Screening of some isolates of rhizobium bacteria (Mesorhizonium ciceri) that are tolerant to fungicides and evaluating their effectiveness in against wilt rot fungi in the laboratory.

Abstract

The research was conducted in the laboratories of the Plant Protection Department - Faculty of Agriculture, University of Damascus, for the years 2021-2022 to obtain defined and described isolates of the rhizobium bacterium (Mesorhizonium ciceri) isolated from the roots of chickpea plants (Cicer arietinum L.) from three governorates: Damascus and Daraa and Qunaytra, for screened against fungicides used in seed treatment (Spiro, Anadol and Vitaflo). The antagonistic activity of moderately sensitive and resistant Rhizobium isolates against wilt-rot fungi: Fusarium solani, Fusarium oxysporum, and Rhizoctonia solani was evaluated in the laboratory. Sixty isolates of the bacterium Rhizobium (Mesorhizonium ciceri) were isolated from the root nodules of chickpea plants. The results showed that 23 isolates were highly sensitive to the studied fungicides, 13 and 21 isolates were moderately resistant to the studied fungicides, respectively. The moderate and resistant bacterial isolates showed different antagonism to the three fungi according to the rhizobium isolate and the different type of fungus. However, the inhibitory effect of the rhizobium isolates was highest on F. solani, followed by Rhizoctonia solani, and moderate on F. oxysporum. The bacterial isolates Rf-GB,12, DR-Lo,2, Rf-Lo,4, Q-MR,14, DR-Lo,6 and DR -GB,20 gave high antagonism towards the three fungi without significant differences between them.