共查询到20条相似文献,搜索用时 31 毫秒
1.
K. C. Falke H. P. Maurer A. E. Melchinger H.- P. Piepho C. Flachenecker M. Frisch 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(2):289-297
According to quantitative genetic theory, linkage disequilibrium (LD) can hamper the short- and long-term selection response in recurrent selection (RS) programs. We analyzed LD in two European flint maize populations, KW1265 × D146 (A × B) and D145 × KW1292 (C × D), under modified recurrent full-sib selection. Our objectives were to investigate (1) the decay of initial parental LD present in F2 populations by three generations of intermating, (2) the generation of new LD in four (A × B) and seven (C × D) selection cycles, and (3) the relationship between LD changes and estimates of the additive genetic variance. We analyzed the F2 and the intermated populations as well as all selection cycles with 104 (A × B) and 101 (C × D) simple sequence repeat (SSR) markers with a uniform coverage of the entire maize genome. The LD coefficient D and the composite LD measure Δ were estimated and significance tests for LD were performed. LD was reduced by intermating as expected from theory. A directional generation of negative LD between favorable alleles could not be observed during the selection cycles. However, considerable undirectional changes in D were observed, which we attributed to genetic sampling due to the finite population size used for recombination. Consequently, a long-term reduction of the additive genetic variance due to negative LD was not observed. Our experimental results support the hypothesis that in practical RS programs with maize, LD generated by selection is not a limiting factor for obtaining a high selection response. 相似文献
2.
Shi Zhenjie Zheng Qianjiao Sun Xiaoyang Xie Fuchun Zhao Jian Zhang Gaoyun Zhao Wei Guo Zhixin Ariunzul Ariuka Fahad Shah Adnan Muhammad Qin Dong Saud Shah Yajun Chen 《BMC plant biology》2020,20(1):1-15
Kernel weight and morphology are important traits affecting cereal yields and quality. Dissecting the genetic basis of thousand kernel weight (TKW) and its related traits is an effective method to improve wheat yield. In this study, we performed quantitative trait loci (QTL) analysis using recombinant inbred lines derived from the cross ‘PuBing3228 × Gao8901’ (PG-RIL) to dissect the genetic basis of kernel traits. A total of 17 stable QTLs related to kernel traits were identified, notably, two stable QTLs QTkw.cas-1A.2 and QTkw.cas-4A explained the largest portion of the phenotypic variance for TKW and kernel length (KL), and the other two stable QTLs QTkw.cas-6A.1 and QTkw.cas-7D.2 contributed more effects on kernel width (KW). Conditional QTL analysis revealed that the stable QTLs for TKW were mainly affected by KW. The QTLs QTkw.cas-7D.2 and QKw.cas-7D.1 associated with TKW and KW were delimited to the physical interval of approximately 3.82 Mb harboring 47 candidate genes. Among them, the candidate gene TaFT-D1 had a 1 bp insertions/deletion (InDel) within the third exon, which might be the reason for diversity in TKW and KW between the two parents. A Kompetitive Allele-Specific PCR (KASP) marker of TaFT-D1 allele was developed and verified by PG-RIL and a natural population consisted of 141 cultivar/lines. It was found that the favorable TaFT-D1 (G)-allele has been positively selected during Chinese wheat breeding. Thus, these results can be used for further positional cloning and marker-assisted selection in wheat breeding programs. Seventeen stable QTLs related to kernel traits were identified. The stable QTLs for thousand kernel weight were mainly affected by kernel width. TaFT-D1 could be the candidate gene for QTLs QTkw.cas-7D.2 and QKw.cas-7D.1. 相似文献
3.
Milena de Luna Alves Lima Cláudio Lopes de Souza Jr Dyeme Antonio Vieira Bento Anete Pereira de Souza Luciana Aparecida Carlini-Garcia 《Molecular breeding : new strategies in plant improvement》2006,17(3):227-239
The vast majority of reported QTL mapping for maize (Zea mays L.) traits are from temperate germplasm and, also, QTL by environment interaction (QTL × E) has not been thoroughly evaluated
and analyzed in most of these papers. The maize growing areas in tropical regions are more prone to environmental variability
than in temperate areas, and, therefore, genotype by environment interaction is of great concern for maize breeders. The objectives
of this study were to map QTL and to test their interaction with environments for several traits in a tropical maize population.
