Development of Intergeneric Hybrids of Ryegrasses with Fescues as New Stress Tolerant Turfgrasses.

We have developed a population of turf-type intergeneric hybrids of Lolium and Festuca, or Festulolium with a capacity to survive without supplemental irrigation in southern California. We continue to select in the populations of perennial ryegrass, L. perenne, x meadow fescue, F. pratensis, hybrids for the best combinations of turf quality, seed yield, and resistance to stress, specifically drought, heat, and salinity. After two rounds of selection in the field, plants were karyotyped and 60% chromosomes 3 present (the satellited chromosome in the L. perenne karyotype) had an F. pratensis introgression on the short arm. Few other introgressions were also present, but no specific pattern was apparent. The relationships between similar introgressions and resistance to abiotic stresses have already been documented for forage-type Festuloliums and we believe that extreme selection applied to our materials favored the specific genome regions from F. pratensis. Since we already have sub-populations of L. perenne with the presence/absence of certain segments of F. pratensis chromatin, we are using these sub-populations to associate DNA polymorphism with specific chromosome segments. At present, the cheapest and the simplest approach is to use the Diversity Arrays Technology (DArT). It has recently been extended to grasses in general; we propose to extend it to turf. DNA from individually karyotyped plants were extracted and sent for analyses to establish which markers co-segregate with which segment. This was done in two separate populations, for verification of results. We expect to end up with sets of DNA markers for each segment of F. pratensis chromatin that is critical for stress tolerance. We will convert these DArT markers to PCR-based markers for marker-assisted selection in turfgrass breeding programs.