Climatic Change and Agronomic Performance of Hard Red Spring Wheat from 1950 to 2007

Increasing temperatures are a threat to hard red spring wheat (Triticum aestivum L.) production in the northern Great Plains and may impact objectives for breeding programs. Weather data and agronomic performance of experimental lines and a check cultivar 'Thatcher' were compiled for six sites in Montana for 1950 to 2007. Mean annual temperature increased significantly at five sites. March temperature increased significantly at all sites, and planting date has become significantly earlier at a rate of 0.24 d yr(-1). Grain yield of Thatcher increased significantly at a rate of 23.5 kg ha(-1) yr(-1). July temperatures increased significantly at two sites. July temperatures showed a significant negative correlation with grain yield at three sites and with grain volume weight at three sites. Nursery means over years as adjusted for Thatcher was used as a measure of genetic change and showed significantly increased grain yield and significantly earlier heading date. Our results suggest that earlier planting due to warmer spring temperatures has helped to alleviate negative effects of high temperatures during grain filling periods. Genetic changes in breeding materials have also contributed to increased yield potential, partially due to earlier heading and avoidance of July heat. Projection of increasing temperatures suggests the need for management and breeding strategies to insure productivity of hard red spring wheat in the northern Great Plains.