共查询到20条相似文献,搜索用时 765 毫秒
1.
Iruela M Rubio J Barro F Cubero JI Millán T Gil J 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(2):278-287
Two quantitative trait loci (QTLs), (QTLAR1 and QTLAR2) associated with resistance to ascochyta blight, caused by Ascochyta rabiei, have been identified in a recombinant inbred line population derived from a cross of kabuli×desi chickpea. The population
was evaluated in two cropping seasons under field conditions and the QTLs were found to be located in two different linkage
groups (LG4a and LG4b). LG4b was saturated with RAPD markers and four of them associated with resistance were sequenced to
give sequence characterized amplified regions (SCARs) that segregated with QTLAR2. This QTL explained 21% of the total phenotypic variation. However, QTLAR1, located in LG4a, explained around 34% of the total phenotypic variation in reaction to ascochyta blight when scored in the
second cropping season. This LG4a region only includes a few markers, the flower colour locus (B/b), STMS GAA47, a RAPD marker and an inter-simple-sequence-repeat and corresponds with a previously reported QTL. From the
four SCARs tagging QTLAR2, SCAR (SCY17590) was co-dominant, and the other three were dominant. All SCARs segregated in a 1:1 (presence:absence) ratio and the scoring
co-segregated with their respective RAPD markers. QTLAR2 on LG4b was mapped in a highly saturated genomic region covering a genetic distance of 0.8 cM with a cluster of nine markers
(three SCARs, two sequence-tagged microsatellite sites (STMS) and four RAPDs). Two of the four SCARs showed significant alignment
with genes or proteins related to disease resistance in other species and one of them (SCK13603) was sited in the highly saturated region linked to QTLAR2. STMS TA72 and TA146 located in LG4b were described in previous maps where QTL for blight resistance were also localized
in both inter and intraspecific crosses. These findings may improve the precision of molecular breeding for QTLAR2 as they will allow the choice of as much polymorphism as possible in any population and could be the starting point for finding
a candidate resistant gene for ascochyta blight resistance in chickpea. 相似文献
2.
M. M. Sewell D. L. Bassoni R. A. Megraw N. C. Wheeler D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(8):1273-1281
Physical wood property traits for loblolly pine (Pinus taeda L.) were analyzed for the presence of quantitative trait loci (QTLs) in a three-generation outbred pedigree. These traits
include wood specific gravity (wsg), volume percentage of latewood (vol%), and microfibril angle (mfa). Phenotypic data were collected for rings 2–11 for wsg and vol%, and rings 3, 5 and 7 for mfa. Both earlywood and latewood were analyzed for each trait. An interval mapping approach designed for an outbred pedigree
was used to estimate the number of QTLs, the magnitude of QTL effects, and their genomic position. Nine unique QTLs were detected
for composite traits (average of all rings) for wsg, five for vol%, and five for mfa. The majority of these QTLs were verified by analyses of individual-ring traits. Additional QTLs for each trait were also
detected by these individual-ring analyses. Most QTLs for wsg were specific to either earlywood or latewood, whereas each QTL for mfa was detected for both earlywood and latewood. Before these QTLs are utilized in a breeding program, they should be verified
in larger experiments and in different genetic and environmental backgrounds.
Received: 15 February 2000 / Accepted: 31 March 2000 相似文献
3.
R. García M. J. Asíns J. Forner E. A. Carbonell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):511-518
Propagation of citrus rootstocks depends upon the production of clonal plants from nucellar seedlings. This makes apomixis
one of the host important traits in breeding programs for citrus rootstocks. The genetic control of apomixis was studied in
a 50-tree progeny derived from the cross C. volkameriana×P. trifoliata using 69 molecular markers and bulked segregant analysis. The proportion of nucellar seedlings was estimated by isoenzymatic
analysis of 25 seedlings per tree for 2 consecutive years. The type of embryony (polyembryonic versus monoembryonic seeds)
was also determined for fruit-yielding trees. Separate genetic maps for each parental species were developed. The integration
and comparison of these maps could be accomplished using common multiallelic segregant loci. Differences in gene synteny between
the two species-specific genetic maps were shown. Important distortions in the segregation of markers at several genomic regions,
some of them also involving differences in the C-methylation pattern, have been observed, especially for the pollen parent.
