Interaction effect of zeolite and salt stress in reproductive stage of four canola varieties

Introduction Canola (Brassica napus L.) is one of the most important plants to produce edible oil in Iran and in the world and also one of the negative factors for crop plants is the relative salinity of irrigation water in some areas of Iran. According to the researchers, salinity incorporates high concentration of minerals that prevents plant growth. Effects of Salinity significantly in arid and semi-arid areas, areas with limited rainfall, high temperatures combined with high evaporation with high chemical fertilizers, and poor water and soil management, is observed and is an important crop production problem in these areas. Zeolites are a group of natural porous minerals that acts as a molecular sieve with its crystal structure practices and allow some passage of some ions and block the passage of some others, due to open channels in their ionic lattice. Due to zeolites high porosity and stems from its crystal structure, they can absorb up to 70% of bulk with water. Recent research on various applications of zeolites in crop plants as well as its effect on the process of how to prevent the entry of toxic ions such as sodium and absorption of essential nutrients has been concentrated crop and the interaction effect of the two substances necessary to appear on canola This experiment intends to determine the ways of control damage caused by 5 and 10 10 ds m-1 salinity on yield and yield components on four canola cultivars with application of 8 ton hec-1 zeolite. Materials and methods The experiment was conducted as split plot factorial in randomized complete block design with three replication at the greenhouse research station of Agricultural Faculty of Tarbiat Modares University started in autumn 2013 and at the end of spring 2014 greenhouse operation was ended. Treatments were salt stress from beginning of flowering at three levels included control, 5 and 10 ds m-1, zeolite application with two levels included control and 8 ton hec-1 and varieties with foul levels Zarfam, Sarigol, Hayola and RGS. From 29 October 2013 (sowing) to 20 May 2014 (harvesting), Greenhouse environment was with normal light and temperature conditions. The soil of pots was sand mixed with field soil in ratio of 1:1. Applied zeolite was clinoptilolite. To creation of appropriate drainage and prevent the accumulation of salt, three holes with one centimeter diameter was generated at the bottom of each pot. Salinity was started by adding salt mixture to irrigation water, before flowering. The final salt was mixed with salt water of Tehran, Gom and Kashan wells with ration of 2:2:4:3:4 and after standardization calculated with electrical conductivity meter and finally the salt water was transferred to each pot with graduated containers. On this experiment grain yield, yield components, yield and oil percentage and SPAD were measured. Mean comparisons were performed by LSD test using in SAS 9.2. Results and discussion The results showed that the effect on all traits except harvest index was significant, and none of the treatments had no significant effect on oil percent Number of grain per pod, and salt stress did not affect harvest index and zeolite on grain yield, number of pods, number of grain per pod, harvest index and greenness significant effect. Results showed that application of zeolite increases grain yield 9 and 26 percentage in control and average stress levels of RGS. But in severe stress condition because of severe prevent water absorption by increasing the osmotic potential into the roots environment, had not significant effect on experimental varieties. Application of zeolite in control condition and non-application of zeolite in severe stress on Zarfam number of pod were the highest and lowest with the difference of 36 %, respectively. Sarigol in control condition and Zarfam in severe showed the highest and lowest of 1000 grain yield with the difference of 22 %, respectively and RGS in control condition and Hayola in severe showed the highest and lowest of number of grain in pod with the difference of 54 %, respectively. It was also observed that application of zeolite in control stress condition on RGS and non-application of zeolite on Hayola in severe stress condition showed the highest and lowest of dry weight with the difference of 50 %, respectively. Results showed that, Sarigol in control condition of salt stress and zeolite was the highest of oil yield compared to Zarfam in condition of severe stress and non-application of zeolite with 66 percentage. Results of the experiment was shown, Zarfam in average stress and non-application of zeolite showed the highest amount of SPAD compaire to the same variety in severe stress and non-application of zeolite with more than double. Conclusions Application of Zeolite increases grain yield of Zarfam and all three levels of salinity reduces this trait in canola varieties, significantly. Due to the low price (500 rials per kg) of zeolite and abundance of this mineral in our country, it can be used to prevent performance degradation of the material used in high salinity lands. Sarigol showed higher values of SPAD index than other cultivars, in terms of salinity and application of zeolite prevent the reduction of SPAD index values in terms of stress.