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1.
QTL mapping of yield and fiber traits based on a four-way cross population in <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L. 总被引:2,自引:0,他引:2
Qin H Guo W Zhang YM Zhang T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,117(6):883-894
Four-way cross (4WC) involving four different inbred lines frequently appears in the cotton breeding programs. However, linkage
analysis and quantitative trait loci (QTL) mapping with molecular markers in cotton has largely been applied to populations
derived from a cross between two inbred lines, and few results of QTL dissection were conducted in a 4WC population. In this
study, an attempt was made to construct a linkage map and identify QTL for yield and fiber quality traits in 4WC derived from
four different inbred lines in Gossypium hirsutum L. A linkage map was constructed with 285 SSR loci and one morphological locus, covering 2113.3 cM, approximately 42% of
the total recombination length of the cotton genome. A total of 31 QTL with 5.1–25.8% of the total phenotypic variance explained
were detected. Twenty-four common QTL across environments showed high stability, and six QTL were environment-specific. Several
genomic segments affecting multiple traits were identified. The advantage of QTL mapping using a 4WC were discussed. This
study presents the first example of QTL mapping using a 4WC population in upland cotton. The results presented here will enhance
the understanding of the genetic basis of yield and fiber quality traits and enable further marker-assisted selection in cultivar
populations in upland cotton. 相似文献
2.
Blair MW Iriarte G Beebe S 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(6):1149-1163
Advanced backcross QTL analysis was used to identify quantitative trait loci (QTL) for agronomic performance in a population
of BC2F3:5 introgression lines created from the cross of a Colombian large red-seeded commercial cultivar, ICA Cerinza, and a wild common
bean accession, G24404. A total of 157 lines were evaluated for phenological traits, plant architecture, seed weight, yield
and yield components in replicated trials in three environments in Colombia and genotyped with microsatellite, SCAR, and phaseolin
markers that were used to create a genetic map that covered all 11 linkage groups of the common bean genome with markers spaced
at an average distance of every 10.4 cM. Segregation distortion was most significant in regions orthologous for a seed coat
color locus (R-C) on linkage group b08 and two domestication syndrome genes, one on linkage group b01 at the determinacy (fin) locus and the other on linkage group b02 at the seed-shattering (st) locus. Composite interval mapping analysis identified a total of 41 significant QTL for the eight traits measured of which
five for seed weight, two for days to flowering, and one for yield were consistent across two or more environments. QTL were
located on every linkage group with b06 showing the greatest number of independent loci. A total of 13 QTL for plant height,
yield and yield components along with a single QTL for seed size showed positive alleles from the wild parent while the remaining
QTL showed positive alleles from the cultivated parent. Some QTL co-localized with regions that had previously been described
to be important for these traits. Compensation was observed between greater pod and seed production and smaller seed size
and may have resulted from QTL for these traits being linked or pleiotropic. Although wild beans have been used before to
transfer biotic stress resistance traits, this study is the first to attempt to simultaneously obtain a higher yield potential
from wild beans and to analyze this trait with single-copy markers. The wild accession was notable for being from a unique
center of diversity and for contributing positive alleles for yield and other traits to the introgression lines showing the
potential that advanced backcrossing has in common bean improvement. 相似文献
3.
Renzhong Liu Baohua Wang Wangzhen Guo Yongsheng Qin Liguo Wang Yuanming Zhang Tianzhen Zhang 《Molecular breeding : new strategies in plant improvement》2012,29(2):297-311
Quantitative trait loci (QTL) mapping provides a powerful tool for unraveling the genetic basis of yield and yield components
as well as heterosis in upland cotton. In this research, a molecular linkage map of Xiangzamian 2 (Gossypium hirsutum L.)-derived recombinant inbred lines (RILs) was reconstructed based on increased expressed sequence tag–simple sequence repeat
markers. Both the RILs and immortalized F2s (IF2) developed through intermating between RILs were grown under multiple environments.
