Contrasting performance of barley and wheat in a wide range of conditions in Mediterranean Catalonia (Spain)

Despite that the idea of better yield adaptation to low‐yielding conditions of barley than wheat is widespread, there have been few efforts in directly comparing their performance in Mediterranean conditions. We compared wheat and barley regional yields in 41 counties of Catalonia for the period 1992–2004. No differences were clear, particularly at low‐yielding conditions, with a trend for a better wheat performance in relatively high‐yielding environments. We then conducted field experiments during two consecutive seasons, sowing wheat and barley with six levels of nitrogen fertilisation under rainfed conditions (2003–04, experiment I) and two levels of nitrogen fertilisation and two water regimes (rainfed and irrigated) in 2004–05 (experiment II). In experiment I, wheat outyielded barley in treatments that received no N fertiliser (4.58 and 3.60 Mg ha^?1, respectively) indicating that the higher yield potential of wheat was associated with better performance in a condition of relatively low yield. In experiment II, wheat and barley yields were found not to be significantly different across all treatments (2.86 and 2.62 Mg ha^?1, respectively) or in the lowest yielding treatments (1.40 and 1.07 Mg ha^?1, respectively). Therefore, it seems that it may not be universally accepted that under Mediterranean conditions barley would unequivocally behave better than wheat.