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1.
不同水层下水稻对无芒稗的干扰控制作用研究表明,水稻化感作用品种吓一跳、谷梅2号和中156对无芒稗的株高抑制作用比无化感作用品种秀水63和春江11呈显著性差异.随盆栽水稻密度增加,水稻对无芒稗的干扰控制作用加大.在每盆4株栽植密度下,水稻化感作用品种鸡早籼、谷梅2号显著抑制无芒稗植株株高;在每盆32株密度时,水稻化感作用品种吓一跳、PI312777、TN1等对受控无芒稗的干扰控制与无化感作用品种春江11相比,呈显著性水平.  相似文献   

2.
水稻种子活力QTL定位及上位性分析   总被引:6,自引:1,他引:5  
利用1个粳/籼交来源(Lemont/Teqing)、包含264个重组自交系的作图群体,采用纸卷法在18℃培养箱中进行2次重复的发芽实验,考察了种子发芽7d、9d和1ld的发芽率,种子发芽15d后的芽长及干重等种子活力的相关性状。结合一张含有198个DNA标记的连锁图谱,用作图软件QTLMapper1.0定位与种子活力相关的QTL。共检测到13个主效应QTL,这些QTL对性状的贡献率为2.9%~12.7%,平均贡献率为6.2%。同时检测到18对贡献率≥5%的互作位点,其贡献率为5.1%~11.8%,平均贡献率为6.9%,比检测到的主效应QTL的平均贡献率稍大。种子活力相关性状的大多数主效应和互作QTL成串分布于少数几个染色体区段(Chromosome Regions,CRs),并且成串分布在同一染色体区段的QTL效应的方向总是一致,该结果与这些性状在表型上的正相关相一致。若将成串分布有3个及3个以上种子活力相关性状QTL的CRs视为与种子活力高度相关的CRs,则共检测到7个上述与种子活力高度相关的CRs,分别分布在水稻12条染色体中的7条染色体上。根据所含QTL的种类(主效应QTL或/和上位性QTL)可将这些CRs分成以下3种:1)M-CRs:只含有主效应QTL,如CR^sv-7;2)E-CRs:所含位点没有主效应,但与其他位点发生互作,如CR^sv-1、CR^sv-6和CR^sv-12;3)ME-CRs:既含有主效应QTL、也含有与其他位点产生互作的互作位点,如CR^sv-2、CR^sv-5和CR^sv-8。另外还发现,有的CR上的位点同时与多个不同CR上的位点互作,影响种子活力的相关性状。与前入的研究结果相比较,发现有些与种子活力高度相关的CR可在不同研究者所用的不同定位群体中被检测到,而有的CR只在特定的定位群体中被检测到。由此表明,水稻种子活力具有丰富的遗传多样性和复杂的遗传基础,其主效QTL和互作位点可能基于遗传背景的不同而相互转化。  相似文献   

3.
拔节期与抽穗期玉米抗纹枯病相关QTL的初步定位   总被引:4,自引:0,他引:4  
以玉米自交系R15(抗)×478(感)的F_2分离群体为作图群体,构建了包含146个SSR标记位点的遗传连锁图谱,覆盖玉米基因组1666 cM,平均图距11.4 cM。通过麦粒嵌入法对229个F_(2:4)家系进行人工接种纹枯病菌,于玉米拔节期和抽穗期进行纹枯病的抗性鉴定。应用复合区间作图法分析两个时期的抗病QTL及遗传效应。结果共检测到17个抗性QTL,其中以拔节期病情指数为指标共检测到9个QTL,分别位于第1、2、3、4、5、6、和10染色体上,可解释的表型变异为3.72%-9.26%;以抽穗期的病情指数为指标共在7条染色体上检测到10个抗玉米纹枯病的QTL,分布于第2、3、4、5、6、8和9染色体上。单个QTL可解释的表型变异为4.27%-9.27%。两个时期共检测出2个共同QTL,它们分别位于第2染色体的bnlgl662-bnlg1940区间和第6染色体的umc1006-umc1723区间。定位结果表明两个时期检测出的抗性QTL的差异表达与玉米不同发育时期基因的时空表达有密切关系,从而反映在纹枯病的抗性位点差异性上.这为玉米抗病选育提供新的信息。  相似文献   

