Explanation

Seeds from virus infected plants generally do contain the virus. Therefore, sexual progeny are usually virus free, except for new-infections. But this belief is not entirely correct. In case of sexually reproducing crop virus infections spread rapidly. This is because of vegetative propagules from virus infected plants contain virus particle, hence in vegetatively propagated plants the virus gets transmitted through propagule (rhizome/bulb/tuber/root). But the growing bud is not infected (i.e., shoot tips are virus free)