Abstract:
Creeping bentgrass (Agrostis stolonifera L.) is a highly outcrossing allotetraploid
species important to the turfgrass industry because it has unique growth and aesthetic
characteristics that make it ideally suited for use in high quality turf stands. There are
between 150 and 200 species of Agrostis (bentgrasses) and the relationships between
species are not clearly understood. Resolving these relationships is complicated in part
because many of the species share similar morphological features and interspecific
hybridization is common, making taxonomic classification difficult. Knowledge of the
evolution of Agrostis species would provide turfgrass breeders with information on the
origins of species and potential sources of novel germplasm.
In the present study 305 Agrostis accessions were examined to explore the
evolutionary relationships within the Agrostis genus. Flow cytometry experiments were
performed on each accession to measure DNA content and make ploidy predictions.
MITE display molecular markers were designed and 1,309 were used to assess genetic
diversity within a subset of these Agrostis accessions. Fragments of the trnL-trnF and
atpI-atpH intergenic spacer regions of the chloroplast genome were also sequenced and
used to infer the phylogeny of the chloroplast genome. This data allowed for the
prediction of candidate diploid progenitors of cultivated Agrostis species, identification
of geographic regions of diverse germplasm, and demonstration of narrowing of the
cultivated Agrostis gene pool. The data presented here gives Agrostis breeders valuable
information to incorporate novel germplasm in their programs and a direction for
recreating the polyploidization events that have led to the cultivated turf-type Agrostis
species.
