Definition of yield? Bushels per acre, or kg per hectare. There's not much of an issue there. The same plant might yield very differently in different fields, just like it yields differently each year. If you are conducting trials, you have to plant a bunch of stuff together vs well known controls. Something that yields 140 bushels per acre on average might give you just 58 in the wrong year. Just look at what happened to most of the US fall crop in 2012.
Now, if you plant a variety of plant that does well in X conditions, and you actually plant it in Y conditions, then yeah, pick between changing the condition or using a different variety.
sounds great. you're assuming that most people are critical of these crops. have any means to research what was mentioned(ie. internet). and have the means to recover from these loans, but if they did why would they need the loans to buy these crops to begin with?
just to chime in here. for a majority of indian farmers - partly which triggered the mass suicide by pesticide - they turned out to be not at all as high yielding as was claimed.
now you could say, ahhh, but wait a second. they didn't use as much water and pesticide as they were supposed to, and you might be right. but then it depends on your definition of yield.
their own crops had a higher yield given the conditions of the soil, and water.