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1.
S. Doganlar J. Dodson B. Gabor T. Beck-Bunn C. Crossman S. D. Tanksley 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(5-6):784-788
We report the molecular mapping of the py-1 gene for resistance to corky root rot [Pyrenochaeta lycopersici (Schneider and Gerlach)] in tomato using RAPD and RFLP marker analysis. DNA from near-isogenic lines (NILs) of tomato differing
in corky root rot resistance was screened with 575 random oligonucleotide primers to detect polymorphic DNAs linked to py-1. Three primers (OPW-04, OPC-02, OPG-19) revealed polymorphisms between the NILs. Twelve resistant and eight susceptible DNA
pools derived from segregating F3 families were used to confirm that the RAPD markers were linked to the py-1 gene. Two of the linked amplified fragments, corresponding to OPW-04 and OPC-02, were subsequently cloned and mapped on the
tomato molecular linkage map as RFLPs. These clones were located between TG40 and CT31 on the short arm of chromosome 3. Further
analysis with selected RFLP markers showed that 7% (8.8 cM) of chromosome 3 of the resistant line ‘Moboglan’ was introgressed
from the L. peruvianum donor parent. Three RFLP markers (TG40, TG324, and TG479) from the introgressed part of chromosome 3 were converted to cleaved
amplified polymorphism (CAP) markers for use in a polymerase chain reaction (PCR) assay. These PCR markers will allow rapid
large-scale screening of tomato populations for corky root rot resistance.
Received: 2 January 1998 / Accepted: 12 January 1998 相似文献
2.
V. Chagué J. C. Mercier M. Guénard A. de Courcel F. Vedel 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(8):1045-1051
Bulked segregant analysis was used to identify random amplified polymorphic DNA (RAPD) markers linked to the Sw-5 gene for resistance to tomato spotted wilt virus (TSWV) in tomato. Using two pools of phenotyped individuals from one segregating population, we identified four RAPD markers linked to the gene of interest. Two of these appeared tightly linked to Sw-5, whereas another, linked in repulsion phase, enabled the identification of heterozygous and susceptible plants. After linkage analysis of an F2 population, the RAPD markers were shown to be linked to Sw-5 within a distance of 10.5 cM. One of the RAPD markers close to Sw-5 was used to develop a SCAR (sequence characterized amplified region) marker. Another RAPD marker was stabilized into a pseudo-SCAR marker by enhancing the specificity of its primer sequence without cloning and sequencing. RAPD markers were mapped to chromosome 9 on the RFLP tomato map developed by Tanksley et al. (1992). The analysis of 13 F3 families and eight BC2 populations segregating for resistance to TSWV confirmed the linkage of the RAPD markers found. These markers are presently being used in marker-assisted plant breeding. 相似文献
3.
Development of RAPD and SCAR markers linked to the Russian wheat aphid resistance gene Dn2 in wheat 总被引:5,自引:0,他引:5
A. A. Myburg M. Cawood B. D. Wingfield A.-M. Botha 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(8):1162-1169
RAPD (random amplified polymorphic DNA) analysis was used to identify molecular markers linked to the Dn2 gene conferring resistance to the Russian wheat aphid (Diuraphis noxia Mordvilko). A set of near-isogenic lines (NILs) was screened with 300 RAPD primers for polymorphisms linked to the Dn2 gene. A total of 2700 RAPD loci were screened for linkage to the resistance locus. Four polymorphic RAPD fragments, two in
coupling phase and two in repulsion phase, were identified as putative RAPD markers for the Dn2 gene. Segregation analysis of these markers in an F2 population segregating for the resistance gene revealed that all four markers were closely linked to the Dn2 locus. Linkage distances ranged from 3.3 cM to 4.4 cM. Southern analysis of the RAPD products using the cloned RAPD markers
as probes confirmed the homology of the RAPD amplification products. The coupling-phase marker OPB10880c and the repulsion-phase marker OPN1400r were converted to sequence characterized amplified region (SCAR) markers. SCAR analysis of the F2 population and other resistant and susceptible South African wheat cultivars corroborated the observed linkage of the RAPD
markers to the Dn2 resistance locus. These markers will be useful for marker-assisted selection of the Dn2 gene for resistance breeding and gene pyramiding.