4.
利用相同遗传背景不同株形水稻浙辐802等基因系为材料,研究了IG1、IG4、IG25和IG26与无芒稗的竞争和化感作用潜力,探索了二者之间的相互关系.结果表明,IG1和IG4的植株高度和分蘖角度显著大于IG25和IG26,但它们的根系活力却显著小于IG25和IG26.IG1和IG4对无芒稗生物量干重抑制率分别达到15%和17%,显著高于IG26的64%,表明水稻与无芒稗竞争力与水稻植株高度和分蘖角度成正比,而与水稻根系活力成反比.IG1叶片水浸提液对无芒稗根长抑制率为776%,显著高于非化感对照品种秀水63,而植株形态相近的IG4的化感作用却未达到显著水平,显示在相同遗传背景下水稻化感作用强弱与水稻株型无相关性.  相似文献   

5.
水稻光合功能相关性状QTL分析   总被引:7,自引:0,他引:7  
利用粳稻Kinmaze/籼稻DV85杂交后代单粒传衍生的81个F11家系所组成的重组自交系(Recombinant Inbred Lines,RILs)群体,研究水稻光合功能相关性状的数量性状基因座(QTL)。在水稻抽穗后7d测定叶片全氮含量(TLN)、叶绿素a/b比值(Chl.a:b)和叶绿素含量(Chl)。共检测到6个QTL,各QTL的LOD值为2.66~4.81,贡献率为11.2%-29.6%,其中,在第1、2和11染色体上检测到3个与全氮含量相关的QTL,相应贡献率为17.3%、15.3%、13.7%;在第3和4染色体检测到2个与叶绿素a/b比值相关的QTL,贡献率为13.8%和29.6%;在第1染色体检测到1个与叶绿素含量相关的QTL,贡献率为11.2%。4个QTL为本研究新检测的基因座。有趣的是,控制叶绿素含量的qCC-1位于第1染色体上RFLP标记C122附近,与已报道的NADH-谷氨酸合成酶基因位置一致,而叶绿素合成始于谷氨酸,暗示该基因座与水稻光合功能关系极为密切。然而,对抽穗后30d叶绿素含量进行QTL分析,结果未检测到与其相关的QTL,表明控制叶绿素含量qCC-1效应随水稻叶片的衰老而降低。  相似文献   

6.
锌元素的营养失衡已成为影响人类健康的最重要因素之一,籽粒锌含量的QTL(quantitative trait loci)定位对研究富锌水稻的遗传育种具有重要的意义。以水稻(Oryzasativa L.)亲本奉新红米和明恢100杂交的145个株系的F2群体为实验材料,利用92个SSR(simple sequence repeat)标记对水稻籽粒锌含量进行了QTL定位,共检测到3个QTLs,分别定位于第3、6和11染色体上,对表型变异的贡献率分别为4.97%、12.75%和7.74%。其中位于第3染色体上的分子标记RM186和RM168之间的QZN3对表型变异的贡献率最大,其增效等位基因来自亲本明恢100,表现为部分显性。3个QTLs的联合贡献率为25.46%。具有基因累加效应。该研究结果有利于深入理解水稻锌含量的遗传基础,为锌含量的QTL精细定位、基因克隆和分子标记辅助选择提供依据。  相似文献   

7.
潜育性水稻田广泛分布于中国、斯里兰卡、印度、印度尼西亚、塞拉里昂、利比亚、尼日利亚、哥伦比亚和菲律宾等国,其中我国南方稻区就有近700万公顷低产潜育性水稻田。该类水稻田还原性强,矿质营养失调,尤以Fe^2 过量积累,对水稻生长发育产生不良的逆境胁迫作用。培育抗亚铁毒的水稻品种是简便、经济有效地提高稻谷产量的重要途径之一。该文利用由粳稻品种Asominori与籼稻品种IR24杂交衍生的Asominori染色体片段置换系(Chromosome Segment Substitution Lines,CSSLs)群体为材料,检测与抗亚铁毒胁迫有关性状QTL。共检测到与抗亚铁毒胁迫有关性状QTL14个,各QTL的LOD值为2.72~6.63。其中检测到与抗亚铁毒胁迫直接有关的性状叶片棕色斑点指数QTL3个,分别位于第3、9、11染色体C515~XNpb279、R2638~C1263和G1465~C950之间,对应的贡献率分别为16.45%、11.16%和28.02%;与其他已发表的定位结果比较发现,位于第三染色体C515~XNpb279间控制叶片棕色斑点指数的QTL与水稻功能图谱上控制叶绿素含量的QTL的位置一致;表明在亚铁毒胁迫条件下,水稻在其叶片表面出现棕色斑点,叶片衰老,产生一些叶绿素降解物或衍生物,以提高叶片细胞对亚铁等重金属毒害的耐受力。另外,在第11染色体G1465~C950之间检测到了控制叶片棕色斑点指数、茎干重和根干重QTL1个,为主效QTL。在第6染色体XNpb386~XNpb342之间检测到控制茎干重、株高、根长和根干重QTL1个,是否与水稻抗亚铁毒有关需要进一步研究。本研究旨在通过定位与抗亚铁毒有关的QTL,借助与之紧密连锁的分子标记有效地聚合这些QTL,培育出抗亚铁毒性强的水稻新种质材料。  相似文献   

