• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.9-15
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• 2010

During 2008~2009 winter season, yellow patch and gray snow mold occurred on turfgrass plants in golf courses in Kangwon and Jeonbuk provinces, respectively. The fungi associated with the diseases were identified as Rhizoctonia cerealis Van der Hoeven and Typhlua incarnata Lasch ex Fr., based on the morphological characteristics of hyphae and sclerotia. R. cerealis and T. incarnata were pathogenic to most turfgrass and crop species tested. R. cerealis infected crown, stem and leaf tissue of the host plants, and the symptom was light yellow circular patch. Individual infected leaf near the margin of patch developed red color first and finally turn brown. The symptoms caused by gray snow mold pathogen are water-soaked spots, and became a watery soft rot. Infection parts became yellow and then turned brown followed by death of the whole plant. White mycelia were developed on higher petioles, leaves, and on soil where these plant parts lay, and black sclerotia of variable size and shape formed in the mycelial mass. All isolates tested were pathogenic on most turfgrass and crop plants, and significantly different in aggressiveness. Disease severity increased with longer snow cover days on target plants, suggesting that disease severity was expressed over snow cover days. There were significant differences in disease severity among the graminious species, and among cultivars within each species, indicating varying levels of susceptibility to R. cerealis and T. incarnata.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.321-328
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• 1987

In order to examine the factors affecting herbicidal injury of pepper, crop injury and growth response of 2 red pepper cultivars and 2 sweet pepper cultivars to napropamide and pendimethalin were evaluated under defferent conditions of soil texture, organic matter, soil temperature and seeding depth in the greenhouse. Growth response of 4 pepper cultivars was also examined by roos dipping to napropamide and pendimethalin. More inhibition of top leaf growth by root dipping to napropamide was occurred in red pepper cultivars than in sweet pepper cultivars. However, sweet pepper cultivars showed more severe inhibition of top leaf growth by root dipping to pendimethalin compared to red pepper cultivars. Crop injury due to napropamide and pendimethalin was more severe in sandy soil than in loam soil and this trend was more remarkably shown in sweet pepper cultivars. Crop injury due to napropamide and pendimethalin was reduced with the increase in organic matter especially in cv. Walgeykwan and cv. Orient al Pimento. As seeding depth of pepper cultivars became deeper, crop injury due to napropamide and pendimethalin was reduced in cv. Walgyekwan and cv. Oriental Pimento.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.214-223
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• 1995

Tolerant corn cultivars to bentazon were selected and tolerance mechanism of corn cultivars to bentazon was studied by determining bentazon 6-hydroxylase(B6H) activity which was known to detoxify bentazon to 6-hydroxy bentazon at induced enzyme conditions with treatments of 1,8-naphthalic anhydride, ethanol and phenobarbital. Tolerant cultivars to bentazon were selected by growth response of corn by foliar application of bentazon to corn cultivars. Kwanganok, GA 209, IK 2, DB 544, and Suwon 19 were tolerant to bentazon, but KSS 3, KSS 4, KS 5, and Danok 2 were susceptible. Pretreating corn seeds with 1,8-naphthalic anhydride increased B6H activity at all cultivars, but the tendencies were more remarkable at Suwon 19 and GA 209, tolerant cultivars, than at Danok 2 and KS 5, susceptible cultivars. Treating corn shoots with ethanol increased B6H activity at Suwon 19 and GA 209. B6H activity was enhanced by treatments of ethanol at 1.0 or 2.5%, but decreased at ethanol 2.5 or 5.0% at Danok 2 and KS 5. Treating corn shoots with phenobarbital increased B6H activity at Suwon 19, GA 209, Danok 2, and KS 5 by treatments of phenobarbital at 2.0mM, but decreased at 4.0 or 8.0mM at all cultivars. Therefore, the tolerant mechanism of corn cultivars to bentazon may be explained partially by the activity of bentazon 6-hydroxylase which detoxifies bentazon to 6-hydroxy bentazon.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.325-333
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• 1997

Selection of pepper (Capsicum sp.) cultivars tolerant to acetolactate synthase (ALS)-inhibiting herbicides {imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-ethyl-3=pyridine-carboxylic acid, and primisulfuron methyl 2-[[[[[4,6-bis(difluoromethoxy)-2-pyrimidinyl]amino] carbonyl]amino]sulfonyl]benzoate} was investigated. Pepper cultivars such as Red Top, Happy Dry, Golden Tower, and Hagyeorae showed relatively tolerant response to imazethapyr, while cultivars; Korea, Cheongyang, Oriental Glory, and Hanam were susceptible. Red Horn, Jopoong, Kwangbok, and Wangcho cultivars were tolerant to primisulfuron whereas Korea, Dahhong, Chamjoah, and Poongchon cultivars were susceptible. Determination of growth inhibition by ALS-inhibiting herbicides showed that the $I_{50}$ estimates of growth from the susceptible- and tolerant-cultivars were 0.075 and 0.20kg ai/ha for imazethapyr; 0.06 and 0.16kg ai/ha for primisulfuron, respectively. Furthermore, the $GR_{50}$ estimates of growth from the susceptible and tolerant cultivars were 0.05 and 0.20kg ai/ha for imazethapyr; 0.07 and 0.16kg ai/ha for primisulfuron, respectively. This result, based on the $GR_{50}$ and $I_{50}$ values, indicates that responses of pepper to ALS-inhibiting herbicides between tolerant- and susceptible-cultivars were different about 3- to 4-fold to imazethapyr, and 2- to 3-fold to primisulfuron.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.150-159
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• 1996

This study was conducted to investigate the inhibition of protox activity and the PPIX accumulation of the oxyfluorfen-tolerant and-susceptible rice cultivars with barnyardgrass, a typical susceptible weed in accordance by oxyfluorfen treatment. The susceptible rice cultivars and barnyardgrass showed more inhibition of protox activity due to the treatment of oxyfluorfen than the tolerant rice cultivars. Especially in the concentration at $10^{-6}$M treatment, protox activity of the susceptible rice cultivars and barnyardgrass were the completely inhibited but the tolerant rice cultivars kept 32~59% of activity compared to the control. As the treatment concentration increased, the content of PPIX accumulation increased and it increased untill four hours of light exposure but it tended to decrease these after. The content of PPIX accumulation by the treatment of oxyfluorfen was more pronounced in the light condition than in the dark. Under the light and dark conditions, the susceptible rice cultivars and barnyardgrass showed more PPIX accumulation than the tolerant rice cultivate. Especialiy the susceptible barnyardgrass had more than the rice. With the treatment of GC and DA, tetrapyrrole biosynthesis inhibitor, the herbicidal activity by oxyfluorfen was inhibited, and the susceptible rice cultivars and barnyardgrass tended to have less effective than the tolerant rice cultivars and the content of chlorophyll or PPS accumulation tended to be similar.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.362-371
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• 1996

In this study, the relationships between sensitivity to oxyfluorfen, absorption of the herbicide, protoporphyrin IX(Proto IX) accumulation and activities of antioxidative enzymes were examined to identify the tolerance mechanism against oxyfluorfen in various rice cultivars having different level of tolerance to this herbicide. Absorption of oxyfluorfen in tolerant rice cultivars was slower than in susceptible cultivars. Proto IX accumulation in various rice cultivars treated with oxyfluorfen was higher in susceptible cultivars than in tolerant ones. In susceptible cultivars especially, Proto IX accumlated rapidly during the herbicide treatment in the dark. Large amounts of Proto IX accumulation were considered to cause membrane lipid peroxidation in the light. However, among the tested rice cultivars, there was little relationship between their tolerance to oxyfluorfen and the activities of antioxidative enzymes. Therefore, it is assumed that differential susceptibility of rice cultivars to oxyfluorfen was due to difference in their capability to absorb the herbicide and to subsequently accumulate Proto IX.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.259-268
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• 2013

