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 germplasm comprised varieties developed by the East Mediterranean Agricultural Research Institute (ARI) in Adana, the Maize Research Station in Adapazari, and Aegean ARI in Izmir. Out of 34 varieties studied, 24 were selected from CIMMYT germplasm. The trials were conducted during 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 highest yielding varieties were all released after 1998: Ziyabey, Menemen, and Meta (Izmir), and Karatopak and Ceyhan (Adana). Plant height had a clear tendency to decrease over time. Genetic gain in yield was associated with genetic gains in harvest index (0.51%), the number of spikes/m2 (0.29%), and the number of grains/spike (0.26%). Kernel size and biomass did not change over time and represent traits to be explored in the future. The newest varieties combined higher yield with yield stability. Resistance to leaf rust contributed greatly to yield genetic gain. Turkish breeders made a substantial impact on national grain supply and food security. Future breeding strategies shall combine the utilization of CIMMYT germplasm, a diverse modern gene pool, and genetic resources in an integrated national breeding program.