Some key points to remember

• In 1717, Thomas fair child produce 1^st artificial hybrid called Fairchild’s mule.
• Genetic erosion: Gradual loss of variability.
• Genetic vulnerability can be avoided by male sterility and semi dwarfness, etc.
• Selection is the main cause of genetic variability.
• Self-incompatibility (SI) can be of one locus or multilocus.
• SI are of multi allelic generally.
• Hybrid vigor is synonym to heterosis and heterosis is antonym to inbreeding depression.