Development of in vitro techniques for the elimination of cucumber mosaic virus from banana (Musa spp.)

Bananas and plantains (Musa spp.) are threatened by various pests and diseases, including a number of important viral diseases which represent a constraint on banana production and on germplasm movement from country to country. The latter is especially important for farmers who are waiting to benefit from pest- and disease-resistant varieties, either naturally occurring germplasm or improved varieties produced by breeding programmes or by mutation techniques, as produced in the framework of the IAEA Co-ordinated Research Programme. INIBAP has therefore been very active in establishing a system for the safe international movement of Musa germplasm using different virus-indexing centres (South Africa, Australia and France). At present, about 25% of the International Musa Germplasm Collection maintained at K.U.Leuven (Belgium) by INIBAP, and in particular a significant number of potentially important and improved varieties from breeding programmes, are infected with viruses. Most of this germplasm is infected with BSV but also with CMV, BBTV, BanMMV and BBrMV. To make these accessions available, a programme of virus elimination is currently carried on in the Plant Pathology Unit (FUSAGx, Belgium) in collaboration with the Laboratory of Tropical Crop Improvement (K.U.Leuven, Belgium). Different in vitro techniques, such thermotherapy, chemotherapy, electrotherapy or meristem culture, as well as more innovative ones, such as cryotherapy, were tested for their virus elimination capacity. For this, Williams BSJ banana plants (AAA) mechanically infected with CMV were used. Initially, the health status of regenerated material was checked on in vitro plants through ELISA. The putative virus-free material was then tested a second time after greenhouse acclimatisation.