Crop Variety Improvement – Long Answer Questions
Medium Level (Application & Explanation)
Q1. Explain what hybridization is and describe its three types with suitable examples of when each is used.
Answer:
- Hybridization means crossing genetically different plants to get a better variety.
- Intervarietal is crossing two varieties of the same species. Use it to improve yield or quality in the same crop.
- Interspecific is crossing two species of the same genus. Use it to bring in disease resistance from a related species.
- Intergeneric is crossing plants from different genera. It is rare. It is tried for special traits.
- This method aims for higher yield, better quality, and resistance.
- The final goal is a crop that fits farm needs and local conditions.
Q2. Why must new crop varieties show good performance in different areas and have high-quality seeds?
Answer:
- Farmers in different places face different soils and weather.
- A good variety must show stable, high yield in many areas.
- Seeds must have high quality and good germination for better plant stands.
- Good seeds give uniform growth and healthy plants.
- This reduces risk and increases profit for farmers.
- It also builds trust in the new variety and helps adoption.
Q3. Explain how weather, soil quality, and water availability affect crop yield. Link this to why crop variety improvement is needed.
Answer:
- Weather like droughts or floods can damage crops and reduce yield.
- Soil quality decides how well roots grow and how nutrients are taken up.
- Water availability controls germination, growth, and flowering.
- Poor weather, soil, or water leads to low yield and crop failure.
- So breeders work for abiotic resistance like drought or flood tolerance.
- They also build wider adaptability so crops perform well in many conditions.
Q4. What are desirable agronomic characteristics, and how do they help increase productivity?
Answer:
- Agronomic characteristics are plant features that help in farming.
- Tallness is useful in fodder crops to give more biomass.
- Dwarfness in cereals prevents lodging and supports higher yield.
- Good branching or tillering raises the number of grains or pods.
- Plants with strong stems and compact canopy are easy to manage.
- These traits make crops productive, stable, and farmer-friendly.
Q5. Explain how changing the maturity duration of crops benefits farmers.
Answer:
- Shorter maturity allows more crops per year on the same field.
- It lowers production costs like irrigation and labor.
- It helps crops escape stress like late-season drought or flood.
- Harvest becomes quicker and easier.
- It fits better in cropping calendars like rice–wheat–pulse rotations.
- Overall, it increases total annual yield and improves income.
High Complexity (Analysis & Scenario-Based)
Q6. A farmer in a drought-prone area with poor soil must choose between intervarietal hybridization and a GMO with a drought-tolerance gene. What should they consider and why?
Answer:
- First, check the severity of drought and soil fertility.
- Intervarietal hybrids may give higher yield and some stability, but drought tolerance may be limited.
- A GMO with a drought-tolerance gene can give better survival under low water.
- Also consider seed cost, availability, and local rules on GM crops.
- If drought is frequent and severe, the GMO may offer more reliable yield.
- If drought is mild and inputs are low, an intervarietal drought-tolerant line may be enough.
Q7. A seed company wants to release a new wheat variety across different climates. What tests and traits must they prioritize to ensure wider adaptability and acceptance?
Answer:
- Test the variety in multiple locations and seasons for stable yield.
- Check baking quality, grain size, and protein for quality.
- Ensure seed quality with high germination and vigour.
- Screen for biotic resistance to common wheat diseases.
- Screen for abiotic tolerance like heat, drought, or waterlogging.
- Confirm maturity duration fits many cropping systems without yield loss.
Q8. A breeder wants disease resistance in a crop. Compare intervarietal, interspecific, and intergeneric hybridization for this goal and suggest the best starting choice.
Answer:
- Intervarietal: Same species. Easier crosses. Good for yield + resistance if resistance exists in a variety.
- Interspecific: Different species in same genus. Can bring strong resistance from wild relatives. May face fertility issues.
- Intergeneric: Different genera. Very rare. Complex and often sterile. Used only for special traits.
- For disease resistance, start with intervarietal if resistance is present within the species.
- If not, try interspecific to bring resistance from a related species.
- Use intergeneric only as a last option due to low success.
Q9. A region faces pest outbreaks and also floods every alternate year. Design a crop improvement plan to tackle both biotic and abiotic stresses.
Answer:
- Choose or breed for biotic resistance to key pests and diseases.
- Add abiotic tolerance to flooding or waterlogging.
- Keep shorter maturity to avoid peak flood periods if possible.
- Prefer strong stems and compact plants for less damage.
- Test across years and locations to check stability.
- Provide high-quality seed with good germination for quick crop recovery.
Q10. Water is limited in a village, and irrigation is costly. How should farmers and breeders align maturity duration and plant architecture to improve yield?
Answer:
- Use early-maturing varieties to cut water use.
- Select crops with efficient roots and drought tolerance.
- Prefer dwarf cereals to reduce lodging and save inputs.
- Use good seed with high germination to avoid re-sowing.
- Plan rotations that fit rainfall and avoid peak dry spells.
- This alignment saves costs, ensures survival, and keeps yield stable.