利用永久F2群体定位小麦株高的QTL

为研究小麦株高的遗传机制,利用DH群体构建了一套包含168个杂交组合的小麦永久F₂群体, 并于2007年种植于山东泰安和山东聊城。构建了一套覆盖小麦21条染色体的遗传连锁图谱并利用该图谱的324个SSR标记对小麦株高进行QTL定位研究,使用基于混合线性模型的QTLNetwork 2.0软件进行QTL分析。在永久F₂群体中定位了7个株高QTL,包括4个加性QTL,一个显性QTL,一对上位性QTL,共解释株高变异的20%,其中位于4D染色体的qPh4D,具有最大的遗传效应,贡献率为7.5%;位于2D 染色体显性效应位点qPh2D,可解释1.6%的表型变异;位于5B~6D染色体上位效应位点,可解释1.7%的表型变异。还发现加性效应、显性效应和上位效应对小麦株高的遗传起重要作用,并且基因与环境具有互作效应,结果表明利用永久F₂群体进行QTL定位研究的方法有助于分子标记辅助育种。     

小麦白粉病成株抗性和抗倒伏性及穗下节长度的QTL定位

由小麦品种花培3号和豫麦57杂交获得了DH群体168个株系, 利用305个SSR标记对白粉病成株抗性、抗倒伏性和穗下节长度进行了QTL定位研究。DH群体及两亲本于2005年和2006年种植于山东泰安, 2006年种于安徽宿州。利用基于混合线性模型的QTLNetwork 2.0软件, 共检测到12个加性效应位点和10对上位效应位点。在4D染色体上控制白粉病成株抗性的qApr4D, 贡献率为20.0%, 在各环境中稳定表达, 其抗病等位基因来源于抗病亲本豫麦57; 在7D染色体上控制小麦穗下节长度的qIlbs7D, 贡献率为12.9%, 在各环境中稳定表达。加性效应和上位效应对小麦白粉病成株抗性、抗倒伏性和穗下节长度的遗传起重要作用, 并且基因与环境常常具有互作效应。以上两个QTL可分别用于小麦白粉病成株抗性和穗下节长度的分子标记辅助选择。     

利用“永久F2”群体进行小麦幼苗根系性状QTL分析

为了研究小麦苗期根系性状的遗传,以小麦品种花培3号和豫麦57的杂交DH群体组配了一套含168个杂交组合的“永久F₂”群体。利用WinRHIZO根系分析系统测定四叶一心期小麦水培幼苗根系总长度、直径、表面积、体积、根尖数、最大根长、茎叶干重、根干重及根茎干重比9个性状。采用复合区间作图法分析幼苗根系8个性状的QTL,定位了7个加性效应QTL和12对上位性互作QTL,包括加性效应、显性效应,加加互作、加显互作和显显互作,分布在1A、1D、2A、2B、2D、3A、3B、5D、6D和7D染色体上,单个QTL可解释0.01%~11.91%的遗传变异。在染色体2D上XWMC41至XBARC349.2区间检测到同时控制总根长和根干重的一个QTL。上位性对苗期根系生长发育有重要作用。试验结果表明,苗期根系性状的遗传机制较复杂, 因此在育种中要综合考虑根系各性状之间的关系,保证根系协调统一、发达健壮。     

小麦穗部性状和株高的QTL定位

穗粒数是小麦的重要产量性状之一,减少基部不育小穗数是提高小麦穗粒数的重要途径。利用EMS诱变小麦品系山农1186获得基部2-4个小穗不育突变体M7652。本研究利用M7652与山农1186回交获得的BC3F2群体及其衍生的BC3F2:3株系(MS)群体,M7652与泰农18杂交获得的F2群体及其衍生的F2:3株系(MT)群体为材料,进行遗传作图和QTL定位。通过SSR标记检测构建了分别覆盖38.9 c M、73.1 c M的两个4B染色体的遗传连锁图。对两个群体的穗部性状和株高进行QTL分析表明,MS回交群体在3个环境下都检测到6个QTL,包括5个控制穗部性状和1个株高性状的QTL位点,其贡献率为18.22%~47.23%,且位于染色体的相同区段,形成一个QTL簇;MT群体在1个环境中检测到4个控制穗部性状、1个控制株高的QTL位点,其贡献率为1.51%~39.15%,形成一个QTL簇。利用MS和MT群体检测到的QTL簇在染色体上的位置相同,都覆盖swes24标记,这个区域与增加小麦穗粒数、降低株高有关,为小麦穗粒数、株高的精细定位、基因克隆奠定了基础。     

