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

Abstract

Genetic improvement in apomictic forage species has been restricted because of the absence of genetic variability in sexual germplasm with the same ploidy level. Following a new breeding scheme, a sexual synthetic tetraploid population (SSTP) of Paspalum notatum has been generated. The objectives of this work were: (a) to evaluate the genetic variability in SSTP by means of molecular markers, morphologic and agronomic traits, and seed fertility and quality traits and (b) to assess the transference of genetic variability from the apomictic germplasm to the sexual one. Molecular markers revealed a twofold higher level of variability in the SSTP in comparison with the sexual germplasm utilised for its generation, and similar levels with the apomictic ones; moreover, markers showed that most of the variability was inherited from the apomictic germplasm. Morphologic and agronomic traits and seed fertility and quality traits showed high levels of variation in the three groups of genotypes indicating that the new breeding scheme was effective in transferring variability from the apomictic germplasm to the SSTP. This new population will be useful in breeding of P. notatum, and the breeding scheme used for its generation may be used in other apomictic species. K E Y W O R D Sfertility, genetic improvement, genetic variability, microsatellite markers, sexuality

Recurrent phenotypic selection and recurrent selection based on combining ability in tetraploid bahiagrass

“…This greater increase in forage yield than in Burton (1974) may be related to the selection intensity used, which in our work was 3%, whereas in Burton (1974) it was 20%. This difference may be associated with the fact that we used a highly diverse sexual base population (Zilli et al., 2019), and also with environmental differences between experiments. In addition, this method was effective to improve Medicago sativa L. (lucerne), a forage legume (Dudley, Hill, & Hanson, 1963).…”

“…The diversity present in the apomictic ecotypes was successfully transferred to the SSTP, as demonstrated using molecular and morphological markers by Zilli et al. (2019).…”

“…Then, F 1 hybrids were classified by their mode of reproduction as sexual or apomictic. The most diverse sexual hybrids were selected and polycrossed, and a sexual synthetic population characterized by its wide diversity was obtained (Zilli et al., 2019). Since sexuality behaves as a recessive trait in bahiagrass (Martínez et al., 2001), it is possible to maintain this mode of reproduction in a sexual synthetic population over breeding cycles (Zilli et al., 2018).…”

“…Considering the importance of heterosis for breeding apomictic species and the availability of a highly diverse sexual synthetic tetraploid population of P. notatum (Zilli et al., 2019), new breeding techniques could be developed to improve the tetraploid germplasm of bahiagrass. Cycles of selection and crosses between the sexual synthetic population and apomictic genotypes could be implemented and thus obtain progenies with superior characteristics.…”

New records and range expansion for Paspalum procurrens and P. volcanense in northwestern Argentina and southeastern Bolivia

“…Furthermore, considering the ecological amplitude found among species, and the reproductive, morphological, and genetic variability present in the group (Zuloaga and Morrone 2005), Paspalum is of scientific interest for a variety of studies, including topics on evolution, like the origin and distribution of new apomicts (e.g. Hojsgaard 2018) and applied agronomy, like breeding of native forages (Marcón et al 2018;Zilli et al 2018Zilli et al , 2019. Many Paspalum species are characterized by the existence of conspecific cytotypes, i.e.…”