Responses of Canola Morphological and Agronomic Characteristics to Zeolite and Zinc Fertilization under Drought Stress

Research was performed during the 2010 and 2011 growing seasons to investigate the effect of zeolite and zinc (Zn) foliar application on the qualitative characteristics and oil yield of canola cultivars at different moisture regimes. A factorial split-plot experiment was performed on the basis of the randomized complete block design with three replications in the Seed and Plant Improvement Institute, Karaj, Iran. The treatments were as follows: (1) irrigation (I), complete (I-1), and restricted (I-2) at the pod formation stage, (2) zeolite (Z), 0 (Z(1)), and 15 t ha(-1) (Z(2)), and (3) Zn, zinc sulfate concentrations of 0%, 0.1%, and 0.2 % (Zn-1, Zn-2, and Zn-3) at the pod formation stage. These treatments were applied on Licord, RGS003, and Opera cultivars. The results show that the simple effect of treatments were statistically significant for all assessed traits at P < 0; as well as the interaction effects of Z and Zn (P < 0.01) and the interaction effects of I and cultivar (P < 0.01). The greatest rates of all studied traits were obtained by applying Z(2)Zn(2) (15 ton ha(-1) zeolite and 0.1% Zn sulfate) in both irrigation regimes. The rates of grain yield, biological yield, and harvest index improved by 43.82%, 73.99%, and 30.04%, respectively, using a combined application of Z and Zn. Therefore, based on the low cost of natural Z and a low Zn intake, these treatments could be used to enhance the performance of canola, especially in regions that are exposed to water stress.