It's a poisonous loop. Initially the yields will be high with seeds of Monsanto because what ever modification done will be effective. This results in depression of prices and farmers have to compete on volume to make decent profits. Since normal seeds can't do that, all farmers are forced to use GM seeds. Once majority of farmers shift to GM seeds, farmers go back to earning the same profit while paying extra for monsanto. And more importantly, if they lose the crop for any reason (very common in India due to droughts/floods), they will go underwater and might even lose their land on which they take loans every year. This leads to suicides. This is exactly what happened with BT cotton which is one of the reasons why Indian govt blocked BT brinjal.