且上述两标记连锁,连锁区段被定位在A6染色体上。本研究获得在多世代中稳定表达的QTLs,有望用于纤维品质分子标记辅助选择,提高育种效率。     

用(培矮64s/Nipponbare)F2群体对水稻产量构成性状的QTL定位分析

用水稻测序品种培矮64s和Nipponbare为亲本构建的含137个SSRs标记的连锁遗传图谱和(培矮64s/Nipponbare)F2群体的180个单株,对水稻的单株有效穗数、穗粒数、穗实粒数、结实率、穗着粒密度、千粒重等6个产量构成性状进行了QTL定位分析.共检测到6个性状的22个QTLs,分布在第1、2、4、5、6、9、10、11、12等9条染色体的14个区域,表型贡献率5.0%～19.3%;相关性较强的性状之间具有较多共同或紧密连锁的QTLs;集中分布的QTLs之间既有同向连锁,也有反向连锁.对不同水稻群体定位的同源QTL进行了比较,对QTL在染色体上的集中分布,以及用QTL定位结果和生物信息学方法相结合预测基因的功能等进行了探讨.     

利用两个籼稻杂交F_2定位水稻粒型、粒重QTLs

本研究利用两个具有粒型差异的籼稻材料14931和R1961进行杂交、自交获得F2代分离群体。利用在亲本间有多态性的102对SSR标记进行基因型分析,同时对粒长、粒宽、长宽比和粒重4种性状进行了表型鉴定,并采用完备区间作图法(ICIM)对上述性状进行QTL定位。结果表明:上述粒型性状在F2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12个与粒型性状相关的QTLs,分布于第1、第2、第5、第8、第10和第11染色体上。除qgl2-1和qgl2-2之外,其余有10个增效等位基因来自于小粒亲本材料R1946。粒长、粒宽和粒重均分别检测到4个QTLs,但籽粒长宽比未能检测到QTL。其中,qgl1、qgw5-1和qkgw5-1对表型变异的贡献率分别为14.55%、26.28%和15.25%,为主效QTL,并且检测到控制粒长的qgl1可能是新的QTL位点。研究结果可为进一步解析和克隆新的粒型QTLs奠定基础。     

Identification of genomic regions associated with seed dormancy in white-grained wheat

Pre-harvest sprouting (PHS) in developing wheat (Triticum aestivum L.) spikes is stimulated by cool and wet weather and leads to a decline in grain quality. A low level of harvest-time seed dormancy is a major factor for PHS, which generally is a larger problem in white-grained as compared to red-grained wheat. We have in this study analyzed seed dormancy levels at the 92nd Zadok growth stage of spike development in a doubled-haploid (DH) white wheat population and associated variation for the trait with regions on the wheat genome. The phenotypic data was generated by growing the parent lines Argent (non-dormant) and W98616 (dormant) and 151 lines of the DH population in the field during 2002 and 2003, at two locations each year, followed by assessment of harvest-time seed dormancy by germination tests. A genetic map of 2681 cM was constructed for the population upon genotyping 90 DH lines using 361 SSR, 292 AFLP, 252 DArT and 10 EST markers. Single marker analysis of the 90 genotyped lines associated regions on chromosomes 1A, 2B, 3A, 4A, 5B, 6B, and 7A with seed dormancy in at least two out of the four trials. All seven putative quantitative trait loci (QTLs) were contributed by alleles of the dormant parent, W98616. The strongest QTLs positioned on chromosomes 1A, 3A, 4A and 7A were confirmed by interval mapping and markers at these loci have potential use in marker-assisted selection of PHS resistant white-grained wheat.     

Mapping quantitative trait loci controlling pre-harvest sprouting resistance in a red × white seeded spring wheat cross

Hard white wheat (Triticum aestivum L.) is a value-added product because of its processing advantages over red wheat; however, white wheat tends to be more susceptible to pre-harvest sprouting (PHS). To identify quantitative trait loci (QTLs) associated with PHS tolerance, we developed a doubled haploid (DH) mapping population from the cross AC Domain (red seeded) × White-RL4137 (white seeded). A genetic map was constructed using microsatellite markers located on chromosome groups 3, 4, 5 and 6. A population of 174 DH lines was characterized for important aspects of PHS including sprouting index, germination index, Hagberg falling number and seed coat colour. A total of 11 QTLs were identified on group 3 chromosomes and on chromosome 5D. Seven QTLs associated with the PHS traits were found to be co-incident with seed coat colour on chromosomes 3A, 3B and 3D. The 5D PHS QTL was notable because it is independent of seed coat colour.     

QTL analysis of seed dormancy in rice (Oryza sativa L.)