Analysis of quantitative trait loci (QTLs) revealed the presence of six genomic positions (two in P. trifoliata and four in C. volkameriana) contributing individually up to 24% of the total variation for apomixis. Within the same species, QTLs with positive and
negative allele effects were present, even in the same linkage group. One of the markers associated to apomixis (Apo2) is also associated to embryony type. Therefore, the genetic control of apomictic reproduction found in citrus (nucellar
embryony) is quite complex compared to what has been reported for gametophytic apomixis. Molecular markers linked to QTLs
governing apomixis will be useful to assist selection of future apomictic rootstocks for citrus varieties.
Received: 30 November 1998 / Accepted: 28 December 1998 相似文献
4.
Molecular-marker analysis of quantitative traits for growth and development in juvenile apple trees 总被引:1,自引:0,他引:1
P. J. Conner S. K. Brown N. F. Weeden 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(8):1027-1035
Random amplified polymorphic DNAs (RAPDs) were used in combination with a double pseudo-testcross mapping strategy to estimate
the position and effects of quantitative trait loci (QTLs) for traits influencing juvenile tree growth and development in
two apple cultivars. The mapping population consisted of 172 F1 trees from a cross between the columnar mutant ‘Wijcik McIntosh’ and a standard form disease-resistant selection NY 75441-58.
Significant associations were found between markers and height increment, internode number, internode length, base diameter
increment, base diameter after 9 years of growth, branch number, and leaf break. The number of genomic regions associated
with each trait varied from one to eight. The amount of variation explained by linear regression on individual marker loci
(R2) ranged from 3.9 to 24.3%, with an average of 7%. Multiple regression using markers for each putative QTL explained from
6.6 to 41.6% of the phenotypic variation, with an average value of 24.3%. A large number of traits had significant variation
associated with the map position of the dominant columnar gene, Co. QTL stability over years was estimated by comparing the locations of putative QTLs for traits measured in multiple years.
The majority of genomic regions were associated with a trait in only a single year, although regions associated with a trait
in more than 1 year were also detected. The limitations of dominant markers and an outbred mapping pedigree for QTL analysis
are discussed.
Received: 27 August 1997 / Accepted: 10 February 1998 相似文献
5.
H. Yoshimaru K. Ohba K. Tsurumi N. Tomaru M. Murai Y. Mukai Y. Suyama Y. Tsumura T. Kawahara Y. Sakamaki 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(1-2):45-50
Quantitative traits, including juvenile growth, flower bearing and rooting ability, of a woody plant species, Cryptomeria japonica D. Don, were analyzed in a three-generation pedigree with 73 F2 progenies using a linkage map with 85 genetic markers (72 RFLP, 11 RAPD, one isozyme and one morphological loci). A cluster
of quantitative trait loci (QTLs) related to juvenile growth and female flower bearing was detected on linkage group 2. Some
of the influence of this cluster could be attributed to pleiotropic effects of a dwarf locus located in its vicinity. QTLs
related to male and female flower bearing were detected at different locations and showed different effects from each other,
suggesting that the genetic systems controlling male and female flowering are different. No large QTL affecting rooting ability
was detected in the material analyzed in this study.
Received: 15 December 1997 / Accepted: 4 February 1998 相似文献
6.
