The influence of genetic variation on essential oil composition in Rosmarinus officinalis L., the common rosemary

Genetic variation within a species can be reflected in a range of essential oil compositions and concentrations. Elite perennial horticultural crop genotypes are commonly identified using cultivar names. Nine such cultivars (genotypes) of Rosmarinus officinalis L. were grown under homogeneous environmental conditions in the glasshouse. They were treated with an inorganic fertilizer at monthly intervals to promote healthy growth. After eight months the essential oil was extracted by hydro-distillation and the composition analysed using GC-MS and 1H NMR. The main chemical constituents of these essential oils were identified. Significant qualitative differences were found between the cultivars. The cultivar 'Haifa' showed significantly higher percentages of β-pinene (8.06%), camphor (33.26%) and eucalyptol (16.99%), whilst 'f.albflorus', 'Severn Sea' and 'Roseus' contained lowest percentages (0.6%), (7.58%) and (4.15%) for the same compounds respectively. 'Blue Rain' gave significantly the highest percentages of borneol (5.63%) and p-cymene (1.93%) compared with 'Roseus' and 'Primley Blue' which showed (0.2%) and (0.46%) respectively. On the other hand, 'f.albiflorus' outperformed significantly in linalool (2.59%) and myrcene (34.29%) compare with all other contents. The major content of camphene (9.36%) and α-pinene (44.02%) found in 'Fota Blue' and 'Severn Sea' consecutively. However, choice of cultivar should be a primary consideration when growing commercial crops of vegetatively propagated herbs for oil production.