大豆籽粒维生素E含量的QTL分析

维生素E(VE)具有提高人体免疫力、抗癌、预防心血管疾病等保健作用,从大豆中提取的VE安全性更高。本研究采用高效液相色谱技术(HPLC)检测大豆BIEX群体(Essex×ZDD2315)维生素E的α-生育酚、γ-生育酚和δ-生育酚含量。应用QTLNetwork 2.1软件分别检测到8个和12对控制大豆维生素E及组分含量的加性和互作QTL。α-生育酚含量加性和互作QTL累计贡献值分别为8.68%(2个)和15.57%(4对),γ-生育酚含量加性和互作QTL累计贡献值分别为8.59%(2个)和11.57%(2对),δ-生育酚含量加性和互作QTL累计贡献值分别为5.44%(1个)和17.61%(3对),维生素E总含量的加性和互作QTL累计贡献值分别为11.39%(3个)和9.48%(3对)。未检测到维生素E及组分含量和环境互作的QTL。未定位到的微效QTL累计贡献值为66.16%~75.32%,说明未定位到的微效基因的变异占2/3以上。各性状的遗传构成中,未检测出的微效QTL份额最大,加性QTL和互作QTL贡献相差不大。在育种中应考虑常规方法聚合微效QTL与标记辅助方法聚合主要QTL相结合。     

Genetic structure composed of additive QTL,epistatic QTL pairs and collective unmapped minor QTL conferring oil content and fatty acid components of soybeans

The relative importance of various types of quantitative trait locus (QTL) conferring oil content and its fatty acid components in soybean seeds was assessed through testing a recombinant inbred line (RIL) population (derived from KF1 × NN1138-2) in randomized blocks experiments in 2004–2006. The contents of oil and oleic, linoleic, linolenic, palmitic and stearic acids were determined with automatic Soxhlet extraction system and gas chromatography, respectively. Based on the established genetic linkage map with 834 markers, QTLNetwork2.0 was used to detect QTL under the genetic model composed of additive, additive × additive (epistasis), additive × year and epistasis × year effects. The contributions to the phenotypic variances of additive QTL and epistatic QTL pairs were 15.7% (3 QTL) and 10.8% (2 pairs) for oil content, 10.4% (3 QTL) and 10.3% (3 pairs) for oleic acid, 11.6% (3 QTL) and 8.5% (2 pairs) for linoleic acid, 28.5% (7 QTL) and 7.6% (3 pairs) for linolenic acid, 27.0% (6 QTL) and 16.6% (7 pairs) for palmitic acid and 29.7% (5 QTL) and 4.3% (1 pair) for stearic acid, respectively. Those of additive QTL by year interaction were small and no epistatic QTL pair by year interaction was found. Among the 27 additive QTL and 36 epistatic QTL (18 pairs), three are duplicated between the two QTL types. A large difference was found between the genotypic variance among RILs and the total variance of mapped QTL, which accounted for 52.9–74.8% of the genotypic variation, much larger than those of additive QTL and epistatic QTL pairs. This part of variance was recognized as that due to a collection of unmapped minor QTL, like polygenes in biometrical genetics, and was designated as collective unmapped minor QTL. The results challenge the breeders for how to pyramid different types of QTL. In addition, the present study supports the mapping strategy of a full model scanning followed by verification with other procedures corresponding to the first results.     

Quantitative trait loci underlying soybean seed tocopherol content with main additive,epistatic and QTL × environment effects

Soybean (Glycine max [L.] Merrill) seeds are a major source of tocopherols (Toc), which could significantly improve immune system health of human and prevent or treat many serious diseases. Selection for higher Toc contents of seeds could increase nutritional value of soybean‐derived food, laying on an important breeding goal for many soybean breeders. The present objectives of the work were to evaluate various genetic effects of QTL associated with individual and total Toc content based on a RIL population (“Beifeng 9” × “Freeborn”) in six environments to improve the efficiency of molecular marker‐assisted selection (MAS) for high‐Toc breeding. The results described that eighteen, thirteen, eleven and thirteen QTL were associated with α‐Toc, γ‐Toc, δ‐Toc and total Toc content, respectively, and have additive main effects (a) and/or additive × environment interaction effects (ae) in certain environments. Among them, four QTL for α‐Toc, two QTL for γ‐Toc, one QTL for δ‐Toc and four QTL for total Toc could increase α‐Toc, γ‐Toc, δ‐Toc and total Toc content via significant a effect, respectively, which have stronger stability in different years and locations. It implied a value for MAS. Additionally, twenty‐five, fifteen, eleven and twenty epistatic pairwise QTL associated with α‐Toc, γ‐Toc, δ‐Toc and total Toc contents, respectively, were detected. The genetic information of the QTL effects obtained here would be beneficial for breeding soybean variety with high‐Toc content by MAS.     

