Effect of coating chickpea seeds with fungicides and Rhizobium isolates grown in soil infected with Fusarium oxysporum f. sp. ciceris in some parameters of seedling growth and reducing disease severity

Abstract

A study was conducted in the pesticides laboratory at the Faculty of Agricultural engineering - Plant Protection Department in Damascus for the year 2022-2023. The effect of isolates of Rhizobial of Mesorhizobium ciceri (DR - GB, 11, DR - GB, 15, and DR - GB, 20) isolated from chickpea plants for  tolerance to fungicides (Anadoul, Spiro, and VitaFlo) was evaluated according to its concentration and its ability to improve plant growth of Chickpea plants (Gab4 cultivar) and reducing the rate of infection with the fungus that causes vascular wilt (Fusarium oxysporum f. sp. ciceris) in pots under artificial infection conditions in the laboratory. The obtained results showed  that the tested isolates have the potential to form root nodules on chickpea roots, improve plant growth, and reduce the severity of fungal infection without significant differences between the isolates, as the number of nodules in healthy plants not treated with pesticides or infected with the fungus was 12.11, 11.33, and 13.25 nodules/plant for Isolates DR -GB,11, DR -GB,15, and DR -GB,20, respectively. Also, the effect of mixture fungicides with the tested Rhizobium isolates gave a difference in the effect on their ability to form root nodules according to the chemical composition of the fungicide. Anadoul and VitaFlo gave a reduction in the number of root nodules, while the fungicide Spiro had no effect on nodule formation. On the

other hand, the mixtures increased the germination rates of chickpea seeds infected with the fungus compared to the infectious control and increased plant growth indicators. It also reduced the incidence and severity of wilt disease compared to treatments treated with inoculation with isolates or pesticides alone. VitaFlo pesticide mixtures with the isolates reduced the severity of infection with significant differences with the rest of the treatments. The percentage reduction in infection severity reached 90.32, 90.32, and 93.54% for each of the isolates DR-GB.11, DR-GB.15, and DR-GB.20, respectively. the few negative interactions between seed-applied fungicides and rhizobium inoculants suggest that use of inoculant combined with seed applied fungicides, where they are likely to reduce Fusarium vascular wilt diseases, may be useful for field chickpea production.