Unit notes and practice questions
Everything here is for unit 3 of the Grade 12 Agriculture textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.
The cards filed under this chapter on the Grade 12 Agriculture page. Open one at a time.
| Origin Category | Crops Included |
|---|---|
| Indigenous to Ethiopia | Enset, anchote, Ethiopian potato, yam |
| Exotic (Introduced) | Taro, tannia, cassava, potato, sweet potato |
When you use it
Use when categorizing Ethiopian root and tuber crops by their geographical and evolutionary origin.
Watch out
Potato, sweet potato, and cassava are widely grown in Ethiopia but are exotic, not indigenous crops.
Drafted from Grade 12 Agriculture, pages 46-61, then checked twice before it went up
| Target Crop | Major Insect Pests | Major Diseases |
|---|---|---|
| Potato | Tuber moth, aphids, leaf miners | Late blight, bacterial wilt, virus |
| Sweet potato | Weevil, butterfly, hornworm | Viral diseases |
| Cassava | Green mite, red spider mite | Cassava mosaic virus |
When you use it
Use when identifying key biotic constraints that limit root and tuber crop productivity in Ethiopia.
Watch out
Late blight is the most destructive threat specifically for potato, while weevils specifically damage sweet potato.
Drafted from Grade 12 Agriculture, pages 46-61, then checked twice before it went up
When you use it
Use when explaining the physiological causes of post-harvest losses in root and tuber crops compared to cereals.
Watch out
Do not treat root crop storage like cereal grain storage. Cereal losses come mainly from external pests, whereas root and tuber losses stem primarily from high moisture content and internal physiological disorders like respiration, sprouting, and moisture loss.
Drafted from Grade 12 Agriculture, pages 46-61, then checked twice before it went up
10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.
Question 1
According to the textbook, what is a tuber crop?
Answer: A A crop with swollen underground stems and roots
Why
The textbook defines tuber crops as crops with swollen underground stems and roots, such as potatoes, sweet potatoes, and yams.
Question 2
Which of the following plants develops a thickened secondary root, known as a tuberous root?
Answer: A Sweet potato
Why
A tuberous root is a thickened secondary root, as seen in sweet potato and cassava. In contrast, carrot and sugar beet develop fleshy primary roots.
Question 3
Which of the following is classified as an indigenous root and tuber crop in Ethiopia?
Answer: A Anchote
Why
The major indigenous root and tuber crops found in Ethiopia are enset, anchote, Ethiopian potato, and yams. Taro, tania, and cassava are exotic species.
Question 4
What is the single most important factor affecting the rate of respiration in stored root and tuber crops?
Answer: A Temperature
Why
Temperature is the single most important factor affecting respiration rate, sprout growth, and the development of rotting micro-organisms during storage.
Question 5
Which root crop is considered an insurance crop and food security crop because it can be grown year-round under suitable climatic conditions?
Answer: A Sweet potato
Why
Sweet potato can be grown all year round under suitable conditions, making it an insurance crop and a vital food security crop in drought-prone areas.
Question 6
Which disease represents the most serious threat to increased potato production in Ethiopia?
Answer: A Late blight
Why
The textbook highlights late blight as the most serious disease threat to increasing potato production in Ethiopia.
Question 7
Approximately what percentage of Ethiopia is covered with natural water bodies (lakes and rivers) that facilitate root and tuber production via irrigation?
Answer: A 0.7%
Why
About 0.7% of Ethiopia is covered by natural water bodies, which enhances the potential for irrigated root and tuber crop production.
Question 8
What is a key botanical difference between rhizomes and roots?
Answer: A Rhizomes are horizontal underground stems that produce shoots and roots from nodes
Why
Rhizomes are stems that grow horizontally underground and send out new stems and roots from their nodes.
Question 9
Which insect pests are specifically identified as major threats to sweet potato production in Ethiopia?
Answer: A Weevil and butterfly
Why
The textbook specifically lists weevil and butterfly as major insect pests that hamper sweet potato productivity.
Question 10
Unlike cereal grains whose storage losses are mainly caused by external factors, root and tuber losses in storage are primarily caused by:
Answer: A Physiological disorders, moisture loss, and microbial spoilage
Why
Root and tuber crops have higher moisture content and metabolic activity, so storage losses are primarily driven by physiological disorders, water loss, and microbial spoilage.
The app holds 12 questions on this unit, marked as you go. These are the first 10.
Unit 3 runs from page 45 to page 59 of the Ministry of Education edition.
Ministry of Education edition, English, 302 pages
Temari turns this chapter into timed practice and marks it as you go, with an AI tutor to explain anything that did not land.
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