Qualitative and Quantitative Assessment of Weed in the Major Wheat Growing Areas of Western Oromia Region, Ethiopia

A weed population survey was undertaken  to determine prevalence and distribution of weeds , and asses weed flora shift in major wheat growing districts of western Oromia, namely Getema, Gudeya-Bila, Jima-Arjo, Abay-Coman, Horo and Jima-Geneti. The first three districts are found East Wollega zone and the rests are from Horo-Guduru wollega zone. A totally of 48 wheat fields were assessed using quadrant counts (0.25m -2 ) once at tillering stage of crop.  Result revealed that a total of 51 weed species with 46 weed genera belongs to 19 families were recorded. Graminaea and compositae were most abundant and diversified families based on the number of species recorded.  Individual weed species shown variation in their abundance, dominance and frequency. The most frequent weed species in the wheat fields irrespective of the soil, climate and crop varieties were Acanthuspermum hispidum , Avena fatua, Commelina latifolia, Guizota scarba, Polygnom nepalens, Setaria pumila, Spergula arvense and Trichodesma zeylanicum , and also were considered as the most important species in the surveyed areas.  From Similarity indices variation was noted between locations. Accordingly, districts having similarity indices more than 60% indicating similarities in weed community. Thus, when devising a weed control strategies same control option would be considered for the location that have similar weed flora and vise versa. Keywords: Flora Composition, Similarity Index, Survey, Weed Prevalence, Wheat