Figure 6.

Grain yield and N use parameters at maturity of two HvGS1‐1 cisgenic lines (T3, 2.2 and 4.5) and wild‐type growing under ambient (400 μL/L, open bars) or elevated (900 μL/L, hatched bars) atmospheric CO₂. (a) Grain yield, (b) straw yield (shoot biomass without grain), (c) grain protein concentration, (d) straw N concentration, (e) total shoot N, (f) thousand kernel weight, (g) nitrogen utilization efficiency (NUE) and (h) nitrogen harvest index (NHI) of plants grown with low (0.2 g N/L soil), high (0.6 g N/L soil) and excessive (1.0 g N/L soil) N supply. Data are presented as means ± SE (n = 6). Asterisks (*) above bars indicate significant difference (P < 0.05, Fischer LSD) between ambient and elevated CO₂ treatment inside each genotype. Levels of significance treatment effects (genotype, N and CO₂ level) and their interactions analysed by ANOVA are shown as * (P < 0.05) and ** (P < 0.01), non‐significant effects are not indicated.