Changes in Yield and Yield Components of Four Cultivars of Barley Under Different Nitrogen Levels in Isfahan Region

: In order to study the effect of different nitrogen levels on yield components and seed yield of three barley cultivars, an experiment was conducted in 2011-2012 in a research farm of farming building of Islamic Azad University Khorasgan (Isfahan) Branch located in Khatunabad village (latitude 32o /40' N and Longitude 51o /48' E). A split plot layout within randomized complete block design with 3 replications was used. Main plot were different level ofnitrogen fertilizer (0, 75and 150 kg ha-1) from urea source, and sub plot were different cultivars (Reyhan03Nosrat, Valfajr and Yousef). Condition represented the effect of nitrogen was significant on number of spikes m-2, seed yield, biological yield and harvest index.50 kg N ha-1fertilizer treatment, resulted the maximum of all mentioned factors except biological yield. Effect of cultivar was significant on number of spikes m-2 and biological yield. The maximum of all mentioned factors related to Valfajr cultivar.Interaction of nitrogen and cultivar was significant on number of spikes m-2, seed yield andharvest index. On the basis of the results obtained, the fertilizer treatment 50 kg N ha-1 and Valfajr cultivar might be suitable for barley productive under the condition similar to the present study