Impact of arbuscular mycorrhizal fungus (<i>Rhizophagus irregularis</i>) on disease symptoms caused by the ascomycete fungus (<i>Mycosphaerella fijiensis M.</i>) in Black Sigatoka-resistant banana plantain

Abstract

Banana (Musa spp.) is grown throughout the tropical and subtropical areas. The Black Sigatoka, however, represents a major threat to world production. This study evaluates the effect of the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis MUCL 41833 on four plantain cultivars with different resistance against Mycosphaerella fijiensis. The mycorrhized banana plantlets of four cultivars were grown under greenhouse and the effect of AMF on micropropagated banana plantlets was evaluated. After 35 days, the height and the diameter of the pseudostem, then the leaf area were measured. The significant effect of the cultivar on the height of the pseudostem and the leaf area and significant effect of M. fijiensis on the diameter of the pseudostem, the height of the pseudostem and the leaf area were obtained. Plants infected with M. fijiensis show more symptoms of the disease than healthy plants. Symptoms were delayed in bananas inoculated with AMF compared to bananas not inoculated with AMF. The disease progressed more rapidly in cultivars Bâtard and C292 than in cultivars CRBP39 and F568. These results suggest that AMF may decrease symptoms of Sigatoka, at the early stage of infection with M. fijiensis. AMF may be a promising tool for the pre-adaptation of micropropagated banana plantlets.

Keywords: Plantain, Rhizophagus irregularis, arbuscular mycorrhiza fungi, Mycosphaerella fijiensis, disease control method.