• Asian Journal of Turfgrass Science
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• v.9 no.3
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• pp.207-212
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• 1995

This experiment was conducted to investigate the effect of the nitrogen fertilization levels on the content of $NH_4^+$-N in soil of 'Suffolk' Kentucky bluegrass and zoysiagrass. The results obtained are summarized as follows : 1.According to the nitrogen fertilization levels, the content of $NH_4^+$-N in soil of Kentucky blue-grass and zoysiagrass was not significantly different. The content of $NH_4^+$-N in soil of Kentucky bluegrass and zoysiagrass was highest in June and December and lowest in March and September. 2.The content of $NH_3^-$-N in soil was increased by increasing the nitrogen fertilization levels in both Kentucky bluegrass and zoysiagrass. However, the deeper the depth of soil the less the content of $NO_3^-$-N in soil. In 40~60cm soil depth, the content of $NO_3^-$-N in soil was lower than 10ppm in average. Even in June, which was the highest month of the content of $NO_3^-$-N in soil, the content of $NO_3^-$-N in soil was not overpassed the degree of 20ppm.

• Weed & Turfgrass Science
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• v.6 no.4
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• pp.283-291
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• 2017

Zoysiagrass has been used in Korea as a native grass. Informations on distributions, classifications, breeding efforts and outputs, current production and uses of zoysiagrasses in Korea are summarized. During past a few decades, collection of naturally growing zoysiagrass ecotypes has been continued, followed by evaluation, selection and cross-pollination. Classification efforts using important morphological, biochemical traits and DNA polymorphisms resulted in the several suggestions of grouping zoysiagrass species and varieties. Zoysia japonica consistently form separate group, while Zoysia sinica and Zoysia macrostackya have been separately or inter-mixed. Z. matrella with some variations frequently grouped separately but with some similarity with Z. tenuifolia, which was recently renamed as Z. pacifica. Hybrid types of zoysiagrasses were frequently found in Korea. New varieties such as 'Kunhee' and 'Green Ever' etc. were bred by ecotype selections, while 'Senock', 'Semil', 'Millock' were bred through pollination. Molecular approaches were also used to introduce beneficial genes into zoysiagrasses with no practical outputs by legal regulations. Currently popular varieties are inter-specific hybrid types such as 'Anyang' and other local zoysiagrasses as well as common zoysiagrass (Zoysia japonica) Production area in Korea was estimated as 2,947 ha with increasing problems of mixed or contaminated species and varieties.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.285-292
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• 2009

Zoysiagrass (Zoysia japonica) is one of the important turfgrass species. Extending green period of zoysiagrass via delaying leaf senescence will make this species have more potential in the turfgrass industry. In this study, we found that zoysiagrass seedlings treated with $GA_3$ could delay the leaf senescence induced by darkness. To study expression of genes responsive to staying green in zoysiagrass, suppression subtractive hybridization (SSH) was used to identify differentially expressed genes between non-$non-GA_3-treated$ and $GA_3-treated$ seedlings subjected to darkness. A total of 307 ESTs were generated, of which 226 ESTs clustered into 54 contigs and 81 were singlets. Differentially expressed genes selected by subtractions were classified into six categories according to their putative functions generated by BLAST analysis. Expression of five selected genes, Met, SAM, V-ATPase, Cry (Cryptochrome gene), and An (diphthine synthase gene) were examined by RT-PCR and Real-time PCR. Both RT-PCR and Real-time PCR results demonstrated that the differential expressions of these genes were attributable to delaying senescence by exogenously applied gibberellic acid. This is the first genome-wide study of senescence in a species of turfgrass.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.3
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• pp.107-113
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• 2003

Ecological control can contribute to the sustainibility of vegetation management systems by reducing the input currently derived from non-renewable fossil energy sources. The use of turfgrass mixtures is an important tool in turf management. Turfgrass mixtures of two or more compatible and adapted species provide improved tolerance to pest and environmental stress, more so than monostands. The objectives of this study were to evaluated turf insects, pests and zoysia large patch control by turgrass mixtures. In April 2001 and 2002, plots were inoculated with 50g of Rhizoctonia solani AG2-2LP inoculum. Inoculum were treated within a 29cm diamater circle at Zoysia japonica, Zoysia japonica, Poa pratenis, or Festuca arundinacea mixtures. After four weeks, disease severity in each plot was determined. plot area visual ratings were assessed visually on a linera 0 to 100%. In August 2001 and October 2002, turf insects and pests in each plot were investigated in 10cm deep soil cores with 8cm diameters using hole cut. Zoysia large patch affected zoysiagrass monostands more severly than zoysiagrass and cool-season turfgrasses mixtures. It was suggested that the barrier effect of cool-season turfgrass suppressed zoysia large patch in the mixture of zoysiagrass and cool-season turfgrasses. Also, warm-season and cool-season turfgrasses mixtures suppressed insect populations more efficiently than warm-season turfgrass monostands.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.383-389
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• 2015

The use of zoysiagrass (Zoysia japonica Steud.) in the transition zone is limited because of a lack of cold hardiness although zoysiagrass has many advantages compared to other warm-season and cool-season grasses. Late-fall N fertilization is often applied for darker green color of turfgrass in early spring and more extensive root growth without rapid top growth. The objective of the study was to evaluate the effects of late fall N application and turf cover for zoysiagrass spring green-up. Clear polyvinyl chloride (PVC) film was used for turf cover. The amount of N applied were 5 and $10g\;N\;m^{-2}$ for the low and high N rate treatments, respectively. Covered zoysiagrass had greater turfgrass color and quality in early spring than non-covered zoysiagrass. The high N rate had 0.6 to 2.3 greater turfgrass quality than the low N rate on 7 of 9 rating dates. Slow-release N as late fall fertilization is more effective for turfgrass color and quality than fast-release N in spring. Turf cover could reduce the period of yellow zoysiagrass, and the earlier time of spring green-up could be advanced by increasing turfgrass quality and growth of zoysiagrass.

