Allelopathic Effects of Sweet Basil (Ocimumbasilicum L.) on Seed Germination and Seedling Growth of some Poaceous Crops

Laboratory and greenhouse experiments werecarried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15 to study the allelopathic effectsof aboveground parts ofsweet basil (Ocimumbasilicum L.) on seed germination and seedling growth of some poaceous crops.Laboratory experiments were conducted to study the allelopathic effects of aqueous extract of aboveground parts ofsweet basilon seed germination of sorghum (Sorghum bicolor [L.] Moench), millet (Pennisetumglaucum [L.]R. Br.), maize (Zea mays L.) and wheat (TriticumvulgareL.).Six concentrations (0, 20, 40, 60, 80 and 100%) of the aqueous extract of the aboveground parts of sweet basilwere prepared from the stock solution(50 g / l). Treatments, for each crop, were arranged in completely randomized design with four replicates. The seeds were examined for germination at three days after initial germination.Greenhouse experimentswere conducted to study the allelopathic effects of powder of aboveground parts ofsweet basil on seedling growth of the same poaceous crops. The powder of aboveground parts was incorporated into the soil at rate of 0, 1, 2, 3, 4 and 5% on w/w bases in pots. Treatments, for each crop, were arranged in completely randomized design with four replicates. The experiments were terminated at 30 days after sowing and the plant height, number of leaves and root length of crop seedlings were measured as well as plant fresh and dry weight.Data were collected and subjected to analysis of variance procedure. Means were separated for significance using Duncan`s Multiple Range Test at p  0.5. The results showed that the aqueous extract of aboveground parts of sweet basil significantly reduced seed germination of the tested poaceous crops and there was direct negative relationship between concentration seed germination. Also, the results showed that incorporating powder of aboveground parts into the soil significantly decreased plant height and root length of crop seedlings as well as seedling fresh and dry weight. In addition, the reduction in seedling growth was increased as the powder increased in the soil. Based on results supported by different studies, it was concluded that sweet basil has allelopathic affects on seed germination and seedling growth of the poaceous crops.