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1.
S. R. Barman    M. Gowda    R. C. Venu  B. B. Chattoo 《Plant Breeding》2004,123(3):300-302
Analysis of near‐isogenic lines (NILs) indicated the presence of a novel resistance gene in the indica rice cultivar ‘Tetep’ which was highly resistant to the rice blast fungus Magnaporthe grisea.‘Tetep’ was crossed to the widely used susceptible cultivar ‘CO39’ to generate the mapping population. A Mendelian segregation ratio of 3 : 1 for resistant to susceptible F2 plants further confirmed the presence of a major dominant locus, in ‘Tetep’, conferring resistance to the blast fungal isolate B157, corresponding to the international race IC9. Simple sequence length polymorphism (SSLP) was used for molecular genetic analysis. The analysis revealed that the SSLP marker RM 246 was linked to a novel blast resistance gene designated Pi‐tp(t) in ‘Tetep’.  相似文献   

2.
We investigated the mode of inheritance and map location of field resistance to rice blast in the elite rice strain Chubu 111, and yield under severe blast conditions. Chubu 111 carries the complete resistance gene Pii, although field testing showed this strain to be susceptible to infection. The level of field resistance of Chubu 111 was so high that chemicals used to control blast were not required, even in an epiphytotic area. Genetic analysis of field resistance to blast in 149 F3 lines derived from a cross between Chubu 111 and the susceptible cultivar ‘Mineasahi’ suggested that field resistance is controlled by a dominant gene, designated Pi39(t), that cosegregates with the single sequence repeat marker loci RM3843 and RM5473 on chromosome 4. Comparative studies of polymorphism at RM3843 among Chubu 111 and six cultivars or lines in its pedigree suggested that the donor of the resistance gene was the Chinese cultivar ‘Haonaihuan’. Marker‐assisted selection of Pi39(t) should be useful in rice‐breeding programmes for field resistance to blast.  相似文献   

3.
Amplified fragment length polymorphism (AFLP) and microsatellite (simple sequence repeat, SSR) techniques were used to map the _RGSpeking gene, which is resistant to most isolates of Cercospora sojina in the soya bean cultivar ‘Peking’. The mapping was conducted using a defined F2 population derived from the cross of ‘Peking’(resistant) בLee’(susceptible). Of 64 EcoRI and MseI primer combinations, 30 produced polymorphisms between the two parents. The F2 population, consisting of 116 individuals, was screened with the 30 AFLP primer pairs and three mapped SSR markers to detect markers possibly linked to RcsPeking. One AFLP marker amplified by primer pair E‐AAC/M‐CTA and one SSR marker Satt244 were identified to be linked to ResPeking. The gene was located within a 2.1‐cM interval between markers AACCTA178 and Satt244, 1.1 cM from Satt244 and 1.0 cM from AACCTA178. Since the SSR markers Satt244 and Satt431 have been mapped to molecular linkage group (LG) J of soya bean, the ResPeking resistance gene was putatively located on the LG J. This will provide soya bean breeders an opportunity to use these markers for marker‐assisted selection for frogeye leaf spot resistance in soya bean.  相似文献   

4.
G. Y. Lu    G. S. Yang  T. D. Fu 《Plant Breeding》2004,123(3):262-265
Rs1046AB is a genic male sterile two‐type line in rapeseed that has great potential for hybrid seed production. The sterility of this line is conditioned by the interaction of two genes, i.e. the dominant genic male sterility gene (Ms) and the suppressor gene (Rf). The present study was undertaken to identify DNA markers for the Ms locus in a BC1 population developed from a cross between a male‐sterile plant in Rs1046AB and the fertile canola‐type cultivar ‘Samourai’. Bulked segregant analysis was performed using the amplified fragment length polymorphism (AFLP) methodology. From the survey of 480 AFLP primer combinations, five AFLP markers (P10M13350, P13M8400, P6M6410, E7M1230 and E3M15100) tightly linked to the target gene were identified. Two of them, E3M15100 and P6M6410, located the closest, at either side of Ms at a distance of 3.7 and 5.9 cM, respectively. The Ms locus was subsequently mapped on linkage group LG10 in the map developed in this laboratory, adding two additional markers weakly linked to it. This suite of markers will be valuable in designing a marker‐assisted genic male sterility three‐line breeding programme.  相似文献   