8.
直播条件下水稻6个穗部性状的QTL分析   总被引:2,自引:0,他引:2       下载免费PDF全文
在大田直播条件下,利用来源于"Lemont/特青"的重组自交系群体,对水稻6个穗部性状及其相互间遗传相关的分子基础进行了QTL分析,共检测到19个QTL,各性状QTL数为2~4个,单个QTL贡献率为4%~22%。共检测到3个染色体区段能同时影响多个穗部性状,其中第1染色体RM212-RM104和第2染色体RM263-RM221区段的QTL能同时影响单株产量、每穗颖花数、着粒密度和二次枝梗数中的3个或4个性状,且这2个区段的QTL对各性状的效应方向相同,增效等位基因均来自‘特青’,为各性状间表型正相关提供了重要的遗传解释。第11染色体RG1022附近的QTL对着粒密度的效应值为负,来自‘特青’的等位基因增加性状值,而对穗长的效应值为正,来自‘特青’的等位基因降低性状值,为这2个性状间表型负相关也提供了一定的遗传解释。此外,对水稻穗部性状QTL在多种环境和遗传背景下的稳定表达及其在分子标记辅助育种中的应用进行了讨论。  相似文献   

9.
利用水稻重组自交系群体定位谷粒外观性状的数量性状基因   总被引:36,自引:0,他引:36  
用区间作图和混合线性模型的复合区间作图两种方法,对水稻(Oryza sativa L)珍汕97和明恢63组合的重组自交系群体的谷粒外观性状-粒长,粒宽和粒形进行了数量性状基因(QTL)定位,用区间作图法在LOD≥2.4水平上(近拟于a=0.005),1998年对粒长,粒宽和粒形分别检测到6,2放2个QTLs,1999年对以上3个性状分别检测到3,2和2个QTLs,其中7个QTLs在两年均检测到,位于第3染色体RG393-C1087区间的QTL效应大,同时影响粒长和粒形,两年贡献分别为57.5%,61.4%和26.7%,29.9%,位于第5染色体RG360-C734B区间的QTL效应大,同时影响粒宽和粒形,两年贡献率分别为44.2%,53.2%和32.1%和36.0%,用混合线性模型的复合区间作图法在P=0.005水平上,对粒长,粒宽和粒形分别检测到8,5和5个QTLs,共解释各自性状变异的58.81%,44.75%和57.47%,只检测到1个QTL与环境之间存在的显互作。  相似文献   

10.
水稻对叶瘟和穗瘟部分抗性的遗传分析   总被引:1,自引:0,他引:1  
在一个水稻籼籼交重组自交系群体中,选用由感病株系构成的2个亚群体和2个不同的稻瘟病菌小种,进行了水稻对叶瘟部分抗性的QTL定位,还选用由感病而且抽穗期相近的株系构成的亚群体和另一个病菌小种,进行了水稻对穗瘟部分抗性的QTL定位,将病叶面积百分比(DLA)、病斑大小(LS)和病斑数(LN)作为对叶瘟部分抗性的性状,将病斑长度(LL)和孢子量(CA)作为对穗瘟部分抗性的性状。所构建的图谱包含168个标记。应用QTLMapper 1.01b,共检测到11个表现主效应的QTL和28对双因子互作,有3个表现主效应的QTL参与对同一性状的互作。QTL的主效应对单一性状的贡献率为4.7%~38.8%,而上位性效应对单一性状的贡献率为16.0%~51.7%,QTL的主效应对大多数性状的贡献率小于互作效应,表明互作效应对于部分抗性的重要作用。对穗瘟部分抗性的两个性状LL和CA,所检测到QTL总效应的贡献率分别达到70.6%和82.6%,表明由排除了主效抗病基因的感病株系组成的亚群体适合于进行部分抗性QTL定位。  相似文献   

