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1.
High iron levels in rice soils represent a major problem for seedling establishment and crop growth, and rapid coleoptile elongation is the mechanism for the rice to cope with the induced stress. Quantitative trait loci (QTLs) analysis for coleoptile elongation rate (CER) in rice (Oryza sativa L.) was performed to study the inheritance of CER and its response to Fe nutrition. A recombinant inbred line (RIL) population of 244 lines derived from the cross zhenshan97B/miyang46 was germinated in 2004 under four Fe concentrations (0, 1.79, 7.16, and 14.32 mM). Seven QTLs with additive effects of stimulating CER were detected under the four Fe concentrations and they were localized on chromosome 1, 4, 5 and 7 with LOD ranging from 2.88 to 15.94 and their contribution to total phenotypic variance ranging from 4.17% to 15.87%, respectively. In addition, 21 QTLs with additive × additive epistasis were detected on all chromosomes but 4 and 9. The detected QTLs with additive effect mainly came from the male parent ZS97B. The detected number of QTLs with additive and epistatic effects for CER varied with Fe concentration. An additive QTL with G × Fe effect was detected between RZ460 and RZ730 markers of chromosome 1 using multi-environmental model of QTL Mapper 1.6 and considering Fe concentration as an environmental factor. The pattern of CER in the different Fe concentrations was well characterized by the genetic model of quantitative traits. It was found that some RILs had higher CER than both parents in each Fe concentration.  相似文献   

2.
Rice protein content (RPC) and rice fatcontent (RFC) are two important componentsof rice nutritional quality. In order toexamine the genetic basis of these traits,a doubled haploid (DH) population and anRFLP linkage map consisting of 232 markerloci were used to search QTLs for thetraits with the computer programQTLMapper1.0. This program is based onmixed linear models and allows simultaneousmapping of both main-effect and digenicepistastic QTLs in a DH population. RPC andRFC were evaluated based on a dry weightbasis of head rice by the Kjeldahl andSoxhlet methods respectively. A total offive main-effect QTLs for RPC wereresolved. The five QTLs collectivelyexplained 74% of the phenotypic variationwith LOD=15.2. Among these QTLs, the majorQTL qRPC-5 with the largest effectwas mapped in the interval of RG435-RG172aon chromosome 5. It accounted for 35% ofthe phenotypic variation with a LOD of16.7. At this locus the allele from theparent `Gui 630' increased RPC by 1.32%.The second QTL qRPC-7 was mapped inthe interval ZG34B-G20 on chromosome 7. Itexplained 23% of the phenotypic variancewith a LOD of 6.1. Its positive alleles,also from the parent `Gui 630', increasedRPC by 1.05%. As for the remaining threeQTLs, their additive effects wererelatively small and their positive alleleswere all inherited from the parent `02428'.Three QTLs for RFC were mapped onchromosome 1, 2 and 5 respectively. Theycollectively explained 44% of thephenotypic variation. Among these loci,QTLs qRFC-2 and qRFC-5 withlarger effects individually accounted for24% and 26% of the phenotypic variancerespectively. At QTL qRFC-2 thepositive allele came from the parent `Gui630', while at QTL qRFC-5 thepositive allele from the parent `02428'.The fact that both parents possess thepositive alleles at the QTLs for the twotraits provides an appropriate explanationfor the large transgressive segregationobserved in the DH lines. Furthermore, onlyone pair of epistatic loci explaining only5.1% of the phenotypic variance wasdetected for RPC, whereas seven pairs ofepistatic loci were resolved for RFC. Thetotal absolute effects of these RFCinteractions amounted to 0.97% which ismuch larger than that (0.42%) of the threemain-effect QTLs for the trait. Alongwith the observation that RPC showed a highheritability (78%), these resultsdemonstrate that RPC in the DH populationcould be mainly controlled by relativelyfew QTLs with large main-effects. As forRFC, epistatic interactions might be aneven more important component of thegenetic basis and the segregation of the DHlines could be largely explained by a fewmain-effect QTLs and many epistatic loci.In addition, a highly negative correlation(r = –0.45) between RPC and RFC inthe DH population was observed. Thiscorrelation could be largely explained bythe linkage of qRPC-5 and qRFC-5 with the directions of effectsopposite and the co-locations of the twoepistatic loci for RFC respectively withtwo different main-effect QTLs for RPC. Theinformation reported in the present papermay be useful for improving ricenutritional quality by means ofmarker-assisted selection.  相似文献   

