Genomewide Selection in Rice ( <scp> <i>Oryza sativa</i> </scp> L.) Breeding: Balancing Cost and Time for Higher Genetic Gain

ABSTRACT In rice ( Oryza sativa L.), genomewide selection and field‐based rapid generation advancement (FRGA) are two ways to increase genetic gain. Our objective was to assess genetic gains from genomewide selection coupled with FRGA in a rice breeding pipeline. Per‐unit breeding costs were estimated for crossing, generation advancement, phenotyping and genotyping. One‐ and two‐cycle genomewide selection schemes were simulated and were compared with phenotypic selection via single seed descent. Results showed that two‐cycle genomewide selection with FRGA achieved the largest genetic gain. This outcome was obtained with 300 Cycle 0 F 2 plants, 300 Cycle 1 F 2 plants, 100 lines in on‐station yield trials, 50 lines evaluated across two locations in advanced yield trials and a predictive ability of 0.80. This gain represented 167% of the maximum gain from phenotypic selection and 141% of that from one‐cycle genomewide selection. Genomewide selection schemes with FRGA reduced breeding cycle time by 15%–28% compared to phenotypic selection. Our findings suggest that two‐cycle genomewide selection with FRGA is a time‐ and cost‐efficient strategy for increasing genetic gain in rice breeding.