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1.
Aegilops longissima Schw. et Musch. (2n= 2x=14, SlSl) and Aegilops sharonensis Eig. (2n=2x=14, SlSl) are diploid species belonging to the section Sitopsis in the tribe Triticeae and potential donors of useful genes for wheat breeding. A comparative genetic map was constructed of the Ae. longissima genome, using RFLP probes with known location in wheat. A high degree of conserved colinearity was observed between the wild diploid and basic wheat genome, represented by the D genome of cultivated wheat. Chromosomes 1Sl, 2Sl, 3Sl, 5Sl and 6Sl are colinear with wheat chromosomes 1D, 2D, 3D, 5D and 6D, respectively. The analysis confirmed that chromosomes 4Sl and 7Sl are translocated relative to wheat. The short arms and major part of the long arms are homoeologous to most of wheat chromosomes 4D and 7D respectively, but the region corresponding to the distal segment of 7D was translocated from 7SlL to the distal region of 4SlL. The map and RFLP markers were then used to analyse the genomes and added chromosomes in a set of ’Chinese Spring’ (CS)/Ae. longissima chromosome additions. The study confirmed the availability of disomic CS/Ae. longissima addition lines for chromosomes 1Sl, 2Sl, 3Sl, 4Sl and 5Sl. An as yet unpublished set of Ae. sharonensis chromosome addition lines were also available for analysis. Due to the gametocidal nature of Ae. sharonensis chromosomes 2Sl and 4Sl, additions 1Sl, 3Sl, 5Sl, 6Sl and 7Sl were produced in a (4D)4Sl background, and 2Sl and 4Sl in a euploid wheat background. The analysis also confirmed that the 4/7 translocation found in Ae. longissima was not present in Ae. sharonensis although the two wild relatives of wheat are considered to be closely related. The phenotypes of the Ae. sharonensis addition lines are described in an Appendix. Received: 28 September 2000 / Accepted: 19 January 2001  相似文献   

2.
3.
The amount of alien chromatin introgressed in eight wheat/Ae. longissima Pm13 recombinant lines, involving breakpoints on the short arms of wheat chromosomes 3B and 3D, was evaluated by cytogenetic and molecular approaches. For each line the residual homologous synaptic ability of the recombinant chromosome in its proximal wheat and distal alien portion was estimated through meiotic analyses. Subsequently, telocentric and RFLP mapping were used to assess the genetic distance from the wheat centromere to the wheat/Ae. longissima breakpoints. One 3B recombinant line was distinguished from the other four by the chromosome pairing and telocentric mapping analyses. RFLP analysis succeeded in differentiating the remaining four lines into two groups. Chromosome pairing and telocentric mapping of the three 3D recombinant lines suggested that all had distinct breakpoints. However, the RFLP data could not discriminate between the two more proximal translocations. Physical locations for some RFLP loci were determined by a comparison of genotypes and C-banding karyotypes. This showed a considerable expansion of the genetic map compared to its physical length.  相似文献   

4.
 The potential of PCR-based markers for construction of a genetic linkage map in Einkorn wheat was investigated. From a comparison of polymorphisms between two Einkorn wheats, Triticum monococcum (Mn) and T. boeoticum (Bt), we obtained 49 polymorphic bands produced by 33 primers for inter-simple sequence repeat (ISSR) and 36 polymorphic bands shown by 25 combinations of random amplified polymorphic DNA (RAPD) primers for mapping in 66 individuals in the F2 population. Although 44 ISSR fragments and 29 RAPD fragments statistically showed a 3 : 1 segregation ratio in the F2 population, only 9 markers each of the ISSR and RAPD bands were able to be mapped on the RFLP linkage map of Einkorn wheat. ISSR markers were distributed throughout the chromosomes. The mapped positions of the ISSR markers seemed to be similar to those obtained by the RFLP markers. On the other hand, 4 of the 9 RAPD markers could map the RFLP marker-poor region on the short arm of 3Am, suggesting a potential to map novel regions containing repetitive sequences. Comparisons of the genetic linkage map of Einkorn wheat to the linkage map and cytological map of common wheat revealed that the marker orders between the two maps of Einkorn wheat and common wheat coincided except for 4A, which harbors chromosome rearrangements specific for polyploid wheats, indicating a conservatism between the two genomes. Recombinations in Einkorn wheat chromosomes took place more frequently around the centromere and less at the distal part of chromosomes in comparison to those in common wheat. Nevertheless, recombinations even in Einkorn wheat chromosomes were strongly suppressed around the centromere. In fact, the markers located within 1 cM of the centromere were located almost in the central part of the chromosome arm. Received: 7 June 1997 / Accepted: 17 June 1997  相似文献   

