To examine barley germplasm management interaction

• All cultivars gave their highest yield under higher fungicide and nitrogen input (High input management), but cultivars differed in their response to increasing input with Westminster being the least responsive (1.69t/ha increase from low to high input) and Oxford the most responsive (3.09t/ha).
• RGT Planet was the highest yielding cultivar, although its advantage over Westminster was only apparent at higher levels of input, under low input both yielded similarly.
• Disease control resulting from the later fungicide application at GS37 and GS59 was strongly implicated in the yield differences, particularly between low and standard input where there was no difference in N input.
• Disease (net form of net blotch) in Oxford was uncontrollable in this trial even under high input where yield was maximised.
• RGT Planet, RGT Conquest and Westminster showed no significant difference in grain protein across the three management levels, whilst the proteins of Granger and Oxford decreased as yield increased from low to high input.
• Granger and RGT Planet recorded the lowest grain screenings. There was no significant effect of management level on screenings with these two cultivars or Westminster.
• In contrast, Oxford and Conquest that gave the largest responses to higher input showed significant decreases in grain screenings as input was increased.
• The devastating effect of NFNB on Oxford in this HRZ environment was very evident in both yield and screening results. As later fungicide input was removed from the management program so was the yield with significant reductions in yield and increased screenings.
• Under the lowest input RGT Planet and Westminster were significantly higher yielding than other cultivars tested.
• Under the highest input RGT Planet was significantly higher yielding than all other cultivars tested and produced the highest gross margins at each management level.
• With the very high disease pressure in this trial, the higher fungicide input associated with the High Input management made this the most cost effective management program of the Crop Technology Centre trials.
• As a result of higher disease pressure unlike wheat (Protocol 1) higher inputs of fungicide were generally more cost effective in barley sown early, irrespective of cultivar.