High yield crops can be any cash crop (wheat, cotton, etc.) that produces an unnaturally large harvest. Typically, high yield strains are more resistant to disease and inclement weather although they sometimes require artificial fertilizers or pesticides for best results.
Environmentalists argue that genetically modified strains are not only unethical but also unhealthy, while commercial farmers and others maintain that high yield crops are necessary in order to feed the world's growing population and to stem global food shortages.