Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Disease resistance  (91)
Collection
Keywords
Publisher
  • 1
    ISSN: 1432-2242
    Keywords: Key words Triticum aestivum ; Blumeria graminis f. sp. tritici ; QTL mapping ; Molecular markers ; Disease resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Powdery mildew (Blumeria graminis f. sp. tritici) is one of the most damaging diseases of wheat (Triticum aestivum). The objective of this study was to locate and map a recently identified powdery mildew resistance gene, MlRE, carried by the resistant line RE714 using microsatellites uniformly distributed among the whole genome together with a bulked segregant analysis (BSA). The bulks consisted of individuals with an extreme phenotype taken from a population of 140 F3 families issued from the cross between RE714 (resistant) and Hardi (susceptible). The population had been tested with three powdery mildew isolates at the seedling stage. Qualitative interpretation of the resistance tests located the MlRE gene on the distal part of the long arm of chromosome 6A. A subsequent quantitative interpretation of the resistance permitted us to detect another resistance factor on a linkage group assigned to chromosome 5D, which was constructed with microsatellites for which a polymorphism of intensity between bulks was observed. This quantitative trait locus (QTL) explained 16.8– 25.34% of the total variation. An interaction between both the resistant factor (MlRE and the QTL) was found for only one of the isolates tested. This study shows the advantage of making a quantitative interpretation of resistant tests and that the use of microsatellites combined with BSA is a powerful strategy to locate resistance genes in wheat.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-2242
    Keywords: Key words NBS-LRR ; Disease resistance ; sym genes ; Legume-rhizobia symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Pea (Pisum sativum L.) sequences that are analogous to the conserved nucleotide binding site (NBS) domain found in a number of plant disease resistance genes (R-genes) were cloned. Using redundant oligonucleotide primers and the polymerase chain reaction (PCR), we amplified nine pea sequences and characterised their sequences. The pea R-gene analog (RGA)- deduced amino acid sequences demonstrated significant sequence similarity with known R-gene sequences lodged in public databases. The genomic locations of eight of the pea RGAs were determined by linkage mapping. The eight RGAs identified ten loci that mapped to six linkage groups. In addition, the genomic organization of the RGAs was inferred. Both single-copy and multicopy sequence families were present among the RGAs, and the multicopy families occurred most often as tightly linked clusters of related sequences. Intraspecific copy number variability was observed in three of the RGA sequence families, suggesting that these sequence families are evolving rapidly. The genomic locations of the pea RGAs were compared with the locations of known pea R-genes and sym genes involved in the pea-rhizobia symbiosis. Two pea RGAs mapped in the genomic region containing a pea R-gene, Fw, and four pea RGAs mapped in regions of the genome containing sym genes.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-2242
    Keywords: Keywords Oryza sativa L. ; Gene mapping ; Magna porthe grisea ; Pyricularia grisea ; Disease resistance ; Complete resistance ; Resistance genes ; Pyramiding ; RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A framework linkage map was developed using 284 F10 recombinant inbred lines (RILs) from a ’Lemont’×’Teqing’ rice cultivar cross. Evaluation of a subset of 245 of these RILs with five races of the rice blast pathogen permitted RFLP mapping of three major resistance genes from Teqing and one major gene from Lemont. All mapped genes were found to confer resistance to at least two blast races, but none conferred resistance to all five races evaluated. RFLP mapping showed that the three resistance genes from Teqing, designated Pi-tq5, Pi-tq1 and Pi-tq6, were present on chromosomes 2, 6 and 12, respectively. The resistance gene from Lemont, Pi-lm2, was located on chromosome 11. Pi-tq1 is considered a new gene, based on its reaction to these five races and its unique map location, while the other three genes may be allelic with previously reported genes. Lines with different gene combinations were evaluated for disease reaction in field plots. Some gene combinations showed both direct effects and non-linear interaction. The fact that some of the lines without any of the four tagged genes exhibited useful levels of resistance in the field plots suggests the presence of additional genes or QTLs affecting the blast reaction segregating in this population.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-2242
    Keywords: Key words Bacterial soft rot ; Disease resistance ; Chinese cabbage ; Protoplast fusion ; Brassica rapa ; B. oleracea ; B. napus ; Erwinia carotovora subsp. carotovora
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Erwinia soft rot is a destructive disease of Brassica rapa vegetables. Reliable sources of resistance and control methods are limited, so development of highly resistant breeding lines is desirable. Protoplasts from B. rapa and B. oleracea genotypes selected for resistance to soft rot were fused in order to combine different sources of resistance. Twelve somatic hybrids (synthetic B. napus) were obtained and confirmed by morphology, nuclear DNA content, and RAPD analysis. They were normal looking plants that easily set seeds following self-pollination and backcrossing to B. rapa. Assays of detached leaves or seedlings inoculated in a mist-chamber showed that most somatic hybrids had lower disease severity ratings than the B. rapa fusion partner and a commercial variety of B. napus. Some progeny from selfing or backcrossing of somatic hybrids to B. rapa showed much more resistance than either fusion partner. The offspring populations of the somatic hybrids (F1–S1 and F1–BC1) clearly moved to the resistant direction compared to the parents; the percentage of resistant plants increased from 21% (average of parents) to 36% (F1–S1) and 48% (F1–BC1). These results suggest that it may be possible to obtain highly resistant B. rapa lines by further backcrossing and selection.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 65 (1983), S. 67-71 
    ISSN: 1432-2242
