Zinc, nitrogen and salinity interaction on agronomic traits and some qualitative characteristic of canola

A 2-year greenhouse experiment was carried out at the East Azerbaijan Agronomy and Natural Resources Research Center, Tabriz, Iran, during the two seasons of 2009 to 2010 and 2010 to 2011. The experimental design aimed to study the response of canola to different nitrogen and zinc fertilizer levels under two doses of salinity stress. The experimental design was randomized complete block design (RCBD) with three replications. The obtained results from two years showed that nitrogen increased seed yield, but there was no significant differences between two nitrogen levels. Zinc application had no significant effect on seed yield. Conversely, salinity decreased seed yield and yield components dramatically. Moreover, plant height increased due to nitrogen and zinc application. Nitrogen fertilizer application improved seed number per silique and 1000-seed weight over two years. Among yield components, only number of seed per silique was affected by zinc and increased in the first year. Oil percentage decreased due to nitrogen, zinc and salinity in the first year but zinc had no significant effect on oil in the second year. Salinity stress increased glucosinolate and protein content. Other treatments, however, had no significant effect on these traits. Salt stress induction decreased N, P, K, Ca and Mg content, but increased Na, Cl and Na/K ratio.