• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.21-27
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• 2016

Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV), and Apple stem pitting virus (ASPV) have been known to induce top working disease causing economical damage in apple. Occurrences of these three viruses in pome fruit trees, including apple, have been reported around the world. The transmission of the three viruses was reported by grafting, and there was no report of transmission through mechanical contact, insect vector, or seed except some herbaceous hosts of ASGV. As RNA extraction methods for fruit trees, Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) and multiplex RT-PCR techniques have been improved for reliability and stability, and low titer viruses that could not be detected in the past have become detectable. We studied the seed transmission ability of three apple viruses through apple seedling diagnosis using RT-PCR. Nineteen seeds obtained from commercially grown apple were germinated and two of the resulting plants were ASGV positive. Seven clones of the amplified ASGV coat protein (CP) genes of these isolates were sequenced. Overall sequence identities were 99.84% (nucleotide) and 99.76% (amino acid). Presence of a previously unreported single nucleotide and amino acid variation conserved in all of these clones suggests a possible association with seed transmission of these 'S' isolates. A phylogenetic tree constructed using ASGV CP nucleotide sequences showed that isolate S sequences were grouped with Korean, Chinese, Indian isolates from apple and Indian isolates from kiwi.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.89-93
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• 1985

In order to develop the nutrient material for growing plants, tobacco leaf debris (T.L.D) that is a residual product of cigarette processing was carbonated at about 50% of its weight and neutralized its alkalinity by nitric and phosphoric acid. This material ($T.L.D+3N-HNO_3+1N-H_3PO_4$ (10:1:1), as a consequence, contained 4.1% of nitrogen, 2.1% of phosphte, and 6.6% of potassium in value of about pH 7. It was very effective on seedling growth to apply 1 Kg of nutrient material per 110 1 of bed soil as basic dressing because of containing not only quick-acting nitrate but also slow-releasing organo-nitrogen and sufficient potassium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.1-8
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• 1995

This study was carried out to investigate the effects of floral inhibition of An-gelica gigas NAKAI in the hilly altitude located in the Northern Gyeongbuk Province from Feb. 1992 to Nov. 1994. The results obtained were as follows ： As the cultivated areas are high, rate of bolting was significantly decreased, having high yield, good growth, and medicinal quality. It is considered that the optimal cultivating area was at least above 600m altitude. In the hilly altitude, the more shorten nursery period was, the more decreased rate of bolting was, it results in decreased yield, having no significant differences in contents such as extracts and decursin. In bolting response from temperature treatment of the seedlings, treatment of high temperature was significantly decreased floral induction, but rate of establishment was decreased by decayed root. Bolting rate at different organic resources has more reduced in single fertilization than that of in organic application, but among organic resources, compost of rice straw has the lowest bolting rate. As a result, yield and medicinal qualities at various organic resources were increased in application of organic resources which was no con-siderable tendency among organic resources.

• Research in Plant Disease
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• v.10 no.4
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• pp.337-340
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• 2004

In April of 2003, the gray mold disease caused by Botrytis cinerea was occured in zinnia seedlings grown in greenhouse at Gyeongsangnam-do Agricultural Research and Extension Services, and farmer's nursery. The symptoms of infected plants were started with water-soaking lesions in flower bud, leaves and stems. The lesions gradually expanded and infected plants became withered and discolored to gray or dark from the tip. The conidia and mycelia of the pathogen were appeared on flowers, leaves and stem. The conidia were gray, 1-celled, mostly ellipsoid or ovoid in shape and were 5${\sim}$16 ${\times}$ 4${\sim}$8 ${\mu}m$ in size. Conidiophores were 12${\sim}$28 ${\mu}m$ in size. The pathogenic fungi formed sclerotia abundantly on potato dextrose agar. The optimum temperature for sclerotial formation was $20^{\circ}C$. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Botrytis cinerea Persoon: Fries based on mycological characteristics. This is the first report on gray mold of Zinnia elegans caused by Botrytis cinerea in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.290-295
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• 2002

Fertilizer granulation test was carried out by a small pan granulator. A premixture composed of SOP 60%, urea 22% and RP powder 18% was rolled in the pan granulator while 10% phosphoric acid solution(binder) was sprayed on the rolling powder bed. Granules were developed very fast along with a little amount of binder. Hardness, brittle ratio in water and hygroscopicity of granules were improved enough to evaluate physical properties of the fertilizer. Growth responses of tobacco plant to the fertilizer were investigated at seedling and flowering stage by pot experiment under plastic film roof. Seedlings showed poor growth at nursery pot cell. In virgin soil with deficient available phosphate tobacco plant showed poor growth until budding and flowering stage but good growth in tillage soil with high cumulative phosphate.

