Warm-season turfgrass species prevail in tropical and subtropical areas, but can also be grown in the transition zone. In this case, cold tolerance is a key aspect for germination and successful turfgrass establishment. The germination response to sub-optimal temperatures was investigated for Cynodon dactylon (cvs Jackpot, La Paloma, Transcontinental, Yukon, Riviera), Buchloe dactyloides (cv SWI 2000) and Paspalum vaginatum (cv Pure Dynasty). Four temperature regimes were applied, i.e., 20/30 °C, 15/25 °C, 10/20 °C and 5/15 °C, with a 12:12 h (light:dark) photoperiod. Germination assays were performed twice, with six replicates (Petri dishes) per treatment in each experiment, fifty seeds per dish. The final germinated percentages at last inspection time (FGP) were obtained for each Petri dish and processed by using a generalized linear mixed model (binomial error and logit link). Germination curves were fitted to each Petri dish by using time-to-event methods and germination rates (GR) for the 10th, 20th and 30th percentiles were derived and used to fit a linear thermal-time model. For all cultivars, FGP decreased with decreasing mean daily temperatures. Base temperatures (Tb) ranged between 11.4 °C and 17.0 °C, while the thermal time to obtain 30% germination ranged from 51.3 °C day for SWI 2000 to 144.0 °C day for Pure Dynasty. The estimated parameters were used to predict germination time in the field, considering the observed soil temperatures in Legnaro. The estimated date for the beginning of germination in the field would range from early April for SWI 2000 and Transcontinental to mid-May for Riviera. These results might be used as a practical support for planning spring sowing, which is crucial for successful turfgrass establishment, especially without irrigation.

Mixtures of turfgrass species are commonly used throughout the world when establishing cool‐season grasses from seed. However, there have been limited studies investigating how various species compete with each other as the turf matures. A study was conducted in Padova, Italy, to investigate the performance and species composition of four mixtures that contained a single cultivar of Kentucky bluegrass (KB; Poa pratensis L.) and two rhizomatous or two nonrhizomatous tall fescue (TF; Festuca arundinacea Schreb.) cultivars. The trial was seeded in September 2010. Three mowing heights (20, 32, and 62 mm) were also applied to all the mixtures. General turfgrass performance of the mixtures was monitored through the 2011 growing season, and species composition was measured regularly to determine the abundance of both species in the mixture. Throughout the study, the mixtures containing the rhizomatous TF consistently had higher turfgrass quality and turfgrass density than mixtures containing the nonrhizomatous types. Mowing height had less effect on the performance of the mixtures, but the lower mowing heights (20 and 32 mm) performed more consistently than the plots mowed at the highest (62 mm) mowing height. Species composition of the mixtures was significantly influenced by the different TF cultivars, in that KB was less abundant in mixtures containing rhizomatous TF cultivars compared to nonrhizomatous cultivars, suggesting an increased competitive ability of rhizomatous TF lines. Mowing height also influenced the species composition, in that KB was significantly more abundant at lower mowing heights.

Bermudagrass is the most widely used warm-season turf species in the transition zones of Europe. The Venetian valley (northeastern Italy) is a typical transitional zone, characterized by cold winters and hot summers, where the performance of bermudagrass mostly depends on cold tolerance and duration of winter dormancy. A 2-year field study was conducted from May 2009 to July 2011 at the agricultural experimental farm of Padova University. The objective of this study was to assess the relationships occurring between spring green-up of seeded bermudagrasses and their nonstructural carbohydrates and crude protein (CP) content in stolons during late winter. The cultivars used were ‘Caribe’, ‘Mohawk’, ‘Princess-77’, ‘Sultan’, ‘SWI 1012’, and ‘Jackpot’. The plots were seeded in May 2009 and turf samples were collected in Mar. 2010 and 2011 for determination of stolons dry weight, diameter, and content of carbohydrates and CP. ‘Princess-77’ had lower content of starch in stolons compared with the other cultivars and was characterized by late spring green-up. The cultivars tested showed wide differences in stolons morphology (dry weight and diameter), whereas there were poor diversity for CP and water-soluble carbohydrates (WSC) in both years of research. Correlation analyses indicated a negative relationship between the days of the year necessary for spring green-up and stolons starch content and also between CP and starch. Moreover, there was a positive correlation between stolons starch and diameter, suggesting that spring green-up may be enhanced by selection of high starch-accumulating cultivars having coarse stolons.

Bermudagrass is becoming increasingly popular in the Mediterranean transition zone of Europe for establishing new sports and recreational turfgrasses. In these regions, the quality and winter hardiness of bermudagrass turf is influenced by the establishment. It has been demonstrated that an early establishment of bermudagrass results in a longer growing season with a greater stolon and rhizome production, which favors cold hardiness and a quicker green up after the first winter. Dormant seeding is reported to be beneficial for an early establishment. However, the response to early seeding depends on local environmental conditions. A field study was conducted in northeastern Italy during spring 2018 and 2019. Four bermudagrass cultivars (“Transcontinental”, “Jackpot”, “SR9554”, and “La Paloma”) were compared under three seeding times from March to May to evaluate whether early spring seeding allows anticipating the establishment of bermudagrass compared with late spring seeding which generally benefits of better temperatures for germination and growth. The number of days from seeding to the emergence and from seeding to the full establishment were determined, and the number of seedlings was counted in each plot. Late March seeding assured the earliest establishment. This result could be due to the quick lateral spreading of seedlings as the emergence occurred about 15 days later in the late March seeding compared with April and May seedings. Results also displayed that the speed of establishment was positively related to the number of emerged seedlings. “Transcontinental”, “Jackpot”, and “SR9554” performed similarly, whereas “Jackpot” showed a slower establishment.

De Luca et al., 2008) including species choice. Due to climate changes, warm-season species, and especially bermudagrass, are becoming popular in the transition zones of Europe (Macolino et al., 2016). However, only a few studies have investigated the effect of increased rainfall intensity on early-stage growth of warm-season turf species. Heavy or total plant submersion, or waterlogging when plants are not submerged but soil pores are saturated (Bailey-Serres et al., 2012; Striker, 2012). Waterlogging and, to a greater extent, submersion, can cause several visible symptoms on plants, especially when they are prolonged, such as reduced photosynthetic activity, abscission of leaves, chlorosis, lower growth of roots and stems (Batzli and Dawson, 1997). Flooding events can be extremely harmful to plants (Bailey-Serres et al., 2012), a decrease in oxygen diffusion rate (ODR), pH, and soil redox potential, and an accumulation of toxic com-uration (Parent et al., 2008; Voesenek et al., 2006). The oxyof oxygen to plant roots that can restrict seedling emergence (Chesworth, 2008; Neira et al., 2015). Studies by Letey et al. (1966) found that at ODR of 0.15-2 cm-1 roots growth of bermudagrass (Cynodon spp.) drastically reduced, even if