Its all about the money; getting funds to conduct the research that you want to carry out. It is quite a rigorous and competitive process for funders to commit to your project.
As a scientist in Africa, getting access to some of the reagents takes much longer than our western counterparts and that affects the turnaround time for your research. An example most things are shipped from Europe or America and can take a month to get here whereas it takes days to get to the scientists in the developed world. If you find out that there is something wrong with your reagent or you want to try something different based on the results of your previous experiments it takes much longer to change direction.
Lack of investment or buy in from African governments such that they don’t allocate sufficient funds is a serious challenge for the growth of science and research that can solve our problems.