Abstract
In order to investigate the effect of plant density on the essential oil content and yield of four basil landraces collected from Esfahan, Fars, Tehran and Khorasan, an experiment was conducted in Bam, Iran in 2011. The experiment was carried out as a split plot based on a Randomized Complete Block Design with four replications. Treatments included four plant densities (7, 9, 13 and 22plants per m2) as main plot factor and four basil landraces (Khorasan, Tehran, Esfahan, Fars) as subplot factor. The results indicated that Esfahan landrace at all plant densities, Fars landrace at the plant densities of 22 and 9 plants per m
2, Khorasan landrace at the plant densities of 22, 13 and 9 plants per m
2 and Tehran landrace at the plant density of 13 plants per m
2 had the highest essential oil yield. The landrace and plant density interaction was significant for leaf dry matter yield, essential oil content and essential oil yield. Esfahan landrace at the plant densities of 7 and 9 plants per m
2 and Khorasan landrace at the plant density of 7 plants per m
2 had the highest essential oil content (0.78%). The lowest essential oil content in Fars (0.45%), Esfahan (0.43%) and Tehran (0.41%) landraces was obtained at the plant density of 22 plants per m
2. In Esfahan landrace, the increased leaf dry weight at the higher plant densities was so high that compensated for the lower essential oil content and finally the essential oil yield at the all plant densities of this landrace gained the highest values (6.8-8.6 kg/ha).