Effective cumulative temperature (ECT) after heading would be a more reasonable parameter for seed sampling of pre-harvest sprouting/seed dormancy (SD) tests in segregating populations than the days after flowering. SD is an important agronomic trait associated with grain yielding, eating quality and seed quality. To identify genomic regions affecting SD at different grain-filling temperatures, and to further examine the association between SD and ECT during grain-filling, 127 double haploid (DH) lines derived from a cross between ZYQ8 (indica)/JX17 (japonica) by anther culture were analyzed. The quantitative trait loci (QTLs) and their digenic epistasis for SD were identified using a molecular linkage map of this population. A total of four putative QTLs for SD (qSD-3, qSD-5, 6 and 11) were detected on chromosomes 3, 5, 6 and 11, together explaining 41.4% of the phenotypic variation. Nine pairs of digenic epistatic loci were associated with SD on all but chromosome 9, and their contributions to phenotypic variation varied from 2.87%–8.73%. The SD QTL on chromosome 3 was identical to the QTLs found in other mapping populations with different genetic backgrounds, which could be a desirable candidate for gene cloning and marker-assisted selection in rice breeding.     

甘蓝型油菜产量及相关性状的QTL分析

高产是甘蓝型油菜育种的重要目标之一，产量是多基因控制的数量性状。本文通过QTL作图分析了产量及其相关性状的数量性状位点，以甘蓝型油菜中油821和保604 F₁代小孢子培养获得的DH系为作图群体，构建了由20个连锁群组成的，包括251个分子标记( 2个RFLP标记，72个RAPD标记，91个SSR标记，86个SRAP标记)的遗传连锁图(10个标记没有分配到连锁群中)。图谱的平均图距为6.96 cM，共覆盖油菜基因组1 746.5 cM。在此图谱基础上采取复合区间作图法，检测到与油菜产量及其相关性状有关的QTL共17个。其中控制株高的3个分别位于第4、第9和第10连锁群上，对性状的解释率为9.42%～17.58%；与分枝部位有关的4个分别位于第4、第6和第7连锁群上，其中Bp1 和Bp2 均位于第4连锁群，对性状的解释率为8.13%～15.20%；与主花序有效长有关的3个分别位于第4、第10和第16连锁群上，对性状的解释率为7.49%～23.36%；与一次有效分枝有关的2个分别位于第1、第4连锁群上，对性状的解释率为15.29%～19.58%；与角果总数和千粒重有关的分别位于第4连锁群和第9连锁群上，贡献率分别为17.42%和7.64%；与单株产量有关的3个分别位于第3、第4和第15连锁群，共解释26.60%的表型变异。部分性状的QTL在连锁群上成簇分布,对性状贡献率很大，表现主效QTLs的特点，相应的性状之间也呈显著相关，这表明一因多效或者相关的QTLs之间紧密连锁是性状相关的遗传基础。本研究中与主效QTLs连锁的标记可用于油菜产量性状的分子标记辅助选择。     

稻米直链淀粉含量基因座位的分子标记定位

以直链淀粉含量(AC)中等的CT9993和泰国优质的香软米KDML105杂交产生的152个重组近交系 (RIL)为材料, 构建了含83个RFLP、 69个AFLP和15个微卫星(SSLP)标记的分子标记连锁图 , 标记间平均距离为12.98 cM。 应用该连锁图对控制稻米AC的基因座位(QTL)进行了分析 。 结果表明： 稻米AC主要受两个主效QTL和5个微效QTL的共同控制     

Molecular genetic analysis of flour color using a doubled haploid population in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Flour color is an important trait in the assessment of flour quality for the production of many end products. In this study, quantitative trait loci (QTLs) with additive effects, epistatic effects, and QTL × environment (QE) interactions for flour color in bread wheat (Triticum aestivum L.) were studied, using a set of 168 doubled haploid (DH) lines derived from a Huapei 3 × Yumai 57 cross. A genetic map was constructed using 283 simple sequence repeats (SSR) and 22 expressed sequence tags (EST)-SSR markers. The DH and parents were evaluated for flour color in three environments. QTL analyses were performed using QTLNetwork 2.0 software based on a mixed linear model approach. A total of 18 additive QTLs and 24 pairs of epistatic QTLs were detected for flour color, which were distributed on 19 of the 21 chromosomes. One major QTL, qa1B, closely linked to barc372 0.1 cM, could account for 25.64% of the phenotypic variation of a* without any influence from the environments. So qa1B could be used in the molecular marker-assisted selection (MAS) in wheat breeding programs. The results showed that both additive and epistatic effects were important genetic basis for flour color, and were also sometimes subject to environmental modifications. The information obtained in this study should be useful for manipulating the QTLs for flour color by MAS in wheat breeding programs. Kun-Pu Zhang and Guang-Feng Chen contributed equally to this study.     

