COMPETITIVE ABILITY OF MAIZE AND COMMON BEAN (PHASEOLUS-VULGARIS) CULTIVARS INTERCROPPED IN DIFFERENT ENVIRONMENTS

Sixteen common bean (Phaseolus vulgaris L.) cultivars with different life cycles and growth habits were intercropped with four maize cultivars, to evaluate the competitive ability of each yield component, following a methodology similar to that used for diallel crosses. The experiments were done in 1991 at two sites in Brazil. The intercropping combinations were evaluated using an 8 x 8 quadratic lattice design with three replications. Two other experiments were done on monocultures, using a randomized complete block design with three replications. The variable considered was 'maize equivalent yield', obtained by adjusting for the price difference between the species. The method used showed that the differences in performance of the many intercropped combinations can be explained by 'general complementing ability' (gca) of each cultivar, since there was no significant effect of 'specific complementing ability' (sca). The best maize cultivars to be intercropped with common bean (indicated by high gca values) were BR-201 and C-525, which produced high grain yields when intercropped without detrimental effects on legume yields. FT-84-292, Carioca 300V and ESAL506 were the common bean cultivars with the highest yields when intercropped, which was also reflected in their good performance in monoculture. Significant cultivar x location interactions occurred only in monocultures, supporting the belief that intercropping is a more stable cropping system.