Increase in dry matter content of above-ground biomass under a water supply. Values taken from Beale and Long (1999) (1); Ercoli et al. (1999) (2); Cadoux et al. (2008) (3) and Cosentino et al. (2007) (4). The more marked difference in France was due to an interaction with nitrogen supply, where available, errors bars indicate LSD (P60.05).