Water scarcity and soil salinity are two important limitations for agricultural production in arid regions, and Yazd province, with regard to its desert condition, encounters this problem seriously. Since large portions of renewable water resources are used for agriculture in Iran , and irrigation efficiency is also low, selection and application of any strategy for optimization of water application is important. In recent years, one of the strategies for crop production with maximum income under water scarcity conditions is deficit irrigation. One method of deficit irrigation, called Partial Rootzone Drying (PRD), is a new irrigation technique that improves water use efficiency, while minimizing adverse effects on yield. Canola crop, with high oil content in its seeds (40-45 precent pure oil) and resistance to soil salinity and different climatic conditions of Iran , has great ability for satisfying the main part of country , s requirements for edible oil. This research was carried out on winter canola ( Brassica napus L., cv. Zarfam) under greenhouse at Agriculture and Natural Resources Research Center of Yazd in 2006. The experiment was performed as a complete randomized block design with three replications that contained salinity and irrigation water factors. Salinity factor had four levels of S 1 =3-4, S 2 =6-7, S 3 =9-10 and S 4 =12-13 dS/m and irrigation water factor had three levels of W 1 =30, W 2 =50 and W 3 =80 percent of management allowed depletion. Soil texture was loamy sand. PRD experiment was performed in five treatments (T 1 , irrigation at right and left sides of pots; T 2 , alternating irrigation; T 3 , irrigation only at right side; T 4 , irrigation only at right side without central plate and T 5 , alternating irrigation without central plate) with irrigation water salinity of 6.56 dS/m and irrigation rate of 50% MAD with three replications and in box containers which had a very thin plate in their center. The results showed that under simultaneous salinity and defficit irrigation, increasing salinity to S 3 level increased significantly the canola dry matter by 14.64% and increasing salinity to S 4 level decreased the plant dry matter production by 10.95%. The results of PRD treatments showed that grain yield decreased from 18.11 g/plant in control to 16.38 g/plant in T 2 treatment but this reduction was not statistically significant. Water use efficiency of control was 0.376 and that of T 2 treatment was 0.673 kg/m