Mapping quantitative trait loci (QTLs) underlying seed vitamin E content in soybean with main,epistatic and QTL × environment effects

Soybean (Glycine max (L.) Merr.) seed contains small amounts of tocopherol, a non‐enzymatic antioxidant known as lipid‐soluble vitamin E (VE). Dietary VE contributes to a decreased risk of chronic diseases in humans and has several beneficial effects on resistance to stress in plants, and increasing VE content is an important breeding goal for increasing the nutritional value of soybean. In this study, quantitative trait loci (QTLs) underlying VE content with main, epistatic and QTL × environment effects were identified in a population of F_5 : 6 recombinant inbred lines from a cross between ‘Hefeng 25’ (a low‐VE cultivar) and ‘OAC Bayfield’ (a high‐VE cultivar). A total of 18 QTLs were detected that showed additive main effects (a) and/or additive × environment interaction effects (ae) in different environments. Moreover, 19 epistatic pairs of QTLs were found to be associated with α‐tocopherol (α‐Toc), γ‐tocopherol (γ‐Toc), δ‐tocopherol (δ‐Toc) and total VE (TE) contents. The QTLs identified in multienvironments could provide more information about QTL by environment interactions and could be useful for the marker‐assistant selection of soybean cultivars with high seed VE contents.     

大豆叶片性状和叶绿素含量QTL间的上位性和环境互作效应

以丰产性好、抗旱力强的栽培大豆晋豆23为母本,山西农家品种半野生大豆灰布支黑豆为父本杂交衍生的447个RIL作为供试群体。将亲本及447个家系分别于2011、2012和2013年采用随机试验种植,按照标准测量叶长、叶宽和叶柄长3个性状,并于2012年8月1日和8月8日和2013年8月2日和8月9日各测量1次叶绿素含量。采用QTLNETwork 2.0混合线性模型分析方法和主基因+多基因混合遗传分离分析法,对大豆叶片性状和叶绿素含量进行遗传分析和QTL间的上位性和环境互作效应研究。结果表明,叶长受2对加性-加性×加性上位性混合主基因控制,叶宽受3对等效主基因控制,叶柄长受4对加性-加性×加性上位性主基因控制,叶绿素含量受4对加性主基因控制;检测到10个与叶长、叶宽、叶柄长和叶绿素含量相关的QTL,分别位于A1、A2、C2、H_1、L和O染色体。其中2个叶长QTL分别位于C2和L染色体,是2对加性×加性上位互作效应及环境互作效应QTL;3个叶宽加性与环境互作QTL分别位于A2、C2和O染色体;2个叶柄长QTL分别位于L和O染色体;3个叶绿素含量QTL分别位于A1、C2和H_1染色体。叶片性状和叶绿素含量的遗传机制较复杂,加性效应、加性×加性上位互作效应及环境互作效应是大豆叶片性状和叶绿素含量的重要遗传基础。建议大豆分子标记辅助育种中,一方面要考虑起主要作用的QTL,另一方面要注重上位性QTL的影响,这对于性状的遗传和稳定表达具有积极的意义。     

Impact of epistasis and QTL × environmental interaction on the oil filling rate of soybean seed at different developmental stages

The oil accumulation in the developing soybean seed has been shown to be a dynamic process with different rates and activities at different phases affected by both genotype and environment. The objective of the present study was to investigate additive, epistatic and quantitative trait loci (QTL) × environment interaction (QE) effects of the QTL controlling oil filling rate in soybean seed. A total of 143 recombinant inbred lines (RILs) derived from the cross of Charleston and Dongnong 594 were used in this study to obtain 2 years of field data (2004 and 2005). A total of 26 QTL with significantly unconditional and conditional additive (a) effect and/or additive × environment interaction (ae) effect at different filling stages were identified on 14 linkage groups. Among the QTL with significant a effects, 18 QTL showed positive effects and 6 QTL had negative effects on seed filling rate of oil content during seed development. A total of 29 epistatic pairwise QTL underlying seed filling rate were identified at different filling stages. About 28 pairs of the QTL showed additive × additive epistatic (aa) effects and 14 pairs of the QTL showed aa × environment interaction (aae) effects at different filling stages. QTL with aa and aae (additive × additive × environment) effects appeared to vary at different filling stages. Our results demonstrated that oil filling rate in soybean seed were under genetic, developmental and environmental control.     