11.
Common smut in maize, caused by Ustilago maydis, reduces grain yield greatly. Agronomic and chemical approaches to control such diseases are often impractical or ineffective. Resistance breeding could be an efficient approach to minimize the losses caused by common smut. In this study, quantitative trait loci (QTL) for resistance to common smut in maize were identified. In 2005, a recombinant inbred line (RIL) population along with the resistant (Zong 3) and susceptible (87-1) parents were planted in Beijing and Zhengzhou. Significant genotypic variation in resistance to common smut was observed at both locations after artificial inoculation by injecting inoculum into the whorl of plants with a modified hog vaccinator. Basing on a genetic map containing 246 polymorphic SSR markers with an average linkage distance of 9.11 cM, resistance QTL were analysed by composite interval mapping. Six additive-effect QTL associated with resistance to common smut were identified on chromosomes 3 (three QTL), 5 (one QTL) and 8 (two QTL), and explained 3.2% to 12.4% of the phenotypic variation. Among the 6 QTL, 4 showed significant QTL x environment (Q x E) interaction effects, which accounted for 1.2% to 2.5% of the phenotypic variation. Nine pairs of epistatic interactions were also detected, involving 18 loci distributed on all chromosomes except 2, 6 and 10, which contributed 0.8% to 3.0% of the observed phenotypic variation. However, no significant epistasis x environment interactions were detected. In total, additive QTL effects and Q x E interactions explained 38.8% and 8.0% of the phenotypic variation, respectively. Epistatic effects contributed 15% of the phenotypic variation. The results showed that besides the additive QTL, both epistasis and Q x E interactions formed an important genetic basis for the resistance to Ustilago maydis in maize.  相似文献   

12.
To identify the genetic background of seminal root length under different water-supply conditions, a recombinant inbred (RI) population consisting of 150 lines, derived from a cross between an indica lowland rice, IR1552, and a tropical japonica upland rice, Azucena, was used in both solution culture (lowland condition) and paper culture (upland condition). Quantitative trait loci (QTLs) and epistatic loci for seminal root length were analyzed using 103 restriction fragment length polymorphism (RFLP) markers and 104 amplified fragment length polymorphism (AFLP) markers mapped on 12 chromosomes based on the RI population. One QTL for seminal root length in solution culture (SRLS) and one for seminal root length in paper culture (SRLP) were detected on chromosomes 8 and 1, and about 11% and 10% of total phenotypic variation were explained, respectively. The QTL for SRLP on chromosome 1 was very similar with the QTL for the longest nodal root referred to in a previous report; this QTL may be phenotypically selectable in a breeding program using paper culture. Five pairs of epistatic loci for SRLS were detected, but only one for SRLP, which accounted for about 60% and 20% of the total variation in SRLS and SRLP, respectively. The results indicate that epistasis is a major genetic basis for seminal root length, and there is a different genetic system responsible for seminal root growth under different water supply conditions. Received: 26 May 2000 / Accepted: 19 October 2000  相似文献   

13.
Quantitative trait loci (QTLs) for plant height in wheat (Triticum aestivum L.) were studied using a set of 168 doubled haploid (DH) lines, which were derived from the cross Huapei 3/Yumai 57. A genetic linkage map was constructed using 283 SSR and 22 EST-SSR markers. The DH population and the parents were evaluated for wheat plant height in 2005 and 2006 in Tai’an and 2006 in Suzhou. QTL analyses were performed using the software of QTLNetwork version 2.0 based on the mixed linear model. Four additive QTLs and five pairs of epistatic effects were detected, which were distributed on chromosomes 3A, 4B, 4D, 5A, 6A, 7B, and 7D. Among them, three additive QTLs and three pairs of epistatic QTLs showed QTL×environment interactions (QEs). Two major QTLs, Qph4B and Qph4D, which accounted for 14.51% and 20.22% of the phenotypic variation, were located similar to the reported locations of the dwarfing genes Rht1 and Rht2, respectively. The Qph3A-2 with additive effect was not reported in previous linkage mapping studies. The total QTL effects detected for the plant height explained 85.04% of the phenotypic variation, with additive effects 46.07%, epistatic effects 19.89%, and QEs 19.09%. The results showed that both additive effects and epistatic effects were important genetic bases of wheat plant height, which were subjected to environmental modifications, and caused dramatic changes in phenotypic effects. The information obtained in this study will be useful for manipulating the QTLs for wheat plant height by molecular marker-assisted selection (MAS).  相似文献   

