A rogue plant is any plant that is a visibly different type from other plants of the same
crop growing together in the same field. They are not always a problem, but they are of
particular relevance to producers of seed crops, who try to produce a uniform and
standard product. This type of rogue, in a seed crop, is also known as an off-type, a term
which can apply to either the plant or seed. In this sense, to “rogue a field” means to
remove these off-type plants, normally by hand, before they flower and so leave a more
uniform quality of seed to be harvested.
For most farmers the word rogue means “weed”, such as wild oat rogues in a cereal
crop, which are also normally pulled up by hand since chemical control is unreliable or
very costly.
A volunteer is a plant of one species growing within a crop, or uncultivated land, of
another species. Volunteers usually come from the previous year’s crop, as a result of
seed or tubers being left behind in the field by mistake. Potato plants for example are
often found growing in the following year’s cereal or legume crop. Volunteers can also
be brought into the field with compost or manure, or by birds, animals or human feet.
Volunteer plants can be viewed from two points of view: either as a welcome extra
source of food in a mixed or hand harvested cropping system, or as a weed and a
nuisance in mechanised farming systems.
The benefits of crop rotations which are planned to control pests or diseases may
be reduced if volunteer plants appear in a crop because these pests and diseases may be
carried over in the volunteers and so survive and continue from one season to the next.
1F. THE SEED
Figure 7. Cross-section through a typical cereal seed (barley)