Germination and Growth Rate Differences Among Kentucky Bluegrass Cultivars

Kentucky bluegrass (Poa prantesis L.) is the most widely used cool-season turfgrass in athletic fields, but it is slow to germinate from seed. Rapid germination of seed is essential for athletic field managers to quickly establish and recover fields from athlete wear and traffic to increase the safety of the playing surface. Based on recent plant breeding efforts, improved Kentucky bluegrass cultivars may aid in faster germination and recovery. Two studies were completed to assess the germination and growth of modern Kentucky bluegrass cultivars. The objective of the first experiment was to determine the germination rate, seedling vigor, and seed phenotype of 21 cultivars. Standard germination tests were conducted using blotter paper, petri dishes, and a seed incubator. Twenty-one cultivars were tested across two seed lots. Germination was most rapid among the experimental genotype PST-T15-44 and the commercial cultivar After Midnight, as they took the fewest days to reach 50% germination in only 7.9 or 8.8 d, respectively, with ‘Tirem’ and ‘Volt’ requiring \u3e12 d in both runs to reach 50% germination (12.0 to 13.7 d). These results point to a 5 d to 6 d difference in germination. A paper towel test also measured the seedling vigor of 21 cultivars, but few differences between cultivars were noted in this test. Seed phenotyping determined that seed length and circularity were correlated with germination rate (r=0.62, P=0.0025; r=−0.53, P= 0.0141; respectively). By identifying and utilizing rapidly germinating Kentucky bluegrass cultivars, it may be possible for athletic field managers to repair damaged turf areas more quickly in between events. The objective of the second experiment was to study the growth of selected Kentucky bluegrass cultivars using classical growth analysis. Six commercially available Kentucky bluegrass cultivars were studied. ‘Barvette HGT’ produced the largest plants and ‘Moonlight SLT’ the smallest plants by the end of the experiment although the relative growth rate (RGR) and absolute growth rate (AGR) did not vary between the cultivars. Final plant weights and leaf area measurements closely aligned with industry information about the classification of these Kentucky bluegrass cultivars, but classical growth analysis provided little insight into why cultivars have aggressive growth (Barvette HGT) characteristics or compact growth habits (Moonlight SLT). Overall, the data from this thesis demonstrates that selecting the right cultivar is an important component to the successful establishment and recovery of Kentucky bluegrass athletic fields