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1.
M. Yamamori 《Euphytica》2009,165(3):607-614
In common and durum wheats (Triticum aestivum L. and T. durum Desf.), variant waxy (Wx) alleles have been reported for three Wx proteins (Wx-A1, -B1 and -D1), responsible for amylose synthesis in flour starch.
Five variant alleles, Wx-A1c, -A1e, -B1c, -B1d and -D1c, were examined to elucidate their effects on amylose content in flour starch. Common wheat lines carrying a Wx protein produced
by one variant (e.g., Wx-A1c) and one control (e.g., Wx-A1a) allele were bred and their starches were compared. Results showed that Wx-A1e did not produce amylose (waxy phenotype), whereas three alleles (Wx-A1c, -B1c and -B1d) reduced amylose, and -D1c might have increased it slightly. Most data on blue value, swelling power and starch paste clarity in water and dimethyl
sulphoxide also suggested the variant Wx alleles either reduced or increased amylose content. 相似文献
2.
Brent D. McCallum D. Gavin Humphreys Daryl J. Somers Abdulsalam Dakouri Sylvie Cloutier 《Euphytica》2012,183(2):261-274
The wheat (Triticum aestivum L.) gene Lr34/Yr18 conditions resistance to leaf rust, stripe rust, and stem rust, along with other diseases such as powdery mildew. This makes
it one of the most important genes in wheat. In Canada, Lr34 has provided effective leaf rust resistance since it was first incorporated into the cultivar Glenlea, registered in 1972.
Recently, molecular markers were discovered that are either closely linked to this locus, or contained within the gene. Canadian
wheat cultivars released from 1900 to 2007, breeding lines and related parental lines, were tested for sequence based markers
caSNP12, caIND11, caIND10, caSNP4, microsatellite markers wms1220, cam11, csLVMS1, swm10, csLV34, and insertion site based
polymorphism marker caISBP1. Thirty different molecular marker haplotypes were found among the 375 lines tested; 5 haplotypes
had the resistance allele for Lr34, and 25 haplotypes had a susceptibility allele at this locus. The numbers of lines in each haplotype group varied from 1
to 140. The largest group was represented by the leaf rust susceptible cultivar “Thatcher” and many lines derived from “Thatcher”.
The 5 haplotypes that had the resistance allele for Lr34 were identical for the markers tested within the coding region of the gene but differed in the linked markers wms1220, caISBP1,
cam11, and csLV34. The presence of the resistance or susceptibility allele at the Lr34 locus was tracked through the ancestries of the Canadian wheat classes, revealing that the resistance allele was present
in many cultivars released since the 1970s, but not generally in the older cultivars. 相似文献
3.
Grain hardness plays an important role in determining both milling performance and quality of the end-use products produced
from common or bread wheat. The objective of this study was to characterize allelic variations at the Pina and Pinb loci in Xinjiang wheat germplasm for further understanding the mechanisms involved in endosperm texture formation, and the
status of grain texture in Chinese bread wheat. A total of 291 wheat cultivars, including 56 landraces, and 95 introduced
and 140 locally improved cultivars, grown in Xinjiang, were used for SKCS measurement and molecular characterization. Among
the harvested grain samples, 185 (63.6%), 40 (13.7%), and 66 (22.7%) were classified as hard, mixed and soft, respectively.
Eight different genotypes for the Pina and Pinb loci were identified, including seven previously reported genotypes, viz., Pina-D1a/Pinb-D1a, Pina-D1a/Pinb-D1b, Pina-D1b/Pinb-D1a, Pina-D1a/Pinb-D1p, Pina-D1a/Pinb-D1q, Pina-D1a/Pinb-D1aa, Pina-D1a/Pinb-D1ab, and a novel Pinb allele, Pinb-D1ac. This new allele, detected in Kashibaipi (local landrace) and Red Star (from Russia) has a double mutation at the 257th (G
to A substitution) and 382nd (C to T substitution) nucleotide positions of the coding region. Pina-D1b, Pinb-D1b, and Pinb-D1p were the most common alleles in Xinjiang wheat germplasm, with frequencies of 14.3%, 38.1% and 28.6% in hard textured landraces,
25.5%, 56.9% and 11.8% in hard introduced cultivars, and 24.8%, 47.8% and 26.5% in hard locally improved cultivars, respectively.