Sibylle Stoeckli Karsten Mody Andrea Patocchi Markus Kellerhals Silvia Dorn 《Tree Genetics & Genomes》2009,5(1):257-267
The aim of this study was to assess the genetic basis of rust mite (Aculus schlechtendali) resistance in apple (Malus × domestica). A. schlechtendali infestation of apple trees has increased as a consequence of reduced side effects of modern fungicides on rust mites. An
analysis of quantitative trait loci (QTLs) was carried out using linkage map data available for F1 progeny plants of the cultivars ‘Fiesta’ × ‘Discovery’. Apple trees representing 160 different genotypes were surveyed for
rust mite infestation, each at three different sites in two consecutive years. The distribution of rust mites on the individual
apple genotypes was aggregated and significantly affected by apple genotype and site. We identified two QTLs for A. schlechtendali resistance on linkage group 7 of ‘Fiesta’. The AFLP marker E35M42-0146 (20.2 cM) and the RAPD marker AE10-400 (45.8 cM) were
closest positioned to the QTLs and explained between 11.0% and 16.6% of the phenotypic variability. Additionally, putative
QTLs on the ‘Discovery’ chromosomes 4, 5 and 8 were detected. The SSR marker Hi03a10 identified to be associated to one of
the QTLs (AFLP marker E35M42-0146) was traced back in the ‘Fiesta’ pedigree to the apple cultivar ‘Wagener’. This marker may
facilitate the breeding of resistant apple cultivars by marker assisted selection. Furthermore, the genetic background of
rust mite resistance in existing cultivars can be evaluated by testing them for the identified SSR marker.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Sewell MM Davis MF Tuskan GA Wheeler NC Elam CC Bassoni DL Neale DB 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):214-222
Chemical wood property traits were analyzed for the presence of quantitative trait loci (QTLs) in a three-generation outbred
pedigree of loblolly pine (Pinus taeda L.). These traits were assayed using pyrolysis molecular beam mass spectrometry and include mass spectrum peak intensities
associated with carbohydrates, α-cellulose and hemicellulose sugars, and lignin. Models for projection to latent structures
(PLS) were used to also estimate the chemical composition of cell walls (i.e., α-cellulose, galactan and lignin) from mass
spectrum data using multivariate regression. Both earlywood and latewood fractions from the fifth annual ring were analyzed
for each trait. An interval mapping approach designed for an outbred pedigree was used to estimate the number of QTLs, the
magnitude of QTL effects, and their genomic position. Eight unique QTLs influencing cell wall chemistry were detected from
multiple peak intensities and/or PLS estimates using the one- and two-QTL models. Significant differences in chemical contents
were observed among the populations from North Carolina vs Oklahoma, and results from QTL×environment analyses suggest that
QTLs interact with environmental location. QTLs should be verified in larger experiments and in different genetic and environmental
backgrounds. QTL mapping will help towards eventually identifying genes having a major effect on chemical wood properties.
Received: 19 January 2001 / Accepted: 31 May 2001 相似文献
8.
Genetic mapping of QTLs affecting tree growth and architecture in Populus: implication for ideotype breeding 总被引:4,自引:0,他引:4
R. L. Wu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(3-4):447-457
A segregated F2 progeny derived from two highly divergent poplar species, Populus trichocarpa and P. deltoides, was used to evaluate the genetic basis of canopy structure and function in a clonally replicated plantation. The QTLs of
large effect on growth, branch, and leaf traits were identified using the Populus linkage map constructed by 343 molecular markers. Stem height and harvest index appeared to be under the control of few QTLs
with major effects, whereas variation in stem basal area, volume, and dry weight might be due to many more QTLs. Branch and
leaf traits on sylleptics tended to include more QTLs with major effects than those on proleptics. In the environment where
the pedigree was tested, sylleptics were very frequent in the P. trichocarpa parent but rare in the P. deltoides parent. For sylleptic traits for which two or more QTLs were identified, however, increases in the trait values were conditioned
not only by the P. trichocarpa alleles, but also by the P. deltoides alleles. Similar findings were found for traits on proleptics that were differently expressed between the two parents. For
both sylleptic and proleptic branch types, dominance (ranging from partial to over) was observed. The QTLs on specific linkage
groups were found to be responsible for relationships between stem growth and its developmental components. Similar QTL clustering
was also observed for morphological or developmental integration in poplar, i.e., traits with similar developmental origins
are more strongly correlated with one another than traits with different developmental origins. The implications of these
molecular genetic results for ideotype breeding of poplars are discussed.
Received: 15 July 1997/Accepted: 19 August 1997 相似文献
9.