This study was carried out to evaluate the visual turfgrass's color quality, winter color, and spring green-up under three different soil systems and to make a practical use for sports turf design and construction. Several turfgrasses were evaluated in multi-layer, USGA and mono-layer systems. Turfgrass entries in the study comprised of 3 cultivars from Korean lawngrass (Zoysia japonica Steud.) of typical warm-season grass (WSG) and 3 blends and 3 mixtures from Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.) of cool-season grass (CSG). Significant differences were observed in the turfgrass's color quality, winter color, and spring green-up in the study. Seasonal variation of visual turf color greatly occurred according to soil systems and turfgrasses. Multi-layer and USGA systems were highly associated with better visual color ratings, as compared with mono-layer system. Regardless of soil system, visual turf color in all entries was better from spring to fall than in winter. Great color differences were observed during a period of early December to early spring. CSG produced a better color quality over WSG in any soil system. Overall color ratings for CSG were KB > PR > Mixtures > TF. As for a winter color, its ranking was USGA > multi-layer > mono-layer system. No difference was found in winter among cultivars of Korean lawngrass, being completely brown, but great differences among CSG. Rated best for winter color was PR, followed by CSG mixtures, KB and finally TF in order. It was generally conceded that fast green-up in spring was greatly related with multi-layer over mono-layer system and also CSG over WSG. Among CSG, TF had a fastest green-up. PR was also fast in green-up, but poor in color uniformity. KB, however, was the slowest due to shallow rooting system, when compared with other CSGs. These results demonstrate color differences were greatly variable according to soil systems and also among turfgrass species. A precise decision should be made in selecting turfgrass species and soil system. Multi-layer and USGA systems were considered as the suitable one for turfgrass color quality, winter color and spring green-up. It is a great necessity to combine proper soil system, right turfgrass species, and appropriate mixing rates by a concept-oriented approach, when establishing garden, parks, soccer field, and golf courses and so on.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.89-95
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• 2012

Korean lawn grass, which belongs to Zoysia genus in Gramineae family, is one of the major turfgrass which is widely adapted to its native niches in the temperate region of the north east Asia through tropical regions including Philippine, Thailand and Australia. The Turfgrass Information Center' database provides 5,340 descriptive records including 638 referred papers and 1,370 technical reports concerning 'Zoysia'. The database focused on researches on golf courses and lawn care industries. The researches provide informations on seed technology and use of plant protectant for pest management in turf management industries. The purpose of this study is to analyze and classify the research contents of zoysiagrasses which have been published in Korean journals. The total number of research papers published in Korean journals were 274 including 102, 38, and 134 in the 'Botanical', 'Environmental' and 'Cultural' researches, respectively. Publication in foreign journals by Korean investigators were not counted in this research. Research fields concerning golf course maintenance and plant protectant are believed to be necessary when compared to international trends. Moreover, advanced research efforts for the development of new cultivars with various environmental and disease resistance should be accomplished.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.5
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• pp.40-47
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• 2003

This study examined the improved effect of wear tolerance of warm-season turfgrass overseeded with cool-season turfgrasses. Also, it investigated the improved effect of crumb rubber on wear tolerance and the difference anmong cultivars regarding the wear of Zoysia spp. In wear experiment during summer, the warm-season turfgrass overseed with cool-season turfgrasses had a higher visual rating on the ground than the monostand of Cynodon dactylon. Moreover, in wear experiment in winter, barrenness showed significant progress in the monostand of C. dactylon, while the barrenness did not appear at all in overseeded turf with cool-season turfgrasses. As a result of investigating the bulk density was increased in the monostand of C. dactylon, but not in the overseed turf with cool-season turfgrasses. From the above result, the wear tolerance effcect of turfgrasses appeared year round through warm-season and cool-season turfgrass mixtures. Also, it was found that the method of topdressing crumb rubber on the ground was effective as a physical assistant device alleviating damage of turfgrasses. The possibility of improving wear tolerance was accepted by adding soil amendments such as perlite, pamis, etc., in order to promote the growth of turfgrass.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.295-306
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• 2009

We investigated the quality of 48 cultivar in 5 types, most popularly used in Korea golf courses. Only brown patch disease caused by Rhizoctonia solani AG1-1 was occurred naturally. While disease was developed seriously into tall fescue cultivar in spring time and into bentgrass cultivar in fall time, respectively, however, among species were not significantly different. Tall fescue and perennial ryegrass cultivar had higher chlorophyll contents in November and there were also significantly different between cultivar of tall fescue, kentucky bluegrass and fine fescue species. Turfgrass color also showed significant difference between grass species. Perennial ryegrass has the highest value of turf leaf color, followed by kentucky bluegrass and tall fescue species. Significant differences among cultivar were found in kentucky bluegrass, tall fescue and fine fescue. Although fresh weight of turfgrass was not statistically different between grass species, root length was significantly different between species. Tall fescue species had the longest root length. Fresh weight showed differences among cultivar in kentucky bluegrass, bentgrass and tall fescue species. Based on our results, growth and grass quality showed large differences among cultivar and each turfgrass species.