The restriction enzymes ApaI, SapI, BstXI and SfaNI were used to identify Pinb-D1ab or Pinb-D1ac, Pinb-D1b, Pinb-D1e and Pinb-Dg, respectively, by digesting PCR products of the Pinb gene. The unique grain hardness distribution in Xinjiang bread wheat, as well as the CAPs markers for identification of the
Pinb alleles provided useful information for breeding wheat cultivars with optimum grain textures.
Liang Wang and Genying Li—contributed equally to this work. 相似文献
4.
Franceli R. Kulcheski Felipe A. S. Graichen José A. Martinelli Ana B. Locatelli Luiz C. Federizzi Carla A. Delatorre 《Euphytica》2010,175(3):423-432
Crown rust, which is caused by Puccinia
coronata f. sp. avenae, P. Syd. & Syd., is the most destructive disease of cultivated oats (Avena
sativa L.) throughout the world. Resistance to the disease that is based on a single gene is often short-lived because of the extremely
great genetic diversity of P. coronata, which suggests that there is a need to develop oat cultivars with several resistance genes. This study aimed to identify
amplified fragment length polymorphism AFLP markers that are linked to the major resistance gene, Pc68, and to amplify the F6 genetic map from Pc68/5*Starter × UFRGS8. Seventy-eight markers with normal segregation were discovered and distributed in
12 linkage groups. The map covered 409.4 cM of the Avena
sativa genome. Two AFLP markers were linked in repulsion to Pc68: U8PM22 and U8PM25, which flank the gene at 18.60 and 18.83 centiMorgans (cM), respectively. The marker U8PM25 is located
in the linkage group 4_12 in the Kanota × Ogle reference oat population. These markers should be useful for transferring Pc68 to genotypes with good agronomic characteristics and for pyramiding crown rust resistance genes. 相似文献
5.
The Lr56/Yr38 translocation consists primarily of alien-derived chromatin with only the 6AL telomeric region being of wheat origin. To
improve its utility in wheat breeding, an attempt was made to exchange excess Ae. sharonensis chromatin for wheat chromatin through homoeologous crossover in the absence of Ph1. Translocation heterozygotes that lacked Ph1 were test-crossed with Chinese Spring nullisomic 6A tetrasomic 6B and nullisomic 6A-tetrasomic 6D plants and the resistant
(hemizygous 6A) progeny were analyzed with four microsatellite markers. Genetic mapping suggested general homoeology between
wheat chromosome 6A and the translocation chromosomes, and showed that Lr56 was located near the long arm telomere. Thirty of the 53 recombinants had breakpoints between Lr56 and the most distal marker Xgwm427. These were characterized with additional markers. The data suggested that recombinants #39, 157 and 175 were wheat chromosomes
6A with small intercalary inserts of foreign chromatin containing Lr56 and Yr38, located distally on the long arms. These three recombinants are being incorporated into adapted germplasm. Attempts to identify
the single shortest translocation and to develop appropriate markers are being continued. 相似文献
6.
Genetic Analysis of Resistance to Soil-Borne Wheat Mosaic Virus Derived from Aegilops tauschii. Euphytica. Soil-Borne Wheat Mosaic Virus (SBWMV), vectored by the soil inhabiting organism Polymyxa graminis, causes damage to wheat (Triticum aestivum) yields in most of the wheat growing regions of the world. In localized fields, the entire crop may be lost to the virus.
Although many winter wheat cultivars contain resistance to SBWMV, the inheritance of resistance is poorly understood. A linkage
analysis of a segregating recombinant inbred line population from the cross KS96WGRC40 × Wichita identified a gene of major
effect conferring resistance to SBWMV in the germplasm KS96WGRC40. The SBWMV resistance gene within KS96WGRC40 was derived
from accession TA2397 of Aegilops taushcii and is located on the long arm of chromosome 5D, flanked by microsatellite markers Xcfd10 and Xbarc144. The relationship of this locus with a previously identified QTL for SBWMV resistance and the Sbm1 gene conferring resistance to soil-borne cereal mosaic virus is not known, but suggests that a gene on 5DL conferring resistance to both viruses may be present in T. aestivum, as well as the D-genome donor Ae. tauschii. 相似文献
7.
