• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.427-434
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• 2014

This study aimed to investigate the effects of pre-harvest sprouting (PHS)-damaged grains of rice on seed viability, germination percentage and seedling emergence rate. As comparing the seed lots of same cultivar 'Hopum' with different PHS percentages, seed lot with 8% PHS (high PHS percentage) showed 30% lower germination than that with 1% PHS (low PHS percentage). The difference of seedling emergence rate and seed viability percentages between the two seed lots was consistent with that of germination percentage. PHS-damaged brown rice was observed protruded embryo, discolored endosperm and fungi infected grains. PHS grains were classified into two groups, PHS-I showing endosperm discoloration in one third of a grain and PHS-II in more than half of a grain. The seed lot with high PHS percentage had much more PHS-II grains than that of low PHS percentage. PHS-II grains showed remarkably lower germination percentage than PHS-I grains and got severely moldy during germination test. In laboratory experiment, morphological changes and re-germination ability of seeds which dried after germination by soaking were tested. Sprouted seeds of 3mm shoot length showed half discolored endosperm and had a strong resemblance with PHS-II grains. Re-germination percentage of 3mm sprouted seeds sharply decreased than 2 mm sprouted seeds. Sprouted seeds which were treated for accelerated-aging (AA) for 24hr at $45^{\circ}C$ were significantly reduced in re-germination percentage compared to that of non-AA-treated sprouted seeds. These results indicate that PHS with over 3mm shoot length can severely damage not only grain appearance but also seed viability, germination percentage and seedling emergence rate. Therefore, we conclude that larger difference of germination percentage or seedling emergence rate between seed lots having smaller difference of PHS percentage might be caused by accelerated seed deterioration in PHS-damaged rice grains.

• Journal of Forest and Environmental Science
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• v.35 no.2
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• pp.69-77
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• 2019

Pterocarpus erinaceus is a multipurpose tree species indigenous to semi-arid and Guinean-savanna woodlands of Africa. Natural regeneration on the savanna is being hampered by higher fire frequencies and other land use changes. Simultaneously, demand for timber from the species on the international market is on the rise, raising conservation concerns. To ensure sustainability, good quality seeds, sources of which have not received much research focus, are needed for afforestation. This study investigated how seed quality, germinability and initial seedling growth of P. erinaceus might be influenced by land-use type, mother tree size as well as source and timing of fruit harvest, using both correlational and experimental approaches. The results showed that up to 94.6% of all harvested fruits contained seeds, with no differences found between fruits harvested from cultivated and non-cultivated lands. Percentage of (sound) unblemished seeds was found to be higher for fruits harvested early March (47.3%) than fruits from late April (39.5%). Percentage sound seeds was 41.4% for dispersed fruits (i.e. detached fruits picked from under mother trees) which was not found to differ from undispersed fruits (i.e. fruits harvested while still attached to mother trees) at 45.5%. Also, the influence of fruit harvest time was not found to be different for dispersed and undispersed fruits. Correlations between seed set (proportion of fruits containing seeds) and mother tree size (both tree height and DBH) were found to be very low and non-significant for both dispersed and undispersed fruits. Across mother trees, mean emergence percent was 79.7%, and mean seedling height at three weeks following emergence was 5.32 cm. Both emergence percentage and seedling height were not found to differ among mother trees, but seeds from dispersed fruits had a higher emergence percent (85%) than seeds from undispersed fruits (74%). Implications of findings are discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.75-79
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• 2003

Oral supplementation of zinc chloride to silkworm larvae in different concentrations (30, 60 and 90 ${\mu}g$/ml) to the fourth and fifth instar resulted in a significant increase in commercial traits, like larval weight, silk gland weight, cocooning percentage in lower concentrartion (30 ${\mu}g$) treated group. The female cocoon weight, shell weight and its ratio were significantly increased in 30 and 60 ${\mu}g$ treated groups, male cocoon weight, and shell weight in 30 ${\mu}g$ treated group and its ratio in 60 and 90 ${\mu}g$ treated groups, filament length, weight and moth emergence percentage in all the treated groups and egg productivity in 90 ${\mu}g$ treated group were increased significantly. The remaining groups did not show any significant changes compared with that of carrier control.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.1
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• pp.19-24
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• 2005

