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1.
Alzate-Marin AL Menarim H de Carvalho GA de Paula TJ de Barros EG Moreira MA 《Phytopathology》1999,89(4):281-285
ABSTRACT Three F(2) populations derived from crosses between the resistant cultivar AB 136 and the susceptible cultivar Michelite (MiA), and one F(2) population derived from a cross between AB 136 and Mexico 222 (MeA), were used to identify markers linked to anthracnose resistance genes present in cultivar AB 136. Primer OPZ04 produced a DNA band (OPZ04(560)) linked in coupling phase to the resistance gene for pathotype 89 (8.5 +/- 0.025 cM) in one population derived from the cross MiA. In the same population, primer OPZ09 produced one band (OPZ09(950)) linked in repulsion phase (20.4 +/- 0.014 cM) to the same resistance gene. The simultaneous use of markers in coupling and in repulsion phases allowed the identification of the three genotypic classes. In the other two populations from cross MiA, OPZ04(560) was linked in coupling phase to resistance genes for pathotypes 73 (2.9 +/- 0.012 cM) and 81 (2.8 +/- 0.017 cM). In population MeA, OPZ04(560) was linked in coupling phase (7.5 +/- 0.033 cM) to resistance to pathotype 64. These data suggest that a single gene or complex locus of linked resistance genes present in cultivar AB 136 confers resistance to all four pathotypes of C. lindemuthianum. 相似文献
2.
ABSTRACT Septoria speckled leaf blotch (SSLB) caused by Septoria passerinii is a common disease in barley. SSLB resistance genes Rsp1, Rsp2, and Rsp3 have previously been identified in the United States Department of Agriculture National Small Grains collection accessions CIho 14300, CIho 4780, and CIho 10644, respectively. Populations of 100 to 120 F(2) individuals were evaluated for SSLB resistance in the greenhouse. Inheritance was evaluated in F(2:3)-derived families in the field. Partial molecular maps for three Rsp genes were constructed on F(2) and F(2:3) families derived from crosses between Robust and the resistant accessions CIho 14300, CIho 4780, and CIho 10644. The resistant locus Rsp1 was mapped to the short arm of chromosome 3H with two flanking diversity arrays technology (DArT) markers, bPb-6978 (8.9 cM) and bPb-9945 (16.3 cM), and two random amplified polymorphic DNA (RAPD) markers, OPC2(441R) (3.0 cM) and UBC285(158R) (4.3 cM). The genes Rsp2 and Rsp3 were positioned on the short arm of barley chromosome 1H with two restriction fragment length polymorphism (RFLP), six DArT, and three RAPD markers. An RFLP marker, MWG938, and an RAPD marker, OPAH5(545C), were tightly associated with Rsp2 at a distance of 0 cM. Five DArT markers spanning the short arm of 1H surrounded Rsp3 at a distance of 2.3 and 5.8 cM, while two RAPD markers-OPBA12(314C) (2.4 cM) in coupling and OPB17(451R) (3.5 cM) in repulsion-flanked Rsp3. Molecular marker data associated with Rsp2 and Rsp3 indicated that the two genes are closely linked on chromosome 1HS. A total of 17 of 154 simple sequence repeats (SSRs) tested were associated with Rsp genes on chromosome 1H and 3H, and they were also integrated into genetic linkage maps of the three F(2) Robust populations. Knowledge about the map position of Rsp genes on barley chromosomes will be useful for breeding for SSLB resistance in barley and eventual gene cloning. 相似文献
3.