大豆油分含量相关的QTL间的上位效应和QE互作效应

利用Charleston × 东农594重组自交系构建的SSR遗传图谱, 及混合线性模型方法对2002年到2006年连续5年的大豆油分含量进行QTL定位, 并作加性效应, 加性×加性上位互作效应及环境互作效应分析。共检测到11个控制油分含量的QTL, 分别位于第A1、A2、B1、C2、D1a、D1b、F、H和O连锁群上, 其中2个表现为遗传正效应, 9个表现为遗传负效应, 另检测到15对影响油分含量的加性×加性上位互作效应的QTL, 解释该性状总变异的17.84%。发现9个QTL与环境存在互作, 贡献率达到5.76%。     

Genetic analysis of plant height using two immortalized populations of “CRI12 × J8891” in Gossypium hirsutum L.

Plant height is an important plant architecture trait that determines the canopy structure, photosynthetic capacity and lodging resistance of upland cotton populations. To understand the genetic basis of plant height for marker-assisted breeding, quantitative trait loci (QTL) analysis was conducted based on the genetic map of recombinant inbred lines (RILs) derived from the cross “CRI12 × J8891” (Gossypium hirsutum L.). Three methods, including composite interval mapping, multiple interval mapping and multi-marker joint analysis, were used to detect QTL across multiple environments in the RILs and in the immortalized F₂ population developed through intermating between RILs. A total of 19 QTL with genetic main effects and/or genetic × environment interaction effects were identified on 15 chromosomes or linkage groups, each explaining 5.8–14.3 % of the phenotypic variation. Five digenic epistatic QTL pairs, mainly involving additive × additive and/or dominance × dominance, were detected in different environments. Seven out of eight interacting loci were main-effect QTL, suggesting that these loci act as major genes as well as modifying genes in the expression of plant height. The results demonstrate that additive effects, dominance and epistasis are all important for the genetic constitution of plant height, with additive effects playing a more important role in reducing plant height. QTL showing stability across environments that were repeatedly detected by different methods can be used in marker-assisted breeding.     

多环境下水稻DH群体剑叶长度的QTL分析

种植由籼稻品种和粳稻品种杂交衍生的DH群体,连续4年测定剑叶长度,运用基于混合模型的复合区间作图法,定位其QTL及上位性互作,估算遗传主效应和环境互作效应。结果表明,全部18个QTL都参与了上位性的形成,其中3个没有自身的遗传效应,但参与了3对上位性互作,这是传统方法不能发现的。另外,一个QTL可与多个QTL发生互作,这可能预示着存在更高阶互作。QTL与上位性互作可以具有不受环境影响而稳定表达的效应,以及与环境的互作效应。有些QTL与环境的互作效应可以在多环境下被检测到,但却不具有主效应,这种QTL可能易受环境因子的影响。QTL与环境的互作效应为随机效应,一个QTL或一对上位性与环境的互作效应总和理论上应等于零,否则会影响对遗传效应的估算,因此多环境下估算的遗传效应更可靠。     