3.
小麦DH群体穗下节间直径、茎壁厚及茎壁面积的QTL定位   总被引：3，自引：0，他引：3  
由小麦品种花培3号和豫麦57杂交获得168个DH株系,连续两年在山东泰安种植,利用324个SSR标记构建遗传连锁图谱,并基于混合线性模型对控制穗下节间直径、茎壁厚及茎壁面积的QTL遗传效应和环境互作效应进行分析。共检测到10个加性效应位点和6对上位效应位点,其中3个加性位点参与环境互作效应。检测到位于染色体2D、3D和5D(2个)控制穗下节间直径的4个加性QTLs,与控制茎壁厚的3个加性位点相同或相邻,表现出一因多效或紧密连锁效应。两个位于染色体2D和5D控制茎壁厚和茎壁面积QTL有较大遗传贡献率,分别为11.37%和10.98%,适用于分子标记辅助育种和聚合育种。6对上位性效应遗传贡献率较小、无环境互作效应。  相似文献   

4.
Dry matter accumulation (DMA) and photosynthetic capacity are important traits that influence biological yield and ultimate grain yield in wheat. In this study, quantitative trait loci (QTLs) analyses for DMA of stem, leaves, total plant and photosynthesis traits (Fv/Fm) at the jointing and anthesis stages were studied, using a set of 168 doubled haploid lines (DHLs) derived from the cross Huapei 3 (HP3)/Yumai 57 (YM57). QTL analyses were performed using QTL-Network 2.0 software based on the mixed linear model approach. A total of 18 additive QTLs and 12 pairs of epistatic QTLs were distributed on 16 of the 21 chromosomes. Most of the additive QTLs associated with DMA co-located in the same or adjacent chromosome intervals with QTLs for grain yield and related traits. A major locus Qculmc.sau-5D.1 (14.2%) close to the molecular marker Xwmc215 detected at the jointing stage was shared by QTLs for heading date and vernalization sensitivity, indicating tight linkages or pleiotropisms. One pair of epistatic QTLs, Qleavesc.sau-4A and Qleavesc.sau- 6B, explained 13.11% of the phenotypic variation at anthesis. All QTL × environment interactions were detected at the jointing stage, showing the importance of the jointing stage in determining the final outcome of plant development.  相似文献   

5.
Two genetic linkage maps based on doubled haploid (DH) and recombinant inbred lines (RILs) populations, derived from the same indica-japonica cross ‘Samgang × Nagdong’, were constructed to analyze the quantitative trait loci (QTLs) affecting agronomic traits in rice. The segregations of agronomic traits in RILs population showed larger variations than those in DH population. A total of 10 and 12 QTLs were identified on six chromosomes using DH population and seven chromosomes using RILs population, respectively. Three stable QTLs including pl9.1, ph1.1, and gwp11.1 were detected through different years. The percentages of phenotypic variation explained by individual QTLs ranged from 8 to 18% in the DH population and 9 to 33% in the RILs population. Twenty-three epistatic QTLs were identified in the DH population, while 21 epistatic QTLs were detected in the RILs population. Epistatic interactions played an important role in controlling the agronomic traits genetically. Four significant main-effect QTLs were involved in the digenic interactions. Significant interactions between QTLs and environments (QE) were identified in two populations. The QTLs affecting grain weight per panicle (GWP) were more sensitive to the environmental changes. The comparison and QTLs analysis between two populations across different years should help rice breeders to comprehend the genetic mechanisms of quantitative traits and improve breeding programs in marker-assisted selection (MAS).  相似文献   

