Breeding procedures developed for apomictic species are based on the idea of fixing superior hybrids by apomixis. However, scarce information is available about the occurrence of heterosis in apomictic hybrids. The objective was to generate a group of apomixis‐segregating tetraploid bahiagrass (Paspalum notatum Flüggé) families, evaluate the occurrence of heterosis for a series of agronomic and morphological traits, determine the level of apospory expressivity among hybrids, and estimate the genetic distance among parents and its relationship to heterosis and apospory expressivity. In total, 11 tetraploid families were generated by crossing sexual and apomitic genotypes. The segregation for mode of reproduction was analyzed using a random amplified polymorphic DNA (RAPD) marker linked to apospory in bahiagrass, and the level of apospory expressivity was determined using embryo sac observations. The genetic distances between parents were determined using inter‐simple sequence repeat (ISSR) markers. The ratio between sexual and aposporic hybrids varied from 1:1 to 7:1 among families. Discontinuous variation for apospory expressivity was observed in the hybrids, with either low or high levels being exhibited. Midparent, high‐parent, and standard heterosis was observed for all evaluated characteristics. The level of heterosis was dependent on the combination of parents involved and also on the specific trait. There was a low correlation between genetic distances among parents and initial growth and the level of apospory expressivity. The occurrence of heterosis and the segregation and expressivity for apospory were highly dependent on the combination of sexual and apomictic parents.

The objective of this review is to analyze and describe the impact that mode of reproduction in Paspalum has on germplasm conservation, genetic improvement, and commercialization of cultivars. Germplasm collection and conservation can now be rethought considering the newly available information related to how diversity is allocated in nature and how it can be transferred between the sexual and apomictic germplasm using novel breeding approaches. An inventory of species and accessions conserved around the world is analyzed in relation to the main germplasm banks. Because of the importance of apomixis in Paspalum species different breeding approaches have been used and tested. Knowledge related to the inheritance of apomixis, variable expressivity of the trait and techniques for early identification of apomicts has helped to improve the efficiency of the breeding methods. Novel breeding techniques are also being developed and are described regarding its advantages and limitations. Finally, the impact of reproductive mode on the adoption of the released cultivars is discussed.

Bahiagrass (Paspalum notatum Flüggé) is one of the main components of the South American grasslands, and it is cultivated for forage and turf around the world. At present, hybridization is the most common breeding technique for the species, and its goal is to obtain superior apomictic hybrids. The objective of the present study was to determine the relationship between heterosis, reproductive behavior, and genetic distances between parents in tetraploid bahiagrass. Genetic distance between 24 sexual tetraploid genotypes and 24 apomictic tetraploid genotypes of P. notatum was evaluated using simple sequence repeat (SSR) and inter simple sequence repeat (ISSR) markers. Crosses were made between parents with low, intermediate, or high genetic distances. Six families were generated. A marker linked to apospory in bahiagrass was used to determine segregation for mode of reproduction, and embryo sacs were characterized to estimate the level of apospory expressivity. The ratio between sexual and aposporous hybrids ranged from 1:1 to 9:1 among families. Discontinuous variation for apospory expressivity was observed among hybrids, with either low or high levels being exhibited. A significant relationship between genetic distance and proportion of aposporous hybrids was observed. Heterosis was observed for all the evaluated traits and its level was dependent on the parental combination. Genetic distances between parents were related to heterosis, mainly for forage yield, which is the most important trait in forage species. Hence, molecular markers may be useful to predict the occurrence of heterosis for this trait.

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In natural ecosystems, plants appear to be in symbiosis with diverse fungal endophytes which can have impacts on plant communities. Paspalum is one of the most important grass genera in South American grasslands. The aim of this work was to determine the presence of fungal endophytes in two Paspalum species and evaluate their effects on plant growth. Sixty plant samples were collected for Paspalum notatum in a rangeland in northeastern Argentina, and the same number for Paspalum dilatatum in central Argentina. A triple‐sterilization process was carried out by submerging small pieces of leaves and stems for the isolation of fungi from the collected plants. In order to identify endophytes, morphological characters and fungal sequences corresponding to the ITS (Internal Transcribed Spacer) region were analysed. A total of eight genera were identified: Acremonium, Alternaria, Aspergillus, Bipolaris, Cladosporium, Fusarium, Penicillium and Trichoderma. A greenhouse trial was conducted to determine the effects of fungal endophytes on growth. Trichoderma significantly increased relative chlorophyll content in P. notatum and Acremonium endophytes increased tiller number, and above‐ and below‐ground biomass in P. dilatatum. The diversity of fungal endophytes that was present in P. notatum and P. dilatatum was described. In conclusion, some aspects of growth of these Paspalum species seem to be positively affected by Trichoderma and Acremonium.