Principles of Genetics and Breeding

11.1.9 Heterosis or hybrid vi

11.1.9 Heterosis or hybrid vigour

It is a phenomenon observed in cross bred population.

• When the lines or sub-populations are crossed, the mean of the crossed progeny for one or more character becomes more than the average of the parental lines in most of the cases. This is known as ‘heterosis’ or ‘hybrid vigour’.
• Heterosis is due to non- additive gene action in the character.
• It is the opposite of the inbreeding depression that is observed due to inbreeding in the lines.
• Crossing in commercial populations is done to utilize the heterosis in a character.