Yield and yield components including seed-cotton yield, lint yield, bolls/plant, boll weight, lint percentage, seed index,
lint index and fruit branch number were measured and their QTL were repeatedly identified across environments by the composite
interval mapping (CIM) method. From a total of 111 non-redundant QTL, 23 were detected in both two populations. In the meantime,
multi-marker joint analyses showed that 16 of these QTL had significant environmental interaction. QTL for correlated traits
tended to be collocated and most of the QTL for seed-cotton yield and lint yield were associated with QTL for at least one
yield component, consistent with the results observed in correlation analyses. For many QTL with significant additive effects,
positive alleles from CRI12, the inferior parent with lower yield performance, were associated with trait improvement. Trait
performance of IF2s and the large number of QTL with positive dominant effects implied that dominance plays an important role
in the genetic basis of heterosis in Xiangzamian 2 and that non-additive inheritance is also an important genetic mode for
lint percentage in the population. These QTL can provide the bases for marker-assisted breeding programs of upland cotton. 相似文献
4.
Chen W Zhang Y Liu X Chen B Tu J Tingdong F 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(6):849-858
The inheritance of yield-related traits in rapeseed (Brassica napus) is poorly understood, and the investigations on mapping of quantitative trait loci (QTL) for such traits are only few. QTL
related to six traits were mapped which include plant height (PH), height of lowest primary effective branch (HPB), length
of main inflorescence (LMI), silique length (SL), number of primary branches (FB) and silique density (SD). A set of 258 doubled
haploid (DH) lines derivatives of a cross between a canola variety Quantum and a resynthesized B. napus line No.2127-17, and a fixed immortalized F2 (designated as IF2) population generated by randomly permutated intermating of these DHs were investigated. A genetic linkage map was constructed
using 208 SSR and 189 SRAP markers for the DH population. Phenotypic data were collected from three environments for the two
populations. Using composite interval mapping analyses, 30 and 22 significant QTL were repeatedly detected across environments
for the six traits in the DH and IF2 populations, respectively. Twenty-nine QTL were common between the two populations. The directions of parental contribution
for all common QTL were the same, showing a great potential for marker-assisted selection in improving these traits. Some
chromosomal regions harbor QTL for multiple traits, which were consistent with significant phenotypic correlations observed
among traits. The results provided a better understanding of the genetic factors controlling yield-related traits in rapeseed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
Andru S Pan YB Thongthawee S Burner DM Kimbeng CA 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(1):77-93
Tef is a cereal crop of cultural and economic importance in Ethiopia. It is grown primarily for its grain though it is also
an important source of fodder. Tef suffers from lodging that reduces both grain yield and quality. As a first step toward
executing a marker-assisted breeding program for lodging resistance and grain yield improvement, a linkage map was constructed
using 151 F9 recombinant inbred lines obtained by single-seed-descent from a cross between Eragrostis tef and its wild relative Eragrostis pilosa. The map was primarily based on microsatellite (SSR) markers that were developed from SSR-enriched genomic libraries. The
map consisted of 30 linkage groups and spanned a total length of 1,277.4 cM (78.7% of the genome) with an average distance
of 5.7 cM between markers. This is the most saturated map for tef to date, and for the first time, all of the markers are
PCR-based. Using agronomic data from 11 environments and marker data, it was possible to map quantitative trait loci (QTL)
controlling lodging, grain yield and 15 other related traits. The positive effects of the QTL identified from the wild parent
were mainly for earliness, reduced culm length and lodging resistance. In this population, it is now possible to combine lodging
resistance and grain yield using a marker-assisted selection program targeting the QTL identified for both traits. The newly
developed SSR markers will play a key role in germplasm organization, fingerprinting and monitoring the success of the hybridization
process in intra-specific crosses lacking distinctive morphological markers. 相似文献
6.
