Assessment of genomic prediction and genetic gain in multi-population half-sib families in the perennial grass crop intermediate wheatgrass

Authors: Bajgain, Prabin; JUNGERS, JACOB - University Of Minnesota; ANDERSON, JAMES - University Of Minnesota

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2026
Publication Date: 9/2/2026
Citation: Bajgain, P., Jungers, J.M., Anderson, J.A. 2026. Assessment of genomic prediction and genetic gain in multi-population half-sib families in the perennial grass crop intermediate wheatgrass. Genetics. https://doi.org/10.1371/journal.pone.0357452.
DOI: https://doi.org/10.1371/journal.pone.0357452

Interpretive Summary: Intermediate wheatgrass breeding programs in the USA mostly evaluate traits on several hundred individual plants. Yet farmers grow the crop in closely planted rows for large-scale grain production, creating a disconnect between research plots and commercial fields. In this study, we established row plots like a grower would and measured grain yield at multiple sites and years to identify plants with stable grain yield over three years. We also tested predictive accuracy of statistical models using data collected among the rows to learn if these models can be used to breed intermediate wheatgrass in row-planted selection nurseries. Our results showed moderate performance accuracies and we therefore recommend that breeding programs regularly evaluate row plots. This will help identify populations with improved performance while also benefiting growers by making research data more relatable to how they farm.

Technical Abstract: The University of Minnesota has been domesticating the perennial forage grass intermediate wheatgrass (IWG) since 2011 using a combination of conventional methods and modern breeding tools such as genomic selection. Globally, most IWG selection nurseries are spaced-planted individuals of several hundred genotypes whereas commercial fields established for grain production are row-planted panmictic populations. In this study, yield and agronomic performance of row-planted IWG half-sib families were assessed over 3 years and 2 locations, Lamberton and St. Paul, MN, USA. The strongest trait correlation was negative (r = -0.49) between 2023 St. Paul height and 2022 St. Paul seed size. The three St. Paul environments were more similar for plant height and seed size and so were the Lamberton environments yet no specific trend was observed for grain yield. Evaluation of different univariate and multivariate genomic prediction models showed that multivariate models outperformed the best univariate models by 23 percentage points, yet no single multivariate model was the best predictor of all traits. Cross-environment predictions were the best among St. Paul environments and no single environment was the best predictor of the remaining environments. Genetic gain estimates indicated a 11 g increase in grain yield and 3 cm reduction in plant height per breeding cycle. While not all traits were predicted with high accuracy, results obtained in this study suggest that evaluation of IWG sibs in row plots followed by trait predictions could lead to substantial breeding progress for desired traits.