5.
The use of random amplified polymorphic DNA markers in wheat   总被引:43,自引:0,他引:43  
Summary An evaluation was made of the use of random amplified polymorphic DNA (RAPD) as a genetic marker system in wheat. Reproducible amplification products were obtained from varietal, homozygous single chromosome recombinant line and wheat/alien addition line genomic DNA with selected primers and rigorously optimized reaction conditions. Factors influencing the RAPD patterns are DNA concentration, Mg2+ concentration, polymerase concentration and denaturing temperature. In wheat, the non-homoeologous, non-dose responsive and dominant behaviour of RAPD products devalues their use as genetic markers for the construction of linkage maps, and the high probability that the amplified fragments derive from repetitive DNA limits their use as a source of conventional RFLP probes. However, RAPD markers will most certainly find many applications in the analysis of genotypes where single chromosomes or chromosome segments are to be manipulated.  相似文献   

6.
 RAPD markers were developed for octoploid×Tritordeum (amphiploid Hordeum chilense×Triticum aestivum) and its parents. Addition lines were used to identify specific RAPD markers for the Hordeum chilense chromosomes detectable in a wheat background. Twelve RAPD fragments have been cloned, sequenced and converted into STS markers. Eleven of these STSs have maintained both the chromosome specificity and the possibility of detection in a wheat background. The use of these markers in multiplexed PCRs facilitates both the efficient and reliable screening of new addition lines as well as the monitoring of introgression of H. chilense in bread and durum wheat. Received: 5 June 1998 / Accepted: 17 September 1998  相似文献   

7.
A beet cyst nematode (BCN)-resistant telosomic addition of B. patellaris chromosome 1 in B. vulgaris was used to isolate 6 RAPD markers linked to the BCN resistance locus Hs1 pat-1. Southern analysis showed that the analyzed RAPD products contain either low-, middle or high-repetitive DNA. The relative positions of the random amplified polymorphic DNA (RAPD) markers and of the restriction fragment length polymorphism (RFLP) loci corresponding to the low-repetitive RAPD products were determined by deletion mapping using a panel of seven nematode-resistant B. patellaris chromosome-1 fragment additions. One RAPD marker, OPB11800, was found to be present in two copies on the long arm telosome of B. patellaris chromosome 1. These copies are closely linked to the BCN resistance gene and flank the gene on both sides. On the basis of the nucleotide sequence of OPB11800, sequence-tagged site (STS) primers were developed that amplify specific fragments derived from the two OPB11800 loci. These STS markers can be used in the map-based cloning of the BCN gene, as they define start and finishing points of a chromosomal walk towards the Hs1 pat-1 locus. Two copies of the middle-repetitive OPX21100 marker were mapped in the same interval of the deletion mapping panel as the resistance gene locus and thereby belong to the nearest markers as yet found for the BCN gene in B. patellaris.  相似文献   

8.
 A sequence-tagged-site (STS) marker is reported linked to Lr28, a leaf rust resistance gene in wheat. RAPD (random amplified polymorphic DNA) analysis of near-isogenic lines (NILs) of Lr28 in eight varietal backgrounds was carried out using random primers. Genomic DNA enriched for low-copy sequences was used for RAPD analysis to overcome the lack of reproducibility due to the highly repetitive DNA sequences present in wheat. Of 80 random primers tested on the enriched DNA, one RAPD marker distinguished the NILs and the donor parent from the susceptible recurrent parents. The additional band present in resistant lines was cloned, sequenced, and STS primers specific for Lr28 were designed. The STS marker (Indian patent pending: 380 Del98) was further confirmed by bulk segregation analysis of F3 families. It was consistently present in the NILs, the resistant F3 bulk and the resistant F3 lines, but was absent in recurrent parents, the susceptible F3 bulk and the susceptible F3 lines. Received: 20 February 1998 / Accepted: 4 March 1998  相似文献   

9.
Mapping resistance genes for Oculimacula acuformis in Aegilops longissima   总被引:1,自引:0,他引:1  

Key message

This study identified three QTL conferring resistance to Oculimacula acuformis in Aegilops longissima and their associated markers, which can be useful in marker-assisted selection breeding for eyespot resistance.

