UTILIZATION OF WEEDS AS BIOLOGICAL RESOURCES AND AS A MANAGEMENT TOOL

Although weeds are considered undesirable or troublesome plants, many weeds and their relatives, occurring on mountains, disturbed habitat and on arable lands, are very important for us to use as good natural resources. In Korea, native plants, and/or weeds were found to belong 185 plant families, and included 1,065 genera, and 4,596 species in total. Some of these weeds have medicinal uses; others are edible, and still others possess dyeing properties. Colonizing plants can be used to remove environmentalcontaminants, raw materials for ethanol bio-fuel, and as sources for phyto-chemicals and allelopathic chemicals. Allelopathic phenomena may also be increasingly used in the field, for weed suppression. Recent reviews indicate extensive and similar uses of weeds, which have been reported from many Asian countries. Of the major avenues of utilization, the use of colonizing plants to remove environmental pollutants, their use as bio-fuel sources and the exploitation of their allelopathic potential are all receiving significant attention in the Asia-Pacific Region. Weeds or their relatives have a variety of genetic diversity from which useful genetic resources, such as a gene(s) for functional substances can be derived and introduced into cultivating crops. Some plants, such as wild oat (Avena fatua L.) and spotted knapweed (Centaurea maculosa Lam.) have a strong allelopathic potential or parasitic ability by which neighboring plants are completely controlled. Strategies for isolating and characterizing functional substances could be employed for economic exploitation of weeds. Genes coding for the functional substances should be cloned and introduced into cultivating crops for developing a new genotype. Future efforts in Weed Science should not ignore the various possibilities of utilization of weeds or their relatives as biological resources increased exploitation of colonizing species will be a useful management tool for some species, which are currently considered problematic.