In Fowler's ted talk on crop diversity he claims that crop diversity is necessary for success of all crops. As the earth gradually heats up, crops are struggling to adapt and with stand the blistering temperatures. Farmers tend to use the crop species that achieve the highest yield, but as the farmers tend towards a single species many other species die off, even though those species could possess a DNA strand that allows it to quickly adapt to higher temperatures. Scientists could then use that DNA strand to genetically modify other crops, enabling them to withstand high temperatures.
http://www.ted.com/talks/cary_fowler_one_seed_at_a_time_protecting_the_future_of_food?language=en
http://www.ted.com/talks/cary_fowler_one_seed_at_a_time_protecting_the_future_of_food?language=en