Ping-Rong Yuan Hyun-Jung Kim Qiong-Hua Chen Hong-Guang Ju Shi-Dong Ji Sang-Nag Ahn 《Journal of Crop Science and Biotechnology》2010,13(4):205-212
Quantitative trait loci (QTL) associated with four milling recovery properties, two chemical properties, six paste properties
of grain, and six textural parameters of cooked rice were identified using an introgression line (IL) population of rice developed
from an interspecific cross over two years. The IL population consisted of 121 lines from a cross between wild rice (O. rufipogon Griff.) and a japonica cultivar. A total of 28 QTLs were identified for the 14 traits using inter mapping. Of these, 10 were
significant over two years indicating that these QTLs are stable across years and environments. For eight (21%) of the QTLs
identified, the O. rufipogonderived alleles contributed a desirable effect on amylose content, protein content, minimum viscosity, final viscosity, and
consistency. Among these, pc3 for protein content and ac7 for amylose content were significant in both years and showed an R2 value of 25.5 and 30.9%, respectively. The markers closely associated with these useful alleles can be used to trace the
inheritance of specific chromosome segments in the IL population and also offer a starting point for map-based cloning of
genes underlying these traits. 相似文献
8.
C. M. Konik-Rose S. Rahman R. Appels R. Moss G. McMaster D. R. Marshall F. L. Stoddard 《Euphytica》2009,167(2):203-216
Greater variability in starch properties is found in lower ploidy wheats than in commercial hexaploid wheats. This paper reports
on the starch properties and variability in granule bound starch synthase (GBSS) loci of 17 diploid (Aegilops tauschii) and 12 tetraploid (durums) potential progenitors of wheat, compared with 29 synthetic hexaploid wheats produced from such
progenitors. Starch properties examined were granule size distribution, swelling power, amylose content, gelatinisation and
amylose-lipid dissociation properties. A PCR screening method was able to detect the presence or absence of each of the three
GBSS genes. It also detected polymorphisms in eight diploids and nine hexaploids, all displaying the same 25 bases deletion
in the D genome allele of GBSS. Two tetraploids and five hexaploids were null 4A for GBSS. There was little difference in
the amylose contents and amylose-lipid dissociation peak temperatures of the synthetic hexaploids and the lower ploidy wheats.
The synthetic hexaploids showed intermediate swelling power values with the durums giving the highest swelling powers. The
durums also had higher B granule contents than the A. tauschii accessions, but not as high as the synthetics. However, the A. tauschii samples gave the highest gelatinisation peak temperatures. The presence of the null 4A mutation was positively correlated
with swelling power, amylose content and DSC measurements. The new smaller D genome allele of GBSS was associated with slightly
higher swelling power. These results confirm the value of wheat progenitor lines as sources of new starch properties for hexaploid
wheat.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Eighty-two varieties of rice from different regions in Thailand were selected to explore the Waxy (Wx)gene diversity and indica-japonica differentiation of chloroplast DNA. A comparison of the 5 splice site in the first intron was made between glutinous and nonglutinous rice. It revealed that non-glutinous with low-amylose content and glutinous rice were characterized as the Wxb allele based on the G-to-T base substitution, whereas non-glutinous rice with intermediate and high amylose carried the Wxa allele. Four Wx microsatellite alleles, (CT)n repeat, (n = 16,17,18 and 19) were found in glutinous rice. In contrast, non-glutinous rice showed five Wx microsatellite alleles (n = 11, 16, 17, 18 and 19). The (CT)17 allele was prominent allele in Thai population, while the (CT)11 allele was found only in intermediate and high amylose rice varieties from southern Thailand. Almost all of upland rice grown by various ethnic groups in northern Thailand were characterized as japonica type based on their having the PstI-12 fragment in their cpDNA, whereas most of rainfed lowland varieties from other regions of Thailand were indica. This exploration of DNA-based genetic markers is important, as it enhances our ability to describe and manipulate sources of genetic variation for rice breeding programs. 相似文献
10.
