• Asian Journal of Turfgrass Science
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• v.22 no.1
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• pp.1-12
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• 2008

Remote sensing using multispectral radiometry may be a useful tool to detect drought stress in turf. The objective of this research was to investigate the correlation between drought stress and multispectral reflectance (MSR) from the turf canopy. St. Augustinegrass (Stenotaphrum secundatum[Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore paspalum Paspalum vaginatum Swartz.), 'Empire' zoysiagrass (Zoysia japonica Steud.), and 'Pensacola' bahiagrass (Paspalum notatumFlugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at 100%, 80%, 60%, or 40% of evapotranspiration (ET). Weekly evaluations included: a) shoot quality, leaf rolling, leaf firing b) soil moisture, chlorophyll content index; c) photosynthesis and d) multispectral reflectance. All the measurements were correlated with MSR data. Drought stress affected the infrared spectral region more than the visible spectral region. Reflectance sensitivity to water content of leaves was higher in the infrared spectral region than in the visible spectral region. Grasses irrigated at 100% and 80% of ET had no differences in normalized difference vegetation indices (NDVI), leaf area index (LAI), and stress indices. Grasses irrigated at 60% and 40% of ET had differences in NDVI, LAI, and stress indices. All measured wavelengths except 710nm were highly correlated (P < 0.0001) with turf visual quality, leaf firing, leaf rolling, soil moisture, chlorophyll content index, and photosynthesis. MSR could detect drought stress from the turf canopy.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.305-311
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• 2014

The cultivation area and use of genetically modified (GM) crops have been increased continuously over the world. Seed distribution and transgenes to environmental ecosystem is one of the most important factors in risk assessment and risk management of GM crop. Safe management for the development and commercialization of GM crops is required according to The Act on Transboundary Movements of Living Modified Organisms,etc (LMO Act) in Korea. This study was conducted to setup the environmental monitoring system of GM zoysiagrass (event JG21 and JG21-MS). The monitoring was performed in 4 GMO confined fields, Sungwhan, Ochang, Jeju University and Jeju Namwon. In the result of monitoring, we could not found any gene flow and distribution of GM zoysiagrass in the 3 fields, but one spill of JG21 was found in the Namwon field in 2012. These results suggest that continuous monitoring is necessary to detect the occurrence of GM zoysiagrass for preventing genetic contamination in natural environment.

• Asian Journal of Turfgrass Science
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• v.17 no.2_3
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• pp.75-80
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• 2003

Growth characteristics such as density(quality), covering speed, green period, disease resistance, heading existence(number of seeds) and other characteristics were examined for selection of superior lines among the 133 zoysiagrass lines collected in 2001. Six superior lines were selected and the results were summarized as follows. Superior line, J01067 was longest for green period among the 133 zoysiagrasses and stayed green until the beginning of November. Leaf width of J01106 and J01129 lines was very narrow as 1.5mm and 2mm, respectively and superior for density(quality), covering speed and disease resistance. J01122 line was selected for strongest disease resistance among the lines of Zoysia japonica. Leaf width of J01128 was 3.2mm showing midium type and similar to standard cultivar, Sunburst. This line also showed higher density and strong disease resistance like J01106 and J01129. Five growth characteristics for morphological classification of 133 zoysiagrass lines was used and divided into 3 cluster groups. Of 133 lines, 6 standard cultivars and 6 superior lines were classified as follows. First cluster group contained Belare, Meyer, Anyang-jungji, J01067, J01122, and second group contained S-94 and J01105, and third group contained Sunburst, Konhee, J01106, J01128 and J01129.

• Weed & Turfgrass Science
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• v.6 no.1
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• pp.40-54
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• 2017

The mound grave of Korean traditional funeral culture is a unique habitat which is a Zoysiagrass lawn being sustainable in proper management. We phytosociologically described an unusual Zoysiagrass vegetation with Gueldenstaedtia verna by the Zürich-Montpellier School's method and analyzed eco-floristic characteristics. A new association, Gueldenstaedtio-Zoysietum japonicae ass. nov. hoc loco, was identified and subdivided into festucetosum ovinae, typicum, and trifolietosum repensae. The subassociations were distinguished by the difference in species composition resulting from site accessibility and lawn management method. The association was assigned as not only a regional but also a locally-limited vegetation type, which distributes on a particular microhabitat with strong continentality in the Daegu regional subdistrict of Bioclimatological division. The Zoysiagrass vegetation of Korea was considered as a continental type apparently different from the oceanic type of Zoysion japonicae (Miscanthetea sinensis, Caricetalia nervatae). Mound graves in Korea should be acknowledged as a meaningful habitat for the in-situ conservation of biodiversity and phytocoenosen, despite being a secondary grassland of Gueldenstaedtio-Zoysietum japonicae.

