Construction of a genetic linkage map of tetraploid apomictic Paspalum notatum

STEIN, JULIANA; PESSINO, SILVINA C.; MARTÍNEZ, ERIC J.; QUARIN, CAMILO L.; ORTIZ, JUAN P. A.

Carlos Paz. Córdoba, Argentina

Congreso; XXXVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2002

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Apomixis is a genctically-determined asexual mode or rcproduction of flowering plants that leads to the formation of clonal embryos. Our work was aimed at the construction of a full genetic map of tetraploid Paspalum notatum in order to locate the locus/loci governing the trait in the species. A highly heterozygous F1 mapping population of 115 individuals was generated by crossing a sexual genotype (Q4188) and an obligate apomictic genotype (Q4117). The mode of reproduction of the F1 individuals was determined by both cytoembryological studies and RAPD-based progeny tests. A core genetic map was generated by using AFLP molecular markers. Segregation data originated from the male and female parents were analysed by using the JoinMap 1.4 computational package. Several molecular markers fully or partially linked to apomixis were identified. Fragments completely linked were eluted, reamplified, cloned and sequenced. Several additional RAPD and RFLP markers that had heen associated with the character in this and other species were also included in the map. Our results indicated that the trait is controlled by a single locus in P. notatum. The gene/genes involved present a segregation distortion probably related to a partial lethal effect and is/are included in a region showing a strong restriction of recombination. Markers identified here could be used in a future work aimed at the isolation of the gene/s governing apomixis by map positional cloning.