Lab-Based Screening Using Hydroponic System for the Rapid Detection of Fusarium Wilt TR4 Tolerance/Resistance of Banana

Abstract

Field-based screening and evaluation of banana plant tolerance or resistance to Fusarium oxysporum f. sp. cubense (Foc) Tropical Race 4 (TR4) or also known as Fusarium wilt TR4 is ideal though not always feasible. Alternatively, screening of banana plantlets at lab-stage seems to be an effective method for early detection of Foc TR4 tolerance. We present a simple hydroponic system, that allows plant to grow in a water-based condition. The system has two layers, the upper layer is a tray that has holes for plantlets to be placed where the root system is supported using an inert medium such as rock-wool. The lower layer is a perforated container filled with a water-based nutrient solution. For this lab-based screening, ex vitro gamma irradiated banana cv. Berangan (AAA) rooted plantlets with a pseudostem height of 10–15 cm were inoculated by soaking in a Foc TR4 conidial suspension (10 ⁶ spores/ml) for 2 h under room temperature. The Foc TR4 inoculated rooted plantlets were screened using the hydroponic system and disease symptoms were scored. In this chapter, protocols on acclimatization of ex vitro irradiated rooted plantlets, inoculation with a Foc TR4 conidial suspension, lab- screening using hydroponic system, observation for early detection of disease symptoms and scoring of disease severity are presented.