Defoliation management affects seed production of tetraploid bahiagrass

Bahiagrass ( Paspalum notatum Flügge) is an important forage and turf crop, but limited seed production remains a challenge to release of tetraploid cultivars. Defoliation intensity at the onset of the reproductive phase of some grasses influences tillering, seed head production, and seed yield. Thus, our objective was to quantify seed yield components and seed yield of elite tetraploid bahiagrass entries following clipping to 5‐ and 10‐cm stubble heights in spring. Our hypotheses were that shorter stubble height increases seed yield and differences in seed yield potential exist among tetraploid entries. The trial was conducted in Gainesville, FL, from 2022 to 2024. Treatments were allocated to four replicates of a randomized complete block design with a split‐plot restriction to randomization. Spring defoliation intensities (5‐ and 10‐cm stubble heights) were main plots, and entry subplots included nine advanced tetraploid bahiagrass experimental lines plus Argentine as a control. Agronomic (forage mass, tiller and seed head density, reproductive differentiation, and seed yield) and seed quality traits (filled seed yield, seed set, weight of 1000, and seed viability) were evaluated. There was a fourfold difference in seed yield among entries. The 5‐cm height increased seed yield through increased seed head density for all entries, however only Hybrid 93 had greater filled seed yield at the 5‐cm height (58 ± 9.3 kg ha −1 ; 131% greater). All entries were similar to Argentine in seed viability. The 5‐cm height increased seed yield relative to the 10‐cm height, and entries varied widely in seed yield potential.