• Korean Journal of Weed Science
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• v.30 no.2
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• pp.103-110
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• 2010

This experiment was conducted to investigate seedling emergence and early growth of Monochoria vaginalis and Scirpus juncoides in the controlled-environment chamber maintained at different temperatures. Non-linear regression analyses of observed data against effective accumulated temperature (EAT) with the Gompertz and logistic models showed that the Gompertz and logistic models worked well in describing seedling emergence and early growth of both weed species, respectively, regardless of temperature. EATs required for 50% of the maximum seedling emergence and the maximum leaf number of M. vaginalis were estimated to be 69.3 and $131^{\circ}C$, respectively, while those of S. juncoides were 94.8 and $137^{\circ}C$, respectively. Models developed in this study thus were used to predict seedling emergence and early growth under elevated temperature condition. If rotary tillage with water is made on 27 May under $+3^{\circ}C$ elevated temperature condition, dates for 50% of the maximum seedling emergence and 4 leaf stage were predicted to be 1 June and 15 June for M. vaginalis and 3 June and 14 June for S. juncoides, respectively. As compared with current temperature, these dates are 1-2 days earlier for the seedling emergence and 3 days earlier for the early growth, suggesting that earlier application of herbicides is required for effective control of M. vaginalis and S. juncoides under elevated temperature condition in the future.

• Korean Journal of Plant Resources
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• v.32 no.6
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• pp.683-688
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• 2019

This study was conducted to determine the number of days required to break a plant's dormancy and promote subsequent crop growth in new varieties of Gomchwi through the 4℃ treatment. Three new varieties of Gomchwi namely, 'Sammany', 'Gommany', and 'Damogy' were observed in this study. The rate of leaf emergence of 'Sammany' after 15-day of 4℃ treatment was 100%, while 'Gommany', and 'Damogy' took 20-days and 10-days, respectively to reach to 97.9% rate of leaf emergence. After 10-days of 4℃ treatment, 'Damogy' grew faster than the other varieties. and Harvest time for 'Damogy' was on January 18^th, after 5-days of 4℃ treatment and yield was observed to be the highest at 15-days of 4℃ treatment. 'Sammany' was next with a minimum of 10-days of 4℃ treatment, although 15-days is more preferred for better harvest. 'Gommany' on the other hand, did not grow enough for harvest by January 18^th, and its harvest time was delayed to January 31^st. It needed a minimum of 15-days and preferentially 20-days of 4℃ treatment to grow normally and be ready for harvest. The plant height, leaf length and leaf petiole length appeared to grow better by extending duration of the 4℃ treatment. The number of leaves of 'Sammany' and 'Gommany' varieties was three leaves for the 5-days treatment which may be due to the incomplete breaking of dormancy. Regarding the yield per plant, 'Sammany' yielded 112.3 grams (g) in 15-days treatment, and 'Gommany' yielded 106.5 g in 25-days treatment. In the case of 'Damogy', it yielded 123.5 g and 183 g in the 10-days and 25-days treatment respectively. It is concluded that 'Damogy', 'Sammany' and 'Gommany requires 10, 15, and 20 days of 4℃ treatment to break the plant's dormancy and promote better plant growth.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.335-343
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• 2003

An experiment was conducted to investigate types of injury inflicted by the stone leek leafminer, Liriomyza chinensis Kato (Diptera: Agromyzidae) on welsh onion. A feeding scar made by an adult female was a hole round in shape, with diameter of 0.08 mm and 0.48 mm in lesion, resulting in a white spot, many of which often form vertical dotted lines on a leaf. Egg spots were oval with 0.1 ${\times}$0.14 mm in size, one or several of which often form a V-shape in group. Feeding by adults began immediately after emergence and was very active from 4th to 5th day. Oviposition was done from 2nd to 6th day after emergence. In both feeding and oviposition, they were more active in the day time. Larvae after emergence crawled up the leaf at first, and then moved up and down to feed on mesophyll. When in high density, they feed on leaf from leaf tip to bottom, and let the leaf die. Area of damage per one larva was calculated as 72.1 $\textrm{mm}^2$. The aged larvae escaped from the leaf in early morning, usually between 5 and 7 am. Most pupation sites were distributed near plants,5cm in soil depth and within 10 cm away from the plant. Pupae of L. chinensis overwintered 10cm below soil surface and emerged from early May to late June the next year Adults then moved to welsh onions near over wintering sites, nursery, transplanted, and levee.

