A genetic linkage map of diploid Paspalum notatum

Paspalum notatum Flugge is a subtropical grass native to South America. The most common form in the USA is P. notatum var. saurae Parodi (Pensacola ba hiagrass), which is a valuable forage. Pensacola bahiagrass is a sexual dip loid, while most other races of P. notatum are apomictic tetraploids. The o bjective of this work was the construction of a genetic linkage map of dipl oid P. notatum (2n = 2x = 20) that can be used as a framework for basic gen etic studies as well as breeding purposes. The mapping population derived f rom a cross between the genotypes Q4084(10) and Tift(9) that originated fro m Cayasta, Santa Fe, Argentina, and Tifton, GA, USA, respectively. Heterolo gous restriction fragment length polymorphism (RFLP) clones of maize (Zea m ays L.), rice (Oryza sativa L.), and oat (A vena sativa L.) were used to co ver the Paspalum genome uniformly in a comparative approach, while random a mplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers were added to condense the linkage groups. A combined map wa s constructed with the markers segregating from both parental genotypes by the program JoinMap 1.4. A total of 149 marker loci were used for map const ruction. One hundred twelve loci were allocated to 10 linkage groups, cover ing a total map distance of 991 centimorgan (cM). The average distance betw een markers was about 9 cM. Paspalum Linkage Groups 1, 3, 4, 5, 6, 8, and 1 0 showed syntenic regions with maps of maize and rice. Moreover, several RF LP loci reported to be associated with apomixis in hybrids of maize-Tripsac um and Brachiaria were located on the map. This study provides a genetic li nkage map of a subtropical forage grass with both sexual and apomictic form s, which can be used for investigating simple and complex traits.