Nutrition is very essential for growth, development and reproduction. The quantitative impetus of nutritional factor on adult characters and reproductive fitness was studied in Antheraea mylitta by providing fresh leaves of Terminalia tomentosa for 1 to 4 times a day to $5^{th}$ instar larvae. All the characters have improved on giving fresh diet more times over the single diet. The adult weight has strong effect on the reproductive potential i.e., female pupa and moth weight, survivability, pupation rate, emergence percentage, fecundity, fertility, egg weight and hatched out larval weight. The improvement recorded to the tune of $70\%,\;77.1\%,\;115.4\%,\;36.7\%,\;45.9\%\;and\;218.3\%$ in larval weight gain, survivability, pupation rate, female pupa weight, moth weight and fecundity respectively when fresh diets were provided 4 times a day against single diet. The adult emergence percentage has increased from $66.4\%\;to\;96.2\%$ and fertility rose from $52.2\%\;to\;93.6\%$. The weight of eggs and the larvae hatched out of it also found to be significantly higher in 4 diets a day condition. The study revealed that optimization of fresh diet frequency should be maintained to obtain higher egg production and fertility in order to get vigorous larvae to continue the generation.

• Journal of Sericultural and Entomological Science
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• v.38 no.2
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• pp.130-137
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• 1996

Effect of topical application with 5, 10 and 15${\mu}$g/ml thyroxine on the pre-cocoon, cocoon, postcocoon and silk improvement were studied in bivoltine silkworm NB18 breed of B. mori L. Thyroxine was applied independently on alternate days to silkworm of IV and V instar larvae. The treatment of all different concentrations resulted in a significant increase in commercial characters like larval weight, silkgland weight, cocooning percentage, female cocoon weight and its shell weight and male cocoon shell weight and its ratio, cocoon dimension, length of the filament and its weight and oviposition. However, there was no significant change in larvel weight in 5${\mu}$g/ml treated group and larval duration was significantly decrease. But moth emergence percentage and hatching percentage did not show any significant change when compared with that of carrier control.

• Korean journal of applied entomology
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• v.17 no.2 s.35
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• pp.105-113
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• 1978

The experiments were carried out both at $#160$, Anyang Ri, Anyang, Kyung-gi Do, as a field plot and at college of Agriculture, Seoul National University, Suweon as laboratory plot, in order to unnorive the types of traps for collection of adult pine gall midge (Thecodiplosis japonensis Uchida) And the conclusions of the experimental results were as follows. (1) The seasonal fluctuation of the adult emergence of the PGM continued from middle pa.1 of the May to late part of the August. And the peak of the adult emergence showed variation in the number of PGM captured, according to the types of traps used, such as May 2g-june 2, by standard Cage, June 3-June7 by Funnel-A t.sp and June 8-June 12 by Suction-Trap. (2) The Percentage of the emergence in the laboratory experimental Plot were $41.06\%$ of Funnel-A traps used. f 3) The Suction-Trap was considered as effective instrument of. collection of adult PGM especially in the seasons of both earlier and later parts of the adult emergence, which is the population density is extremelty low. (4) It is considered that the recommendable instruments were Funnel-A type of trap and suction-Trap according to the experimental results obtained.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.343-348
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• 2014

We developed a simple model to predict emergence time and emergence rate of southern type garlic using the daily mean temperature. Emergence rate of garlic was decreased and emergence time was delayed on higher temperature than optimum temperature of $12.7^{\circ}C$. In the model, firstly daily emergence rate was calculated using a beta function to input daily mean temperature, then the percentage of garlic emergence was calculated using a nonlinear model with accumulated emergence rate. The model was good to describe the experimental data of growth cabinet. Also it can explain well the experimental data using temperature gradient tunnel, designed for verification of model performance. But there are 5 days of deviation between estimated and measured time of garlic emergence on the field experiment. More research is needed to develop an advanced model considering other factors, such as soil moisture.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.38-42
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• 2001

