Wirtschaftlichkeit und Stabilität der ökologischen Winterweizenproduktion mit Composite Cross-Populationen

Diversität im Anbausystem wird vielfach als Schüssel für stabile Erträge und ein resilientes Produktionssystem gesehen. Die evolutionäre Pflanzenzüchtung und der Anbau von genetisch heterogenen Composite Cross-Populationen (CCP) sind ein Ansatz die Diversität zu steigern mit dem Ziel stabilere Erträge zu erwirtschaften. Hierbei besteht ein Trade-off zwischen einem kurzfristig hohen Ertragspotenzial bei Liniensorten und potentiell langfristiger Ertragsstabilität von CCP – auch unter Extrembedingungen. Mit einer Leistungs-Kostenrechnung und stochastischer Simulation werden in diesem Beitrag die Wirtschaftlichkeit und das Produktionsrisiko von CCP mit herkömmlichen Liniensorten verglichen. Die Einzelkostenfreie Leistung (€/ha) der CCP liegt etwa auf dem Niveau ökologisch gezüchteter Sorten bei einer etwas besseren Stabilität. Jedoch sind sie konventionellen Sorten klar unterlegen, was aber auch mit dem Alter und Leistungspotenzial der zur Populationsherstellung verwendeten Elternsorten zusammenhängen kann

Produktionsrisiko im ökologischen Winterweizenanbau – Composite Cross-Populationen vs. Liniensorten

Diversität im Anbausystem wird vielfach als Schüssel für stabile Erträge und ein resilientes Produktionssystem gesehen. Die evolutionäre Pflanzenzüchtung und der Anbau von genetisch stark heterogenen Composite Cross Populationen (CCP) sind ein Ansatz die Diversität zu steigern mit dem Ziel stabilere Erträge zu erwirtschaften. Ein Trade-off besteht allerdings zwischen einem kurzfristig hohen Ertragspotenzial bei Liniensorten und potentiell langfristiger Ertragsstabilität von CCP – auch unter Extrembedingungen. Mit einer Leistungs-Kostenrechnung und einem stochastischen Ansatz (Monte Carlo Simulation) werden in dieser Studie die Leistung und das Produktionsrisiko von CCP mit herkömmlichen Liniensorten verglichen. Die CCP zeigten eine relativ geringe Streuung der Ergebnisse. Insbesondere das Risikoprofil der CCP YQII dominierte im Szenario mit N-Düngung 5 der Referenzsorten

Heterogeneous Populations Vs. Pure Line Varieties For Organic Winter Wheat Production In Germany - Production Risk

"Heterogeneous composite cross populations (CCP) may enable winter wheat producers to cope with increasing biotic and abiotic pressure due to climate change. An economic farm model based on a cost benefit analysis was established to compare net return and production risk of organic winter wheat production with CCP and pure line varieties. Two CCPs with both yield- and quality-oriented parent varieties (YQI and YQII ) are compared with ten reference varieties (4 conventional cultivars, 4 from organic breeders, 1 hybrid, 1 feed wheat). The organic production system was modelled with a stochastic approach (Monte Carlo simulation) based on trial data, market prices and standard data. Using iterative simulations (20,000 model calculations), possible results of the target variables were calculated according to the probability distributions of the individual input parameters. Yield distributions were estimated from trial data from the INSUSFAR project (2016 and 2017) using maximum likelihood statistics. Discrete distributions were defined for machinery and labor costs. The individual results of this stochastic simulation can be presented cumulatively as a curve with the corresponding probabilities of occurrence, the risk profile. Risk profiles were used to compare the agronomic options. The evaluation of risk profiles was based on the concept of stochastic dominance. The populations showed a high stability with a moderate economic performance (net return; €/ha). The conventional cultivar 'Achat' dominates the CCP YQI (1st order stochastic dominance) and so do 'Hybery', 'Elixer' and 'Kerubino'. The varieties 'Genius' and 'Poesie' as well as 'Capo' showed a higher net return but also a higher variance and therefore lower stability. Without knowledge of the individual risk-benefit function of decision makers, no recommendation can be given here. The organic varieties 'Butaro' and 'Wiwa' are dominated by the CCP with 2nd order stochastic dominance. If risk neutrality or aversion is assumed, CCPs are preferable here. Both CCPs showed a relatively low variance of results. CCP YQII dominated half of the reference varieties in the N-fertilization treatment. Especially in the scenario with N-fertilization a trade-off between stability and yield was observed. The hybrid variety 'Hybery' and the feed variety 'Elixer' had a high net return and therefore, despite higher variance, dominated the other varieties and the two CCPs.

