Research Article of American Journal of Agricultural Research
Seed viability and emergence depths of Ageratum conyzoides L. (Asteraceae)
Ipou Ipou Joseph1*, Gué Arsène1, Touré Awa1& Kouakou Nanan Joseph1
1Université Félix Houphouët Boigny, Laboratory of Botany, UFR Biosciences, 22 BP 582 Abidjan 22, Ivory Coast.
Ageratum conyzoides is a major weed among food crops in Ivory Coast. The viability of its seeds and the depth of emergence of its seedlings were studied in order to understand its distribution and to develop effective management strategies. Generally, less than 50% of the seed of this plant remains viable after one year of soil burial. However, the viable seed rates of this species vary according to depths of burial. The lowest viable seed rates were noted at burial depths of 0 cm and 0.5 cm (5.25% and 8.5% viable seeds, respectively), intermediate rates were at burial depths of 2.5 cm and 10 cm (28% and 26.5% viable seeds, respectively) and the highest rates were at burial depths of 5 cm (43% viable seeds). The highest rates of seedlings of Ageratum conyzoides (75%) were obtained at soil surface. These results indicate that the lifetime of seeds of Ageratum conyzoides depends on their position in the soil. Seed stocks on soil surface are ephemeral while those depths between 2.5 and 10 cm from soil surface may be persistent. For this, after all tillage to a depth of between 2.5 cm and 10 cm from soil surface, regeneration of Ageratum conyzoides must be prevented by destroying raised plants before they reach fruiting.
Keywords: Ageratum conyzoides, Viability of seeds, Seedling emergence