1,721,158 research outputs found
Evaluation of Aegilops tauschii Coss. for resistance to wheat stem rust and inheritance of resistance genes in hexaploid wheat
No full textWith the objective to identify new sources of resistance to wheat stem rust, a collection of 169 accessions of Aegilops tauschii, obtained from the IPK genebank at Gatersleben, Germany, were screened for resistance under controlled conditions. Fourteen (8%) accessions were resistant to stem rust among which 10 were highly resistant ( IT 5; and 1) and four exhibited a moderately resistance reaction ( IT 5 2). From the synthetic hexaploids which were produced by hybridizing resistant Ae. tauschii with susceptible Triticum durum, six synthetics expressed a high level of stem rust resistance similar to their corresponding diploid parents, while five displayed either a reduced or complete susceptibility compared to their Ae. tauschii parents. This suppression of resistance at the hexaploid level suggests the presence of suppressor genes in the A and/or B genomes of the T. durum parents. Inheritance of resistance from crosses of five stem rust resistant synthetic hexaploids with two susceptible T. aestivum genotypes revealed that three of the synthetics (syn 101, syn 601 and syn 801) possessed one dominant gene each, syn 111 has two different dominant genes and syn 116 has two complementary interacting genes for stem rust resistance. Intercrosses among the four stem rust resistant synthetic hexaploids indicated that the putative genes conferring stem rust resistance in each of the synthetics are neither allelic nor closely linked to each other
Erhöhte Anfälligkeit von Reben gegenüber Botrytis cinerea nach Begasung mit Schwefeldioxid und Ozon
No full textEffects of field application of tebuconazole on yield, yield components and the mycotoxin content of Fusarium-infected wheat grain
No full textWinter wheat cultivar Basalt was artificially inoculated with Fusarium culmorum at the end of anthesis and treated with the systemic fungicide tebuconazole (Folicur(R)) a few days before and/or after inoculation. Check plots remained uninoculated and unsprayed. Head infections, yield, yield components and the percentage of Fusarium-infected kernels were determined. Artificial Fusarium inoculation lowered yield significantly by 24.2-45.0%. Any fungicide treatment saved yield, thousand grain weight and kernel numbers per head. Pre-infectional application of tebuconazole was superior to application carried out post-infection. Moreover, the fungicide controlled deoxynivalenol (DON) synthesis in the field to a considerable extent, and enabled good control of Fusarium head blight, glume blotch and the percentage of Fusarium-infected kernels. The levels of Fusarium kernel infection after harvest clearly reflected the DON content of wheat grain
Zum Vorkommen der Weißfäule an Importunterlagen und ihrer Bedeutung für die Rebenveredlung
No full textSusceptibility changes of some agricultural plants to fungal pathogens after fumigation in closed chambers
No full textInfluence of different storage conditions on the mycotoxin production and quality of Fusarium-infected wheat grain
No full textWheat seed samples with different initial infection levels of Fusarium culmorum were kept under different storage conditions for 36 weeks. Samples for analysis were drawn before storage and at intervals of 6-8 weeks to determine the mycotoxin contents, seed health and seed quality. Zearalenone (ZEA) accumulated to higher kernel contents towards the end of storage, when the seed was stored under warm and humid conditions [25 degrees C/90% relative humidity (RH)], whereas the deoxynivalenol (DON) content of severely infected kernel samples (> 50%) remained unchanged under any of the conditions. On the other hand, DON contents increased in samples with a slight (4%) or moderate (15%) Fusarium infection level, when the seed was stored under warm and humid conditions. Nivalenol (NIV) was not found in any samples immediately after harvest but later on in storage, and only under cool or warm but very humid conditions (15 degrees C/84% RH and 25 degrees C/90% RH). During storage, the mycotoxin contents of the samples did not reflect the percentage of Fusarium infected kernels. Under warm but dry conditions (25 degrees C/62% RH) the seed germination rate showed a slight increase or remained nearly constant; at the same time the Fusarium infection level of the kernels decreased fairly fast. Cool and dry conditions (15 degrees C/56% RH) maintained good seed quality but the Fusarium infection level of the kernels remained largely the same. Warm and humid conditions are not appropriate to maintaining quality of both seed and grain product
Predisposition of wheat and barley to fungal leaf attack by preinoculative treatment with ozone and sulphur dioxide
No full textOccurrence of Monographella nivalis var. mayor and Fusarium culmorum on barley in Germany in 1992 (Abstract)
No full textSecondary effects of photochemical oxidants on cereals: alterations in susceptibility to fungal leaf diseases
No full textIn a nine-day fumigation experiment with 60–80 ppb ozone and 6–8 ppb PAN (peroxyacetyl-nitrate) predisposition of wheat and barley towards necrotrophic leaf pathogens was enhanced although leaves were not visibly injured by the treatment. Particularly, spot blotch (Drechslera sorokiniana) and tan spot (D. tritici-repentis) on wheat and spot blotch on barley were favoured by either of the two pollutants. The pollutant mixture exerted a highly synergistic action on plant susceptibility. In another experiment, wheat leaf attack by Septoria nodorum was highly correlated with increasing levels of ozone (0, 60, 90 and 120 ppb; 7 days; 7 h per day), applied before inoculation. Net blotch of barley (D. teres) was favoured especially at the lower ozone concentrations and on the older leaves. Results are discussed with respect to the increase of leaf diseases in cereal production since about two decades
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