(a) Distinguish between a field pest and a storage pest. [2 marks]
(b) Give two reasons for early harvesting of maize from the field. [2 marks]
(c) Describe each of the following methods of crop improvement:
(i) introduction;
(ii) cross breeding. [6 marks]
(d) List six factors that should be considered in selecting a crop variety for your locality. [6 marks]
Explanation
(a) Distinction between field pest and storage pest:
A field pest is any organism which causes damage to crops when still on the field before harvesting whereas, a storage pest is any organism which causes damage to farm produce in storage.
(b) Reasons for early harvesting of maize from the field:
-To minimize/prevent/control pest attack
-To minimize/prevent/control disease outbreak
-To obtain fresh cobs for human consumption
-To avoid bad weather
(c) Description of methods of crop improvement:
(i) lintroduction
- Involves taking a crop from areas where it has been existing to areas where it has not been existing
- 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 t have passed quarantine tests
(ii) 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
(d) Factors that should be considered when selecting a crop variety for a locality
- Resistance to diseases
- Tolerance to pests
- Adaptability to climatic conditions
- Adaptability to soil requirements
- Superior yield
- Superior quality
- Early maturity
-Uniform growth habit
-Cost of production/other factors of production
-Taste of consumers
-Cultural taboos
-Availability of planting materials
-Availability of land
-Ability to smother weeds