• Asian Journal of Turfgrass Science
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• v.18 no.4
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• pp.211-219
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• 2004

Transgenic zoysiagrass (Zoysia japonica cv. Zenith) plants have been obtained by particle bombardment of embryogenic callus with the plasmid pSMABuba, which contains hygromycin resistance (hpt) and bialaphos resistance (bar) genes. Parameters on DNA delivery efficiency of the particle bombardment were partially optimized using transient expression assay of a chimeric $\beta-glucuronidase$(gusA) gene driven by the CaMV 35S promoter. Stably transfarmed zoysiagrass plants were recovered with a selection scheme using hygromycin. Transgenic zoysiagrass plants were confirmed by PCR analysis with specific primer for bar gene. Expression of the transgene in transformed zoysiagrass plants was demonstrated by Reverse transcriptase (RT)-PCR analysis. All the tested transgenic plants showed herbicide BastaR resistance at the field application rate of $0.1\%-0.3\%$.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.17-22
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• 2016

Yellow tuft symptoms of a dense cluster on zoysiagrass (Zoysia japonica Steud.) occurred extensively at cultivated fields of zoysiagrass sods in Jangsung. The dense cluster of zoysiagrass showed significant morphological changes such as the tufts of shortening of internodes. The disease symptom was spread on a large scale throughout stolon nodes with multiple short leaves and it thrives in broom-like shaped clusters, exhibiting light green or yellow color on their leaves. The dense cluster of zoysiagrass had approximately 5.8 times more leaves on each node of its stolon then healthy zoysiagrass. Also, these zoysiagrass had poorly developed root and stolon caused by the tufts of a dense cluster of shoots. The dense cluster of zoysiagrass were collected for the putative causal agent incubation and upon close observation, it was found that the sporangia took the shape of a lemon, each sporangium was pointed at the end of its axis and was measured to be $60{\sim}96{\times}42{\sim}51{\mu}m$. These findings were analogous to the mycological characteristics of sporangia formed by the pathogen Sclerophthora macrospora. The symptoms of yellow tuft were prevalent in spring and autumn. Therefore, this study aims to present fundamental data in relation to yellow tuft on zoysiagrass in Korea.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.35-43
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• 2012

These studies were carried out to ascertain the effects of paraffin oil on prolongation of the green leaf color period in Zoysiagrass. Fifty-fold diluted 98% paraffin oil treatment obtained the lowest reduction rate of green color. In early October we sprayed 50-fold, 100-fold and 200-fold diluted 98% paraffin oil in a Zoysia japonica field in Hapcheon of Gyeongnam and Sangju of Gyeongbuk and in a Z. matrella field in Gumjung of Busan and Anseong of Gyeonggii. Leaf color maintained for 60 days after treatment in Zoysia japonica. Leaf color remained for 60 days after treatment in Anseong, Hapcheon and Sangju when treated in the mid-October. Chlorophyll content was higher in paraffin oil treatment areas than in control areas in early October. Weight reduction rate was lower in the paraffin oil treated than in untreated leaves of Zoysiagrass when sprayed in Gumjung and Anseong in early October and mid-October, respectively. The chlorophyll content in leaves of Z. japonica was increased by increasing the spray volume of paraffin oil in the same dose treated in Lexington, Kentucky, USA. Paraffin oil can be used to prolongate of Zoysiagrass leaf color.

• Asian Journal of Turfgrass Science
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• v.11 no.4
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• pp.321-326
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• 1997

A high seed yield '232' was evaluated for morphological characteristics and tissue culture re-sponse. The effect of mowing and urea application on coverage in '232' was also studied and the results were as follows ;1.'232' produced high seed yield than any other lines, but its other characteristics such as coverage, establishment rate, stolon length, stolon number and colour change were not good. 2.Callus induction of '232'(52.9%) was relatively high, and higher than that of Z. sinica(49.0%). However, embryogenic callus formation of '232' was not as good as that of Z. japonica and Z. sinica. 3.Coverage of '232' was very much enhanced by mowing on July 18, but not at all by mowing on May 29 and September 4. 4.Urea application did not increase the coverage in '232',Therefore, it can be used as a breeding material rather than direct use.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.1
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• pp.29-36
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• 2004

In an effort to optimize tissue culture responses of zoysiagrass(Zoysia japonica Steud.) for genetic transformation, factors affecting callus induction and plant regeneration were investigated. MS medium containing 3 mg/L 2,4-D was optimal for embryogenic callus induction from mature seed. The plant regeneration frequency of 73.3% was observed when embryogenic calli induced in this medium were transferred to N6 medium supplemented with 0.1 mg/L 2,4-D and 5 mg/L BA. Among several basic media, MS and N6 medium were optimal for callus induction and plant regeneration, respectively. Regenerated plants were grown normally when shoots transplanted to the soil. A rapid and efficient plant regeneration system established in this study will be useful for molecular breeding of turfgrass through genetic transformation.