Quantitative analysis of apospory and parthenogenesis in diploid hybrids and autotetraploid genotypes of Paspalum rufum.

SOLIMAN M.; DEMARCHI LD; ZULIANI J; ESPINOZA F; ORTIZ JPA; DELGADO L

Foz do Iguazu

Congreso; Inter Congress of Genetics; 2018

Apomixis is a clonal reproduction pathway by seeds strongly linked to polyploidy. Its transference to commercial crops promises an opportunity to fix superior genotypes and hybrid combinations. Some diploid P. rufum genotypes contain aposporous embryo sacs and show apomixis ability. Moreover, ybridization and polyploidization induced higher apospory expressivity (%AES) in thisspecies. The understandings of apomixis components (apospory and parthenogenesis) transmission in a diploid background and of the influence of polyploidy are key points for transferring the trait to diploid crops.Our objectives were to evaluate apospory stability over the time and its expressivity in F1 andF2 progenies. Moreover, we tested apomixis expression in F1 and autopolyploid individuals obtained after chromosome doubling of diploids with and without capability to complete apomixis.The %AES and parthenogenesis were quantified by cytoembriology and flow cytometric analysis, respectively. Autotetraploids were generated by colchicine treatment of diploid seeds. F1 individuals with higher %AES (~35%) showed a decrease in the expression of the trait over time (~8%). On the other hand, F2 progenies showed similar %AES than their parental genotypes. Autopolyploid individuals produce similar %AES to their diploid counterpart, in contrast to previous results. Parthenogenesis was transmitted to some F1 diploids, but to all autotetraploids. Moreover, autotetraploids presented higher apomixis ability than their diploid counterpart. Results showed that %AES could be transmitted to advanced generations and is highly influenced by environmental conditions. Apomixis ability is increased by polyploidization, and seems not to be associated with the %AES or the apomixis ability of original diploid genotypes.