Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: Selective breeding has resulted in plants that are resistant to pests and produce a higher yield of fruits and vegetables. Which of these is the most likely disadvantage that can result from this process?
decreased genetic diversity
Increased susceptibility to certain pests or diseases.