Question

Which of the following does not apply to High Yielding Varieties (HYVs) of crops?

• A. They are semi-dwarf and are protected from strong winds.
• B. They mature early and save time for raising other crops in same field.
• C. They are disease resistant and does not require pesticides.
• D. They require better input like water and fertilisers.

Hint:

Green Revolution HYV Package:
1. Semi-dwarf non-lodging stalks.
2. High responsiveness to chemical fertilizers.
3. High demand for controlled irrigation.
4. High susceptibility to pests, necessitating regular pesticide use.

Answer 1

The Correct Option is C

Concept:
The Green Revolution introduced High Yielding Varieties (HYVs) of semi-dwarf wheat and rice developed through selective breeding by Norman Borlaug at CIMMYT and breeders at the International Rice Research Institute (IRRI).
These varieties responded well to chemical fertilizers, significantly boosting crop yields per hectare.

Step 1: Agronomic Characteristics of HYV Crops:
1. Semi-Dwarf Architecture (A): Incorporating dwarf genes (such as Norin-10 in wheat and Dee-geo-woo-gen in rice) produced short, thick stalks that prevented lodging (bending or breaking under heavy grain weight or strong winds).
2. Short Duration and Early Maturity (B): HYVs have shorter vegetative periods and mature quickly, allowing farmers to cultivate two or three crops annually on the same plot.
3. High Input Responsiveness (D): HYVs require managed irrigation and heavy applications of synthetic inorganic fertilizers (nitrogen, phosphorus, potassium) to achieve their yield potential.

Step 2: Analysis of Disease and Pest Resistance:
- Pesticide Requirement (C): It is incorrect to claim that HYVs "do not require pesticides."
- Because HYVs were bred from a narrow genetic base and planted in dense monocultures, they were often highly susceptible to pest infestations and fungal diseases (such as stem borer, brown planthopper, and rusts).
- As a result, HYV cultivation required extensive application of chemical insecticides, fungicides, and herbicides.
Final Answer:
The claim that HYVs are disease-resistant and do not require pesticides is incorrect, corresponding to option (C).