Genetic Basis in Self-Pollinated Crops
Self-pollinated crops are characterized by their natural tendency to undergo autogamy (self-pollination), which has significant implications for their genetic structure and breeding strategies.
Key Genetic Features of Self-Pollinated Crops
High Homozygosity:
- Repeated self-pollination leads to an increase in homozygosity, where most loci in the genome become fixed (homozygous).
- Heterozygosity decreases by half with each generation of self-pollination.
Pure Line Formation:
- Populations of self-pollinated crops consist predominantly of pure lines.
- A pure line is a homozygous individual derived by selfing and selection over successive generations.
- Example: Mendel’s pea plant experiments demonstrated the development of pure lines.
Limited Genetic Variation:
- Due to high homozygosity, genetic variation within populations of self-pollinated crops is minimal.
- Most variation arises from natural mutations or deliberate hybridization.
Genotypic Stability:
- Homozygous individuals exhibit stable genotypes, which remain consistent across generations unless a mutation or cross occurs.
- This stability makes self-pollinated crops reliable for cultivation.
Expression of Recessive Traits: Self-pollination exposes and fixes recessive traits, which may remain hidden in cross-pollinated populations due to heterozygosity.
Inheritance Patterns: Traits in self-pollinated crops generally follow Mendelian inheritance, with clear segregation patterns in early generations after hybridization.
Examples of Self-Pollinated Crops
- Cereals: Wheat, rice, barley, oats.
- Legumes: Pea, chickpea, soybean, pigeon pea.
- Oilseeds: Groundnut, sesame.
