Response of Imperata cylindrica (L.) weed Seeds germination to some environmental factors

Halfa or cogongrass (Imperata cylindrica L.) is one of the noxious/problematic species which not only threatens agriculture productivity, but also causes environmental damage to the ecosystem, whereas the invasive alien weeds are affected greatly by seed germination that depends on the temperature and light as well as other environmental factors. Therefore, the germination behavior of I. cylindrica at the optimum temperature regimes (25/35 °C) was chosen to test the effect of different light regimes, some growth regulators i.e. indole butyric acid (IBA), gibberellic acid (GA3), and naphthalene acetic acid + naphthalene acetamide (NAA + NAD), and chemical substances i.e. Potassium nitrate (KNO3) and Si-Si-6, acetic acid on seed germination of cogon grass (I. cylindrica). The higher germination percent of I. cylindrica seeds was observed after soaking for 12 hours in the growth regulators at 200, 800, 400, and 1000 ppm which exhibited germination of 56.67, 71.11, 73.33, and 56. 67% after soaking in gibberellic acid and 65.56, 71.11, 73.33, and 56.67% after soaking in indole butyric acid, respectively under 16/8 hours of light/darkness. The maximum germination of I. cylindrica seeds (22.44%) was also achieved after exposure to 1% acetic acid for 1min. under 16/8 h light/ dark and the same temperature, while the greater level of germination (55.56% and 35.56%) was attained after 12 h. soaking in 10% from Si-Si-6 (Potassium sulphonate 10% SL) and KNO3, respectively. It can be concluded that I. cylindrica germination rate depends on the environmental factors and its time of exposure which are the driving force for changes in I. cylindrica seed dormancy. This information could help in preventing and predicting their invasion as well as may lead to improving its management strategies.