**2.4 Postgraduate studies on local chicken improvement at Federal University of Agriculture Abeokuta from 1980 to 2005**

**Heritability and genetic correlations:** The genetic studies conducted at the Federal university of agriculture Abeokuta and University of Ibadan by Ige [41], Adeleke et al., Ogunsola [42], and Ajayi [43] showed that heritability estimates for body weight, body length, and breast girth were 0.30–0.62, 0.97, and 0.97, respectively. Heritability estimates for semen volume and motility ranged from 0.01 to 0.46.

The phenotypic correlation coefficients between body weight and other ranged from 0.13 to 0.92. Genetic correlation coefficient was high and positive and ranged from 0.40 to 0.99 and 0.43–0.99 between body weight and other traits [41, 42]. Highly significant correlation coefficients indicated that meaningful improvements can be made through selection of pair of traits that were positive and significant.

**Crossbreeding:** Several studies at the University of Nigeria Nsukka, University of Agriculture Abeokuta, and NAPPRI Zaria evaluated the performance of cross-bred chickens. The results of those studies revealed that the exotic and their crosses had better performance in body weight and semen volume than the local chickens (Adebambo et al. [44]; Akpan [40]; Akanni [45]; Adeleke et al. [46]; Adeleke et al. [47, 48], Adeleke et al. [49] and Sandaa et al. [50]).

The frizzling and naked neck genes conferred better feed conversion, growth rate, feed efficiency, and dressing percentage than the normal feathered chicken [43].

**Cross-breeding/combining ability:** Adebambo et al. [44] reported that Anak Titan had the best general combining ability (GCA) and some traits were found to be the most discriminating variables to separate the chicken genotypes [51].

**Molecular technique:** Little has been done on the molecular characterization of the indigenous chicken in Nigeria. It is, however, interesting to note that the two pioneer studies on molecular characterization of the indigenous chicken in Nigeria and DNA loop analysis at Abeokuta Adebambo et al. [52], Adebambo [52], and Ohwojakpor et al. [53] found no significant differences in genetic distance of indigenous chicken from three populations (Southwest, Northwest, and Northeast ecological zones) of Nigeria.

### **2.5 Genetic studies at National Animal Production Research Institute 2005**

The program for breeding in Nigeria started in 1985 at the National Animal Production Research Institute, Zaria [54]. Some studies at Zaria have evaluated the performance of "Shika breed" under different nutritional regime [55–57]. Apno et al. [58] reported continuous differences in almost all the measurable parameters of Adamawa State chickens.
