| dc.description.abstract | The distribution of Pythium species across land use gradient was examined in two agroecological
zones in Kenya. The two zones were selected owing to their unique characteristics and locations.
Soil samples were collected along a transect from the forest through to the cultivated land. The
sample plots were established at fixed intervals of a distance of 200m apart to avoid autocorrelation
Pythium propagules were activated to germination using baiting techniques, and the
mycelium baited was cultured to obtain axenic culture for identification. Based on morphological
characteristics, a total of 32 species of Pythium were found at the Embu study site, with soil
under Napier having the most diverse population and that under maize the least. The Taita site
yielded 12 Pythium species, with the highest diversity in cropped plots and the lowest in Natural
forest. Species abundance increased with increasing ecosystem disturbance while diversity
increased with decrease in disturbance. All the species isolated from the Taita site were also
sampled from the Embu site except P. helicoids, P. periplocum and P. grandisporangium. The
common pathogenic species P periplocum, P. hypogynum and P. spinosum were isolated mostly
from croplands confirming the effect of host occurrence on the distribution of Pythium species. | |
