Effects of Winter Overseeding and Three-demensional Clipping Management on Warm-season Turfgrasses

Perennial ryegrass (Lolium perenne L.) is commonly overseeded into hybrid bermudagrass [Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt Davy] turfs during autumn in the southern United States. Overseeding can provide a green, actively-growing turf throughout the winter dormancy period. Improved persistence of perennial ryegrass cultivars has increased management inputs during the spring transition period. Lower input turf systems that provide acceptable winter overseeding quality are preferred, and research aimed at evaluating alternative overseeding species are warranted. Grooming reel attachments allowing for threedimensional clipping management (3DCM) have become increasingly used by turf managers for reducing grain and thatch, but scientific information on best management practices and canopy effects of 3DCM-grooming are lacking. A field study was conducted at the Texas A&M Turfgrass Field Laboratory in College Station, TX (30.6191 degrees N, 96.3576 degrees W), to investigate the effects of overseeding using annual (Lolium multiflorum Lam.) and perennial ryegrasses on 3DCM-groomed and non-groomed fairway turfs of 'Tifway' hybrid bermudagrass, zoysiagrass [Zoysia matrella (L.) Merr. 'Cavalier'], and seashore paspalum (Paspalum vaginatum Sw. 'Sea Isle 1'). The study was arranged as a randomized complete block split-split-plot with three replications. Species whole main plots were split into three grooming intervals, which were further split into four overseeding treatments. Data were collected assessing visual turf quality, visual turf cover, leaf area index, clipping yield, shoot density, and biomass partitioning. Results indicate annual ryegrass alone and an annual/perennial ryegrass overseeding mix provided acceptable turf quality, but did not improve turf recovery over perennial ryegrass alone in 'Tifway' or 'Sea Isle 1' turfs. In 'Cavalier' turfs, summer quality was affected by overseeding treatment as follows: control > annual > annual/perennial > perennial. The overseeding tolerance of the warm-season turfgrasses was as follows: 'Sea Isle 1' > 'Tifway' > 'Cavalier'. Differences in canopy architecture of warm-season turfgrasses were related to the overseeding tolerance of each species and used to explain plant competition during the spring transition period. Grooming by 3DCM improved late-season turf quality and reduced scalping in 'Tifway'. Overseeding establishment and canopy architecture were not affected by 3DCM

Diurnal patterns in light quality and photosynthesis on creeping bentgrass under tree shade

Lew Wentz FoundationHorticulture and Landscape Architectur

Genetic and QTL mapping in African bermudagrass

Cynodon transvaalensis Burtt-Davy is frequently used to cross with C. dactylon Pers. in the creation of F1 hybrid cultivars that are some of the most widely used in the worldwide turf industry. However, molecular resource development in this species is limited. Accordingly, the objectives of this study were to construct a high-density genetic map, and to identify genomic regions associated with establishment rate. In this study, we constructed the first high-density linkage map for African bermudagrass using a genotyping by sequencing approach based on 109 S1 progenies. A total of 1,246 single nucleotide polymorphisms and 32 simple sequence repeat markers were integrated in the linkage map. The total length of nine linkage groups was 882.3 cM, with an average distance of 0.69 cM per interval. Four genomic regions were identified to be associated with sod establishment rate. The results provide important genetic resources towards understanding the genome as well as marker-assisted selection for improving the establishment rate in bermudagrass breeding.Horticulture and Landscape ArchitecturePlant and Soil Science

Persistence and Surface Playability of Nine Bermudagrass Cultivars under Simulated Fall Traffic

Traffic injury caused by foot- or athlete-surface interaction is one of the most critical problems athletic field managers face in maintaining the surface playability and aesthetic quality of athletic fields. Bermudagrass (Cynodon spp.) is the most widely used turfgrass species on athletic fields in the transitional climatic zone. A 2-year field study was conducted to evaluate nine bermudagrass cultivars for their persistence and surface playability under simulated fall cleat traffic. The experiment was conducted in Stillwater, OK, on a natural loam soil. Treatments were arranged as a split-block design with three replications. Traffic was applied for 6 weeks in Fall 2019 and 2020 using a Baldree traffic simulator, which generated 10 traffic events per week; each traffic event resulted in 678 cleat marks/m2. ‘Bimini’ was generally found to be the most persistent grass under traffic for aesthetic properties, and ‘Astro’ and ‘Tifway’ were the least persistent. Surface playability was affected by simulated traffic stress as shear strength (SS) declined and surface hardness (SH) increased, over time. ‘Bimini’ had greater SS than ‘Astro’ and ‘OKC1131’ (Tahoma 31®) by 1.9 and 1.4 N·m, respectively. SS of ‘DT-1’ (TifTuf®) and Tahoma 31 and SH of ‘OKC1134’ (NorthBridge®) were least affected by simulated traffic stress. Overall, surface playability characteristics of NorthBridge, ‘Bimini’, ‘OKC1119’ (Latitude 36®), TifTuf, Tahoma 31, and ‘Riley Riley’s Super Sport’ (Celebration®) were least affected by traffic. Findings illustrate bermudagrass cultivars can vary in visual persistence and surface playability

Effect of antecedent drought stress on spring green‐up in turf‐type bermudagrasses

Abstract Winterkill is a major concern for turf‐type bermudagrasses [Cynodon dactylon (L.) Pers. and C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] when cultivated in the US transition zone and frequently occurring drought conditions challenge bermudagrass management. Therefore, developing new bermudagrasses with both drought resistance and winter survivability are needed for the future sustainability of the turfgrass industry in the transition zone. How these two traits interact within bermudagrass populations is not widely reported. Accordingly, the objectives of this study were to estimate reliability for spring green‐up (SG) (as an indicator of winter survivability) and drought response in turf‐type bermudagrasses. A total of 77 experimental genotypes and 7 cultivars were planted in a randomized complete block design with 3 replications over 2 years in Goodwell, OK, USA. Substantial genetic variations were found for drought response and SG parameters when analyzed by year, but variations for SG parameters and leaf firing were not significant when analyzed across years. The reliability estimates for drought response ranged from low to moderate (i2 = 0.24–0.61), whereas the subsequent estimates for SG were low (i2 = 0.13–0.33), suggesting poor reliability. The low‐to‐moderate reliability values in SG were likely due to antecedent drought injuries, indicating that winter survivability and drought resistance may need to be evaluated in separate trials

A new internet tool to report peritoneal malignancy extent. PeRitOneal MalIgnancy Stage Evaluation (PROMISE) application

International audienceBased on the importance of assessing the true extent of peritoneal disease, PeRitOneal MalIgnancy Stage Evaluation (PROMISE) internet application (www.e-promise.org) has been developed to facilitate tabulation and automatically calculate surgically validated peritoneal cancer index (PCI), and other surgically validated scores as Gilly score, simplified peritoneal cancer index (SPCI), Fagotti and Fagotti-modified scores. This application offers computer-assistance to produce simple, quick but precise and standardized pre, intra and postoperative reports of the extent of peritoneal metastases and may help specialized and non-specialized institutions in their current practice but also facilitate research and multicentre studies on peritoneal surface malignancies

Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

International audienceThe aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed