Somaclonal variation for some morphological traits, herb yield, essential oil content and essential oil composition in an Indian cultivar of rose-scented geranium

Somaclonal variation for plant height, plant spread, leaf shape, leaf size, leaf form, herb yield, essential oil content and 10 important constituents of the essential oil was studied in an Indian cultivar, 'Bourbon' of rose-scented geranium (Pelargonium graveolens). Significantly larger variance was observed among in vitro-regenerated plants of the SC1 generation (first generation following an in vitro phase) than among parental plants raised from stem cuttings for herb yield, plant height, leaf size, essential oil content, and for the contents of cis-rose oxide, trans-rose oxide, isomenthone and 10-epi-γ-eudesmol in the essential oil. Plants of the SC1 generation showing values beyond the higher or lower limit (depending on the trait) of the range observed among parental plants for different traits were developed into clones by their multiplication through stem cuttings, and evaluated again in the SC2 generation (second generation following the in vitro phase). Somaclones selected for plant spread, and for the contents of linalool and trans-rose oxide in their essential oils did not breed true in the SC2 generation. However, for the remaining traits studied, 13-100 of the selected clones retained their selected traits in the SC 2 generation, suggesting that the changes in these somaclones were due to genetic causes