利用DH群体动态检测水稻抗褐飞虱数量性状基因位点

利用籼粳交珍汕97／武育粳2号F1花培获得的190个双单倍体群体(doubled—haploid population,DH系)及其构建的179个SSR分子标记遗传图谱,通过对DH系群体苗期重复接虫试验和2个不同时期对褐飞虱危害程度进行动态调查,并应用Mapmaker／exp Version3．0和Windows QTL Cartographer V2．0对水稻抗褐飞虱数量性状基因位点(quantative trait locus,QTL)进行动态检测和遗传效应分析。结果表明,在苗期对褐飞虱抗性的检测中,共检测到6个抗性QTL,分别位于第2、3、4、8和10染色体上,各QTL的LOD值分别为2．22-4．64,贡献率为5．04％～13．73％,第3染色体和第4染色体上各有1个OTL的加性效应为正值,表明来自于亲本武育粳2号的这2个位点的等位基因可以提高水稻对褐飞虱的抗性,其余4个QTL的加性效应均为负值,表明来自于亲本珍汕97的这些位点的等位基因可以提高水稻对褐飞虱的抗性。     

QTL-based analysis of heterosis for number of grains per spike in wheat using DH and immortalized F 2 populations

To map quantitative trait loci (QTL) and heterotic loci (HL) related to grain number per spike (GNS), 168 double haploid (DH) populations derived from Huapei?3?×?Yumai?57 and an immortalized F ₂ population (IF ₂) generated by randomly permutated intermating of these DH populations were investigated. Using inclusive composite interval mapping (ICIM), a total of nine and eight significant QTLs for GNS were detected in three different environments in DH and IF ₂ populations, respectively. QTLs on chromosomes?1A, 2B, 3B, and 6A were observed between two populations. Five QTLs were detected on chromosome?1A. Of these QTLs, QGns1A-1 was a major QTL explaining 31.25?% of phenotypic variation. QGns2B-2 detected on chromosome?2B had the most significant additive effects, explaining 46.75?% of phenotypic variation with the favorable allele contributed by Yumai?57 corresponding to an increase of 5.69?kernels. Mid-parent heterosis of each cross in the IF ₂ population was used to map heterotic quantitative trait loci. A total of 17 HLs were detected. QTLs and HLs on chromosomes?2B and 6A were observed in the IF ₂ population. Three HLs, QHgns1B-2, QHgns2B, and QHgns6A-1, were detected in two environments and expressed stably. These results showed that some intervals on chromosomes?1B, 2B, and 6A play an important role in GNS heterosis in wheat, improving understanding of this phenomenon.     

向日葵高密度遗传连锁图谱构建及两种水分条件下芽期性状的QTL分析

干旱胁迫对向日葵发芽出苗有重要影响。以K55×K58组合衍生的187个F6重组自交系为材料,利用SSR、SRAP、AFLP标记构建向日葵高密度遗传连锁图谱,设置正常水分(CK)和模拟干旱(18%聚乙二醇PEG-6000)两种水分条件,调查9个芽期数量性状,PCR扩增株系,构建一张包含17个连锁群、1105个标记(368个SSR、368个SRAP和369个AFLP)的高密度遗传连锁图谱。该图谱覆盖基因组长度3846.0 c M,平均图距3.48 c M,连锁群长度147.6~295.5 c M,每个连锁群标记数10~165个。两种条件下检测到33个QTL,其中干旱条件下检测到发芽指数、发芽率、胚芽长、胚根长、胚芽鲜重和胚根鲜重6个性状的14个QTL,可解释6.1%~14.0%的表型变异;正常水分(CK)条件下检测到发芽势、胚根长、胚芽鲜重、胚根鲜重、胚根干重和胚芽干重6个性状的19个QTL,可解释6.1%~25.8%的表型变异。两种水分条件下检测到Qefw5-1、Qefw5-2、Qefw5-4、Qrfw5、Qrfw10和Qrl9共6个QTL的遗传贡献率超过10%,此外,还检测到9个影响干旱胁迫与正常水分条件下性状差值的QTL,可能对抗旱性有直接贡献。这些QTL可为向日葵芽期抗旱分子设计育种研究提供重要参考。     

大豆不同生育时期叶绿素含量QTL的定位及其与产量的关联分析

利用来自波高×南农94-156的151个RI家系检测与4个不同生育时期叶绿素含量（累积量、净增量）有关的QTL,并分析其与籽粒产量、表观生物学产量和表观收获指数的关系。结果表明,与叶绿素累积量有关的QTL位于D1a+Q、F、G、H、L和M连锁群上,每个QTL可解释表型变异的6.9%~23.4%。V6和R2期没有检测到2个年份均表达的QTL,而在R4期检测到4个在2个年份均表达的QTL（qccF.1、qccG.2、qccH.1和qccM.1）,R6期仅检测到1个QTL（qccH.1）在2个年份均表达,该QTL在R4也表达。与叶绿素含量净增量有关的QTL位于B2和L连锁群上,在V6-R2时期没有检测到与叶绿素净增量有关的QTL,在B2和L连锁群上的两个QTL（qccB2-1.1和qccL.1）在R2-R4和R4-R6时期均表达,qccB2-1.1可解释表型变异的6.4%~9.8%,而qccL.1所解释表型变异达29.5%~31.3%。但这两个QTL在R2-R4和R4-R6时期表达的性质不同,且与2年均表达的籽粒产量QTL共位。这印证了生育后期叶绿素含量与籽粒产量间存在的极显著正相关。