6.
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.  相似文献   

7.
Falling number (FN) is an inner quality trait in wheat (Triticum aestivum L.) ultimately determining the end use of wheat kernels. In this 3-year study, 171 recombinant inbred lines derived from Chuannong17 (a 1BL/1RS tranlocation parent) × Mianyang11 were planted in the Sichuan Basin, a rainfed agricultural area in southwestern China. In this climate, we found that FN had significant differences between 1BL/1RS translocation lines and non-1BL/1RS translocation lines in two of the 3 years and the heavy fluctuation of rainfall and temperature resulted in decreasing FN in grain filling period. We used 191 simple sequence repeats markers to construct a genetic linkage map and then detected 11 additive effect FN quantitative trait loci (QTL) on chromosomes 2B, 3D, 4A, 4D, 6B and 7D, explaining 5.48–31.91% of the phenotypic variance. The FN QTL on chromosomes 4A, 4D and 6B were major or stable and detected at least in 2 years, whereas the Qfn.sicau-3D.1 in 2015 year explained the maximum phenotypic variation (about 31.91%). Furthermore, FN QTLs additive and epistatic effects as well as their interactions with environment were estimated by a mixed linear model approach. We found that the additive effect QTLs had no significant additive × environment interaction, while the paired QTLs had significant additive × additive epistatic effects however none had a significant additive × additive epistasis × environment interaction effect, excluding the paired QTLs Qfn.sicau-3B/Qfn.sicau-5B.  相似文献   

8.
Low grain cadmium (Cd) and high grain zinc (Zn) rice cultivars have become the current rice breeding objectives. However, the genetic control of Cd and Zn concentrations in brown rice remains poorly understood, especially when grown in Cd-contaminated soil. In this study, quantitative trait loci (QTLs) associated with grain Cd and Zn concentrations and Cd/Zn ratio were identified using a doubled haploid population derived from a cross between japonica JX17 and indica ZYQ8 rice cultivars. Three and two QTLs were detected for Cd and Zn concentration in brown rice, respectively. Two QTLs associated with grain Cd/Zn ratio on chromosomes 3 and 6 were initially mapped. These QTLs accounted for 10.83–41.66% of the total variance of the three traits measured. Only one common locus on chromosome 6 was found for Cd concentration and Cd/Zn ratio. The lack of co-location of the QTLs for Cd and Zn concentrations in this mapping population suggests different genetic mechanisms. In summary, our results provide insight into the genetic basis of rice grain Cd and Zn accumulation; the isolated QTLs may be useful for marker-assisted selection and identification of genes associated with Cd and Zn accumulation in rice.  相似文献   

9.
利用BC2F2高代回交群体定位水稻籽粒大小和形状QTL   总被引：1，自引：0，他引：1  
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。  相似文献   

10.
Soybean protein concentration is a key trait driver of successful soybean quality. A recombination inbred lines derived from a cross between ‘Charleston’ and ‘Dongnong594’, were planted in three environments across four years in China. Then, the genetic effects were partitioned into additive main effects, epistatic main effects and their environment interaction effects by using composite interval mapping, multiple interval mapping and composite interval mapping in a mixed linear model. Forty‐three quantitative trait loci QTLs were identified on 17 of 20 soybean chromosomes excluding Ch 7, Ch 8 and Ch 17. Two QTLs showed a good stability across multiple environments, qPRO20‐1 was detected under four environments, which explained 4.4–9.95% phenotypic variances and the allele was from ‘Charleston’ among four environments. qPRO7‐5 was detected under three environments, which explained 7.2–14.5% phenotypic variances and the allele was from ‘Dongnong 594’, three pathway genes of protein biosynthesis were detected in the interval of qPRO7‐5. The additive main‐effect QTLs contributed more phenotypic variation than the epistasis and environmental interaction. This indicated that it is feasible by marker‐assisted selection to improve soybean protein concentration.  相似文献   