Abstract

Oculimacula acuformis is one of two species of soilborne fungi that cause eyespot of wheat, the other being Oculimacula yallundae. Both pathogens can coexist in the same field and produce elliptical lesions on stem bases of wheat that are indistinguishable. Pch1 and Pch2 are the only two eyespot resistance genes readily available to wheat breeders, but neither provides complete control. A new source of eyespot resistance was identified from Aegilops longissima (2n = 14, SlSl), a wild relative of wheat. Three QTL for resistance to O. acuformis were mapped in chromosomes 1Sl, 3Sl, and 5Sl using a recombinant inbred line population developed from the cross Ae. longissima accessions PI 542196 (R) × PI 330486 (S). The three QTL explained 66 % of phenotypic variation by β-glucuronidase score (GUS) and 84 % by visual rating. These QTL had LOD values of 10.6, 8.8, and 6.0 for GUS score, and 16.0, 10.0, and 13.0 for visual rating. QTL associated with resistance to O. acuformis have similar chromosomal locations as some for resistance to O. yallundae, except that a QTL for resistance to O. yallundae was found in chromosome 7Sl but not for O. acuformis. Thus, it appears that some genes at the same locus in Ae. longissima may control resistance to both eyespot pathogens. QTL effective against both pathogens will be most useful for breeding programs and have potential to improve the effectiveness and genetic diversity of eyespot resistance.  相似文献   

10.
Restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers are being used widely for evaluating genetic relationships of crop germplasm. Differences in the properties of these two markers could result in different estimates of genetic relationships among some accessions. Nuclear RFLP markers detected by genomic DNA and cDNA clones and RAPD markers were compared for evaluating genetic relationships among 18 accessions from six cultivated Brassica species and one accession from Raphanus sativus. Based on comparisons of genetic-similarity matrices and cophenetic values, RAPD markers were very similar to RFLP markers for estimating intraspecific genetic relationships; however, the two marker types gave different results for interspecific genetic relationships. The presence of amplified mitochondrial and chloroplast DNA fragments in the RAPD data set did not appear to account for differences in RAPD- and RFLP-based dendrograms. However, hybridization tests of RAPD fragments with similar molecular weights demonstrated that some fragments, scored as identical, were not homologous. In all these cases, the differences occurred at the interspecific level. Our results suggest that RAPD data may be less reliable than RFLP data when estimating genetic relationships of accessions from more than one species.  相似文献   

11.
The first genetic map of the wild South Ameri- can barley species Hordeum chilense is presented. The map, based on an F2 population of 114 plants, contains 123 markers, including 82 RAPDs, 13 SSRs, 16 RFLPs, four SCARs, two seed storage proteins and two STS markers. The map spans 694 cM with an average distance of 5.7 cM between markers. Six additional SSRs and seven additional SCARs which were not polymorphic were assigned to chromosomes using wheat/H. chilense addition lines. Polymorphisms were revealed by 50% of the RAPD amplifications, 13% of wheat and barley SSR primers, and 78% of the Gramineae RFLP anchor probes. The utility of SSR and RFLP probes from other Gramineae species shows the usefulness of a comparative approach as a source of markers and for aligning the genetic map of H. chilense with other species. This also indicates that the overall structure of the H. chilense linkage groups is probably similar to that of the B and D genomes of wheat and the H genome of barley. Applications of the map for tritordeum and wheat breeding are discussed. Received: 20 August 2000 / Accepted: 22 September 2000  相似文献   

12.
Using RFLP analysis with three probes homologous to specific regions of mitochondrial DNA genes and PCR analysis of the mitochondrial recombining-repeat-sequence 18S/5S region of cereals, five alloplasmic wheat lines of different origin and fertility expression were studied. These lines are self-pollinated progeny of BC1-BC4 generations of barley–wheat hybrids Hordeum geniculatum All. (2n = 28) × Triticum aestivum L. (2n = 42). It was found that recombinant alloplasmic lines characterized by partial fertility contain either maternal (barley) DNA fragments or maternal and paternal (wheat) DNA fragments simultaneously (heteroplasmy). In lines with stable expression of self-fertility, fragments of only paternal mitochondrial DNA were detected. It is assumed that in alloplasmic lines, there is the interrelation between the presence of definite fragments of the mitochondrial genome belonging to either parental type and fertility expression.Translated from Genetika, Vol. 41, No. 3, 2005, pp. 349–355.Original Russian Text Copyright © 2005 by Trubacheeva, Salina, Pershina.  相似文献   

