Ploughing and sowing depths may not only be responsible for good emergence of seed but could also be responsible for stronger stalk and stem girth, it is therefore necessary to investigate effect of depths of tillage on some yield and yield components of yellow maize (Zea mays) hybrids. The land was divided into eighteen compartmental plots of 400 m2 each comprising 2 tillage depths (0-15 cm and 15-30 cm), 3 hybrids (HYB 2, HYB 4, HYB 6) at 3 replicates each to make 2×3×3 factorial design. Each plot measured 4 m × 10 m at 2 m apart from each other. The power tiller was made to maintain uniform speed throughout the operation in each case as the mouldboard ploughs were adjusted for the required depths. Among the data collected were days to emergence of seeds, plant height, number of leaves/plant, days to anthesis (DAT), days to silking (DAS), Anthesis-Silking Interval (ASI), Leaf Area Index (LAI) and grain yield (GY) yield/plant. Among the characters of selected maize association with anthesis to silking interval (0.32), 50% of anthesis (0.32) and also yield (0.33). Results showed that grain/yield depicted a highly significant position association with number of leaves (0.32), 50% tasselling (0.36) and 50% silking (0.33). Inter-character association revealed that anthesis to silking interval displayed highly significant association with days to silking (0.32) and also a highly significant negative association with 50% anthesis (-0.26). Yield had highly significant correlation with number of leaves, days to 50% tasseling, days to 50% silking. Inter-character association revealed that number of leaves had positive association with plant height and leaf area index.
Key Words: Emergence of seed, Mouldboard Plough, Plant height, Power tiller, Stem girth