A set of experimental hybrids obtained following the "Nested" mating design (Hallower and Miranda, 1981) was used to analyze genetic variability, in the source population, for drouglrt resistance, calculated as the relative yield reduction underdrought with respect to the irrigated control and drought susccptibility index "S" (Fisher and MAurer, 1978). The results indicatc that the major part of genetic variability for this character was accounted for by the additive variance with a high heritability expressed in narrow sense. Of great interest is the inbred line HAS whose two hybrids (7 and 8) have reduced their yield under drought by only 14 and 9% in relation to the âverage field red uct ion of 42%. The escape effect of this result is insignificant and for this reason physiological studies are planned to detect the responsible resistance mechanisms. Selection for high seed yield and drought resistance seems to be possible for the environment of Central Italy because the correlation between yield potential and the "S" index is non-significant, but in very arid areas this possibility might not be valid.