Principles of Genetics and Breeding

5.1.1.4 Heterosis

It was observed that, when two pure strains or races (differing from each other in a number of genes) are crossed, the resultant hybrids may be markedly superior to either parent with regard to size, vigour, vitality, resistance to unfavourable environmental conditions and diseases, etc .

• This superiority of the hybrid was termed heterosis by George Harrison Shull in 1914.
• He along with Edward Murray East, conducted elaborate studies of hybrid corn from 1905 to1930 and developed the genetic basis of heterosis concept.