Ravindra M. Patil Manoj D. Oak Shubhada A. Tamhankar Pierre Sourdille Veliventi S. Rao 《Molecular breeding : new strategies in plant improvement》2008,21(4):485-496
Yellow pigment content in durum wheat (Triticum turgidum L. ssp. durum) is an important criterion for both pasta bright yellow color and human health because of antioxidant properties of carotenoids
involved in this pigmentation. In the present study, QTLs for yellow pigment content in durum wheat were mapped in a population
of 140 RILs developed from a intraspecific cross between a released variety (PDW 233) and a landrace (Bhalegaon 4). This trait
was evaluated in one location for 3 years and in two more locations for one additional year (five different year × location
combinations further called “environments”). Yellow pigment content was highly heritable across the five different environments.
Analysis of variance showed the significant effect of genotype, environment and genotype × environment interaction on the
trait. Five different QTLs linked to yellow pigment content were identified on chromosome 1A, 3B, 5B, 7A and 7B across five
different environments. The strongest one located on the distal part of the long arm of chromosome 7A, QYp.macs-7A, explained 55.22% of the variation in the trait, while, remaining four QTLs explained 5–8.75% of phenotypic variation in
yellow pigment content. Marker analysis revealed significant association of one ISSR and one AFLP fragment with the trait.
These two markers were linked to the major QTL QYp.macs-7A and were converted into SCAR markers. These SCAR markers were further validated on another population as well as 38 diverse
genotypes so as to prove their potential in marker assisted selection. These markers will be very useful for the marker assisted
breeding of durum wheat for higher yellow pigment content. 相似文献
10.
Bo Zhang Chunfa Tong Tongming Yin Xinye Zhang Qiang Zhuge Minren Huang Mingxiu Wang Rongling Wu 《Tree Genetics & Genomes》2009,5(3):539-552
The capacity to root from cuttings is a key factor for the mass deployment of superior genotypes in clonal forestry. We studied
the genetic basis of rooting capacity by mapping quantitative trait loci (QTLs) that control growth rate and form of root
traits in a full-sib family of 93 hybrids derived from an interspecific cross between two Populus species, P. deltoides and P. euramericana. The hybrid family was typed for different marker systems (including SSRs, AFLPs, RAPDs, ISSRs, and SNPs), leading to the
construction of two linkage maps based on the female P. deltoides (D map) and male P. euramericana (E map) with a pseudotestcross mapping strategy. The two maps were scanned by functional mapping to detect QTLs that control
early growth trajectories of two rooting traits, maximal single-root length and the total number of roots per cutting, measured
at five time points in water culture. Of the six QTLs detected for these two growth traits, only one is segregating in P. deltoides with poor rooting capacity, while the other five are segregating in P. euramericana showing good rooting capacity. Tests with functional mapping suggest different developmental patterns of the genetic effects
of these root QTLs in time course. Five QTLs were detected to change their effects on root growth trajectories with time,
whereas one detected to affect root growth consistently in time course. Knowledge about the genetic and developmental control
mechanisms of root QTLs will have important implications for the genetic improvement of vegetative propagation traits in Populus. 相似文献
11.
K. D. Jermstad D. L. Bassoni N. C. Wheeler T. S. Anekonda S. N. Aitken W. T. Adams D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1152-1158
Quantitative trait loci (QTLs) affecting fall and spring cold-hardiness were identified in a three-generation outbred pedigree
of coastal Douglas-fir [Pseudotsuga meniziesii (Mirb.) Franco var. menziesii]. Eleven QTLs controlling fall cold-hardiness were detected on four linkage groups, and 15 QTLs controlling spring cold-hardiness
were detected on four linkage groups. Only one linkage group contained QTLs for both spring and fall cold-hardiness, and these
QTLs tended to map in close proximity to one another. Several QTLs were associated with hardiness in all three shoot tissues
assayed in the spring, supporting previous reports that there is synchronization of plant tissues during de-acclimatization.
For fall cold-hardiness, co-location of QTLs was not observed for the different tissues assayed, which is consistent with
previous reports of less synchronization of hardening in the fall. In several cases, QTLs for spring or fall cold-hardiness
mapped to the same location as QTLs controlling spring bud flush. QTL estimations, relative magnitudes of heritabilities,
and genetic correlations based on clonal data in this single full-sib family, supports conclusions about the genetic control
and relationships among cold-hardiness traits observed in population samples of Douglas-fir in previous studies.
