This study was conducted to determine the appropriate seeding dates by verifying the difference in winter survival and productivity of alfalfa according to fall sowing dates in the central area of South Korea. The experiment was conducted for 2 years (2020 and 2021) at the field in the Department of Animal Resources Development, NIAS located in Cheonan. Sowing dates started from September 18 to November 8 with 10 days of intervals during 2020 and 2021; SO1 (September 18), SO2 (September 28), SO3 (October 8), SO4 (October 18), SO5 (October 28), and SO6 (November 8). After sowing, the winter survival rate was measured in the spring of the following year, and the dry matter yield was measured by harvesting at 10% flowering and harvesting five times a year. SO6 failed to winter survival, and SO5 also had a lower winter survival rate than SO1~4 (p<0.05). The average annual dry matter yield of alfalfa linearly decreased with delaying sowing dates (p<0.05). The feed value did not differ in the same year by delaying the sowing date in the same year. These results suggest that sowing date should be started before October 18 to increase winter survival and productivity of alfalfa in the central area of South Korea.

The aim of this study was to investigate dry matter productivity and nitrate nitrogen content in the growth stages of barnyard millet (Echinochloa esculenta) cultivated for feed, which was treated with different nitrogen fertilization levels. An early variety of barnyard millet (cv. Shirohie) was used for the test, and the different treatments with nitrogen fertilizer were as follows: 50% (N-40 kg/ha, T1), 100% (N-80 kg/ha, reference amount, T2), 150% (N-120 kg/ha, T3), 200% (N- 160 kg/ha, T4), 250% (N-200 kg/ha, T5), and 300% (N-240 kg/ha, T6). Sowing was done on May 13, 2021 and plants were harvested for four stage; vegetative stage, elongation stage, heading stage, and milk stage. The length of the millet increased significantly as the amount of nitrogen fertilization increased during the harvest period (p<0.05), but the difference was insignificant during the milk stage (p>0.05). Moreover, barnyard millet dry matter yield increased significantly as the levels of nitrogen fertilization increased (p<0.05), but there was no significant difference in dry matter yield among nitrogen fertilization levels during the heading stage (p>0.05). Chlorophyll also was significantly higher in T5 (250%) at all harvesting times, whereas nitrate nitrogen content was highest at the vegetative stage, gradually decreased as growth progressed, and lowest at the milk stage. Finally, as the nitrogen fertilization levels increased, the nitrate nitrogen content was significantly higher in all treatment groups (p<0.05). Therefore, our results suggest that the most appropriate nitrogen fertilizer levels is between 150%–200%, considering the dry matter yield, feed ingredients and nitrate nitrogen content in barnyard millet for feed.

This study aimed to examine the changes in dry matter yield and growth characteristics of alfalfa (Medicago sativa L.) in response to variations in sowing dates during the autumn season of 2021-22 in a dry paddy field of Chilbo-myeon, Jeongeup-si, Jeollabuk-do. Treatments comprised four sowing dates at 10-day intervals, i.e., October 8, October 18, October 28, and November 8, 2021. The winter survival rate of alfalfa showed a significant difference between different treatments but was at a satisfactory level for all (p<0.05). The winter survival rate for the fourth sowing date, a month later than the first sowing date, was approximately 11.7% lower than that for the first sowing date. The plant height ranged between 82.3–93.1 cm and 60.5–63.7 cm at the first and second harvest, respectively, smaller at the second harvest than at the first harvest. The total dry matter yield of alfalfa was the highest at 13,316 kg/ha for the first sowing date, and the later the sowing date, the lower the dry matter yield. The protein content of alfalfa ranged between 13.6–17.3% in the first harvest, lower than the standard alfalfa protein content of 20% or more. In relative feed value, the first sowing (Oct. 8) was the most significantly higher in the first harvest (p<0.05). These results suggest that the early and mid-October sowing dates are optimum for sowing alfalfa during autumn and result in improved plant growth, dry matter yield, protein content, and winter survival compared to those at later sowing dates. Therefore, dry paddy fields can be safely employed for alfalfa cultivation with sowing dates in early and mid-October during autumn.

