effect of irrigation intervals on some morphophysiological traits of basil (ocimum basilicum l.) ecotypes

in order to determine the effect of different irrigation intervals on some morphophysiological traits of basil (ocimum basilicum l.), an experiment was conducted as factorial based on randomized complete block design with three replications under greenhouse conditions during 2010. treatments included five irrigation intervals with 4, 8, 12, 16 and 20 days intervals and two ecotypes of basil (green and purple). the results showed that by increasing irrigation interval plant height, spike number, spike weight and shoot dry weight between irrigation intervals decreased. purple basil was more tolerant than basil green ecotype to drought stress. interaction between irrigation intervals and ecotypes showed that the best treatment related to four days irrigation interval and purple basil ecotype. the effect of irrigation intervals on root area, root diameter mean, total length, root volume and dry weight of root was significant. in all irrigation intervals, purple basil had better performance compared to green ecotype. the results showed that by increasing in irrigation interval decreased root surface area, but increased total root length. it was concluded that increasing irrigation interval up to 12 days decreased shoot and root surface areas. increasing irrigation interval decreased chlorophyll- a, b and increased prolin amino acid content of basil leaf.