FABA BEAN PRODUCTIVITY AND OPTIMUM CANOPY DEVELOPMENT UNDER A MEDITERRANEAN CLIMATE

Faba beans (Vicia faba L.) cultivated in southern Spain have an indeterminate growth habit. High levels of available water in the soil have been shown to produce excessive vegetative growth in these plants. This paper shows that potential grain yield is ca. 6000 kg ha-1 and can be achieved when leaf area duration (LAD) values are greater than 300 (LAI.days). Higher levels of LAD do not produce any increase in grain production under our Mediterranean conditions although total biomass increases until values of 600 are attained. Stabilisation of grain yield is due to a drop in the harvest index observed for LAD values over 300. Under rainfed conditions, maximum LAD values attained were always lower than 400. These results indicate that there is not an excessive leaf area and that the indeterminate growth type of faba bean may be suitable for the dryland agriculture of the area.