Somaclonal variation in banana: Cytogenetic and molecular characterizationof the somaclonal variant CIEN BTA-03

Variability in a given banana population has several advantages when biotec hnology is applied in an improvement program. These include the possibility of using systematic analysis or selection techniques to isolate variant or mutant lines with interesting characteristics such as resistance to biotic or abiotic stress. A somaclonal variant of banana CIEN BTA-03 resistant to Yellow Sigatoka. disease was obtained by induction of adventitious shoots from excised sucker shoot tips of Williams cultivar (AAA) (subgroup Cavendi sh), grown in Murashige and Skoog (MS) medium containing 15 mg l(-1) of N-6 -benzyladenine (BA). In this paper, the mutations of the CIEN BTA-03 varian t detected through cytogenetic analysis, relative nucleic acid content esti mated by flow cytometry and random amplified polymorphic DNA (RAPD) analyse s, are described. The most significant mutational event observed in the var iant was an increase of the chromosome number. The results show that CIEN B TA-03 is a tetraploid clone, demonstrated by cytogenetic, flow cytometry an d RAPD markers. Additionally, our results suggest that CIEN BTA-03 is not p art of the Cavendish subgroup to which the parental Williams (AAA) belongs.