Two-hundred and fifty-six F2:3 families evaluated in five environments, a genetic map with 139 microsatellites markers, and the multiple-environment joint
analysis (mCIM) were used to map QTL and to test QTL × E interaction. Sixteen, eight, six, six, nine, and two QTL were mapped
for grain yield, ears per plant, plant lodging, plant height, ear height, and number of leaves, respectively. Most of these
QTL interacted significantly with environments, most of them displayed overdominance for all traits, and genetic correlated
traits had a low number of QTL mapped in the same genomic regions. Few of the QTL mapped had already been reported in both
temperate and tropical germplasm. The low number of stable QTL across environments imposes additional challenges to design
marker-assisted selection in tropical areas, unless the breeding programs could be directed towards specific target areas. 相似文献
4.
Falke KC Maurer HP Melchinger AE Piepho H Flachenecker C Frisch M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(2):299-297
According to quantitative genetic theory, linkage disequilibrium (LD) can hamper the short- and long-term selection response in recurrent selection (RS) programs. We analyzed LD in two European flint maize populations, KW1265 x D146 (A x B) and D145 x KW1292 (C x D), under modified recurrent full-sib selection. Our objectives were to investigate (1) the decay of initial parental LD present in F(2) populations by three generations of intermating, (2) the generation of new LD in four (A x B) and seven (C x D) selection cycles, and (3) the relationship between LD changes and estimates of the additive genetic variance. We analyzed the F(2) and the intermated populations as well as all selection cycles with 104 (A x B) and 101 (C x D) simple sequence repeat (SSR) markers with a uniform coverage of the entire maize genome. The LD coefficient D and the composite LD measure Delta were estimated and significance tests for LD were performed. LD was reduced by intermating as expected from theory. A directional generation of negative LD between favorable alleles could not be observed during the selection cycles. However, considerable undirectional changes in D were observed, which we attributed to genetic sampling due to the finite population size used for recombination. Consequently, a long-term reduction of the additive genetic variance due to negative LD was not observed. Our experimental results support the hypothesis that in practical RS programs with maize, LD generated by selection is not a limiting factor for obtaining a high selection response. 相似文献
5.
Virginie Mérot-L’Anthoëne Brigitte Mangin Florent Lefebvre-Pautigny Sylvain Jasson Michel Rigoreau Jwanro Husson Charles Lambot Dominique Crouzillat 《Tree Genetics & Genomes》2014,10(6):1541-1553
Coffea canephora is subject to enormous competitive challenges from other crops, especially for farmer sustainability and consumer requirements. Coffee breeding programs have to focus on specific traits linked to these two key targets, such as quality character, largely depending on the bean’s biochemical composition and field yield. Two segregating populations A and B, from crosses between a hybrid (Congolese?×?Guinean) FRT58 parental clone and a Congolese FRT51 genotype and between two Congolese parents FRT67 and FRT51, respectively, were used to characterize the quantitative trait loci (QTL) involved in agronomic and biochemical traits. A consensus genetic map was established using 249 SSRs covering 1,201 cM. Three QTL detection models per population with MapQTL (model I) and MCQTL (model II) followed by a connected population approach with MCQTL (model III) were compared based on their efficiency, precision for QTL detection, and their genetic effect assessment (additive, dominance, and parental-favorable allele). The analysis detected a total of 143 QTLs, 60 of which were shared between the three models; 28 found with two models; and two, 13, and 40 specific from models I, II, and III, respectively. The last model III based on connected populations is much more efficient in detecting QTLs with low variance explained and led to the genetic characterization of favorable allele. Thanks to this comparison of three QTL detection models on our quantitative genetic study, we will give a new insight for coffee breeding programs dedicated to managing complex agronomic or qualitative traits. 相似文献
6.