• Asian Journal of Turfgrass Science
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• v.16 no.2
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• pp.65-73
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• 2002

Studies were conducted to determine the effect of undersoil heating on growth and quality of turfgrasses including Kentucky bluegrass (Poa pratensis L.‘Nuglade’), perennial ryegrass (Lolium perenne L.‘Accent’), tall fescue (Festuca arundinacea Schreb.‘Pixie’), and Korean lawngrass (Zoysia japonica Steud.) in simulated athletic field during winter season in Korea. Mineral contents in clippings of turfgrasses grown at different soil mixtures and temperatures were also analyzed. Undersoil heating (approximately 20$\pm$2$^{\circ}C$) was effective in protecting turfgrasses except Korean lawngrass from freezing injury and discoloration of shoots due to extremely cold temperatures during midwinter. Among turfgrasses grown at undersoil heating zone, tall fescue and perennial ryegrass showed the highest clipping weights and chlorophyll contents, respectively. However, anthocyanin contents of shoots were higher in Kentucky bluegrass. There was little or no difference in clipping weights, chlorophyll contents, anthocyanin contents and greenness of shoots between turfgrasses grown at two soil mixtures composed of 80% sand＋10% peat moss＋10% soil (v/v/v) and 80% sand＋20% pea moss (v/v). Contents of mineral K, Ca and Mg in clippings of cool-season turfgrasses were comparatively higher in a soil mixture composed of 80% sand＋10% peat moss＋10% soil, but little difference in contents of N and P was observed between two soil treatments. Results indicated that undersoil heating can improve quality of turf surface by thawing soil, melting snow, and maintaining shoot growth and greenness of turfgrasses in sports field during winter season.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.492-500
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• 2015

Our previous report demonstrated successful isolation of soil-borne bacteria that suppressed the potential of Rhizoctonia solani AG2-2 (IV) causing turfgrass large patch disease when applied to Korean lawngrass (Zoysia japonica). The current study aimed to uncover the mechanisms of this antagonism of Rhizoctonia solani and to define culture conditions for the isolated microbes. We found that two Bacillus isolates, I-009 and FRIN-001-1 strains, produced cellulase and siderophore, but not chitinase, while the Pseudomonas YPIN-022 strain was found to release only siderophore, implying that three antagonistic bacteria commonly interrupt Fe uptake by the large patch pathogen. The I-009 and FRIN-001-1 isolates grew best at 35 and $30^{\circ}C$ in growth medium of pH 5 to 8 for 32 and 28 h, respectively, while optimum growth for the YPIN-022 strain was found at $35^{\circ}C$ at pH 5 to 9 for 24 h. Good growth of I-009 and YPIN-022 over 24 h was obtained in M9 minimal medium supplemented with 1% sucrose, 0.5% yeast extract and 0.1% potassium chloride. FRIN-001-1 grew well in M9 medium with 1% mannitol, 0.5% yeast extract and 0.1% potassium phosphate dibasic.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.71-75
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• 2015

Playground is frequently used for physical and sports activity by students as well as by common people, which is constructed with various cover materials on the ground. This research surveyed the surface temperature in Kyungpook National University Sangju campus playground which is covered with various cover materials [bare field, zoysiagrass (Zoysia japonica) turf field, urethane track, concrete field, epoxy field and artificial turf field] in Sangju, Gyeongsangbukdo, Korea. Temperature was measured 4 times per day at 09:00, 12:00, 15:00, and 18:00 from May to October 2014 in surface and 1 m height above the ground. Surface temperature was different, depending on cover materials and survey time. Bare field and zoysiagrass turf field was lower surface temperature than other sites. Higher surface temperature site was different depending on survey time. Urethane track and artificial turf field was hotter than other sites at 12 and 15 hours, however concrete and epoxy field was hot at 18 hours. One meter above ground temperature was the highest in artificial turf field except at 18 hours. So natural turf, zoysiagrass playground will increase the athletic performance by reduce the surface and above ground temperature.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.165-169
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• 2016

