• Korean Journal of Poultry Science
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• v.49 no.3
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• pp.145-156
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• 2022

The effect of paternal telomere length on reproductive performance, relationship between paternal and offspring telomere length, and association between paternal telomere length and offspring production performance were investigated in Korean native chickens. Using 22 paternal chickens and 329 offspring, the paternal reproductive performance such as fertility, embryo mortality, and hatchability, as well as the offspring production performance such as survival rate, body weight, and weight gain were analyzed. Telomere length was analyzed through quantitative fluorescence in situ hybridization using lymphocytes. No significant differences were observed in fertility, embryo mortality, and hatchability between paternal chicken telomere lengths (P<0.05). These results indicate that paternal telomere length had a weak negative correlation with fertility and embryonic death rate but a weak positive correlation with hatchability. The correlation coefficient between paternal telomere length and offspring survival rate was r=0.17 (P>0.05). The group of offspring with long paternal telomeres showed relatively poor growth performance. Moreover, a significant negative correlation was estimated between paternal telomere length and offspring growth performance (P<0.05). The correlation coefficient between paternal and offspring telomere lengths was r=0.075 (P>0.05). In conclusion, there was a weak association between paternal telomere length and reproductive performance, offspring survival rate, and offspring telomere length, respectively. However, paternal telomere length and offspring growth performance showed a negative relationship. Such results could be due to the re-extension of telomere length by telomere reprogramming in the early embryonic stage and the different degree of telomere shortening between individuals with increasing age after birth.

• Korean Journal of Poultry Science
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• v.49 no.3
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• pp.139-144
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• 2022

This study was conducted to investigate the effect of three different photoperiods on growth performance, blood properties, and stress indicators in broiler chicks between 1-7 days after hatching. Two hundred and fifty-two 1-day-old male broiler chicks (57.0±0.12 g) were divided into three treatments, with 4 replicates per treatment and 22 birds per replicate subjected to three different photoperiods of 24L, 22L/2D and 18L/6D. A light-emitting diode bulb served as the light source, with an illuminance of 30 lx. As an experimental diet, a commercial feed based on a corn-soybean meal, with 22% CP and 3,150 kcal/kg ME diet, and water were fed ad libitum. Body weight gain, feed conversion ratio, and liver weight ratio showed a statistically significant difference between the 18L/6D and 24L treatments (P<0.05), but with no significant difference between the 22L/2D treatment and either the 24L or 18L/6D treatment. The breast meat ratio was 5.59% in the 18L/6D treatment group, which was lower than that of other treatment groups (P<0.05). The triglyceride levels were highest (P<0.05) in the 18L/6D treatment among treatments, but alanine aminotransferase levels were significantly higher (P<0.05) in the 22L/2D treatment than in the 24L treatment. Levels of cytokines, i.e., Interleukin-6 and Tumor Necrosis Factor-α did not show a significant difference among the treatments, but corticosterone content was significantly higher (P<0.05) in the 24L treatment than in the 18L/6D treatment. In conclusion, 22 hours of lighting is appropriate between 1~7 days after hatching, considering growth performance and the overall health of broiler chicks.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.301-309
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• 1985

This experiment was conducted to know a substantial body of information about the differences of the important forage characteristics; green fodder yield, dry matter yield, TDN%, TDN yield and so forth of the seven cultivars selected as the forage crops (Rye, Triticale, Wheat and Barley) depending on the specific times of cutting stage, on the Wheat and Barley Research Institute from October, 1983 to June, 1984, and the results summarized as follows. Green fodder yield & dry matter weight, when clipped at 20, 30 April and 10 May, of varieties Homil #2 showed the most yielding capacity, but when clipped at 20 May, Suweon#8 (triticale) showed the most green fodder yield whereas Homil #1 the most significant dry matter weight. Plant height, in the cases of Paldanghomil, Homil #1 & Homil #2, showed distinctly longer than that of Bunong, Suweon #8 & Suweon #9 and continued to grow even after the heading date. Dry matter ratio increased with time (Dry matter yield/green fodder yield x100). TDN % decreased but TDN yield increased with time but Homil #1, Homil #2 and Paldanghomil showed relatively the higher values. In the elements of nutrient of cell wall, Suweon #8 & Bungong among 7 cultivars have good quality. The reasonable clipping date of wheat &barley as green fodder crops are 10 May to 20 May, but if clipped before 10 May and 20 May, Homil #2 and Suweon #8 became the promising forage crops, respectively.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.1-13
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• 2023