This paper describes the relative efficiency of three marker systems, RAPD, ISSR, and AFLP, in terms of fingerprinting 14
rice genotypes consisting of seven temperatejaponica rice cultivars, three indica near-isogenic lines, three indica introgression lines, and one breeding line of japonica type adapted to high-altitude areas of the tropics with cold tolerance genes. Fourteen RAPD, 21 ISSR, and 8 AFLP primers
could produce 970 loci, with the highest average number of loci (92.5) generated by AFLP. Although polymorphic bands in the
genotypes were detected by all marker assays, the AFLP assay discriminated the genotypes effectively with a robust discriminating
power (0.99), followed by ISSR (0.76) and RAPD (0.61). While significant polymorphism was detected among the genotypes of
japonica and indica through analysis of molecular variance (AMOVA), relatively low polymorphism was detected within the genotypes of japonica rice cultivars. The correlation coefficients of similarity were significant for the three marker systems used, but only the
AFLP assay effectively differentiated all tested rice lines. Fingerprinting of backcross-derived resistant progenies using
ISSR and AFLP markers easily detected progenies having a maximum rate of recovery for the recurrent parent genome and suggested
that our fingerprinting approach adopting the ‘undefined-element-amplifying’ DNA marker system is suitable for incorporating
useful alleles from the indica donor genome into the genome of temperate japonica rice cultivars with the least impact of deleterious linkage drag. 相似文献
11.
D. Samsampour B. Maleki Zanjani J. K. Pallavi Anupam Singh A. Charpe S. K. Gupta K. V. Prabhu 《Euphytica》2010,174(3):337-342
The recessive adult plant resistance (APR) gene Lr48 in wheat was tagged with flanking random amplified polymorphic DNA (RAPD) markers. Markers S336775 in coupling and S3450 in repulsion with Lr48 were identified in wheat line CSP44. Tests of these markers on available Thatcher near-isogenic lines (NILs) detected the
likely presence of Lr48 in TcLr25. A test of allelism of APR involving the cross TcLr25 × CSP44 indicated that Lr48 was present in both lines. A separate experiment on inheritance of resistance in an F2 population of TcLr25 × Agra Local confirmed the presence of a dominant seedling resistance gene (Lr25) and a recessive APR gene (Lr48) in TcLr25. This study demonstrated the value of molecular markers in identifying the presence of masked genes in genetic
stocks where direct phenotyping failed to detect their presence. 相似文献
12.
Speltoid spikes are characterized by pyramidal spike morphology featuring an elongated rachis and tenacious glumes. Speltoids
are considered undesirable spike aberrants in wheat breeding leading to increased heterogeneity within a cultivar candidate.
As a consequence, the presence of speltoids may result in rejection of a cultivar candidate during official field trials or
denial of cultivar certification during seed multiplication. A reliable method is, thus, required to assess the occurrence
of speltoids, early on in a wheat breeding program. The domestication gene Q located on the long arm of wheat chromosome 5A is known to suppress the speltoid phenotype in wheat. Here, a quantitative
pyrosequencing assay was developed to distinguish between normal wheat plants, which possess two copies of the Q allele, and aberrants, which are either aneuploids lacking the correct number of chromosome 5A copies or plants which carry
the primitive q allele. An accurate and reproducible determination of the Q gene copy number was achieved for different wheat genotypes based on homoeologous sequence quantification with two primer
combinations at the Q locus. Single plants with one to four copies of the Q allele could be detected by quantitative pyrosequencing which corresponded to the occurrence of speltoid (1 Q allele), normal (2 Q alleles), and compact (more than 2 Q alleles) spikes. Q and q specific alleles could be differentiated at SNP position 2299 of the Q gene. This SNP is assumed to be related to the emergence of free-threshing wheat forms. To our knowledge this is the first
report for detection of aneuploids and differentiation of Q alleles in bread wheat using pyrosequencing technology. In future, quantitative pyrosequencing assay can be applied in wheat
breeding programs to carry out marker-assisted selection against the presence of speltoid spike aberrants. 相似文献
13.
Václav Šíp Jana Chrpová Alžběta Žofajová Kateřina Pánková Martin Užík John W. Snape 《Euphytica》2010,172(2):221-233
Based on studies of the distribution of alleles at the important Rht and Ppd loci on wheat chromosomes 4B, 4D and 2D, different groups of winter wheat cultivars registered in the Czech and Slovak Republics
during the period 1976–2007 were examined for a range of agronomic traits using official data from multi-location trials.
