Hybridisation and selection
Plant breeding · Biology
Study notes
Mule (horse × donkey) — sterile but stronger than either parent; classic hybrid vigour. Hybrid maize (shuttle breeding, Borlaug) doubled yields — farmers buy fresh hybrid seed yearly because vigour fades. Pusa Ruby tomato — Indian hybrid combining yield and disease resistance. But hybrid sterility (mule) shows crossing has limits — selection then fixes the gains.