This is another application that has been used by mankind over millennia. The farmer examines a population of individuals that show variation for a specific trait. From these, those that meet particular criteria are selected and kept aside to grow a new population which is then maintained. Traditional varieties of crops and animal species have been developed based on this method. In plants, characteristics such as size, colour, taste etc. have been selected for giving us the range of varieties of crops such as Bambara groundnuts (tindlubu), cowpea (tinhlumaya), pumpkin etc. that we know.