Characterization of Ocimum tenuiflorum (Linn.) Morpho-types Using RAPD Markers

Ocimum tenuiflorum Linn. (Lamiaceae) is an aromatic plant with a lot of potential medicinally, industrially and domestically. There are different morpho-types of O. tenuiflorum, with different shades of purple pigment on their leaves. Very few studies have been done to study the genetic variation among O. tenuiflorum morpho-types. Thus, in the present study, four O. tenuiflorum morpho-types that varied in pigmentation were characterised using RAPD marker as a molecular tool. Eight different primers collectively amplified 64 bands in the four morpho-types analysed. The RAPD technique revealed that the varied amount of purple pigment in O. tenuiflorum morpho-types is not due to environmental factor alone. The UPGMA clustering algorithm based on RAPD data grouped the four morpho-types into two major groups, with O. tenuiflorum (T2) with very light purple leaves and stem morpho-type, more related to O. tenuiflorum (T3) that have deep purple leaves and stem. The result was able to show the phylogenetic relationships within the species. The low level of genetic diversity observed in O. tenuiflorum can be attributed to the mode of reproduction and the reproductive biology of the species, due to the fact that they are likely to be natural hybrids produced through cross pollination.