RELATIONSHIP BETWEEN GRAIN-YIELD AND GRAIN NITROGEN CONCENTRATION IN WINTER TRITICALE

Ten hexaploid winter triticale lines were grown for two cropping perio ds at three locations in western Switzerland, Averaged across the six environments, the differences between lines were statistically signifi cant (P = 0.05) for grain yield, above-ground biomass, N uptake, grain N yield, nitrogen harvest index, grain N concentration and straw N co ncentration. There were significant line x environment interactions fo r all traits. Grain yield and grain N concentration were inversely rel ated (r = - 0.74(*)). Diagrams in which grain yields were plotted aga inst grain N concentration were used to identify lines with a consiste ntly unusual combination of grain yield and grain N concentration. Des pite comparable grain yields, Line 3 had a high grain N concentration, while that of Line 7 was low Line 3 was superior to Line 7 in both N uptake and N harvest index. Averaged across environments and lines, th e N harvest index was 0.73 which corresponds to N harvest indices repo rted for bread wheat in the same region. We considered the feasibility of developing triticale lines which would outperform the best recent ones in N uptake and partitioning. However, we doubted that this would bring about a marked increase in grain N concentration, because, in t he long run, the expected genetic progress in grain yield will lead to a dilution of grain protein by grain carbohydrate increments.