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1.
Quantitative trait loci (QTL) analysis was conducted in bread wheat for 14 important traits utilizing data from four different mapping populations involving different approaches of QTL analysis. Analysis for grain protein content (GPC) sug- gested that the major part of genetic variation for this trait is due to environmental interactions. In contrast, pre-harvest sprouting tolerance (PHST) was controlled mainly by main effect QTL (M-QTL) with very little genetic variation due to environmental interactions; a major QTL for PHST was detected on chromosome arm 3AL. For grain weight, one QTL each was detected on chromosome arms 1AS, 2BS and 7AS. QTL for 4 growth related traits taken together detected by different methods ranged from 37 to 40; nine QTL that were detected by single-locus as well as two-locus analyses were all M-QTL. Similarly, single-locus and two-locus QTL analyses for seven yield and yield contributing traits in two populations respectively allowed detection of 25 and 50 QTL by composite interval mapping (CIM), 16 and 25 QTL by multiple-trait composite interval mapping (MCIM) and 38 and 37 QTL by two-locus analyses. These studies should prove useful in QTL cloning and wheat improvement through marker aided selection.  相似文献   

2.
The phosphorus uptake （PU） in above-ground parts of plant, root characteristics and root exudations as well as the quantitative trait loci （QTLs） associated with these characteristics were determined for a F2：3 population derived from the cross of two contrasting maize （Zea mays L.） genotypes, 082 and Yel07. A total of 241 F2：3 families were evaluated in replicated trials under deficient phosphorus conditions in 2007 at two sites （Kaixian County and Southwest University, Chongqing, P. R. China）. The results show pleiotropy and close linkage among QTLs. Four common regions in different environments were in bnlg100- bnlg1268b （bins 1.02） for QTL of H＋, bnlg1268a-umc1290a （bins 1.09） for QTL of AP （acid phospbatase activity）, dupssrl5- P 1MT/a （bins 6.06） for QTLs of PU （phosphorus uptake） and RW （root weight）, and P IM3/d-P1M3/g （bins9.04） for QTLs of PU and AP. These QTLs are non-environment or minor QTLs x environment. By epistatic analysis, three main QTLs and eighteen QTLs x QTLs interactions were detected for the seven measured characteristics. These QTLs may affect trait expression by epistatic interaction with the other loci, and make a substantial contribution to phosphorus utilization efficiency, which should be considered when breeding maize varieties with high P efficiency. Two regions were detected in dupssrl 5- P1MT/a （bins 6.06） for QTL of RW and P1M3/d- P 1M3/g （bins 9.04） for QTL of PU and AP. They were detected in two different environments and by two methods of QTL analysis, which were useful for marker-assisted selection.  相似文献   

3.
To understand genetic patterns of the morphological and physiological traits in flag leaf of barley, a double haploid (DH) population derived from the parents Yerong and Franklin was used to determine quantitative trait loci (QTL) controlling length, width, length/width, and chlorophyll content of flag leaves. A total of 9 QTLs showing significantly additive effect were detected in 8 intervals on 5 chromosomes. The variation of individual QTL ranged from 1.9% to 20.2%. For chlorophyll content expressed as SPAD value, 4 QTLs were identified on chromosomes 2H, 3H and 6H; fur leaf length and width, 2 QTLs located on chromosomes 5H and 7H, and 2 QTLs located on chromosome 5H were detected; and for length/width, 1 QTL was detected on chromosome 7H. The identification of these QTLs associated with the properties of flag leaf is useful for barley improvement in breeding programs.  相似文献   

4.
QTLNetworkR is an R package that aims to provide a user-friendly and platform-independent tool to visualize quantitative trait loci (QTL) mapping results. The graphical functions of the QTLNetworkR are based upon lattice and grid packages, and the graphical user interface (GUI) of the QTLNetworkR is built upon RGtk2 and gWidgetsRGtk2 packages. Six functions are designed to help visualize marker interval, putative QTL, QTL-by- environment interactions, marker interval interactions, epistasis, and the predicted genetic architecture of complex traits. It is especially helpful in profiling results for multiple traits at multiple environments. The current version of QTLNetworkR is able to accept QTL mapping results from QTLNetwork, and it is ready for possible extensions to import results from some other QTL mapping software packages. In addition, we presented a QTL mapping result in rice (Oryza sativa) as an example to describe the features of QTLNetworkR.  相似文献   

