• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.7-13
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• 1989

The present study was carried out to get the basic information for clarifying physiological mechanism of breaking dormancy and sprouting in Panax ginseng roots. Changes in Abscisic acid (ABA) content and Gibberellin (GA) activity were investigated in one-year-old root during stratification at 4$^{\circ}C$. 15$^{\circ}C$. and 15$^{\circ}C$ after 60day-treatment at 4$^{\circ}C$. Sprouting rate at 15$^{\circ}C$ was 35％ in 30days storage at 4$^{\circ}C$ and 100％ in longer than 60days, but there was no sprout in both the constant treatment at 4$^{\circ}C$ or 15$^{\circ}C$ regardless of the treatment period. The longer the period of low temperature treatment. number of days to the first and 50％ sprouting was shortened, and number of days to 50％ from first sprouting was also shortened. ABA content in the upper part of root(contained bud) was gradually increased at both 4$^{\circ}C$ and 15$^{\circ}C$ as the treatment period was extended. and the degree of increase was higher at 15$^{\circ}C$. In the lower part. it showed a slight increase at 15$^{\circ}C$. while showed little change at 4$^{\circ}C$ throughout the treatment period. In the 15$^{\circ}C$ treatment after 60days at 4$^{\circ}C$, it was greatly increased in the upper part. while rather slightly decreased in the lower part of root. GA activity in the upper part was gradually decreased at both 4$^{\circ}C$ and 15$^{\circ}C$, and the degree of decrease was higher at 15$^{\circ}C$. In the lower part. it was similar tendency to those in the upper part. In the 15$^{\circ}C$ treatment after 60days at 4$^{\circ}C$. it was remarkably increased in both the upper and lower part. The increase was great in the low Rf region, while the decrease appeared relatively in the high Rf region compared to those of 60day-treatment at 4$^{\circ}C$. The above results indicated that the breaking dormancy and sprouting of bud were closely associated with the degree of GA activities in response to temperature condition .during stratification rather than the direct effect associated with the changes in ABA content.

• Resources Recycling
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• v.31 no.6
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• pp.44-51
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• 2022

In the steelmaking process using an electric arc furnace (EAF), light-burnt dolomite, which is a flux containing MgO, is used to protect refractory materials and improve desulfurization ability. Furthermore, a recarburizing agent is added to reduce energy consumption via slag foaming and to induce the deoxidation effect. Herein, a waste MgO-C based refractory material was used to achieve the aforementioned effects economically. The waste MgO-C refractory materials contain a significant amount of MgO and graphite components; however, most of these materials are currently discarded instead of being recycled. The mass recycling of waste MgO-C refractory materials would be achievable if their applicability as a flux for steelmaking is proven. Therefore, experiments were performed using a target composition range similar to the commercial EAF slag composition. A pre-melted base slag was prepared by mixing SiO₂, Al₂O₃, and FeO in an alumina crucible and heating at 1450℃ for 1 h or more. Subsequently, a mixed flux #2 (a mixture of light-burnt dolomite, waste MgO-C based refractory material, and limestone) was added to the prepared pre-melted base slag and a melting reaction test was performed. Injecting the pre-melted base slag with the flux facilitates the formation of the target EAF slag. These results were compared with that of mixed flux #1 (a mixture of light-burnt dolomite and limestone), which is a conventional steelmaking flux, and the possibility of replacement was evaluated. To obtain a reliable evaluation, characterization techniques like X-ray diffraction (XRD) analysis and X-ray fluorescence (XRF) spectrometry were used, and slag foam height, slag basicity, and Fe recovery were calculated.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.41-46
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• 2022

To investigate the domestic seed production potential of Italian ryegrass, it was sown in autumn in the southern region and harvested in the spring of the following year to investigate the productivity and quality of seeds and straw. Italian ryegrass (Lolium multiflorum Lam.) 'GreenCall' variety was sown in Jinju, Gyeongnam in the fall of 2020 with three seeding rates (20, 30 and 40 kg/ha). The experiment was arranged consisted of a randomized block design with three replications. The ryegrass was sown on October 17, 2020, and the harvest was on May 31, about 60 days from the heading stage. The heading stage of Italian ryegrass was April 28, and there was no difference among treatments. Plant height was significantly shorter in the 40 kg/ha seeding treatment group, and there was no significant difference in the remaining treatments. The resistance of lodging, disease, and cold did not show significant differences among treatments. Spike length and number of seeds per spike were highest at 20 kg/ha seeding amount, and there was no difference in the remaining treatments. The seed yield was the highest at 1,956 kg/ha in the 20 kg/ha seeding rate, and there was no difference in the 30 and 40 kg/ha seeding rates. The dry matter content of seeds and straws was 45.60 and 41.83% on average, and there was no significant difference among treatments. The amount of remaining straw after seed harvesting was found to be 7,689 kg/ha on average on a dry basis, and it was high in the 40 kg/ha sowing area, but there was no significant difference among treatments. According to the above results, it was found that it is most advantageous to sow at 20 kg/ha when producing Italian ryegrass seeds through autumn sowing in the southern region.

