A core AFLP map of aposporic tetraploid Paspalum notatum (Bahiagrass)

ORTIZ JPA; STEIN J; MARTINEZ EJ; PESSINO SC; QUARIN CL

Aberystwyth, Gales, Reino Unido

Workshop; XX International Grassland Congress; 2005

Paspalum notatum (Bahiagrass) is a perennial rhizomatous species that reproduces by aposporous apomixis. Tetraploid races (2n=4x=40) are widely distributed from Central to South America and constitute one of the most valuable natural forage grass for the subtropical areas of Paraguay, south of Brazil and north-eastern Argentina. The objectives of this work were to develop of a core genetic linkage map of the species by using AFLP markers and characterize the genomic region related to apospory. A total of  119 markers segregating from the male parent were used for the linkage analysis. A core AFLP map was built with 146 markers distributed in 22 linkage groups. The total genetic map distance covered was about 1,430 cM, with an average of approximately 10 cM between markers. The linkage group carrying the locus for apospory (apo-locus) was defined by 28 loci on 32 cM. Twelve markers resulted completely linked to the apo-locus, while the rest showed recombination values between 0.6 and 18 cM, at both sides of it. The complete co-segregation of several markers and apospory confirmed the suppression of recombination in this genomic region reported by Martínez et al. (2003). The average distance between markers in the apo-group was about 1 cM.  A core genetic linkage map of aposporous tetraploid P. notatum was built with AFLP markers. It can be employed for fundamental research as well as for localising genes of agronomic interest.