Selektion der Soja und deren Symbiosepartner auf Kühletoleranz und Effizienz der biologischen Stickstoff-Fixierung

In Central Europe low temperature is limiting soybean growth and biological nitrogen fixation (BNF). The BNF efficiency was shown to increase with bradyrhizobia strains selected for their cold tolerance. Significant bradyrhizobia x soybean variety interactions were reported. Co-inoculation with arbuscular mycorrhiza fungi (AMF) may promote bradyrhizobia and improve plant phosphorus uptake. The aim of this study is to identify (i) bradyrhizobia showing improved nodulation under cool conditions, (ii) bradyrhizobia x soybean variety and (iii) bradyrhizobia x AMF interactions. In 2011 twelve bradyrhizobia inoculants were tested with three soybean (Glycine max [L.]) varieties under three temperature regimes (14/10°C, 16/12°C, 22/20 °C) in a pot trial. In 2012 the five most promising bradyrhizobia were inoculated on twenty soybean varieties and an additional trial testing co-inoculated bradyrhizobia and AMF strains was conducted. A significant bradyrhizobia x temperature interaction was found for the number of nodules per plant and the SPAD values (indirect chlorophyll measurement; p ≤ 0,001). Significant bradyrhizobia x variety interactions were observed (p ≤ 0,01). The present results show that the selection of cold tolerant inoculants is as important as adapted soybean varieties. The efficiency of single bradyrhizobia x soybean variety combinations depends on the temperature regime

Soil quality changes in field trials comparing organic reduced tillage to plough systems across Europe (TILMAN-ORG Session)

Field trials on reduced soil tillage under organic farming conditions across Europe were used to compare the soil quality changes over time. Soil organic carbon fractions, soil carbon stocks and microbial community structure were analysed. Most severe differences between plough and reduced tillage were found in the top ten cm of the soil profile. Differences became less or not significant in deeper layers. Analyses are still ongoing and will only be ready to be presented at the conference

Nature and nurture in children's food preferences

Background: Health professionals identify food provision in the home as a key influence on children's food preferences. In contrast, parents often perceive children's food preferences to be inborn. One explanation for this discrepancy could be that environmental and genetic influences vary by food type. Objective: We assessed genetic and environmental contributions to preferences for a wide variety of foods in a large pediatric twin sample. Design: Data were from Gemini, which is a cohort of UK twins born in 2007. Preferences for 114 foods were assessed by parent-completed questionnaire when children were aged 3 y (n = 2686). Foods tried by >75% of respondents were grouped into protein, vegetables, fruit, dairy, starches, and snacks. Quantitative model-fitting analyses were used to assess genetic and environmental influences for each food group. Results: The genetic influence was higher for vegetables (54%; 95% CI: 47%, 63%), fruit (53%; 95% CI: 45%, 61%), and protein (48%; 95% CI: 40%, 57%) but lower for starches (32%; 95% CI: 26%, 38%), snacks (29%; 95% CI: 24%, 35%), and dairy (27%; 95% CI: 20%, 35%). In contrast, shared-environment effects were higher for snacks (60%; 95% CI: 54%, 65%), starches (57%; 95% CI: 51%, 62%), and dairy (54%; 95% CI: 47%, 60%) and lower for vegetables (35%; 95% CI: 27%, 42%), fruit (35%; 95% CI: 26%, 43%), and protein (37%; 95% CI: 27%, 45%). Nonshared environment effects were small for all foods (11–19%). Conclusions: Both genetic and environmental effects were significant for all food groups, but genetic effects dominated for more nutrient-dense foods (vegetables, fruit, and protein), whereas shared environmental effects dominated for snacks, dairy, and starches. These findings endorse the view of health professionals that the home environment is the main determinant of children's liking for energy-dense foods implicated in excessive weight gain but suggest that parents are also correct by identifying innate differences in liking, particularly for nutrient-dense foods that parents and health educators try to encourage