Pre-Screening of Banana Genotypes for Fusarium Wilt Resistance by Using an In Vitro Bioassay

AbstractIn the process of breeding and selection of banana for resistance to Fusarium wilt, it is important to conduct an efficient resistance screening test by artificial inoculation withFusarium oxysporumf. sp.cubense(Foc) Tropical Race 4. So far, there are two types of early bioassays for screeningMusagenotypes against Foc: a greenhouse and anin vitrobioassay. The most commonly used greenhouse bioassay is a pot-based system followed by a hydroponic system. Here we describe anin vitrobioassay characterized byin vitroinoculation of rooted banana plantlets grown on medium consisting of half-strength MS macronutrients and MS micronutrients. The disease response and evaluation results obtained through thisin vitrobioassay correlates with that from a greenhouse screen and/or field evaluation. Given the importance ofin vitrocell and tissue culture techniques for banana (mutation) breeding, promising resistant clones could be screened directly. Thisin vitrobioassay is a totally contained system compared with greenhouse methods and does not require an acclimatization step, thereby improving banana breeding efficiency. Thein vitropre-screening protocol and bioassay for Fusarium wilt resistance presented here is fast, space-effective, and accurate.