Fruit quality and repeat flowering are two major foci of several strawberry breeding programs. The identification of quantitative trait loci (QTL) and molecular markers linked to these traits could improve breeding efficiency. In this work, an F1 population derived from the cross ‘Delmarvel’ × ‘Selva’ was used to develop a genetic linkage map for QTL analyses of fruit-quality traits and number of weeks of flowering. Some QTL for fruit-quality traits were identified on the same homoeologous groups found in previous studies, supporting trait association in multiple genetic backgrounds and utility in multiple breeding programs. None of the QTL for soluble solids colocated with a QTL for titratable acids, and, although the total soluble solid contents were significantly and positively correlated with titratable acids, the correlation coefficient value of 0.2452 and independence of QTL indicate that selection for high soluble solids can be practiced independently of selection for low acidity. One genomic region associated with the total number of weeks of flowering was identified quantitatively on LG IV-S-1. The most significant marker, FxaACAO2I8C-145S, explained 43.3 % of the phenotypic variation. The repeat-flowering trait, scored qualitatively, mapped to the same region as the QTL. Dominance of the repeat-flowering allele was demonstrated by the determination that the repeat-flowering parent was heterozygous. This genomic region appears to be the same region identified in multiple mapping populations and testing environments. Markers linked in multiple populations and testing environments to fruit-quality traits and repeat flowering should be tested widely for use in marker-assisted breeding. 相似文献
7.
Baumgarten AM Suresh J May G Phillips RL 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(7):1229-1238
Quantitative trait loci (QTL) contributing to the frequency and severity of Ustilago maydis infection in the leaf, ear, stalk, and tassel of maize plants were mapped using an A188 × CMV3 and W23 × CMV3 recombinant
inbred (RI) populations. QTLs mapped to genetic bins 2.04 and 9.04–9.05 of the maize genome contributed strongly (R
2 = 18–28%) to variation in the frequency and severity of U. maydis infection over the entire plant in both populations and within the majority of environments. QTLs mapped to bins 3.05, 3.08,
and 8.00 in the A188 × CMV3 population and bin 4.05 in both populations significantly contributed to the frequency or severity
of infection in only the tassel tissue. QTLs mapped to bin 1.07 in the A188 × CMV3 population and bin 7.00 in the W23 × CMV3
population contributed to U. maydis resistance in only the ear tissue. Interestingly, the CMV3 allele of the QTL mapped to bin 1.10 in the A188 × CMV3 population
significantly contributed to U. maydis susceptibility in the ear and stalk but significantly increased resistance in the tassel tissue. Digenic epistatic interactions
between the QTL mapped to bin 5.08 and four distinct QTLs significantly contributed to the frequency and severity of infection
over the entire plant and within the tassel tissue of the A188 × CMV3 population. Several QTLs detected in this study mapped
to regions of the maize genome containing previously mapped U. maydis resistance QTLs and genes involved in plant disease resistance.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
J. M. Soriano E. M. Vera-Ruiz S. Vilanova J. Martínez-Calvo G. Llácer M. L. Badenes C. Romero 《Tree Genetics & Genomes》2008,4(3):391-402
Sharka disease, caused by the plum pox virus (PPV), is one of the major limiting factors for stone fruit crops in Europe and
America. In particular, apricot is severely affected suffering significant fruit losses. Thus, PPV resistance is a trait of
great interest for the apricot breeding programs currently in progress. In this work, two apricot maps, earlier constructed
with the F1 ‘Goldrich × Currot’ (G×C) and the F2 ‘Lito × Lito’-98 (L×L-98) populations, have been improved including 43 and 37 new simple sequence repeat (SSR) loci, respectively,
to facilitate PPV resistance trait mapping. Screening of PPV resistance on the segregating populations classified seedling
phenotypes into resistant or susceptible. A non-parametric mapping method, based on the Kruskal–Wallis (KW) rank sum test,
was initially used to score marker–trait association, and results were confirmed by interval mapping. Contrary to the putative
digenic model inferred from the phenotypic segregations, all significant markers for the KW statistic (P < 0.005) mapped in a unique region of ~21.0 and ~20.3 cM located on the upper part of the G1 linkage group in ‘G×C’ and ‘L×L-98’
maps, respectively. According to the data, PPV resistance is suggested to be controlled by at least one major dominant locus.
The association between three SSRs distributed within this region and the PPV resistance was tested in two additional populations
(‘Goldrich × Canino’ and ‘Lito × Lito’-00) and breeding program parents. The marker ssrPaCITA5 showed the highest KW value
(P < 0.005) in all cases, pointing out its usefulness in marker-assisted selection.
Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Fusarium head blight (FHB) is one of the most devastating wheat diseases, causing both yield loss and quality reduction. To detect
quantitative trait loci (QTL) responsible for FHB resistance, plants of the F
2:3 population derived from a ‘Wangshui-bai’ × ‘Sy95-7’ cross were artificially inoculated. Of 396 simple sequence repeats (SSRs),
125 amplified fragment length polymorphisms were used for FHB resistance QTL analysis. Five QTLs for FHB resistance were detected
on chromosomes 3B, 6B, 7A, 1B and 2D. The effect of the QTL located on chromosome 3B on phenotypic variation was 31.69%, while
that of the QTL found on 2D was the smallest and only accounted for 4.98% of the variation. The resistance alleles originated
from ‘Wangshibai’ and association of the QTLs using these SSR markers may facilitate marker-assisted selection to improve
FHB resistance in the wheat breeding programs of southwest China. 相似文献
10.
Laperche A Brancourt-Hulmel M Heumez E Gardet O Hanocq E Devienne-Barret F Le Gouis J 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(3):399-415
Lower market prices and environmental concerns now orientate wheat (Triticum aestivum L.) breeding programs towards low input agricultural practices, and more particularly low nitrogen (N) input management.
Such programs require knowledge of the genetic determination of plant reaction to N deficiency. Our aim was to characterize
the genetic basis of N use efficiency and genotype × N interactions. The detection of QTL for grain yield, grain protein yield
and their components was performed on a mapping population of 222 doubled haploid lines (DH), obtained from the cross between
an N stress tolerant variety and an N stress sensitive variety. Experiments on the population were carried out in seven different
environments, and in each case under high (N+) and low (N−) N supplies. In total, 233 QTL were detected for traits measured in each combination of environment and N supply, for “global”
interaction variables (N+–N− and N−/N+), for sensitivity to N stress and for performance under N-limited conditions which were assessed using factorial regression
parameters. The 233 QTL were detected on the whole genome and clustered into 82 genome regions. The dwarfing gene (Rht-B1), the photoperiod sensitivity gene (Ppd-D1) and the awns inhibitor gene (B1) coincided with regions that contained the highest numbers of QTL. Non-interactive QTL were detected on linkage groups 3D,
4B, 5A1 and 7B2. Interactive QTL were revealed by interaction or factorial regression variables (2D2, 3D, 5A1, 5D, 6A, 6B,
7B2) or by both variables (1B, 2A1, 2A2, 2D1, 4B, 5A2, 5B). The usefulness of QTL meta-analysis and factorial regression to
study QTL × N interactions and the impact of Rht-B1, Ppd-D1 and B1, are discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
Quantitative trait loci for aluminum resistance in wheat 总被引:4,自引:0,他引:4
Li-Li Zhou Gui-Hua Bai Hong-Xiang Ma Brett F. Carver 《Molecular breeding : new strategies in plant improvement》2007,19(2):153-161
Quantitative trait loci (QTL) for wheat resistance to aluminum (Al) toxicity were analyzed using simple sequence repeats (SSRs)
in a population of 192 F6 recombinant inbred lines (RILs) derived from a cross between an Al-resistant cultivar, Atlas 66 and an Al-sensitive cultivar,
Chisholm. Wheat reaction to Al was measured by relative root growth and root response to hematoxylin stain in nutrient-solution
culture. After screening 1,028 SSR markers for polymorphisms between the parents and bulks, we identified two QTLs for Al
resistance in Atlas 66. One major QTL was mapped on chromosome 4D that co-segregated with the Al-activated malate transporter
gene (ALMT1). Another minor QTL was located on chromosome 3BL. Together, these two QTLs accounted for about 57% of the phenotypic variation
in hematoxylin staining score and 50% of the variation in net root growth (NRG). Expression of the minor QTL on 3BL was suppressed
by the major QTL on 4DL. The two QTLs for Al resistance in Atlas 66 were also verified in an additional RIL population derived
from Atlas 66/Century. Several SSR markers closely linked to the QTLs were identified and have potential to be used for marker-assisted
selection (MAS) to improve Al-resistance of wheat cultivars in breeding programs. 相似文献
12.
