Abstract Plant growth regulators have plentiful applications in agriculture such as delaying or accelerating maturity, stimulation, flowering, abscission, controlling weeds and so on. Gibberellins induce flowering in long-day plants which require chilling. Heading was delayed by addition of gibberellic acid (GA3) to the root zone. Water shortage and the increasing competition for water resources between agriculture and other sectors compel the adoption of irrigation strategies in semi-arid Mediterranean regions, which may allow saving irrigation water and still maintain satisfactory levels of production. The field experiment was conducted in Zahak located at the sistan and balouchestan provinces of Iran. Treatments included water stress are control (a1), 10 days once (a2), 20 days once (a3) and gibberellic acid including 0 ppm (b1), 50 ppm (b2), 100ppm (b3) and 150ppm (b4). Analysis of variance showed that the effect of water stress and gibberellin on biological and grain yield was significant.