Effect of Plant Growth Promoting Rhizobacteria (PGPRs) on yield and yield components of Black cumin under drought stress conditions in Shahr-e-Rey region

In order to study the effect of Plant Growth Promoting Rhizobacteria (PGPR) on yield and yield components of Black cumin (Nigella sativa L.) under drought stress conditions in Shahr-e-Rey region, an experiment was done as split plot based on completely randomized block design with three replications in research farm of Islamic Azad University Yadegare-Imam Khomeini (RAH) Shahre-rey Branch during 2015. In this experiment, irrigation as a major factor in three levels (55, 95, 135 mm evaporation from class A evaporation pan ) and methods of PGPRs application as a sub in four levels (seed inoculation, using in irrigation water, seed inoculation + using in irrigation water) were considered. The results showed that drought stress had significant effect on all traits at %1 level of probability, so that the highest plant height (99/18 cm), number of branches per plant (4.5), capsules number per plant (6), number of seeds per capsule (2.19), 1000 grain weight (18.2 g), grain yield (234.79 kg/ha), biological yield (626.58 kg/ha), harvest index (%42.37) were conducted in irrigation at 55 mm evaporation from class A evaporation pan. The use of PGPRs on plant height, number of branches per plant, number of capsules per plant, grain yield, biological yield and harvest index were significant at 1% level of probability. The highest amounts of traits were observed in seed inoculation + using in irrigation water. So it can be stated that the PGPRs application can reduce destructive effects of drought in black cumin. The seed inoculation + using in irrigation water were the best recommended treatment in water deficit stress conditions.