Touming Liu Shouwei Tang Siyuan Zhu Qingming Tang 《Molecular breeding : new strategies in plant improvement》2014,34(3):883-892
Ramie fiber extracted from stem bast is one of the most important natural fibers. The fiber yield of ramie is a valuable trait and is decided by several components, including stem number per plant (SN), the fiber yield per stem (FYPS), stem length (SL), stem diameter (SD), and bark thickness (BT). All of these fiber yield-related traits are inherited in a quantitative manner. The genetic basis for these traits is still uncharacterized, which has hindered the improvement of yield traits through selective ramie breeding. In this study, an F2 population derived from two ramie varieties, Zhongzhu 1 and Qingyezhuma, with striking differences in fiber yield-related traits, was used for cutting propagation and to develop an F2 agamous line (FAL) population. A genetic linkage map with 132 DNA loci spanning 2,265.1 cM was first constructed. The analysis of quantitative trait locus (QTL) for fiber yield-related traits was performed in ramie for the first time. Finally, a total of 6, 9, 5, 7, and 6 QTLs for FYPS, SL, SN, SD, and BT, respectively, were identified in the FAL population in two environments. Among these 33 QTLs, 9 QTLs were detected in both environments and 24 QTLs exhibited overdominance. The overdominance of these QTLs possibly contributed to the heterosis of these yield-related traits in ramie. Moreover, there were 7 QTL clusters identified. The identification of the QTLs for fiber yield-related traits will be helpful for improving the fiber yield in ramie breeding programs. 相似文献
7.
Ruixiang Liu Haitao Jia Xiaoliang Cao Jun Huang Feng Li Yongsheng Tao Fazhan Qiu Yonglian Zheng Zuxin Zhang 《PloS one》2012,7(11)
The yield of maize grain is a highly complex quantitative trait that is controlled by multiple quantitative trait loci (QTLs) with small effects, and is frequently influenced by multiple genetic and environmental factors. Thus, it is challenging to clone a QTL for grain yield in the maize genome. Previously, we identified a major QTL, qKNPR6, for kernel number per row (KNPR) across multiple environments, and developed two nearly isogenic lines, SL57-6 and Ye478, which differ only in the allelic constitution at the short segment harboring the QTL. Recently, qKNPR6 was re-evaluated in segregating populations derived from SL57-6×Ye478, and was narrowed down to a 2.8 cM interval, which explained 56.3% of the phenotypic variance of KNPR in 201 F2∶3 families. The QTL simultaneously affected ear length, kernel weight and grain yield. Furthermore, a large F2 population with more than 12,800 plants, 191 recombinant chromosomes and 10 overlapping recombinant lines placed qKNPR6 into a 0.91 cM interval corresponding to 198Kb of the B73 reference genome. In this region, six genes with expressed sequence tag (EST) evidence were annotated. The expression pattern and DNA diversity of the six genes were assayed in Ye478 and SL57-6. The possible candidate gene and the pathway involved in inflorescence development were discussed. 相似文献
8.
9.
Yaxi Liu Yu Lin Shang Gao Zhanyi Li Jian Ma Mei Deng Guoyue Chen Yuming Wei Youliang Zheng 《The Plant journal : for cell and molecular biology》2017,91(5):861-873
Uncovering the genetic basis of agronomic traits in wheat landraces is important for ensuring global food security via the development of improved varieties. Here, 723 wheat landraces from 10 Chinese agro‐ecological zones were evaluated for 23 agronomic traits in six environments. All accessions could be clustered into five subgroups based on phenotypic data via discriminant function analysis, which was highly consistent with genotypic classification. A genome‐wide association study was conducted for these traits using 52 303 DArT‐seq markers to identify marker‐trait associations and candidate genes. Using both the general linear model and the mixed linear model, 149 significant markers were identified for 21 agronomic traits based on best linear unbiased prediction values. Considering the linkage disequilibrium decay distance in this study, significant markers within 10 cM were combined as a quantitative trait locus (QTL), with a total of 29 QTL identified for 15 traits. Of these, five QTL for heading date, flag leaf width, peduncle length, and thousand kernel weight had been reported previously. Twenty‐five candidate genes associated with significant markers were identified. These included the known vernalization genes VRN‐B1 and vrn‐B3 and the photoperiod response genes Ppd and PRR. Overall, this study should be helpful in elucidating the underlying genetic mechanisms of complex agronomic traits and performing marker‐assisted selection in wheat. 相似文献
10.
