Clean seed stocks and roguing
The basis of seed production is the use of clean seed stocks and the removal of diseased plants from seed plots.
Clean seed stocks
When started with a clean seed stock, during the first generations the percentage of virus infested plants is relatively small, but in the following generations when the number of infection sources increases, the degeneration process accelerates.
A seed multiplication programme can be best started with an almost clean seed stock (Basic seed). Early roguing, to be continued until the end of the season, is applied to keep the number of infection sources low.
Start with clean seed stocks
Roguing
The most common reason for roguing is the presence of virus diseases. When roguing the green plant parts as well as the tubers are removed from the field. The roguing is done as soon as the virus diseased plants are visible.
The reason for this is:
- to remove the infection sources before other plants become infected
- that the young plants are still small and relatively easier to remove than full grown plants
If at the time of roguing aphids are present, it is recommended to kill these aphids before starting to rogue. The aphids on virus infected plants will in many cases be infected with virus and with roguing these plants the virus infected aphids will spread to the healthy plants.
For practical reasons it is often recommended not to apply roguing in crops when the percentage of virus infected plants exceeds 2%.
ROGUING