甜玉米果皮厚度QTL的定位及上位性互作

果皮厚度是影响甜玉米口感的一个重要因素。发掘果皮厚度的基因资源、了解玉米果皮厚度的遗传机制,是指导其育种的基础。本研究以日超-1(薄果皮,56.57μm)×1021(厚果皮,100.23μm)的190个BC1F2家系为作图群体,分别采用2种遗传模型检测QTL。基于复合区间作图(CIM)共检测到3个影响果皮厚度的QTL,位于3.01、6.01、8.05区段,分别解释8.6%、16.0%和7.2%的表型变异,其中3.01和8.05处QTL以加性效应为主;基于混合线性CIM模型(MCIM)共检测到5个影响果皮厚度的QTL,其中除8.05处QTL为加性QTL外,另有2对加×加上位性互作QTL,1对是2.01和6.05处QTL之间的互作,另1对则是5.06和6.01处QTL间的互作。这2对互作QTL分别解释了6.63%和12.48%的表型变异率。本结果表明,加性效应和上位性互作效应等都在果皮厚度的形成和遗传中起重要作用。能够检测QTL上位互作的MCIM模型更适用于果皮厚度QTL定位。本研究还在其中4个QTL的区域内分别检索到胚乳中色素合成以及细胞转变的相关候选基因,这些基因的表达是否与果皮厚度的变异有关值得进一步研究。     

大豆籽粒大小与形状性状的QTL定位

大豆籽粒大小和粒形性状不仅与产量和外观品量紧密相关,还对机械化播种有着一定的影响。本研究采用大粒栽培品种冀豆12与小粒半野生地方品种黑豆(ZDD03651)杂交衍生的包含188个重组自交系的F_6:8和F_6:9群体为材料,对粒长、粒宽、粒厚、长宽比、长厚比和宽厚比的遗传结构进行分析,并分别以WinQTLCart 2.5、QTLNetwork 2.1和IciMapping 4.1 3种模型对以上性状的加性效应QTL,QE互作效应及上位性互作效应进行检测。6个性状的广义遗传率介于64.01%~79.57%,遗传力较高,且除粒厚外的其他性状受环境影响显著。共定位到加性效应QTL38个,单个QTL的贡献率介于2.21%~10.71%之间,分布在12条染色体的17个标记区间内,且12个染色体区段至少与两种性状相关。两种及以上模型同时检测到的QTL有24个,3种模型均能检测到的QTL共8个,分别为qSL-17-1、qSL-18-1、qSW-6-1、qST-2-1、qST-6-1、qSLT-2-2、qSWT-2-1和qSWT-20-1。检测到7对上位性互作QTL,分别涉及粒长、粒宽、长宽比、长厚比和宽厚比,互作效应贡献率介于0.78%~6.20%之间。QE互作效应贡献率均较低,介于0.0005%~0.3900%之间。以多种模型同时检测结果准确性较高,可为分子标记辅助育种工作提供可靠理论基础。     

Molecular mapping of soybean seed tocopherols in the cross ‘OAC Bayfield’ × ‘OAC Shire’

Soybean (Glycine max [L.] Merr.) is cultivated primarily for its protein and oil in the seed. In addition, soybean seeds contain nutraceutical compounds such as tocopherols (vitamin E), which are powerful antioxidants with health benefits. The objective of this study was to identify molecular markers linked to quantitative trait loci (QTL) that affect accumulation of soybean seed tocopherols. A recombinant inbred line (RIL) population derived from the cross ‘OAC Bayfield’ × ‘OAC Shire’ was grown in three locations over 2 years. A total of 151 SSR markers were polymorphic of which a one‐way analysis of variance identified 42 markers whereas composite interval mapping identified 26 markers linked to tocopherol QTL across 17 chromosomes. Individual QTL explained from 7% to 42% of the total phenotypic variation. Significant two‐locus epistatic interactions were identified for a total of 122 combinations in 2009 and 152 in 2010. The multiple‐locus models explained 18.4–72.2% of the total phenotypic variation. The reported QTL may be used in marker‐assisted selection (MAS) to develop high tocopherol soybean cultivars.     

Dissection of additive,epistatic and QTL × environment effects involved in oil content variations in rapeseed

In this study, we observed variation of rapeseed oil content in SG population across 11 environments. A joint mapping was conducted to detect the quantitative trait loci (QTL) involved in oil content variation. We examined additive main (a), epistatic effects (aa) and their interactions with environments (QE). Apart from a of 12 QTL (collectively to 6.74% of oil content), aa of 18 locus pairs contributed to 5.36% difference, explaining 45.3% of phenotypic variation in the population. Moreover, 28 QE interactions contributed to a change of 1.55% in oil content in each environment, accounting for 13.3% phenotypic variation. Two environmentally sensitive QTL (OilC2 and OilC8‐1) exhibited a small a (0.17) but strong ae (0.41 and 0.32 averagely). These two QTL were also frequently involved in epistatic interactions. However, two major QTL (OilA7 and OilC8‐2) showed few QE and uninvolved in epistasis. In conclusion, a and aa were the dominant contributors to oil content in rapeseed, while QE accounted for 10‐15% of variation. The results suggest OilA7 and OilC8‐2 are potential candidates for breeding utilization and gene cloning.     

