Intra-clonal variation for essential oil content and composition in plants derived from leaf cuttings of rose-scented geranium (Pelargonium sp.)

Abstract

Significant intra-clonal variation was found for essential oil content and its composition in a small number (75) of plants obtained from leaf (leaf + petiole) cuttings of a vegetatively propagated rose-scented geranium (Pelargonium sp.) cultivar, 'Bourbon'. No intra-clonal variation was, however, found for morphological traits. Variants for essential oil composition included plants with isomenthone as the major constituent (66%), instead of citronellol and geraniol, the key constituents of geranium oil, and plants with negligible amounts of 10-epi-γ-eudesmol, a key constituent used in differentiating commercial geranium oils. The essential oil of one of the variants, with a citronellol/geraniol ratio of approximately 1.4:1 and a significantly higher content of citronellyl formate than the parental cultivar, appeared to be different from the reported commercial geranium oils. Evaluation of the clonal progeny of variant plants revealed the stability of variants through clonal generation of multiplication. The significance of the observed intra-clonal variation in genetic improvement of exclusively vegetatively propagated cultivars of rose-scented geranium is discussed.