Received: 1 July 1997 / Accepted: 20 October 1997 相似文献
4.
Genetics of resistance to ascochyta blight (Ascochyta lentis) of lentil and the identification of closely linked RAPD markers 总被引:1,自引:0,他引:1
R. Ford E. C. K. Pang P. W. J. Taylor 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(1):93-98
Foliar resistance to Ascochyta lentis is controlled at a single major locus by a dominant gene (AbR
1
) in the lentil accession ILL5588 (cv ‘Northfield’). Flanking RAPD markers that are closely linked to the resistance locus
in coupling phase were identified by bulked segregant analysis. Out of 261 decanucleotide primers screened 7 produced a polymorphic
marker that segregated with the resistance locus, and all markers were found to exist within a single linkage group. Five
of the seven RAPD markers were within 30 cM of the resistance locus. Log likelihood analysis for detecting QTL associated
with the foliar resistance revealed that a single narrow peak accounted for almost 90% of the variance of resistance between
the bulks. Preliminary mapping in an F3 population revealed that the closest flanking markers were approximately 6 and 14 centiMorgans (cM) away from the resistance
locus. These markers should be useful for the discrimination of resistant germplasm through marker-assisted selection in future
breeding programmes and represent the first essential step towards the map-based cloning of this resistance gene.
Received: 18 December 1997 / Accepted: 9 June 1998 相似文献
5.
Saturation mapping of a major gene for resistance to white pine blister rust in sugar pine 总被引:6,自引:1,他引:5
D. M. Harkins P. A. Skaggs A. D. Mix G. E. Dupper M. E. Devey B. B. Kinloch Jr. D. B. Neale G. N. Johnson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(8):1355-1360
The molecular basis of resistance to diseases in plants can be better understood if the genes coding for resistance can be
cloned. The single major dominant gene (R) that confers resistance to the white pine blister rust fungus (Cronartium ribicola Fisch.) in sugar pine (Pinus lambertiana Dougl.) has been previously mapped. The objectives of the present study were to saturate the region flanking R with tightly
linked markers and to construct genetic maps for each of four individual seed trees. Bulked segregant analysis (BSA) and haploid
segregation analysis were employed to identify random amplified polymorphic DNA (RAPD) markers linked to R. Automated PCR
analysis was used to assay 1115 primers with susceptible and resistant DNA pools from each of four seed trees (8920 PCR reactions).
Thirteen RAPD loci were identified that were linked to R. The linkage analyses programs JoinMap 1.4 and Mapmaker 2.0 were
used to order RAPD loci relative to R and to construct maps for each of the individual seed trees. Two seed trees, 5701 and
6000, had a large number of tightly linked markers flanking R. These trees will be used in subsequent high-resolution mapping
experiments to identify very tightly linked markers to facilitate the eventual cloning of R.
Received: 1 May 1998 / Accepted: 13 July 1998 相似文献
6.
Fuli Liu Jianting Yao Xiuliang Wang Zimin Hu Delin Duan 《Journal of applied phycology》2011,23(4):709-713
To construct a molecular-marker-assisted selection (MAS) system, research was done on identifying molecular markers linking
to longer frond length, a crucial selection index in the breeding of the commercially important seaweed Saccharina japonica. An F2-segregant population of 92 individuals was obtained by crossing two prominent S. japonica strains. Genomic DNA from ten individuals with the longest frond and ten individuals with the shortest frond in the F2-segregant population were mixed to create two DNA pools for screening polymorphic markers. In bulked-segregant analysis (BSA),
out of 100 random amplified polymorphic DNA (RAPD) primers only two produced three polymorphic RAPD markers between the two
DNA pools. In conversion of the three RAPD markers into sequence-characterized amplified region (SCAR) markers, only one was
successfully converted into a SCAR marker FL-569 linking to the trait of longer frond. Test of the marker FL-569 showed that
80% of the individuals with longest fronds in a wild population and 87.5% of individuals with the longest fronds in an inbred
line “Zhongke No. 2” could be detected by FL-569. Additionally, genetic linkage analysis showed that the SCAR marker could
be integrated into the reported genetic map and QTL mapping showed that FL-569 linking to qL1-1. The obtained marker FL-569
will be beneficial to MAS in S. japonica breeding. 相似文献
7.
