Effect of Age at Harvest and Leaf Position on the Yield and Nutritional Composition of Celosia argentea L.

A pot experiment was carried out at the nursery site of the Department of Crop Production, Federal University of Technology, Minna (9°36’ N, 6°33’ E) Niger state, Nigeria. The study aimed at determining the effect of age of celosia plant at harvest on the yield and nutritional composition of the plant as well as the concentration of nutrients at different leaf positions. The experiment was a 3 x 3 factorial combination of three harvest periods (5, 7 and 9 weeks after sowing) and three leaf positions on the mother plant (upper, middle and basal) arranged in a completely randomized design. Harvested leaves were analyzed for the nutritional composition. The results showed that the whole plant fresh weight, varied significantly (p<0.05) with the age of plant at harvest, having the maximum and the minimum values at 9 weeks after sowing (266.19 g/pot) and 5 weeks after sowing (96.12 g/pot) respectively. The leaf fresh weight and leaf dry weight followed the same trend with the whole plant fresh weight. Crude protein and Na reduced significantly (p<0.05) with the age of the plant with the highest values recorded at 5weeks after sowing. Zn was highest at 7 weeks after sowing. K and Vit. C content were significantly higher at 9 weeks after sowing. Ca was highest at 9 weeks after sowing but there was no significant difference in the value obtained at 9 and 5weeks after sowing. Higher values of Fe were obtained at 7 and 9 weeks after sowing. The Mg content was not significantly affected by the age at harvest. The middle leaves had significant higher content of Mg and Vit. C when compared to the basal leaves but there was no significant difference between the values obtained in upper and middle leaves. Significant (p<0.05) higher values of Ca, Fe, and crude protein were recorded in the basal leaves. There was no significant difference in the values of K, P, Na, Fat and Zn obtained at the different leaf positions.