A. Blanco G. Mangini A. Giancaspro S. Giove P. Colasuonno R. Simeone A. Signorile P. De Vita A. M. Mastrangelo L. Cattivelli A. Gadaleta 《Molecular breeding : new strategies in plant improvement》2012,30(1):79-92
Grain protein content (GPC) in durum wheat (Triticum turgidum var. durum) is negatively correlated with grain yield. To evaluate possible genetic interrelationships between GPC and grain yield per spike, thousand-kernel weight and kernel number per spike, quantitative trait loci (QTL) for GPC were mapped using GPC-adjusted data in a covariance analysis on yield components. Phenotypic data were evaluated in a segregating population of 120 recombinant inbred lines derived from crossing the elite cultivars Svevo and Ciccio. The material was tested at five environments in southern Italy. QTL were determined by composite interval mapping based on the Svevo?×?Ciccio linkage map described in Gadaleta et al. (2009) and integrated with DArT markers. The close relationship between GPC and yield components was reflected in the negative correlation between the traits and in the reduction of variance when GPC values were adjusted to yield components. Ten independent genomic regions involved in the expression of GPC were detected, six of which were associated with QTL for one or more grain yield components. QTL alleles with increased GPC effects were associated with QTL alleles with decreased effects on one or more yield component traits, or vice versa (i.e. the allelic effects were in opposite direction). Four QTL for GPC showed always significant effects, and these QTL should represent genes that influence GPC independently from variation in the yield components. Such genes are of special interest in wheat breeding since they would allow an increase in GPC without a concomitant decrease in grain yield. 相似文献
11.
Ramchiary N Padmaja KL Sharma S Gupta V Sodhi YS Mukhopadhyay A Arumugam N Pental D Pradhan AK 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(6):807-817
Quantitative trait loci (QTL) analysis of yield influencing traits was carried out in Brassica juncea (AABB) using a doubled haploid (DH) mapping population of 123 lines derived from a cross between Varuna (a line representing
the Indian gene pool) and Heera (representing the east European gene pool) to identify potentially useful alleles from both
the parents. The existing AFLP based map of B. juncea was further saturated with RFLP and SSR markers which led to the identification of the linkage groups belonging to the A
(B. rapa) and B (B. nigra) genome components of B. juncea. For QTL dissection, the DH lines were evaluated at three different environments and phenotyped for 12 quantitative traits.
A total of 65 QTL spread over 13 linkage groups (LG) were identified from the three environments. QTL analysis showed that
the A genome has contributed more than the B genome to productivity (68% of the total QTL detected) suggesting a more prominent
role of the A genome towards domestication of this crop. The east European line, Heera, carried favorable alleles for 42%
of the detected QTL and the remaining 58% were in the Indian gene pool line, Varuna. We observed clustering of major QTL in
a few linkage groups, particularly in J7 and J10 of the A genome, with QTL of different traits having agronomically antagonistic
allelic effects co-mapping to the same genetic interval. QTL analysis also identified some well-separated QTL which could
be readily transferred between the two pools. Based on the QTL analysis, we propose that improvement in yield could be achieved
more readily by heterosis breeding rather than by pure line breeding.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Inheritance of long staple fiber quality traits of Gossypium barbadense in G. hirsutum background using CSILs 总被引:3,自引:0,他引:3
Wang P Zhu Y Song X Cao Z Ding Y Liu B Zhu X Wang S Guo W Zhang T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(8):1415-1428
Gossypium hirsutum is a high yield cotton species that exhibits only moderate performance in fiber qualities. A promising but challenging approach
to improving its phenotypes is interspecific introgression, the transfer of valuable traits or genes from the germplasm of
another species such as G. barbadense, an important cultivated extra long staple cotton species. One set of chromosome segment introgression lines (CSILs) was developed,
where TM-1, the genetic standard in G. hirsutum, was used as the recipient parent and the long staple cotton G. barbadense Hai7124 was used as the donor parent by molecular marker-assisted selection (MAS) in BC5S1–4 and BC4S1–3 generations. After four rounds of MAS, the CSIL population was comprised of 174 lines containing 298 introgressed segments,
of which 86 (49.4%) lines had single introgressed segments. The total introgressed segment length covered 2,948.7 cM with
an average length of 16.7 cM and represented 83.3% of tetraploid cotton genome. The CSILs were highly varied in major fiber
qualities. By integrated analysis of data collected in four environments, a total of 43 additive quantitative trait loci (QTL)
and six epistatic QTL associated with fiber qualities were detected by QTL IciMapping 3.0 and multi-QTL joint analysis. Six
stable QTL were detected in various environments. The CSILs developed and the analyses presented here will enhance the understanding
of the genetics of fiber qualities in long staple G. barbadense and facilitate further molecular breeding to improve fiber quality in Upland cotton. 相似文献
13.
Li YL Niu SZ Dong YB Cui DQ Wang YZ Liu YY Wei MG 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(1):129-140
Normal maize germplasm could be used to improve the grain yield of popcorn inbreds. Our first objective was to locate genetic
factors associated with trait variation and make first assessment on the efficiency of advanced backcross quantitative trait
locus (AB-QTL) analysis for the identification and transfer of favorable QTL alleles for grain yield components from the dent
corn inbred. A second objective was to compare the detection of QTL in the BC2F2 population with results using F2:3 lines of the same parents. Two hundred and twenty selected BC2F2 families developed from a cross between Dan232 and an elite popcorn inbred N04 were evaluated for six grain yield components
under two environments, and genotyped by means of 170 SSR markers. Using composite interval mapping (CIM), a total of 19 significant
QTL were detected. Eighteen QTL had favorable alleles contributed by the dent corn parent Dan232. Sixteen of these favorable
QTL alleles were not in the same or near marker intervals with QTL for popping characteristics. Six QTL were also detected
in the F2:3 population. Improved N04 could be developed from 210 and 208 families with higher grain weight per plant and/or 100-grain
weight, respectively, and 35 families with the same or higher popping expansion volume than N04. In addition, near isogenic
lines containing detected QTL (QTL-NILs) for grain weight per plant and/or 100-grain weight could be obtained from 12 families.
Our study demonstrated that the AB-QTL method can be applied to identify and manipulate favorable QTL alleles from normal
corn inbreds and combine QTL detection and popcorn breeding efficiently. 相似文献
14.
QTL Mapping for Frond Length and Width in Laminaria japonica Aresch (Laminarales, Phaeophyta) Using AFLP and SSR Markers 总被引:1,自引:0,他引:1
Fuli Liu Zhanru Shao Haining Zhang Jidong Liu Xiuliang Wang Delin Duan 《Marine biotechnology (New York, N.Y.)》2010,12(4):386-394
In Laminaria japonica Aresch breeding practice, two quantitative traits, frond length (FL) and frond width (FW), are the most important phenotypic
selection index. In order to increase the breeding efficiency by integrating phenotypic selection and marker-assisted selection,
the first set of QTL controlling the two traits were determined in F2 family using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Two prominent L. japonicas inbred lines, one with “broad and thin blade” characteristics and another with “long and narrow blade” characteristics, were
applied in the hybridization to yield the F2 mapping population with 92 individuals. A total of 287 AFLP markers and 11 SSR markers were used to construct a L. japonica genetic map. The yielded map was consisted of 28 linkage groups (LG) named LG1 to LG28, spanning 1,811.1 cM with an average
interval of 6.7 cM and covering the 82.8% of the estimated genome 2,186.7 cM. While three genome-wide significant QTL were
detected on LG1 (two QTL) and LG4 for “FL,” explaining in total 42.36% of the phenotypic variance, two QTL were identified
on LG3 and LG5 for the trait “FW,” accounting for the total of 36.39% of the phenotypic variance. The gene action of these
QTL was additive and partially dominant. The yielded linkage map and the detected QTL can provide a tool for further genetic
analysis of two traits and be potential for maker-assisted selection in L. japonica breeding. 相似文献
15.
