Accumulation of biomass, physiological characteristics and grain yield of bean cultivars under irrigated and dry regimes

In a field experiment, the vegetative growth and the grain yield of four co mmon bean (Phaseolus vulgaris L.) cultivars were evaluated under irrigated or rainfed conditions, corresponding to total water levels of 252 and 123 m m, respectively. Leaf area and shoot biomass were weekly measured. The wate r stress reduced the shoot biomass, the leaf area index and the crop growth rate of al I cultivars. There was no significant difference between cultiv ars in grain yield under rainfed; however, the water stress reduced grain y ield in cultivars, except for Negro Argel. The number of pods per plant was the yield component most affected by the irrigation regimes. Under rainfed , 'Negro Argel' presented lower reductions in stem biomass at the end of gr owth cycle, in leaf area duration, and in grain yield, demonstrating a high er drought tolerance, whereas Carioca was the cultivar most sensitive to wa ter stress.