Actually, I'm not sure that it isn't in a farmers own interest to invest in genetically diverse seeds. A farmers lively hood depends on the success of his crops

Actually, I'm not sure that it isn't in a farmers own interest to invest in genetically diverse seeds. A farmers lively hood depends on the success of his crops, so diversifying them would make him more resistant to unexpected crop failures. In this way, we could view diverse seeds as a type of insurance. However if a farmer takes this insurance, even if it is a net positive investment in the long term, he will not be able to sustain himself in the short term. You typically need large entities (be them public or private) to make this type of long term investment. If it is not innitiated by the government, we might see Monsanto (or other large GM companies) make the investment. Because if one of Monsanto's crops fails catastrophically, they loose alot, however they have the capital to invest in making their crop resistent to mass failure by introducing genetic diversity. Unfourtuantly companies also tend to focus short term. If we're lucky, we will see localized mono-culture failures which will incentives all involved to invest in geneticly diverse crops.