Selection for Economic Traits in Chickens Breeding Program According to Genetic Parameters and Correlation Between Traits

Identification of genes determining the expression of economically important traits of plants and animals is a main research focus in agricultural genomics. Most of these traits are characterized by a wide variability of the expression of genes at certain loci called quantitative trait loci (QTL). Characterization of the chromosomal regions carrying QTL can be applied in marker-assisted Selection (MAS) to improve breeding efficiency. Molecular linkage maps in combination with Powerful statistical methods facilitate the genetic dissection of complex traits and the chicken is Ideally suited for this task due to a relatively short life cycle and large number of progeny. Native chickens are important in some rural areas. They usually produce meat and eggs without extra feed, only picking food. Improving their economical traits, such production efficiency would save these genetic resources. The genetic parameters for various traits of economic importance were studied in an Iranian Native chickens population under short term selection for egg production and body weight for over 2 years. The parameters studied were body weight at day old (BW1), 8 weeks (BW8) and body weight at 12 weeks (BW12), the weight of first egg (EGGW1) and egg weight at 30weeks of age (EGGW30) also the average number of stock eggs per day(EGG/DAY). They showed mostly moderate to high heritability estimates. All these values were 0.56 to 0.44, 0.51 0.2, 0.56 and 0.15 respectively. Higher heritability estimate were obtained for body weight traits. There were positive genetic correlation between weight traits and egg weight traits. Higher estimate was obtained for BW1 and EGGW30(0.64). However, negative genetic correlation between body weight traits and number of eggs are estimated. In the result, selection for body weight traits before mature ages will cause gain in egg weight traits and it will be useful in breeding plans.