Genetic Yield Gains and Changes in Associated Traits of CIMMYT Spring Bread Wheat in a “Historic” Set Representing 30 Years of Breeding

Abstract

ABSTRACTThe genetic yield progress of 26 spring wheat (Triticum aestivum L.) advanced lines released by the International Maize and Wheat Improvement Centre (CIMMYT) in the period from 1977 to 2008 was evaluated in the selection environment in Mexico as well as at a set of target environments in Asia and Africa. In Mexico, grain yield progress was significantly linear and about 0.7% yr−1 and yield was associated with fewer days to heading, cooler canopy temperature at grain filling, and increased stay‐green and thousand kernel weight. These results suggested that changes in the former traits at least partially explain the yield progress. When genetic yield progress was measured in subsets of sites in Asia and Africa grouped into high, intermediate, and low yielding, the genetic yield progress was 0.9, 0.7, and 0.5% yr−1, respectively. We conclude that there is no evidence that genetic gains to increase yield have slowed down in wheat lines released by CIMMYT.