Screening of agricultural field bacteria and highlighting of their antagonistic effects on post-harvest disease fungi

In this study, the isolation of ۳۷۴ antagonist bacterial strains was carried out on two agricultural biotopes in which ۲۴۵ strains were isolated from the soil, ۶۹ from the leaves and finally ۶۰ from the roots of both plants. The screening of the antagonism of these ۳۷۴ isolates was performed against three phytopathogenic fungi, Fusarium oxysporum, Botrytis cinerea and Alternaria alternata, finding that ۲۴ isolates had antagonistic activity with a mycelial growth inhibition rate equal or higher than ۳۷%. These ۲۴ bacterial isolates were identified on the basis of morphological, physiological and biochemical characters. The comparison with the dual culture technique allowed ۶ bacterial isolates (Fr۴۳, F۳۱, Fr۵۲, F۱۰۱, B۶ and B۲۹) to be retained with areas of significant inhibition against F. oxysporum, B. cinerea and reached a value between ۲۷ and ۵۲ mm. However, these isolates showed significant inhibitory activity against mycelial growth (varies between ۲۵.۸۸% and ۶۷.۰۵%) and sporulation (varies between ۶۸.۷۴ and ۱۰۰%) of B. cinerea and F. oxysporum by their supernatant. Concerning the growth promotion, the Fr۴۳ strain was the most active with a GPE % between ۲۵.۳۱ and ۶۰, ۷۱% according to the part of the plant. This isolate was also shown to significantly reduction of the incidence disease to ۱۵.۳%, which corresponds to a significant efficacy of biological control that can reach ۷۹.۹۲% against F. oxysporum. On the contrary, the isolate F۱۰۱ exhibited the lowest value of the effectiveness of biological control versus control which can reach only ۳۷.۴۶%.

کلیدواژه ها:

Antagonistic ، Phytopathogenic fungi ، biological control ، Potato