Resistenzzüchtung für den Ökologischen Landbau bei Getreide

Fazit Auch im Ökologischen Landbau gibt es Forschungsbedarf für Resistenzzüchtung, die Schwerpunkte sind aber teilweise andere als im konventionellen Bereich. Bei Ährenfusariosen kann der Ökologische Landbau die vielfältigen Bestrebungen der konventionellen Züchter nutzen, in dem er die Resistenz bei der Sortenwahl berücksichtigt. Bereits mittelanfällige Sorten könnten hier einen ausreichenden Schutz bieten. Bei Mutterkorn ist dringender Handlungsbedarf bei Roggen geboten, da hier mit Kulturmaßnahmen wenig Fortschritte zu erzielen sind. Die genetischen Unterschiede lassen gute Selektionsmöglichkeiten erwarten. Bei Triticale scheint aufgrund der bisherigen Ergebnisse wegen des geringen Befalls keine Züchtung erforderlich zu sein. Anders sieht es bei den Brandkrankheiten des Weizens aus. Wenn die Saatgutproduktion ganz oder teilweise unter ökologischen Bedingungen stattfinden soll, kann es zunehmend zu Problemen kommen, brandfreies Z-Saatgut zu produzieren. Dies zeigen die Erfahrungen aus Osteuropa, wo aus wirtschaftlichen Gründen kaum noch gebeizt wird und die Brandpilze als Schadursache rasch wieder oberste Priorität erlangt haben

Züchtungsforschung für den Ökologischen Landbau an der Landessaatzuchtanstalt Hohenheim – Roggen, Triticale und Sonnenblumen

Breeding is an important tool to develop varieties with an optimal adaptation to organic farming. Several important traits are not covered by conventional research and breeding. At the State Plant Breeding Institute we are presently working on (1) resistance of rye to ergot (Claviceps purpurea), (2) nitrogen(N)-use efficiency in triticale, and (3) protein content of sunflower. The inheritance of these complex traits is quantitative. They are analysed in replicated field experiments at two locations in three years at several organic farms in Germany. For testing ergot resistance in rye, 68 populations, 250 full-sib families, 64 lines, and their 90 testcrosses were inoculated at mid-flowering by a spore suspension. All four material groups displayed significant (P<0.01) genotypic variation, indicating that a resistance selection should be feasible. N-use efficiency of 64 triticale genotypes was evaluated at two different N-levels. Significant genotypic variation was found, which is a prerequisite for breeding for improved N-use efficiency. To increase protein content, the 230 sunflower inbred lines investigated showed a high variation for protein and oil content. Only a small negative correlation between both traits was found. Thus, it should be possible to breed lines with high protein and high oil contents

Verminderung von Alkaloiden in der Nahrungskette durch die züchterische Verbesserung der Mutterkorn-Resistenz von Winterroggen

Rye as an outcrossing crop is highly susceptible to ergot infection caused by Claviceps purpurea. It is ecologically the best solution to avoid the infection already in the field by growing resistant varieties. Aim of our study is the analysis of inheritance of self-fertile rye material for ergot resistance and alcaloid content. Sixty CMS inbred lines and their 90 CMS crosses were tested in pollen-isolated fields in three environ-ments under the conditions of Ecological Farming by artificial inoculation. The sclerotia weight per head was evaluated as resistance trait. Both, CMS lines and testcrosses showed significant genotypic differences at the individual environments. Correlation between both groups was significant (r=0,6-0,7; P=0,01). The alcaloid contents and the alcaloid spectra of 25 CMS lines revealed no genotypic difference. Breeding of self-fertile rye for a higher resistance to ergot should be successful on the long run

Optical-pump terahertz-probe spectroscopy in high magnetic fields with kHz single-shot detection

We demonstrate optical pump/THz probe (OPTP) spectroscopy with a variable external magnetic field (0-9 T) in which the time-dependent THz signal is measured by echelon-based single-shot detection at a 1 kHz repetition rate. The method reduces data acquisition times by more than an order of magnitude compared to conventional electro-optic sampling using a scanning delay stage. The approach illustrates the wide applicability of the single-shot measurement approach to nonequilibrium systems that are studied through OPTP spectroscopy, especially in cases where parameters such as magnetic field strength (B) or other experimental parameters are varied. We demonstrate the capabilities of our measurement by performing cyclotron resonance experiments in bulk silicon, where we observe B-field dependent carrier relaxation and distinct relaxation rates for different carrier types. We use a pair of economical linear array detectors to measure 500 time points on each shot, offering equivalent performance to camera-based detection with possibilities for higher repetition rates

