Early-stage evaluation of grazed tetraploid bahiagrass experimental entries

Bahiagrass (Paspalum notatum Flugge) cultivars used for forage in the southeastern United States are primarily diploids. Although producers favor tetraploid traits, for example, wider leaf blades and fewer inflorescences, compared to diploids, there are barriers to their greater use, including apomictic reproduction, lesser frost tolerance, and later initiation of spring growth. By overcoming the apomixis barrier, viable tetraploid options are now available. This study compared annual and seasonal forage accumulation (FA), persistence, and nutritive value of nine tetraploid experimental entries and 'Argentine' under 'moderate' (10-cm stubble, 4-week grazing interval) and 'intensive' grazing (5-cm stubble, 2-week grazing intervals) during 2020 and 2021. More upright-growing entries, such as Hybrids 3 and 93, had greater annual FA than Argentine (8230 and 9160 vs. 6060 kg DM (ha year)(-1)). Similarly, Hybrids 3 and 93 were 50% more productive in early and late season than most entries. Decumbent entries had 30% greater FA under intensive than moderate grazing, whereas upright types generally had similar FA for both grazing managements. Most entries had comparable digestibility and crude protein as Argentine (similar to 503 and 124 g kg(-1), respectively), and intensive grazing resulted in greater nutritive value than moderate grazing, regardless of entry. All entries maintained high ground cover across grazing treatments (88%-96%). The most striking difference was the superior annual FA and the seasonal distribution of FA for Hybrids 3 and 93 compared with other entries, particularly during spring and fall. This occurred without compromising persistence or nutritive value. Five entries showed superior traits compared to Argentine and should be selected for further evaluation under greater spatial and temporal scales prior to cultivar release.