This study was conducted to stable direct sowing cultivation with seedling growth promotion by plant growth regulator treatment in onion seed(Allium cepa L.) The emergence percentage of soaked seed in BA, GA$_3$, and kinetin solution were higher than control seed, and those were 93.0, 94.3, 93.8%, respectively. The plant height was significant elongation in growth regulators treated seed, and those effects were high GA$_3$, kinetin and BA in the order, and the extend were high as increasing the growth regulator solution concentration in GA$_3$ and BA, and that was reverse in kinetin. The No. of leaf was increased in growth regulators treated seed, and the extend were similar among the growth regulators. The No. of root was increased significantly in growth regulators treated seed, and the extend were high in GA$_3$, BA and kinetin in the order.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.121-130
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• 1995

Greenhouse and laboratory studies were conducted to investigate allelopathic potential of some weed species on alfalfa(Medicago sativa L.) germination and seedling growth. In the comparison between top(leaves+stems) and root extracts, top extract exhibited greater allelopathic effects on alfalfa germination than that of root. The various weed species extract differently responded to alfalfa test species, WL-320, in terms of allelopathic effect. Top and root aqueous extracts of lambsquarter(Chenopodium album L.), giant foxtail(Setaria faberii Herrm.), redroot pigweed (Amaranthus retroflexus L.), velvetleaf(Abutilon theophrasti Medic.), crabgrass(Digitaria sanguinalis L.), canada thistle(Cirsium arvense L.) and prostrate knotweed(Polygonium aviculare L.) significantly inhibited germination, seedling length, weight, vigor, and rate of germination of alfalfa. The regression slopes of various top extracts showed that velvetleaf(b=3.69) extracts were the most inhibitory, while large crabgrass(b=2.39) extracts had the least allelopathic effect on alfalfa germination. Germination, seedling length and weight of alfalfa were inversely proportional to the concentration of dried velvetleaf extracts. Also, more of the toxic effects were observed from the dried extracts compared to the fresh extracts. Residue of velvetleaf inhibited significantly alfalfa emergence and survival percentage compared to the control. The emergence and survival percentage of alfalfa were 44%, 57% at 1.0% residue treatment, respectively. When weed residues were mixed with silica sand with incubation time, velvetleaf residue most inhibited alfalfa growth. The degree of inhibition increased as incubation time increased. An incubation for 72h caused the greatest inhibition of alfalfa growth. These results demonstrate the different allelopathic activity of weed species extracts on alfalfa and suggest that weed may affect alfalfa growth and development through the inhibitory effects of allelochemicals present in weed tissue.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.605-616
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• 2023

Scuticociliatosis, caused by the parasitic pathogen Miamiensis avidus, poses a significant threat to olive flounder farms in South Korea. Infected fish suffer from severe systemic infections affecting various organs, with potential secondary bacterial diseases. This study investigated the emergence of different M. avidus serotypes in 20 olive flounder farms on Jeju island, South Korea, from 2015 to 2020. Additionally, we identified Tenacibaculum maritimum as a co-infecting bacteria. Based on serotyping and monitoring data, we developed a trivalent vaccine targeting two serotypes of M. avidus and one strain of T. maritimum. The efficacy of the vaccine was evaluated under laboratory conditions and demonstrated a relative percentage of survival (RPS) of 75%, 80%, and 93% for M. avidus serotype I, M. avidus serotype II and T. maritimum, respectively. Furthermore, successful field trials conducted on four different olive flounder farms resulted in significantly higher survival rates (52%-76% RPS) and weight gains in vaccinated fish. Overall, this study presents an effective vaccine against M. avidus and T. maritimum infections in farmed olive flounder, making a valuable contribution to sustainable aquaculture in South Korea.