Genetic gains in grain yield in spring wheat in Turkey

Abstract

Genetic gain for grain yield was evaluated in 35 Turkish spring wheat varieties released between 1964 and 2010. The germplasmcomprised varieties developed by the East Mediterranean Agricultural Research Institute (ARI) in Adana, the Maize Research Station inAdapazarı, and Aegean ARI in İzmir. Out of 34 varieties studied, 24 were selected from CIMMYT germplasm. The trials were conductedduring 2009–2013 at the same three sites. Average yearly genetic gain for all varieties was 30.9 kg/ha or 0.62%. The top five highestyielding varieties were all released after 1998: Ziyabey, Menemen, and Meta (İzmir), and Karatopak and Ceyhan (Adana). Plant heighthad a clear tendency to decrease over time. Genetic gain in yield was associated with genetic gains in harvest index (0.51%), the numberof spikes/m2 (0.29%), and the number of grains/spike (0.26%). Kernel size and biomass did not change over time and represent traitsto be explored in the future. The newest varieties combined higher yield with yield stability. Resistance to leaf rust contributed greatlyto yield genetic gain. Turkish breeders made a substantial impact on national grain supply and food security. Future breeding strategiesshall combine the utilization of CIMMYT germplasm, a diverse modern gene pool, and genetic resources in an integrated nationalbreeding program.