A Greenhouse bioassay for the Fusarium oxysporum f. sp. cubense x Grand Naine (Musa, AAA, Cavendish subgroup) interaction

Abstract

Several disease resistance screening protocols for Fusarium wilt of banana (causal agent Fusarium oxysporum f. sp. cubense - Foc) under greenhouse conditions have been reported. Here, we report a standardised rapid and reliable greenhouse bioassay for this pathosystem. This is indispensable for banana phenotyping, particularly since the occurrence of tropical race 4 (TR4), which is a significant threat for the global Cavendish-based banana export industry. Using a double-pot system, hardened 3-months-old tissue-culture plants of ‘Grand Naine’ (AAA, Cavendish subgroup) were individually inoculated with three TR4 isolates and one race 1 isolate with known pathogenicity on ‘Silk’ (AAB) bananas. All TR4 isolates caused similar symptoms and no differences regarding incubation period or severity were observed. In addition, all TR4 isolates were successfully recovered from the symptomatic rhizomes on Komada medium.