The genetic basis of body weight in the mouse was investigated by measuring frequency changes of microsatellite marker alleles in lines divergently selected for body weight from a base population of a cross between two inbred strains. In several regions of the genome, sharp peaks of frequency change at linked markers were detected, which suggested the presence of single genes of moderate effect, although in several other regions, significant frequency changes occurred over large portions of chromosomes. A method based on maximum likelihood was used to infer effects and map positions of quantitative trait loci (QTLs) based on genotype frequencies at one or more marker loci. Eleven QTLs with effects in the range 0.17-0.28 phenotypic standard deviations were detected; but under an additive model, these did not fully account for the observed selection response. Tests for the presence of more than one QTL in regions where there were large changes of marker allele frequency were mostly inconclusive. 相似文献
13.
Gulay Mann Simon Diffey Brian Cullis Fermin Azanza David Martin Alison Kelly Lynne McIntyre Adele Schmidt Wujun Ma Zena Nath Ibrahim Kutty P. Emmett Leyne Lynette Rampling Ken J. Quail Matthew K. Morell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(8):1519-1537
While the genetic control of wheat processing characteristics such as dough rheology is well understood, limited information
is available concerning the genetic control of baking parameters, particularly sponge and dough (S&D) baking. In this study,
a quantitative trait loci (QTL) analysis was performed using a population of doubled haploid lines derived from a cross between
Australian cultivars Kukri × Janz grown at sites across different Australian wheat production zones (Queensland in 2001 and
2002 and Southern and Northern New South Wales in 2003) in order to examine the genetic control of protein content, protein
expression, dough rheology and sponge and dough baking performance. The study highlighted the inconsistent genetic control
of protein content across the test sites, with only two loci (3A and 7A) showing QTL at three of the five sites. Dough rheology
QTL were highly consistent across the 5 sites, with major effects associated with the Glu-B1 and Glu-D1 loci. The Glu-D1 5 + 10 allele had consistent effects on S&D properties across sites; however, there was no evidence for a positive effect
of the high dough strength Glu-B1-al allele at Glu-B1. A second locus on 5D had positive effects on S&D baking at three of five sites. This study demonstrated that dough rheology
measurements were poor predictors of S&D quality. In the absence of robust predictive tests, high heritability values for
S&D demonstrate that direct selection is the current best option for achieving genetic gain in this product category.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
C.-G. Chu S. S. Xu T. L. Friesen J. D. Faris 《Molecular breeding : new strategies in plant improvement》2008,22(2):251-266
Genetic maps are useful for detecting quantitative trait loci (QTL) associated with quantitative traits and for marker-assisted
selection (MAS) in breeding. In this research, we used the wheat × maize method to develop a doubled haploid (DH) population
derived from the synthetic hexaploid wheat (SHW) line TA4152-60 and the North Dakota hard red spring wheat line ND495. The
population consisted of 213 lines, of which a subset of 120 lines was randomly selected and used to construct linkage maps
of all 21 chromosomes and for QTL detection. The whole genome maps consisted of 632 markers including 410 SSRs, 218 TRAPs,
1 RFLP, and 3 phenotypic markers, and spanned 3,811.5 cM with an average density of one marker per 6.03 cM. Telomere sequence-based
TRAPs allowed us to define the ends of seven linkage groups. Analysis revealed major QTLs associated with the traits of days
to heading on chromosomes 5A and 5B, plant height on chromosomes 4D and 5A, and spike characteristics on chromosomes 3D, 4A,
4D, 5A and 5B. The DH population and genetic map will be a useful tool for the identification of disease resistance QTL and
agronomically important loci, and will aid in the identification and development of markers for MAS.
Mention of trade names or commercial products in this article is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the U.S. Department of Agriculture. 相似文献
15.
