Chemotypic characterization and development of morphologicalmarkers in Ocimum basilicum L. germplasm

Abstract

tSignificant variations are observed in the content and composition of the essential oils obtained from dif-ferent Ocimum species based on their distinct morphological characters and harvesting seasons. Variousgermplasms of Ocimum basilicum grown in India were compared for the essential oil content and compo-sition to identify the superior germplasm rich in desirable chemical components, such as methyl chavicoland eugenol, that could be exploited for commercial cultivation in western plains of India. The essentialoils were extracted using hydro distillation and chemically characterized on Gas Chromatograph–massspectrophotometer (GC–MS). Colour of the leaves varied from green to purple-green with bunchy, indi-vidual and intermediate type of panicles. Maximum oil per cent in leaf was observed in DOB-1 (0.70%),followed by DOB-5 (0.61%) at stage II. Leaves harvested at stage II gave higher essential oil yield thanharvested at stage I. The content of methyl chavicol increased at full flowering (stage II), while contentof Eugenol and methyl eugenol increased at onset of flowering (stage I). Majority of the germplasm werefound to be rich in methyl chavicol, except DOB-4 which was rich in methyl cinnamate. The intensity ofpurple leaf colour was observed to be positively correlated in lines rich in methyl chavicol. Maximummethyl cinnamate (DOB-4) content, leaf size and average minimum plant height were found positivelyrelationship. Such relationship has become a key factor field nose needs to be properly understood andsuperior lines DOB-1 and DOB-5 further used in improvement programme.