Radiation plays a major role in inducing mutations in plants by causing changes in the DNA of cells. This process is known as radiation mutagenesis. It is widely used in plant breeding to create new genetic variations and develop improved crop varieties.
How radiation induces mutations
Radiation affects the DNA in plant cells in several ways:
- It can break DNA strands, leading to rearrangements or deletions of genetic material.
- It can alter the chemical structure of DNA bases, causing incorrect base pairing during replication.
- It can create free radicals inside the cell, which damage DNA molecules.
These effects can result in gene mutations (changes within a gene) or chromosomal mutations (changes in chromosome structure or number).
Types of radiation used
- Ionizing radiation – includes X-rays, gamma rays, and fast neutrons. These have high energy and can deeply penetrate tissues, causing major changes in DNA.
- Non-ionizing radiation – includes ultraviolet (UV) light, which causes smaller changes such as base pairing errors, especially thymine dimers (bonding between two thymine bases).
Applications in plant breeding
Radiation is used to:
- Develop new plant varieties with improved traits such as disease resistance, drought tolerance, or higher yield.
- Create flower color and fruit shape variations in ornamental plants.
- Generate genetic diversity for research and selection programs.
Examples
- Gamma rays have been used to produce improved rice, wheat, and barley varieties.
- UV radiation has been used to induce pigment changes in flowers and fruits.
Precautions
Radiation must be applied carefully, as excessive doses can kill cells or cause harmful mutations. Proper dosage and exposure time are essential for useful mutation induction.
Summary
Radiation induces mutations by damaging or altering the DNA in plant cells. When used in controlled amounts, it helps plant breeders create new, beneficial traits and increase genetic diversity for crop improvement.