5.
To understand genetic patterns of the morphological and physiological traits in flag leaf of barley, a double haploid (DH) population derived from the parents Yerong and Franklin was used to determine quantitative trait loci (QTL) controlling length, width, length/width, and chlorophyll content of flag leaves. A total of 9 QTLs showing significantly additive effect were detected in 8 intervals on 5 chromosomes. The variation of individual QTL ranged from 1.9% to 20.2%. For chlorophyll content expressed as SPAD value, 4 QTLs were identified on chromosomes 2H, 3H and 6H; for leaf length and width, 2 QTLs located on chromosomes 5H and 7H, and 2 QTLs located on chromosome 5H were detected; and for length/width, 1 QTL was detected on chromosome 7H. The identification of these QTLs associated with the properties of flag leaf is useful for barley improvement in breeding programs. Project supported by the National Natural Science Foundation of China (No. 30630047) and the Project on Absorption of Intellects by Institutions of Higher Education for Academic Disciplinary Innovations (the 111 Project) (No. B06014), China  相似文献   

6.
A genetic linkage map comprised of 131 loci was constructed with an F2 population derived from an inter-subspecific cross between Brassica 'qisihai'. The genetic map included 93 RAPD loci, 36 AFLP loci and 2 morphological loci organized into 10 main linkage groups (LGs) and 2 small groups, covering 1810.9cM with average distance between adjacent markers being approximately 13.8cM. The map is suitable for identification of molecular markers linked to important agronomic traits, QTL analysis, and even for marker-assisted selection in breeding programs of Chinese cabbage and turnip.  相似文献   

7.
QTLNetworkR is an R package that aims to provide a user-friendly and platform-independent tool to visualize quantitative trait loci (QTL) mapping results. The graphical functions of the QTLNetworkR are based upon lattice and grid packages, and the graphical user interface (GUI) of the QTLNetworkR is built upon RGtk2 and gWidgetsRGtk2 packages. Six functions are designed to help visualize marker interval, putative QTL, QTL-by-environment interactions, marker interval interactions, epistasis, and the predicted genetic architecture of complex traits. It is especially helpful in profiling results for multiple traits at multiple environments. The current version of QTLNetworkR is able to accept QTL mapping results from QTLNetwork, and it is ready for possible extensions to import results from some other QTL mapping software packages. In addition, we presented a QTL mapping result in rice (Oryza sativa) as an example to describe the features of QTLNetworkR.  相似文献   

8.
An approach for generating interactive 3D graphical visualization of the genetic architectures of complex traits in multiple environments is described. 3D graphical visualization is utilized for making improvements on traditional plots in quan- titative trait locus (QTL) mapping analysis. Interactive 3D graphical visualization for abstract expression of QTL, epistasis and their environmental interactions for experimental populations was developed in framework of user-friendly software QTLNetwork (http://ibi.zju.edu.cn/software/qtlnetwork). Novel definition of graphical meta system and computation of virtual coordinates are used to achieve explicit but meaningful visualization. Interactive 3D graphical visualization for QTL analysis provides geneticists and breeders a powerful and easy-to-use tool to analyze and publish their research results.  相似文献   

9.
巴克夏猪的选育   总被引：1，自引：0，他引：1  
近几年来,通过对巴克夏猪杂交育种,选育的巴克夏猪肉质鲜嫩、肌间脂肪分布均匀而备受消费者青睐,产品一直供不应求,具有良好的发展前景和经济效益。因此对该品种进行有步骤的良种选育,稳定其遗传性状,扩大养殖规模迫在眉睫。  相似文献   

10.
INTRODUCTIONKilo-grainweight,characteristicallyacom-plextrait,isanimportantcomponentofyieldinrice.QTLmappingforkilo-grainweightofricewascon-ductedusingpopulationsofF2(Linetal.,1996),doubledhaploidlines(Luetal.,1997),recombi-nantinbredlines(Xiaoetal.,1996),backcrosstestcross(Xiaoetal.,1995;Lietal.,1997)andratoonedF2(Lietal.,2000).Consideringthesen-sitivityofkilo-grainweighttoenvironments,Luetal.(1997)andZhuangetal.(1997)comparedthedifferentialdetectionofQTLacrossenvironmentstodetermin…  相似文献   