5.
K. Williams    P. Bogacki    L. Scott    A. Karakousis  H. Wallwork   《Plant Breeding》2001,120(4):301-304
Seedlings of the barley line ‘B87/14’ were resistant to 22 out of 23 Australian isolates of Rhynchosporium secalis, the causal agent of leaf scald.‘B87/14’‐based populations were developed to determine the location of the resistance locus. Scald resistance segregated as a single dominant trait in BC1F2 and BC1F3 populations. Bulked segregant analysis identified amplified fragment length polymorphisms (AFLPs) with close linkage to the resistance locus. Fully mapped populations not segregating for scald resistance located these AFLP markers on chromosome 3H, possibly within the complex Rrs1 scald locus. Microsatellite and restriction fragment length polymorphism markers adjacent to the AFLP markers were identified and validated for their linkage to scald resistance in a second segregating population, with the closest marker 2.2 cM from the resistance locus. These markers can be used for selection of the Rrs.B87 scald‐resistance locus, and other genes at the chromosome 3H Rrs1 locus.  相似文献   

6.
Y. Weng  M. D. Lazar 《Plant Breeding》2002,121(3):218-223
The greenbug, Schizaphis graminum (Rondani), is the most economically damaging aphid pest of wheat in the southern Great Plains of the USA. In this study, the single, dominant greenbug resistance gene, Gb3, was molecularly tagged and genetically mapped using amplified fragment length polymorphism (AFLP) and simple sequence repeat(SSR) markers. Three AFLP loci were associated with the Gb3 locus in linkage analysis with 75 F2:3 families from the cross between two near‐isogenic lines (NILs) for Gb3,‘TXGBE273’ and ‘TXGBE281′. Two of these loci, XMgcc Pagg and Xmagg Patg cosegregate with Gb3 in the population analysed. Further analysis indicated that XMgcc Pagg and Xmagg Patg are specific for the Gb3 locus in diverse genetic backgrounds. Two SSR markers, Xgwm111 and Xgwm428 previously mapped in wheat chromosome 7D, were shown to be linked with Gb3, 22.5 cM and 33.1 cM from Gb3, respectively, in an F2 population of ‘Largo’בTAM 107’, suggesting that Gb3 is located in the long arm of chromosome 7D. The two AFLP markers cosegregating with Gb3 are valuable tools in developing molecular markers for marker‐assisted selection of greenbug resistance in wheat breeding.  相似文献   

7.
S. Chen    C. G. Xu    X. H. Lin  Q. Zhang 《Plant Breeding》2001,120(2):133-137
Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (X00), is one of the most devastating diseases of rice world‐wide; it is also a serious problem of hybrid rice production in China. In this study, a molecular marker‐assisted introgression of Xa21, a gene highly resistant to a broad spectrum of Xoo strains, from ‘IRBB21’ was performed to improve the BB resistance of‘6078′, a new restorer line with high yielding potential. The entire process took one generation of crossing followed by three generations of backcrossing and one generation of selfing. The presence of Xa21 in each generation was determined by both polymerase chain reaction (PCR) and pathogen inoculation. Recombinations between Xa21 and flanking markers were identified by PCR analysis. Background selection was conducted in BC1F1 and BC2F1 using amplified fragment length polymorphism (AFLP) markers detecting a total of 129 polymorphic bands between‘6078’ and ‘IRBB21′. The individual selected in BC3F2, or‘6078′(Xa21), carried a fragment of less than 3.8 cM from the donor line in the Xa21 region on chromosome 11, and about 98.8% of the genetic background from the recurrent parent. The results showed that‘6078′(Xa21) had the same level and spectrum of BB resistance as the donor parent ‘IRBB21′, while maintaining the agronomic performance and combining ability of the original 6078. A significant increase in BB resistance was also achieved in the hybrid using 6078(Xa21) as the restorer line.  相似文献   