• Journal of Environmental Science International
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• v.33 no.6
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• pp.383-402
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• 2024

Variations in lettuce growth and quality were observed depending on the type of artificial light source. The RGB LED treatment resulted in thick leaf development, leading to higher fresh weight, dry weight, and relative growth rates. Two cultivars, "Tomalin" and "seonpunggold," exhibited increased anthocyanin content and dark red leaf color under conditions of RGB LED treatment. Additionally, they exhibited high chlorophyll content under conditions of RGB LED and RGBFR LED treatments. Particularly, under Red LED treatment, the plants showed elongated leaves with narrow widths, resulting in a higher leaf shape index and a tendency towards leaf curling. Therefore, RGB LED lighting which appropriately blends red, blue, and green lights, is more effective than single lighr sources at improving lettuce growth and quality.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.158-163
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• 1983

The purpose of this experiment was to find out fundamental data for the cultivation of sorghum-sudangrass hybrid. Leaf area index and dry matter accumulation were investigated with 3-levels of nitrogen application,15, 25, 35kg per 10a during the period of initial growth from the 8th leaf emergence to the late blooming stage. The results obtained were as follows: Leaf emergence increased as growth progressed and in the same pattern at all N-levels. After the heading stage, the value was 15 at all N-levels. Leaf area index (LAI) increased as growth progressed and rapidly till the booting stage. At 15kg N-level the values were larger till the ear formation stage, and at 35tg N-level the values were larger than other N-levels after the booting stage. At the late blooming stage LAI reached 8.13 at 35kg N-level. The value of dry matter accumulation was the highest at 35kg N-level at the late blooming stage, and as was the same in the value of crop growth rate (CGR). There was a tendency that before the booting stage the enlargement of leaf area contributed to dry matter accumulation and after the booting stage did the increase of net assimilation rate (NAR) .

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.434-439
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• 2008

The amount of salt to make seed sorting solution of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18 L water, which is lower amount than currently used. Five rice cultivars were examined. Percent germination and seedling emergence were not similar. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. However, if seeds with low speicific gravity are produced due to the bad grain filling condition and consequently total seed content of low specific gravity increases, results will be differnt. Reduction in total growth and yield could occur. It will be important to comply with the seed sorting criterion of 1.13 for Japonica, 1.06 for Tongil, and 1.04 for waxy rice variety to ensure the maximum rice growth and yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.366-369
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• 2000

This study was conducted to determine the effect of seeding date on the days and the accumulated temperatures to development stages, leaf emergence, and yield in spring-planted barley. Two barley varieties, Sacheon #6 in spring type (growth habit I) and Saechalssalbori in winter type (growth habit IV), were seeded on four seeding date, Feb. 23, March 4, March 13, and March 24. Growth periods to emergence, heading and maturity were shorten when seeding dates were delayed, except for the heading date of Saechalssalbori (winter type barley)at the later seeding date. The rate of leaf emergence was 0.1915 in a day, and was slightly high when seeding was delayed. The accumulated temperatures were 111-142$^{\circ}C$ for emergence, 683-756$^{\circ}C$ for heading, and 1274-1326$^{\circ}C$ for maturity. In general, the accumulated temperature to heading was higher in Saechalssalbori than in Sacheon #6 because the winter growth habit of Saechalssalbori was not removed perfectly, One-thousand grain weight and yield were reduced by delayed seeding. In order to reduce the yield when barley were planted in spying, it is desirable to select the spring type varieties, and to plant them as early as possible.

