Local adaptation and broad performance are synergistic to productivity in modern barley

Authors: Ewing, Patrick; KANTAR, MICHAEL - University Of Hawaii; KILLIAN, ERIK - Montana State University; Neyhart, Jeffrey; SHERMAN, JAMIE - Montana State University; WILLIAMS, JESSICA - Montana State University; LACHOWIEC, JENNIFER - Montana State University; EBERLY, JED - Montana State University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2023
Publication Date: 1/25/2024
Citation: Ewing, P.M., Kantar, M.B., Killian, E., Neyhart, J.L., Sherman, J., Williams, J., Lachowiec, J., Eberly, J. 2024. Local adaptation and broad performance are synergistic to productivity in modern barley. Crop Science. 64(1):192-199.

Interpretive Summary: Growers benefit when they can plant varieties that are highly adapted to their specific conditions. However, because breeding is expensive, most breeders release broadly adapted varieties that perform acceptably well across target regions. We test whether these needs are compatible – whether lines can be both excellent performers across regions and especially productive in specific conditions. We used a model population of 2-row malting barley, S2MET, which contains modern, elite genetics and was grown across the northern US and Canada. We found that variety selection is essential – most lines were among the 10% best-performing at some locations and the 10% worst-performing at others – but breeding programs do favor broadly adapted genetics. Still, the best performing lines overall were also specialists and overall performance was positively correlated with specialization. This suggests that releasing broadly excellent, locally exceptional varieties is a viable goal for regional breeding programs that may also better meets grower needs.

Technical Abstract: Crop populations have enormous impacts on agricultural productivity, yet decelerating gains from breeding suggest that selection strategies need to be reconsidered to better align priorities of breeders and growers. Breeders benefit from releasing broadly adapted varieties that perform acceptably well across their target region; growers benefit from selecting a variety that specializes in their specific location. We tested whether these incentives are compatible using the mega-population of 2-row malting barley (Hordeum vulgare L.), S2MET, which was grown across the northern United States. We assessed the strength of genetic-environment interactions (GxE), quantified local adaptation benefits, and tested whether local adaptation and genetic yield potential were correlated. Despite evidence that breeding programs favored broad adaptation (p < 0.001), most cultivars were both among the top 10% best performing at some locations and among the worst 10% at others. Some of the best overall cultivars were specialists, performing especially well in their home locations, and in general, genetic potential and local specialization were positively correlated (p < 0.001). These results suggest that breeding for local performance and broad performance are mutually supporting goals. Releasing broadly excellent, locally exceptional varieties may accelerate genetic gain to meet projected global agricultural demand.