Effect of carboxin-thiram fungicide on viability and effectiveness of some selected plant growth promoting Pseudomonas strains in wheat seed.

In addition to that biofertilizers have positive effects on soil stable fertility; they also have some other beneficial attributes such as economical and environmental. Therefore they can be used as a suitable substitute to replace all or at least some of chemical fertilizers. Biofertilizers include Plant Growth Promoting Rhizobacteria (PGPR). One of the most important components of PGPR group is Pseudomonas. These bacteria can increase plant growth through direct and indirect mechanisms. Considering wide use of Carboxin thiram to control fungal pathogens in wheat cultivation in Iran, this project was designed and performed to define the effects of this fungicide on the establishing association relation with species of Pseudomonas. Performing green house test, use and non-use Carboxin thiram effects on growth indexes of wheat plant (Chamran Cultivar) association conditions with 2 Pseudomonas species (P.fluorescence and P.putida) were studied. Also effect of Carboxin thiram on two Pseudomonas species inoculant formulations (powder and liquid) on wheat seeds was surveyed in in-vitro condition. Bacteria counting test results showed that highest population of bacteria were the result of using liquid formulations of two species . Powdery formulations of bacteria decreased the number of bacteria on wheat seeds . Using Carboxin thiram also decreased the number of bacteria on wheat seeds in two different species.In the worest condition, the residual population of bacteria on wheat seeds after using powdery formulation of bacteria with Carboxin thiram were more than 5 Log unite . Greenhouse results showed that bacteria formulations had meaningfull effects only in plant height(P%1) and panicle length (p%5) and Carboxin thiram also had only meaningfull effect on 1000 seed weight (P%5) and interaction of bacteria formulation in Carboxin thiram had no any statistical meaningfull effects on all studied indexes. On the basis of plant height and panicle length and bacteria counting test results using two formulations of P.fluorescense had the same results . But in the case of P.putida ,liquid formulation was more effective than powdery form on panicle length. Final results showed that with Caboxin thiram it is better to use liquid formulation of these two species of pseudomonas bacteria. Keywords: Pseudomonas, Carboxin thiram, wheat