Virus Free Plants - Seeds from virus infected plants generally do not contain the virus. Therefore, sexual progeny are usually virus free, except for new infections. However, this belief is not entirely correct. Many viruses are now known to be seed transmissible.
This list is increasing as more and more viruses are closely and extensively investigated. But in case of asexually reproducing crops, virus infections spread rapidly. This is because the vegetative propagules from virus infected plants contain virus particles.