• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.24-29
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• 1997

This study was conducted to evaluate the effect of locations and nursing days on the cstablishment and the first-year growth of Aster scaber seedlings in mountainous areas. Survival rates of the seedlings ranged from 72% in Bukbang to 27% in Mt. Yeonyup B. Survival rate of 90 days-seedlings was 65%. 150days-and 120days- seedling had 2 or 3 leaves but it was almost same as that of native plants. The plants grown in Mt. Yeonyup A averaged 10.7cm high and 90 days-seedlings grew best. Dry weight of plants grown from 120 days- and 90days- seedlings was respectively 215mg and 205mg.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.413-420
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• 2017

Sugarbeet cyst nematode (Heterodera schachtii) has recently been detected as a severe pest of Chinese cabbage fields in Korea. Two studies were performed to evaluate the effect of inoculation density of H. schachtii and plant age of Chinese cabbage on the final population of the nematodes. Chinese cabbage inoculated with high inoculation density (4 juveniles or eggs/g soil) showed significant differences in the number of cysts, females and eggs. The 40 day- old plants inoculated with high nematode densities yielded the highest nematode populations after 30 and 60 days of inoculation, compared with other plant age groups (0, 20, 30 day-old)used in the experiment. We, thus, summarize that, maximum nematode multiplication rates are made on comparatively older plants at the high nematode densities. Therefore, taking plant age into consideration at the transplanting of Chinese cabbage was recommended for the management of H. schachtii.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.390-399
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• 2020

We investigated the effect of seedling age and planting density on early growth performance of Zelkova serrata trees. Containerized Z. serrata seedlings, 1-year-old and 2-year-old, were planted according to two different planting densities (3,000 and 5,000 trees ha-1) at the end of March, 2017. Three plots were established for each treatment (2 seedling ages × 2 planting densities). We calculated the survival rate (%) of out-planted seedlings as well as the stem volume based on the root collar diameter (RCD) and height (H) in September of each year, from 2017 to 2019. Seedling age and planting density did not affect survival rate of the out-planted trees. Planting density did not affect height of the trees, whereas the treatment significantly affected RCD and the H/D ratio for 2-year-old seedlings in 2019. The stem volume per tree was highest in the plot of 2-year-old seedlings at 5,000 trees ha-1 and lowest in the 1-year-old seedlings at 3,000 trees ha-1. In addition, the tree height in both 1-year-old and 2-year-old Z. serrata trees was greater in the 5,000 trees ha-1 plot than in the 3,000 trees ha-1 plot. There was no interactive effect between seedling age and planting density on stem volume; however, as seedling age and planting density increased, stem volume of Z. serrata trees increased. The values for stem volume per hectare are 85%, 68%, and 300% higher in 1-year-old 5,000 trees ha-1, 2-year-old 3,000 trees ha-1, and 2-year-old 5,000 trees ha-1 plots, respectively, compared to the values in 1-year-old 3,000 trees ha-1. This result shows that high planting density (close planting) affects tree growth differently based on seedling age, and suggests that the planting density of 5,000 trees ha-1 is suitable for 2-year-old seedlings to improve early growth field performance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.19-23
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• 2008

This study was conducted to compare the yield and grain quality as affected by rice seedling age in late transplanted rice. The rice yield was remarkably reduced in 10 day-old seedlings but those of older seedlings over than 30-day were not different. In the rice quality, as the rice seedling age younger the rate of greened and damaged rice increased, suggesting decreasing of the head rice rate. Among the physicochemical characteristics, protein content of rice grain was increased in 10 day-old seedling but amylose content was not different, consequently, the palatability was improved in older seedlings over than 30-day. From these results, it is more beneficial to machine transplant the older seedlings over than 30-day for delayed transplanting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.68-75
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• 1978

Experiments were conducted to find out the optimum seeding rate and amounts of fertilizer application for seedling growth of five for machine transplanting. Number of leaves of seedlings increased as seeding rate decreased, but there was no significant differences in leaf number among fertilizer levels. At a seeding rate higher than 100g/box. number of leaves was less than 4.5, but more than five leaves were developed at a seeding rate of 50g/box.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.68-75
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• 1980

This study was conducted to investigate the influence of seedling age and plant density on the yield and yield components of perilla intercropped and aftercropped with tobacco. 1. In this experiments, tobacco (Hicks) was employed as a intercropped, and perilla(Suwon 8) as a inter or after cropped. 2. Three levels of 20, 30, 40 days of seedling age and 3 levels of 1, 2, 3 seedling per a hill of planting density was employed in this study. 3. As a result of this study, it may be concluded that 30-40 days of seedling age and 2-3 seedlings per a hill was most effective in the case of inter and aftercropping perilla with tobacco.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.112-119
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• 1986

The variations of antibiosis to whitebacked planthopper (Sogatella furcifera Horvath) in resistant varieties, N 22 (Wbph 1) and ARC 10239 (Wbph 2) was investigated at different seedling ages and different tillers within a plant. The antibiosis of the rice plants to the insect was measured as the nymphal survival rate on the rice plants. The survival rate of the WBPH on N 22 was greater than on ARC 10239. It was also different at different seedling ages and the tillers within a plant with different tendency of two resistant rice genotypes, N 22 and ARC 10239. NO significant differences of nymphal survival rate was found between 7 and 30 days old seedlings on N 22, and greatly reduced on the 60 days old seedling. On the other hand it was increased up to on 30 days old seedlings and gradually decreased from on 40 days old seedlings of ARC 10239. The nymphal survival rate was greater in tillers than in the main culm of the rice plants.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.248-254
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• 1990

Initial crop injury, plant growth and yield of machine-transplanted rice of seedlings different in plant age (8-, 20-, and 35-day-old seedlings) after application of herbicides were investigated in field. The herbicides employed were butachlor, dithiopyr, pyrazolate(applied only for 8-day-old seedling), dithiopyr+pyrazolate, dithiopyr+ bensulfuron methyl), and butachlor+bensulfuron methyl(applied only for 20-and 35-day-old seedlings). There was no significant difference in plant growth, yield components and yield between the different-aged seedlings of the untreated check, except for the heading date, The heading date of 8-day-old seedling was delayed for 2 and 6 days as compared with those of 20-and 35-day-old seedlings, respectively. A very slight initial crop injury was found with the tested herbicides for all the different-aged seedlings. No significant differences in plant height and tiller number occurred between different-aged seedlings and the respective untreated check. All the herbicides used gave a good weeding effect. Yield components and yields were not affected by different-aged seedlings after application of the herbicides.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.51-55
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• 1979

The effects of vernalization and darkness on flower initiation were reviewed by using naked barley varieties. The dark effects were pronounced on flower induction even at 25$^{\circ}C$. There were no differences in flowering responses among varieties. The effects of vernalization and darkness combined with 25$^{\circ}C$were 100% and 60% respectively which showed a significant difference. When the alternation of darkness with light was taken as first and last the flowering rate was 92 percent. When it was intercalated by light treatments the flowering rate was 91 per cent. Thus the effects of vernalization and darkness seems to differ.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.73-80
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• 1998

This experiment was carried out to investigate the effect of runner development based on production period and to investigate the yield in different cropping type to nursery plant age. In runner development experiment, heating + lighting + $GA_3$ + cluster removal treatment increased the number of runners by 13.1 times higher in spring season than control(heating only) in overwintering mother-plant. Treatment of 20ppm $GA_3$ was the most effective for runner production in autumn. In nursery plant age experiment, 60 days old nursery plants produced more flower cluster than 40 days old ones. This result indicated that the yield potential was so low that overwintering runners would be adaptable for spring or summer cultivation.