ABSTRACT Five random amplified polymorphic DNA markers, two in coupling (OPAH5(545C), and OPBA12(314C)) and three in repulsion phase (UBC285(158R), OPC2(441R), and OPB17(451R)), closely linked to Rsp genes conferring resistance to Septoria speckled leaf blotch (SSLB), were identified using bulked segregant analysis in three F(2) populations, each containing a Rsp gene. These markers were converted into the sequence tagged site (STS) markers SUBC285, SOPC2, SOPAH5, and SOPBA12. Another STS marker (MWG938) linked to Rsp2 in coupling phase was also identified in an F(2) population from the cross Robust/CIho 4780. The STS markers were tested on a set of 42 resistant and susceptible barley germplasm lines and 98 landraces. The expected sizes of marker fragments associated with each allele at Rsp loci were present in resistant or susceptible accessions. Efficiency of marker-assisted selection (MAS) for Rsp1, Rsp2, and Rsp3 using STS markers were evaluated in three F(23) populations in the greenhouse and the field. Results of testing F(23) progeny demonstrated that the accuracy of MAS was, with one exception, greater than 97% in the greenhouse and in two field locations (90% in the Osnabrock, ND trial for Rsp2). The STS markers closely linked to Rsp genes also identified the SSLB resistance corresponding to Rsp1, Rsp2, or Rsp3 in gene pyramiding F(2) populations. The STS markers tightly linked to Rsp genes may be useful for M and for pyramiding with other genes in barley breeding for SSLB resistance. 相似文献
4.
Resistance to the eight races (3, 7, 19, 31, 81, 449, 453, and 1545) of the pathogenic fungus Colletotrichum lindemuthianum (anthracnose) was evaluated in F(3) families derived from the cross between the anthracnose differential bean cultivars Kaboon and Michelite. Molecular marker analyses were carried out in the F(2) individuals in order to map and characterize the anthracnose resistance genes or gene clusters present in Kaboon. The analysis of the combined segregations indicates that the resistance present in Kaboon against these eight anthracnose races is determined by 13 different race-specific genes grouped in three clusters. One of these clusters, corresponding to locus Co-1 in linkage group (LG) 1, carries two dominant genes conferring specific resistance to races 81 and 1545, respectively, and a gene necessary (dominant complementary gene) for the specific resistance to race 31. A second cluster, corresponding to locus Co-3/9 in LG 4, carries six dominant genes conferring specific resistance to races 3, 7, 19, 449, 453, and 1545, respectively, and the second dominant complementary gene for the specific resistance to race 31. A third cluster of unknown location carries three dominant genes conferring specific resistance to races 449, 453, and 1545, respectively. This is the first time that two anthracnose resistance genes with a complementary mode of action have been mapped in common bean and their relationship with previously known Co- resistance genes established. 相似文献
5.
ABSTRACT Crown rust of barley, caused by Puccinia coronata var. hordei, occurs sporadically and sometimes may cause yield and quality reductions in the Great Plains region of the United States and Canada. The incompletely dominant resistance allele Rpc1 confers resistance to P. coronata in barley. Two generations, F(2) and F(2:3), developed from a cross between the resistant line Hor2596 (CIho 1243) and the susceptible line Bowman (PI 483237), were used in this study. Bulked segregant analysis combined with random amplified polymorphic DNA (RAPD) primers were used to identify molecular markers linked to Rpc1. DNA genotypes produced by 500 RAPD primers, 200 microsatellites (SSRs), and 71 restriction fragment length polymorphism (RFLP) probes were applied to map Rpc1. Of these, 15 RAPD primers identified polymorphisms between resistant and susceptible bulks, and 62 SSR markers and 32 RFLP markers identified polymorphisms between the resistant and susceptible parents. The polymorphic markers were applied to 97 F(2) individuals and F(2:3) families. These markers identified 112 polymorphisms and were used for primary linkage mapping to Rpc1 using Map Manager QT. Two RFLP and five SSR markers spanning the centromere on chromosome 3H and one RAPD marker (OPO08-700) were linked with Rpc1 and, thus, used to construct a 30-centimorgan (cM) linkage map containing the Rpc1 locus. The genetic distance between Rpc1 and the closest marker, RAPD OPO08-700, was 2.5 cM. The linked markers will be useful for incorporating this crown rust resistance gene into barley breeding lines. 相似文献
6.
