Field experiment was conducted at the International Institute of Tropical Agriculture Ibadan and Ikene substation during the 2012 rainy season to study the effect of variety, Nitrogen fertilizer Rates on the growth and yield of four yellow cassava varieties. Four (4) IITA yellow cassava varieties (IITA TMS01/1412, IITA TMS 01/1368, IITA TMS 01/1371 and IITA TMS 01/1593), 3 fertilizer rates (0kg/ha, 400kg/ha and 600kg/ha) and one mineral fertilizer NPK15:15:15 was tested using a split-split plot experimental design, with three replications. Data collected were analyzed using Least Significant Difference. The variety TMS01/1412 significantly (P≤0.05) produced highest fresh tuber yield of (9.90tons/ha) and (9.66tons/ha) in both Ibadan and Ikene respectively. The varieties significantly (P ≤0.05) differ in fresh tuber yield and dry matter content, while IITA TMS 01/1593 significantly (P <0.05) produced highest dry matter content (33.90%) and total carotene value (7) of all the yellow cassava varieties in both locations. It was concluded, that the variety TMS01/1593 produced higher total carotene content and dry matter content at 0kg/ha of NPK Fertilizer in both locations. It could therefore be recommended for cultivation in Ibadan to enhance vitamin A content and increase the quantity of cassava products, while TMS01/1412 can be cultivated in both Ibadan and Ikene to obtain a high fresh tuber yield. A further research is recommended to determine the appropriate fertilizer type and rate of application.

Keywords: Yellow cassava, Total carotene, Fresh tuber yield, Crystallizer fertilizer,