Evaluation of Morphological Characteristics, Yield Potential, and Essential Oil Composition of Ocimum sanctum Genotypes for Crop Improvement

Abstract

Ocimum sanctum, also known as Holy Basil, is an aromatic herb with a long history of use in traditional medicine. It is native to tropical and subtropical regions of Asia and is now cultivated worldwide. Plants have erect, much-branched sub-shrub with simple opposite green or purple leaves that are strongly scented and hairy stems and leaves has a strong, characteristic aroma that occurs mainly because of the volatile oils present.
 In this experiment, 30 genotypes of Ocimum sanctum were evaluated for morphological, yield and quality traits. At nursery stage, germination percentage, seedling shoot length and seedling root lengths were recorded. Among the accessions. OS-22 exhibited the highest germination percentages (82%), Seedling shoot and root length were highest in Os-18 and OS 21 (35 cm and 11 cm) respectively. In the main field, the accessions were characterized for qualitative traits viz growth habit, leaf colour and stem colour. The accessions were grouped into two, based on growth habit. Based on stem and leaf colour the accessions were grouped into five and four groups respectively. In case of quantitative traits, plant height achieved maximum in the accession OS 22 (88cm) followed by OS 17(75cm). The accessions OS-15 and OS-22 exhibited more extensive plants spread, while OS-21 and OS-13 had higher number of primary branches. Accessions OS-20 and O S-23 recorded more number of leaves (409 and 422) and the accessions O S-22 and OS-11 recorded highest fresh leaf weight (370.2 g & 301.67 g). The essential oil recovery and oil yield was highest in the accession OS 20 (green type) followed by OS 22 (purple type). Characterization of oil in GCMS revealed that the key component was eugenol, which showed highest content in accession Os-20 (46 %). This study can be used for further crop improvement studies and breeding programs.