Genetic gains in wheat in Turkey: winter wheat for irrigated conditions
The study estimated genetic gain for yield and other traits in winter wheat released for irrigated environments in Turkey from 1963 to 2004. Yield trials including 14 varieties were grown in 16 environments from 2008 to 2012 in provinces of Konya, Eskişehir, Ankara, and Edirne. The highest yields were achieved by recent varieties Kinaci-97 (5.48 t ha− 1), Cetinel-2000 (5.39 t ha− 1), Alpu-2001 (5.44 t ha− 1), Ahmetaga (5.35 t ha− 1), and Ekiz-2004 (5.42 t ha− 1) compared to older varieties Yektay-406 (4.17 t ha− 1) and Bezostaya-1 (4.27 t ha− 1) released in the 1960s. The progress reached in grain yield in 20 years was 1.16 t ha− 1 or 58 kg ha− 1 (1.37%) per year. This gain was mainly achieved through shorter plant height and increased harvest index. There was no clear tendency of changes in specific yield components demonstrating that new high-yielding varieties may have different ways to reach their yield potentials. The yield gains were accompanied by improved stripe rust and leaf rust resistances primarily based on adult plant resistance genes. The grain quality of the new varieties did not deteriorate over time although most of them were inferior to the bread-making quality check Bezostaya-1, a feature that may require attention in future breeding.