Genetic Gains in Grain Yield and Agronomic Traits of Argentinian Durum Wheat from 1934 to 2015

Abstract

Understanding the basis of genetic gains in grain yield and yield-related traits is essential for designing future breeding strategies that lead to the development of higher-yielding wheat cultivars. The objectives of this study were to assess the changes in grain yield achieved by durum wheat breeding in Argentina and to identify the agronomic traits associated with these changes. To this end, a wide set of Argentinian cultivars was analyzed in three field trials. A significant linear trend (R2 = 0.55) was observed between the grain yield and the cultivar’s release year, with an increase of 26.94 kg ha−1 yr−1 from 1934 to 2015. The harvest index and grain number were key traits that explained the increases in grain yield. The number of grains per plant increased with the cultivar’s release year, while the thousand kernel weight remained unchanged. The grain yield showed an increase of 51% when comparing old cultivars (<1980) with intermediate ones (1980–1999), whereas the increase between intermediate and modern cultivars (2000+) was only 16%. Thus, the genetic gains were mostly associated with the incorporation of semi-dwarfism into the germplasm in the 1980s, with low genetic gains after that.