To establish the soil management system for the efficient sod production, survey on the growth of zoysiagrass by different soil managements was conducted in repeated cultivation field with regard to soil physical properties. Soils were subjected to four types of management methods, which include (1) rolling (2) topdressing (3) topdressing + rolling (4) topdressing + tillage + rolling. The topdressing + tillage + rolling treatment significantly ameliorated soil physical properties such as bulk density, porosity and solid phase as compared to rolling and topdressing + rolling treatments, and was not significantly different from the topdressing treatment. Further growth and density of zoysiagrass except for the root dry weight in topdressing + tillage + rolling treatment were significantly higher than that only in rolling treatment. Topdressing + tillage + rolling treatment significantly increased the number of shoot as compared to the other treatments. Therefore, combined topdressing and tillage soil management practice should be conducted for the production of zoysiagrass in repeated cultivation field.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.648-655
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• 2010

This study is the first comprehensive report on the molecular cloning, structural characterization, sequence comparison between wild and mutant types, copy number in the genome, expression features and activities of a gene encoding 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in Korean lawn grass ($Zoysia$ $japonica$). The full length cDNA of the EPSPS from Korean lawn grass ($zj$EPSPS) obtained from a 3' and 5' RACE method was 1540 bp, containing a 1176 bp ORF, a 144 bp leader sequence (5' UTR) and a 220 bp 3' UTR, which was eventually decoded 391 amino acid residues with a molecular mass of 41.74 kDa. The Southern blot detection of the $zj$EPSPS showed that the gene exists as a single copy in the Korean lawn grass genome. Sequence comparison of the $zj$EPSPS gene demonstrated that the glyphosate-tolerant mutant (GT) having a Pro-53 to Ser substitution in the gene seems to have a preferred binding activity of the enzyme to phosphoenol pyruvate(PEP) over glyphosate, which allows the continuous synthesis of aromatic amino acids in the shikimate pathway. From the Northern blotting analysis, the $zj$EPSPS was found to be highly expressed, with continuous increase until 36 hours after 0.5% glyphosate treatment in both wild and mutant samples, but 1.5-fold higher EPSP synthase activity was observed in the tolerant mutant when exposed to the glyphosate treatment. The molecular information of the $zj$EPSPS gene obtained from this study needs to be further dissected to be more effectively applied to the development of gene-specific DNA markers and zoysiagrass cultivars; nevertheless, the glyphosate-tolerant mutant having the featured $zj$EPSPS gene can be provided to turfgrass managers for weed problems with timely adoptable management options.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.342-353
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• 2016

This study was initiated to evaluate green color retention under three different soil systems. Several turfgrasses were evaluated in multi-layer, USGA, and mono-layer systems. Turfgrass entries were comprised of three cultivars of Korean lawngrass (Zoysia japonica Steud.) as warm-season grass (WSG) and three blends and three mixtures of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.) as cool-season grass (CSG). Significant differences were observed in visual turf color and green color retention among soil systems and turfgrasses. Both the multi-layer and USGA systems were highly associated with better color ratings and longer color retention, as compared with the mono-layer system. Seasonal variation of visual turf color greatly occurred from late December to early spring. CSG exhibited longer color retention than did WSG. The latter maintained green color for approximately 6 months, regardless of the soil system. Spring green-up of Korean lawngrass occurred from early to middle May, while it underwent discoloration from late October to early November. Among the CSGs green-up occurred between early March and early April and leaf color was maintained until middle December to early February. Therefore, the CSGs were green for 8.5 to 11 months, depending on turfgrass and soil system. The mean period of green color duration across all soil systems was approximately 10-11, 9-10 and 8.5-9.0 months for PR, KB and TF, respectively. As for the CSG mixtures, the greater the proportion of PR, the longer the green color retention, while the higher the proportion of TF, the shorter the color retention. There was greater variation in green color duration among the CSGs than the WSGs. Across soil systems, color retention differences of 2 to 6 days were observed for the Korean lawngrass, but 7 to 36 days for the CSGs. These results demonstrate that green color retention varied greatly according to soil systems and also among turfgrasses. Selections of turfgrass and soil system should be made using a concept-oriented approach, when establishing garden, park, soccer field, golf course and other sports field. Information obtained in this study can be used to select soil systems and turfgrasses based on the expected degree of leaf color retention.