Effect of different levels of plant density and nitrogen fertilizer on grain yield and its components and some quality traits in two sesame (Sesamum indicum L.) cultivars

A field experiment was conducted to evaluate the effect of different levels of plant density and nitrogen fertilizer (N) on grain yield and its components and some quality traits in two sesame (Sesamum indicum L.) cultivars-using split-split plot arrangement in randomized complete block design with three replications at Agricultural Research Station of Kushkak, College of Agriculture, Shiraz University in 2002 cropping season. The treatments included: plant density (16.6, 20.8, 33.0 and 41.6 plants m-2) assigned to main plots, nitrogen fertilizer (N) (0, 60, and 120 kg ha-1) and cultivars (CV) (Local Zarghan and Darab-14) were randomized in sub-plot and sub-sub plots, respectively. Both plant density and N fertilizer had significant effect on days to maturity, capsule number per plant, 1000-grain weight, grain yield, harvest index, oil and protein contents. Grain yield of cultivars increased with increased N rate, but CVs had different response to N levels. There was a significant interaction between N × plant densities × CV on grain yield, and the highest grain yield (2161 kg ha-1) was produced by Darab-14. in 41.6 plants m-2 and 60 kg N ha-1, which was not significantly different from local Zarghan, at this plant density. Grain yield had negative and significant correlation (r= -0.31*) with harvest index and positive correlation (r= 0.23) with 1000-grain weight and oil content. Grain oil content had negative and significant correlation (r= -0.86**) with grain protein content. In summary, two sesame cultivars had no significant yield differences, but it local Zarghan, was more responsive to N application. Of course Darab-14 is harvested later relative to local Zarghan and therefore, it is recommended early maturity local Zarghan be sown where there are early autumn rain and cold with less N fertilizer application.