Genetic and chemotypic variability in basil (Ocimum basilicum L.) germplasm towards future exploitation

The present investigation was conducted to estimate the genetic diversity in Ocimum basilicum germplasm consisting of sixty accessions using Mahalanobis D-2 analysis. All the Ocimum accessions were grouped into seven diverse clusters and there was no parallelism observed between the genetic divergence and geographical origin. Maximum inter cluster distance was found between cluster II and cluster VII (200.71) and minimum between cluster I and II (26.61). Among the nine economic characters, leaf area was found to be the major contributor towards genetic divergence (16.01%) followed by oil yield (15.12%); however, the lowest contributing character was plant height (4.26%). Chemical characterization of the accessions was also carried out based on the percentage of different components of the essential oils present in them. A six-membered cluster exhibited the maximum content of methyl chavicol in the essential oil. Some accessions were found to be highly rich in linalool and can be used for selection of linalool rich chemotype/lines. Some accessions exhibited linalool along with methyl cinnamate. An accession OB 28 was found to be rich in methyl cinnamate and methyl eugenol. Therefore, new chemotypes of Ocitnum can be exploited in the hybridization program possessing different combinations of essential oils.