• Journal of Ecology and Environment
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• v.33 no.4
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• pp.299-306
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• 2010

The use of local seed provenance is often recommended in forest restoration. Early vigor is a combination of the performance of seed germination and emergence after planting. The ability of young Brant's oak plants to grow and develop after emergence and its dependence on local habitat conditions was investigated in this study. The effects of seed source and shade on early growing seedlings of Brant's oak (Quercus brantii L.) were determined in field measurements. Seeds of Quercus brantii L. were collected from 4 forest areas (seed sources) in southern Zagros (Provinces of Kohkilouyeh-Bouyer Ahmad and Fars) at altitudes of 850, 1,100, 1,500, 2,100 m a.s.l., and planted in a nursery constructed in southwestern Iran. According to a split-plot design consisting of four blocks, each containing two main treatment plots (no shading, partial shading), each main plot was sub-divided into four sub-plots (for elevations of 850, 1,100, 1,500 and 2,100 m). Results showed that shade treatments had significant effects on emergence percentage and rate, shoot length, shoot dry weight (SDW), root dry weight (RDW), leaf area (LA), and chlorophyll content. Ecological factors also had an effect on seed performance. Altitude of seed source had a very significant effect on root length, LA, SDW, and RDW. The seeds collected from 850 m a.s.l. elevation showed the highest performance, especially in leaf area, root length, shoot dry weight, and root dry weight. Our results showed that the altitude of 850 m a.s.l. was the best for collecting Brant's oak seeds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.149-153
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• 1999

Prediction of rice developmental stage is necessary for proper crop management and a prerequisite for growth simulation as well. The objectives of the present study were to find out the relationship between the plastochrone index(PI) and the developmental index(DVI) estimated by non-parametric phenology model which simulates the duration from seedling emergence(DVI=0) to heading(DVI=l) by employing daily mean air temperature and daylength as predictor variables, and to confirm the correspondency of developmental indice to panicle developmental stages based on this relationship. Four japonica rice cultivars, Kwanakbyeo, Sangpungbyeo, Dongjinbyeo, and Palgumbyeo which range from very early to very late in maturity, were grown by sowing directly in dry paddy field five times at an interval of two weeks. Data for seedling emergence, leaf appearance, differentiation stage of primary rachis branch and heading were collected. The non-parametric phenology model predicted well the duration from seedling emergence to heading with errors of less than three days in all sowings and cultivars. PI was calculated for every leaf appearance and related to the developmental index estimated for corresponding PI. The stepwise polynomial analysis produced highly significant square-rooted cubic or biquadratic equations depending on cultivars, and highly significant square-rooted biquadratic equation for pooled data across cultivars without any considerable reduction in accuracy compared to that for each cultivar. To confirm the applicability of this equation in predicting the panicle developmental stage, DVI at differentiation stage of primary rachis branch primordium was calculated by substituting PI with 82 corresponding to this stage, and the duration reaching this DVI from seedling emergence was estimated. The estimated duration revealed a good agreement with that observed in all sowings and cultivars. The deviations between the estimated and the observed were not greater than three days, and significant difference in accuracy was not found for predicting this developmental stage between those equations derived for each cultivar and for pooled data across all cultivars tested.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.94-102
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• 2010

Field and pot experiments were conducted to investigate seedling emergence and early growth of Eleocharis kuroguwai panted on different dates. Non-linear regression analyses of observed data against effective accumulated temperature (EAT) with the Gompertz model showed that the Gompertz model works well in describing seedling emergence and early growth of E. kuroguwai regardless of planting date and soil burial depth. EATs required for 50% of the maximum seedling emergence of E. kuroguwai planted at 1, 3 and 5 cm soil burial depth in the pot experiment were estimated to be 54.5, 84.0 and $118.0^{\circ}C$, respectively, and $56.7^{\circ}C$ when planted at 1 cm in the field experiment. EATs required for 50% of the maximum leaf number of E. kuroguwai planted at 1, 3 and 5 cm soil burial depth in the pot experiment were estimated to be 213.3, 249.0 and $291.6^{\circ}C$, respectively, and $239.5^{\circ}C$ when planted at 1 cm in the field experiment. Therefore, models developed in this study thus predicted that if rotary tillage with water is made on 27 May under $+2^{\circ}C$ elevated temperature condition, dates for 50% of the maximum seedling emergence, 5 leaf stage and 5 cm plant height of E. kuroguwai buried at 3 cm soil depth were predicted to be 2 June, 10 June and 12 June. These dates are 1 day earlier for the seedling emergence and 3 days earlier for the early growth as compared with current temperature condition, suggesting that earlier application of herbicides is required for effective control of E. kuroguwai.