The study was carried out to investigate the effects of dietary combined supplementation of antioxidants as catechin and vitamin C on growth performance, meat quality, blood profiles and stress responses of broilers exposed to high temperature. For this experiment, a total of 360 21-day-old male Ross 308 broilers were used. Treatments were assigned with 6 replicates per treatment and 10 birds per replicate in a 2 × 3 factorial design with vitamin C (0, 250 mg/kg) and catechin (0, 600, 1,200 mg/kg). The heat stress environment was maintained at temperature 32±1℃ and relative humidity 60±5% for 24 hours until the end of the experiment. The supplemented antioxidants had no significant difference in weight gain, feed intake and feed conversion ratio (P>0.05). The content of total cholesterol in blood had no interaction, but decrease (P<0.01) in the supplemented catechin group. Also, the supplementation with catechin showed increase in the SOD activity of blood, and lower corticosterone and IgM levels of broilers. The contents of HSP70 and MDA in liver decrease (P<0.05) with the supplementation of antioxidants, and HSP70 showed an interaction between groups. DPPH radical scavenging ability in breast meat increased (P<0.01) in catechin, but meat quality did not show difference according to treatments. Respiratory rate decreased (P<0.05) in catechin, but no interaction with vitamin C. In conclusion, the combination of vitamin C and catechin can alleviate stress under high temperature, such as HSP70 and MDA, but further study on the optimal supplemental level is needed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.319-325
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• 2022

Triticale forage has the highest yield of all winter forage crops, including rye, and a cold tolerance within an average low temperature of -10℃ in January. Therefore, this study analyzed the effects of sowing and harvesting times on the feed value and functional components of triticale to optimize the use and supply of triticale as livestock fee Room temperature' can vary widely with climate, season, and time of day. In order to clearly state the conditions of the study in a manner that facilitates replication by other researchers, please consider using an approximate temperature range instead. Seeds of the triticale 'Joseong' were sown during the fall of 2021 (October 20th) and spring of 2022 (March 7th). The triticale was harvested at the following growth stages: seedling stage, booting stage, heading stage, 10 days after heading, and 20 days after heading. The moisture content of each harvested triticale was adjusted to approximately 60%, and the triticale was fermented for silage for 40 days at ambient temperature under anaerobic conditions. We measured the pH and organic acid content of each silage to determine the feed value and functional component. The lactic acid content of the triticale silage harvested at the seedling stage sown in both fall and spring (1.61%, 1.63%) was the highest among all the silages. The octacosanol content in the silages of both fall-sown and spring-sown triticale harvested at the seedling stage (0.38, 0.27 mg/ml) was the highest. Overall, the results revealed that harvesting time had a greater impact on the feed value and functional components of triticale silage than sowing time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.27-33
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• 2023

Several domestically consumed sweetpotato derivatives, such as sweetpotato starch for processing raw materials, frozen and refrigerated paste, and powder are dependent on imports. This study was conducted to examine the suitability of sweetpotato cultivars of twelve varieties (powdery-type and viscous type) cultivated in paddy fields, for use in starch, chips, dried products, and beverages. The two-year average yield results of the four cultivars suitable for starch (in order of highest to lowest yield) was as follows: Gogeonmi (4,018 kg/10a); Daeyumi (3,615 kg/10a); Jinhongmi (3,426 kg/10a); Singeonmi (2,837 kg/10a). The starch content was 20.2%, 18.2%, 21.2%, and 20.6% in Daeyumi, Gogeonmi, Singeonmi, and Jinghongmi, respectively. The total amount of starch was higher in Daeyumi (730 kg/10a) and Gogeonmi (731 kg/10a) than that in Singeonmi and Jinghongmi. The yield of Pungwonmi and Shinjami were 4,443 and 3,602 kg/10a, respectively. Powdery-type sweetpotatoes (Daeyumi and Gogeonmi) showed the low decay rates of all cultivars (0.8 and 0%, respectively). The yield of the storage root formation and storage root swelling stages by water-logging treatment decreased by 16.5% and 15.4% for Pungwonmi, and by 17.2% and 10.0% for Shinjami. Drainage management of paddy fields is necessary to reduce the damage caused by water-logging. Our results suggest that cultivation of sweetpotato varieties suitable for processing raw materials in paddy fields will enable stable yields of sweetpotato with a high starch content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.199-210
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• 2022

This study aimed to develop a cropping system to use limited crop-land with optimum efficiency, while considering management from farmers. To establish the cropping system involving a two-year rotation of three crops, three types of cropping system were evaluated in Suwon (Seogcheon series) and Anseong (Geumcheon series) in the middle plain area using six crops from 2018 to 2019: maize-perilla-onion, potato-sesame-garlic, and maize-sesame-onion. The crop productivity and income of the cropping systems involving food-, oilseed-, and horticultural crops were analyzed, and the optimal cropping system was reviewed. The total yield of each crop was as follows: maize 1,281 kg, potato 4,837 kg, perilla 125 kg, sesame 120 kg, onion 6,503 kg, and garlic 1,027 kg per 10a. However, in terms of gross profit, the potato was more than 3.8 times more profitable than corn, sesame was 1.8 times more profitable than perilla, and garlic was more than 2.8 times more profitable than onions. As a result, in terms of net income, the potato-sesame-garlic cropping system produced the highest income per unit area. Sesame seedlings were planted after the potato harvest, thereby solving the problem of competition between the first and last crops. Overall, this study confirmed that the potato-sesame-garlic cropping system, a two-year rotation of three crops, contributed to the improvement of upland crop productivity and farmers' income and was an overall effective cropping system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.20-26
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• 2023