水稻不育系抽穗包颈性状的遗传研究

为了探讨水稻不育系抽穗包颈性状的遗传基础,且为选育不包颈或包颈轻的不育系提供依据,本研究利用W9593S(抽穗包颈轻)与培矮64S(抽穗包颈重)2个光温敏核不育系杂交、回交构建遗传群体,采用植物数量性状主基因+多基因混合遗传体系的6世代联合分离分析方法,剖析了水稻不育系抽穗包颈性状的遗传模型,并与F2群体QTL定位结果进行比较分析。结果表明:经分离分析,穗粒外露度、包颈长均表现为B-1模型(2对加性-显性-上位性主基因模型);包颈度、顶1节间长和剑叶鞘长的最适模型分别为D-4(1对负向完全显性主基因+加性-显性多基因遗传模型)、D-1(1对加性-显性主基因+加性-显性多基因遗传模型)和C-0模型(加性-显性-上位性多基因遗传模型)。对F2分离群体进行QTL定位,共检测到分别与穗粒外露度、包颈长、包颈度、顶1节间长和剑叶鞘长有关的25个QTL,分布于第1、第2、第4、第5、第6、第7和第12染色体上,表型贡献率变幅为2.85%~16.73%。其中位于第12染色体与SSR标记RM3331连锁的QTL以及位于第6染色体分别与SSR标记RM439和RM3765连锁的QTL均同时影响穗粒外露度、包颈长和包颈度3个性状,位于第4染色体分别与SSR标记RM255和RM3687连锁的QTL同时影响顶1节间长和剑叶鞘长2个性状,这5个QTL位点可能是调控不育系抽穗包颈性状的重要位点。QTL定位结果与6世代分离分析结果在某种程度上具有相似性,又不完全一致,可能与这两种方法依据的遗传群体不同以及数量性状受环境影响较大有关。     

水稻株高QTL分析及其与产量QTL的关系

分别应用具有112和160个标记位点的两个籼/籼交组合的F2群体的连锁图,对控制水稻株高的数量性状基因(QTL)进行了研究.各定位了4个和3个株高QTL,每个QTL的贡献率在5.6%～22.9%之间.在一个群体中,4个QTL都表现为完全显性或超显性;在另一个群体中,3个QTL均表现为部分显性.分别检测到7对和5对影响株高的双基因互作,其中一个群体以     

调控小麦重要农艺性状基因的染色体定位

为了研究调控小麦重要农艺性状基因的染色体分布,进一步解析控制小麦重要农艺性状基因的遗传基础,本研究以一套"中国春-人工合成小麦"染色体代换系为材料,在大田条件下,对不同株系小麦的株高、穗长和穗数等重要农艺性状进行调查。通过同一性状不同株系间的差异显著性分析,对调控株高、穗长和穗数的基因进行了染色体定位。研究结果表明:1 B、2 B、3 A、4 A、6 A、6 D和7 D染色体上可能携带有调控小麦株高的位点;1 B、1 D、2 B、2 D、5 A、6 A、6 D和7 D染色体上可能携带有调控小麦穗长的基因位点;3 A和6 D染色体上可能携带有调控小麦成穗数的位点。本研究有利于进一步理解调控小麦农艺性状的遗传基础,并对小麦分子育种实践具有一定的指导意义。     