11.
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.  相似文献   

12.
X. Luo  F. Tian  Y. Fu  J. Yang  C. Sun 《Plant Breeding》2009,128(6):559-567
Panicle‐related traits are important agronomic traits which directly associated with grain yield. In this study, we investigated quantitative trait loci (QTLs) associated with panicle‐related traits using a set of 265 introgression lines (ILs) of common wild rice (Oryza rufipogon Griff.) in the background of Indica high‐yielding cultivar Guichao 2 (O. sativa L.). A total of 39 QTLs associated with panicle‐related traits including panicle length (PL), primary branch number (PBN), secondary branch number (SBN), spikelet number per panicle (SPP) and spikelet density (SD), were detected in the ILs with single‐point analysis. The alleles of 20 QTLs derived from wild rice showed positive effects, and some QTLs, such as, QPl1b for PL, QPbn8 for PBN, QSd4 and QSd11b for SD and QSpp4 for SPP showed larger positive effects, providing good candidates and useful information for marker‐aided improvement of yield potential of rice. Most of the QTLs controlling SPP, SBN and SD were located in cluster or closely linked on chromosomes, and the directions of their additive effects were consistent, which explained the genetic basis of significant correlations between their phenotypic characters.  相似文献   

13.
为了探知水稻穗长的动态遗传机制,利用由穗型差异大的水稻品种Milyang 46和FJCD建立的包含130个株系的F10重组自交系,测定福建武夷山和莆田环境下穗长灌浆期的动态变化值,并进行了QTL定位及其互作研究。结果检测到35个加性QTL,16个加性×环境互作QTL,1对加加上位性效应。QTL定位分析检测到的35个加性QTL,位于1、2、4、5、7、8、9、10、11号染色体上,对表型变异贡献率0.5%~16.52%。环境互作分析检测到的16个GE互作位点,分布在水稻1、2、3、4、5、7、8、9、11号染色体上,大部分为微效QTL。武夷山环境中,还检出1对加加上位性QTL,对表型变异贡献率达到33.14%。此研究一定程度上揭示了穗长遗传机制,为水稻育种提供了依据。  相似文献   

14.
Cooking quality in rice grains is a complex trait which requires improvement. Earlier reports show varying genetic influence on these traits, except for a common agreement on waxy (Wx) and alkali degeneration (Alk) loci on chromosome 6. The present study involved 86 doubled haploid lines derived from an indica × japonica cross involving IR64 and Azucena. Grain parameters viz., raw grain length (RGL), raw grain breadth (RGB), cooked grain length (CGL), cooked grain breadth (CGB), gelatinization temperature (GT), grain shape (RGS), length elongation ratio (LER) and breadth expansion ratio (BER) were subjected to mixed model mapping of quantitative trait loci (QTL). Segregation data of 175 markers covering a distance of 2395.5 cM spanning the entire genome were used. Fifteen main effect QTLs were detected spread over the genome, except on chromosomes 4, 8 and 11. Thirty epistatic interactions significantly influencing the traits were detected. Twelve of the main effect QTLs were involved in epistatic interactions. One main effect QTL associated with LER was detected near Alk locus. QTLs located for grain length on chromosomes 9 and 10 are reported for the first time. Detection of many epistatic loci and involvement of main effect QTLs in interactions demand for judicious selection of QTLs in marker-assisted selection programmes.  相似文献   

15.
水稻孕穗期耐热性QTLs分析   总被引：15，自引：1，他引：15  
水稻籼粳亚种间杂种优势利用是提高水稻产量的重要途径。然而，异常高温或低温导致籼粳亚种间杂种育性下降是影响其优势利用的主要因素之一。本研究以USSR5（粳稻）/广解9号（籼稻）//USSR5回交群体为供试材料，构建了相应的分子连锁图谱，分别以高温处理下直接小穗育性及小穗育性热敏感指数为指标，对水稻孕穗期高温耐热性及其相对耐热性进行数量性状位点（QTLs）分析。结果表明，在第2、4和5染色体上检测到孕穗期耐热性相关的QTL各一个，对表型变异的解释率为6.4%~15.8%；在第4、8染色体上分别检测到与孕穗期相对耐热性相关的QTL，qhts-4和qhts-8，LOD值分别为3.81和2.86，对表型变异的解释率分别为16.8%和9.9%。对其进一步的上位性分析表明，有8条染色体的4对位点存在基因间互作，小穗育性耐热性除受主效QTL控制外，还受基因间互作及修饰基因的影响。  相似文献   