• Journal of agriculture & life science
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• v.50 no.2
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• pp.73-82
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• 2016

Best drought tolerance index was determined through statistics analysis and growth appearance of drought tolerant plants was determined by cultivation in pot and sloping land. For determination of best drought tolerant indicators, RD(Resistant dry days), LD(Leaf area), UTR(Unit transpiration), RWC(Relative water content), RWL(Relative water loss), LA(Leaf area), SN(Stoma unmber) and SA(Stoma area) were carried out by correlation and PCA analysis. RWL and UTR were affected on plant drought tolerance according to comparison among six indices for resistant dry days. The PCs axes separated SA, LA, RD and RWC and SN. UTR was negatively correlated with SA, RWL were also negatively correlated with RWC and SN. RWL and UTR were proved best selection indicator for the selection of drought tolerant species. Ulmus parvifolia, Bidens bipinnata, Patrinia villosa, Kummerowia striata, Arundinella hirta, Artemisia gmelini etc. were selected drought tolerant plants. Shoot growth appearance of drought resistant plants was differed pot and sloping land. Shoot growth and leaf number was no significant differences between the pot and sloping land. However, root growth of drought tolerant plants was all the difference between two cultivation. T/R ratio of drought tolerant plants was also found a big difference. T/R ratio of drought tolerant plants in sloping land was lower than that of pot. These results will be served efficiently plant breeding.

• Korean Journal of Poultry Science
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• v.50 no.2
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• pp.91-99
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• 2023

This study aimed to develop a high-productivity breed of Korean native Samgye chicken. We evaluated the production performance of six Korean native chicken combinations (KNC-SCYC, SCYD, SDYC, SDYD, SYYC, SYYD) and GSP-Hanhyup Korean native chickens, with Baeksemi chickens used as a control group. The performance test was conducted from hatching to 7 weeks of age on 756 chickens, and we measured survival rate, body weight, shank length, feed utility, and carcass yield. The overall survival rate was nearly 100% for all strains. However, body weight showed significant differences between strains at all ages (P<0.01), with Baeksemi weighing 863.8±76.9 g, GSP-Hanhyup weighing 804.7±72.5 g, and KNC-combinations weighing 543.0±61.8 g at 5 weeks of age. The duration needed to reach 850 g was estimated to be 34.5 days for Baeksemi, 37.5 days for GSP-Hanhyup, and 45.8-48.8 days for KNC-combinations. Carcass yield percentage was highest for KNC-SYYD combination at 63.3%, followed by Baeksemi at 60.4%, and GSP-Hanhyup at 56.1%. Shank length at 850 g body weight was 7.6 cm for KNC-SYYD combination, 7.8 cm for Baeksemi, and 8.0 cm for GSP-Hanhyup. The feed conversion ratio at 850 g body weight was 1.81 for Baeksemi, 2.17 for GSP-Hanhyup, and 2.27 for KNC-SCYC combination. Our results suggest that the KNC-SYYD combination and GSP-Hanhyup breed have the potential to be used in Samgye production due to their moderate growth performance, higher carcass yield, and shorter shank length, despite their lower growth productivity and feed efficiency when compared to Baeksemi.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.170-175
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• 2023

