Cultivar selection from rosemary (Rosmarinus officinalis L.) spontaneous population in the Mediterranean area

Rosemary (Rosmarinus officinalis L.) is an aromatic species with a relevant economic value due to its use as fresh condiment or dry spice. Spontaneous populations of rosemary spread in the Mediterranean basin and a high genetic variability is suitable to new cultivars selection for intensive growing management. Few standard cultivars of rosemary are actually available in nurseries and mainly for ornamental use. Furthermore, cultivars are not characterised for biomass quality and chemical composition of the essential oil. The present study is part of a research programme started in 1996, with the aim of characterizing rosemary spontaneous Sardinian populations for their utilization in the selection of new varieties. After mass selection, more than 20 plants were cutting propagated and transplanted in open field for phenotypical characterization. Detailed information on plant morphology, phenology and chemical composition of the essential oils was collected. Data on the 6 most promising cultivars are reported in this note. Plants of 'Gerrei' cultivar showed a very upright habit, while 'Costa Paradiso' was characterised by compact habit and medium vigour. 'Sette Fratelli' plants showed prostrate shape and low vigour, while the highest vigour (highest shoot length and leaf weight) was observed in 'Sant' Antioco' plants. Because of the abundance of 1,8 cineole (15.0%), borneol (17.5%) and bornyl acetate (12.4%) in its essential oil, 'Cala Gonone' genotype resulted different from the others. A high percentage of borneol (26.0%) and bornyl acetate (16.0%) was also observed in 'Costa Paradiso' plants. The 'Vignola' biomass was characterized by the typical essential oil composition of most rosemary selections, with 43.8% of α-pinene as major component. The 'Sant' Antioco' plants were particularly rich in camphor (21.4%) and 1,8 cineole (17.6%), while 'Sette Fratelli' and 'Gerrei' showed abundance of verbenone (above 12.0%).