Barnyard millet (Echinochloa esculenta) can be processed through soiling, hay, and silage, depending on the weather conditions during harvesting. However, research on barnyard millet is insufficient, and standards for cultivar, seeding density, and fertilizers have not been established. This study was conducted to examine the effects of seeding density and seeding methods on dry matter yields. For this, we used the early-maturing (Shirohie millet) variety of the barnyard millet. The experimental design included different seeding density (10 kg/ha, 15 kg/ha, 20 kg/ha (standard seeding density), 25 kg/ha and 30 kg/ha), and different methods of seeding (drill seeding and broadcast seeding). The seeding date was May 13, 2021, and the harvest date was July 13, 2021. Harvesting was carried out when the heading reached 40 %. Lodging occurred at 5, 9 and 7 at 20, 25 and 30 kg/ha densities in the broadcast seeding, but not in the drill seeding. With decreasing density of seeding, tillage number showed an increasing trend in both drill seeding and broadcast seeding (p>0.05). The plant heights were comparable in both drill seeding and broadcast seeding (p>0.05). The heading stage of barnyard millet was checked July 7 for drill seeding, and, on July 8 for broadcast seeding. It took 62 days, i.e., till July 13 for the heading to reach 40 % of the output. The dry matter yield of barnyard millet was significantly higher at the seeding density of 30 kg/ha, for both the methods of seeding (p<0.05). There was no difference in the chemical composition of grain, based on the seeding method and seeding density. However, as the seeding density increased, the CP, NDF, ADF, and TDN contents increased in both drill seeding and broadcast seeding. We found that, the dry matter content was the highest at the seeding density of 30 kg/ha for both the methods of seeding, but this was only 1.3 times higher than that of 10 kg/ha. Considering the seed price and labor force involved in seeding, it is advisable to have a seeding density of 15-20 kg/ha.

국내 판매되고 있는 사슴벌레종[넓적사슴벌레(Dorcus titanus), 참넓적사슴벌레(Serrognathus consentaneus), 남방넓적사슴벌레(D. titanus jejuensis, 가칭), 애사슴벌레(D. rectus) 및 왕사슴벌레(D. hopei)]과 부산 지역에서 채집한 넓적사슴벌레 12개체와 경남 의령군에서 채집한 1개체의 미토콘드리아 DNA 중 cytochrome oxidase I(COI) 를 이용하여 계통을 비교분석하였다. 아울러 NCBI에 기등록된 북한, 일본, 대만, 필리핀, 인도네시아 및 태국의 넓적사슴벌레의 COI 서열을 이용하여 추가 분석하였다. 먼저 판매되고 있는 사슴벌레종은 넓적사슴벌레, 남방넓적사슴벌레 및 참넓적사슴벌레의 group I과 애사슴벌레 및 왕사슴벌레의 group II로 구분되었다. 부산지역 및 의령에서 채집한 넓적사슴벌레의 경우 COI 및 COII로 분석 결과 북한에서 기보고 된 3개체를 포함해 유전적 변이에 있어 큰 차이가 나타내지 않았다. 또한 한반도와 일본 일부지역에서 높은 상동성을 확인하였는데 그 외 아시아 지역에 서식하는 넓적사슴벌레와는 다른 그룹을 형성함을 확인하였다. 이러한 결과들은 국내 서식 사슴벌레 종의 유전적 분석과 함께 외래 유입종을 판별하는 근거자료로 활용될 수 있을 것이다.

