• Korean Journal of Weed Science
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• v.1 no.1
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• pp.30-43
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• 1981

On unwedded paddy fields, six cropping patterns of rice cultivation, namely direct broadcast seeding, direct row seeding, machine transplanting, early season hand transplanting, standard season hand transplanting, and late season hand transplanting, were detected with two representative rice cultivars (Milyang 23 and Sadominori) to estimate the comparative fluctuation patterns of weed flora. As a result, number of emerged weed species, most crowding stages, differences of weed growth among cropping patterns, possible tendencies of competition in plant heights among plant groups, variations in Importance Values, and Simpson's Index analysis were discussed, respectively.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.250-257
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• 1988

The study was intended to know any relations between the rice tolerance to bensulfuron and varietal speciation in seed protein composition or any enzymatical allelies with or without chemical treatment. Rice varieties used were UCP-28, Chinsurah Boro II, Fukunohama, Fadehpur-2, IR 14252-13-2-2-5 as the tolerant group, and HP 93(3) FA, HP94(9) FA, Padilabou Alumbis, KH-17854, and IR 1846-2841-1 as the susceptible, respectively. Electrophoretic methods used were SDS-PAGE for seed protein, 7% PAGE for isozymes (acid phosphatase, peroxidase, malate dehydrogenase, and esterase from rice seedling) and variation in isoenzyme profiles (malate dehydrogenase, peroxidase, and esterase) as affected by different concentrations of bensulfuron(0, $10^{-6}$, $10^{-5}$ and $3{\times}10^{-5}M$) was also studied. The results are summarized as follows. -Among 16 bands separated in seed proteins, two different rice groups selected in terms of tolerance to bensulfuron were clustered in dissimilarity, which was based on relatively larger area in whole peaks and higher activities in N, O, P bands for the tolerant group. -Among isozymes obtained from rice seedlings without chemical treatments, the following specificities were obtained. The tolerant varieties had the relatively higher activity in D band out of 4 peroxidase bands. Malate dehydrogenase was separated into 3 bands and only tolerant varieties had A band and higher activities in Band C bands. Esterase was separated into 3-4 bands with higher activities in A and B bands for tolerant varieties. There were one major band accompanied by 2-3 minor bands for acid phosphatase in which only tolerant varieties had the B band. -The effect of Bensulfuron concentration on the isozyme activities showed that the activity of C band in peroxidase was not present in tolerant varieties which was contrary to the increased activities in susceptible varieties. However, D band was gradually disappeared only in susceptible varieties as the concentration of bensulfuron was increased. For malate dehydrogenase in the susceptible varieties, major bands D, E and F kept consistantly higher activities while minor bands A, B and C disappeared sensitively. Among 5 bands of esterase separated, D band was present only in the tolerant varieties while E band only in the susceptible. The activities in A, C, E bands were sharply decreased in the susceptible varieties as the concentration of bensulfuron was increased.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.183-200
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• 1989

An experiment was conducted at the greenhouse of the International Rice Research Institute in 1987 to find out the character of dry matter production, the potential seed production ability and the ecological and physiological strategies to adaptation. For these, two rice cultivars, IR64(lowland rice) and UPLRi-5(upland rice), and seven weed species were used ; Echinochloa glabrescens Munro ex Hook. f., E. cress-galls ssp. hispidula (Retz.) Honda, E. colons (L.) Link, Monochoria vaginalis (Burin. f.), Ludwigia octovalvis Jacq.) Raven, Fimbristylis miliacea Vahl and Cyperus difformis L. Adaptation strategies of weed species varied by species. However, they had efficient seed production strategy through different ways. In general, sedge weed species (F. miliacea and C. difformis) produced great amount of seeds at the expense of seed size through greater ratooning ability and low relative dry weight for flowering. For broadleaved weed species, greater number of descendants were obtained through high plasticity and low relative dry weight for flowering (M. vaginalis) or greater growth ability through effective photosynthetic efficiency (L. octovalvis). Grass weed species, on the other hand, produced their seeds through effective growth (net assimilation rate and relative growth rate), high ratooning ability (except E. crus-galls ssp. hispidula) or low relative dry weight to maximum dry weight for flowering (E. glabrescens). The harvest indices of the weed species were considerably lower than those of rice. Fimbristylis miliacea had the greatest ratooning ability followed by C. difformis, E. colons and E. glabrescens. The greatest seed productivity was recorded by C. difformis (279, 000) and L. octovalvis (268,000) while rice produced the least number of seeds (1300-6100). Log seed weight had a negative linear relationship with log seed number (y=6.30-1.48X, $R=-0.965^{**}$). For all species plant plasticity response was not directly correlated with mortality response.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.1
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• pp.39-46
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• 2011