小麦胚芽鞘长、幼苗根长的QTL定位

小麦品种花培3号和豫麦57构建的DH群体的168个株系及亲本为材料,在正常发芽和20%PEG-6000模拟水分胁迫处理条件下测定小麦幼苗的胚芽鞘长、根长。利用完备区间作图法分析幼苗胚芽鞘长、幼根长的QTL。两种处理条件下共定位了8个控制胚芽鞘长加性QTL,其中位于染色体2A、4B和4D上的QCl2A、QCl4B和QCl4D在两种处理条件下均被检测到,可解释6.10%～16.31%的表型变异。两种条件下共定位了10个控制幼根长加性QTL,其中位于染色体6A上Xgwm82和Xwmc553区间的QRl6A在两种处理下均被检测到,可分别解释8.26%和9.74%的表型变异。在检测到的18对控制胚芽鞘长、根长的上位性互作位点中,大多数互作属于非等位QTL间的非加性QTL位点之间互作。因此在小麦材料的早期抗旱性筛选、分子育种时要同时考虑加性QTL和非加性QTL位点间的上位性互作。     

小麦温敏不育系SCT-1育性基因初步定位分析

为明确小麦温敏不育系SCT-1的育性调控基因数量及位点,本研究以组合SCT-1×B2183的F2群体为材料,选用SSR标记和分离群体分组分析法(BSA)筛选与育性相关的分子标记,用完备区间作图法对育性进行初步QTL定位分析。研究结果显示:在2B染色体上存在2个育性调控QTLs:Qwtms-saas-2B-1(位于Xgwm374-Xgwm388间,LOD值4.521)和Qwtms-saas-2B-2(位于Xgwm388-Xbarc101间,LOD值3.115),对表型的贡献率分别为7.649%和13.865%;在5D染色体上检测到1个主效QTL Qwtms-saas-5D-1(位于Xcfd26-Xcfd29间,LOD值11.101),其贡献率达28.093%。研究表明,Qwtms-saas-2B-1与Qwtms-saas-5D-1在成都和新都均能检测到,是育性调控较为可靠的位点。本研究初步定位小麦温敏不育系SCT-1在2B和5D上的育性调控QTLs,可为进一步精确定位奠定基础。     

小麦新种质N95175抗白粉病基因的SSR分析

为明确小簇麦新种质N95175抗白粉病基因的遗传效应和基因位点,采用常规分析法结合SSR技术进行抗性基因的遗传分析和分子标记研究。抗性基因常规分析结果表明,N95175分别与高感白粉病普通小麦品种陕160和陕优225两个杂交组合的F1均现高抗,F2抗感植株比例分别为115∶43和111∶48,经χ2检验,符合3∶1的显性单基因孟德尔遗传分离比例,即该抗白粉病基因为显性单基因遗传。利用208对小麦微卫星引物对N95175×陕优225的F2抗感分离群体分析结果表明,Xgwm570和Xwmc553均与抗白粉病基因连锁,遗传距离分别为13.38和12.03 cM。Xg-wm570和Xwmc553两者之间在两群体中的遗传距离为3.74 cM。利用两引物对N95175×陕160组合F2代进行标记验证分析,分析结果与接种后调查结果符合率为89.24%。根据Xgwm570和Xwmc553在小麦染色体的位置,将N95175的抗白粉病基因定位在6A染色体上。     

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.     

QTL analysis of textural property traits for Chinese northern-style steamed bread

Quantitative trait loci (QTLs) influencing textural properties (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, and resilience)of wheat for Chinese northern-style steamed bread were studied using a doubled haploid (DH) population containing 168 lines derived from a cross between elite Chinese wheat cultivars Huapei 3 and Yumai 57 (Triticum aestivum L.). The DH population and parents were grown in 2007 and 2008 in Tai’an and 2008 in Suzhou. QTL analyses were performed using the software QTL Network version 2.0 and IciMapping v2.2 based on the mixed linear model. Thirty nine putative QTLs were detected on 14 chromosomes: viz. 1A, 2A, 3A, 4A, 6A, 1B, 2B, 3B, 5B, 6B, 7B, 5D, 6D, and 7D, and single QTLs explained 3.91–35.17% of the phenotypic variation. Eight pairs of QTLs with epistatic effects and/or epistasis × environment (AAE) effects were detected for adhesiveness, resilience, hardness, and cohesiveness on chromosomes 2A, 1B and 3D. Several co-located QTLs with additive effects were detected on chromosomes 2B, 5D, 6A, 3A, 3B and 6D. Two clusters of three QTLs for steamed bread textural properties (chewiness, gumminess, and hardness) and for adhesiveness, cohesiveness and resilience were detected on chromosome 2B. Two co-located QTLs with epistatic effects were detected on chromosomes 1B and 3A. Both additive effects and epistatic effects were important for Chinese steamed bread textural properties, which were also subject to environmental modifications. The information obtained in this study will be useful for manipulating QTLs determining Chinese steamed bread textural properties by molecular marker-assisted selection.     

