effects of water stress on growth indices, yield, and water use efficiency of pepper plant in greenhouse condition

the present research was conducted to study the effect of irrigation treatments on growth indices, yield, and water use efficiency of long green pepper (capsicum annuum l.) at the research greenhouse of shahrekord university. this experiment was done in a clay-loam soil using randomized design with four treatments i.e. 40%, 60%, 80%, and 100 percent of water requirement and three replications, in 12 pots, during 2012. the obtained results from statistical analysis indicated that the effect of irrigation water on growth indices, yield, and water use efficiency (wue) was significant at 5% level. maximum yield and maximum water use efficiency were achieved in treatment of 100 percent water requirement i.e. full irrigation. furthermore, it was observed that water use reduction by 20%, 40% and 60 percent led to reduction in yield by 26.98%, 50.92% and 69.49 percent, respectively. moreover, it was observed that water use reduction by 20%, 40% and 60 percent led to reduction in water use efficiency by 10.56%, 22.24% and 29.35% percent, respectively. since there was no significant difference in yield between 100% and 80 percent treatments, it is recommended that under water shortage conditions, the maximum reduction in water application be limited to 20 percent of water requirement.