Genomic Selection For Pre-Harvest Sprouting Tolerance In Winter Wheat.

Pre-harvest sprouting (PHS) is a major problem in wheat that occurs when grains in a mature spike germinate before harvest, resulting in reduced quality and grain sale price.  Improving PHS tolerance (PHST) is a challenge to breeders because it is quantitatively inherited and tedious to score.  Genomic selection (GS) has shown promise for genetic improvement in breeding programs and is particularly useful for predicting phenotypes that are costly and time-consuming to assess.  In this study we used genome-wide markers to develop predictive models for PHST.  A training population of 399 lines representative of Colorado State’s wheat breeding program was scored for PHST over multiple years and genotyped using genotyping-by-sequencing (GBS) methodology.  Various cross-validation methods were used and models selected based on accuracies.  Preliminary, advanced, and elite nursery trials from the 2012 – 2013 growing season were genotyped and scored for PHST.  Selected models were applied to these lines and predictions compared to observed phenotypes.  GS models with high accuracies for PHST may be useful in a breeding program focused on implementation of GS to increase genetic gain for grain yield and other traits.