Heterosis is the superior nature of the hybrids over their parents so it is also known as the hybrid vigour. The continuous inbreeding causes loss of heterosis. The heterosis can be maintained by the crossing of the plants with the inbreed lines. The heterosis nature has been exploited in various crop plants for the improvement of different plant varieties. By heterosis new varieties of field crops like Maize, Sugar beets, Sorghum, Grasses and Sunflower etc. are produced. Heterosis is used in horticultural crops like tomatoes, cucumber, Onion etc. and in flowering plants like the Marigold, Antirrhinum etc.
