Previous experiments using grafted plants of five genotypes of common bean (Phaseolus vulgaris L.) grown under water deficits indicated that differences in yield were determined in the root system. There was no effect of shoot genotype. To determine whether this result holds for a wider range of genotypes, genetic variation among shoots was examined by evaluating yields of 15 shoot genotypes on a rootstock of a single genotype in trials at two locations with contrasting soil types. Differences among yields of shoot genotypes were detected in three of the four screening trials. The two highest‐yielding shoot genotypes from these trials (H6 Mulatinbo and BAT 1297) were evaluated in final set of trials with two genotypes of contrasting adaptation to drought, using all possible combinations of root and shoot genotypes. Only a root genotype effect (P < 0.01) was found for yield. Shoot dry weight at maturity also showed a strong root effect. Harvest index varied with root genotype at both sites, but also varied with shoot genotype at one site. Genetic variation in shoot characteristics was also shown by a highly significant effect (P < 0.01) of shoot genotype on days maturity. Although the survey of a range of genotypes detected variation in shoot genotype, the effect of shoot genotype on growth and yield under water deficits was small compared with that of root genotype.