• Journal of Forest and Environmental Science
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• v.33 no.3
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• pp.226-232
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• 2017

Dhup (Canarium resiniferum) is an economically and aesthetically important rare native tree species of Bangladesh. In natural condition 78.5-98.7% seeds do not germinate due to inhibition by hard seed coat, seed predation and unfavorable environmental conditions. A study was conducted in the Seed Research Laboratory and nursery of Institute of Forestry and Environmental Sciences, Chittagong University, Bangladesh in 2013 to find out appropriate pre-sowing treatments for maximizing germination and initial seedling growth. Eleven pre-sowing treatments were provided in both the seeds sown in polybags and seeds sown in propagator house. Results revealed that, germination started at first (after 20 days of seed sown) in seeds immersed in water at room temperature for 24 hours and germination completed within 38 days. Significantly higher (p<0.05) germination percentage (33%), germination energy (16.7%), plant percent (33%) and germination value (0.4) was found with seeds immersed in water at room temperature for 24 hours. Seedling height measured at three, four and five months after the seed germination in case of seeds treated by immersion in water for 24 hours was also greater than others. Therefore, pre-sowing treatment by immersion in water at room temperature for 24 hours was more effective in germination and production of quality vigor seedlings of Dhup.

• 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.

• Research in Plant Disease
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• v.17 no.2
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• pp.228-231
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• 2011

Since 2008, a new leaf spot disease has been found in loquat tree (Eriobotrya japonica) at a nursery station in Goheung, Korea. Above 50% of the seedlings developed the spot symptoms on the leaves. The infected plants were generally reduced in the seedling vigour and early defoliation was occurred. The infected leaves developed grayish lesion with dark reddish brown margin. The pathogen developed round to ellipsoidal acervuli on the lesion. Based on morphological characteristics of the pathogen, the fungus was identified as Entomosporium mespili. The cultured pathogen successfully reproduced the same disease symptom on the leaves of loquat tree and found to be E. mespili. A monoconidial culture was deposited in Korean Agricultural Culture Collection (KACC 44727). This is the first report of E. mespili causing leaf spot of loquat tree in Korea.

• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.55-62
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• 2010

The study was conducted to investigate effects of different organic fertilizers on 'Niitaka' pear tree performances in a controlled greenhouse. The four 'Niitaka' pear seedling trees per treatment were grown in a greenhouse for 6 months. Each pot was filled with control, rice bran (RB), coffee bran compost (CBC), and the mixture (RCC) of RB + CBC + chitin incubated compost (CIC). Each pot was filled with 1:1:1 (v/v/v) of soil : sand : fertilizer, and control, RB, CBC, CIC, and RCC were applied as treatments. Root fresh weights and root activities were increased by all the organic fertilizers, especially by RCC. RCC treated trees had the highest tree height and thickest tree trunk, and all organic fertilized trees showed increased tree growth compared to the control. The more diseased and damaged degrees on the leaf by spider mites increased leaf falling rates on all the treatments. The reduced diseased and healthy leaves were found on RCC treated trees that had better tree performance. Also, all the organic fertilized trees seemed to prevent the occurrence of disease in the leaf. Therefore, the organic fertilizer applications could be a good strategy to obtain better tree performance and maintain healthy seedlings in the nursery market or young organic pear orchard.

• Korean Journal of Medicinal Crop Science
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• v.26 no.3
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• pp.205-213
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• 2018

Background: Since the revised Ginseng Industrial Act was passed, ginseng sprouts have become a new medicinal vegetable for which there is high consumer demand. However, the existing amount of research and data on ginseng production has not kept pace with this changed reality. Methods and Results: In this study we analyzed the changes in the amounts of ginsenosides in different parts of growing ginseng sprouts during the period from when organic seedlings were planted in nursery soil until 8 weeks of cultivation had elapsed, which was when the leaves hardened. In the leaves, ginsenoside content increased 1.62 times with the panaxadiol (PD) system and 1.31 - 1.56 times with the panaxatriol (PT) system from 7 to 56 days after transplantation. During the same period, the total ginsenoside content of the stems decreased by 0.66 - 0.91 times, and those of the roots increased until the $21^{st}$ day, and then underwent steep declines. The effect of fermented press cake extract (FPCE) and tap water (TP) on the total amount of ginsenoside per plant were similar, and could be represented with the equations $y=1.4330+0.2262x-0.0008x^2$ and $y=0.9555+0.2997x-0.0031x^2$ in which y = ginsenoside content x = amount of and on the total amounts of FPCE or TP, respectively after 26.4 days, however, the difference between ginsenoside content with FPCE and TP widened. Conclusions: These results suggested that the amounts of ginsenosides in different parts of ginseng varied with the cultivation period and nutrient supply. These findings also provide fundamental data on the distribution of ginsenosides among plant parts for 2-year-old ginseng plants in the early-growth stage.