Final answer:
The primary concern with virus-resistant genetically engineered plants is the potential emergence of (b) more pathogenic virus strains. Genetically modified crops, including drought-resistant, pest-resistant, and herbicide-resistant varieties, aid in sustainable agriculture by reducing the need for chemical pesticides and increasing the viable growing regions. Examples include virus-resistant papaya plants developed in response to a ringspot virus outbreak.
Step-by-step explanation:
The major concern with the first generation of plants engineered to be resistant to viruses is that more pathogenic virus strains may arise. This concern is valid because when plants are modified to be resistant to specific viruses, there is pressure on the viral populations to evolve and overcome the plant's defense mechanisms, which may lead to the development of more virulent strains that can bypass the engineered resistance.
Another reason such cultivation is important is that it can lead to the development of drought-resistant crops, which can greatly increase the range where major food crops can be grown. Additionally, pest-resistant crops can reduce reliance on environmentally toxic chemical pesticides, and herbicide-resistant crops can survive chemicals that are used to destroy harmful plants.
For example, papaya, potatoes, and squash have been engineered to resist viral pathogens such as the cucumber mosaic virus. In the late 1990s, papaya ringspot virus (PRV) led to the development of virus-resistant papaya plants that incorporated PRV DNA, resulting in a significant recovery of the papaya industry in Hawaii.