An Overview on the Concept and Utilization of Heterosis in Livestock

Aayush Yadav; Asit  Jain; Jyotimala  Sahu; Ashutosh Dubey; Rajkumar Gadpayle; Deepti Kiran Barwa; Sandhya Kasyap; Anuj  Singh

Authors

Aayush Yadav Department of Livestock Production and Management, College of Veterinary Science and Animal Husbandry, CGKV, Anjora, Durg-491001, Chhattisgarh, INDIA
Asit Jain Department of Animal Breeding and Genetics, College of Veterinary Science and Animal Husbandry, CGKV, Anjora, Durg-491001, Chhattisgarh, INDIA
Jyotimala Sahu Department of Livestock Production and Management, ICAR-National Dairy Research Institute, Karnal-132001, Haryana, INDIA
Ashutosh Dubey Department of Livestock Production and Management, College of Veterinary Science and Animal Husbandry, CGKV, Anjora, Durg-491001, Chhattisgarh, INDIA
Rajkumar Gadpayle Department of Livestock Production and Management, College of Veterinary Science and Animal Husbandry, CGKV, Anjora, Durg-491001, Chhattisgarh, INDIA
Deepti Kiran Barwa Department of Animal Breeding and Genetics, College of Veterinary Science and Animal Husbandry, CGKV, Anjora, Durg-491001, Chhattisgarh, INDIA
Sandhya Kasyap Department of Livestock Production and Management, College of Veterinary Science and Animal Husbandry, CGKV, Anjora, Durg-491001, Chhattisgarh, INDIA
Anuj Singh Department of Animal Nutrition, College of Veterinary Science and Animal Husbandry, LUVAS, Hisar-125001, Haryana, INDIA

Keywords:

Crossbreeding, Heritability, Heterosis, Hybrid Vigour, Non-additive Gene Action

Abstract

Heterosis or hybrid vigour is the excellence of F₁ cross beyond the average performance of the two parents and noticeable across species. Heterosis, coined by Professor G.H. Shull in 1914 is well known to exploit the benefits of crossbreeding. Heterosis is usually positive but negative heterosis does occur and is uncommon. Heterosis is widely accepted to occur due to non-additive gene action i.e. dominance, over-dominance and epistasis. The heterotic effects are usually expressed in percentage and always highest in F₁ generation followed by a decline in later generations. This decline is mainly due to the recombination and segregation losses. Rotational crossbreeding systems are therefore followed to maintain levels of heterosis in later generations. Estimates of heterosis are high in low heritable traits followed by moderate in moderately heritable traits and negligible in high heritable traits. Besides improvement, there are some limitations to heterosis that shall overcome shortly.