effects of seed nourished by different levels of nitrogen, biofertilizers and drought stress on germination indices and seedling growth of wheat (tritium aestivum) cv. sayonz

in order to study the effects of different levels of drought stress and plant growth promoting rhizobacteria on the germination indices of seeds harvested from wheat (tritium aestivum l.) cv. sayonz in the field treated with different levels of nitrogen, in controlled conditions, a factorial layout based on completely randomized design with three replications, was conducted. treatments included the seeds that collected from field that received amount of 0, 120, 240 and 360 kg.ha-1 nitrogen fertilizer, types of biofertilizer (nitragin, biophosphouros and control) and different levels of drought stress (0, -4, -8 and -12 bar). the results showed that simple effects of levels of biofertilizers and levels of drought stress were significant on the all germination characteristics of wheat, except for mean germination time, radicle length to plumule ratio and dry weights of radicle to plumule ratio, while levels of nitrogen fertilizer only was significant on germination, germination rate and germination index. the interaction effects had showed that the seeds harvested from nitrogen fertilizer at 240 kg/ha and drought stress 0 and -4 bar had the highest germination. nitragin bifertilizer increased drought stress resistance compared with control, so that the stress level -4 bar reducing germination for seeds treated with biosphouros and non-inoculated, than plants treated with nitragin, were 40 and 79%, respectively. effects of three nitrogen fertilizer, biofertilizer and levels of drought stress were not significant on the characteristics measured.