As water deficiency becomes a more frequent cause of the reduction in wheat yield levels, the search for donors of drought tolerance to be bred into adapted land races becomes urgent. Drought tolerance has been evaluated by the 13C discrimination method in six land races of emmer wheat (Triticum dicoccum SCHRANK), compared with land races, obsolete cultivars and modern varieties of soft wheat (Triticum aestivum L.). The results of a two-year trial show that most of the genetic resources of emmer wheat, and intermediate land races of wheat are predisposed to drought tolerance. These varieties respond to dry conditions more sensitively, as they close their pores earlier (a lower value of the discrimination of 13C isotope). As for other land races and the top modern varieties of soft wheat, they are not thought to be predisposed to drought tolerance and their crop stands are liable to serious damage