Virulence and vegetative compatibility of Algerian isolates of Fusarium oxysporum f. sp. lentis

Thirty-two isolates of Fusarium oxysporum f. sp. lentis (Fol) were obtained from wilted lentil plants collected from different lentil growing areas in north-western Algeria. Pathogenicity tests were performed on all isolates. The isolates were also assessed for vegetative compatibility using nitrate non-utilising mutants (nit). Isolates that formed mutual heterokaryons were placed in the same vegetative compatibility group (VCG). The Fol isolates represented a single race but differed in their aggressiveness on susceptible lines. In the vegetative compatibility test, three types of nit were obtained (nit-1, nit-3 and Nit-M) on the basis of the phenotype. Nit-1 mutants were the most frequent (63%), followed by Nit-M (31%) and nit-3 (6%). On the basis of their ability to form heterokaryons, all the lentil pathogenic isolates were grouped into a single VCG 0471. This is an indication of the homogeneity of the Algerian Fol population

Biocontrol of Chickpea Fusarium Wilt by Bacillus Spp. Rhizobacteria

Among 131 rhizobacteria isolates, 29 potentially antagonistic strains were screened in in vitro assays. The five antagonistic Bacillus spp. Rb29, Rb6, Rb12, Rb4, and Rb15 showed the most inhibitory effect against FOC1 (from 25.63 to 71.11%), mycelial growth, and FOC2 (from 28.43 to 60.65%) in vitro. Results also revealed that production of volatile metabolite, components and inhibition of the test pathogen by volatile metabolites varied among different antagonistic rhizobacteria. Isolates Rb29, Rb6, Rb12, Rb4, and Rb15 produced more volatile metabolites which inhibited mycelial FOC growth by 40%. Chickpea Fusarium wilt severity caused by FOC1 was reduced from 60 to 99% in the susceptible cultivar ILC 482 treated with antagonistic Bacillus spp. (Rb29, Rb6, Rb12, Rb4, and Rb15) in pot assays and by 98, 81, 68, 64, 57.20%, respectively, in the field trials. As for their beneficial effects on disease control, the results revealed that Bacillus spp. may improve plant growth and disease control