不同QTL增效基因初始频率下标记辅助选择的效果 总被引:1,自引:0,他引:1
采用随机模拟方法模拟了在一个闭锁群体内连续对单个性状选择10个世代的情形。在假定选择性状受一个位于常染色体上的QTL和多基因共同控制的情况下,采用动物模型标记辅助最佳线性无偏预测方法估计个体育种值并据此进行种畜的选留,并在此基础上系统地比较了QTL增效基因初始频率对标记辅助选择效果的影响。结果表明:当群体中QTL增效基因的初始频率较低时,选择所获得的QTL基因型值的进展会更大,标记辅助选择在单位时间内可获得较大的遗传进展;此时,尽管QTL增效基因在群体中固定所需的世代数会更长一些,但其频率上升的速度却更快。而QTL增效基因初始频率的高低对群体近交增量的影响不是很大。 相似文献
16.
Fan Z Robbins MD Staub JE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(5):843-855
Cucumber (Cucumis sativus L.; 2n=2x=14) has a narrow genetic base, and commercial yield of US processing cucumber has plateaued in the last 15 years. Yield may
be increased by altering plant architecture to produce unique early flowering (days to flower, DTF), female (gynoecious, GYN),
highly branched (multiple lateral branching, MLB), long-fruited (length:diameter ratio, L:D) cultivars with diverse plant
statures. The genetic map position of QTL conditioning these quantitatively inherited yield component traits is known, and
linked molecular markers may have utility in marker-assisted selection (MAS) programs to increase selection efficiency, and
effectiveness. Therefore, a base population (C0), created by intermating four unique but complementary lines, was subjected to three cycles (C1–C3) of phenotypic (PHE) mass selection for DTF, GYN, MLB, and L:D. In tandem, two cycles of marker-assisted backcrossing for
these traits began with selected C2 progeny (C2S) to produce families (F1[i.e., C2S × C2S], and BC1 [i.e., F1 × C2S]) for line extraction, and for comparative analysis of gain from selection by PHE selection, and MAS. Frequencies of marker
loci were used to monitor selection-dependent changes during PHE selection, and MAS. Similar gain from selection was detected
as a result of PHE selection, and MAS for MLB (~0.3 branches/cycle), and L:D (~0.1 unit increase/cycle) with concomitant changes
in frequency at linked marker loci. Although genetic gain was not realized for GYN during PHE selection, the percentage of
female flowers of plants subjected to MAS was increased (5.6–9.8% per cycle) depending upon the BC1 population examined. Selection-dependent changes in frequency were also detected at marker loci linked to female sex expression
during MAS. MAS operated to fix favorable alleles that were not exploited by PHE selection in this population, indicating
that MAS could be applied for altering plant architecture in cucumber to improve its yield potential.
The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper
therefore must be hereby, marked advertisement solely to indicate this fact. Mention of a trade name, proprietary product,
or specific equipment does not constitute a guarantee or warranty by the USDA and does not imply its approval to the exclusion
of other products that may be suitable. 相似文献
17.
A simple model based on one single identified quantitative trait locus (QTL) in a two-way crossing system was used to demonstrate the power of mate selection algorithms as a natural means of opportunistic line development for optimization of crossbreeding programs over multiple generations. Mate selection automatically invokes divergent selection in two parental lines for an over-dominant QTL and increased frequency of the favorable allele toward fixation in the sire-line for a fully-dominant QTL. It was concluded that an optimal strategy of line development could be found by mate selection algorithms for a given set of parameters such as genetic model of QTL, breeding objective and initial frequency of the favorable allele in the base populations, etc. The same framework could be used in other scenarios, such as programs involving crossing to exploit breed effects and heterosis. In contrast to classical index selection, this approach to mate selection can optimize long-term responses. 相似文献
18.
Piotr Masojć Paweł Milczarski 《Molecular breeding : new strategies in plant improvement》2009,23(1):75-84
Preharvest sprouting (PHS) and high alpha-amylase activity (AA) negatively affect quality of rye grain. The objective of this
study was to reveal genetic relationship between PHS and AA by developing a consensus map of QTLs controlling each trait.
