UPSC MainsAGRICULTURE-PAPER-II201215 Marks200 Words
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Q7.

What is detasselling? How it helps in hybrid breeding?

How to Approach

This question requires a clear understanding of hybrid breeding and the role of detasselling. The approach should be to first define detasselling and its purpose. Then, explain how it facilitates hybrid seed production, focusing on preventing self-pollination and ensuring controlled cross-pollination. Structure the answer around these key aspects, using simple language and relevant examples to illustrate the process. A concluding statement summarizing the importance of detasselling in hybrid breeding is essential.

Model Answer

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Introduction

Hybrid seeds are crucial for enhancing crop yields and improving agricultural productivity. The production of these hybrid seeds relies on a specific breeding technique, and a key step in this process is detasselling. Detasselling is a vital practice, particularly prevalent in maize (corn) cultivation, and its importance is steadily growing with the increasing demand for high-yielding hybrid varieties. The process is intricately linked to the principles of plant breeding and controlled pollination, contributing significantly to global food security.

What is Detasselling?

Detasselling, derived from the words "de" (removal) and "tassel" (the male flower of maize), is the process of removing the tassels (male flowers) from a maize plant. The tassels contain the pollen, which is essential for pollination. This is typically done manually, although mechanical detasselling is also being explored. The purpose is to prevent self-pollination and ensure controlled cross-pollination.

How Detasselling Aids Hybrid Breeding

Hybrid breeding, also known as hybrid vigor or heterosis, combines the desirable traits of two different parent lines to create a superior offspring. Detasselling plays a critical role in achieving this.

The Process Explained

  1. Female Parent (Detasseled): The plants intended to be the female parent are detasseled early in their growth stage. This prevents them from releasing pollen and self-pollinating.
  2. Male Parent (Pollen Source): The male parent plants retain their tassels, acting as a pollen source.
  3. Controlled Pollination: When the female parent's silks (female flower parts) are receptive, pollen from the male parent is deliberately transferred to them, typically by wind or manual shaking.
  4. Hybrid Seed Production: The resulting kernels on the detasseled female plant are hybrid seeds, possessing the combined traits of both parent lines.

Importance in Hybrid Breeding

  • Prevention of Self-Pollination: Maize is naturally self-pollinating. Detasselling eliminates this possibility, ensuring that the female parent is pollinated only by the desired male parent.
  • Controlled Cross-Pollination: It allows breeders to control which plants are crossed, maximizing the chances of combining desired traits.
  • Hybrid Vigor (Heterosis): Hybrid seeds often exhibit superior traits like increased yield, disease resistance, and improved adaptability compared to their parent lines. This is the very essence of hybrid breeding.

Challenges and Future Trends

Detasselling is labor-intensive and can be costly. Research is ongoing to develop male-sterile maize varieties that eliminate the need for manual detasselling. Genetic engineering is also being explored to create self-incompatible maize lines, further streamlining the hybrid seed production process. The development of automated detasseling machines is also an area of active research.

Parent Type Role Tassel Status
Female Parent Receives pollen Detasseled
Male Parent Provides pollen Tassel intact

Conclusion

Detasselling is a cornerstone of hybrid maize breeding, ensuring controlled pollination and harnessing the benefits of hybrid vigor. While labor-intensive, its importance in enhancing crop yields and contributing to global food security remains undeniable. Future innovations, such as male-sterile varieties and automated detasseling, promise to further enhance the efficiency and sustainability of hybrid seed production, ensuring continued advancements in agricultural productivity.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Heterosis
Also known as hybrid vigor, it's the improved or increased function of any biological quality in a hybrid offspring.
Silks
The long, thread-like stigmas of a maize flower that receive pollen during pollination. They are the female reproductive parts.

Key Statistics

Hybrid maize varieties account for over 80% of maize production globally (FAO, 2021 – Knowledge Cutoff).

Source: FAO

Labor costs for detasselling can account for 20-30% of the total hybrid seed production cost in some regions. (Source: Agricultural Economics Journal, 2018 – Knowledge Cutoff)

Source: Agricultural Economics Journal

Examples

Monsanto (now Bayer) Hybrid Maize

Monsanto, now Bayer, pioneered the large-scale commercial production and distribution of hybrid maize seeds, significantly impacting global agriculture. Their varieties are known for high yields and disease resistance.

Frequently Asked Questions

Why is detasselling not practiced in all crops?

Detasselling is primarily used in crops like maize where self-pollination is the norm and controlled cross-pollination is essential for hybrid seed production. Other crops may have different pollination mechanisms or are propagated vegetatively.

Topics Covered

AgriculturePlant BreedingGeneticsHybrid SeedsPollinationCrop Improvement