ABSTRACT A major gene for resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici = Erysiphe graminis f. sp. tritici) has been successfully transferred into hexaploid common wheat (Triticum aestivum, 2n = 6x = 42, AABBDD) from wild einkorn wheat (Triticum monococcum subsp. aegilopoides, 2n = 2x = 14, AA). NC96BGTA5 is a germ plasm line with the pedigree Saluda x 3/PI427662. The response patterns for powdery mildew resistance in NC96BGTA5 were tested with 30 differential isolates of B. graminis f. sp. tritici, and the line was resistant to all tested isolates. The analyses of P(1), P(2), F(1), F(2), and BC(1)F(1) populations derived from NC96BGTA5 revealed two genes for wheat powdery mildew resistance in the NC96BGTA5 line. One gene, Pm3a, was from its recurrent parent Saluda, and the second was a new gene introgressed from wild einkorn wheat. The gene was determined to be different from Pm1 to Pm21 by gene-for-gene and pedigree analyses. The new gene was identified as linked to the Pm3a gene based on the F(2) and BC(1)F(1) populations derived from a cross between NC96BGTA5 and a susceptible cultivar NK-Coker 68-15, and the data indicated that the gene was located on chromosome 1A. It is proposed that this new gene be designated Pm25 for wheat powdery mildew resistance in NC96BGTA5. Three random amplified polymorphic DNA markers, OPX06(1050), OPAG04(950), and OPAI14(600), were found to be linked to this new gene. 相似文献
7.
ABSTRACT Two strains of the wheat stem rust fungus, Puccinia graminis f. sp. tritici, were crossed on barberry, and a single F(1) progeny strain was selfed. The parents, F(1), and 81 F(2) progeny were examined for virulence phenotypes on wheat differential cultivars carrying stem rust resistance (Sr) genes. For eight Sr differentials, phenotypic ratios are suggestive of single dominant avirulence genes AvrT6, AvrT8a, AvrT9a, AvrT10, AvrT21, AvrT28, AvrT30, and AvrTU. Avirulence on the Sr; (Sr 'fleck') differential showed phenotypic ratios of approximately 15:1, indicating epistatic interaction of two genes dominant for avirulence. Avirulence on Sr9d favored a 3:13 over a 1:3 ratio, possibly indicating two segregating genes-one dominant for avirulence and one dominant for avirulence inhibition. Linkage analysis of eight single dominant avirulence genes and 970 DNA markers identified DNA markers linked to each of these avirulence genes. The closest linkages between AvrT genes and DNA markers were between AvrT6 and the random amplified polymorphic DNA marker crl34-155 (6 centimorgans [cM]) AvrT8a and the amplified fragment length polymorphism marker eAC/mCT-197 (6 cM) and between AvrT9a and the amplified fragment length polymorphism marker eAC/mCT-184 (6 cM). AvrT10 and AvrTU are linked at distance of 9 cM. 相似文献
8.
Kumar PN Sujatha K Laha GS Rao KS Mishra B Viraktamath BC Hari Y Reddy CS Balachandran SM Ram T Madhav MS Rani NS Neeraja CN Reddy GA Shaik H Sundaram RM 《Phytopathology》2012,102(2):222-228
Broadening of the genetic base for identification and transfer of genes for resistance to insect pests and diseases from wild relatives of rice is an important strategy in resistance breeding programs across the world. An accession of Oryza nivara, International Rice Germplasm Collection (IRGC) accession number 105710, was identified to exhibit high level and broad-spectrum resistance to Xanthomonas oryzae pv. oryzae. In order to study the genetics of resistance and to tag and map the resistance gene or genes present in IRGC 105710, it was crossed with the bacterial blight (BB)-susceptible varieties 'TN1' and 'Samba Mahsuri' (SM) and then backcrossed to generate backcross mapping populations. Analysis of these populations and their progeny testing revealed that a single dominant gene controls resistance in IRGC 105710. The BC(1)F(2) population derived from the cross IRGC 105710/TN1//TN1 was screened with a set of 72 polymorphic simple-sequence repeat (SSR) markers distributed across the rice genome and the resistance gene was coarse mapped on chromosome 7 between the SSR markers RM5711 and RM6728 at a genetic distance of 17.0 and 19.3 centimorgans (cM), respectively. After analysis involving 49 SSR markers located between the genomic interval spanned by RM5711 and RM6728, and BC(2)F(2) population consisting of 2,011 individuals derived from the cross IRGC 105710/TN1//TN1, the gene was fine mapped between two SSR markers (RMWR7.1 and RMWR7.6) located at a genetic distance of 0.9 and 1.2 cM, respectively, from the gene and flanking it. The linkage distances were validated in a BC(1)F(2) mapping population derived from the cross IRGC 105710/SM//2 × SM. The BB resistance gene present in the O. nivara accession was identified to be novel based on its unique map location on chromosome 7 and wider spectrum of BB resistance; this gene has been named Xa33. The genomic region between the two closely flanking SSR markers was in silico analyzed for putatively expressed candidate genes. In total, eight genes were identified in the region and a putative gene encoding serinethreonine kinase appears to be a candidate for the Xa33 gene. 相似文献
9.