Fiber content in the storage roots of sweetpotato varies between different varieties. For examples, the high fiber content of certain types has a poor texture when steamed or roasted. This study was conducted to evaluate the optimal sieve mesh size for separating fibers, the chemical composition of fibers and differences in fiber content among different varieties. We found that the separated fiber content (dry weight) of mashed and steamed sweetpotato was higher after washing three times (143.3 mg/100 g) compared with that washed five times (128.4 mg/100 g). The Hogammi variety remained 85.9% of total fiber content at 10 mesh (2,000 ㎛) and 9.6% of total fiber content at 30 mesh (600 ㎛), and Jinyulmi remained 74.9 and 16.7% of total fiber content , respectively. Therefore, a 30 mesh sieve was considered the most suitable for fiber separation. Among the 10 studied cultivars, Jinhongmi showed the lowest amount of fiber (24.8 mg/100 g) and Hogammi had the highest amount (111.4 mg/100 g), which was 4.5 times larger than that of Jinhongmi. Cellulose, hemicellulose and lignin content of separated fibers showed no difference between the viscous-type Hogammi and powdery-type Jinyulmi varieties, with averages of 32.5, 22.3 and 29.6%, respectively. Correlation results using the Image J program showed a significant correlation between the distribution of the stained area and the fiber content (R = 0.74, p < 0.05). Staining distribution differed among varieties, suggesting that a simple fiber content test could be performed using the staining method on raw sweetpotato. These results provide useful information to help inform farmers on the fiber content of different sweetpotato varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.159-164
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• 1973

This study was carried out in the central part of Korea for three years from 1970 to 1972. Its aim was to investigate the variations of growth and yield of rice varieties of different cultivating methods (transplanting culture, direct sowing culture on irrigated paddy field, and direct sowing culture on non-irrigated paddy field. The results could be summarized as follows; 1. The number of days from sowing to heading by direct sowing culture on irrigated paddy field was remarkably shorter than transplanting culture. Direct sowing culture on non-irrigated paddy field was longer than transplanting culture. 2. The number of panicles showed direct sowing culture on irrigated paddy field was first, direct sowing culture on non-irrigated paddy field was second, and third transplanting culture. But the number of spikelets per panicle was first on the transplanting culture, second on the direct sowing culture on non-irrigated paddy field and third on the direct sowing culture on irrigated paddy field. 3. The weight of the brown rice showed that direct sowing culture on irrigated paddy field produced the highest yield among the cultivating method in all varieties. The transplanting culture increased more than the direct sowing culture on non-irrigated paddy field. The highly productive varieties were Sadominory, Akibale, Suwon 213-1 when the direct sowing culture on irrigated paddy field was used. 4. The correlation between the brown rice yield and the yield components were as follows; in each cultivating method, it showed highly significant positive correlation between the brown rice yield and the 1, 000 grain weight of hulled rice, and between the brown rice yield and the number of the spiklets per panicle in the transplanting culture, in the direct sowing culture On irrigated paddy field between the brown rice yield and the number of spikelets per panicle and between the brown rice yield and the number of panicles, in direct sowing culture on non-irrigated paddy field between the brown rice yield and number of panicles. 5. It showed highly significant negative correlation between the brown rice yield and the number of days from sowing to heading in the direct sowing culture on irrigated and non-irrigated paddy field, but it was showed very low negative correlation in the transplant culture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.35-42
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• 1980

To establish a generation acceleration technique, two crops a year at field condition of Suweon, 10 varieties different in their spring growth habit were tested with 6 different seeding time after harvesting. These materials were harvested on June 10, 19, 79 and tested for their seed production ability at varions seeding time from July I I to August 15 with a week interval. An immatured seed germination technique and green vernalization methods were applied in cycling generations and the results obtained were summarized as follows. 1. In summer growing, seedlings establishment after transplanting was better in earlier transplanting. 2. Heading time was remarkably enhanced by earlier transplanting. Considering the results of two years early or mid of July was the suitable time to plant the second summer crop. 3. Those varieties of spring growth habit expressed little variations in plant height among the varieties. In 1978 which is referred as warm year produced plant height as tall as 8-16cm and poor crop but produced good crop with 25-65cm plant height in 1979. 4. No definit tendency in the length of spike was. observed among the cultivars but longer spike was found in winter wheat compared to the spring. 5. Number of spikes per plant was ranged from 1 to 3 regardless the transplanting time in 1979. However, more spikes per plant were produced in early or mid of July transplanting and those varieties of higher growth habit than V did not produces any spikes. 6. Higher number of grains per spike was found at earlier transplanted varieties. Therefore, it is concluded that those materials of I-IV growth habit with mid or early July transplanting would be suitable in practical sense considering their ability of seed production. 7. Two-year results indicated that wheat crop can not tolerate the temperature level higher than average 32$^{\circ}C$ C at Suweon. In this regard, the cultivation schedule was established assuming average temperature condition like the year of 1979 which was possible to grow wheats.