Selection of parents for the generation of heterosis
Heterosis refers to the superior phenotypes observed in hybrids relative to their inbred parents with respect to traits such as growth rate, reproductive success, and yield. Heterosis was discovered in maize about a century ago and has subsequently been found to occur in many crop species. The increase in yield as a result of the cultivation of hybrid offspring ranges from 15 to 50%, depending on the crop (Lippman and Zamir, 2007).