E. Dirlewanger P. G. Isaac S. Ranade M. Belajouza R. Cousin D. de Vienne 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(1):17-27
An F2 population of pea (Pisum sativum L.) consisting of 174 plants was analysed by restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) techniques. Ascochyta pisi race C resistance, plant height, flowering earliness and number of nodes were measured in order to map the genes responsible for their variation. We have constructed a partial linkage map including 3 morphological character genes, 4 disease resistance genes, 56 RFLP loci, 4 microsatellite loci and 2 RAPD loci. Molecular markers linked to each resistance gene were found: Fusarium wilt (6 cM from Fw), powdery mildew (11 cM from er) and pea common Mosaic virus (15 cM from mo). QTLs (quantitative traits loci) for Ascochyta pisi race C resistance were mapped, with most of the variation explained by only three chromosomal regions. The QTL with the largest effect, on chromosome 4, was also mapped using a qualitative, Mendelian approach. Another QTL displayed a transgressive segregation, i.e. the parental line that was susceptible to Ascochyta blight had a resistance allele at this QTL. Analysis of correlations between developmental traits in terms of QTL effects and positions suggested a common genetic control of the number of nodes and earliness, and a loose relationship between these traits and height. 相似文献
8.
C. Djian-Caporalino L. Pijarowski A. Fazari M. Samson L. Gaveau C. O’Byrne V. Lefebvre C. Caranta A. Palloix P. Abad 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(4):592-600
The PM687 line of Capsicum annuum L. has a single dominant gene, Me
3
, that confers heat-stable resistance to root-knot nematodes (RKN). Me
3
was mapped using doubled-haploid (DH) lines and F2 progeny from a cross between the susceptible cultivar ’Yolo Wonder’ (’YW’) and the highly resistant line ’PM687’. Bulked-segregant
analysis with DNA pools, from susceptible or resistant DH lines, was performed to identify RAPD and AFLP markers linked to
Me
3
. There was no polymorphism between bulks of ten DH lines using over 800 RADP primers (4,000 amplified fragments analysed).
Using 512 AFLP primers (74,000 amplified fragments analysed), and bulked DNA templates from 20 resistant and 20 susceptible
plants, we identified eight repulsion-phase and four coupling-phase markers linked to Me
3.
Analysed in 103 DH progeny, they defined a 56.1-cM interval containing the target gene. The nearest were located 0.5, 1.0,
1.5 and 3.0 centimorgans (cM) on both sides of the gene. Analysis of the F2 progeny (162 plants) with the nearest coupling-phase marker confirmed its close position. Another resistance gene to RKN,
present in ’PM687’ (Me
4
), was shown to be linked to Me
3
, 10 cM from it. In order to localize Me
3
and Me
4
on our reference intraspecific pepper linkage map, two AFLP markers were mapped. The Me
3
nearest marker was 10.1cM from a RAPD marker named Q04_0.3 and 2.7cM from a RFLP marker named CT135. We investigated map-position
orthologies between Me
3
and two other nematode resistance genes, the tomato Mi-3 and the potato Gpa
2
genes, which mapped in the telomeric region of the short arm of the tomato and potato chromosome 12 (or XII for potato).
Received: 23 March 2000 / Accepted: 2 January 2001 相似文献
9.
S. Doganlar S. D. Tanksley M. A. Mutschler 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(2):249-255
Using RAPD marker analysis, two quantitative trait loci (QTLs) associated with earliness due to reduced fruit-ripening time
(days from anthesis to ripening = DTR) were identified and mapped in an F2 population derived from a cross between Lycopersicon esculentum’E6203’ (normal ripening) and Lycopersicon esculentum’Early Cherry’ (early ripening). One QTL, on chromosome 5, was associated with a reduction in both ripening time (5 days)
and fruit weight (29.3%) and explained 15.8 and 13% of the total phenotypic variation for DTR and fruit weight, respectively.
