I apologize for not following the outlined framework on providing input as I want to make general comments.
1. Before talking about value chains, we need to make sure farmers can produce crops in the first place. In many regions of Africa, the land resource base has been degraded to a point where crop production is becoming impossible. So first we may want to think more about how to build soil health for sustainable crop production.
2. Most african small holder farmers grow food crops and in some cases in agroecological zones that are not favorable for those crops. Part of the value chain concept should be to encourage farmers to grow adaptable cash crops that they would inturn sell or trade for food. With some money in thier pockets farmers will be able to buy nutrition rich foods grown elsewhere
3. Not much is being said about indigenous fruits and food plants that are adapted to local conditions. In most cases these fruits and plants are nutrient dense and should be part of the VC equation. Programs should be put in place to harness these indigenous foods not only for home consumption but for sale to other parts of the world to generate income for local people. As it is, small scale holder farmers cannot compete with well subsidized farmers in developed countries with respect to major crops such as corn, rice, and wheat. Creating a niche market will make a big difference for Africa's small holder farmers
4. Health can be improved through producing safe food. So right from the begining, farmers should produce crops using fewer chemicals as possible. This would lead to nutrient dense and safe food.
Prof. Stephen Machado