A comparison of grain protein content QTLs and flour protein content QTLs across environments in cultivated wheat

The protein content of cultivated wheat (Triticum aestivum L.) is an important determinant factor of the nutritional value of the grain and the technological properties and rheological properties of flour. In order to examine the genetic basis of protein content, we searched for grain protein content quantitative trait loci (QTLs) and flour protein content QTLs in a newly developed doubled haploid (DH) line and identified the genetic correlation between grain protein content and flour protein content in the same DH population. Both the DH population and its parental lines were evaluated for grain protein content and flour protein content in three field trials. Four additive effect QTLs, two pairs of epistatic QTLs, and two QTLs × environment (QE) interaction for grain protein content were identified. The model explained 51.52% of the phenotypic variation (PVE), with epistatic effects being better explained by the higher PVE than additive effects. Four additive effect QTLs, five pairs of epistatic QTLs, and one QE were detected for flour protein content. The model explained 45.8% of the PVE. Of the 15 QTLs identified, three additive QTLs and one pair of epistatic QTLs were determined for both grain protein content and flour protein content; of these, the QTLs for protein content were considered to be more 'stable' than those detected for only grain protein content or for only flour protein content. The data reported here may be useful for manipulating the QTLs for protein content by marker-assisted selection in future wheat breeding programs.     

利用BC2F2高代回交群体定位水稻籽粒大小和形状QTL

以我国优良籼稻恢复系蜀恢527为轮回亲本, 以来自菲律宾的Milagrosa为供体亲本, 培育了样本容量为199株的BC₂F₂高代回交群体。选取85个均匀分布在12条染色体上的多态性SSR标记进行基因型分析, 同时对粒长、粒宽、长宽比和千粒重4种性状进行了表型鉴定。采用性状－标记间的单向和双向方差分析对上述性状进行了QTL定位。单向方差分析(P<0.01)共检测到了10个控制粒长、粒宽、长宽比和千粒重的QTL, 其中有3个具有多效性。由于粒长和长宽比的高度相关性, 控制长宽比的2个QTL均能在粒长QTL中检测到。位于第3染色体着丝粒区域的qgl3b是一个控制粒长、长宽比和千粒重的主效QTL, 它可以分别解释粒长、长宽比和千粒重表型变异的29.37%、26.15%和17.15%。该QTL对于粒长、长宽比和千粒重均表现较大的加性效应(来自蜀恢527的等位基因为增效)和负向超显性。位于第8染色体的qgw8位点是一个控制粒宽的主效QTL, 同时也是控制千粒重的微效QTL, 能解释粒宽表型变异的21.47%和千粒重表型变异的5.16%。该QTL对粒宽和千粒重均具有较大的加性效应(来自蜀恢527的等位基因为增效)和正向部分显性。双向方差分析(P<0.005)共检测到61对显著的上位性互作, 涉及54个QTL, 其中23个是能同时影响2~4个性状的多效位点, 且有8个位点与单向方差分析检测到的相同。控制长宽比的13对上位性互作位点中, 与控制粒长的上位性互作位点完全相同的有8对。以上结果为进一步开展水稻籽粒大小和形状有利基因的精细定位、克隆和分子设计育种奠定了基础。     

多种环境下大豆单株粒重QTL的定位与互作分析

定位大豆单株粒重QTL、分析QTL间的上位效应及QTL与环境互作效应, 有利于大豆单株粒重遗传机理的深入研究。利用147个F_2:14~F_2:18 RIL群体, 5年2点多环境下以CIM和MIM方法同时定位大豆单株粒重QTL, 检测到17个控制单株粒重的QTL, 分别位于D1a、B1、B2、C2、F、G和A1连锁群上, 贡献率为6.0%~47.9%;用2种方法同时检测到3个QTL, 即qSWPP-DIa-3、qSWPP-F-1和qSWPP-D1a-5, 贡献率为6.3%~38.3%;2年以上同时检测到4个QTL, 即qSWPP-DIa-1、qSWPP-DIa-2、qSWPP-B1-1和qSWPP-G-1, 贡献率为8.1%~47.9%;利用QTLMapper分析QE互作效应和QTL间上位效应, 7种环境下的数据联合分析得到1个QE互作QTL和4对上位效应QTL, 贡献率和加性效应都较小。在分子标记辅助育种中应该同时考虑主效QTL及各微效QTL之间的互作。     

