The correct answer is: d) All of the above
High-yielding varieties (HYVs) are crop plants that have been bred to produce more food per unit of land than traditional varieties. HYVs have been developed for a wide range of crops, including rice, wheat, and cotton.
The introduction of HYVs has had a major impact on agriculture around the world. HYVs have helped to increase food production and reduce hunger. They have also led to changes in agricultural practices, such as the use of more fertilizer and pesticides.
However, HYVs have also had some negative impacts. For example, they have led to the overuse of resources, such as water and land. They have also made farmers more dependent on external inputs, such as fertilizers and pesticides.
Overall, the introduction of HYVs has been a mixed blessing. They have helped to increase food production, but they have also had some negative impacts. It is important to weigh the benefits and costs of HYVs before deciding whether or not to use them.
Here is a brief explanation of each option:
- Rice: HYVs of rice were first developed in the 1960s. They have helped to increase rice production significantly. In fact, rice production has doubled since the 1960s, largely due to the introduction of HYVs.
- Wheat: HYVs of wheat were also first developed in the 1960s. They have helped to increase wheat production significantly. In fact, wheat production has tripled since the 1960s, largely due to the introduction of HYVs.
- Cotton: HYVs of cotton were first developed in the 1970s. They have helped to increase cotton production significantly. In fact, cotton production has doubled since the 1970s, largely due to the introduction of HYVs.