Somaclonal Variation in Banana: Cytogenetic and Molecular Characterization of the Somaclonal Variant CIEN BTA-03

Variability in a given banana population has several advantages when biotechnology 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 Cavendish), 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 variant detected through cytogenetic analysis, relative nucleic acid content estimated by flow cytometry and random amplified polymorphic DNA (RAPD) analyses, are described. The most significant mutational event observed in the variant was an increase of the chromosome number. The results show that CIEN BTA-03 is a tetraploid clone, demonstrated by cytogenetic, flow cytometry and RAPD markers. Additionally, our results suggest that CIEN BTA-03 is not part of the Cavendish subgroup to which the parental Williams (AAA) belongs.