The other QTL, on chromosome 12, was primarily associated with a reduction only in ripening time (7 days) and explained 12.3%
of the total phenotypic variation for DTR. The gene action at this QTL was found to be partially dominant (d/a=0.41). Together,
these two QTLs explained 25.1% of the total phenotypic variation for DTR. Additionally, two QTLs associated with fruit weight
were identified in the same F2 population and mapped to chromosomes 4 and 6, respectively. Together, these two QTLs explained 30.9% of the total phenotypc
variation for fruit weight. For all QTLs, the ’Early Cherry’ alleles caused reductions in both ripening time and fruit weight.
The polymorphic band for the most significant RAPD marker (OPAB-06), linked to the reduced ripening time QTL on chromosome
12, was converted to a cleaved amplified polymorphism (CAP) assay for marker-aided selection and further introgression of
early ripening time (DTR) into cultivated tomato.
Received: 15 March 1999 / Accepted: 29 April 1999 相似文献
10.
S. K. Naess J. M. Bradeen S. M. Wielgus G. T. Haberlach J. M. McGrath J. P. Helgeson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):697-704
Somatic hybrids between potato and Solanum bulbocastanum, a wild diploid (2n=2x=24) Mexican species, are highly resistant to late blight, caused by Phytophthora infestans. Both randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers that are closely
linked to the resistance have been noted by analysis of three different backcross-2 populations derived from two different
somatic hybrids. With reference to previously published potato and tomato maps, resistance appears to be on the long arm of
chromosome 8 and is flanked by RFLP markers CP53 and CT64. In a population of BC2 plants derived from a cross between the BC1 line J10lK6 [(S. tuberosum PI 203900+S. bulbocastanum PI 243510) ×Katahdin)]×Atlantic, late blight resistance cosegregated with RFLP marker CT88 and RAPD marker OPG02–625.
Received: 26 November 1999 / Accepted: 22 December 1999 相似文献
11.
R. N. Morgan J. P. Wilson W. W. Hanna P. Ozias-Akins 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(3-4):413-420
Pearl millet [Pennisetum glaucum (L.) R.Br.] is a warm-season grass used for food, feed, fodder and forage, primarily in countries of Africa and India but
grown around the world. The two most-destructive diseases to pearl millet in the United States are rust (caused by Puccinia substriata var. indica) and pyricularia leaf spot (caused by Pyricularia grisea). Genes for disease resistance to both pathogens have been transferred into agronomically acceptable forage and grain cultivars.
A study was undertaken to identify molecular markers for three rust loci and one pyricularia resistance locus. Three segregating
populations were screened for RAPDs using random decamer primers and for RFLPs using a core set of probes detecting single-copy
markers on the pearl millet map. The rust resistance gene Rr
1
from the pearl millet subspecies P. glaucum ssp. monodii was linked 8.5 cM from the RAPD OP-G8350. The linkage of two RFLP markers, Xpsm108 (15.5 cM) and Xpsm174 (17.7 cM), placed the Rr
1
gene on linkage-group 3 of the pearl millet map. Rust resistance genes from both Tift 89D2 and ICMP 83506 were placed on linkage-group 4 by determining genetic linkage to the RFLP marker Xpsm716 (4.9 and 0.0 cM, respectively). Resistance in ICMP 83506 was also linked to the RFLP marker Xpsm306 (10.0 cM), while resistance in Tift 89D2 was linked to RAPD markers OP-K19350 (8.8 cM) and OP-O8350 (19.6 cM). Fragments from OP-K19 and OP-O8 in the ICMP 83506 population, and Xpsm306 in the Tift 89D2 population, were monomorphic. Only one RAPD marker (OP-D11700, 5.6 cM) was linked to pyricularia leaf spot resistance. Attempts to detect polymorphisms with rice RFLP probes linked to
rice blast resistance (Pyricularia oryzae; syn=P. grisea) were unsuccessful.
Received: 19 May 1997 / Accepted: 21 October 1997 相似文献
12.
Identification of RAPD markers linked to a Phytophthora fragariae resistance gene (Rpf1) in the cultivated strawberry 总被引:2,自引:0,他引:2
K. M. Haymes B. Henken T. M. Davis W. E. van de Weg 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(8):1097-1101
Bulked segregant analysis (BSA) was used to identify seven random amplified polymorphic DNA (RAPD) markers linked to the
Rpf 1 gene. Rpf 1 confers resistance to Phytophthora fragariae var. fragariae, the causal agent of red stele root rot in Fragaria spp. The bulked DNAs represented subsets of a F1 population obtained from the cross Md683×Senga Sengana which consisted of 60 plants and segregated in a 1:1 ratio for resistance
or susceptibility to race 2.3.4 isolate NS2 of P. fragariae. Seven markers were shown to be linked to Rpf 1 and were generated from four primers; five of these markers were in coupling phase and two in repulsion phase with respect
to the gene. A linkage map of this resistance gene region was generated using JoinMap 2.0TM. The manner in which Rpf 1 and the linked markers co-segregated indicated that they are inherited in a disomic fashion. These markers could enable gene
pyramiding and marker-assisted selection of resistance genes in strawberry breeding programmes.
Received: 26 August 1996 / Accepted: 20 December 1996 相似文献
13.
M. R. Stevens E. M. Lamb D. D. Rhoads 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,90(3-4):451-456
The Sw-5 locus confers dominant resistance to tomato spotted wilt virus (TSWV). To map the location and facilitate the identification of markers linked to Sw-5 we developed a pair of near-isogenic lines (NILs) and an F2
Lycopersicon esculentum x L. pennellii population segregating for resistance to TSWV. DNA from the NILs was analyzed using 748 random 10-mer oligonucleotides to discern linked molecular markers using a random amplified polymorphic DNA (RAPD) approach. One random primer (GAGCACGGGA) was found to produce a RAPD band of about 2200 bp that demonstrates linkage to Sw-5. Data from co-segregation of resistance and restriction fragment length polymorphisms (RFLPs) in a F2 interspecific population position Sw-5 between the markers CT71 and CT220 near the telomere of the long arm of chromosome 9. 相似文献
14.
Murat Akkurt Leocir Welter Erika Maul Reinhard Töpfer Eva Zyprian 《Molecular breeding : new strategies in plant improvement》2007,19(2):103-111
Sequence-characterized amplified regions markers (SCARs) were developed from six randomly amplified polymorphic DNA (RAPD)
markers linked to the major QTL region for powdery mildew (Uncinula necator) resistance in a test population derived from the cross of grapevine cultivars “Regent” (resistant) × “Lemberger”(susceptible).
RAPD products were cloned and sequenced. Primer pairs with at least 21 nucleotides primer length were designed. All pairs
were tested in the F1 progeny of “Regent” × “Lemberger”. The SCAR primers resulted in the amplification of specific bands
of expected sizes and were tested in additional genetic resources of resistant and susceptible germplasm. All SCAR primer
pairs resulted in the amplification of specific fragments. Two of the SCAR markers named ScORA7-760 and ScORN3-R produced
amplification products predominantly in resistant individuals and were found to correlate to disease resistance. ScORA7-760,
in particular, is suitable for marker-assisted selection for powdery mildew resistance and to facilitate pyramiding powdery
mildew resistance genes from various sources. 相似文献
15.
Identification of molecular markers linked to quantitative trait loci for soybean resistance to corn earworm 总被引:7,自引:0,他引:7
B. G. Rector J. N. All W. A. Parrott H. R. Boerma 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):786-790
One hundred and thirty nine restriction fragment length polymorphisms (RFLPs) were used to construct a soybean (Glycine max L. Merr.) genetic linkage map and to identify quantitative trait loci (QTLs) associated with resistance to corn earworm (Helicoverpa zea Boddie) in a population of 103 F2-derived lines from a cross of ‘Cobb’ (susceptible) and PI229358 (resistant). The genetic linkage map consisted of 128 markers
which converged onto 30 linkage groups covering approximately 1325 cM. There were 11 unlinked markers. The F2-derived lines and the two parents were grown in the field under a plastic mesh cage near Athens, Ga., in 1995. The plants
were artificially infested with corn earworm and evaluated for the amount of defoliation. Using interval-mapping analysis
for linked markers and single-factor analysis of variance (ANOVA), markers were tested for an association with resistance.
