EFFECT OF PLANT DENSITY ON YIELD AND COMPONENTS OF YIELD OF FABA BEAN

Abstract

Field experiments using two Vicia faba L. cultivars, Outlook faba bean and Chinese broad bean, were grown at six densities (13, 25, 38, 50, 63 and 75 plants m−2) at two locations in Saskatchewan for 2 yr. A diminishing yield response to density was observed over this range of densities, with optimal economic seeding densities attained at 38 plants m−2. For the larger-seeded Chinese broad bean, simulations indicated that a lower density of 25 plants m−2 was adequate if the seed cost approached twice that of the product price. Density effects were highly significant (P < 0.01) for all yield components except seed weight in Chinese broad bean and seeds per pod in both cultivars. Of the primary yield components, pods per plant exhibited the greatest sensitivity to changes in plant density, with Outlook faba bean being affected to a much greater extent. The number of pods per pod-bearing node was the major determinant of yield and yield stability in the highly indeterminate Outlook faba bean. The importance of pods per pod-bearing node was reduced in the more determinate Chinese broad bean, where podded nodes per plant showed greater sensitivity to plant density changes. It is suggested that efforts to produce a more determinate cultivar by reducing the number of podded nodes per plant may result in a concomitant stabilization of pods per pod-bearing node.Key words: Vicia faba, yield components, plant density, faba bean, seeding rate