**Acknowledgements**

This study was carried out with the support by the Department of Biodiversity, University of Limpopo. The author acknowledges Dr. P.W. Mokwala and Mr. F. Nndwambi for providing seeds of soybean. Many thanks to Mr. L. Ramoba, F. Nukeri, S. Thosago, F.M. Masiya, R. Mudau, V.L. Makwana, L.R. Mahuluhulu, L.M. Marotola, K.K. Boshomane, M. Lutombo and T. Maleka for their technical support.
