Genetic gains and genotype‐by‐environment interaction in turf bermudagrass drought resistance improvement in the southern United States

Abstract Breeding bermudagrass ( Cynodon spp.) involves creating progeny combining multiple desired traits from hybridization and ensuring their adaptation and performance to various environments through rigorous testing. Turfgrass breeding programs in the southern United States collaborated to breed new bermudagrass lines for drought resistance. Thus, the objectives of this study were to evaluate advanced bermudagrass lines and to characterize their genetic gain in performance traits, reliability, genotype‐by‐environment interaction (GEI), and stability. The study, encompassing 34 advanced lines and three standard cultivars planted in randomized complete block designs with three replications, was carried out at eight locations across the southern United States from 2020 to 2023. Experimental lines OSU2073, OSU2081, OSU2082, TifB20201, and TifB20205 showed improved drought response relative to the drought resistant cultivar TifTuf with significant genetic gain in the mega‐environment (a group of locations that share similar environment conditions in which a crop has consistent performance across them) of Dallas, TX, and Stillwater, OK. Substantial GEIs were observed under drought stress across the southern United States. This study highlights the continuous genetic gain made in breeding efforts to improve drought resistance of bermudagrass and identifies new cultivar candidates for conserving irrigation water to the turf industry.