The Effects of some Arbuscular Mycorrhizal Fungi on Plant Growth and Biocontrol of Ascochyta Blight in Two Chickpea Varieties

Ascochyta blight caused by the fungus Ascochyta rabiei plays an important role in reducing chickpea yield and seed quality in many parts of the world. The aim of this study was to investigate the potential of arbuscular mycorrhizal fungi (AMF) in improving plant growth parameters and the biocontrol of this pathogen on two chickpea varieties.

Five AMF species including Funneliformis mosseae, Gigaspora margarita, Glomus fasciculatum, Glomus versiform, and Rhizophagus irregularis were investigated for their potential in suppressing the Ascochyta blight on two chickpea varieties, Saral and Bivanij in comparison with chlorothalonil fungicide. Their effects were also examined on some plant growth parameters in the presence of a pathogen. This research was performed in greenhouse in a factorial experiment based on a completely randomized design including 16 treatments with six replications.

Chlorothalonil had the highest suppression against A. rabiei in both chickpea varieties. All AMF (except G. fasciculatum in variety Saral) significantly decreased the disease index compared to the infected control. The highest disease suppression by AMF was obtained by R. irregularis (46.15%) and G. versiform (42.30%) on variety Saral and by G. fasciculatum (40%) on variety Bivanij. Most of AMF enhanced chickpea growth parameters in the presence of pathogen with R. irregularis and G. fasciculatum showing the best effects on Saral and Bivanij, respectively. G. fasciculatum had the highest root colonization on both chickpea varieties.

The results of this study showed that AMF can promote plant growth parameters and attenuate the A. rabiei-induced losses in two chickpeas varieties. The rates of disease suppression and growth promotion depended on plant genotype and AMF species. No relationship was observed between the rates of root colonization by AMF and the reduction of Ascochyta blight symptoms