Effect of foliar application of zinc sulphate on grain yield, oil and protein content in four rapeseed (Brassica napus L.) cultivars

To evaluate the effect of foliar application of zinc sulphate on plant characteristics of rapeseed cultivars a field experiment was carried out during 2008-2009 growing season in Shirvan-Chardavol Field Station of Ilam، Iran. The experiment was performed using factorial arrangement in randomized complete blocks design with three replications. The experimental factors included zinc sulphate foliar application (control، foliar application at stem elongation، and flowering stages) and four rapeseed cultivars (Hyola401، Hyola308، Zarfam and Sarigol). Results showed that foliar application significantly affected grain yield، silique. plant-1، grain. silique-1، 1000 grain weight، oil and protein content. Foliar application of zinc sulphate at stem elongation and flowering stages increased grain yield (by 11% and 17%، respectively). Also، oil and protein contents were increased by application of zinc sulphate. The highest oil (35. 1%) and protein (27. 3%) contents obtained from application of zinc sulphate at flowering stage when compared to control treatment. Cultivars were significantlydifferent for grain yield، yield components، silique length، oil content، protein content and plant height. The highest 4201 kg. ha-1) and lowest (2981 kg. ha-1) grain yield obtained from Zarfam and Sarigol cultivars، respectively. Oil and protein contents were also significantly different in rapeseed cultivars. Zarfam had the highest oil content (34. 9%) in comparison to the other cultivars. It is concluded that that zinc sulphate foliar application on Zarfam cultivar at flowering stage resulted in higher seed yield under the climatic conditions of the experimental site.