Multi-parental QTL mapping of resistance to white spot of maize (Zea mays) in southern Brazil and relationship to QTLs of other foliar diseases

Maize white spot (MWS) is one of the most important foliar diseases in Brazil causing significant yield losses. Breeding genotypes with MWS resistance is the most sustainable alternative for managing such losses; however, their genetic control is poorly understood. Our objectives were to identify genomic regions controlling MWS resistance and to explore the presence of common regions controlling resistance to MWS, grey leaf spot (GLS) and northern corn leaf blight (NCLB). We performed a multi-parental QTL mapping for MWS and GLS resistance with a total of 474 testcrosses and phenotypic data collected in southern Brazil. Six QTLs for MWS resistance on bins 1.03, 1.04, 6.02, 8.05, 1.03, and 10.06 were detected. These findings were compared with previously reported QTLs for NCLB in the same populations, and a common QTL region (bin 8.05) controlling MWS and NCLB resistances was identified. Our findings contribute to a better understanding of MWS resistance by revealing three QTLs (bin 6.02, 1.03, and 10.06), to the best of our knowledge, not yet described in the literature, that are valuable for improving MWS resistance and one promising candidate region for multiple disease resistance.Fil: Kistner, María Belén. Universidad de Hohenheim; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: Galiano Carneiro, Ana Luísa. Kleinwanzlebener Saatzucht; Alemania. Universidad de Hohenheim; AlemaniaFil: Kessel, Bettina. Kleinwanzlebener Saatzucht; AlemaniaFil: Presterl, Thomas. Kleinwanzlebener Saatzucht; AlemaniaFil: Miedaner, Thomas. Universidad de Hohenheim; Alemani

Boundaries of Focus and Volume: An Empirical Study in Neonatal Intensive Care

Our study contributes to the scholarly debate whether organizational units should have a narrow focus and admit a homogeneous patient cluster or whether they should admit a pool of patient clusters. We investigate whether the benefits of increased volume through pooling patients outweigh the disadvantages of increased heterogeneity and pursue our analysis in the context of neonatal care. Our empirical studies relies on 4020 patient episodes collected in 18 German neonatal intensive care units and we distinguish between two patient clusters that differ with respect to the inherent medical risk and operational heterogeneity. Cluster 1 consists of very-low birth weight (VLBW) infants with increased risk of complications but similar service trajectories and lower operational heterogeneity. Cluster 2 contains non-VLBW infants with lower risk of complications but more diversity in disease patterns and higher operational heterogeneity. Our analysis shows that cluster volume, that is, the unit's absolute patient volume in a cluster, is positively related to process outcomes as indicated by decreasing length of stay. This relationship is found for both clusters. Regarding focus, we do not find any evidence of positive effects. In fact, we even find that cluster focus, that is, the unit's relative volume of the cluster, is detrimentally related to process outcomes for non-VLBW patients with lower risk of complications and more operational heterogeneity. This indicates that organizational units providing services for complex patients should not have a narrow focus, but should rather provide services for related patient clusters in order to achieve higher volume levels within the unit

Genomics-assisted breeding for quantitative disease resistances in small-grain cereals and maize