Received: 20 July 2000 / Accepted: 19 October 2000 相似文献
12.
Sibylle Stoeckli Karsten Mody Cesare Gessler Andrea Patocchi Mauro Jermini Silvia Dorn 《Tree Genetics & Genomes》2008,4(4):833-847
The rosy apple aphid (Dysaphis plantaginea), the leaf-curling aphid (Dysaphis cf. devecta) and the green apple aphid (Aphis pomi) are widespread pest insects that reduce growth of leaves, fruits and shoots in apple (Malus × domestica). Aphid control in apple orchards is generally achieved by insecticides, but alternative management options like growing
resistant cultivars are needed for a more sustainable integrated pest management (IPM). A linkage map available for a segregating
F1-cross of the apple cultivars ‘Fiesta’ and ‘Discovery’ was used to investigate the genetic basis of resistance to aphids.
Aphid infestation and plant growth characteristics were repeatedly assessed for the same 160 apple genotypes in three different
environments and 2 consecutive years. We identified amplified fragment length polymorphism (AFLP) markers linked to quantitative
trait loci (QTLs) for resistance to D. plantaginea (‘Fiesta’ linkage group 17, locus 57.7, marker E33M35–0269; heritability: 28.3%), and to D. cf. devecta (‘Fiesta’ linkage group 7, locus 4.5, marker E32M39–0195; heritability: 50.2%). Interactions between aphid species, differences
in climatic conditions and the spatial distribution of aphid infestation were identified as possible factors impeding the
detection of QTLs. A pedigree analysis of simple sequence repeat (SSR) marker alleles closely associated with the QTL markers
revealed the presence of the alleles in other apple cultivars with reported aphid resistance (‘Wagener’, ‘Cox’s Orange Pippin’),
highlighting the genetic basis and also the potential for gene pyramiding of aphid resistance in apple. Finally, significant
QTLs for shoot length and stem diameter were identified, while there was no relationship between aphid resistance and plant
trait QTLs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
Robert Vincent J.M. West Marilyn A.L. Inai Shuji Caines Angela Arntzen Lauren Smith Jodee K. St.Clair Dina A. 《Molecular breeding : new strategies in plant improvement》2001,8(3):217-233
Blackmold, caused by the fungus Alternaria alternata, is a major ripe fruit disease of processing tomatoes. Previously, we found blackmold resistance in a wild tomato (Lycopersicon cheesmanii) and quantitative trait loci (QTL) for resistance were mapped in an interspecific population. Five QTLs were selected for introgression from L. cheesmanii into cultivated tomato using marker-assisted selection (MAS). Restriction fragment length polymorphism and PCR-based markers flanking, and within, the chromosomal regions containing QTLs were used for MAS during backcross and selfing generations. BC1 plants heterozygous at the QTLs, and subsequent BC1S1 and BC1S2 lines possessing different homozygous combinations of alleles at the target QTLs, were identified using DNA markers. Field experiments were conducted in 1998 (with 80 marker-selected BC1S2 lines) and 1999 (with 151 marker-selected BC1S2 and BC1S3 lines) at three California locations. Blackmold resistance was assessed during both years, and horticultural traits were evaluated in 1999. The BC1S2 and BC1S3 lines containing L. cheesmanii alleles at the QTLs were associated with a large genetic variance for resistance to blackmold and moderate heritability, suggesting that significant genetic gain may be achieved by selection in this genetic material. L. cheesmanii alleles at three of the five introgressed QTLs showed a significant, positive effect on blackmold resistance. A QTL on chromosome 2 had the largest positive effect on blackmold resistance, alone and in combination with other QTLs, and was also associated with earliness, a positive horticultural trait. The other four QTLs were associated primarily with negative horticultural traits. Fine mapping QTLs using near isogenic lines could help determine if such trait associations are due to linkage drag or pleiotropy. 相似文献
14.
