No abstract. The following is the author's introduction:
1. 1 Project's justifications: Allelopathy (usually confused with competition) is a young science which is not known by many people especially in developing countries and therefore needs to be explored. There is some evidence that crop species can have allelopathic ability. For example, it has been proved that exudates from barley (Hordeum vulgare) roots reduced the growth of Stellaria media (chickweed) grown in vermiculite (growth medium) and also reduced its germination (Newman, 1982). Its knowledge gives you an idea of the plants which one can rotate or intercrop. Sunflower (Helianthus annuus) is widely grown in Namibia on a small scale, but there is potential for it to be popular and to be grown on a large scale in the near future. Pearl millet \{Pennisetum glaucum) is one of the main crops in the Northern part of the country. Pigweed (Amaranthus palmeri), one of the main weeds is allowed to grow with crops like pearl millet since farmers use it as a local spinach. If an allelopathic interaction between pigweed and pearl millet is found, it could lead to a modification of this practice
1. 2 Objective of the project: To investigate the allelopathic interactions among pearl millet, sunflower and pigweed
1. 3 Research questions: (a) Is the growth of either pearl millet or sunflower inhibited by root extracts of pigweed? (b) Is the growth of pigweed inhibited by root extracts of either pearl millet or sunflower?