小簇麦易位系V9128-3抗条锈病基因的遗传分析和SSR分子标记 总被引：2，自引：0，他引：2
用7个我国当前流行的条锈菌生理小种对V9128-3的抗条锈性进行了评价,表明本易位系对我国优势流行小种具有良好的抗病性。以Su-4对V9128-3与铭贤169配置的F1、BC1F1、F2及F3代群体进行了遗传分析,并对其中1个F2群体进行了SSR标记,再用BC1F1群体的部分单株和F3家系进行连锁标记的初步验证。遗传分析表明了V9128-3对Su-4的抗病性由1对显性核基因独立控制,从219对SSR引物中筛选到2个位于2AL上的该基因YrHV(暂命名)两侧的标记Xgwm356和Xwmc658,遗传距离分别为8.5和5.6cM,所用部分BC1F1单株和F3家系验证了该2个标记与YrHV连锁性。将此标记可用于小麦抗条锈病分子标记辅助育种。 相似文献
10.
普通小麦品种陕旱8675中抗条锈病基因的分子定位 总被引：1，自引：0，他引：1
利用SSR标记技术对小麦品种陕旱8675的抗条锈病基因进行了分子标记定位。通过对290对微卫星引物的筛选,发现Xwmc170和Xcfa20432对引物在抗亲、感亲、抗池和感池之间均有多态。群体分析结果表明,Xwmc170和Xcfa2043与陕旱8675中抗病基因相连锁,遗传距离分别为9.8 cM和15.0 cM,基因和标记之间的顺序为着丝点-Xcfa2043-Xwmc170-YrSh,间隔距离分别为19.05、5.2和9.8 cM。根据作图的结果,将陕旱8675中所含有的抗病基因定位于2A染色体长臂上,根据该基因的作图位置与抗谱分析,认为该基因可能是1个新的抗条锈基因,暂定名为YrSh。 相似文献
11.
小麦品种贵农22 抗条锈基因的遗传分析及分子标记 总被引：2，自引：0，他引：2
贵农22 是由簇毛麦、硬粒小麦以及普通小麦杂交选育而成的普通小麦品种,其对我国目前所有已知条锈菌生理小种均表现高度抗病。为了明确其抗条锈性遗传基础,并对抗条锈基因进行分子作图,本研究选用条锈菌重要小种CYR29、CYR30、CYR32、CYR33 和Su11鄄11,对贵农22 与条锈病感病品种辉县红或铭贤169 杂交F2 代、BC1 F1 代、BC1 F2 代进行抗锈性遗传分析,并对贵农22 控制Su11鄄11 抗病性的1 对隐性基因进行SSR 标记。结果表明,贵农22 至少含有3 对抗条锈病基因。利用272 株贵农22 / 铭贤169 BC1 F2 群体筛选到2 个与贵农22 控制Su11鄄11 抗性的隐性基因连锁的SSR 标记Xwmc44 和Xcfa2147,遗传距离分别为5. 1 和7. 3 cM,并将抗病基因定位于小麦1BL 上,暂命名为YrGn22。基因来源、抗病性分析以及分子检测结果表明,YrGn22 不同于1BL 上的已知小麦抗条锈病基因Yr3、Yr9、Yr21 和Yr29,可能是1 个新基因。 相似文献
12.