8.
Tef is an important cereal crop in Ethiopia. This study was conducted to investigate (1) genetic diversity within and among three Eragrostis species (E. tef, E. pilosa and E. curvula), and (2) the relationship between E. tef, E. pilosa and E. curvula. A total of 529 AFLP markers were obtained, out of which 58% (368) were polymorphic, using 10 primer, combinations. The three species were separated distinctly using amplified fragment length polymorphism (AFLP), However, diversity revealed at the morphological trait level was not commensurate with that observed for AFLP. This was due to the small number of morphological traits available and their interaction with the environment. Within tef, ‘Rubicunda’ and DZ‐01‐1093 were found to be distantly related to the rest of the tef accessions. The diversity within species was such that E. pilosa was the most diverse followed by E. curvula and E. tef. Moreover, E. pilosa was more closely related to E. tef than E. curvula. Therefore, further study is needed of E. pilosa accessions and of ‘Rubicunda’ and DZ‐01‐1093 in a crossing programme to generate a population for selection and/or genetic mapping. A total of 19 cultivars or accessions had one or more unique fragments using one or more AFLP primers, indicating the potential of the technology in fingerprinting tef in a breeding or seed multiplication programme.  相似文献   

9.
The rice cultivar ‘Chumroo’ is commonly cultivated in the mid- and high-altitude areas of Bhutan. This cultivar has shown durable blast resistance in that area, without evidence of breakdown, for over 20 years. Chumroo was inoculated with 22 blast isolates selected from the race differential standard set of Japan. The cultivar showed resistance to all the isolates. To identify the resistance gene(s), Chumroo was crossed with a susceptible rice cultivar, Koshihikari. The F1 plants of the cross showed resistance. Segregation analyses of 300 F3 family lines fitted the segregation ratio of 1:2:1 and indicated that a single dominant gene controls the resistance to a blast isolate Ao 92-06-2 (race 337.1). The Chumroo resistance locus (termed Pi46(t)) was mapped between two SSR markers, RM6748 and RM5473, on the terminal region of the long arm of chromosome 4, using linkage analysis with SSR markers. The nearest marker, RM5473, was linked to the putative resistance locus at a map distance of 3.2 cM. At the chromosomal region, no true resistance genes were identified, whereas two field resistance genes were present. Therefore, we designated Pi46(t) as a novel blast resistance locus.  相似文献   

10.
The present work was conducted to identify microsatellite markers linked to the rice blast resistance gene Pi-1(t) for a marker-assisted selection program. Twenty-four primer pairs corresponding to 19 microsatellite loci were selected from the Gramene database (www. gramene.org) considering their relative proximity to Pi-1(t) gene in the current rice genetic map. Progenitors and DNA bulks of resistant and susceptible families from F3 segregating populations of a cross between the near-isogenic lines C101LAC (resistant) and C101A51 (susceptible) were used to identify polymorphic microsatellite markers associated to this gene through bulked segregant analysis. Putative molecular markers linked to the blast resistance gene Pi-1(t) were then used on the whole progeny for linkage analysis. Additionally, the diagnostic potential of the microsatellite markers associated to the resistance gene was also evaluated on 17 rice varieties planted in Latin America by amplification of the specific resistant alleles for the gene in each genotype. Comparing with greenhouse phenotypic evaluations for blast resistance, the usefulness of the highly linked microsatellite markers to identify resistant rice genotypes was evaluated. As expected, the phenotypic segregation in the F3 generation agreed to the expected segregation ratio for a single gene model. Of the 24 microsatellite sequences tested, six resulted polymorphic and linked to the gene. Two markers (RM1233*I and RM224) mapped in the same position (0.0 cM) with the Pi-1(t) gene. Other three markers corresponding to the same genetic locus were located at 18.5 cM above the resistance gene, while another marker was positioned at 23.8 cM below the gene. Microsatellite analysis on elite rice varieties with different genetic background showed that all known sources of blast resistance included in this study carry the specific Pi-1(t) allele. Results are discussed considering the potential utility of the microsatellite markers found, for MAS in rice breeding programs aiming at developing rice varieties with durable blast resistance based on a combination of resistance genes. Centro Internactional de Agricultura Tropical (CIAT) institute where the research was carried out  相似文献   

