Genetic variation for improving water-stress tolerance has been lost during selection and modern breeding in wheat. Thus, finding genetic sources for drought tolerance is more likely in landraces and wild species than in modern varieties. The objectives of this study were to determine variations for water-stress-induced apical sterility and some related characters among Iranian landraces and wild species, and to analyse the contribution of apical sterility and related characters to grain production of the genotypes. The results showed considerable variation among wheat genotypes for water-stress-induced apical sterility and its related characters. Variations were also observed between ploidy levels for some of these characters. However, the amount of variation observed among the genotypes was not the same for all characters and in all treatments. Considerable significant pair-wise differences were also observed between genotypes for apical sterility under water-stressed conditions. In addition, regression analysis revealed that grain yield per plant is mainly dependent on ovary weight under well-watered conditions and on anther weight under water-stressed conditions.