ABSTRACT Most barley cultivars are resistant to stripe rust of wheat that is caused by Puccinia striiformis f. sp. tritici. The barley cv. Steptoe is susceptible to all identified races of P. striiformis f. sp. hordei (PSH), the barley stripe rust pathogen, but is resistant to most P. striiformis f. sp. tritici races. To determine inheritance of the Steptoe resistance to P. striiformis f. sp. tritici, a cross was made between Steptoe and Russell, a barley cultivar susceptible to some P. striiformis f. sp. tritici races and all tested P. striiformis f. sp. hordei races. Seedlings of parents and F(1), BC(1), F(2), and F(3) progeny from the barley cross were tested with P. striiformis f. sp. tritici races PST-41 and PST-45 under controlled greenhouse conditions. Genetic analyses of infection type data showed that Steptoe had one dominant gene and one recessive gene (provisionally designated as RpstS1 and rpstS2, respectively) for resistance to races PST-41 and PST-45. Genomic DNA was extracted from the parents and 150 F(2) plants that were tested for rust reaction and grown for seed of F(3) lines. The infection type data and polymorphic markers identified using the resistance gene analog polymorphism (RGAP) technique were analyzed with the Mapmaker computer program to map the resistance genes. The dominant resistance gene in Steptoe for resistance to P. striiformis f. sp. tritici races was mapped on barley chromosome 4H using a linked microsatellite marker, HVM68. A linkage group for the dominant gene was constructed with 12 RGAP markers and the microsatellite marker. The results show that resistance in barley to the wheat stripe rust pathogen is qualitatively inherited. These genes might provide useful resistance against wheat stripe rust when introgressed into wheat from barley. 相似文献
13.
ABSTRACT Septoria tritici leaf blotch (STB), caused by the ascomycete Mycosphaerella graminicola (anamorph Septoria tritici), is an economically important disease of wheat. Breeding for resistance to STB is the most effective means to control this disease and can be facilitated through the use of molecular markers. However, molecular markers linked to most genes for resistance to STB are not yet available. This study was conducted to test for resistance in the parents of a standard wheat mapping population and to map any resistance genes identified. The population consisted of 130 F(10) recombinant-inbred lines (RILs) from a cross between the synthetic hexaploid wheat W7984 and cv. Opata 85. Genetic analysis indicated that a single major gene controls resistance to M. graminicola in this population. This putative resistance gene is now designated Stb8 and was mapped with respect to amplified fragment length polymorphism (AFLP) and microsatellite markers. An AFLP marker, EcoRI-ACG/MseI-CAG5, was linked in repulsion with the resistance gene at a distance of approximately 5.3 centimorgans (cM). Two flanking microsatellite markers, Xgwm146 and Xgwm577, were linked to the Stb8 gene on the long arm of wheat chromosome 7B at distances of 3.5 and 5.3 cM, respectively. The microsatellite markers identified in this study have potential for use in marker-assisted selection in breeding programs and for pyramiding of Stb8 with other genes for resistance to M. graminicola in wheat. 相似文献
14.
ABSTRACT In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides family (C9425DD). Previous field results were confirmed in the controlled environment of a growth chamber through an excised whole-leaf inoculation method. Using bulked segregant analysis we identified two random amplified polymorphic DNA (RAPD) markers (OPG10(340) and OPZ19(1800)) that are linked to Lrd1. Based on segregation in a total of 116 progeny, the genetic distances between OPG10(340) and OPZ19(1800) and the resistance locus were estimated as 2.6 and 7.4 Haldane centimorgans (cM), respectively. Multipoint linkage analyses strongly suggest the most likely order for these loci is Lrd1, OPG10(340), and OPZ19(1800). These markers may prove to be instrumental in the eventual cloning of Lrd1, as well as for marker-assisted selection of leaf-rust resistant genotypes. 相似文献
15.