Generating genomics-driven knowledge opens a way to accelerate the resistance breeding process by family or population mapping and genomic selection. Important prerequisites are large populations that are genomically analyzed by medium- to high-density marker arrays and extensive phenotyping across locations and years of the same populations. The latter is important to train a genomic model that is used to predict genomic estimated breeding values of phenotypically untested genotypes. After reviewing the specific features of quantitative resistances and the basic genomic techniques, the possibilities for genomics-assisted breeding are evaluated for six pathosystems with hemi-biotrophic fungi: Small-grain cereals/Fusarium head blight (FHB), wheat/Septoria tritici blotch (STB) and Septoria nodorum blotch (SNB), maize/Gibberella ear rot (GER) and Fusarium ear rot (FER), maize/Northern corn leaf blight (NCLB). Typically, all quantitative disease resistances are caused by hundreds of QTL scattered across the whole genome, but often available in hotspots as exemplified for NCLB resistance in maize. Because all crops are su ering from many diseases, multi-disease resistance (MDR) is an attractive aim that can be selected by specific MDR QTL. Finally, the integration of genomic data in the breeding process for introgression of genetic resources and for the improvement within elite materials is discussed.Generar conocimiento impulsado por la genómica abre una manera de acelerar la reproducción de resistencias proceso por mapeo de familias o poblaciones y selección genómica. Los requisitos previos importantes son grandes poblaciones que se analizan genómicamente mediante matrices de marcadores de densidad media a alta y extensas fenotipado en ubicaciones y años de las mismas poblaciones. Esto último es importante para capacitar a un modelo genómico que se utiliza para predecir valores genómicos estimados de reproducción de fenotípicamente no probados genotipos. Después de revisar las características específicas de las resistencias cuantitativas y las características genómicas básicas técnicas, las posibilidades de reproducción asistida por genómica se evalúan para seis patosistemas con hongos hemi-biotróficos: cereales de grano pequeño / tizón de la cabeza por Fusarium (FHB), trigo / mancha de Septoria tritici (STB) y la mancha de Septoria nodorum (SNB), pudrición de la mazorca de maíz / Gibberella (GER) y pudrición de la mazorca por Fusarium (FER), maíz / tizón de la hoja del maíz del norte (NCLB). Por lo general, todas las resistencias cuantitativas a las enfermedades son causadas por cientos de QTL esparcidos por todo el genoma, pero a menudo disponibles en hotspots como se ejemplifica para Resistencia a NCLB en maíz. Debido a que todos los cultivos padecen muchas enfermedades, la resistencia a múltiples enfermedades (MDR) es un objetivo atractivo que puede seleccionarse mediante MDR QTL específico. Finalmente, la integración de datos genómicos en el proceso de mejoramiento para la introgresión de recursos genéticos y para la mejora.Estación Experimental Agropecuaria PergaminoFil: Miedaner, Thomas. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Galiano-Carneiro Boeven, Ana Luisa. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Galiano-Carneiro Boeven, Ana Luisa. Kleinwanzlebener Saatzucht (KWS) SAAT SE & Co. KGaA; AlemaniaFil: Sewodor Gaikpa, David. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Kistner, Maria Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino; ArgentinaFil: Kistner, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kistner, María Belén. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Grote, Cathérine Pauline. University of Hohenheim. State Plant Breeding Institute; Alemani

Multi-parent QTL mapping reveals stable QTL conferring resistance to Gibberella ear rot in maize

Maize production is on risk by Gibberella ear rot (GER) caused by Fusarium graminearum. This is one of the most important ear rot diseases in temperate zones as it leads to yield losses and production of harmful mycotoxins. We investigated, for the first time, the potential use of Brazilian tropical maize to increase resistance levels to GER in temperate European flint germplasm by analyzing six interconnected biparental populations. We assessed GER symptoms in Brazil and in Europe in up to six environments (= location × year combinations) during the growing seasons of 2018 and 2019. We conducted multi-parent QTL and biparental QTL mapping, and identified four QTLs with additive gene action, each explaining 5.4 to 21.8% of the total genotypic variance for GER resistance. Among them, QTL q1 was stable across test environments, populations, and between inbred lines and testcrosses. The accuracies of genomic prediction ranged from 0.50 to 0.59 depending on the resistance donor and prediction model. Jointly, our study reveals the potential use of Brazilian resistance sources to increase GER resistance levels by genomics-assisted breeding.EEA PergaminoFil: Galiano-Carneiro, Ana L. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Galiano-Carneiro, Ana L. Kleinwanzlebener Saatzucht (KWS) SAAT SE & Co. KGaA; AlemaniaFil: Kessel, Bettina. Kleinwanzlebener Saatzucht (KWS) SAAT SE & Co. KGaA; AlemaniaFil: Presterl, Thomas. Kleinwanzlebener Saatzucht (KWS) SAAT SE & Co. KGaA; AlemaniaFil: Gaikpa, David Sewordor. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Kistner, María Belén. University of Hohenheim. State Plant Breeding Institute; AlemaniaFil: Kistner, María Belén. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Departamento de Maíz; ArgentinaFil: Kistner, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miedaner, Thomas. University of Hohenheim. State Plant Breeding Institute; Alemani