A method of composite interval mapping (CIM) was used to search for QTLs within the 541 × Ot1-3 and DS2 × RXL10 F2 mapping populations representing wide variation range of both traits. Sixteen QTLs for AA were detected on chromosomes 1R
(3), 2R (2), 3R (2), 4R (3), 5R (3), 6R (2) and 7R (1). Their distribution was not random showing a tendency of QTL location
in distal regions of chromosomes. Nine QTLs for AA located on chromosome arms 1RS, 2RL, 3RS, 4RL, 5RS, 5RL, 6RS, 6RL and 7RS
coincided with QTLs for PHS. Seven QTLs for AA independent from PHS were detected on chromosome arms 1RL (2), 2RS, 3RL, 4RS,
4RL and 5RL. Four QTLs for PHS not associated with those for AA were identified on chromosomes 1RL, 2RL, 5RL and 7RL. Partial
overlapping of the genetic systems controlling AA and PHS suggests that alpha-amylase found in sound grain of rye could be
produced through at least three independent mechanisms i.e. PHS at its initial stage, late maturity alpha-amylase (LMA) and/or
retained pericarp alpha-amylase (RPAA). Six QTLs co-located on both maps were found on chromosome arms 1RS, 2RS, 5RS, 5RL,
6RS and 6RL. Valuable features of line Ot1-3 i.e. resistance to preharvest sprouting and low alpha-amylase production in ripening
grain can be attributed to seven major QTLs from chromosomes 1RL, 2RL, 5RL (2), 6RL and 7R (2). This set of QTLs, identified
in line Ot1-3, might be useful in breeding sprouting resistant cultivars of rye. 相似文献
19.
Genome‐wide analysis of allele frequency change in sunflower crop–wild hybrid populations evolving under natural conditions
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Jonathan Corbi Eric J. Baack Jennifer M. Dechaine Gerald Seiler John M. Burke 《Molecular ecology》2018,27(1):233-247
Crop‐wild hybridization occurs in numerous plant species and could alter the genetic structure and evolutionary dynamics of wild populations. Studying crop‐derived alleles in wild populations is also relevant to assessing/mitigating the risks associated with transgene escape. To date, crop‐wild hybridization has generally been examined via short‐term studies, typically within a single generation, focusing on few traits or genetic markers. Little is known about patterns of selection on crop‐derived alleles over multiple generations, particularly at a genome‐wide scale. Here, we documented patterns of natural selection in an experimental crop × wild sunflower population that was allowed to evolve under natural conditions for two generations at two locations. Allele frequencies at a genome‐wide collection of SNPs were tracked across generations, and a common garden experiment was conducted to compare trait means between generations. These data allowed us to identify instances of selection on crop‐derived alleles/traits and, in concert with QTL mapping results, test for congruence between our genotypic and phenotypic results. We found that natural selection overwhelmingly favours wild alleles and phenotypes. However, crop alleles in certain genomic regions can be favoured, and these changes often occurred in parallel across locations. We did not, however, consistently observe close agreement between our genotypic and phenotypic results. For example, when a trait evolved towards the wild phenotype, wild QTL alleles associated with that trait did not consistently increase in frequency. We discuss these results in the context of crop allele introgression into wild populations and implications for the management of GM crops. 相似文献
20.
Valérie Loywyck Bertrand Bed'hom Marie-Hélène Pinard-van der Laan Frédérique Pitel étienne Verrier Piter Bijma 《遗传、选种与进化》2008,40(6):639-661
We investigated the joint evolution of neutral and selected genomic regions in three chicken lines selected for immune response and in one control line. We compared the evolution of polymorphism of 21 supposedly neutral microsatellite markers versus 30 microsatellite markers located in seven quantitative trait loci (QTL) regions. Divergence of lines was observed by factor analysis. Five supposedly neutral markers and 12 markers in theQTL regions showed Fst values greater than 0.15. However, the non-significant difference (P > 0.05) between matrices of genetic distances based on genotypes at supposedly neutral markers on the one hand, and at markers in QTL regions, on the other hand, showed that none of the markers in the QTL regions were influenced by selection. A supposedly neutral marker and a marker located in the QTL region on chromosome 14 showed temporal variations in allele frequencies that could not be explained by drift only. Finally, to confirm thatmarkers located inQTL regions on chromosomes 1, 7 and 14were under the influence of selection, simulations were performed using haplotype dropping along the existing pedigree. In the zone located on chromosome 14, the simulation results confirmed that selection had an effect on the evolution of polymorphism of markers within the zone. 相似文献