基于QTL定位的蓖麻株高性状遗传解析

用YC2(高杆)×YF1(矮杆)和YC1(高杆)×YF1(矮杆)组合衍生的2个F₂代群体, 对蓖麻株高性状进行相关、回归和QTL定位分析。结果表明, 株高与主穗位高、主茎节长和主茎茎粗之间显著正相关, 但与主茎节数不相关;主穗位高与主茎节数、主茎节长和主茎茎粗之间显著正相关;主茎节数与主茎节长之间显著负相关。利用QTLNetwork 2.0软件在YC2×YF1的F₂群体中检测到株高、主穗位高、主茎节数、主茎节长和主茎茎粗的5、4、6、3和2个QTL, 分别解释了45.9%、45.3%、66.1%、55.4%和12.6%的总变异。在YC1×YF1的F₂群体中检测到3、4、5、1和2个上述5性状的QTL, 分别解释了26.0%、25.5%、35.4%、37.4%和7.6%的总变异。证明QTL间的“一因多效”和连锁是株高、主穗位高和主茎节长之间高度相关的遗传基础, 加性效应是株高、主穗位高和主茎节长的主要遗传组分, 互作效应是主茎节数和主茎茎粗的主要遗传组分。建议育种上将主穗位高和主茎节长作为株高早期选择和预测的间接指标,并将多节数和短节间作为高产育种的主攻方向。     

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.     

Effects of environment, disease progress, plant height and heading date on the detection of QTLs for resistance to Fusarium head blight in an European winter wheat cross

In order to characterise quantitative trait loci (QTLs) for Type I and Type II resistance against Fusarium head blight (FHB) in wheat, a population of recombinant inbred lines derived from the cross Cansas (moderately resistant)/Ritmo (susceptible) was evaluated in spray-inoculated field trials over three seasons. Map-based QTL analysis across environments revealed seven QTLs on chromosomes 1BS, 1DS, 3B, 3DL, 5BL, 7BS and 7AL (QFhs.whs-1B, QFhs.whs-1D, QFhs.whs-3B, QFhs.whs-3D, QFhs.whs-5B, QFhs.whs-7A, QFhs.whs-7B) associated with FHB resistance. They accounted for 56% of the phenotypic variance. QFhs.whs-1D primarily appeared to be involved in resistance to fungal penetration, whereas the other QTLs mainly contributed to resistance to fungal spread. FHB resistance was significantly correlated with plant height (PH) and heading date (HD). Including all single environments, corresponding overlaps of QTLs for FHB resistance and QTLs for PH/HD occurred at six loci, among them two consistently detected QTLs, QFhs.whs-5B and QFhs.whs-7A. When significant effects of PH and HD on FHB resistance were eliminated by covariance analysis, a second QTL analysis revealed possible escape mechanisms for the majority of the coincidental loci.     

