Water deficit affects growth and grain yield of rice in various ways depending on degree, duration and timing (O’Toole and Moya. 1981)
Drought stress may occur any times during growth of the vegetative and the time of flowering. (Barnabas et al., 2008).
It is less damaging during the vegetative than the reproductive stage. As young plants are able to recover when stress is relieved. (Cruz and O'Toole. 1984)