Evalution of Nitrogen Tolerance Indicates in Barley

This split plots experiment was conducted in research farm of Isfahan University of Technology based on randomized complete block design in triplicates to determine the genotypes with high yield and tolerance to nitrogen stress and find the best nitrogen stress indices of different barley lines. Main plot consisted of non stress (using 50 kg/ha N fertilizer before the beginning of vegetative growth, and 100 Kg/ha N fertilizer at primary stage of vegetative growth, stem enlargement and grain filling) and nitrogen stress (using 50 kg/ha N fertilizer before the beginning of vegetative growth) conditions. Sub plots were 51 barley lines. Results showed that nitrogen stress caused a significant reduction in days to heading, plant height, number of spike/m2, biological yield, grain yield and harvest index. Barley lines significantly varied in Tolerance index (Tol), mean productivity (MP), stresssusceptibility index (SSI), geometric mean productivity (GMP) and stress tolerance index(STI). Grain yield had significant positive correlation with Tol, MP, GMP and STI. Among the studied stress tolerance indices, STI and GMP were the better indices to distinguish the mosttolerant lines to nitrogen stress. Based on the result, the 40 and 15 lines were the most tolerant lines to N stress.