H122是1个通过杂交和回交选育的普通小麦-华山新麦草易位系。为明确其抗条锈病基因及遗传特点,建立抗病基因SSR标记,利用我国小麦条锈菌流行小种CYR29、CYR31、CYR32、CYR33和致病类型Su11-4、Su11-11对H122进行苗期抗性鉴定,根据鉴定结果选用CYR32、CYR33和Su11-4对其与铭贤169杂交F1、F2及BC1代进行了遗传分析,同时应用258对SSR引物对将H122/铭贤169 F2代接种Su11-4的185个单株构建的作图群体进行了PCR扩增和电泳分析。结果表明,H122对供试小种均表现免疫或近免疫,对CYR32的抗病性由1对显性基因控制,对CYR33的抗病性由1对隐性基因控制,对Su11-4的抗病性亦由1对显性基因控制,将其暂命名为YrH122。筛选到3个与YrH122连锁的SSR标记Xbarc229、Xwmc339和Xwmc93,遗传距离分别为7.7、4.3和11.0 cM,并将该基因定位于小麦染色体1DL上。SSR标记回检显示,YrH122来源于华山新麦草。通过基因来源、分子检测及染色体位点比较,YrH122可能是1个不同于目前已知抗条锈病基因的新基因。 相似文献
16.
ABSTRACT Wheat (Triticum aestivum) cultivar Pavon 76 carries slow-rusting resistance to leaf rust that has remained effective in Mexico since its release in 1976. 'Pavon 76' was crossed with two leaf rust-susceptible wheat cultivars, Jupateco 73S and Avocet S, and between 118 and 148 individual F(2) plant-derived F(3) and F(5) lines were evaluated for adult-plant leaf rust resistance at two field sites in Mexico during different seasons. Evaluation of F(1) plants and parents indicated that the slow-rusting resistance was partially dominant. Segregation in the F(3) and F(5) indicated that the resistance was based on two genes with additive effects. Monosomic analysis was carried out to determine the chromosomal locations of the resistance genes. For this purpose, two or three backcross-derived cytogenetic populations were developed by crossing 'Pavon 76' with a monosomic series of adult-plant leaf rust-susceptible cultivar Lal-bahadur. Evaluation of such BC(2)F(3) and BC(3)F(3) lines from 16 confirmed 'Lalbahadur' monosomics indicated that one slow-rusting gene was located in chromosome 1B of 'Pavon 76'. This gene, designated as Lr46, is the second named gene involved in slow-rusting resistance to leaf rust in wheat. 相似文献
17.
M. Iruela P. Castro J. Rubio J. I. Cubero C. Jacinto T. Millán J. Gil 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):29-37
Ascochyta blight caused by Ascochyta rabiei and fusarium wilt caused by Fusarium oxysporum. f. sp. ciceris are the two most serious diseases of chickpea (Cicer arietinum). Quantitative trait loci (QTL) or genes for ascochyta blight resistance and a cluster of resistance genes for several fusarium
wilt races (foc1, foc3, foc4 and foc5) located on LG2 of the chickpea map have been reported independently. In order to validate these results and study the linkage
relationship between the loci that confer resistance to blight and wilt, an intraspecific chickpea recombinant inbred lines
(RIL) population that segregates for resistance to both diseases was studied. A new LG2 was established using sequence tagged
microsatellite sites (STMS) markers selected from other chickpea maps. Resistance to race 5 of F. oxysporum (foc5) was inherited as a single gene and mapped to LG2, flanked by the STMS markers TA110 (6.5 cM apart) and TA59 (8.9 cM apart).
A QTL for resistance to ascochyta blight (QTLAR3) was also detected on LG2 using evaluation data obtained separately in two cropping seasons. This genomic region, where QTLAR3 is located, was highly saturated with STMS markers. STMS TA194 appeared tightly linked to QTLAR3 and was flanked by the STMS markers TR58 and TS82 (6.5 cM apart). The genetic distance between foc5 and QTLAR3 peak was around 24 cM including six markers within this interval. The markers linked to both loci could facilitate the pyramiding
of resistance genes for both diseases through MAS. 相似文献
18.
