Molecular analysis of variants identified from orchards growing with micro propagated Robusta banana (Musa spp. ‘AAA’) using RAPD markers

Abstract

The molecular fingerprinting using RAPD markers of thirteen morphological variants (off-types) and a normal from farmers' field planted with micropropagated Robusta banana (Musa spp.) and Robusta and Grand Naine clones from authenticated source was carried out. Out of fourteen arbitrary (10-mers) primers showing intense unambiguous and reproducible amplification using PCR, two primers viz., OPA-19 and OPC- 03 showed only monomorphic bands while OPA-02, OPA-09, OPA-13, OPA-14, OPB-6, OPB-15, OPC-01, OPD-10, OPF-04 and OPF-12 primers showed polymorphic amplification pattern. Out of 123 amplified fragments scored, 53 fragments were polymorphic in nature. In addition, a dendrogram generated based on Ward's method of cluster analysis revealed that all morphological variants grouped into a cluster that was separate from the other cluster which consisted normal plant from field, Robusta and Grand Naine. In the genetic dissimilarity matrix generated based on Squared Euclidean Distance, 20-35 percent variation between morphological variants and normal plant was noticed in 'Extra dwarf plant with pseudo stem' and 'All foliage plant' (35%). The field plant showed genetic variation of 5% from somaclonal variants of 'Robusta' clone, while that variation has not affected its morphology as well as fertility. Results showed that morphological variations in field planted micropropagated Robusta plants were due to somaclonal variations, which suggests that the need for use of molecular means in commercial tissue culture units for testing genetic fidelity of plants as a safety measure to avoid passing of off-type planting material to farmer.