16.
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.  相似文献   

17.
利用BC2F2高代回交群体定位水稻籽粒大小和形状QTL   总被引：6，自引：3，他引：3  
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。  相似文献   

18.
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.  相似文献   

19.
Grain size is a main component of rice appearance quality. In this study, we performed the SSR mapping of quantitative trait loci (QTLs) controlling grain size (grain length and breadth) and shape (length/breadth ratio) using an F2 population of a cross between two Iranian cultivars, Domsephid and Gerdeh, comprising of 192 individuals. A linkage map with 88 markers was constructed, which covered 1367.9 cM of the rice genome with an average distance of 18 cM between markers. Interval mapping procedure was used to identify the QTLs controlling three grain traits, and QTLs detected were further confirmed using composite interval mapping. A total of 11 intervals carrying 18 QTLs for three traits were identifed, that included five QTLs for grain length, seven QTLs for grain breadth, and six QTLs for grain shape. A major QTL for grain length was detected on chromosome 3, that explained 19.3% of the phenotypic variation. Two major QTLs for grain breadth were mapped on chromosomes 3 and 8, which explained 34.1% and 20% of the phenotypic variation, respectively. Another two major QTLs were identified for grain shape on chromosomes 3 and 8, which accounted for 27.1% and 20.5% of the phenotypic variance, respectively. The two QTLs that were mapped for grain shape coincided with the major QTLs detected for grain length and grain breadth. Intrestingly, gs2 QTL specific to grain shape was detected on chromosome 2 that explained 15% of the phenotypic variation.  相似文献   

20.
The resistance of soybean (Glycine max L. Merr.) cultivars varies with the different races of the soybean cyst nematode (SCN), Heterodera glycines, referred to as HG types (biotypes). Resistant cultivars with durable resistance are emphasized in recent years. The aim here was to identify quantitative trait loci (QTLs) for resistance to two SCN HG types (HG type 2.5.7, race 1; and HG type 1.2.3.5.7, race 4) in resistant cultivar ‘L‐10’ and to analyse the additive and epistatic effects of the identified QTLs. A total of 140 F5‐derived F10 recombinant inbred lines (F5:10 RILs) were advanced via single‐seed‐descent from the cross between ‘L‐10’ (broadly resistant to SCN) and “Heinong 37” (SCN‐susceptible). For SCN HG type 2.5.7 and HG type 1.2.3.5.7 resistance, three and six QTLs for resistance to SCN HG type 2.5.7 and HG type 1.2.3.5.7 were identified, respectively, most of which could explain <10% of the phenotypic variation. Among these QTLs, five were identified over 2 years, while the other QTLs were detected in either 2009 or 2010. QSCN1‐2, located near the SSR marker Sat_069 of linkage group D1b (Chromosome, 2), was responsible for the largest proportion of phenotypic variation (16.01% in 2009 and 18.94% in 2010), suggested that it could effectively be used as a candidate QTL for the marker‐assisted selection (MAS) of soybean lines resistant to SCN. Additionally, for SCN HG type 2.5.7 and HG type 1.2.3.5.7 resistance, two and four QTLs showed an additive effect (a), respectively. One epistatic pair of QTLs (QSCN1‐1‐QSCN1‐3) for SCN HG type 2.5.7 resistance and eight epistatic pairs of QTLs for SCN HG type 1.2.3.5.7 resistance were found to have significant aa effects, among which one pair of QTLs (QSCN4‐4 and QSCN4‐5) contributed a large proportion of aa effects (3%). The results indicated that additive and epistatic effects could significantly affect SCN resistance. Therefore, both of a and aa effects should be considered in MAS programmes.  相似文献   

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