• Asian Journal of Turfgrass Science
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• v.5 no.1
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• pp.1-10
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• 1991

The purpose of the experiment was to determine the effect of nitrogen sources (urea, ammonium sulphate, ammonium nitrate) and potassium sources (potassium chloride, potassium sulphate) on the growth and quality of Zoysia japonica Steud. This experiment was conducted at Seoul City University turf field from 1988 to 1989. The results of this experiment were summarized as follows; 1. Urea and Ammonium sulphate resulted in superior clipping yield compared to ammonium nitrate. The growth of rhizome and stolon increased significantly with urea forms, but ammonium sulphate treated plots exhibited the highest the growth rate of root. 2. Ammonium sulphate showed best turf color rating while ammonium nitrate resulted in the poorest. Prolongation of the green period showed longer in ammonium sulphate and urea treated plots than ammoium nitrate. 3. Urea and ammonium sulphate exhibited superior visible quality and shoot density compared to ammonium nitrate. 4. The uptake of mineral nutrient showed the highest concentration with urea plots. Surface soil pH was allowed to become slightly acid with the ammonium sulphate and potassium sulphate treatments, while the application of N and K sources did not cause significant differences in mineral element content in soil.

• Asian Journal of Turfgrass Science
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• v.1 no.1
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• pp.30-36
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• 1987

In order to promote the germination of Korean lawn grass(Zoysia japonica Steud.) seeds a gravimetric seed selection with a mixed chemical solution and the germination promotion with KOH treatment were studied and following results were obtained. 1. When immersed into methanol(S.G., 0.7) 14 percent of immature seeds were precipitated. 2. With water (S.G., 1.0) 36.5 percent of mature seeds were submerged. 3. On a mixture of carbon tetrachloride (S.G., 1.6) and ethylether (S.G., 0.7) in a ratio of 4:6 the seed selection was most effective. 4. When treated with KOH solution the germination rate was 71.01 percent in contrast to 6.0 percent of germination without the treatment. 5. As for concentration of KQH solution, 15 percent depressed the germination (46.7 %) whereas above 20 % the germination rate was gradually increased (79.32 %) up to 40 percent of concentration where the concentration started to depress germination ratio (77.32 %). 6. Finally, in connection with the duration of KOH treatment, a time lapse of up to 20 minutes depressed the germinating ratio(70.02 %) and 30 minutes to 45 minutes increased this ratio to 94.52 percent. 60 minutes of treatment depressed the germination to 75.62 percent.

• 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.

• Asian Journal of Turfgrass Science
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• v.9 no.4
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• pp.275-284
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• 1995

In this investigation, the accumulation mineralization and annual cycle of organic P has been studied in grassland ecosysterns of a Z japonica grassland and a M sinensis grassland on Mt. Kwanak. The basic models of the accumulation and mineralization for ash components of a grass-litter have been presented as the equations (1), (2), and (3). The equations (7)~(10) for organic P are derived from these basic concepts. There was a highty significant relationship between organic matter and organic P. The estimates between organic matter and organic P correlated very high significance. The parameter factors k or k' of mineralization of organic P for the Z. japonica and M sinensis asslands were k=0.412 or k'=0.292 and k=0.224 or k'=0.183, respectively. The time required for a cycle to be completed from organic P to inorganic P of 50, 95 and 99 % are 3.9, 16.7 and 27.8 years in the Z. japonica grassland and 4.1, 17.7 and 29.4 years in the M sinensis grassland. The annual P cycle formulae for mineralization were based on the equations (5), (11) and (12). Annual yields of mineralization for organic P in the steady state grasslands of Z. japonica and M sinensis were 0.407 and 0.504g /$m^2$, respectively.

• 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.

• Asian Journal of Turfgrass Science
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• v.12 no.3
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• pp.237-248
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• 1998

The soil pH favored by Korean wild plants is 5.33~7.20, while naturalized invader species prefer soils of pH 3.95~6.48. The germination rate of Zoysia japonica was inhibited sharply, up to 60%, in extracts of naturalized plants of concentrations over 50%. Erigeron canadensis extract most strongly inhibited germination, while the Korean wild species, Cassia mimosoides var. nomame increased germination rates in concentrations of 30% and 50%. The seedling growth of Zoysia japonica in extracts of Korean wild species and naturalized species did not show differences, but was inhibited strongly, up to 60%, in the extract of Cassia mimosoides var. nomame concentration of over 15%. Analysis of the extract from Cassia mimosoides var. nomame identified procatechuic acid, $\rho$-hydroquinone, $\rho$-coumaric acid and ferulic acid at 254nm; and vanillic acid, hydroquinone, benzoic acid and cinnamic acid were discovered at 284nm. The seed germination and seedling growth of Zoysia japonica were investigated under different concentrations of phenolic compounds. Ferulic acid and vanillic acid were associated with an increased germination rate, while $\rho$-coumaric acid appeared to inhibit seedling growth.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.125-130
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• 2005

The effects of various pretreatment in Zoysia japonica are summarized as follows: Seeds that were treated for 7 days in $4^{circ}$C showed a little higher germination rates than those that were treated 3 days in $4^{circ}$C and for 1 day, 3 days in $-20^{circ}$C. Germination rates of the seeds that were soaked in NaOC1 showed higher germination rates than control group. BA 0.1 mg$\cdot$$L^{-1}$ treatment showed a little higher germination than GA3 0.1 mg$\cdot$$L^{-1}$, NAA 0.1 mg$\cdot$$L^{-1}$. Seed germination rates increased around $20^{circ}$C when the samples treated by BA and scarification. Leaf morphological didn't different between control and pretreatment groups.

• 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.

• Asian Journal of Turfgrass Science
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• v.4 no.2
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• pp.77-83
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• 1990

The effect of bio-fertilizer, which was manufactured poultry manure, on the fall performance of Korean lawngrass was determined on a clay loam soil. Plant length was characterized by increasing the amount of bio-fertilizer applied. This trend was also true in dry matter yield of tops during the experimental period from August 31 through October 30. Both tiller numbers and stolon length steadily increased with increasing amount of bio-fertilizer applied, and 40m/t application of bio-fertilizer was found to be most effective on both components. performance shown on November 5 was prominent for both green leaf and root weights when the increased amount of bio-fertilizer was applied. Korean lawngrass had three times as much green leaf weight with 40m/t application of bio-fertilizer as with other treatments. Several functions of increment of above- ground part components caused by increasing root weight, which is greatly affected by bio-fertilizer application, was discussed. Turf quality was much improved by applying bio-fertilizer, indicating that this fertilizer might play an improtant role in respect of soil structure, water retention etc.

• 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.