Intersectional relationship between EuMusa and Rhodochlamys of the genus Musa using morphotaxonamy and microsatellite markers.

Abstract

The genus Musa of the family Musaceae has been classified into four sections, i.e. Eumusa, Rhodochlamys, Callimusa and Australimusa. Eumusa members have contributed considerably to the evolution of present-day bananas. Rhodochlamys members, which are very close to the section Eumusa and more specifically to Musa acuminata, have a wide distribution in the Indian subcontinent. This paper deals with a detailed assessment of intersectional relationships between 24 accessions from Eumusa, Rhodochlamys and hybrids of Eumusa x Rhodochlamys, using morphotaxonomic and molecular characterisation. All the test accessions were morphotaxonomically characterised and documented. A total of 21 primer pairs were used to assess the microsatellite polymorphism, of which 81% amplified products, resulting in discrete, reproducible amplicons. A total of 145 alleles were identified with a mean of 8.05 alleles per primer pair. An average PIC of 0.55 was observed. The developed dendrogram failed to project a clear-cut distinction between Eumusa and Rhodochlamys members, indicating a close genetic make-up. Diversity analysis suggests that 'Matti', a Eumusa member, could be a parthenocarpic derivative of M. acuminata ssp. burmannica. Four M. acuminata wild forms identified from North Eastern India during recent explorations proved their uniqueness but exhibited higher genetic relatedness to Rhodochlamys. Musa laterita and its progenies grouped in the same cluster in both morphotaxonomic and molecular characterisation, indicating their close genetic make-up.