Seed yield
The sunflower seed yield was affected by WD and H as well as the interaction of WD×H treatments (Table 4).
The water deficit reduced seed yield in sunflower plant and the less yield was obtained from I treatment (Fig 2).
The Euroflor and Allestar hybrids had highest seed yield in full and limited irrigation condition, respectively. Among the hybrids, the Karaj hybrid had less seed yield under the well-irrigated and moderate irrigation deficit. However, among the current
hybrids, the Euroflor hybrid had less seed yield under extreme irrigation deficit condition (Table 4).