حمیدرضا نوریزدان

Salinity stress is the main factor in reducing crop yield. One of the biological means to reduce the negative effects of salinity is using plant growth-promoting bacteria. In order to carry out this study, 30 strains of fluorescent Pseudomonads, isolated from wheat rhizosphere, were assessed for plant growth-promoting traits including production of hydrogen cyanide, siderophore and growth hormone (IAA), the ability to solubilize inorganic phosphate and salt tolerance. Four strains which were superior to others based on growth-promoting properties and salt tolerance were selected for further study. To investigate the effect of fluorescent pseudomonads on yield and yield components of wheat under different salinity levels, an experiment was carried out under twice split-split plot design in three repetitions during 1394-95 in the research greenhouse at the Faculty of agriculture and natural resources, Persian Gulf University, Bushehr. Salinity stress was considered as a major factor in four levels (0, 50, 100 and 150 mm NaCl), wheat cultivars (Kuhdasht, dehdasht, Karim and Bam) as a first sub-plots and four strains of fluorescens pseudomonads (WKZ1-93، 2-79، WB1-7 و WBO-3) along with a control treatment (no bacteria) were considered as the second subplots. At planting time, seeds were inoculated with suspension of selected Pseudomonas strains (108 CFU/ml). Saline treatments were applied gradually after four-leaf plant stage. The results of analysis of variance showed that the main effect of salinity, cultivar and bacteria was significant on all measured traits except for the number of spikes and Spike weight, for which only the main effects of variety and bacteria was significant. Interaction of salinity×variety and salinity×bacteria was significant for all traits except for the peduncle length. Interaction between varietiy×bacteria as well as salinity×variety×bacteria were significant on all traits. Results of correlation coefficient showed the highest correlation be