They are genetically capable of producing a higher grain output per plant.
Explanation
High Yielding Variety (HYV) seeds are genetically improved seeds developed to maximize agricultural output. Introduced during the Green Revolution, these seeds are designed to produce a higher ratio of grain to vegetative mass (harvest index) compared to traditional varieties, provided specific input conditions are met.
Option-wise Analysis
- They give high yields even when grown only with organic manure. is incorrect: HYV seeds are highly responsive to chemical fertilizers. They require heavy doses of synthetic fertilizers (Nitrogen, Phosphorus, Potassium) to achieve high yields and do not perform optimally with organic manure alone.
- They are suitable for cultivation under low irrigation conditions. is incorrect: These seeds are water-intensive and necessitate assured and regulated irrigation. They are generally unsuitable for dryland farming or areas with low irrigation, as water stress drastically reduces their productivity.
- They are genetically capable of producing a higher grain output per plant. is correct: The defining characteristic of HYV seeds is their genetic modification to ensure a higher grain output per plant. Traits often include dwarfism (to prevent lodging under the weight of grains) and a shorter maturity period, allowing for multiple cropping.
- They significantly reduce dependence on chemical inputs such as pesticides. is incorrect: HYV crops are often more susceptible to pests and diseases than traditional, locally adapted varieties. Consequently, their cultivation typically increases dependence on chemical pesticides and insecticides to protect the crop.
Key Takeaway: HYV seeds are part of an input-intensive "package technology" that requires chemical fertilizers, assured irrigation, and pesticides to deliver higher productivity; they are not self-sufficient or low-input varieties.