13.
Hessian fly is one of the world's most destructive insect pests of wheat Triticum aestivum L. We have used the combination of near-isogenic lines (NIL) and random amplified polymorphic DNA (RAPD) analysis to screen up to 2,000 primers to identify DNA markers that are linked to gene H6 that confers resistance to biotype B of the insect. This screen produced six primers that show polymorphic fragments associated with resistance by H6. We have screened 440 F2 individuals from a cross of the susceptible cultivar Newton and a NIL that contains H6 to verify the linkage between these markers and the resistance gene. A high-resolution genetic map was constructed based on recombination frequency. Two of the markers were tightly linked to the gene with no recombination observed, three were within 2.0 cM, and one was 11 cM from the gene. Three of the six markers were successfully converted to sequence tagged site (STS) markers. Both RAPD and STS primers were used to screen for the presence or absence of the resistance gene in wheat varieties. The identification of markers and construction of the genetic high resolution map provide the first steps toward localization of this resistance gene.  相似文献   

14.
 Seventy nine microsatellite markers from hexaploid bread wheat (T. aestivum L.) were integrated into a genetic linkage map of durum wheat (T. turgidum ssp. durum (Desf.) Huns.) created by RFLP segregation data from a population of 65 recombinant inbred lines. The results indicate a relatively even distribution of microsatellite loci and demonstrate that microsatellite markers from hexaploid wheat provide an excellent source of molecular markers for use in the genetics and breeding of durum wheat. Received: 16 July 1998 / Accepted: 13 October 1998  相似文献   

15.
RFLP markers for the wheat powdery mildew resistance genes Pm1 and Pm2 were tagged by means of near-isogenic lines. The probe Whs178 is located 3 cM from the Pm1 gene. For the powdery mildew resistance gene Pm2, two markers were identified. The linkage between the Pm2 resistance locus and one of these two probes was estimated to be 3 cM with a F2 population. Both markers can be used to detect the presence of the corresponding resistance gene in commercial cultivars. Bulked segregant analysis was applied to identify linkage disequillibrium between the resistance gene Pm18 and the abovementioned marker, which was linked to this locus at a distance of 4 cM. Furthermore, the RAPD marker OPH-111900 (5-CTTCCGCAGT-3) was selected with pools created from a population segregating for the resistance of Trigo BR 34. The RAPD marker was mapped about 13 cM from this resistance locus.  相似文献   

16.
Homoeologous pairing at meiotic metaphase I was analyzed in T. longissimum x T. aestivum hybrids in order to reconfirm the homoeologous relationships of T. longissimum chromosomes to wheat. Hybrids between T. longissimum and Chinese Spring carrying the Ph1 gene or theph1b mutation, which showed low and high pairing levels, respectively, were used. Chromosome arms associated at metaphase I were identified by C-banding. The homoeology of chromosomes 1S l , 2S l , 3S l , 5S l and 6S l to wheat group 1,2, 3, 5, and 6 chromosomes, respectively, was confirmed. Chromsome arms 4S l S and 7S l S showed normal homoeologous relationships to wheat. The 4S l L arm carries a translocated segment from 7S l L relative to wheat. The 7S l L arm seldom paired, likely because this arm lost a relatively long segment and received a very short segment in the interchange with 4S l L. Available data suggest that translocation 4S l L/7S l L arose in the evolution of T. longissimum, which implies that this species was not the donor of the B genome of wheat.  相似文献   

17.
Powdery mildew is a severe foliar disease for wheat and could cause great yield loss in epidemic years. To explore new powdery mildew resistance genes, two einkorn accessions including TA2033 and M80, both resistant to this disease, were studied for the inheritance of resistance. Each accession possessed a single but different dominant resistance gene that was designated as Mlm2033 and Mlm80, respectively. Marker mapping indicated that they are both linked to Xgwm344 on the long arm of chromosome 7A. To establish their genetic relationship with Pm1 on 7AL, five RFLP markers previously reported to co-segregate with Pm1a were converted to STS markers. Three of them detected polymorphism between the mapping parents and were mapped close to Mlm2033 or Mlm80 or both. Xmag2185, the locus determined by the STS marker derived from PSR680, one of the RFLP markers, was placed less than 2 cM away from them. The allelism test indicated that Mlm2033 and Mlm80 are likely allelic to each other. In addition, through comparative and EST mapping, more markers linked to these two genes were identified. The high density mapping of Mlm2033 and Mlm80 will contribute to map-based cloning of the Pm1 locus. The markers for both genes will also facilitate their transfer to wheat.  相似文献   

