1. N. M. Akpan:
Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria
2. P. E. Ogbonna:
Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria
3. V. N. Onyia:
Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria
4. E. C. Okechukwu:
Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria
5. I. A. Atugwu:
Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria