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

Sixteen common bean (Phaseolus vulgaris L.) cultivars with different l ife cycles and growth habits were intercropped with four maize cultiva rs, to evaluate the competitive ability of each yield component, follo wing a methodology similar to that used for diallel crosses. The exper iments were done in 1991 at two sites in Brazil. The intercropping com binations were evaluated using an 8 x 8 quadratic lattice design with three replications. Two other experiments were done on monocultures, u sing a randomized complete block design with three replications. The v ariable 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 combinati ons can be explained by 'general complementing ability' (gca) of each cultivar, since there was no significant effect of 'specific complemen ting ability' (sca). The best maize cultivars to be intercropped with common bean (indicated by high gca values) were BR-201 and C-525, whic h produced high grain yields when intercropped without detrimental eff ects on legume yields. FT-84-292, Carioca 300V and ESAL506 were the co mmon bean cultivars with the highest yields when intercropped, which w as also reflected in their good performance in monoculture. Significan t cultivar x location interactions occurred only in monocultures, supp orting the belief that intercropping is a more stable cropping system.