14.
Quantitative trait loci (QTLs) for plant height in wheat (Triticum aestivum L.) were studied using a set of 168 doubled haploid (DH) lines, which were derived from the cross Huapei 3/Yumai 57. A genetic linkage map was constructed using 283 SSR and 22 EST-SSR markers. The DH population and the parents were evaluated for wheat plant height in 2005 and 2006 in Tai'an and 2006 in Suzhou. QTL analyses were performed using the software of QTLNetwork version 2.0 based on the mixed linear model. Four additive QTLs and five pairs of epistatic effects were detected, which were distributed on chromosomes 3A, 4B, 4D, 5A, 6A, 7B, and 7D. Among them, three additive QTLs and three pairs of epistatic QTLs showed QTLxenvironment interactions (QEs). Two major QTLs, QphAB and Qph4D, which accounted for 14.51 % and 20.22% of the phenotypic variation, were located similar to the reported locations of the dwarfing genes Rhtl and Rht2, respectively. The Qph3A-2 with additive effect was not reported in previous linkage mapping studies. The total QTL ef fects detected for the plant height explained 85.04% of the phenotypic variation, with additive effects 46.07%, epistatic effects 19.89%, and QEs 19.09%. The results showed that both additive effects and epistatic effects were important genetic bases of wheat plant height, which were subjected to environmental modifications, and caused dramatic changes in phenotypic effects. The information obtained in this study will be useful for manipulating the QTLs for wheat plant height by molecular marker-assisted selection (MAS).  相似文献   

15.
In order to explore the relevant molecular genetic mechanisms of photosynthetic rate (PR) and chlorophyll content (CC) in rice ( Oryza sativa L.), we conducted a series of related experiments using a population of recombinant inbred lines (Zhenshan97B × IRAT109). We found a significant correlation between CC and PR ( R = 0.19**) in well-watered conditions, but no significant correlation during water stress ( r = 0.08). We detected 13 main quantitative trait loci (QTLs) located on chromosomes 1, 2, 3, 4, 5, 6, and 10, which were associated with CC, including six QTLs located on chromosomes 1, 2, 3, 4, and 5 during water stress, and seven QTLs located on chromosomes 2, 3, 4, 6, and 10 in well-watered conditions. These QTLs explained 47.39% of phenotypic variation during water stress and 56.19% in well-watered conditions. We detected four main QTLs associated with PR; three of them ( qPR2 , qPR10 , qPR11 ) were located on chromosomes 2, 10, and 11 during water stress, and one ( qPR10 ) was located on chromosome 10 in well-watered conditions. These QTLs explained 34.37% and 18.41% of the phenotypic variation in water stress and well-watered conditions, respectively. In total, CC was largely controlled by main QTLs, and PR was mainly controlled by epistatic QTL pairs.  相似文献   

16.
Test weight is an important trait in maize breeding. Understanding the genetic mechanism of test weight is important for effective selection of maize test weight improvement. In this study, quantitative trait loci (QTL) for maize test weight were identified. In the years 2007 and 2008, a F2:3 population along with the parents Chang7-2 and Zheng58 were planted in Zhengzhou, People’s Republic of China. Significant genotypic variation for maize test weight was observed in both years. Based on the genetic map containing 180 polymorphic SSR markers with an average linkage distance of 11.0 cM, QTL for maize test weight were analysed by mixed-model composite interval mapping. Five QTL, including four QTL with only additive effects, were identified on chromosomes 1, 2, 3, 4 and 5, and together explained 25.2% of the phenotypic variation. Seven pairs of epistatic interactions were also detected, involving 11 loci distributed on chromosomes 1, 2, 3, 4, 5 and 7, respectively, which totally contributed 18.2% of the phenotypic variation. However, no significant QTL × environment (Q×E) interaction and epistasis × environment interaction effects were detected. The results showed that besides the additive QTL, epistatic interactions also formed an important genetic basis for test weight in maize.  相似文献   

17.
直播水稻茎鞘非结构碳水化合物积累与转运的遗传剖析   总被引:1,自引:0,他引:1  
为了揭示水稻(Oryza sativa)茎鞘非结构碳水化合物(nonstructural carbohydrate,NSC)积累与转运的遗传基础,在大田直播条件下,利用来源于Lemont/特青的重组自交系群体,对5个相关性状进行了QTL定位。始穗期和成熟期共检测到3个茎鞘NSC含量QTL,分别位于第1、9和12染色体上,贡献率分别为13%、7%和7%,增效等位基因均来自特青。检测到的2个NSC转运率QTL均位于第12染色体上,贡献率分别为8%和14%。检测到的结实率和千粒重QTL分别为3个和4个,3个结实率QTL的贡献率分别为9%、24%和6%,4个千粒重QTL的贡献率分别为14%、11%、12%和13%。进一步的分析表明,来自Lemont的等位基因降低成熟期茎鞘NSC含量的同时却能提高NSC转运率、结实率和千粒重,而来自特青的等位基因对NSC转运率和结实率均有增效作用,这为性状间表型相关提供了重要的遗传解释。  相似文献   