K. Satish G. Srinivas R. Madhusudhana P. G. Padmaja R. Nagaraja Reddy S. Murali Mohan N. Seetharama 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(8):1425-1439
The shoot fly is one of the most destructive insect pests of sorghum at the seedling stage. Deployment of cultivars with improved
shoot fly resistance would be facilitated by the use of molecular markers linked to QTL. The objective of this study was to
dissect the genetic basis of resistance into QTL, using replicated phenotypic data sets obtained from four test environments,
and a 162 microsatellite marker-based linkage map constructed using 168 RILs of the cross 296B (susceptible) × IS18551 (resistant).
Considering five component traits and four environments, a total of 29 QTL were detected by multiple QTL mapping (MQM) viz.,
four each for leaf glossiness and seedling vigor, seven for oviposition, six for deadhearts, two for adaxial trichome density
and six for abaxial trichome density. The LOD and R
2 (%) values of QTL ranged from 2.6 to 15.0 and 5.0 to 33%, respectively. For most of the QTL, IS18551 contributed resistance
alleles; however, at six QTL, alleles from 296B also contributed to resistance. QTL of the related component traits were co-localized,
suggesting pleiotropy or tight linkage of genes. The new morphological marker Trit for trichome type was associated with the major QTL for component traits of resistance. Interestingly, QTL identified in
this study correspond to QTL/genes for insect resistance at the syntenic maize genomic regions, suggesting the conservation
of insect resistance loci between these crops. For majority of the QTL, possible candidate genes lie within or very near the
ascribed confidence intervals in sorghum. Finally, the QTL identified in the study should provide a foundation for marker-assisted
selection (MAS) programs for improving shoot fly resistance in sorghum. 相似文献
16.
千粒重是油菜重要的产量相关性状之一,构建油菜遗传连锁图谱是研究其产量性状基因的前提。本研究利用小孢子培养技术,选育出了甘蓝型油菜大粒品系(G-42)和小粒品系(7-9)的纯合DH系DH-G-42和DH-7-9,其千粒重分别为6.24 g和2.42 g,二者比值达2.58。以DH-G-42为母本、DH-7-9为父本,构建了含190个单株的F2遗传作图群体,利用SSR和SRAP标记技术绘制遗传连锁图谱,该图谱共包含20个连锁群,涉及128个SSR标记和100个SRAP标记,图谱总长1546.6cM,标记间平均图距为6.78cM。本研究共检测到3个与千粒重性状相关的QTL,分别位于A9和C1连锁群,其中qSW-A9-1和qSW-A9-2贡献率分别达到10.98%和27.45%,均可视为控制粒重的主效QTL。本研究为后续进行油菜千粒重性状QTL的精细定位分析、分子标记辅助选择育种及新基因的克隆等奠定了基础。 相似文献
17.
Shahjahan Ali Desalegn D. Serba Jerry Jenkins Soonil Kwon Jeremy Schmutz Malay C. Saha 《Global Change Biology Bioenergy》2019,11(5):672-690
Switchgrass (Panicum virgatum L.), a native warm‐season perennial grass, is being considered as a feedstock for biofuel production in the United States. To expedite its genetic improvement and enhance genetic gain per selection cycle, application of marker‐assisted selection is indispensable. A high‐density linkage map was constructed in a pseudo‐F1 testcross mapping population of AP13×VS16, consisting of 349 progenies. A total of 8,757 single nucleotide polymorphism (SNP) markers generated through genotype‐by‐sequencing (GBS) were used to construct the linkage map. The total map length spans up to 2,540.2 cM with the marker density of one marker in every 0.25–0.34 cM. Spring green‐up (SG), days to flowering (FL), and the vegetative growth period (VP) data were analyzed and used for quantitative trait loci (QTL) mapping. The population showed significant variations and exhibited transgressive segregation for SG, FL, and VP. QTL analyses were performed using trait mean of each year and location along with BLUP (best linear unbiased prediction) values of the traits. A total of 35, 37, and 34 QTL for SG, FL, and VP, respectively, were identified. Phenotypic variability explained by each QTL ranged from 11.29% to 27.85%. The additive genetic effects of individual QTL ranged from ?1.81 to 2.40, ?6.12 to 7.58, and ?16.01 to 6.38 for SG, FL, and VP, respectively. Comparing major QTL regions in the switchgrass genome, 20 candidate genes were identified which were reported to be involved in growth‐, development‐, and flowering‐related traits in switchgrass. 相似文献
18.