In this study, the effect of MnSO₄ on the insecticidal crystal (IC) produced by Bacillus thuringiensis for a rapid detection medium was analyzed. The strains used included one B. thuringiensis reference (KCTC 1511) and nine wild-type strains. The IC in B. thuringiensis was detected following the method published by the Ministry of Food and Drug Safety in Korea. In the nutrient agar to which 0.005% MnSO₄ was added, IC was observed on two of the three plates after 48 hours of incubation and on all three plates after 120 hours. In AK agar, IC was observed on one and two of the three plates after 48 and 96 hours of incubation, respectively. These results indicated that 0.005% MnSO₄ nutrient agar is more appropriate than AK agar for production of IC in B. thuringiensis. The effect of various MnSO₄ concentrations on IC production was studied after 24 hours of incubation. IC was produced on 1 of the 10 plates with 0.000% MnSO₄ nutrient agar, 2 of the 10 plates with 0.001% MnSO₄ nutrient agar, and 3 of the 10 plates with 0.002% MnSO₄ nutrient agar. IC was not observed for the other nutrient agars containing 0.003%-0.009% MnSO₄. These results indicated that nutrient agar with 0.002% MnSO₄ led to the most rapid production of IC by B. thuringiensis after 24 hours of incubation. However, the conditions for IC production by B. thuringiensis depended on the incubation conditions and strain activity. Therefore, further studies are needed to verify the effects of 0.002% MnSO₄ on the production of IC by various Bacillus thuringiensis strains.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.241-249
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• 2023

Following the Animal genetic resource for food and agriculture (AnGR) is considered as an independent resource for the possessing country, ensuring the sovereignty of AnGR is important. The present study investigated the growth and egg production performance of six breed enrolled in DAD-IS for the purpose of securing scientific data on AnGR in Korea. A total of 323 chickens (female 181, male 142) were used in this study, with the following six breeds: Korean Leghorn (LEG), Gyeongbuk Araucana (ARA), Korean native chicken (KNC), Korean Ogye (Ogye), Hyunindak (HIL), Heongseongyakdak (HYD). The body weight of male ARA from hatching to 32 weeks of age was the highest among the breeds, and LEG and Ogye were relatively lower (P<0.0001, excluded body weight data of HYD). The body weight of female ARA was the highest and HYD was significantly the lowest among the female chicken breeds (P<0.0001). The laying percentage was the highest in LEG and was the lowest in HYD among the breeds (P<0.0001). The average egg weight from 20 to 40 weeks of age was the highest in ARA, followed by LEG and was the lowest in Ogye (P<0.0001), and the adapted breed including LEG and ARA was higher than indigenous breed (P<0.05). Egg mass production was the highest in Korean Leghorn. Collectively, these results show that ARA has the best growth ability, and LEG has the best egg production performance among the used breeds. This suggests that the adapted breed with high commercial performance is important AnGR in Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.2
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• pp.64-70
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• 2024

The experiment was conducted to determine the changes in seed productivity of Italian ryegrass (Lolium multiflorum Lam.) according to nitrogen fertilization levels in the southern region of Korea. Italian ryegrass (IRG) variety 'Green Call' was sown in the fall of 2021 in Jinju, Gyeongsangnam-do. The experiment consisted of three nitrogen fertilizer levels (100, 120, and 140 N kg/ha) with three replications using a randomized complete block design. Harvesting was done approximately 30 days after heading on May 18th. There was no difference in heading date among treatments, which occurred on April 18th. The longest IRG was observed in the 140 N kg/ha treatment, but there was no significant difference. No significant differences were observed in lodging, disease resistance, and cold tolerance among treatments, but lodging was severe in all treatments. The length of the spike averaged 44.95 cm, with no difference among treatments, and the number of seeds per spike was highest in the 120 N kg/ha treatment. Seed yield increased with increasing nitrogen fertilizer levels, averaging 3,707 kg/ha (as-fed basis). DM content of seed and straw averaged 76.95% and 62.19%, respectively, with no significant differences among treatments. The remaining straw after harvesting averaged 6,525 kg/ha on a dry matter basis, with the highest value observed in the 140 N kg/ha treatment. Overall, considering the results, the optimal nitrogen fertilizer application rate for seed production of Italian ryegrass in the southern region when sown in autumn was found to be 120 N kg/ha.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.2
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• pp.118-126
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• 2024

