Germination, seedling growth and establishment of warm-season turfgrasses related to climate changes in the Mediterranean region

The Mediterranean region is located from the arid climate of North Africa up to the temperate and rainy climate of northern and central Europe. Climate simulations show a gradual increase in heating, drying and precipitation variability in this region. These effects will probably push warmseason turf species towards minor latitudes. The consequences of climate change on turfgrass management have been investigated only recently. Germination and seedling growth have also been little studied for the response to climate change effects, although the establishment phase is central to any high-performing turfgrass. For warmseason grasses in the transition zone, a quick establishment increases winter survival and allows for earlier spring green-up and a more rapid recovery from winter injury. In the Mediterranean region, warm-season grasses are commonly seeded in late spring when the temperatures are suitable for a rapid establishment. Warm-season species used extensively by the turf industry have fertile and sterile cultivars. Seeded cultivars are usually preferred over sterile cultivars because seeding is cheaper and easier to practice than vegetative propagation methods which include plugging, sprigging, and stolonizing. The present study concerns two of the most used warm-season turf species in the Mediterranean area: Bermudagrass (Cynodon spp.) and seashore paspalum (Paspalum vaginatum Swartz) and one potential future new species i.e.buffalograss [Buchloe dactyloides (Nutt.) Engelm.]. The research activity scheduled consisted of five experiments conducted in the field and controlled environments (growth chamber and greenhouse) to investigate the effects of suboptimal temperatures and excess of water due to flooding on seed germination and seedling growth. The main results were the following: Effects of sub-optimal temperatures The warm-season grasses tested germinated at a temperature equal or higher than 11.4 °C (base germination temperature) and early April is the optimal seeding time for establishing by seed warmseason turfgrasses in the Po-Venetian valley. From these results, we have concluded that the predicted warmer springs should lead to earlier seeding of warm-season grasses favouring turfgrass maturation before winter. Effects of water excess All three warm-season turf species under study tolerate flash waterlogging. However, bermudagrass is the one less affected by prolonged waterlogging (6-8 days). In general, warm-season grasses can be successfully used for establishing turfgrasses considering the future climate change predicting the increase of extreme precipitation events.