Thorny, precisely that. The whole narrowing of genetic diversity is scary. If only a few varieties of, say, corn or rice are resistant to the next fungal infection, and we have let those varieties drop out of the gene pool because they are not the highest yielding or the most attractive, we are in trouble. Wasn't there a recent problem in America with a new strain of corn smut, with one of the old varieties turning out to be resistant?
And while I am all for science, I think more caution needs to be applied to the rush for profits, and more responsibility needs to be taken for unintended consequences. 'We didn't mean for that to happen' is not much consolation to the folk who have lost their livelihood, and often their farms.
Plant Breeders' Rights is also an issue here. For something that started out last century with the benign intention of protecting the French rose breeding industry, it has become a monster, with most of the profit going to lawyers and big corporations - funny how often that happens. It is getting harder for gardeners and small farmers to save their own seed, and many heritage varieties and cultivars are extinct or dying out. There are a few success stories, like the 'Painted Lady' bean and the 'Moon and Stars' watermelon, but those are unfortunately exceptions to the general trend.
Then there is the business of seed patenting. Fair enough if the company or individual has actually bred or otherwise created the seed in question, but far too often these proceedings are intended to take a food plant or medicinal plant out of the hands of traditional users, or out of the Commons of mankind. I've helped to do the background research for several of the court cases opposing the attempts of pharmaceutical companies to patent traditional-use plants, and its a helluva slog, trying to document centuries of traditional use among people who may not be literate or have written records, and only know that their tribe has grown or wild-harvested this plant 'forever'. Because the problem is that once such a patent is in place, often without the traditional users or growers even being aware that this has happened, they are supposed to pay money when the plant is grown or used. If you want a case in point, look up 'Hoodia gordonii', an African medicinal plant that had the misfortune to be noticed by the American fatness industry (I won't dignify it with the name of 'weight-loss industry').
This is probably far too much serious stuff to inflict on you all - sorry!