Identification of QTLs related to cocoa resistance to three species of<Emphasis Type="Italic"> Phytophthora</Emphasis> 总被引:1,自引:0,他引:1
Risterucci AM Paulin D Ducamp M N'Goran JA Lanaud C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,108(1):168-174
This study aimed to compare the genetic control of cacao resistance to three species of Phytophthora: Phytophthora palmivora, Phytophthora megakarya and Phytophthora capsici. The study was conducted on 151 hybrid progenies created in Côte d'Ivoire and grown in a green-house in Montpellier. Phytophthora resistance was screened by leaf-test inoculation with two different strains per species. Selection of the best individuals for resistance to P. palmivora at a 10% selection rate, would lead to a genetic progress of 47% in the disease evaluation for this species and a genetic progress of 42% and 21% for the two other species. A genetic map with a total length of 682 cM was built with 213 markers, 190 AFLPs and 23 microsatellites. QTLs were identified using composite interval mapping. QTLs were found located in six genomic regions. One of these was detected with five strains belonging to the three Phytophthora species. Two other regions were detected with two or three strains of two different species. Three additional QTLs were detected for only one species of Phytophthora. Each QTL explained between 8 to 12% of the phenotypic variation. For each strain, between 11.5% to 27.5% of the total phenotypic variation could be explained by the QTLs identified. The identification of multiple QTLs involved in resistance to Phytophthora offers the possibility to improve durability of resistance in cocoa by a possible cumulation of many different resistance genes located in different chromosome regions using marker-aided selection.Communicated by H.F. Linskens 相似文献
15.
RFLP mapping of quantitative trait loci controlling abscisic acid concentration in leaves of drought-stressed maize (Zea mays L.) 总被引:7,自引:0,他引:7
R. Tuberosa M. C. Sanguineti P. Landi S. Salvi E. Casarini S. Conti 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(5-6):744-755
Abscisic acid (ABA) concentration in leaves of drought-stressed plants is a quantitatively inherited trait. In order to identify
quantitative trait loci (QTLs) controlling leaf ABA concentration (L-ABA) in maize, leaf samples were collected from 80 F3:4 families of the cross Os420 (high L-ABA)×IABO78 (low L-ABA) tested under drought conditions in field trials conducted over
2 years. In each year, leaf samples were collected at stem elongation and near anthesis. The genetic map obtained with 106
restriction fragment length polymorphism (RFLP) loci covered 1370 cM, which represented approximately 85% of the UMC maize
map. Sixteen different QTLs with a LOD>2.0 were revealed in at least one sampling. Across samplings, only four QTLs significantly
influenced L-ABA, accounting for 66% of the phenotypic variation and 76% of the genetic variation among families. At these
QTLs, the alleles which increased L-ABA were contributed by Os420. The two most important QTLs were mapped on chromosome 2
near csu133 and csu109a. The effects associated with the QTL near csu133 were more pronounced near anthesis. The support intervals of the four primary QTLs for L-ABA did not overlap the presumed
map position of mutants impaired in ABA biosynthesis.
Received: 27 January 1998 / Accepted: 22 April 1998 相似文献
16.
Apple tree architecture is naturally very diverse, but for fruit production, certain tree habits are more desirable than others.
Here we describe the results of a QTL analysis performed to study the genetic control of growth traits in apple. This was
carried out on the progeny of a cross between two apple cultivars of contrasting tree architectures. “Telamon” has a columnar
tree form and “Braeburn” has a more standard, “normal” growth habit. The growth traits were measured on the F
1 seedlings of the Telamon × Braeburn population for two consecutive years of growth on own roots and for the first year
of growth on M9 rootstock. QTL analysis was carried out using either the Kruskal–Wallis method or the Multiple QTL Method.
For all but one growth characteristic, significant QTLs were detected. A major cluster of QTLs was located in the Co gene region of “Telamon”, confirming the major influence of the Co gene on tree architecture, although this influence changed as the plant material aged and was generally more pronounced for
rootstock-grown plants. Additional QTL results suggest the occurrence of genes with pleiotropic effects on tree architecture.
The observed QTL instability over different years and for different root systems indicates that the genetic control of tree
architecture is largely influenced by environmental factors and probably changes as the tree matures. Finally, a major influence
of the root system on all the traits determining tree architecture was clearly demonstrated. 相似文献
17.
