Effects of Cytoplasm Inheritance on Production Traits of Merino Sheep

To evaluate the effects of cytoplasm lineage (CL) the body weight (BW, n = 707) and greasy fleece weight (FW, n = 703) of females and fiber wool diameter (FD, n = 350 males) of males sheep from yearling Merino sheep were used. The p edigree information included 3,645 animals and an average of 10 generations. The Maximum Restricted Likelihood methodology and animal m odels that included the direct genetic, direct and CL effects, direct, maternal and CL effects and direct, maternal, environmental ma ternal effects were used. Fixed effects of year and season of birth were included in all models. The likelihood ratio test was used for compar isons between the models. There were no differences b tween models including or not CL, indicating that CL effects w ere not important for the studied traits. For BW, the results indicated a partial confounding among the maternal additive genetic, environmental maternal and CL effects. The importance of maternal additive effects was greater for the BW traits (from 24.5% at least to 7.9% in the most comprehensive mo d ls) than for FW and FD. The relative importance of direct additive effects was also greater for BW (from 24.5 to 37,1%, for the differen t models), followed by FW (from 19.5 to 24.6%) and for FD (from16.3 to 21.0%). The heritability estimates indicated that the successful s el ction could be obtained for body weight, fleece weight ad fiber wool diameter of sheep Merino breed.