Effect of broodiness on production traits and its association with polymorphism in 5’ regulatory region of dopamine D2 receptor gene in Ghagus breed

Ghagus breed was characterized for broodiness, its effect on production traits and polymorphisms at 5’ regulatory region of dopamine D2 receptor (DRD2) and prolactin genes for their association with production and broody traits. A high incidence (85.4%) of broodiness was observed and it had a significant effect on production traits. The broody hens were (P<0.001) lesser in bodyweight than non-broody hens and the bodyweight decreased with the increasing duration of broodiness (DB). Non-broody hens produced more (P<0.001) eggs than the broody hens. The number of clutches and pauses was (P<0.001) higher in non-broody hens as compared to broody hens. However, the average pause size was significantly (P<0.001) lesser in non-broody hens. The number of clutches and pauses reduced while pause size increased significantly as DB increased. Insertion-deletion (InDel) genetic marker at 5’ region of the DRD2 gene was associated (P<0.05) with the age at first broody cycle, duration of the first broody cycle (P<0.01), egg production, and 40 weeks body weight (P<0.05) while SNP at 5’ region of DRD2 gene had significant (P<0.004) influence on 40 weeks body weight. The study concluded that broodiness had a significant influence on production traits and InDel and SNP markers at the 5’ regulatory region of DRD2 gene had significantly (P<0.004) affected the bodyweight at 40 weeks. The findings of the study could be useful for the development of breeding programs for the improvement of indigenous chickens like Ghagus.