11.
The expansion of higher education (HE) in the UK has disproportionately benefited young people from relatively rich families: the gap between rich and poor in terms of participation in HE having widened since the 1970s. We explore a neglected possible cause of this class difference: that the labour market fails to provide sufficient incentives for potential entrants from less advantaged backgrounds to enter HE. Most studies of the rewards from participating in HE in the UK suggest that the rates of returns are sufficiently high to provide clear economic incentives to participate. However, until recently, most studies generated estimates of the average rate of return to graduation, which could overestimate returns to marginal entrants, particularly those from disadvantaged backgrounds. In this review we examine the methodological problems faced by more targeted studies of the rates of return to graduation and review their key findings concerning the economic returns to non‐traditional entrants.  相似文献   

12.
Immortalized F2 population of rice (Oryza sativa L.) was developed by randomly mating F1 among recombinant inbred (RI) lines derived from (Zhenshan 97B ( Minghui 63), which allowed replications within and across environments. QTL (quantitative trait loci) mapping analysis on kilo-grain weight of immortalized F2 population was performed by using newly developed software for QTL mapping, QTLMapper 2.0. Eleven distinctly digenic epistatic loci included a total of 15 QTL were located on eight chromosomes. QTL main effects of additive, dominance, and additive ( additive, additive ( dominance, and dominance ( dominance interactions were estimated. Interaction effects between QTL main effects and environments (QE) were predicted. Less than 40% of single effects, most of which were additive effects, for identified QTL were significant at 5% level. The directional difference for QTL main effects suggested that these QTL were distributed in parents in the repulsion phase. This should make it feasible to improve kilo-grain weight of both parents by selecting appropriate new recombinants. Only few of the QE interaction effects were significant. Application prospect for QTL mapping achievements in genetic breeding was discussed.  相似文献   

13.
High malting quality of barley (Hordeum vulgate L.) relies on many traits, such as β-amylase and limit dextrinase activities and β-glucan and protein fraction contents. In this study, interval mapping was utilized to detect quantitative trait loci (QTLs) affecting these malting quality parameters using a doubled haploid (DH) population from a cross of CM72 (six-rowed) by Gairdner (two-rowed) barley cultivars. A total of nine QTLs for eight traits were mapped to chromosomes 3H, 4H, 5H, and 7H. Five of the nine QTLs mapped to chromosome 3H, indicating a possible role of loci on chromosome 3H on malting quality. The phenotypic variation accounted by individual QTL ranged from 8.08% to 30.25%. The loci of QTLs for β-glucan and limit dex-trinase were identified on chromosomes 4H and 5H, respectively. QTL for hordeins was coincident with the region of silica eluate (SE) protein on 3HS, while QTLs for albumins, globulins, and total protein exhibited overlapping. One locus on chromosome 3H was found to be related to β-amylase, and two loci on chromosomes 5H and 7H were found to be associated with glutelins. The identification of these novel QTLs controlling malting quality may be useful for marker-assisted selection in improving barley malting quality.  相似文献   

14.
Rice straw is always regarded as a by-product of rice production, but it could be a significant energy source for ruminant animals. Knowledge of the genetic variation and genetic architecture of cell wall traits will facilitate rice breeders by improving relevant traits through selective breeding and genetic engineering. The common wild rice, Oryza rufipogon Griff., which is considered to be the progenitor of Oryza sativa, has been widely utilized for the identification of genes of agronomic importance for rice genetic improvement. In the present study, the mapping of quantitative trait loci (QTLs) for acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), and ADL/NDF ratio was carried out in two environments using a backcrossed inbred line (BIL) population derived from a cross between the recurrent parent Xieqingzao B (XB) and an accession of Dongxiang wild rice (DWR). The results indicated that all four traits tested were continuously distributed among the BILs, but many BILs showed transgressive segregation. A total of 16 QTLs were identified for the four traits, but no QTLs were in common in two environments, suggesting that environment has dramatic effects on fiber and lignin syntheses. Compared to the QTL positions for grain yield-related traits, there were no unfavorable correlations between grain yield components and cell wall traits in this population. The QTLs identified in this study are useful for the development of dual-purpose rice varieties that are high in grain yield and are also high in straw quality.  相似文献   

15.
A method was proposed for the detection of outliers and influential observations in the framework of a mixed linear model, prior to the quantitative trait locus (QTL) mapping analysis. We investigated the impact of outliers on QTL mapping for complex traits in a mouse BXD population, and observed that the dropping of outliers could provide the evidence of additional QTL and epistatic loci affecting the 1 stBrain-OB and the 2ndBrain-OB in a cross of the abovementioned population. The results could also reveal a remarkable increase in estimating heritabilities of QTL in the absence of outliers. In addition, simulations were conducted to investigate the detection powers and false discovery rates (FDRs) of QTLs in the presence and absence of outliers. The results suggested that the presence of a small proportion of outliers could increase the FDR and hence decrease the detection power of QTLs. A drastic increase could be obtained in the estimates of standard errors for position, additive and additivex environment interaction effects of QTLs in the presence of outliers.  相似文献   

16.
Immortalized F2 population of rice (Oryza sativa L.) was developed by randomly mating F1 among recombinant inbred (RI) lines derived from (Zhenshan 97B × Minghui 63), which allowed replications within and across environments. OTL (quantitative trait loci) mapping analysis on kilo-grain weight of immortalized F2 population was performed by using newly developed software for QTL mapping, QTLMapper 2.0. Eleven distinctly digenic epistatic loci included a total of 15 QTL were located on eight chromosome. QTL main effects of additive, domainance, and additive × additive, additive × domainance, and dominance × dominance interactions were estimated. Interaction effects between QTL main effects and environments (QE) were predicted. Less than 40% of single effects, most of which were additive effects, for identified QTL were significant at 5% level. The directional difference for QTL main effects suggested that these QTL were distributed in parents in the repulsion phase. This should make it feasible to improve kilo-grain weight of both parents by selecting apprents in the repulsion phase. This should make it feasible to improve kilo-grain weight of both parents by selecting appropriate new recombinants. Only few of theQE interaction effects were significant. Application prospect for QTL mapping achievements in genetic breeding was discussed. Project (No. 39893354) supported by the National Natural Science Foundation of China  相似文献   

17.
This study estimates the private average rate of return (ARR) and internal rate of return (IRR) to education in rural Bangladesh. Using data from the Bangladesh Integrated Household Survey (BIHS) 2015, we estimate average returns using the Mincerian method and IRR using the full method, accounting for both the direct and indirect costs of schooling. To account for endogeneity and selection bias, we use parental education as an instrumental variable and apply the Heckman correction method. We find an average return of 18 %, an IRR of 12 % for tertiary education, 4.86 % for secondary, and 5.24 % for primary. In the agricultural sector specifically, however, returns to tertiary education are more in line with primary and secondary education.  相似文献   

18.
This paper examines the earnings returns to learning that takes place following the conventional ‘school-to-work’ stage of the life-course. We operationalise such ‘lifelong learning’ as the attainment of certified qualifications in adulthood, following the completion of the first period of continuous full-time education. Using data from the British Household Panel Survey (BHPS) for the period 1991–2006, our approach and findings represent an important addition to the existing evidence base. By using annual data, we are able to employ the fixed effects estimator, which eliminates the problem of time-invariant unobserved heterogeneity. Our dynamic specification uses a lag structure to consider how earnings returns evolve in the medium and longer run, whilst also controlling for wage trends which were evident prior to qualification attainment. Our results show a medium-run return for women of 10% on hourly wages. For men, initial suggestions of a similar positive return are eliminated once pre-qualification trends are taken into account. This suggests that adult learning has a causal effect on women's subsequent earnings but, for men, any apparent gain is due to selection.  相似文献   

19.
A genetic linkage map comprised of 131 loci was constructed with an F2 population derived from an inter-subspecific cross betweenBrassica campestris L. ssp.chinensis cv. ‘aijiaohuang’ and ssp.rapifera cv. ‘qisihai’. The genetic map included 93 RAPD loci, 36 AFLP loci and 2 morphological loci organized into 10 main linkage groups (LGs) and 2 small groups, covering 1810.9cM with average distance between adjacent markers being approximately 13.8cM. The map is suitable for identification of molecular markers linked to important agronomic traits, QTL analysis, and even for marker-assisted selection in breeding programs of Chinese cabbage and turnip. Project (No. 39870509) supported by the National Natural Science Foundation of China  相似文献   

20.
Quantitative trait loci (QTL) and their additive, dominance and epistatic effects play a critical role in complex trait variation. It is often infeasible to detect multiple interacting QTL due to main effects often being confounded by interaction effects. Positioning interacting QTL within a small region is even more difficult. We present a variance component approach nested in an empirical Bayesian method, which simultaneously takes into account additive, dominance and epistatic effects due to multiple interacting QTL. The covariance structure used in the variance component approach is based on combined linkage disequilibrium and linkage (LDL) information. In a simulation study where there are complex epistatic interactions between QTL, it is possible to simultaneously fine map interacting QTL using the proposed approach. The present method combined with LDL information can efficiently detect QTL and their dominance and epistatic effects, making it possible to simultaneously fine map main and epistatic QTL.  相似文献   

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