This study was conducted in Cheonan, the middle region of South Korea, to evaluate the forage characteristics of six medium maturing Italian ryegrass varieties: 'Kowinmaster', 'IR 601', 'IR 602', 'IR 603', 'IR 604' and 'IR 605'. In growth characteristics, 'Kowinmaster' exhibited the earliest heading date on April 30, while 'IR 601' exhibited the latest on May 17. 'IR 601' exhibited the highest lodging resistance, and all varieties demonstrated excellent disease resistance, waterlogging tolerance, and cold tolerance. 'IR 603', 'IR 604', and 'IR 605' demonstrated above-average plant length, with 'IR 604' reaching the longest at 114.8 cm. In productivity, 'IR 602' and 'IR 605' produced the highest total dry matter yield, each exceeding 12,800 kg/ha. Regarding feed values, 'Kowinmaster' recorded the highest RFV and TDN at 119.18 and 66.07%, respectively, with 'IR 605' exhibiting the second highest. 'IR 604' and 'IR 601' demonstrated crude protein concentrations over 9%, with 'IR 604' exhibiting the highest at 9.74%. Analysis of monosaccharide content in Italian ryegrass revealed that 'IR 605' exhibited the highest glucose and fructose content at 23.35 g/kg and 50.70 g/kg, respectively. In summary, 'IR 602' exhibited the highest productivity, 'Kowinmaster' recorded the highest feed value, and 'IR 605' exhibited the highest glucose and fructose content. Therefore, 'IR 605' is considered the most outstanding variety due to its superior productivity, second highest feed value, and significant monosaccharide content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.407-428
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• 1991

The eastern coastal area having variability of climate is located within Taebaek mountain range and the east coast of Korea. It is therefore ease to cause the wind damages in paddy field during rice growing season. The wind damages to rice plant in this area were mainly caused by the Fohn wind (dry and hot wind) blowing over the Taebaek mountain range and the cold humid wind from the coast. The dry wind cause such as the white head, broken leaves, cut-leaves, dried leaves, shattering of grain, glume discolouration and lodging, On the other hand the cold humid wind derived from Ootsuku air mass in summer cause such symptom as the poor rice growth, degeneration of rachis brenches and poor ripening. To minimize the wind damages and utilize as a preparatory data for wind injury of rice in future, several experiments such as the selection of wind resistant variety to wind damage, determination of optimum transplanting date, improvement of fertilizer application methods, improvement of soils and effect of wind break net were carried out for 8 years from 1982 to 1989 in the eastern coastal area. The results obtained are summarized as follows. 1. According to available statisical data from Korean meteorological services (1954-1989) it is apperent that cold humid winds frequently cause damage to rice fields from August 10th to September 10th, it is therefore advisable to plan rice cultivation in such a way that the heading date should not be later than August 10th. 2. During the rice production season, two winds cause severe damage to the rice fields in eastern coastal area of Korea. One is the Fohn winds blowing over the Taebaek mountain range and the other is the cold humid wind form the coast. The frequency of occurrence of each wind was 25%. 3. To avoid damage caused by typhoon winds three different varieties of rice were planted at various areas. 4. In the eastern coastal area of Korea, the optimum ripening temperature for rice was about 22.2$^{\circ}C$ and the optimum heading date wad August 10th. The optimum transplanting time for the earily maturity variety was June 10th., medium maturity variety was May 20th and that of late maturity was May 10th by means of growing days degree (GDD) from transplanting date to heading date. 5.38% of this coastal area is sandy loamy soil while 28% is high humus soil. These soil types are very poor for rice cultivation. In this coastal area, the water table is high, the drainage is poor and the water temperature is low. The low water temperature makes it difficult for urea to dissolve, as a result rice growth was delayed, and the rice plant became sterile. But over application of urea resulted in blast disease in rice plants. It is therefore advise that Ammonium sulphate is used in this area instead of urea. 6. The low temperature of the soil inhibits activities of microorganism for phosphorus utilization so the rice plant could not easily absorb the phosphorus in the soil. Therefore phosphorus should be applied in splits from transplanting to panicle initiation rather than based application. 7. Wind damage was severe in the sandy loamy soil as compared to clay soils. With the application of silicate. compost and soil from mointain area. the sand loamy soil was improved for rice grain colour and ripening. 8. The use of wind break nets created a mocro-climate such as increased air. soil and water temperature as well as the reduction of wind velocity by 30%. This hastened rice growth, reduced white head and glume discolouration. improved rice quality and increased yield. 9. Two meter high wind break net was used around the rice experimental fields and the top of it. The material was polyethylene sheets. The optimum spacing was 0.5Cm x 0.5Cm. and that of setting up the wind break net was before panicle initiation. With this set up, the field was avoided off th cold humid wind and the Fohn. The yield in the treatment was 20% higher than the control. 10. After typhoon, paddy field was irrigated deeply and water was sprayed to reduce white head, glume discolouration, so rice yield was increased because of increasing ripening ratio and 1, 000 grain weight.