One major and two minor QTLs for resistance were identified in this population. The PI229358 allele contributed insect resistance
at all three QTLs. The major QTL is linked to the RFLP marker A584 on linkage group (LG) ‘M’ of the USDA/Iowa State University
public soybean genetic map. It accounts for 37% of the total variation for resistance in this cross. The minor QTLs are linked
to the RFLP markers R249 (LG ‘H’) and Bng047 (LG ‘D1’). These markers explain 16% and 10% of variation, respectively. The
heritability (h2) for resistance was estimated as 64% in this population.
Received: 15 October 1997 / Accepted: 4 November 1997 相似文献
16.
RFLP and RAPD markers linked to the rosy leaf curling aphid resistance gene (Sd1) in apple 总被引:10,自引:0,他引:10
P. Roche F. H. Alston C. Maliepaard K. M. Evans R. Vrielink F. Dunemann T. Markussen S. Tartarini L. M. Brown C. Ryder G. J. King 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):528-533
Sd
1 is a dominant gene for resistance to biotypes 1 and 2 of the rosy leaf curling aphid, Dysaphis devecta Wlk., which can cause economic damage to apple trees. This report describes the identification of three RFLP and four RAPD
markers linked to Sd
1 in a cross between the D. devecta susceptible variety ‘Prima’ (sd
1
sd
1) and the resistant variety ‘Fiesta’ (Sd
1
sd
1). Potted trees were artificially infested in the glasshouse, and the ratio of resistant:susceptible plants supported the
hypothesis that the resistance was under the control of a single dominant gene. The position of the gene was mapped to a single
locus on a ‘Fiesta’ chromosome, within 2 cM of three tightly linked RFLP markers (MC064a, 2B12a and MC029b); the four RAPD
markers were located further away (between 13 and 46 cM). This is the first report of molecular markers for an aphid resistance
gene in tree fruit crops. The potential application of these markers in a marker-assisted resistance breeding programme is
discussed.
Received: 1 July 1996/Accepted: 23 August 1996 相似文献
17.
Kassem My.A. Meksem K. Kang C.H. Njiti V.N. Kilo V. Wood A.J. Lightfoot D.A. 《Plant and Soil》2004,260(1-2):197-204
Resistance to manganese toxicity is associated with some soybean (Glycine max) cultivars grown on acidic soils or in hydroponics. Previously random amplified polymorphic DNA (RAPD) markers had seemed to identify 4 quantitative trait loci (QTL), regions that might underlie resistance to manganese toxicity in a recombinant inbred line (RIL) population derived from ‘Essex’ x ‘Forrest’. Our objective was to identify microsatellite markers linked to these, or additional, QTL for resistance to manganese toxicity in a separate assay. Two hundred and forty microsatellite markers and 100 RILs were used to construct a map. The response of five plants per genotype to manganese was measured by leaf chlorosis (scored from 0–5) and root necrosis (scored from 0–5) from 7–28 days after treatment with 125 μM of manganese in hydroponics. The experiment was repeated. ANOVA and MapMaker/QTL were used to identify regions underlying the responses. Three genomic regions on different linkage groups were found to contain QTL for resistance to necrosis during manganese toxicity. The regions located on linkage groups C2 (BARC_S att291),I(BARC_S att239)andG(OP_O EO2)wereeachsignificantlyassociated(P<0.005, R 2=20%) with root necrosis at 7 days after treatment. The regions all derived the beneficial allele from Essex. One of the previously identified RAPD associated root necrosis QTL was identified in this new study. However, no QTL for leaf chlorosis were detected (P<0.005) and none of the RAPD identified leaf chlorosis QTL could be identified. We conclude that root and leaf resistance to manganese toxicity are environmentally sensitive quantitative traits determined by separate loci of different number and magnitude of effect. 相似文献
18.
