Crop improvement in bahiagrass (Paspalum notatum Flüggé) is limited by apomixis in most natural tetraploids, however, diploid sexual types occur. Production of sexual tetraploids by chromosome doubling will allow hybridization with apomictic tetraploids. Diploid bahiagrass (Paspalum notatum Flüggé) embryogenic callus tissue was exposed to three concentrations of three antimitotic chemical agents, colchicine, oryzalin and trifluralin. Callus was generated to plants and ploidy was evaluated by stomata size, mitotic chromosome counts, and flow cytometry. A total of 310 plants were verified as tetraploid of 1,432 plants that reached transplanting size. All treatments yielded 4x plants. The mean percentage success over all treatments was 22%, with means of 31% for oryzalin, 24% for colchicine and 16% for trifluralin. The high rates of success indicate that all agents can be successfully used to double chromosome numbers in bahiagrass. The percentage of 4x plants ranged from 9% (20 lM trifluralin) to 43% (20 lM oryzalin). Several treatments adversely affected regeneration. Mitotic chromosome counts are difficult and labor intensive in bahiagrass. Therefore, leaf stomata measurements were used as a preliminary screen. Data gave a bimodal distribution with overlapping tails and based on chromosome counts would have given an error rate of 12%. Flow cytometry analysis of regenerated plants resulted in mean nucleus fluorescence distributions consistent with control diploid or tetraploid values. These values agreed with chromosome counts, and this method is recommended for determining bahiagrass ploidy level. Research goals and available resources should be taken into consideration when selecting a treatment for chromosome doubling in bahiagrass.

Identification of forage legumes well adapted to the southeastern United States is complicated by climatic, soil, and biotic factors. Among the pests that impact forage legume persistence are root‐knot nematodes (RKNs) (Meloidogyne spp.). We hypothesized that legumes native to the region should have higher levels of resistance to RKN species that are common in this region due to long‐term natural selection pressure. The objective of this research was to evaluate the response of 10 southeastern U.S. native legumes to M. arenaria (Neal) Chitwood race 1, M. incognita (Kofoid and White) Chitwood race 3, and M. javanica (Treub) Chitwood. Legumes were grown in Cone‐tainers in a greenhouse for 3 wk, inoculated with a given RKN isolate, and after an additional 9 wk were uprooted and evaluated for root galling and nematode egg mass production responses. The level of root galling and egg mass production varied among native legumes, but in general was lower than previously observed on introduced legumes. Desmodium paniculatum (L.) DC., Galactia regularis (L.) Britton et al., and Centrosema virginianum (L.) Benth. varied among the three RKN species in their root galling and egg mass production responses. The accession of D. incanum DC. used was immune to all three RKN isolates, and could be a potential source of RKN resistance genes. The perennial native legumes evaluated all had either a fleshy taproot or a strong rhizome system.