Genetic diversity and sectional relationships from an amplified fragment length polymorphism analysis of Taiwan bananas

Phylogenetic relationships among 19 Musa species or cultivars were examined through DNA fingerprinting with amplified fragment length polymorphism (AFLP) analysis. The AFLP analysis was performed on the Musa species or cultivars with 21 primer combinations, yielding a total of 6,348 DNA bands, among which 6,113 (96.3%) were polymorphic. M. itinerans var. formosana demonstrated 133 monomorphic bands, which is the most among all samples. Unweighted pair-group method with arithmetic averages was used as a cluster program to divide M. itinerans, M. acuminate, M. balbisiana and 16 cultivars into different major groups. The genetic similarity coefficient among all the species was 0.23. Bananas with the A genome were clustered into the same major group. The similarity coefficients of 'Pei Chiao' with 'Giant Cavendish' (0.99) and 'Dwarf Cavendish' (0.97) indicated that these cultivars share a strong phylogenetic relationship. Within the primer combination of E-TAC/M-GTC, the fingerprint pattern of 'Pei Chiao' was compared with that of 'Giant Cavendish' and 'Dwarf Cavendish' to show two polymorphic bands of 255 and 238 bp. Although 'Pei Chiao' with the AAA genome was highly similar in genetic constitution to 'Giant Cavendish' and 'Dwarf Cavendish', it still can be discriminated from its close relatives according to the information of few polymorphic fragments. In addition, the phylogenetic analysis results revealed that the genetic organization of native Taiwan species, M. itinerans var. formosana, differed significantly from that of the other banana species. The findings of this study may facilitate germplasm identification and genetic breeding of banana species and cultivars.