Mutagenesis In Banana

M Azhar* and I Rusli

Malaysian Institute for Nuclear Technology Research (MINT), Bangi 43000 Malaysia and *University of Leicester, LE1 7RH UK
Back to Kews Plant Genome Size Meeting Papers

Abstract


    One of the promising strategies for banana improvement is through mutation induction that has been proven to alter one or more characteristics of plant cultivars, while retaining advantages of the original genotype. At the Malaysian Institute for Nuclear Technology Research (MINT), gamma irradiation for acute mutagenesis has been utilized with shoot tip cultures since 1992 through collaboration with other local universities, institutions and private companies. We targeted the improvement of a popular local desert banana, Pisang Berangan, with the aim of inducing genetic variations and further selection for disease tolerance, especially to Fusarium wilt. This approach is very important for vegetatively-propagated plants and sterile Musa accessions (2n = 3x = 33), which have a haploid 1C genome size of about 550 Mbp, since sexual reproduction is not available to recombine variation. Previous work done at different ploidy levels had shown that the most effective doses for the induction of useful mutations are between 20 and 60 Gy. Some selections of gamma-irradiated Pisang Berangan appeared promising for tolerance to Fusarium wilt, but screening and confirmation are needed. Consequently, by 2004 a new "Gamma Greenhouse" facility, which makes use of chronic irradiation, will be operated. It is considered to be more effective in recovering and producing useful mutants in comparison to acute irradiation. Isolation of mutants is necessary and is the first step in any breeding programme to provide advantageous material. However, in vitro mutagenesis of multi-cellular cells leads a high degree of chimerism, producing unstable mutants. Hence, there is an urgent need for a tool to identify mutants using molecular assisted markers,l as the promising mutants can be identified, propagated and screened at tissue culture level. Thus, the next step to be focussed upon is to exploit the large insert DNA libraries (BACs) for the genome study in order to search a universal marker(s).