Gain from genomic selection for a selection index in two-row spring barley

Area of Science:

• Plant breeding
• Quantitative genetics
• Agricultural science

Background:

• Genomic selection (GS) offers potential to accelerate genetic gain in new breeding programs.
• Selection index (SI) combines multiple traits, but empirical studies comparing GS and phenotypic selection (PS) on SI values are limited.

Purpose of the Study:

• Compare genetic gain in overall SI value for malting barley using GS versus PS.
• Evaluate the impact of GS on genetic variance and inbreeding for multiple traits.

Main Methods:

• Two cycles of GS and one cycle of PS were implemented in two-row spring malting barley.
• Selection was based on overall SI values for height, heading date, preharvest sprouting (PHS) resistance, and spot blotch resistance.

Main Results:

• GS achieved higher realized gain for SI value, height, and PHS compared to PS.
• GS did not significantly improve gain for heading date and spot blotch resistance.
• GS substantially reduced genetic variances for heavily weighted traits (PHS, germination) and increased inbreeding, though restricted mating mitigated this.

Conclusions:

• Genomic selection is a valuable tool for accelerating genetic gain on selection index values in malting barley.
• GS is effective for traits with higher index weights, such as PHS resistance.
• Managing inbreeding is crucial when implementing GS in breeding programs.