11.
N. Saka    T. Tsuji    T. Toyama    M. Yano    T. Izawa    T. Sasaki 《Plant Breeding》2006,125(2):140-143
The chromosomal location of the resistance gene for green rice leafhopper (GRLH), an injurious insect for rice, has been determined and RFLP markers closely linked to this gene have been identified. The susceptible japonica rice variety ‘Nipponbare’ was crossed with a resistant japonica rice line ‘Aichi42’, in which green rice leaf hopper resistance had been introduced from an indica variety ‘Rantaj‐emas2’, and the 100 F2 plants obtained were used for linkage analysis. The green rice leafhopper resistance gene, Grh3(t), was mapped between RFLP markers C288B and C133A on chromosome 6 and co‐segregated with C81. Of the RFLP markers tightly linked to Grh3(t), C81 was converted to a SCAR marker and C133A to a cleaved amplified polymorphic sequence marker that could distinguish the heterozygous genotype to establish an effective marker‐aided selection system for the GRLH resistance gene.  相似文献   

12.
A single dominant blast resistance gene conferring resistance to a Korean rice blast isolate was identified in rice variety `Suweon 365'. We report the chromosomal localization and molecular mapping of this blast resistance gene designated as Pi-18, which confers resistance to Korean isolate `KI-313' of the blast pathogen. To know whether there is a relationship among genes conditioning resistance to location-specific isolates of the blast pathogen and thereby to identify linked markers to resistance gene for isolate KI-313 collected in Korea, RFLP markers previously reported to be linked to major blast resistance genes in different rice germplasm and other markers mapped to nearby regions were surveyed for polymorphism between a resistant (`Suweon 365') and a susceptible (`Chucheongbyeo') parent. Linkage associations of the RFLP markers with the resistance gene were verified using an F2 and F3 segregating population of known blast reaction. RFLP analysis showed that Pi-18 was located near the end of chromosome 11, linked to a single copy clone RZ536 at a distance of 5.4 centiMorgans (cM) and that this gene was different from Pi-1(t). An allelism test revealed that this gene was also different from Pi-k. Currently, a combination of RAPD and microsatellite primers is being employed to find additional markers in this region. Tightly linked DNA markers will facilitate selection for resistant genotypes in breeding programs and provide the basis for map based cloning of this new blast resistance gene. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
Amplified fragment length polymorphism (AFLP) markers linked to the Aegilops ventricosa‐derived chromosome segment in ‘VPM1’ on which the eyespot resistance gene, Pch1, and the endopeptidase gene, Ep‐D1b, occur were identified. One marker was isolated from the gel, cloned and sequenced. Sequence analysis revealed a microsatellite repeat motif. Sequence‐specific primers were designed to amplify a product containing the repeat motif, and the microsatellite marker was tested for cosegregation with the Ep‐D1b allele. Distinct alleles were produced by the Pch1 sources, normal wheat and wheat containing the Lr19 translocation. A recombination frequency of 0.02 was calculated between the microsatellite marker and Ep‐D1.  相似文献   

14.
The Pi-z gene in rice confers resistance to a wide range of races of the rice blast fungus, Magnaporthe oryzae. The objective of this study was to characterize Pi-z in 111 rice germplasm accessions using DNA markers and pathogenicity assays. The existence of Pi-z in rice germplasm was detected by using four simple sequence repeat (SSR) markers (RM527, AP4791, AP5659-1, AP5659-5) closely linked to Pi-z, and was verified using pathogenicity assays with an avirulent strain (IE1k) and two virulent races (IB33 and IB49). Among 111 germplasm accessions evaluated, 73 were found to contain the Pi-z gene using both SSR markers and pathogenicity assays. The remaining 38 germplasm accessions were found to be inconsistent in their responses to the blast races IB33, IEIk and IB49 with expected SSR marker alleles, suggesting the presence of unexpected SSR alleles and additional R gene(s). These characterized germplasm can be used for genetic studies and marker-assisted breeding for improving blast resistance in rice.  相似文献   