This study was carried out to determine the forage yield, quality, and regrowth of Italian ryegrass (IRG) and barley sown on 2 March 2009 in Suwon. The five treatments were two IRG cultivars (Kowinearly with early maturity and Kowinmaster with medium maturity), one barley cultivar (Yuyeon), and two mixtures (Kowinearly + Yuyeon and Kowinmaster + Yuyeon). The first harvest date was 26 May, which was at late heading, heading and early dough stage of Kowinearly, Kowinmaster and barley, respectively. Regrowth yield was investigated on 29 June. The heading dates of Kowinearly and Kowinmaster were 16 May and 22 May, respectively, and that of barley was 13 May. The dry matter (DM) percentage were 13.0~18.4% at first harvest, and 22.5~24.8% at regrowth in all treatments. The forage yield of barley and Kowinmaster + Yuyeon mixture at first harvest was higher than that of IRG (p<0.05), but higher regrowth yield was observed in IRG, and then IRG + barley mixtures (p<0.05). The crude protein (CP) content and in vitro DM digestibility (IVDMD) of IRG at first harvest were 16.7~17.1% and 78.3~80.4%, respectively, which were higher than those of barley (CP 12.2% and IVDMD 72.6%) and IRG + barley mixtures. The total yields of DM, CP and digestible DM were high in Kowinmaster + Yuyeon mixture as 11,628 kg, 1,669 kg and 8,457 kg per ha, respectively. In conclusion, spring seeding of IRG + barley mixtures and/or barley were recommended when early harvest. Regrowth of IRG sown in early spring was vigorous. Mixture cultivation of IRG and barley was effective, because of forage yield and stable production, and harvest at June instead of May was desirable for forage productivity of spring sown IRG and barley.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.782-789
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• 2013

Carrot (Daucus carota L. var. sativa) is one of the most widely used crops in the world and is nutritionally important crop. However, seed-hair which is generated in epidermal cell of seeds causes the difficulty of the seedling process, because of the seed germination and absorption inhibitions. For these reasons, carrot seeds are commercialized after mechanical hair removal process. However, in this process, various damage and seed loss occur and breeding of hairless-seed carrot cultivar is needed to overcome these various weaknesses and additional seed production costs. In this study, cDNA libraries using 2 combinations, which were composed of short-hair seed CT-ATR 615 OP 666-13 & long-hair seed CT-ATR 615 OP 671-9, and short-hair seed CT-SMR 616 OP 659-1 & long-hair seed CT-SMR 616 OP 677-14, were constructed and EST sequences of each individuals were analyzed to reveal carrot seed-hair characteristics. Firstly, analyzed EST sequences were classified into FunCat functional categories. As a result, significant differences have been identified in metabolism category, protein folding and stabilization, protein binding, C-compound binding category from both of two combinations. Secondly, several candidate EST sequences related to seed trichome differentiation and cellulose biosynthetic process were selected based on GO data of EST sequences. These differences based on FunCat categories and candidate EST obtained by GO data analysis are thought to be involved in the formation of carrot seed hair. Finally, 741 SSR sites and 33 SNP sites were identified from analyzed EST sequences of two combinations. Then we designed SNP and SSR primer sets to develop molecular markers. These molecular markers will be used for classification of carrot cultivars and study seed-hair characteristic.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.344-360
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• 2017

Zoysiagrasses are important turf plants used for school playgrounds, parks, golf courses, and sports fields. The two most popular zoysiagrass species are Zoysia japonica and Zoysia sinica. These are widely distributed across different growing zones and are morphologically distinguishable from each other; however, it is phenotypically difficult to differentiate those that grow along the coastal line from those in beach area habitats. A combination of morphological and molecular approaches is desirable to efficiently identify these two plant cultivars. In this study, we used a rapid identification system based on DNA barcoding of the nrDNA-internal transcribed spacer (ITS) regions. The nrDNA-ITS regions of ITS1, 5.8S nrDNA, and ITS2 from Z. japonica, Z. sinica, Agrostis stolonifera, and Poa pratensis were DNA barcoded to classify these grasses according to their molecular identities. The nrDNA-ITS sequences of these species were found at 686 bp, 687 bp, 683 bp, and 681 bp, respectively. The size of ITS1 ranged from 248 to 249 bp, while ITS2 ranged from 270 to 274 bp. The 5.8S coding region ranged from 163 - 164bp. Between Z. japonica and Z. sinica, nineteen (2.8%) nucleotide sites were variable, and the G+C content of the ITS region ranged from 55.4 to 63.3%. Substitutions and insert/deletion (indel) sites in the nrDNA-ITS sequence of Z. japonica and Z. sinica were converted to cleaved amplified polymorphic sequence (CAPS) markers, and applied to the Zoysia grasses sampled to verify the presence of these markers. Among the 62 control and collected grass samples, we classified three groups: 36 Z. japonica, 22 Z. sinica, and 4 Z. japonica/Z. sinica hybrids. Morphological classification revealed only two groups; Z. japonica and Z. sinica. Our results suggest that used of the nrDNA-ITS barcode region and CAPS markers can be used to distinguish between Z. japonica and Z. sinica at the species level.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.17-28
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• 2007

