This question was well attempted by the candidates. In 6(a), majority of the candidates could distinguish
between a field pest and a storage pest. Also, in 6(b), many candidates were able to give reasons for the
early harvesting of maize from the field.
However, in 4( c), many candidates could not describe methods of crop improvement such as introduction
and cross breeding In 6(d), majority of the candidates were able to list factors that should be considered
in selecting a crop variety for a locality.
The expected answers include:
Description of methods crop   improvement
Introduction
Involves taking a crop from areas where it has existed to areas where it has not been existed.
This is possible if the environmental conditions in such areas are similar to those of the plant's
original home;
Pollen can be collected and shipped to other areas for artificial pollination;
Plants are allowed into most countries only after they have passed quarantine tests.
Cross breeding
Involves the transfer of heritable traits from one plant to another of the same species but different
varieties through the fusion of their male and female gametes;
It is used to upgrade species of plants which have qualities such as high yield, disease-resistance
and heat/drought/wind tolerance;
 

Pollen grains from plants with desirable qualities can be collected and transferred manually to
the stigma of the flower of another plant of the same species which might be lacking in such
character, but has its own special trait such as adaptation to a particular environment;
Offspring with the desirable qualities is selected for propagation.