Vårvetesorters effektivitet i användningen av kväve under den huvudsakliga tillväxtperioden

Sammanfattning: Crop efficiency in utilizing available nutrients is an important factor in increasing produc-tivity and reducing the environmental impact of agriculture. Nitrogen is the nutrient that plants need in the largest quantity and wheat, along with maize and rice, is the world's most cultivated crop. In this work, the Nitrogen Use Efficiency, NUE, during the major growth period, HTP, of twelve different spring wheat varieties, were examined. The NUE was calculated as the product of uptake efficiency of nitrogen, UN, and the conversion effi-ciency of nitrogen to biomass, EN. The purpose of this work was to find if there are varietal differences in NUE and its components among the twelve varieties and to link a high NUE to specific characteristics of the varieties. An experiment was performed in a climate chamber with the varieties Dalarna, Vårpärlvete, Kolben, Rubin, Diamant, Progress, Rival, Drott, Prins, Dragon, Dacke and Vinjett. The varieties were arranged randomly in com-plete blocks with four replications. There were two sets of each variety in each replicate as two destructive harvests were carried out. The effect of the properties biomass increase during HTP, chlorophyll content of leaves, specific leaf area and specific root length on NUE, and its components, in spring wheat were studied. Significant differences among varieties were found in the properties biomass growth during HTP, chlorophyll content of leaves and specific leaf area. The results showed that the biomass growth during HTP posi-tively correlated with NUE and its component UN. High biomass growth resulted in good nitrogen utilization. There was however, no clear correlation between biomass growth and EN. The results showed no correlation between chlorophyll content, and NUE or its com-ponents. Varieties with large specific leaf area e.g. Dalarna, in general had a higher NUE than varieties with small specific leaf area e.g. Progress. Related varieties had similar cha-racteristics.