Diversity of the genus Ocimum (Lamiaceae) through morpho-molecular (RAPD) and chemical (GC–MS) analysis

Abstract

In this present study, we have described the diversity of nine <i>Ocimum</i> genotypes naturally grown in the Dakshin Dinajpur district of West Bengal, India. Their diversity was determined on the basis of morphological, chemical and randomly amplified polymorphic DNA (RAPD) to determine the level of variation present in the genus <i>Ocimum</i>. Among nine <i>Ocimum</i> genotypes six (<i>O</i>. <i>americanum</i>, <i>O.</i> × <i>africanum</i>, <i>O. basilicum</i>, <i>O. gratissimum</i>, <i>O. kilimandscharicum</i> and <i>O. tenuiflorum</i>) are found to be different <i>Ocimum</i> species and the rest are as varieties. A total of 18 qualitative and 17 quantitative morphological traits and chemical compositions were evaluated. Significant variations were observed in the morphological traits except <i>O.</i> × <i>africanum</i> and <i>O. basilicum</i> species. Cluster generated from the morphological data showed two different groups <i>viz</i>. basilicum group and sanctum group. Chemical analysis did not show much variation between morphologically similar species <i>viz</i>. <i>O.</i> × <i>africanum</i> and <i>O. basilicum</i>. However, RAPD analyses clearly showed that <i>O.</i> × <i>africanum</i> and <i>O. basilicum</i> are different species. Thus the combined analyses of morphological traits, chemical and molecular markers represent the best possible approach to confirm taxonomic delineation. Moreover, we are reporting <i>O.</i> × <i>africanum</i> for the first time from this region as well as from West Bengal, India.