Aerial parts of Ocimum basilicum var. purpurascens Benth, Ocimum basilicum var. dianatnejadii Salimi at flowering stage were collected from plants grown in Experimental Station of Pykan Shahr, near Tehran. Elevation 1215 m above sea level, latitude 35° 42′ North, 51° 8′ East, average humidity 36% and climatic category semi-arid.

Methyl chavicol (43.0%) and linalool (28.9%) were identified as the major compounds in the oil of O. basilicum var. purpurascens, while methyl chavicol (37.6%), linalool (33.4%) and alpha-cadinol (5.7%) were the major constituents in the oil of O. basilicum var. dianatnejadii.

MATERIAL AND METHODS: The study was separated in two experiments performed in our research station Campus Rural of The Federal University of Sergipe (UFS), Sao Cristovao city, Sergipe State, from December 03, 2002 to April 28, 2003. First harvesting: The first harvesting (Experiment 1) was performed 40 days after seedlings transplantation during full bloom on 03/06/2003. Harvesting was performed cutting plants at 20 cm height from the soil. The collected material consisted on separating leaves and inflorescences from the stalk. In the first experiment only used leaves in the analysis. Randomized block design in a 3x4 factorial scheme with three replications was used. Each plot was composed of five plants. Treatments were: three harvesting periods (8:00; 12:00, and 16:00 h) combined with three drying temperatures (40, 50, and 60 ℃) and fresh leaves. Second harvesting: To perform the second harvesting (Experiment 2) we collected the regrowth of plants used in Experiment 1. Plants were harvested fifty three days after the first harvesting (on 04/28/2003) at 8:00 h using the same procedures as the first one; however both leaves and infl orescences were used in the analysis. Randomized block design with three replications was used. Treatments were drying periods of 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, and 16 days for leaves and infl orescences in ovens with air renewal and circulation (Marconi model MA-037/5) at 40 ℃.

Harvesting performed at 8:00 h and 12:00 h provided higher essential oil yield. After five days drying, the concentration of linalool raised from 45.18% to 86.80%. O. basilicum should be harvested during morning and the biomass dried at 40 ℃ for five days to obtain linalool rich essential oil.

The 36 'Genovese' and 24 'Foglia di Lattuga' samples preliminarily analysed were grown in Tavazzano (MI), and harvested at flowering, from 5th to 10th August 1998. The breeding program started in 1999, by crossing several selected lines of 'Genovese' with 'Foglia di Lattuga' and 'Compatto'. Selected F1 plants were selfpollinated in 2000. Plants of the F2 (2001), F3 (2002) and F4 (2003) generations were selected on the basis of agronomic and morphologic traits, and self-pollinated. Only the seeds from self pollinated plants with satisfactory essential oil content and composition were used to obtain the next generation. In 2004, some F4 plants were replanted in order to evaluate their stability in relation to environmental variations. All leaf harvests were carried out at flowering.

Genovese' showed higher essential oil and linalool content, with almost total absence of methyl chavicol, very abundant in 'Foglia di Lattuga'.