effect of irrigation intervals on some morphophysiological traits of sesame (sesamum indicum l.) ecotypes

in order to evaluate the effect of different irrigation intervals on some morphophysiological traits of sesame (sesamum indicum l.), an experiment was conducted under greenhouse conditions during 2009. the experiment was based on a randomized completely design with three replications. treatments included four irrigation intervals with 4, 8, 12 and16 days intervals and two ecotypes of sesame (kalat and se-ghaleh). the results showed that there were significant differences in plant height, node number, internodes length, capsule number, capsule weight and shoot dry weight between irrigation intervals. with increasing irrigation intervals, the mentioned traits decreased. se-ghaleh was more drought tolerant than kalate ecotype. interaction between irrigation intervals and ecotypes showed that, the best treatment related to four days irrigation interval and se- ghaleh ecotype. the effect of irrigation intervals on surface area, diameter, total length, volume and dry weight of root was significant. in all irrigation intervals, se-ghaleh showed better performance. the results showed that increased irrigation interval caused a decreasing in root surface area, but increasing in total root length. with increasing irrigation interval, transpiration and photosynthesis rates significantly decreased. it was concluded that increasing irrigation interval up to 12 days decreased shoot and root surface areas. the se-ghaleh ecotype was more drought tolerance than kalat.