15.
The most important disease of Coffea arabica is coffee leaf rust caused by the fungus Hemileia vastatrix. The purpose of this study was to characterize the inheritance of coffee resistance gene(s) to race II of this pathogen and to identify and map molecular markers linked to this trait. Different populations were used: F2 (160 plants), BCr (20), and BCs (135), derived from a cross between the resistant genotype Híbrido de Timor UFV 427-15 and the susceptible cultivar Catuaí Amarelo UFV 2143-236 (IAC 30). The segregation analysis showed that the resistance of Híbrido de Timor to race II of the H. vastatrix is conferred by a single dominant gene. The amplification of 176 AFLP (Amplified fragment length polymorphism) primer combinations using bulked segregant analysis (BSA) allowed the identification of three molecular markers linked to the resistance gene. Genetic mapping of these three markers in the F2 population indicated that they are distributed on both sides, flanking the resistance gene. The markers E.CTC/M.TTT405 and E.CGT/M.TGT300 were found linked to the resistance gene at 8.69 cM (LOD 18.91) and 25.10 cM (LOD 5.37), respectively, while E.CCT/M.TTC230 was localized on the other side of the gene, at 20.50 cM (LOD 6.15). These markers are the first rust resistance markers identified in Híbrido de Timor and can be useful for marker assisted selection in coffee breeding programs.  相似文献   

16.
In order to study the function of blast resistance gene and estimate resistance scale to Pyricularia grisea Sacc., the cause of Rice Blast Disease in rice, we evaluated 58 rice genotypes for phenotypic and molecular assessment. Phenotypic tests were conducted in a blast upland nursery and also in the greenhouse by using specific races of blast IA-82 and IA-90 in the greenhouse and local races for the nursery. The traits assessed consisted of infection type (IT), percent diseased leaf area (DLA) (in both nursery and greenhouse), and lesion number (LN), lesion size (LS, mm2) only in greenhouse conditions. Molecular assessment was done by using three STS, JJ80, JJ81, and JJ113, and four microsatellite markers, RM224, RM277, RM463, and RM179 which are linked to resistance genes on rice chromosomes. Genotypes had different reactions against blast races in the phenotypic part of experiment. Consequently, all genotypes were divided into three groups with high, intermediate, and susceptible resistance. Our results indicated that partial resistant genotypes are preferable for achieving durable control. Eventually, the association test between molecular data and phenotypic results showed that there is a significant level for some of the SSR markers. This means there is at least one race-specific resistance gene in the genetic sources of these genotypes that bring about resistance functions to the blast races. These results demonstrated the existence of functional resistance genes in Iranian rice genotypes. Thus, these functional genes are responsible for some parts of resistance that have been measured in phenotypic tests. Our results could be useful for breeding programs to make some modifications in the rice germplasm and would also be applicable for the marker-assisted selection process.  相似文献   

17.
The sequence‐specific amplification polymorphism (S‐SAP) method, derived from the amplified fragment length polymorphism (AFLP) technique, produces amplified fragments containing retrotransposon long terminal repeat ( LTR ) sequence at one end and a host restriction site at the other. The development and application of this procedure to the LTR of the Vine‐1 element from grapevine is reported. Two primers derived from one of the LTR sequences flanking the retrotransposon were used in combination with MseI degenerated primers on 15 grapevine accessions. S‐SAP results were compared with AFLP data. The heterozygosity and gene diversity values were higher for S‐SAP than for the AFLP procedure. Results show that S‐SAP amplification is effective in identifying polymorphisms and defining genetic distances among cultivars, and could be used for fingerprinting and for ‘Traminer’ clone identification. To the contrary Vine‐1 retrotransposon‐based S‐SAP was not able to distinguish ‘Pinot’ clones.  相似文献   

