Investigation of the Effect of Plant Growth Promoting Rhizobacteria on Some Growth Indices and Yield Parameters of Safflower Under Different Soil Salinity Levels

In order to evaluate the effect of plant growth-promoting rhizobacteria) PGPR( on salt tolerance in vegetative and reproductive growth stages of safflower (Carthamus tinctorius), a randomized complete block design with a factorial combination of bacterial inoculation and salinity, each in three levels, and four replications was conducted in experimental glasshouse of Vali-e-Asr University of Rafsanjan. Bacterial inoculation treatment included control (non inoculation), inoculation with Pseudomonas fluorescens strains 12 and 52 and salinity stress treatment included (electrical conductivity of 1 (control), 6 and 12 dS.m-1 in soil). Results showed that leaf area decreased with increase in salinity, but Pseudomonas fluorescens strain 12 significantly increased leaf area. Both strains significantly increased leaf chlorophyll index at mid grain filling stage comared to to uninoculated control. Finally, grain number per capitol, grain yield per plant, mean grain weight, oil yield, and biological yield decreased with increasing in salinity level, but capitol number per plant and harvest index remained unchanged. Two bacteria strains applied in this study increased only oil concentration in control level of salinity and were uneffective on other yield components. It seems that bacterial inoculation may improve some vegetative indices of safflower but its impact on yield needs to be further studied