Growth and Essential Oil Yield of African Basil, Ocimum gratissimum, under Light and Water Stress


The growth and essential oil yield of African basil, Ocimum gratissimum L., grown under watered and water-stressed field conditions in full sunlight and natural shade (26.7-44.2% full sunlight) conditions were investigated. Seedlings, 42 days old and growing in a prepared mix contained in plastic bags, were randomly placed in one of four adjoining field plots, one in full sunlight with daily watering, one in full sunlight watered at five day intervals, one in natural shade with daily watering, and one in natural shade watered at five day intervals. Plant height and total leaf area of the African basil were decreased more by water stress than by the light or shade condition. Shade enhanced essential oil content and water stress boosted essential oil content under shade, but reduced oil content under full sunlight. The effects of water stress were only observed in plants in full sunlight. The results demonstrated that African basil will produce relatively high essential oil yields per plant when grown under natural shade, irrespective of water stress and despite poor vegetative growth.