18.
Y. H. Li    Z. H. Han  X. Xu 《Plant Breeding》2004,123(4):316-320
Malus xiaojinensis, one of the most important wild genotypes in the genus Malus, is resistant to a variety of stresses such as Fe deficiency chlorosis, drought and cold. However, lack of knowledge of its genetic background prevents using genetic analysis to study those agronomic traits and corresponding gene functions. Here, as the first step towards construction of the linkage map of M. xiaojinensis, genetic analysis of the F1 triploid hybrids (M. xiaojinensis × M. baccata) was performed with amplified fragment length polymorphism (AFLP) markers. Using 15 EcoRI‐ MseI primer combinations, 1110 AFLPs were identified, with 31.3% of M. xiaojinensis‐, 12.7% of M. baccata‐specific markers, 54.9% of common markers, and 1.2% of non‐parental markers; 93.3% of the AFLP markers exhibit the expected segregation ratio. Thirty‐two M. xiaojinensis‐specific markers and 47 common markers display a 5 : 1 and 11:1 segregation ratios, respectively, suggesting that M. xiaojinensis is an autotetraploid, or at least an isosyndetic allotetraploid.  相似文献   

19.
Gall midge is the third most destructive insect pests of rice after stem borers and planthoppers. Host plant resistance has been recognized as the most effective and economic, means for gall midge management. With the characterization of a new gall midge biotype (GMB) 4M, unique feature of gall midge resistance in the breeding line CR57-MR1523 was highlighted. Multi-location evaluation of F3 families derived from the cross TN1 × CR57-MR1523 against different gall midge biotypes helped to identify a new dominant gene conferring resistance against GMB4. This gene has been designated as Gm11t. Though CR57-MR1523 has been extensively used in breeding gall midge resistant rice varieties like Suraksha, neither the genetics of resistance nor chromosomal location of the resistance gene(s) is known. In the present study we have tagged and mapped the new gall midge resistance gene, Gm11t, on chromosome 12, using SSR markers. To map the gene locus, 466 F10 generation Recurrent Inbred Lines (RILs), from the cross of TN1 × CR57-MR1523 were used. Of the 471 SSR markers spread across the rice genome, 56 markers showed polymorphism and were used to screen a subset of the mapping population consisting of 10 resistant (R) and 10 susceptible (S) F10 RILs. Six SSR markers, RM28706, RM235, RM17, RM28784, RM28574 and RM28564 on chromosome 12 were initially found to be associated with resistance and susceptibility. Based on the linkage analysis in selected 158 RILs, we were able to map the locus between two flanking SSR markers, RM28574 and RM28706, on chromosome 12 within 4.4 and 3.8 cM, respectively. Further, two NILs with 99% genetic similarity, were identified from the RILs which differed in gall midge resistance. The tightly linked flanking SSR markers will facilitate marker-assisted gene pyramiding and map-based cloning of the resistant gene. NILs would be valuable materials for functional analysis of the identified candidate gene.  相似文献   

20.
B. Uzun    D. Lee    P. Donini  M. L Ça&#;irgan 《Plant Breeding》2003,122(1):95-97
The identification of an amplified fragment length polymorphism (AFLP) marker linked to an agronomically useful trait in sesame is reported. A bulked segregant analysis (BSA) approach was adopted on segregating progenies of a cross between the closed capsule mutant line ‘cc3’, and the Turkish variety ‘Muganli‐57′. A total of 72 primer combinations were screened for linkage to the trait, but only one closely linked amplified fragment length polymorphism (AFLP) marker was identified. The linkage was confirmed by analysing the AFLP profile from single plants. The marker has the potential to accelerate breeding programmes aimed at modifying unwanted side‐effects of the closed capsule mutation by marker‐assisted selection.  相似文献   

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