Quantitative trait loci (QTL) have been identified for competence of the mosquito Aedes aegypti to transmit the avian malaria parasite Plasmodium gallinaceum and the human filarial parasite Brugia malayi. Efforts towards the map-based cloning of the associated genes are limited by the availability of genetic markers for fine-scale mapping of the QTL positions. Two F2 mosquito populations were subjected to bulked segregant analysis to identify random amplified polymorphic DNA (RAPD)-PCR fragments linked with the major QTL determining susceptibility to both parasites. Individual mosquitoes for the bulks were selected on the basis of their genotypes at restriction fragment length polymorphism (RFLP) loci tightly linked with the QTL. Pool-positive RAPD fragments were cloned and evaluated as RFLP markers. Of the 62 RAPD/RFLP fragments examined, 10 represented low-copy number sequences. Five of these clones were linked with the major QTL for P. gallinaceum susceptibility (pgs1), of which one clone mapped within the flanking markers that define the QTL interval. The remaining five clones were linked with the major QTL for B. malayi susceptibility (fsb1), and again one clone mapped within the flanking markers that define the QTL interval. In addition, nine RAPD/RFLP fragments were isolated that seem to be of non-mosquito origin. 相似文献
19.
This study was conducted to identify randomly amplified polymorphic DNA (RAPD) markers associated with quantitative trait
loci (QTLs) conferring salt tolerance during germination in tomato. Germination response of an F2 population (2000 individuals) of a cross between UCT5 (Lycopersicon esculentum, salt-sensitive) and LA716 (L. pennellii, salt-tolerant) was evaluated at a salt-stress level of 175 mM NaCl+17.5 mM CaCl2 (water potential ca. –9.5 bars). Germination was scored visually as radicle protrusion at 6-h intervals for 30 consecutive
days. Individuals at both extremes of the response distribution (i.e., salt-tolerants and salt-sensitives) were selected.
The selected individuals were genotyped for 53 RAPD markers and allele frequencies at each marker locus were determined. The
linkage association among the markers was determined using a “Mapmaker” program. Trait-based marker analysis (TBA) identified 13 RAPD markers at eight genomic regions that were associated with
QTLs affecting salt tolerance during germination in tomato. Of these genomic regions, five included favorable QTL alleles
from LA716, and three included favorable alleles from UCT5. The approximate effects of individual QTLs ranged from 0.46 to
0.82 phenotypic standard deviation. The results support our previous suggestion that salt tolerance during germination in
tomato is polygenically controlled. The identification of favorable QTLs in both parents suggests the likelihood of recovering
transgressive segregants in progeny derived from these genotypes. Results from this study are discussed in relation to using
marker-assisted selection in breeding for salt tolerance.
Received: 16 June 1997 / Revision received: 11 August 1997 / Accepted: 2 September 1997 相似文献
20.
Naweed I. Naqvi J. Michael Bonman David J. Mackill Rebecca J. Nelson Bharat B. Chattoo 《Molecular breeding : new strategies in plant improvement》1995,1(4):341-348
Rice blast, caused byPyricularia grisea, is a major production constraint in many parts of the world. The Korean rice variety Tongil showed high levels of resistance for about six years when widely planted under highly disease-conducive conditions, before becoming susceptible. Tongil was found to carry a single dominant gene, designatedPi-10t, conferring resistance to isolate 106 of the blast pathogen from the Philippines. We report here the use of bulked segregant RAPD analysis for rapid identification of DNA markers linked toPi-10t. Pooled DNA extracts from five homozygous blast-resistant (RR) and five susceptible (rr) BC3F2 plants, derived from a CO39 × Tongil cross, were analyzed by RFLP using 83 polymorphic probes and by RAPD using 468 random oligomers. We identified two RAPD markers linked to thePi-10t locus: RRF6 (3.8 ± 1.2 cM) and RRH18 (2.9 ± 0.9 cM). Linkage of these markers withPi-10t was verified using an F2 population segregating forPi-10t. The two linked RAPD markers mapped 7 cM apart on chromosome 5. Chromosomal regions surrounding thePi-10t gene were examined with additional RFLP markers to define the segment introgressed from the donor genome.Pi-10t is likely to be a new blast-resistance locus, because no other known resistance gene has been mapped on chromosome 5. These tightly linked RAPD markers could facilitate early selection of thePi-10t locus in rice breeding programmes. 相似文献