Responses of cultivars of canola to sulfur fertilizer and plant densities under climatic condition of Gorgan region, Iran

Abstract

In many regions in the world sulfur deficiency has been recognized as a limiting factor for canola seed production. To investigate the effect of sulfur fertilizer and plant density of new cultivars of canola under climatic condition of Gorgan region and its suburb, an experiment was conducted in 2004-2005 in form of split split plot design with in randomized complete block design with three replications was used. The main plots consist of level of sulfur fertilizer (0, 125 and 150 kg/ha). Subplots were composed of three plant densities (60, 80 and 100 plants/m 2 ), and sub subplots were three cultivars of canola (RGS003, Hyola401 and Hyola420). Sulfur fertilizer had significant effect on the distance of first branch from earth, the number of pods in plant, oil percentage, biological yield and harvest index. Cultivar had significant effect on all characteristics, except of stem diameter and the number of seeds per plant. The interaction between sulfur fertilizer and cultivar had no significant influence on traits. Also, oil percentage was affected by plant density and cultivar interaction. There were positive and significant correlations between seed yield and length of pod in main stem (r = 0.436 ** ), and seed yield and length of pod in secondary branch (r = 0.488 ** ). Hyola401 also had the highest seed yield, the number of seeds per plant, a thousand seed weight, oil yield, biological yield and harvest index, which had a significant difference with other cultivars. The correlation between oil yield and seed yield was significant and positive (r = 0.790 ** ), it seems that seed yield had capacity and capability to influence oil yield. So under similar condition with this study, application of 250 kg S/ha besides using Hyola401 and the plant density of 60 plants per m 2 seems appropriate.