QTL mapping for developmental behavior of plant height in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

A recombinant inbred line (RIL) population with 305 lines derived from a cross of Hanxuan 10 × Lumai 14 was used to identify the dynamic quantitative trait loci (QTL) for plant height (PH) in wheat (Triticum aestivum L.). Plant heights of RILs were measured at five stages in three environments. Total of seven genomic regions covering PH QTL clusters on different chromosomes identified from a DH population derived from the same cross as the RIL were used as the candidate QTLs and extensively analyzed. Five additive QTLs and eight pairs of epistatic QTLs significantly affecting plant height development were detected by unconditional QTL mapping method. Six additive QTLs and four pairs of epistatic QTLs were identified using conditional mapping approach. Among them, three additive QTLs (QPh.cgb-1B.3, QPh.cgb-4D.1, QPh.cgb-5B.2) and three pairs of epistatic QTLs (QPh.cgb-1B.1–QPh.cgb-1B.3, QPh.cgb-2A.1–QPh.cgb-2D.1, QPh.cgb-2D.1–QPh.cgb-5B.2) were common QTLs detected by both methods. Three QTLs (QPh.cgb-4D.1, QPh.cgb-5B.3, QPh.cgb-5B.4) were expressed under both drought and well-water conditions. The present data are useful for wheat genetic manipulations through molecular marker-assisted selection (MAS), and provides new insights into understanding the genetic mechanism and regulation network underlying the development of plant height in crops. Our result in this study indicated that combining unconditional and conditional mapping methods could make it possible to reveal not only the stable/conserved QTLs for the developmental traits such as plant height but also the dynamic expression feature of the QTLs.     

不同盐浓度胁迫下小麦苗期苗高和主根长的QTL分析

小麦苗期苗高和主根长是鉴定小麦苗期耐盐性的重要指标。利用小麦品种花培3号×豫麦57获得的DH群体168个株系,在去离子水(对照)以及50,100,200 mmol/L NaCl溶液处理下,进行苗高和主根长的数量性状基因(QTL)定位分析。利用完备区间作图法,共检测到影响苗高和主根长的25个QTL,单个QTL对表型的贡献率为4.19%～23.72%。位于3D染色体区间Xgdm72-Xbarc1119上影响主根长的QTL位点具有最大的遗传效应,贡献率为23.72%;在100 mmol/L和50 mmol/L NaCl处理下,在2D染色体Xwmc170.2-Xgwm539区段,同时检测到影响苗高的2个QTL位点,其贡献率分别为12.59%和8.40%;在100 mmol/L和200 mmol/L NaCl处理下,在4D染色体Xc-fa2173-Xcfe188区段,同时检测到影响主根长的2个QTL位点,其贡献率分别为8.77%和5.70%;在对照和100mmol/L NaCl溶液处理下,在5BL染色体Xgwm213-Xswes861.2区段,同时检测到影响苗高的QTL位点,其贡献率分别为17.49%和6.28%。另外,在50 mmol/L NaCl溶液处理下,4B染色体Xwmc657-Xwmc48区段还定位了1个影响苗高的QTL位点,其贡献率为12.59%;在染色体3A和染色体7D上各检测出与主根长有关的1个不同的QTL;在5A染色体Xbarc358.2-Xgwm186和Xcwem40-Xbarc358.2区间分别检测到1个影响苗高的QTL。这些主效QTL可用于苗高和主根长的分子标记辅助选择。     

Identification and application of major quantitative trait loci for panicle length in rice (Oryza sativa) through single‐segment substitution lines

Panicle length (PL), an important yield‐related trait, strongly affects yield components, such as grain number, grain density and rice quality. More than 200 panicle length quantitative trait loci (PL QTLs) are identified, but only a small number are applied in rice breeding. In this study, we performed QTL analysis for PL using 42 single‐segment substitution lines (SSSLs) derived from nine donors in the genetic background of HJX74. Fourteen QTLs and five heterosis QTLs (HQTLs) for PL were recognised. Three QTLs and four HQTLs acted positively, and the other eleven QTLs and one HQTL acted negatively. By scanning the single heterozygous background region of the F₂ population with large‐genetic‐effect SSSLs, we mapped PL loci qPL6‐2 and qPL7‐1 to different locations on chromosomes 6 and 7, respectively, in three consecutive years of independent trials. The genetic effects of these QTLs were further assessed. qPL6‐2 demonstrated the most positive additive effect (QTL), whereas qPL7‐1 achieved the most positive dominant effect (HQTL) for PL. These results indicated that the pyramiding of PL QTLs might increase grain yield and facilitate the application of the beneficial allele in hybrid rice breeding.