Alleles are different forms of the same gene that control a specific trait in plants.
Here’s a simple explanation:
1. What alleles are:
Each gene exists in two or more versions called alleles. These alleles are located at the same position (locus) on a pair of homologous chromosomes.
- Example: A gene that controls flower color might have one allele for red flowers (R) and another for white flowers (r).
2. Inheritance of alleles:
Plants inherit two alleles for each gene — one from the male parent (pollen) and one from the female parent (ovule).
3. Function of alleles:
- Alleles determine how a particular trait appears in the plant.
- The combination of alleles (called the genotype) decides the visible characteristic (called the phenotype).
4. Types of alleles:
- Dominant allele: Expresses its trait even if only one copy is present (e.g., R → red flowers).
- Recessive allele: Expresses its trait only if two copies are present (e.g., r → white flowers).
5. Example:
If a plant has:
- RR → red flowers (homozygous dominant)
- Rr → red flowers (heterozygous)
- rr → white flowers (homozygous recessive)
6. Importance in plants:
Alleles create variation in traits such as flower color, height, seed shape, and disease resistance. This variation is important for plant breeding and evolution.
In short:
Alleles are alternative forms of a gene that determine how traits appear in plants. The combination of alleles a plant inherits from its parents controls its physical characteristics.