Breeding apomictic bahiagrass (Paspalum notatum Flügge) with improved turf traits

Abstract

The development of a turf‐type bahiagrass could have a remarkable impact on the billion‐dollar turf industry in the south‐eastern United States. The goals of this study were to (i) select bahiagrass genotypes with improved turf attributes and (ii) determine the reproductive mode and seed fertility of selected genotypes. The population included mutants, wild types, hybrids and standard cultivars evaluated at two locations for two years. Morphological variation was observed and clonal repeatability (H2) ranged from 0.27 to 0.90. Flowering was extremely reduced in some mutants, which also exhibited dark green colour, finer texture and reduced canopy height. Cytoembryological observations revealed that diploids reproduced sexually and tetraploids by obligate or facultative apomixis. Genotypes with superior seed fertility were identified, while others were comparable to the standard cultivars. While mutant plants exhibited great morphological variation, the random mutations did not affect their reproductive mode, validating the use of mutagenesis in apomictic species. The high H2 indicated that selection for improved turf attributes could be successfully performed with the advantage of clonal seed propagation.

Managing forage and turf‐type bahiagrass for seed production

“…The correlation analysis indicated that prolific inflorescence production will result in greater bahiagrass seed yield, as previously reported (Adjei & Mislevy, 1987; Adjei et al., 1992), but smaller seed size and lower germination would be expected when more inflorescences are produced. The positive relationship between seed weight and germination reported here and in previous studies (Adjei et al., 1992; Gates & Burton, 1998; Zilli et al., 2018, 2019), together with high heritability for both traits (Rios et al., 2017; Zilli et al., 2019), will be of great utility for breeding purposes.…”

“…The University of Florida bahiagrass breeding program selected advanced tetraploid breeding lines that showed promise for extended forage production (Acuña et al., 2009; Acuña, Blount, Quesenberry, Kenworthy, & Hanna, 2011) and improved turf applications (Pereira et al., 2017; Rios, Blount, Kenworthy, Acuña, & Quesenberry, 2013; Rios et al., 2017). Argentine and the improved forage‐type hybrids were classified as obligate apomictic (Acuña et al., 2009), meaning that they only produce apomictic seed (exact clones of the mother plant).…”

“…2013). The forage‐type breeding lines were expected to respond similarly to Argentine under seed production management, due to their similarities in plant architecture; however, the turf‐type breeding lines may respond differently due to shorter canopy and greater tiller density (Rios et al., 2017). Adequate seed production in these improved lines is critical for considering cultivar release(s).…”

Phenotypic plasticity of aposporous embryo sac development in Hieracium praealtum

“…and Panicum maximum. [16][17][18][19][20] In apomictic Paspalum malacophyllum, aposporous embryo sac and parthenogenetic embryo development seem to outcompete the sexual pathway in relation to embryo sac growth rates and seed types formed. 19 Other factors such as gene deregulation and ploidy levels have also been suggested to promote aposporous embryo sac growth in Paspalum.…”

Transference of natural diversity from the apomictic germplasm of Paspalum notatum to a sexual synthetic population

“…P. notatum is not the exception because low seed germination levels, due to seed dormancy, have been reported as an important limitation for its adoption as a forage species (West & Marousky, ). However, a high variability for seed set and germination have been observed in P. notatum , especially for sexually reproducing genotypes (Acuña, Blount, Quesenberry, Hanna, & Kenworthy, ; Acuña et al, ), which would be very useful for breeding programmes, especially taking into account the high heritability reported for seed set and seed emergence in the species (Rios et al, ).…”