Evaluation of Yield and Growth Indices of Canola (Brassica napus L.) Cultivars in Different Nitrogen Fertililization Levels

In order to evaluation of effects of different nitrogen fertilization levels on yield and growth indices of canola (Brassica napus L.) cultivars, an split plot experiment based on randomized complete block design was conducted in Research Farm Islamic Azad University, Ardabil branch in 2007. Factors were: nitrogen fertilizer at four levels (0 as control, 50, 100 and 150 kg N/ha) in the main plots and canola cultivars at three levels (Clover, Opera  and Okape) in the sub plots. The results showed that various levels of nitrogen fertilizer affected yield and growth indices of Brassica napus. Means comparisons in compound of treatment cultivar x levels of nitrogen showed that maximum grain yield was obtained by the plots which was applied 150 kg nitrogen/ha with opera cultivar. Investigation of variances trend of total dry matter indicated that in all of treatment compounds, it increased slowly until 215 days after sowing with increasing of nitrogen fertilizer and then increased rapidly till 299 days after sowing. From 299 days after sowing till harvest time, it decreased due to increasing aging of leaves and decreasing of leaf area index. Increase in N levels also significantly increased the crop growth rate and the maximum of it was observed by the plots that received 150 kg N/ha with opera cultivar. In addition, in all of treatment compounds, CGR increased slowly until 243 days after sowing and then decreased slowly till 257 days after sowing. From 257 days after sowing till harvest time, it decreased due to increasing aging of leaves and decreasing of leaf area index. Thus, it can be suggested that in order to increasing of grain yield, total dry matter crop growth rate and the other of physiological indices should be applied opera cultivar with 150  kg N ha-1 in conditions of Ardabil Plain

Investigation of Correlation between Traits and Path Analysis of Corn (Zea mays L.) Grain Yield at the Climate of Ardabil Region (Northwest Iran)

In order to study correlation between some traits and yield components of corn and to determine the most effective factors on its yield, an experiment was conducted at the agricultural research farm of university of Mohaghegh Ardabili in 2007. The experiment was conducted as a split plot in a randomized complete block design with four replications. Main plots were allocated at three levels to different planting dates (10, 20 May and 30 June) and subplots were allocated at the different levels of nitrogen fertilizer (0, 75, 150, 225 Kg N ha-1). The utilized corn seed was SC 404 hybrid. Sequential path analysis was used for evaluation of relationships between yield and yield attributes and to eliminate less important variables by using SPSS. Results showed that kernel per ear has the most correlation (r = 0.53) with grain yield. The grain yield and kernel per ear indicated negative and significant correlation with grain thickness (r = -0.33 and r = -0.52 respectively). The correlation between grain protein and thickness was negative and significant, too (r = -0.52). Results obtained from path analysis revealed that kernel per ear has more importance for selecting corn cultivars with high yield among different traits. Kernel per row and grain length had an effect on grain yield. Thus, these two traits can be attend in breeding programs and also be effective as a potential traits in improving desired corn cultivars