The Effect of Growth Environments on the Growth and Yield of Onion (Allium cepa L.) in Jos, Plateau State, Nigeria

An experiment was carried out between the months of August, 2016 to January, 2017 at the Botanical Garden, Bauchi Road Main Campus, University of Jos, Plateau State, Nigeria, (latitude 09o 511 N and Longitude 08o 531 E and altitude of 1, 159 meters above sea level) to study ‘The effect of growth environments on the growth and yield of Onion (Allium cepa L.) in Jos, Plateau state, Nigeria’’. A completely randomized design in split plots consisting of three onion varieties (Red creole 5, Dan Zaria 1 and Wase) and two growth environments (open field and green house) giving a total of six treatment combinations replicated three times were employed. The parameters assessed include: leaf length, leaf girth (neck), number of leaves, fresh and dry weight of whole plant, fresh and dry weight of bulbs and fresh and dry weight of leaves. The data collected was subjected to analysis of variance and the means were separated using least significant difference (LSD). The result showed that the main effect of variety was significant for the parameters assessed with variety Dan Zaria 1 being significantly (P<0.05) different from varieties Red Creole 5 and Wase. During crop growth, the main effect of growth environment was not significant at initial stages of growth (4, 6 and 8 weeks after transplanting (WAT)) but from 10, 12 and 14 WAT it was significant. The two growth environments did not affect the fresh and dry weight of whole plant at harvest. Onions from the open field resulted in significantly higher fresh and dry weight of bulbs (27.13 and 3.69 g respectively) than those in the green house (19.99 and 2.71 g respectively). Onions grown in the green house had significantly higher (P<0.05) fresh and dry weight of leaves (35.80 and 3.59 g respectively) than those in the open field (25.96 and 2.68 g respectively). There was significant interaction between variety x growth environment on leaf length, leaf girth (neck), number of leaves and fresh weight of leaves. The differences between varieties may be due to genetic variability. Plants in the open field showed a better performance with regards to fresh and dry weight of bulb while plants grown in the green house had higher leaf length and fresh weight of leaves suggesting that green house will give best result for spring onion cultivation, while open field favours bulb production. Keywords: Onions, open-field, green- house, growth, yiel