Physiology Partially Decoded: Results from Genetic Diversity Screening in a Panel of Seashore Paspalum, a Salt-tolerant Turfgrass

Salt-tolerance is a sought after trait in cultivated cereals, but its absence in the germplasm of many of these species limits our prospects for studying tolerance mechanisms adequately.  However, we believe studying the mechanics of the trait in a halophyte closely related to many cereals would serve as an informative model and may elucidate mechanisms which could be biologically relevant for some members of this important group.  To prepare for further studies in Paspalum functional genomics, we screened a collection of 96 accessions including Paspalum vaginatum, P. distichum, and several other congeners for ploidy level  using flow cytometery and chromosome counting, conducted characterizations of relative growth inhibition under salt stress, and developed a panel of microsatellite markers for use in genetic diversity studies as well as future studies in genetic mapping.  The microsatellite markers were developed from a (GA)_n- and (CA)_n- enriched library derived from Paspalum cultivar ‘Salam.’  The germplasm was screened using PCR amplified SSRs analyzed on an ABI 3730XL and alleles were called with GeneMapper 4.1.  SSR alleles were used to survey this Paspalum collection in order to ascertain the level of genetic diversity present as well as to resolve issues of population structure.   A synthesis of the available data has shown interesting relationships between ploidy level and putative salt tolerance and has revealed interesting patterns of population structure.