The Classification of Musa L.Based on mtDNA ccb256 Sequence
The phylogeny and relationship among 42 accessions were investigated by analyzing DNA sequence obtained from mtDNA cytochrome c biogenesis orf256(ccb256).The phylogenetic tree was constructed following maximum parsimony(MP)method using MEGA4.The results indicated that Australimusa and Callimusa section grouped together;AA and other species from Eumusa clustered with Rhodochlamys section.BB species from Eumusa section were placed a outgroup which revealed its primitive position in evolution of Musa L.In addition,Ice cream(ABB)and M.balbisiana formed one group which showed that M.balbisiana may be male parent providing B genotype for Ice cream.Except for Improved lady finger(AAB),other cultivated accessions and M.acuminata formed a group.It was inferred that M.acuminata provided A genotype for these accessions as a paternal plant.M.acuminata.ssp.banksii,which was considered to be the original parent of cultivars,grouped with almost all the cultivated accessions.It had a close relationship with cultivars.The results also showed that ccb256 sequence had a moderate evolutional rate,which should assist in gaining a better understanding of the evolution of wild and cultivated bananas and of the relationships between diploid and triploid bananas.