• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.151-156
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• 1986

There are differences in recommendations in the USA as to whether nitrogen fertilizer should be applied when establishing alfalfa (Medicago sativa L). The reason for not applying nitrogen is because some researchers found the addition of nitrogen reduced nodulation of alfalfa plants. A replicated experiment was conducted under controlled environmental conditions at the University of Nevada-Reno, Reno, Nevada, USA, to determine the effects of nitrogen application on seedling growth and nodulation of alfalfa when grown in a cool environment. A sterile sand was used in the growing media to which a complete nutrient solution minus nitrogen was applied volumetrically to each pot daily. Half of the pots received $NH_4NO_3$, at the rate of 11.2 kg/ha, at seeding and two and four weeks after planting, giving a total nitrogen application rate of 33.6 kg/ha. Rhizobia inoculant (R-12) consisted of a mixture of strains 171-15a. 1682c and 80 PI 265 of Rhizobium meliloti. Inoculant was applied to the seeds prior to planting and to the sand media at two and four weeks after seeding. Twenty seeds were planted in pots 14.0 cm in diameter and 11.5 cm deep. Seedlings were thinned after emergence to ten plants per pot. They were grown in a controlled environment chamber with a 16-hour light period. Soil temperatures at 6 cm depth ranged from $5.7^{\circ}C\;to\;21.5^{\circ}C$ and had a daily mean of $16.2^{\circ}C$ Plants were harvested at weekly intervals for seven weeks at which time root, shoot and total length, dry weight, volume and number of nodules per plant were determined. Root, shoot and total length were not affected by nitrogen fertilizer. However, application of nitrogen increased the size of the seedlings as determined by dry weight and volume when compared to plants which were not fertilized. This indicates that rhizobia did not fix enough atmospheric nitrogen to promote good growth. Nitrogen application resulted in significantly more nodules per plant. The effect of nitrogen fertilizer became more apparent as the plant became older. Results of this experiment show there are benefits from applying nitrogen at a low rate when establishing alfalfa under a cool environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.221-226
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• 1981

The seedlings of the scallop, Patinopecten yessoensis, which were collected in April 1980, April 1981 and May 1981, and the grown-up scallops collected in the sea bottom in November 1979, were reared by hanging method up to the July 1981. The growth of the seedlings collected in April 1980 was greatly affected by the time of the seedling collection, manipulation of the net cage, density in the net cage and the annual water temperature fluctuation. The scallops reared from the spat collected in April 1980 reached the sizes of 0.33 mm, 1.23 mm, 29.34 mm and 59.59 mm in shell length in 40,75, 285 and 450 days respectively. Since then, growth rate was determined as follows based on the age estimated by the year rings on the shell:84.96mm in 19 months, 99.3mm in 31, 112.3mm in 37 and 113.64mm in 43 months. The meat and the adductor muscle weight increased with the shell length. The meat weight roached about 15g when the shell length was 60-70mm and about 94.13 g when 130-140mm, and the adductor muscle weight reached about 4.89 g when the shell length was 60-70 mm and about 39.59g when 120-130 mm. But the growths of the meat and the adductor muscle weight were in stagnancy after scallops reached 125 mm in shell length.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.300-312
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• 2020

The growing stocks of young forests that are less than10 years of age have been excluded from the Korean forest resource statistics, despite the existence of standing trees; however, sustainable forest management and carbon removals in the forestry section require complete information regarding forest resources. This study developed a method to estimate the growing stocks for young forests from National Forest Inventory (NFI) data. After reviewing previous research on growth characteristics for young forests, we conducted stem analysis of major species, and examined stand characteristics by site index, based on real yield tables. Our statistical analysis results showed that there were few standing trees with diameters at breast height (DBH) above 6 cm in young stands, and that it would have taken 12 years, on average, to reach 6 cm DBH. This suggests that mean tree height by diameter should be assessed at the root, in order to assess growing stocks for young stands through the NFI. Moreover, the database system should be improved to differentiate tree species, since diverse shrubs, including trees, have been surveyed.

• Korean Journal of Environment and Ecology
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• v.34 no.1
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• pp.18-26
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• 2020

Echinosophora koreensis (Nakai) Nakai an endemic plant with limited distribution in some parts of the Korean Peninsula, is designated as "Endangered" species on the IUCN Red List. The species is under the threat of deterioration in nature due to various environmental changes causing loss of natural habitats. We investigated the distribution pattern and population structure of E. koreensis to serve as a basic reference for identifying the dynamics and persistence of natural populations of this species in the future. To determine the characteristics of the E. koreensis population, we laid two to three large plots sized 20m×30m on the ridgeline as the reference in Yanggu, Chuncheon, and Hongcheon and laid four to seven small quadrats sized 1m×1m on the transect. A total of 530 plots were laid, 10 each at 2m interval, to measure the number of the stems, the number of fruiting, height, and other factors. The collected distribution information was compared with the existing IUCN assessed categories by applying IUCN Red List ver 3.1 Criteria B. The average population density of the three surveyed areas was 3.47 stem/㎡; the density of each area was 3.95 stems/㎡ in Yanggu, 3.37 stems/㎡ in Chuncheon, and 2.87 stems/㎡ in Hongcheon. The number of fruiting per stem was 0.0038, indicating only 7 fruits out of 1,837 stems and that vegetative reproduction is likely to be more dominant than sexual reproduction. The distribution tendency of population density in the small plots in three surveyed areas showed that the density of E. koreensis tended to decrease toward the center of the forest with low crown openness and around the mountain ridge with high crown openness. It indicated that the quantity of light could be a very important factor for the growth of individuals of this species. The analysis of the heights of individuals present in the surveyed plots showed a range of 2.3 ~ 68.5cm and an average of 20.1cm. An analysis on the stage-structure of the E. koreensis population based on the sieve height found that the appearance frequency decreased with increasing height above 15 ~ 20cm and that the percentage of individuals lower than 10cm, which were presumed to be seedlings, was severely low, indicating a necessity of study on the population sustainability based on the monitored data. The occupied area calculated with the collected species distribution information was 200㎢, indicating the EN category according to the IUCN Red List Reference B.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.182-188
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• 2011

This research was conducted to evaluate the effect of supplemental light-emitting diode (LED) light on growth characteristics and phytochemical content of pepper (Capsicum annuum L.) seedling using LED blue (470 nm, B), red (660 nm, R), blue + red (BR), far red (740 nm, FR) and UV-B (300 nm) light treatment, and without artificial light. Photon flux of LED light was 49, 16, 40, 5.0 and $0.82{\mu}mol\;m^{-2}s^{-1}$ for B, R, BR, FR, and UV-B light, respectively, during experiment. Supplemental LED light duration was $16hr\;day^{-1}$ and UV-B light duration was 10 min. per day after sunset up to 15 days (12 days after germination) of plants age. In our research, growth characteristics and phytochemical content of pepper seedlings were greatly influenced by supplemental LED light compare to control treatment. Red light increased the number of leaves, number of nodes, leaf width and plant fresh weight by 34%, 27%, 50% and 40%, respectively. Blue light increased the leaf length by 13%, and stem length and length of inter node were increased by 17% and 34%, respectively under grown far red light. After 15 days of light treatments phytochemical concentrations of pepper plants were significantly changed. Blue light enhanced the total anthocyanin and chlorophyll concentration by 6 times and 2 times, respectively. Red light increased the total phenolic compound at least two folds meanwhile far red light reduced the ascorbic acid and antioxidant activity 31% and 66%, respectively compared to control treatment.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.148-154
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• 1994

As a vegetative propagation method for ash species, which is a dioecism and a long cycle of fructification, cut-stem was soaked in water to induce adventitious sprouts, and 2-year-old ash seedling was cut in a nursery to induce adventitious sprouts. We obtained the 1,019 adventitious sprouts from branches of 101 plus trees througout the country. The mean ortet-age is 48. There is not a correlation between ortet ages and production of adventitious sprouts. These sprouts were placed in a cutting bed for rooting. Root ability varied with environmental factors of cuttings. The best rooting(87%) resulted from cutting performed in a vinyl-plastic greenhouse. Rooting was better on perlite+peat moss(2 : 1) medium than other media tested. The rooting ability was generally higher in 2-year-old ortet than plus tree ortet. In the root development of cuttings the non-container cuttings was better than container cuttings.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.174-189
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• 1983

Experiments were conducted to evaluate the herbicidal characteristics of pyrazolate [4-(2,4-dichloro benzoyl)-1,3-dimethylpyrazol-5-yl-p-toluene-sulphonate] in greenhouse and lowland rice field. Pyrazolate controlled effectively most of annual weeds and such perennial weeds as Sagittaria pygmaea MIQ., Potamogeton distinctus A. BENN, Sagittaria trifolia L., Cyperus serotinus ROTTB, and Scirpus hotarui OHWI., whereas Eleocharis kuroguwai OHWI. was tolerent to pyrazolate. Although pyrazolate was applied at 2 to 10 days after transplanting, there was no difference in weed control The weeding effect was not influenced by percolation, depth of water and soil type. No difference in crop injury of rice was found with various levels of seedling age, transplanting depth, percolation, depth of water, soil type and time of application. When combined with butachlor, the mixture gave the same effect on rice phytotoxicity and weed control as pyrazolate alone did. Pyrazolate moved 1 to 2cm downward in lowland soil regardless of soil type and percolation. The herbicidal activity of pyrazolate persisted in soil for 60 to 90 days, depending on soil type, percolation and presence of soil microorganism.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.228-235
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• 2009

