The Irish Potato Famine happened because their potatoes were descended from a single handful of potatoes. As a result, a fungus that affected one potato plant affected every other potato plant. About a million people died from that.
The corn blight in 1970 resulted in the loss of 1/3 of the US corn crop. If the weather hadn't broken, up to 85% of that year's crop could have died. 85% of the seed grown back then used Texas Male Sterile Cytoplasm as part of the hybridization process. In response, the US government created and continues massive subsidies for corn production. This is why high fructose corn syrup is cheaper than cane/beet sugar, and why HFCS is so widespread in US food production.
One book that covers the history of monoculture failures like this is Altered Harvest:
One book that covers how prevalent corn is in American food production is Omnivore's Dilemma.
The banana flavor used in candies tastes nothing like Cavendish bananas. That flavor was based on the Gros Michel variety that went economically extinct in the 1950s.
The overall organization is little forced at times, but the research for each section is really interesting.
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