Comparative Morphophenological studies and genetic improvement in Ocimum Basilicum Var Purpurascens Benth. (Lamiaceae) through induced autopolyploidy

Abstract

Colchiploids of Ocimum basilicum var purpurascens Benth (Lamiaceae), a herb of high medicinal and commercial value, yielded significant results with regard to various morphophenological characters, such as root-stem ratio, branches, leaves, inflorescence, fresh and dry weights of different parts, biomass, height, seed, etc. Secondary branches bearing leaves increased from 2.5 per primary branch in the third generation autopolyploids (C2). Total leaf area (total number of leaves x area of a leaf) produced by C1 plants also considerably improved from 10884.60 cm2 to 29308.70 cm2. Various characters of the inflorescence and an important source of phytochemical constituents in addition to leaves, such as total number and length of inflorescence, the total number of floral whorls in an inflorescence, diameter of a floral whorl, and length between two whorls improved a lot in C2 herbs. Also, biomass, height at different stages of growth and seed output, its weight, germination percentage, etc. showed a significant increase. After an initial decline in C0 and C1 plants, an overall improvement in the above characters was clearly noticed in C2 colchiploids of the herb understudy. Commercial exploitation of the plant thus produced is therefore recommended.