**Author details**

Godfrey Omulo Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Universität Hohenheim (490), Stuttgart, Germany

\*Address all correspondence to: omuloh@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
