Browsing by Person "Oberforster, Michael"

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Ergot infection in winter rye hybrids shows differential contribution of male and female genotypes and environment
(2020) Kodisch, Anna; Wilde, Peer; Schmiedchen, Brigitta; Fromme, Franz-Joachim; Rodemann, Bernd; Tratwal, Anna; Oberforster, Michael; Wieser, Franz; Schiemann, Andrea; Jørgensen, Lise Nistrup; Miedaner, Thomas
Contamination of ergot (Claviceps purpurea) in grains continues to be a problem in outcrossing plants like rye, especially in years of favorable infection (cold, rainy) conditions. The problem is not the yield loss, but the contamination of the grains by toxic alkaloids leading to strict critical values within the European Union. This study was conducted to (1) partition the variation of genotype, inoculation treatments and environment for ergot infection of 12 winter rye genotypes, (2) the effect of varying proportions of a non-adapted restorer gene on ergot, and to (3) reveal within the genotype the relative importance of male pollen fertility and female receptivity on the ergot reaction of single crosses bearing different restorer genes. In total, 12 rye genotypes and two factorial crossing designs with each of five female and four male lines differing in their restorer genes were tested by artificial infection in up to 16 environments in four European countries. High and significant genotypic variation regarding the ergot severity and pollen-fertility restoration were observed. Furthermore significant general combining ability and specific combining ability variances and interactions with environment were obtained. The pollen-fertility restoration of the male had by far the highest importance for ergot severity, the female component, however, also revealed a significant effect. In conclusion, selecting for superior restoration ability is the most promising way on the short term, but there are also possibilities to improve the maternal site in future breeding programs.
The importance of Fusarium head blight resistance in the cereal breeding industry: Case studies from Germany and Austria
(2023) Miedaner, Thomas; Flamm, Clemens; Oberforster, Michael
Fusarium head blight (FHB) resistance in wheat and triticale has a high priority in the European Union because of the strict guidelines for the major mycotoxins deoxynivalenol (DON) and zearalenone (ZON) and the admission policy of the regulatory authorities. Potentially 70% of the arable land in Germany and about 60% in Austria can be affected by Fusarium. Although epidemics occur only in some years and/or some regions, DON and ZON are detected every year in varying amounts in wheat, rye and maize. Despite a high significance of FHB resistance in breeding companies, as validated by a recent survey, breeding progress in wheat is basically absent for FHB resistance in both countries. The main reasons are the complex inheritance of FHB resistance and the high proportions of the dwarfing allele Rht‐D1b in high‐yielding varieties promoting susceptibility. Despite this, some varieties with high FHB resistance (score 2–3 on the 1–9 scale) have been released that account, however, only for 11% and 18% of the multiplication area in Germany and Austria, respectively. For triticale, an official testing system for FHB resistance in terms of DON content exists in Germany and Austria, but not for the other cereals. Susceptibility to maize ear rot has been described in Austria, but not in Germany. Additionally, a testing system for stalk rot resistance in both countries should be established.
Maternal differences for the reaction to ergot in unfertilized hybrid rye (Secale cereale)
(2022) Kodisch, Anna; Schmiedchen, Brigitta; Eifler, Jakob; Gordillo, Andres; Siekmann, Dörthe; Fromme, Franz Joachim; Oberforster, Michael; Miedaner, Thomas
Claviceps purpurea causing ergot maintains to be a problem in commercial cytoplasmic male sterile (CMS)-based hybrid rye growing. The fungal spores compete with pollen during flowering and ergot incidence is reduced in highly pollen-shedding stands. This study was carried out to identify maternal differences in ergot infection in the absence of pollen. Ten male-sterile single crosses were tested by needle and spray inoculation and kept unfertilized in up to four field sites (Germany, Austria) and three greenhouse experiments, respectively, in two years. A medium to high correlation was observed between field (needle inoculation) and greenhouse (spray inoculation) experiments. The environments (=location × year combinations) differed in their ergot severity and ergot incidence. Significant ( P ≤ 0.05) genotypic and genotype × environment interaction variances were detected for the unfertilized male-sterile single crosses in both test systems for both traits. The single cross K_4 showed a significantly lower ergot severity averaged across all environments, thus being more resilient to ergot than the other genotypes. In conclusion, spray and needle inoculation are suitable for testing unfertilized male-sterile rye materials, testing across several environments (locations, years) is definitely necessary. Selection of specific females might give the potential for further reducing ergot contamination in hybrid rye in future. The frequency of such genotypes within larger breeding populations needs to be analyzed.