Mapping Quantitative Trait Loci Influencing Grain Yield and Agronomic Traits in Hard Red Spring Wheat.

Development of high performing wheat cultivars, with high grain yield, improved agronomic traits and grain quality, is a major focus in many wheat breeding programs worldwide. The main objective of the study was to identify chromosome regions harboring genes that influence grain yield, agronomic, and end-use quality traits in hard red spring wheat breeding lines adapted to the upper Midwest region of the U.S. Plant height, heading date, grain yield, test weight, grain protein, kernel size distribution, and 1000-kernel weight were evaluated from a population of 140 recombinant inbred lines (RILs), two parental lines, and three check varieties grown at three Minnesota locations in 2005 and 2006. Parental lines (MN98550 and MN99394) were screened for polymorphism at the USDA-ARS Small Grain Genotyping Center, Fargo, ND using 877 DNA markers that covered the entire genome of wheat. Only 28% of microsatellite markers were polymorphic and amplified 279 loci. Genetic linkage maps showing QTL regions were constructed and analyzed using Mapmaker v. 3.0b and QTL Cartographer v. 2.5, respectively. The QTL analysis is in progress.