CCA Crop Growth and Development 3 — Questions and Answers
Question 1: Vernalization is the process by which flowering is promoted by:
- Extended exposure to high temperatures
- Extended exposure to low temperatures (Correct answer)
- Increased day length
- High soil nitrogen levels
Correct answer: Extended exposure to low temperatures
Vernalization requires a prolonged period of cold temperatures to satisfy the plant's requirement before it can flower.
Question 2: The R1 growth stage in soybeans is characterized by:
- First trifoliate leaf unrolled
- Beginning of pod fill
- Beginning bloom (one open flower at any node) (Correct answer)
- Full seed (pods at upper four nodes filled)
Correct answer: Beginning bloom (one open flower at any node)
R1 in soybeans marks the beginning bloom stage when one open flower is visible at any node on the main stem.
Question 3: What is the primary role of the endosperm in a seed?
- Protects the embryo from desiccation
- Provides nutrients to support embryo germination and early seedling growth (Correct answer)
- Houses the root meristem
- Regulates water uptake during imbibition
Correct answer: Provides nutrients to support embryo germination and early seedling growth
The endosperm is a nutrient storage tissue that supplies energy and nutrients to the embryo during germination.
Question 4: Apical dominance in plants is maintained primarily by which hormone?
- Abscisic acid
- Ethylene
- Auxin (IAA) (Correct answer)
- Cytokinin
Correct answer: Auxin (IAA)
Auxin produced by the apical bud suppresses lateral bud growth, a phenomenon known as apical dominance.
Question 5: Which of the following crops is classified as a C4 plant with higher photosynthetic efficiency under hot, dry conditions?
- Wheat
- Soybean
- Corn (maize) (Correct answer)
- Alfalfa
Correct answer: Corn (maize)
Corn is a C4 plant that uses a more efficient carbon fixation pathway, giving it a competitive advantage in hot, sunny, and water-limited environments.
Question 6: Leaf area index (LAI) is defined as:
- The ratio of leaf length to leaf width
- Total one-sided leaf area per unit ground area (Correct answer)
- The number of leaves per plant
- The rate of leaf appearance per degree-day
Correct answer: Total one-sided leaf area per unit ground area
LAI is the total one-sided area of leaf tissue per unit surface area of land, used to quantify canopy density.
Question 7: During seed germination, the radical is the first structure to emerge and develops into the:
- First leaf
- Primary root (Correct answer)
- Seed coat
- Hypocotyl
Correct answer: Primary root
The radicle is the embryonic root that emerges first during germination and develops into the plant's primary root system.
CCA Crop Growth and Development 3
Vernalization is the process by which flowering is promoted by: