For example, in West Africa, there is plenty of water, but almost no irrigation and water control systems.

On the other hand, such technology would be valuable in Eastern and Southern Africa, where there is much less rainfall.  The problem is then delivery to the land.  In Israel, you don't have to go that far to deliver the water to the arable land, since it is such a small country.  And even that delivery is assisted by a much better developed infrastructure.  

Finally, much more needs to be done about post-harvest delivery.  The lack of infrastructure (especially road transport -  don't even talk about RRs,  they just don't exist) in much of sub-Suharan Africa limits the ability not only to deliver seed to the arable land, but getting the harvested product to market.

Now, I've just realized that I've been discussing all the problems in a diary which is supposed to be positive.  Not trying to hijack, just point out that a great deal still needs to be done.  The G8 need to look at the problems as a gestalt, and not try to solve them piecemeal.

But the journey of a thousand miles begins with the first step.