There was a highly significant (P < 0.001) effect of N on yield, with yield increasing as N increased. There were no significant interactions between Selleck SB203580 N and other factors. There was a highly significant (P < 0.001) effect of variety on harvest index, with Baxter (0.39) having a lower harvest index than HM (0.43) or Ellison (0.44). The effects of other factors and interactions on harvest index were not significant. In 2007, vegetative biomass was significantly (P < 0.001) higher in Ellison than in H45 ( Fig. 4). Fungicide had no

effect on biomass of H45. Increasing nitrogen significantly (P < 0.01) increased biomass. Yield of Ellison was higher than that of H45 (Fig. 5). Yield of H45 was significantly (P < 0.001) increased by fungicide treatment.

Nitrogen application significantly (P < 0.001) increased yield. Harvest index was significantly (P < 0.001) higher in H45 with Epacadostat molecular weight fungicide (0.45) than in H45 without fungicide (0.41) or Ellison (0.41). There were no effects of N or interactions on harvest index. In 2006, there was a significant (P < 0.001) effect of nitrogen on grain protein content (GPC). GPC increased with increasing N, but with little difference between 200 and 300 kg ha− 1 rates of N application ( Fig. 6). There was a significant (P < 0.05) variety-by-fungicide interaction, with GPC in HM being increased from a mean of 11.2% to 11.7% by fungicide treatment. In 2007, fungicide had no significant effect on GPC in H45 (Fig. 7). There was a significant interaction between N rate and variety, with the increase in GPC with N being slightly

greater in Ellison than H45. The effect of stripe rust on the ability of the plant to make use of added N was determined by calculating the amount of N in the grain protein per hectare for the susceptible variety in each year. The Mitscherlich (exponential diminishing returns) equation gave significant fits to the response of this parameter to N application rates (Table 1). In both years, fungicide treatment increased the predicted maximum grain N yield by 15–20%. In 2006, fungicide Tolmetin also increased the responsiveness of HM to added N. The fitted curves were used to predict how much N would be returned in grain protein for each unit of N added as fertiliser (Fig. 8). In 2006, the proportion of fertiliser N returned as grain N was much lower in the no-fungicide treatment at all levels of N. In 2007, there was no appreciable difference in N return between fungicide and no-fungicide treatments at low levels of N, with slightly higher N return in the fungicide treatment at N levels above 200 kg ha− 1. Only in the varieties HM and H45, which were susceptible to the dominant stripe rust pathotype present at the time of the field measurements, did fungicide treatment show a significant effect on any of the parameters measured. Stripe rust was also the only foliar disease seen in the plots.