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

Summary

"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."