N. Ahmadi L. Albar G. Pressoir A. Pinel D. Fargette A. Ghesquière 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):1084-1092
Our previous studies have hypothesised that a complementary epistasis between a QTL located on chromosome 12 and a QTL located
on chromosome 7 was one of the major genetic factors controlling partial resistance to Rice yellow mottle virus (RYMV). We report research undertaken to verify this hypothesis and to introgress the resistant allele of these two QTLs
from an upland resistant japonica variety, Azucena, into a lowland susceptible indica variety IR64. Three cycles of molecular marker-assisted back cross breeding were performed using RFLP and microsatellite
markers. Resistance to RYMV was evaluated in F2 and F3 offspring of the BC1 and BC2 generations. Marker-assisted introgression (MAI) was very efficient: in the selected BC3 progeny the proportion of the recipient genome was close to 95% for the ten non-carrier chromosomes, and the length of the
donor chromosome segment surrounding the two QTLs was less than 20 cM. The relevancy of the complementary epistasis genetic
model proposed previously was confirmed experimentally: in BC1 and BC2 generations only F3 lines having the allele of the resistant parent on QTL12 and QTL7 show partial resistance to RYMV. Comparison of our experimental process of MAI with the recommendations of analytic and simulation
studies pointed out the methodological flexibility of MAI. Our results also confirmed the widely admitted, but rarely verified,
assumption that QTL-alleles detected in segregating populations could be treated as units of Mendelian inheritance and that
the incorporation of these alleles into elite lines would result in an enhanced performance. The next step will be the design
of tools for the routine use of molecular markers in breeding for partial resistance to RYMV and the development of material
for the analysis of resistance mechanisms and the structure of a virus resistance gene in rice.
Received: 11 August 2000 / Accepted: 20 March 2001 相似文献
18.
Dormancy release is an important phenological stage, which determines plant growth and survival in northern temperate regions. Spring bud flushing was studied in a Salix pedigree (n=82) derived from a cross between the male hybrid clone "Bj?rn" (Salix viminalis x Salix schwerinii) and the female clone "78183" (Salix viminalis). The timing of bud flush was recorded outdoors in two consecutive years (1998, 1999) and indoor in the spring of 1998. Timing of bud flush was found to be under moderately strong genetic control (clonal mean heritabilities ranging from 0.43 to 0.72). Phenotypic correlations between height growth and bud flushing were negative but non-significant (r=0.1-0.3). Using a Salix linkage map composed of 325 AFLP and 38 RFLP markers, six quantitative trait loci (QTLs) and three unmapped marker loci associated with timing of bud flush were detected. Four QTLs were detected in the field experiment while two QTLs and three unmapped marker loci were identified in the indoor experiment. One QTL associated with indoor bud flushing coincided with one of the QTL detected from the field data. Individual QTL explained 6-16% of the phenotypic variance [corrected]. None of the bud flush QTLs coincided with QTLs controlling height growth identified previously in the same pedigree. 相似文献
19.
20.
Mapping of quantitative trait loci controlling adaptive traits in coastal Douglas-fir. I. Timing of vegetative bud flush 总被引:1,自引:0,他引:1
K. D. Jermstad D. L. Bassoni K. S. Jech N. C. Wheeler D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1142-1151
Thirty three unique quantitative trait loci (QTLs) affecting the timing of spring bud flush have been identified in an intraspecific
mapping population of coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii]. Both terminal and lateral bud flush were measured over a 4-year period on clonal replicates at two test sites, allowing
for the repeated estimation of QTLs. QTLs were detected on 12 linkage groups and, in general, each explained a small proportion
of the total phenotypic variance and were additive in effect. Several QTLs influence the timing of bud flush over multiple
years, supporting earlier evidence that the timing of bud flush through developmental stages is under moderate to strong genetic
control by the same suite of genes through developmental stages. However, only a few QTLs controlling the timing of bud flush
were detected at both test sites, suggesting that geographic location plays a major role in the phenology of spring growth.
A small number of QTLs with year and site interactions were also estimated.
Received: 20 July 2000 / Accepted: 19 October 2000 相似文献