• Asian Journal of Turfgrass Science
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• v.22 no.1
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• pp.25-34
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• 2008

This study was conducted to determine the optimum dose ranges for a mutation breeding based on the observations of a seed germination and an early growth in turfgrasses. Three warm season (Zoysiagrass, Bermudagrass, and Seashore paspalum) and four cool season turfgrasses (Kentucky bluegrass, Tall fescue, Perennial ryegrass, and Creeping bentgrass) were used in this study. We investigated the percentage of a seed germination and a seedling growth after irradiating the turfgrass seeds with various doses of gamma-ray (50, 100, 150, 200, 250, 300, 400, and 500 Gy). After 24 h with a gamma irradiation, the seeds were sown on the wet filter paper in a petri dish and maintained for 3 weeks at 30$^{\circ}C$ for the warm season turfgrasses and at 25$^{\circ}C$ for the cool season turfgrasses. Data on a seed germination and a seedling growth with three replications were collected. The percentage of seed germination was decreased with an increase of the gamma-ray dose. Shoot and root growth, and the fresh weight were decreased significantly as the radiation dose was increased. A radiation dose indicating a 50% growth inhibition ($LD_{50}$) with a gamma irradiation was varied among those turfgrass species used, with the highest at about 500 Gy for bermudagrass and the lowest at 100Gy for tall fescue. The optimum dose for a gamma irradiation for a selection of turfgrass mutants was considered to be about 300, 150, 500, 150, 200, 100 and 200 Gy for zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, and creeping bentgrass, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.4
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• pp.221-226
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• 2006

This study was conducted to investigate the effect of tall type mixtures and turf type mixtures on dry matter yield, botanical composition and quality. The experimental design includes two mixture types : Tall type mixtures; orchardgrass (Potomac) 50+tall fescue (Fawn) 20+ Kentucky bluegrass (Kenblue) 10+red clover (Kenland) 20%) and turf type mixtures; Kentucky bluegrass(Newport) 60%+tall fescue (reboil Jr.) 20+perennial ryegrass (palmer II) 20%. The DM yield was higher obtained in tall type mixture than that of turf type mixture (p<0.05). In the chemical composition, Turf type mixture was higher in crude protein (CP) and dry matter digestibility (DMD), but lower in fibrous compound as NDF, ADF, cellulose and lignin than those of tall type mixture (p<0.05). The crude protein dry matter (CPDM) and digestible dry matter (DDM) yield was higher in tall type mixture than turf type mixture (p<0.05). In this experiment, nutritive value of turf type mixture was higher than that of tall type mixture, but CPDM and DDM yield of turf type mixture were lower than that of turf type mixture due to low dry matter yield. On the other hand, turf type mixture was obtained high feed value, and maintaining the various botanical composition on the 13 th cutting frequency condition. therefore, turf type mixture had a utilization possibility under grazing livestock as sheep and milk goats.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.2
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• pp.69-76
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• 2006

To optimize tissue culture responses for genetic transformation of Kentucky bluegrass, the effects of culture medium supplements on tissue culture responses were investigated with mature seeds of a cultivar 'Newport' as explant tissues. The optimal concentration of 2,4-D (2.4-dichloro phenoxy acetic acid) for the induction of embryogenic callus from mature seed was 3 mg/L. Plant regeneration frequency was 54% when embryogenic callus was cultured on the regeneration medium supplemented with 1 mg/L 2,4-D and 3 mg/L of BA (6-benzyladenine). Addition of 1 g/L of casein hydrolysate and 500 mg/L of L-proline improved frequencies of embryogenic callus induction and plant regeneration up to 60.8% and 58.3%, respectively. Regenerated plants were grown normally when shoots transplanted to the soil. A rapid and efficient plant regeneration system established in this study. We suggest that the results may be useful for molecular breeding of Kentucky bluegrass through genetic transformation.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.190-194
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• 2011

Potassium (K) is one of the essential nutrients for plants but is not a constituent of any plant compound. K is substances for activation of many enzymes and influences the process that the enzymes are involved in catalyzing. Although experimental results associated with the K effects with both benefits and no effects on turfgrass growth were reported, the limited research results of K effects on turfgrass among K sources are available in Korea. The objectives of the study was conducted to evaluate responses of Kentucky bluegrass (Poa pratensis L.) treated by fertilizer treatments with six K sources. There were six fertilizer treatments as K sources applied to Kentucky bluegrass which were potassium nitrate (13-0-44, PN), potassium chloride (0-0-60, PC), potassium sulfate (0-0-50, PS), polymer-coated potassium sulfate (0-0-45, PPS), potassium thiosulfate (0-0-25, PT), and potassium sulfate granulated with methylene urea (20-0-25, PSU). Potassium of $8g\;m^{-2}$ and N of $5g\;m^{-2}$ was applied 4 times giving a total 20 and $30g\;m^{-2}$, respectively. Although significant differences were found for turfgrass color, quality, chlorophyll index, and clipping dry weight, no consistent results among K sources were found during the one year study. Overall, K treatments didn't affect turfgrass growth in this study.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.3
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• pp.185-190
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• 2005