    Keywords: Hordeum vulgare s.l. ; Restoration of CMS fertility ; Fungal pathogens ; Disease resistance ; Polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The associations between seedling reactions to three fungal pathogens (Puccinia hordei, Pyrenophora teres, and Rhynchosporium secalis) or between adult plant reaction to Rh. secalis and the male fertility restoration ability of msml cytoplasm were studied in about 100 accessions of Hordeum spontaneum. Significant differences in the severity of infection between classes of restoration ability were observed with two cultures of P. hordei (751 and 7,649) and with Rh. secalis on adult plants in the field. The cultures 7,432, 751 and 7,649 of P. hordei showed significant positive correlations between infection severity and restoration percentage. The culture 7,620 of P. hordei displayed a significant negative correlation. Rh. secalis (cultures 492A and 531 combined) on seedlings and the natural field infection in the 1978 season showed significant positive correlations. The accession class with the partial restoration ability of 0.1 to 5.0% of the four arbitrary classes (0.0, 0.1–5.0, 5.1–55.0, and 90.1–100%), displayed the lowest mean severity of infection in six of the eleven tests. Some frequently appearing races of these pathogens may operate as selective agents in the maintenance of restoration ability in the original spontaneum populations.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 59 (1981), S. 1-10 
    ISSN: 1432-2242
    Keywords: Vigna radiata ; Vigna mungo ; Blackgram ; Greengram ; Disease resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This review is given on the origin and interrelationship of blackgram and greengram: the symptoms, mode of transmission, and host range of important diseases, namely: mungbean yellow mosaic virus, leaf crinkle virus, leaf curl virus, mosaic mottle virus, Cercospora leaf spot, powdery mildew, root and stem rots, bacterial leaf spot and halo blight. The screening for resistance, sources of resistance, including interspecific hybridization, and induced mutations, as well as the genetics of resistance are treated along with suggestions for future breeding strategies of these crops.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1432-2242
    Keywords: Disease resistance ; Bean anthracnose ; Genetic, physiological variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electrophoresis was used to determine genetic and or biochemical variation, if any, among bean lines resistant and susceptible to anthracnose. This was based on two enzyme systems: peroxisase and esterase. It was revealed that resistant and suceptible plants differed in their band patterns and intensities. Band intensity differences occurred mainly among monomorphic bands with higher intensities expressed by susceptible plants, while band pattern differences were expressed both by resistant and susceptible plants. These differences appeared only at certain stages of development. These stages were identified as 3 and 40 days after emergence and were considered as critical stages for screening purposes. The peroxidase isozyme A5 and the esterase isozyme C1 at 3 days, and the peroxidase band C1 and esterase bands A1 and A2 at 40 days were important because these differences could be used as ‘genetic/biochemical’ markers for screening the population for resistance. Thus, electrophoretic differences could be used as a screening aid and this could save time and effort in breeding programmes. Comparisons between inoculated and non-inoculated leaves of resistant and susceptible lines indicated that infection induced changes in both the amount and kind of peroxidases even before symptoms of the disease appeared. However, there were no specific differences between resistant and susceptible lines, indicating that resistant and susceptible lines responded to infection in the same manner.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-2242
    Keywords: Disease resistance ; Genetic variability ; Plant breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Progenies of barley plants taken at random from generations F8, F13, F23, and F45 of Composite Cross II were tested for reaction to three barley pathogens, Helminthosporium teres, Erysiphe graminis, and Rhynchosporium secalis (four races). The frequency of families resistant to each of the three pathogens (excepting one race of R. secalis) increased from early to later generations. Many families carrying combinations of multiple resistance not observed among the parents were found in the later generations; one-half of the parents were susceptible to all three diseases but only 4% of the families in generation F45 were of this phenotype. The frequency of multiply resistant families also increased sharply over generations. Among the parents the greatest concentration of resistant reactions observed was triple resistance: 14% were triply resistant; none were quadruply resistant; nor were any resistant to all three pathogens. In generation F43 36% of the families were triply resistant, 32% were quadruply resistant and 6% were resistant in five of the six disease reactions. The value of later generations of Composite Cross II for breeding against pathogens thus appears to have been increased by recombination and natural selection. Significant positive correlations were found for resistance to races 40, 61, and 74 of R. secalis whereas correlations between resistance to R. secalis, E. graminis, and H. teres were generally nonsignificant. Use of these multiply resistant genotypes in breeding is thus unlikely to be hindered by negative associations between resistance to the three diseases.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-2242
    Keywords: Prunus persica ; Xanthomonas campestris pv. pruni ; Tissue culture ; Cell selection ; Disease resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Individual callus cultures were initiated from 400 immature embryos of bacterial leaf spot-susceptible ‘Sunhigh’ peach. Each was subjected to several selection cycles of a toxic culture filtrate produced by Xanthomonas campestris pv. pruni, the causal agent of leaf spot of peach. Progressively higher concentrations of the filtrate were used in each cycle. Two calli survived, and two plants were regenerated from each of the surviving calli. Each of the four clones was propagated in vitro and tested for whole plant resistance to X. c. pv. pruni. Results from bioassays on greenhouse-grown plants indicated that two out of the four selected clones were significantly more resistant to X. c. pv. pruni than the parental cv ‘Sunhigh’. In addition, one clone was significantly more resistant than the moderately resistant cv ‘Redhaven’.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-2242
    Keywords: Medicago sativa ; Fusarium oxysporum ; Culture filtrate ; Disease resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary From two lines of Medicago sativa characterized by a high regeneration capability, calli resistant to culture filtrate of Fusarium oxysporum f. sp. medicaginis have been selected. In these calli regeneration capability was greatly reduced and only one plant per callus was recovered. Regenerated plants have been evaluated for resistance to culture filtrate and for in vivo resistance to the pathogen. Three plants out of eight were resistant to the fungus and a high correlation between resistance to culture filtrate and in vivo resistance was observed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...