The Pacific oyster (Crassostrea gigas) is one of the most important oysters cultured worldwide. To analyze the oyster genome and dissect growth-related traits,
we constructed a sex-averaged linkage map by combining 64 genomic simple sequence repeats, 42 expressed sequence tag-derived
SSRs, and 320 amplified fragment length polymorphism markers in an F1 full-sib family. A total of 426 markers were assigned to 11 linkage groups, spanning 558.2 cM with an average interval of
1.3 cM and 94.7% of genome coverage. Segregation distortion was significant for 18.8% of the markers (P < 0.05), and distorted markers tended to occur on some genetic regions or linkage groups. Most growth-related quantitative
traits were highly significantly (P < 0.01) correlated, and principal component analysis obtained four principal components. Quantitative trait locus (QTL) analysis
identified three significant QTLs for two principal components, which explained 0.6–13.9% of the phenotypic variation. One
QTL for sex was detected on linkage group 6, and the inheritabilities of sex for parental alleles and maternal alleles on
that locus C15 are 39.8% and 0.01%, respectively. The constructed linkage map and determined QTLs can provide a tool for further
genetic analysis of the traits and be potential for marker-assisted selection in C. gigas breeding. 相似文献
19.
Mapping of quantitative trait loci for kernel row number in maize across seven environments 总被引:3,自引:0,他引:3
Ming Lu Chuan-Xiao Xie Xin-Hai Li Zhuan-Fang Hao Ming-Shun Li Jian-Feng Weng De-Gui Zhang Li Bai Shi-Huang Zhang 《Molecular breeding : new strategies in plant improvement》2011,28(2):143-152
Genetic factors controlling quantitative inheritance of grain yield and its components have been intensively investigated
during recent decades using diverse populations in maize (Zea mays L.). Notwithstanding this, quantitative trait loci (QTL) for kernel row number (KRN) with large and consistent effect have
not been identified. In this study, a linkage map of 150 simple sequence repeat (SSR) loci was constructed by using a population
of 500 F2 individuals derived from a cross between elite inbreds Ye478 and Dan340. The linkage map spanned a total of 1478 cM
with an average interval of 10.0 cM. A total of 397 F2:3 lines were evaluated across seven diverse environments for mapping
QTL for KRN. Some QTL for grain yield and its components had previously been confirmed with this population across environments.
A total of 13 QTL for KRN were identified, with each QTL explaining from 3.0 to 17.9% of phenotypic variance. The gene action
for KRN was mainly additive to partial dominance. A large-effect QTL (qkrn7) with partial dominance effect accounting for 17.9% of the phenotypic variation for KRN was identified on chromosome 7 near
marker umc1865 with consistent gene effect across seven diverse environments. This study has laid a foundation for map-based
cloning of this major QTL and for developing molecular markers for marker-assisted selection of high KRN. 相似文献
20.
A genome‐wide association study of 2098 progeny‐tested Nordic Holstein bulls genotyped for 36 387 SNPs on 29 autosomes was conducted to confirm and fine‐map quantitative trait loci (QTL) for mastitis traits identified earlier using linkage analysis with sparse microsatellite markers in the same population. We used linear mixed model analysis where a polygenic genetic effect was fitted as a random effect and single SNPs were successively included as fixed effects in the model. We detected 143 SNP‐by‐trait significant associations (P < 0.0001) on 20 chromosomes affecting mastitis‐related traits. Among them, 21 SNP‐by‐trait combinations exceeded the genome‐wide significant threshold. For 12 chromosomes, both the present association study and the previous linkage study detected QTL, and of these, six were in the same chromosomal locations. Strong associations of SNPs with mastitis traits were observed on bovine autosomes 6, 13, 14 and 20. Possible candidate genes for these QTL were identified. Identification of SNPs in linkage disequilibrium with QTL will enable marker‐based selection for mastitis resistance. The candidate genes identified should be further studied to detect candidate polymorphisms underlying these QTL. 相似文献