Significant variation for all traits was detected among and between genotype groups. The frequent introduction of ‘Rht-D1b’ cultivars from the UK and Western Europe to the Czech Republic since 1995 has positively influenced lodging resistance and
undoubtedly also yielding ability, but negatively affected winter-hardiness and bread making quality. An improved opportunity
for earlier flowering cultivars with high winter-hardiness levels, in combination with high bread-making quality, can be obtained
with genotypes carrying the Xgwm261 allele 192-bp that is probably indicative of the presence of Rht8. While GA insensitive Rht genes caused approximately a 10 cm reduction of plant height, the 192-bp allele at Xgwm261 was not associated, in these conditions, with a significant reduction in plant height when compared to Xgwm261 alleles 165- and 174-bp. Likewise, the photoperiod insensitive allele Ppd-D1a did not have a significant effect on plant height and it had not adversely affected other characters. Later heading genotypes
carrying Xgwm261 alleles174- and 165-bp, often in combination with Ppd-D1b, could probably guarantee broader adaptability, which is highly desirable for changeable weather conditions. While the presence
of the 192-bp allele was clearly associated with suitability for cultivation in the warmer maize growing regions, this was
not so obvious for Ppd-D1a, particularly when combined with the 174-bp allele. GA responsive genes did not, apparently, influence adaptability to the
different growing conditions. These studies reveal that there were both shortcomings and benefits attributable to the use
of germplasm from different origins when introducing Rht and Ppd alleles. These results should be helpful to breeders in optimizing the choice of parents for crossing, and selection strategy
in these target environments. 相似文献
14.
Lu Xiao Bin Yi Yufeng Chen Zhen Huang Wei Chen Chaozhi Ma Jinxing Tu Tingdong Fu 《Euphytica》2008,164(2):377-384
7–7365AB is a recessive genic male sterile (RGMS) two-type line, which can be applied in a three-line system with the interim-maintainer,
7–7365C. Fertility of this system is controlled by two duplicate dominant epistatic genes (Bn;Ms3 and Bn;Ms4) and one recessive epistatic inhibitor gene (Bn;rf). Therefore an individual with the genotype of Bn;ms3ms3ms4ms4Rf_ exhibits male sterility, whereas, plant with Bn;ms3ms3ms4ms4rfrf shows fertility because homozygosity at the Bn;rf locus (Bn;rfrf) can inhibit the expression of two recessive male sterile genes in homozygous Bn;ms3ms3ms4ms4 plant. A cross of 7–7365A (Bn;ms3ms3ms4ms4RfRf) and 7–7365C (Bn;ms3ms3ms4ms4rfrf) can generate a complete male sterile population served as a mother line with restorer in alternative strips for the multiplication
of hybrid seeds. In the present study, molecular mapping of the Bn;Rf gene was performed in a BC1 population from the cross between 7–7365A and 7–7365C. Bulked segregant analysis (BSA) and amplified fragment length polymorphism
(AFLP) technique was used to identify molecular markers linked to the gene of interest. From a survey of 768 primer combinations,
seven AFLP markers were identified. The closest marker, XM5, was co-segregated with the Bn;Rf locus and successfully converted into a sequence characterized amplified region (SCAR) marker, designated as XSC5. Two flanking
markers, XM3 and XM2, were 0.6 cM and 2.6 cM away from the target gene, respectively. XM1 was subsequently mapped on linkage
group N7 using a doubled-haploid (DH) mapping population derived from the cross Tapidor × Ningyou7, available at IMSORB, UK.
To further confirm the location of the Bn;Rf gene, additional simple sequence repeat (SSR) markers in linkage group N7 from the reference maps were screened in the BC1 population. Two SSR markers, CB10594 and BRMS018, showed polymorphisms in our mapping population. The molecular markers found
in the present study will facilitate the selection of interim-maintainer. 相似文献
15.