Growth and branch characteristics of 35 half-sib families were surveyed in a seedling seed orchard of Quercus acutissima at ages 10 and 12. The averages of height, DBH (diameter at breast height), branch height, crown width, branch angle and stem straightness at age 12 were 9.96 m, 14.50 cm, 1.04 m, 6.80 m, $18.82^{\circ}$ and 2.58, respectively. Families of 075 and 052 showed superior height growth and 0511 and 0517 were inferior ones. For DBH growth, 075 and 0413 were best families and 0725 and 0511 were inferior families. Pearson's product moment and Spearman's rank correlation coefficients were all positive for all growth traits except branch angle at ages 10 and 12. This result showed that the families with good height and DBH growth were also superior in stem straightness. In ANOVA, there was a highly significant difference among families in height, DBH, cylindric volume and stem straightness. Branch height, crown width and branch angle were also significantly different among families. Family heritability was higher than individual heritability at ages 10 and 12. Height, DBH and stem straightness were under strong genetic control, showing high family heritability. This implies that high genetic gain could be expected by family selection. Expected genetic gain for each trait was estimated based on the family selection. The highest genetic gain was expected for the traits of branch angle, height and DBH because of the large phenotypic standard deviation and the high family heritability. The growth performance and branch characteristics were weighted by the magnitude of genetic variation and heritability. The weighted values were then subjected to estimate family breeding values. This family breeding value would be applied as a criterion in the genetic thinning of the seed orchard.

• Journal of Korean Society of Forest Science
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• v.14 no.1
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• pp.1-20
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• 1972

The trend and achievements of forest genetics research in abroad were investigated through observation tours and reference work and following facts were found to be important aspects which should be adopted in the forest genetics research program in Korea. Because of world wide recognization on the urgency of taking a measure to reserve some areas of the representative forest type on the globe before the extingtion of such forest type as the results of continuous exploitations of the natural forests to meet the timber demand all over the world, it is urgently needed to take a measure to reserve certain areas of natural stand of Pinus koraiensis, Pinus parviflora, Pinus densiflora f. erectra, Abies koreana, Quercus sp., Populus sp., etc. as gene pool to be used for the future program of forest tree improvement. And the genetic studies of those natural forest of economic tree species are also to be performed. 1. Increase of the number of selected tree for breeding purpose. Because of the fact that the number of plus tree at present is too small to carry out selection program for tree improvement, particularly for the formation of source population for recurrent selection of parent trees of the 2nd generation seed orchard it is to be strongly emphasized to increase the number of plus tree by alleviating selection criteria in order to enlarge the population size of plus trees to make the selection program more efficient. 2. Progeny testing More stress should be placed on carrying out progeny testing of selected trees with open pollinated seeds. And particular efforts are to be made for conducting studies on adult/juvenile correlation of important traits with a view to enable to predict adult performances with some traits revealed in juvenile age thus to save time for progeny testing. 3. Genotype-environment interaction Studies on genotype and environment interaction should be conducted in order to elucidate whether the plus trees selected on the good site express their superiority on the poor site or not and how the environment affect the genotype. And the justification of present classification of seed distribution area should be examined. 4. Seed orchard of broad leaf tree species. Due to the difficulty of accurate comparison of growth rate of neighbouring trees of broad leaf tree species in natural stand, it is recommended that for the improvement of broad leaf trees a seedling seed orchard is to be made by roguing the progeny test plantation planted densely with control pollinated seedlings of selected trees. 5. Breeding for insect resistant varieties. In the light of the fact that the resistant characteristics against insect such as pine gall midge (Thiecodiplosis japonensis U. et I.) and pine bark beetle (Myelophilus pinipera L.) are highly correlated with the amount and quality of resin which are known as gene controlled characteristics, breeding for insect resistance should be carried out. 6. Breeding for timber properties. With the tree species for pulp wood in particular, emphasis should be placed upon breeding for high specific gravity of timber. 7. Introduction of Cryptomeria and Japanese Cypress In the light of the fact that the major clones of Cryptomeria are originated from Yoshino source and are being planted up to considerably north and high elevation in Japan, those species should be examined on their cold resistance in Korea by planting them in further northern part of the country.