The objective of this experiment was to compare the dry matter intake, nutrients digestibility and nitrogen and energy utilization of herbages from mixtures types; conventional mixtures(orchardgrass 50+ tall fescue 20+perennial ryegrass 10+Kentucky bluegrass 10+white clover $10\%$), complex mixtures (orchardgrass 40+ tall fescue 20+perennial ryegrass 10+Kentucky bluegrass 10+redtop 10+alfalfa 5+red clover $5\%$) and simple mixtures(orchardgrass 80+red clover $20\%$) by Korean native goats. This experiment was conducted by total collection method in laboratory, 2000. The voluntary DM intake per body weight was slightly higher f3r complex mixtures (30.2g) than those of other mixtures. but there was no significant difference. The digestibility of dry matter and cellular constituents were slightly higher for complex mixtures than those of other mixtures (p<0.05), but NDF and ADF digestibilities did not differ among mixtures. The retained nitrogen percent (apparently biological value) was slightly higher fer complex mixtures $(55.1\%)$ than those of other mixtures, but there was no significant difference among mixtures. Apparently retained digestible energy was slightly higher for complex mixtures $(60.2\%)$ than those of other mixtures (p<0.05). Based on the results, the nitrogen and energy utilization of herbage by Korean native goats were slightly higher for complex mixtures than those of other mixtures.

• Journal of Life Science
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• v.18 no.8
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• pp.1096-1105
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• 2008

This study was carried out to identify the optimum condition for priming, as a series of experiments for the enhancement of germination percentage and germination synchronization in cool-season turfgrass seeds. The optimum priming conditions to maximize the germinability in both Kentucky bluegrass and Tall fescue was a 1 day treatment of 100 mM $K_3PO_4$ at $25^{\circ}C$. The seeds treated with the optimum priming condition enhanced the germinability compared to control, and shortened the time for germination with reduced $T_{50}$ and mean daily germination (MDG). However, as the concentration and treatment period of NaOH or KOH increased, significantly decrease in germination percentage was observed. Germination percentage in Creeping bentgrass and Bentgrass was below 10%, regardless of priming treatment. However, the priming treatment with 200 mM $KNO_3$ for three days improved the germination up to 6%, which was not a statistically significant level. The most effective priming period for Kentucky bluegrass and Tall fescue was one day treatment, but the germinability was suppressed as the treatment period was extended until six days. For priming chemical treatment, germinability was improved with the concentration of 100 mM, while it was reduced at higher concentrations of 200 mM and 300 mM.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.268-277
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• 2015

Organic fertilizer preparation was developed with organic materials to improve growth and qualities of cool-season turfgrass species. Organic fertilizer preparation were contained with essential macronutrient elements and organic matter for growth of cool season turfgrass. Four preparations of organic fertilizers were tested on creeping bentgrass (Agrostis palustris Huds) cultivar Penn-A1 and Kentucky bluegrass (Poa pratensis L.) mixed cultivars (Midnight 33%, Moonlight 33%, and Prosperity 33%) by one time application on fifty days after sowing. Two species of cool season turfgrasses were evaluated on turfgrass coverage, growth on NDVI (Normalized Difference Vegetation Index) and qualities from fall season to spring season in sod producing farm. It were found significantly difference found on turfgrass coverage, turf color, chlorophyll contents and growth increase on two species of cool season turfgrasses. Turfgrass coverage, chlorophyll content, turf color and growth increase of organic fertilizer preparation were significantly increased on creeping bentgrass cultivar and Kentucky bluegrass mixed cultivar for six time investigation in spring season. These results may indicate that the use of some preparation is beneficial for sod producing sod and turfgrass management.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.112-117
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• 2011

This research was conducted to determine the effect of the pre-treatment of mulberry charcoal on the salt tolerance response in Kentucky bluegrass 'Perfection'. As this results, 400 mM NaCl treatment reduced turf growth such a fresh and dry weight, and induced physiological damages like decreased chlorophyll content and increased electrolyte leakage. The pre-treatment of mulberry charcoal, however, mitigated those growth and physiological responses associated with NaCl stress, regardless of the concentrations of charcoal solution. Furthermore, it was observed that higher K ion concentration by mulberry charcoal pre-treatment reduced Na ion in shoot. This research suggests to be a possibility of planting turf grasses in reclaimed land or higher salt accumulated area using a mulberry charcoal treatment.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.399-401
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• 2006

• Asian Journal of Turfgrass Science
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• v.14 no.1
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• pp.241-250
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• 2000

In 1997, a new disease on creeping bentgrass and Kentucky bluegrass occurred in the green and fairway of a few golf courses in Korea. The disease spread gradually throughout the country and became a threat to turfgrass management. Symptoms of the disease consisted of small, circular, and sunken patches sized 3~5cm in diameter. The disease named as a dollar spot following its characteristic symptoms of circular blight and bleach on the green. The disease peaked two times in a year from April to June and from late August to October and white cottony mycelia of the causal fungus developed on diseased turfs in the early morning when the conditions were favored. A causal fungus was consistently isolated from the infected tufgrass and seven isolates originated from seven golf courses located in six provinces were selected for further study. The fungus produced abundant white aerial mycelia on PDA and turned to dark gray or light brown as it aged. Width of the mycelium was ca. $5~8\mu\textrm{m}$. While sclerotia were not readily formed on the medium, scattered small and dark colored stromata were developed on the surface. The fungus grew well on PDA between 5 to $30^{\circ}C$ and maximally around $25^{\circ}C$. Based on investigated mycological and cultural characteristics, the causal agent of dollar spot was identified as Sclerotinia homoeocarpa. The fungus showed strong pathogenicity to several turfs as creeping bentgrass, Kentucky bluegrass, perennial ryegrass, tall fescues, and zoysiagrass.