18.
玉米开花期相关性状的QTL分析   总被引:4,自引:0,他引:4  
利用玉米强优势组合(Mo17×黄早四)自交衍生的191个F_2单株构建了由SSR和AFLP标记组成的分子连锁图谱,用F2进一步自交产生的184个F_(2:3)家系调查散粉期、吐丝期和开花-吐丝间隔期(ASI)的表型值,采用基于混合线性模型的复合区间作图法和相应的作图软件QTLmapper/V2.0,在两个生长环境下定位了与散粉期、吐丝期和ASI相关的QTL数目分别为13、7和5个,检测到3对控制散粉期、17对控制吐丝期和5对控制ASI的上位性效应位点;同时发现了与环境存在显著互作的3个散粉期、3个吐丝期和2个ASI单位点标记区域以及1对散粉期、3对吐丝期和2对ASI上位性效应区域.对玉米散粉期、吐丝期和ASI遗传基础中遗传因素相对作用大小分析表明,加性效应、部分显性效应和上位性效应是玉米开花期相关性状的重要遗传基础.  相似文献   

19.
Jiang W  Jin YM  Lee J  Lee KI  Piao R  Han L  Shin JC  Jin RD  Cao T  Pan HY  Du X  Koh HJ 《Molecules and cells》2011,32(6):579-587
Low temperature is one of the major environmental stresses in rice cultivation in high-altitude and high-latitude regions. In this study, we cultivated a set of recombinant inbred lines (RIL) derived from Dasanbyeo (indica) / TR22183 (japonica) crosses in Yanji (high-latitude area), Kunming (high-altitude area), Chuncheon (cold water irrigation) and Suwon (normal) to evaluate the main effects of quantitative trait loci (QTL) and epistatic QTL (E-QTL) with regard to their interactions with environments for cold-related traits. Six QTLs for spikelet fertility (SF) were identified in three cold treatment locations. Among them, four QTLs on chromosomes 2, 7, 8, and 10 were validated by several near isogenic lines (NILs) under cold treatment in Chuncheon. A total of 57 QTLs and 76 E-QTLs for nine cold-related traits were identified as distributing on all 12 chromosomes; among them, 19 QTLs and E-QTLs showed significant interactions of QTLs and environments (QEIs). The total phenotypic variation explained by each trait ranged from 13.2 to 29.1% in QTLs, 10.6 to 29.0% in EQTLs, 2.2 to 8.8% in QEIs and 1.0% to 7.7% in E-QTL × environment interactions (E-QEIs). These results demonstrate that epistatic effects and QEIs are important properties of QTL parameters for cold tolerance at the reproductive stage. In order to develop cold tolerant varieties adaptable to wide-ranges of cold stress, a strategy facilitating marker-assisted selection (MAS) is being adopted to accumulate QTLs identified from different environments.  相似文献   

20.
Xu S  Jia Z 《Genetics》2007,175(4):1955-1963
The doubled-haploid (DH) barley population (Harrington x TR306) developed by the North American Barley Genome Mapping Project (NABGMP) for QTL mapping consisted of 145 lines and 127 markers covering a total genome length of 1270 cM. These DH lines were evaluated in approximately 25 environments for seven quantitative traits: heading, height, kernel weight, lodging, maturity, test weight, and yield. We applied an empirical Bayes method that simultaneously estimates 127 main effects for all markers and 127(127-1)/2=8001 interaction effects for all marker pairs in a single model. We found that the largest main-effect QTL (single marker) and the largest epistatic effect (single pair of markers) explained approximately 18 and 2.6% of the phenotypic variance, respectively. On average, the sum of all significant main effects and the sum of all significant epistatic effects contributed 35 and 6% of the total phenotypic variance, respectively. Epistasis seems to be negligible for all the seven traits. We also found that whether two loci interact does not depend on whether or not the loci have individual main effects. This invalidates the common practice of epistatic analysis in which epistatic effects are estimated only for pairs of loci of which both have main effects.  相似文献   

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