This study was conducted to analyze the optimum heading period according to the recent climatic change for improvement of rice yield and grain quality in the Yeongnam area. We analyzed climatic elements including daily mean air temperature, daily range of air temperature, sunshine hours, and amount of precipitation from 1996 to 2005 in comparison with those of the 1971 to 2000 normal. Daily mean air temperature and amount of precipitation in the recent 10 years increased, but daily range of air temperature and sunshine hours decreased in comparison with the norm. Also, monthly mean air temperature was lowered remarkably in July and August. The monthly amount of precipitation largely increased in August and September. The daily range of air temperature and sunshine hours were greatly decreased from August to October, Possible cultivation periods for rice in the recent 10 years ranged from 171 days in Boughwa to 228 days in Busan and was expanded about $1{\sim}13$ days in comparison with the normal. Optimum heading date by local regions for the maximum climatic yield potential was estimated as July 31 at Bonghwa to September 7 at Busan, Masan, and Tongyeong in the recent 10 years. There was a wide difference in optimum heading date according to local legions of the Yeongnam area. Compared to the normal, optimum heading date in the recent 10 years was delayed about I~8 days in most local regions except Bonghwa, Mungyeong, and Yeongdeok. These results suggested that it is necessary to develop late maturity rice cultivars for producing high yield and quality rice grain due to the recent climatic change. Moreover, it is still more important to select the most suitable cultivation period appropriate to the changed climate of each local region in Yeongnam area.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.108-115
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• 1989

An experiment was carried out at the International Rice Research Institute in 1987 to understand the seed germination and seedling development of rice and Echinochloa species. The percentage germination of rice cultivars(IR64 for lowland-type and UPLRi-5 for upland-type) was extremely high(>90%) regardless of temperature while that of Echinochloa species ranged from 10 to 80% depending on the species. Among these, E. crus-galli ssp. kispidula had the lowest germination with less than 20% at the high temperatures ($30^{\circ}C$, $35^{\circ}C$) and about 45% at the low temperature ($25^{\circ}C$). Original seed weight gradually decreased with time white root and shoot weight increased for both rice and Echinochloa species. However, increase in root and shoot weight did not compensate for the loss of stored carbohydrate during the experimental period. The root of E. glabrescens grew from the seed on the opposite side of the shoot while for rice it grew from the same side of the seed as the shoot. Echinochloa glabrescens had a leaf blade-like expanded first leaf that contained chlorophyll while rice had an incomplete first leaf that had no leaf blade and no chlorophyll. Due to this E. glabrescens could grow independently 2 to 3 days earlier than rice.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.203-211
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• 2017

This study was conducted to investigate the phytotoxicity of main rice varieties and control efficacy of HPPD inhibitor to major paddy weeds at the time of temperature rise due to climate change. Phytotoxicity of herbicide to rice was increased as temperature was increased, and more severe in root than shoot. The phytotoxicity of japonica rice cultivars for the rice were mild enough to recover. However, glutinous rice, super high yield rice, and Tongil rice varieties were damaged enough to decrease the yield. Shindongjinbyeo transplanted by June 15, showed phytotoxicity enough to recover. However, in the rice field on June 30 and on July 15, the rice showed a remarkable inhibition. The control effect of Monochoria vaginalis and Scirpus juncoides was more than 90% under the temperature condition controlled artificially. However, Echinochloa oryzicola was controlled 40% at $27.5^{\circ}C$, which is a high temperature condition. In rice fields with different transplanting times, annual weeds except for E. oryzicola were highly controlled by 90% or more regardless of the time of transplanting.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.2
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• pp.74-87
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• 2016

Potato phenology, growth, and yield are projected to be highly affected by global warming in the future. The objective of this study was to examine the responses of potato growth and yield to environmental elements like temperature, solar radiation, and daylength. Planting date experiments under open field condition were conducted using three cultivars differing in maturity group (Irish Cobbler and Superior as early; Atlantic as mid-late maturing) at eight different planting dates. In addition, elevated temperature experiment was conducted in four plastic houses controlled to target temperatures of ambient temperature (AT), $AT+1.5^{\circ}C$, $AT+3^{\circ}C$, and $AT+5^{\circ}C$ using cv. Superior. Tuber initiation onset was found to be hastened curve-linearly with increasing temperature, showing optimum temperature around $22-24^{\circ}C$, while delayed by longer photoperiod and lower solar radiation in Superior and Atlantic. In the planting date experiments where the average temperature is near optimal and solar radiation, rainfall, pest, and disease are not limiting factor for tuber yield, the most important determinant was growth duration, which is limited by the beginning of rainy season in summer and frost in the late fall. Yield tended to increase along with delayed tuber initiation. Within the optimum temperature range ($17^{\circ}-22^{\circ}C$), larger diurnal range of temperature increased the tuber yield. In an elevated temperature treatment of $AT+5.0^{\circ}C$, plants failed to form tubers as affected by high temperature, low irradiance, and long daylength. Tuber number at early growth stage was reduced by higher temperature, resulting in the decrease of assimilates allocated to tuber and the reduction of average tuber weight. Stem growth was enhanced by elevated temperature at the expense of tuber growth. Consequently, tuber yield decreased with elevated temperature above ambient and drop to almost nil at $AT+5.0^{\circ}C$.