Amplified fragment length polymorphism markers linked to a major quantitative trait locus controlling scab resistance in wheat 总被引：1，自引：0，他引：1
ABSTRACT Scab is a destructive disease of wheat. To accelerate development of scab-resistant wheat cultivars, molecular markers linked to scab resistance genes have been identified by using recombinant inbred lines (RILs) derived by single-seed descent from a cross between the resistant wheat cultivar Ning 7840 (resistant to spread of scab within the spike) and the susceptible cultivar Clark. In the greenhouse, F(5), F(6), F(7), and F(10) families were evaluated for resistance to spread of scab within a spike by injecting about 1,000 conidiospores of Fusarium graminearum into a central spikelet. Inoculated plants were kept in moist chambers for 3 days to promote initial infection and then transferred to greenhouse benches. Scab symptoms were evaluated four times (3, 9, 15, and 21 days after inoculation). The frequency distribution of scab severity indicated that resistance to spread of scab within a spike was controlled by a few major genes. DNA was isolated from both parents and F(9) plants of the 133 RILs. A total of 300 combinations of amplified fragment length polymorphism (AFLP) primers were screened for polymorphisms using bulked segregant analysis. Twenty pairs of primers revealed at least one polymorphic band between the two contrasting bulks. The segregation of each of these bands was evaluated in the 133 RILs. Eleven AFLP markers showed significant association with scab resistance, and an individual marker explained up to 53% of the total variation (R(2)). The markers with high R(2) values mapped to a single linkage group. By interval analysis, one major quantitative trait locus for scab resistance explaining up to 60% of the genetic variation for scab resistance was identified. Some of the AFLP markers may be useful in marker-assisted breeding to improve resistance to scab in wheat. 相似文献
19.
ABSTRACT DNA markers tightly linked to resistance (R) genes provide a very powerful tool for both marker-assisted selection in plant breeding and positional cloning of R genes. In the present study, a linkage of random amplified polymorphic DNA (RAPD) markers to the single dominant gene (Cr2) for resistance to white pine blister rust fungus (Cronartium ribicola) was investigated in western white pine (Pinus monticola). A mapping population of 128 individual megagametophytes was generated from seeds of a heterozygous resistant tree (Cr2/cr2), and the corresponding seedlings of each megagametophyte were subjected to the test of phenotype segregation by inoculation with C. ribicola. Bulked segregant analysis and haploid segregation analysis identified eight robust RAPD markers linked to Cr2. This constitutes the first Cr2 genetic linkage map spanning 84.7 cM with four markers only 3.2 cM from Cr2. One sequence (U256-1385) of these linked markers was significantly similar to the Ty3/gypsy-like long terminal direct repeats retrotransposons. Another marker, U570-843, had no significant similarity to any entry in either GenBank or the loblolly genomics data bank. As presumed that the average physical distance per centimorgan is about 10 Mb in P. monticola, it is probably unrealistic to use these DNA markers for positional cloning of the Cr2 gene. 相似文献
20.
ABSTRACT A gene-for-gene interaction was previously suggested by mapping of a single major locus (LEM 1) controlling cotyledon resistance to Leptosphaeria maculans isolate PHW1245 in Brassica napus cv. Major. In this study, we obtained further evidence of a gene-for-gene interaction by studying the inheritance of the corresponding avirulence gene in L. maculans isolate PHW1245. The analysis of segregating F(1) progenies and 14 test crosses suggested that a single major gene is involved in the interaction. This putative avirulence gene was designated alm1 after the resistance locus identified in B. napus. Amplified fragment length polymorphism (AFLP) markers were used to generate a rudimentary genetic linkage map of the L. maculans genome and to locate markers linked to the putative avirulence locus. Two flanking AFLP markers, AC/TCC-1 and AC/CAG-5, were linked to alm1 at 3.1 and 8.1 cM, respectively. Identification of markers linked to the avirulence gene indicated that the differential interaction is controlled by a single gene difference between parental isolates and provides further support for the gene-for-gene relationship in the Leptosphaeria-Brassica system. 相似文献