Root tube study - Seven strains of Poa and two cultivars of bentgrass (Penncross and Provindence) were grown in the greenhouse in 1 1/4 x 11 inch tubes and maintained at four different mowing heights (1/8", 1/4", 3/8", and unmowed) during spring'96. Each treatment was replicated four times for each entry. Comparisons among entries showed that some Poas had shoot densities that were 8 to 10 times that of either bentgrass under the 1/8"mowing height (Fig. 1A). The two bents had decreasing tiller density at mowing heights less than 3/8'' whereas Poas typically had increased tiller densities under 1/4" compared to 3/8" or unmowed heights and showed only slight decreases under 1/8". Rooting depth of the bentgrasses was consistently greater than that of any of the Poas with the exception of RR 8G-2 under 3/8", 1/4", and 1/8" (Fig. 1B). The unusual rooting characteristics of RR G-2 is being investigated further and this entire experiment is presently being repeated (Fall '96). Results of the crossing experiments above have suggest that the unusual growth characteristics of RR 8G-2 is not being controlled by the plant's genetic mechanism. Other possible causes include the of involvement of micro-organisms. Current investigation is focused on the presence of micro-organisms including fungal endophytes, bacterial endophytes, mites, and viruses.

Cold tolerance screening - This project benefited greatly from the research efforts of Ms. Julie Dionne - a visiting scientist from Laval University, Quebec. Ms. Dionne worked on this aspect of the project for three months (July, August, and September). A new method of screening Poa strains for cold temperature tolerance was developed. This technique uses tissue maintained at a green's height of cut and will be useful for future selection of germplasm resources. Attempts were made to develop methods for screening for tolerance to ice coverage but with no identifiable results, i.e. every sample survived.

Synthetic seed production - A collaborative research project has been initiated with Steve Bowley's lab at University of Guelph, Ontario. Dr. Bowley's lab has optimized the production of synthetic seed for use in alfalfa and is currently researching the application of this technology to forage orchardgrass. The application to grasses has been one of his graduate students project - a Ms. Holly Brittain. Ms. Brittain will complete her M.S. in Dec 96 and finish her employment in May '97. After which we hope to attract Ms. Brittain to Penn State for her Ph.D. graduate education. Her project would likely focus on the production of synthetic seed in Poa annua. To this end I have sent a range of Poa to Guelph to be screened for their potential of producing embryonic tissue in cell culture. If successful, then we will begin to investigate the production of synthetic seed in Poa annua.

DNA content analysis - The 2C nuclear DNA content of leaf nuclei was determined from Poa samples collected from central PA, Maryland, and Virginia and were found to be not significantly different among population locations. However, the DNA content of samples within populations varied greatly (Fig 2). In only one case to date have we found any evidence of polyhaploidy (i.e. 2n=2x=14 chromosomes). Thus, nearly all of the observed variation was within the 2n=4x=28 chromosome level. This project served as part of undergraduate Lane Tredway's Honors project. Preliminary results have also suggested that a positive correlation exits between leaf texture and DNA content (data not shown).