Aye Nyein Chan Shutu Xu YaQin Shi YaNan Li Ali Farhan DongWei Guo JiQuan Xue 《Euphytica》2017,213(1):12
Association mapping was conducted to explore favorable alleles of the chlorophyll-related non-yellow coloring 1 (NYC1) gene under light and dark using an association panel of 146 maize inbred lines. A total of 14 polymorphic sites were identified to be significantly associated with at least one of the chlorophyll-related traits at the seedling stage. Four single nucleotide polymorphisms (SNPs) (S320, S2951, S3901, and S3355) from the NYC1 gene were respectively strongly associated with chlorophyll b (chlb), the ratio of chlorophyll a to chlorophyll b (chl_ratio), chlorophyll a degradation (chla_deg), and total chlorophyll degradation (total_chl_deg). SNPs S320 (C/A) in exon 1, and S2951 (A/G) in intron 8 was related to chlb, with 6.01 and 8.89% of phenotypic variation under light treatment, respectively. Under dark treatment, SNP S3901 (C/T), located in 3′ untranslated region (3′UTR), was associated with chl_ratio, explaining 7.01% of the observed phenotypic variation, whereas SNP S3355 (C/G) in intron 9 explained 6.48 and 5.18% of phenotypic variations in chla_deg and total_chl_deg, respectively. Taken together, these results indicated that the NYC1 gene plays an important role in chlorophyll content and other related traits, and different sites act on chlorophyll metabolism under different light intensities in maize seedlings. Furthermore, these findings improve our understanding of the genetic basis of chlorophyll metabolism under different light conditions. 相似文献
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18.
The present study aims at characterization of Jatropha species occurring in India using nuclear and organelle specific primers for supporting interspecific gene transfer. DNA from
34 accessions comprising eight agronomically important species (Jatropha curcas, J. gossypifolia, J. glandulifera, J. integerrima, J. podagrica, J. multifida, J. villosa, J. villosa. var. ramnadensis, J. maheshwarii) and a natural hybrid, J. tanjorensis were subjected to molecular analysis using 200 RAPD, 100 ISSR and 50 organelle specific microsatellite primers from other
angiosperms. The nuclear marker systems revealed high interspecific genetic variation (98.5% polymorphism) corroborating with
the morphological differentiation of the species used in the study. Ten organelle specific microsatellite primers resulted
in single, discrete bands of which three were functional disclosing polymorphism among Jatropha species. The PCR products obtained with organelle specific primers were subjected to sequence analysis. PCR products from
two consensus chloroplast microsatellite primer pairs (ccmp6 and 10) revealed variable number of T and A residues in the intergenic
regions of ORF 77–ORF 82 and rp12–rps19 regions, respectively in Jatropha. Artificial hybrids were produced between J. curcas and all Jatropha species used in the study with the exception of J. podagrica. Characterization of F1 hybrids using polymorphic primers specific to the respective parental species confirmed the hybridity of the interspecific
hybrids. Characterization of both natural and artificially produced hybrids using chloroplast specific markers revealed maternal
inheritance of the markers. While the RAPD and ISSR markers confirmed J. tanjorensis as a natural hybrid between J. gossypifolia and J. curcas, the ccmp primers (ccmp6 and 10) unequivocally established J. gossypifolia as the maternal parent. Evaluation of backcross interspecific derivatives of cross involving J. curcas and J. integerrima indicate scope for prebreeding and genetic enhancement of Jatropha curcas through interspecific hybridization. 相似文献
19.
This study reports the implementation of three strategies for the development of genetic markers and their evaluation in both
progenitors of an F2 population used for the construction of a genetic map of Coffea arabica. The strategies were Cleaved Amplified Polymorphic Sequences (CAPS), Single Strand Conformational Polymorphism (SSCP), and
sequence analysis predicted Single Nucleotide Polymorphism (SNP). The methodologies were developed from different sequence
sources: For CAPS, we used 25 COS sequences derived from Hedyotis spp. and 29 COSII sequences derived from Solanaceae and Rubiaceae species; for SSCP, we used 111 coffee EST sequences, 50 COSII
sequences, and 10 C. arabica BAC end sequences. A low polymorphism was identified with the CAPS and SSCP methodologies. A total of 61 SNPs were identified
in silico from 5,371 ESTs of coffee and from amplified, cloned, and sequenced COSII markers. Sixteen of these SNPs were validated
with Luminex technology and 2 of them were polymorphic in C. arabica genotypes. This study highlights the difficulties of finding polymorphism in the species C. arabica where SNP identification seems to be the best strategy to search for polymorphic markers for this low diversity plant. 相似文献
20.
Moytri RoyChowdhury Yulin Jia Aaron Jackson Melissa H. Jia Robert Fjellstrom Richard D. Cartwright 《Euphytica》2012,184(1):35-46
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