Heterogeneous Populations Vs. Pure Line Varieties For Organic Winter Wheat Production In Germany - Economic Performance

The economic performance of composite cross populations (CCP) of winter wheat were calculated and compared with pure line varieties using cost benefit accounting. An organic production system was modelled based on field trial data (yield, quality), market information (prices) and standard data (machinery and labor costs) to calculate the net return of the winter wheat production. This paper compares two CCPs created from both yield- and quality-oriented parent varieties (YQI and YQII ) with ten reference varieties. Yield distributions were estimated from experimental data from the INSUSFAR project (harvest years 2016-2019). Simulations for one fertilization scenario (100 kg N) are presented here. At the field trial site, the CCPs were productively and economically similarly successful as or better than reference varieties from organic breeding, with the CCP YQII having the highest net return behind the hybrid and fodder varieties and two of the conventional E-varieties. As expected, these results fit in with previous studies on yield stability by Weedon and Finckh (2019). Our results suggest that the CCPs can also compete (e.g. ‘Capo’) and outperform (e.g. ‘Kerubino’) individual varieties from conventional breeding. However, these calculations are based on one trial location, so that further investigations are necessary in order to make general statements. An economic performance at the same level as or better than popular varieties from organic breeding indicates CCPs competitiveness under low-input conditions

Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029 (syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041 (syst.). The Coulomb correction was found to increase the \lambda_3 value by \~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of 0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.

A Measurement of Rb using a Double Tagging Method

The fraction of Z to bbbar events in hadronic Z decays has been measured by the OPAL experiment using the data collected at LEP between 1992 and 1995. The Z to bbbar decays were tagged using displaced secondary vertices, and high momentum electrons and muons. Systematic uncertainties were reduced by measuring the b-tagging efficiency using a double tagging technique. Efficiency correlations between opposite hemispheres of an event are small, and are well understood through comparisons between real and simulated data samples. A value of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is statistical and the second systematic. The uncertainty on Rc, the fraction of Z to ccbar events in hadronic Z decays, is not included in the errors. The dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the deviation of Rc from the value 0.172 predicted by the Standard Model. The result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European Physical Journal

First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

Measurement of the B+ and B-0 lifetimes and search for CP(T) violation using reconstructed secondary vertices

The lifetimes of the B+ and B-0 mesons, and their ratio, have been measured in the OPAL experiment using 2.4 million hadronic Z(0) decays recorded at LEP. Z(0) --> b (b) over bar decays were tagged using displaced secondary vertices and high momentum electrons and muons. The lifetimes were then measured using well-reconstructed charged and neutral secondary vertices selected in this tagged data sample. The results aretau(B+) = 1.643 +/- 0.037 +/- 0.025 pstau(Bo) = 1.523 +/- 0.057 +/- 0.053 pstau(B+)/tau(Bo) = 1.079 +/- 0.064 +/- 0.041,where in each case the first error is statistical and the second systematic.A larger data sample of 3.1 million hadronic Z(o) decays has been used to search for CP and CPT violating effects by comparison of inclusive b and (b) over bar hadron decays, No evidence fur such effects is seen. The CP violation parameter Re(epsilon(B)) is measured to be Re(epsilon(B)) = 0.001 +/- 0.014 +/- 0.003and the fractional difference between b and (b) over bar hadron lifetimes is measured to(Delta tau/tau)(b) = tau(b hadron) - tau((b) over bar hadron)/tau(average) = -0.001 +/- 0.012 +/- 0.008

Search for Higgs Bosons in e+e- Collisions at 183 GeV

The data collected by the OPAL experiment at sqrts=183 GeV were used to search for Higgs bosons which are predicted by the Standard Model and various extensions, such as general models with two Higgs field doublets and the Minimal Supersymmetric Standard Model (MSSM). The data correspond to an integrated luminosity of approximately 54pb-1. None of the searches for neutral and charged Higgs bosons have revealed an excess of events beyond the expected background. This negative outcome, in combination with similar results from searches at lower energies, leads to new limits for the Higgs boson masses and other model parameters. In particular, the 95% confidence level lower limit for the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA > 72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM parameter space are also considered.Comment: 49 pages. LaTeX, including 33 eps figures, submitted to European Physical Journal