Browsing by Person "Flath, Kerstin"

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    Infrared Imaging for Plant Protection
    (2005) Hellebrand, Hans Jürgen; Dammer, Karl-Heinz; Beuche, Horst; Herppich, Werner B.; Flath, Kerstin
    Fungi infections, which may cause variations of plants’ surface tem- perature, can be recognised by infrared cameras in the thermal range (MIR: λ = 8-12 μm) under laboratory conditions. In the field, pro- nounced natural temperature variations of several Kelvin within the crop canopy prevent the recognition of infected plants by commercial thermal vision systems as stand-alone solutions. Near infrared cam- eras ( λ = 0.9-1.7 μm) fitted with band-pass filters show different inten- sity distributions of the reflected radiation. The evaluation of the spec- tral intensity relations improves the differentiation. By NIR several im- portant contents (H 2 O, sugars, acids, etc.) of the surface tissue cells are measured, whereas thermography determines the plant transpiration.
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    Infrarotbildverfahren im Pflanzenschutz
    (2005) Hellebrand, Hans Jürgen; Dammer, Karl-Heinz; Beuche, Horst; Herppich, Werner B.; Flath, Kerstin
    Pilzbefall, der Temperaturänderungen der Pflanzenoberflächen nach sich zieht, kann unter Laborbedingungen mittels Infrarotkameras im thermischen Bereich (MIR: λ = 8-12 μm) erkannt werden. Aufgrund der natürlichen Temperaturvariation im Pflanzenbestand bis zu einigen Kelvin können gegenwärtig kommerzielle Wärmebildsysteme als Einzellösung unter Feldbedingungen keine geeigneten Informationen für den Pflanzenschutz bereitstellen. Messungen mit der NIR-Kamera im Wellenlängenbereich λ = 0,9-1,7 μm sowie mit Bandpassfiltern (mit und ohne H2O-Band) ergeben unterschiedliche Intensitätsverteilungen der reflektierten Strahlung. Die Auswertung der spektralen Intensitäts-verhältnisse verbessert die Differenzierung. Mit NIR lassen sich Inhaltsstoffe (insbesondere H2O, aber auch gelöste Zucker und Säuren) der Oberflächengewebe erfassen, mit der Thermografie die Transpirationsrate.
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    Quantitative-genetic evaluation of resistances to five fungal diseases in a large triticale diversity panel (×Triticosecale)
    (2022) Miedaner, Thomas; Flath, Kerstin; Starck, Norbert; Weißmann, Sigrid; Maurer, Hans Peter
    The man-made cereal triticale was fully resistant to the biotrophic diseases powdery mildew, leaf rust, yellow rust, and stem rust from its introduction in Europe in the mid-1970s until about 1990. In the following years, new races that were able to infect at least some triticale genotypes developed in all four pathogen populations, and resistance breeding came into focus. Here, we analyzed 656 winter triticale cultivars from 12 countries for resistance to these biotrophic diseases and Fusarium head blight (FHB) at up to 8 location-year combinations (environments). FHB ratings were corrected for plant height and heading stage by comparing three statistical methods. Significant (p < 0.001) genetic variances were found for all resistances with moderate to high entry-mean heritabilities. All traits showed a normal distribution, with the exception of stem rust, where the ratings were skewed towards resistance. There were no substantial correlations among the five disease resistances (r = −0.04 to 0.26). However, several genotypes were detected with multi-disease resistance with a disease rating below average for all five diseases simultaneously. In future, such genotypes must be selected primarily to cope with future challenges of less pesticide use and global climate change.
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    Studying stem rust and leaf rust resistances of self-fertile rye breeding populations
    (2022) Gruner, Paul; Witzke, Anne; Flath, Kerstin; Eifler, Jakob; Schmiedchen, Brigitta; Schmidt, Malthe; Gordillo, Andres; Siekmann, Dörthe; Fromme, Franz Joachim; Koch, Silvia; Piepho, Hans-Peter; Miedaner, Thomas
    Stem rust (SR) and leaf rust (LR) are currently the two most important rust diseases of cultivated rye in Central Europe and resistant cultivars promise to prevent yield losses caused by those pathogens. To secure long-lasting resistance, ideally pyramided monogenic resistances and race-nonspecific resistances are applied. To find respective genes, we screened six breeding populations and one testcross population for resistance to artificially inoculated SR and naturally occurring LR in multi-environmental field trials. Five populations were genotyped with a 10K SNP marker chip and one with DArTseqTM. In total, ten SR-QTLs were found that caused a reduction of 5–17 percentage points in stem coverage with urediniospores. Four QTLs thereof were mapped to positions of already known SR QTLs. An additional gene at the distal end of chromosome 2R, Pgs3.1, that caused a reduction of 40 percentage points SR infection, was validated. One SR-QTL on chromosome 3R, QTL-SR4, was found in three populations linked with the same marker. Further QTLs at similar positions, but from different populations, were also found on chromosomes 1R, 4R, and 6R. For SR, additionally seedling tests were used to separate between adult-plant and all-stage resistances and a statistical method accounting for the ordinal-scaled seedling test data was used to map seedling resistances. However, only Pgs3.1 could be detected based on seedling test data, even though genetic variance was observed in another population, too. For LR, in three of the populations, two new large-effect loci (Pr7 and Pr8) on chromosomes 1R and 2R were mapped that caused 34 and 21 percentage points reduction in leaf area covered with urediniospores and one new QTL on chromosome 1R causing 9 percentage points reduction.