Development of Paspalum accession plugs for turfgrass establishment

The selection of a genotype for lawn use must consider the plant survival rate and its soil covering ability, which is directly influenced by the growth of stolons and rhizomes. This study aimed to evaluate the growth and development of Paspalum accession plugs for turfgrass establishment. Plugs of six prostrate growth accessions of Paspalum lepton (PL 01), P. notatum (from PN 01 to PN 06) and Zoysia japonica (ZJ 01), which was used as the control treatment, were planted adding up to 7 treatments. At 63 days after planting, the survival rate, the number of shoots, the expansion capacity, plant height and soil coverage rate were evaluated. Moreover, at 72 days after planting, fresh and dry leaf, root, rhizome and/or stolon biomass, as well as root length were evaluated. Plugs of PL 01 presented the highest values regarding the number of shoots, the expansion capacity, soil coverage and the development of the root system with the largest biomass production. PL 01 and PN 05 along with ZJ 01 presented a high soil coverage rate and all the P. notatum (PN) accessions together with ZJ 01 maintained a lower plant height, but with a length root system higher than the control treatment ZJ 01. The P. lepton (PL 01) and P. notatum (PN 05) accessions can be recommended for turfgrass establishment using plug propagation methods.

Selection of Brazilian native turfgrass accessions for establishment by sprigs

Researches with Brazilian native species of Axonopus and Paspalum genus have indicated their lawn-use. Thus, this research aimed to evaluate the use of sprigs, which are rhizomes and/or stolons fragments of plants without substrate and with reduced aerial part, as a propagation method for turfgrass establishment. Two experiments were developed. Experiment 1: turfgrass sods (1026 cm²) from Axonopus parodii (AP 01), Paspalum lepton (PL 01) and P. notatum (PN 01 to PN 06) accessions, were fragmented in a straw crushing machine in order to obtain the sprigs. After cleaning the substrate and organic residues from the sprigs, the following variables were analyzed: total number of sprigs; minimum, maximum and average length of the sprigs; standard deviation; number of sprigs shorter than 2 cm, from 2 to 4 cm, and from 4 to 6 cm long. Experiment 2: sprigs from three different length classes were planted and evaluated at 63 days after planting. The commercial variety Zoysia japonica (ZJ 01) was used as a control treatment. The following characters were analyzed: the survival rate of the sprigs, the number of shoots, expansion, soil coverage rate, dry biomass of aerial part, and dry biomass of the roots. Correlations were made among the data obtained. Higher yields were obtained for sprigs shorter than 2 cm and from 2 to 4 cm. All accessions presented better development when established with sprigs longer than 2 cm. The Paspalum notatum accessions PN 01, PN 02, PN 03 and PN 05 could be selected for turfgrass establishment by sprigs propagation.

Effects of Sub-Optimal Temperatures on Seed Germination of Three Warm-Season Turfgrasses with Perspectives of Cultivation in Transition Zone

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.

APPLICATION OF MYCORRHIZAL FUNGI IN LANDSCAPE TURFGRASS ESTABLISHMENT UNDER ARID AND SEMIARID ENVIRONMENTS

Turf grasses are considered an integral part of landscape ecological systemsworldwide which provide functional, recreational and aesthetic benefits to societyand the environment. In arid and semiarid regions (e.g., Mediterranean region),turf grass is usually grown under harsh and unfavorable growing conditions withlow rainfall and high rates of evapotranspiration as well as in soils with nutrientdeficiencies. Hence, growing turf grass in these regions becomes dependent onapplication of high levels of fertilizers as well as on excessive use of irrigationwater, resulting in an environmental pollution. Therefore, it is important that turfgrass plantations are managed in a sustainable way to reduce the impact of turfgrass cultivation on ecosystems while maintaining healthy and productive turfthrough using such practices as mycorrhizal fungi technology. The application ofmycorrhizal fungi technology is an option that can benefit both agronomic planthealth and ecosystems. Mycorrhizae confer numerous benefits to host plantsincluding improved plant growth, mineral nutrition, water uptake, tolerance todiseases and stresses such as drought and salinity. The aims of this paper were toreview how mycorrhizal fungi might play a role in enhancing landscape turfestablishment and productivity in arid and semiarid regions and to evaluate theeffectiveness of application of commercial mycorrhizal inoculum to enhance plantgrowth and survival under field conditions. Field experiment was conducted tostudy the effects of arbuscular mycorrhiza (AM) fungi inoculation on water useefficiency and establishment of a landscape turf. The results showed that turf grassinoculated with AM fungi used water more efficiently, established lawn morequickly and had more biomass than uninoculated turf grass. The conclusions of thispaper indicated the potential of mycorrhiza inoculation in improving the fastestablishment of turf landscape plants under arid and semiarid environments.

Low-dose Application of Nonionic Alkyl Terminated Block Copolymer Surfactant Enhances Turfgrass Seed Germination and Plant Growth

Rapid seed germination and vigorous seedling growth are desired when establishing turfgrass lawns from seed. Low-dose concentrations of nonionic, block copolymer surfactants can have a direct effect on plant physiological functions and growth. The objectives were to determine if a low-dose application of a nonionic alkyl ended block copolymer surfactant applied directly to the seed, within a film coating, would 1) influence speed, synchrony, and final germination percentage (FGP), and 2) enhance seedling emergence and the speed of turfgrass establishment under deficit irrigation. Tests were performed with tall fescue (Schedonorus arundinaceus) and perennial ryegrass (Lolium perenne). Surfactant was applied directly to the seed using a rotary seedcoater at 0.1% by weight of seed. In the first experiment, germination was compared between seeds with a surfactant film coating (SFC) and untreated seeds in growth chambers at three different constant temperatures (10, 20, and 30 °C). For both species, the SFC decreased the time for seed germination, and improved germination synchrony, with the greatest treatment response at 10 and 30 °C compared with untreated seed. Application of a SFC did not influence FGP. In the second experiment, untreated and treated seed were compared in a grow-room study, with pots watered weekly to 70% of field capacity (FC). Perennial ryegrass density, cover, and aboveground biomass from the SFC were ≈47%, 48%, and 46% greater than untreated seed, respectively. Tall fescue density, cover, and aboveground biomass from the SFC seeds were ≈22%, 23%, and 28% greater than untreated seed, respectively. Overall these studies demonstrate that SFC can promote seed germination and also enhance turfgrass establishment under deficit irrigation.