大豆蛋白质含量相关QTL间的上位效应和QE互作效应

利用Charleston×东农594重组自交系构建的SSR遗传图谱及混合线性模型方法对2002—2006连续5年的大豆蛋白质含量进行QTL定位,并作加性效应,加性×加性上位互作效应及环境互作效应分析。共检测到10个控制蛋白质含量的QTL,分别位于第B2、C2、D1a、E和N连锁群,其中1个表现为遗传正效应,9个表现为遗传负效应,另检测到15对影响蛋白质含量的加性×加性上位互作效应的QTL,解释该性状总变异的13.75%。环境互作检测中,发现9个QTL与环境存在互作,贡献率达到4.47%。     

利用BC2F2高代回交群体定位水稻籽粒大小和形状QTL

以我国优良籼稻恢复系蜀恢527为轮回亲本, 以来自菲律宾的Milagrosa为供体亲本, 培育了样本容量为199株的BC₂F₂高代回交群体。选取85个均匀分布在12条染色体上的多态性SSR标记进行基因型分析, 同时对粒长、粒宽、长宽比和千粒重4种性状进行了表型鉴定。采用性状－标记间的单向和双向方差分析对上述性状进行了QTL定位。单向方差分析(P<0.01)共检测到了10个控制粒长、粒宽、长宽比和千粒重的QTL, 其中有3个具有多效性。由于粒长和长宽比的高度相关性, 控制长宽比的2个QTL均能在粒长QTL中检测到。位于第3染色体着丝粒区域的qgl3b是一个控制粒长、长宽比和千粒重的主效QTL, 它可以分别解释粒长、长宽比和千粒重表型变异的29.37%、26.15%和17.15%。该QTL对于粒长、长宽比和千粒重均表现较大的加性效应(来自蜀恢527的等位基因为增效)和负向超显性。位于第8染色体的qgw8位点是一个控制粒宽的主效QTL, 同时也是控制千粒重的微效QTL, 能解释粒宽表型变异的21.47%和千粒重表型变异的5.16%。该QTL对粒宽和千粒重均具有较大的加性效应(来自蜀恢527的等位基因为增效)和正向部分显性。双向方差分析(P<0.005)共检测到61对显著的上位性互作, 涉及54个QTL, 其中23个是能同时影响2~4个性状的多效位点, 且有8个位点与单向方差分析检测到的相同。控制长宽比的13对上位性互作位点中, 与控制粒长的上位性互作位点完全相同的有8对。以上结果为进一步开展水稻籽粒大小和形状有利基因的精细定位、克隆和分子设计育种奠定了基础。     

陆地棉中G6主要性状主效和上位性QTL分析

利用基于混合线性模犁的复合区间作图法对重组近交系(recombinant inbreed line,RIL)"中G6"进行QTL定位,生育期性状共定位了主效QTL位点5个,上位性QTL位点4对,纤维品质性状定位了主效QTL位点1个,上位性QTL位点6对,产量性状定位了主效QTL位点3个,上位性QTL位点5对.其中定位的果枝始节、吐絮期、上半部平均长度、衣分的主效QTL位点均距离最近标记1 cM以下,这有利于在育种实践中主效QTL跟踪检测.定位的霜前花率主效QTL位点具有较高的加性效应和遗传贡献率,应进行QTL精细定位、图位克隆,将会对早熟性育种工作有一定的推动意义.定位的马克隆值、衣分和予指总的遗传贡献率均在30%以上,对性状特征均影响显著.对主效及上位性QTL位点进行遗传效应分析,验证了前人有关数量性状遗传符合主基因与多基因混合遗传的论断,认为此模型是研究数量性状遗传的有效途经;对主效及上位性QTL位点进行A、D亚基因组定位,并对主效及上位性QTL位点在A、D亚基因组上的分布及互作方式进行了详细的分析.全文认为上位性QTL位点和主效QTL位点一样在物种遗传变异和聚合育种中起着重要作用.