Conservation analysis of apospory specific genomic region, (ASGR) in tetraploid races of Paspalum notatum

REBOZZIO, R.; ORTIZ, J. P. A.; QUARIN, C. L.; ESPINOZA, F

Buenos Aires

Simposio; The 6th International Symposium on the Molecular Breeding of Forage and Turf; 2010

Paspalum notatum Flügge (bahiagrass) was considered an excellent native forage grass long before it became a cultivated species. It has an extremely versatile reproductive system with sexual self-fertile diploids and pseudogamous apomictic autopolyploid. Genetic linkage maps for diploid and tetraploid cytotypes of the species are available and several molecular markers cosegregating strictly with apospory were identified (18 AFLP, 2 RAPD and 1 SCAR (SPNA1). The ASGR of the species is a large non-recombinant genomic region that could span 36 Mpb. The objective of this work was to estimate the consistency of the molecular markers associated with apospory in tetraploid races of the species from different geographic origins. Thirteen apomictic genotypes from 7 different countries of South America were assayed. As controls the tetraploids sexual Q4188 and apomictic Q4117 genotypes were used along with 8 and 36 aposporous and non-aspororous F1 plants derived from them. AFLPs analysis was carried out using 12 specific primers combinations. Amplifications products were separated on 6% denaturing polyacrylamide gel. Markers SPNA1 and RAPDs UBC-243 and UBC-259 were generated using primers and PCR conditions stated previously for each marker. DNA fragments associated with apospory were identified by its corresponding base pairs length and by comparison with the amplicons originated from the apomictic parent Q4117. Molecular analysis showed that all markers were present in the apomictic parent, its apomictic F1 progenies and in the 13 apomictic natural accessions. These bands were always absent in the control sexual genotype Q4188 and in the 36 non-aposporous F1 plants. The overall results showed that all the 21 molecular markers linked to the ASGR in Q4117 were conserved in all natural races of P. notatum tested. This finding indicated that the ASGR of the species has a high level of conservation across genotype from distant geographic origins. Markers assayed in this study constitute a valuable tool for using tagging the reproductive mode in breeding programs of P. notatum.