Genotype by environment interaction for egg number and egg weight of five dual-purpose chicken breeds in different zones of Oromia region in Ethiopia

The African Chicken Genetic Gain (ACGG) project (https://africacgg.net/) aims at backyard poultry optimization by commercial dual-purpose breeds introduction into Africa. To measure benefits, genotype by environment interaction (GxE) analysis provides guidance while predicting environmental effects on production traits of breeds. A survey among Ethiopian poultry smallholders showed egg sale being the most important purpose of keeping village chickens in Oromia. Data was available about laying of 894 ACGG chickens in Oromia. Hence current research questions were: 1) Does GxE take place? 2) Which breed performs best regarding laying and in which environment within Oromia? Traits investigated were egg number and egg weight of five breeds (S-RIR, Sasso, Horro, Kuroiler and Koekoek) located in three zones (East Hararge, East and West Shoa) and 5 districts (Adami Tulu, Bako Tibe, Dano, Dugda and Haromaya) in Oromia. Observations were taken as group measure performing weighted analyses. GxE was only present for egg number with magnitude strongest for zone. S-RIR performed best for both traits in both environments, except Kuroiler performing better in East Shoa for egg number and Koekoek for egg weight. This indicates success of crossbreed S-RIR. Sasso and Horro performed worst supported by previous research for Horro but not Sasso. Low precipitation in East Shoa caused bigger distance in egg number predictions, being higher for S-RIR and lower for Horro and Sasso compared to West Shoa. Apart from these final conclusions, social context of breeding and data collection difficulties should not be forgotten. Just like relevance of other performance trait analyses.