18.
The RFLP and AFLP techniques are laborious and expensive and therefore of limited use for marker-assisted selection, demanding a high throughput of samples in a short time. But marker-assisted selection is most useful for traits which are hard to score on single plants and influenced by environmental factors. Four RFLP and three AFLP markers have been found to be linked to genes of the B-genome of Brassica mediating resistance against Phoma lingam in oilseed rape. One RFLP and one AFLP marker were converted into three PCR-based STS markers: one of dominant, as well as one of codominant inheritance separated in a standard agarose gel and a third one of codominant inheritance to be separated in a polyacrylamide gel on an automated sequencer. As expected, the STS markers mapped at the same position as the original RFLP and AFLP markers. The STS markers are efficient in marker-assisted backcross programs of the resistant B-genome/Brassica napus recombinant lines with most of the tested oilseed rape varieties and breeding lines. More than 90% of the tested oilseed rape varieties and breeding lines exhibited no resistance marker alleles. The mapping results obtained with the markers, as well as comparative sequencing of the marker alleles, indicate synteny and homology between the B-genome resistance gene donors and B. napus in the region of the resistance genes. The location of the resistance genes in the B-genome/B. napus recombinant lines is most likely on the A genome. Thus the transfer of the B-genome resistance genes into Brassica campestris is also possible. Received: 9 December 1999 / Accepted: 21 June 2000  相似文献   

19.
Powdery mildew is one of the most destructive foliar diseases of wheat. A set of differential Blumeria graminis f.sp. tritici (Bgt) isolates was used to test the powdery mildew response of a Triticum monococcum-derived resistant hexaploid line, Tm27d2. Segregation analysis of 95 F2:3 lines from a Chinese Spring/Tm27d2 cross revealed that the resistance of Tm27d2 is controlled by a single dominant gene. Using monosomic analysis and a molecular mapping approach, the resistance gene was localized to the terminal end of chromosome 2AL. The linkage map of chromosome 2AL consisted of nine simple sequence repeat markers and one sequence-tagged site (STS) marker (ResPm4) indicative for the Pm4 locus. According to the differential reactions of 19 wheat cultivars/lines with known powdery mildew resistance genes to 13 Bgt isolates, Tm27d2 carried a new resistance specificity. The complete association of the resistance allele with STS marker ResPm4 indicated that it represented a new allele at the Pm4 locus. This new allele was designated Pm4d. The two flanking markers Xgwm526 and Xbarc122 closely linked to Pm4d at genetic distances of 3.4 and 1.0 cM, respectively, are present in chromosome bin 2AL1-0.85-1.00.  相似文献   

20.
Near-isogenic lines (NILs) for the leaf rust resistance gene Lr9 were screened for polymorphisms at the molecular level. RAPD (random amplified polymorphic DNA) primers as well as RFLP (restriction fragment length polymorphism) markers were used. Out of 395 RAPD primers tested, three showed polymorphisms between NILs, i.e., an additional band was found in resistant lines. One of these polymorphic bands was cloned and sequenced. Specific primers were synthesized, and after amplification only resistant lines showed an amplified product. Thus, these primers define a sequence-tagged site that is specific for the translocated fragment carrying the Lr9 gene. A cross between a resistant NIL and the spelt (Triticum spelta) variety Oberkulmer was made, and F2 plants were analyzed for genetic linkage. All three polymorphisms detected by the PCR (polymerase chain reaction) and one RFLP marker (cMWG684) showed complete linkage to the Lr9 gene in 156 and 133 plants analyzed, respectively. A second RFLP marker (PSR546) was closely linked (8±2.4 cM) to the Lr9 gene and the other four DNA markers. As this marker maps to the distal part of the long arm of chromosome 6B of wheat, Lr9 and the other DNA markers also map to the distal region of 6BL. All three PCR markers detected the Lr9 gene in independently derived breeding lines and varieties, thus proving their general applicability in wheat breeding programs.  相似文献   

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