Abstract
An experiment was carried out to investigate the advantages of growing on the same land a mixture of cultivars, as is frequently done by farmers, instead of one cultivar. Five cultivars and 14 of their mixtures were grown in 11 environments. All mixtures, except one, yielded less, though not significantly, than their better or best component indicating that there was no yield advantage in growing a mixture of cultivars instead of the best cultivar. The yields of mixtures were in general higher than the means of their components and were more stable over different environments than those of individual cultivars. It is concluded that farmers grow mixtures for this reason and not for yield increase per se.