Adeyemi, O. R., Adigun, J. A., Hosu, D. O., Fanawopo, H. O. Daramola, O. S. and Osipitan, O. A.: Growth and Yield Performance of Two Lowland Rice Varieties (NERICA L-19 and WITA 4) as Influenced by Period of Weed Interference in the Forest-Savanna Agro-ecological Zone of Southwest Nigeria