최근에 와서 해양연구활동은 국가적 영토관리개념을 넘어 전지구적인 연구영역으로 급속히 확장되고 있다. 이와 같은 연구 추세는 기후, 자원, 환경과 영토관리 등 해양을 대상으로 하는 연구스펙트럼이 급격하게 확대되고 있다는 것을 의미하며, 이에 따른 해 양연구인프라 또한 대형화되고 정밀화되는 것이 불가피하다. 그러나 한편으로는 이와같은 연구인프라는 운용과 관리 측면에서 소요되 는 비용부담이 크고 국가재정 의존도가 높기 때문에 효율성을 고려한 국가전략적 차원의 대응방안 마련이 필요하다. 본 연구에서는 국 내기관간 또는 국가간 해양연구의 기본인프라인 연구·조사선 공동활용체계를 구축하여 시행하고 있는 주요 선행국의 운용체계 형태와 특성을 분석하고 연구조사선을 보유하고 있는 국내 주요 기관을 중심으로 공동활용 운영체계 유형과 각 유형별 효율성을 비교·분석하 였다. 주요 선행국의 운영형태와 국내 여건을 고려하였을 때, 구현 가능한 국내 공동활용 운영체계는 공동활용위원회(유형 1), 민간기 업 위탁(유형 2), 정부출연기관내 기관출자(유형 3)과 위탁집행형(유형 4)로 요약될 수 있다. 현재의 운영체계와 4가지 유형의 운영체계 에 대한 비용-편익 분석 결과, 유형 1, 2, 3과 4의 효과성 비율은 각각 9.17, 5.82, 11.2와 -1.72%로 나타남에 따라 유형 1(공동활용위원회 운영체계)가 소요비용측면에서 가장 효율적인 대안인 것으로 나타났으며, 편익적 측면에서는 유형 3(정부출연기관내 기관출자)의 기관 출자 방식 운영체계가 가장 효과적인 것으로 해석되었다.

Allomyrina dichotoma is a typical pet beetles in Korea. From 2010, similar symptoms of milky spore disease were found collectively in grubs of the species reared in insect farms. They shared a specific symptom that the skin of last instar larvae was changed softer with opaque white and infested grubs eventually died. To clarify the cause of the symptom, we collected the larvae of A. dichotoma from five farms and examined intestinal bacterial florae of them using pyrosequencing technique. From those results, a member of Paenibacillus was found only in the larvae showing the symptom of disease. Through PCR analysis using a Paenibacillus specific primer set, we obtained the partial 16S rRNA gene sequence and confirmed the microbe as Paenibacillus sp. For detailed characterizing, a whole guts was extracted from each larva showing the sign of the disease and incubated at 70℃ for 15 min to isolate spore forming bacteria. After then, each content of guts was cultured on MYPGPNAL agar medium (12.5 μg/ml of nalidixic acid) at 30℃. The 16S rRNA gene sequence analysis for six isolate showed that they were closely related to P. rigui (97.5~98.0% similarity) and to P. chinjuensis (95.9~96.6% similarity). Additional tests including API test and cellular fatty acid composition analysis were performed, but the strain couldn’t be identified at species level, suggesting it may represent novel species of the genus Paenibacillus.

This study was to investigate pregnancy rate of IVM/IVF/IVC Korean cattle (registered in government) embryos according to transport time course. For the production of embryos, oocytes recovered from slaughtered excellent grade cow and highly motile frozen‐thawed bull semen (purchased from LIMC, KPN#497) was used. In vitro produced embryos were cultured in CR1aa medium for 8 days and some of them were frozen. The rate of average cleavage (>2‐cell) was 83.0% (308/371) and blastocyst rate at day 8 was 34.7% (107/308). Among in vitro produced blastocyst embryos at day 8, most healthy embryos were freshly transferred on production day and some frozen embryos were direct transferred on appropriate day. These embryos were produced in a laboratory, embryo transfer (ET) was planned in 10 areas of the remote island (Jeju) from the laboratory by airplane. Thus, we examined the pregnancy rate in recipient cow according to embryo of transport time course before ET. From embryo transferred 44 recipient cows, overall pregnancy was 40.9% (18/44), these 18 cows were all calved [single, 94% (17/18); twin, 6% (1/18)] and total embryo implantation rate was 26% (19/66). Comparing transport time in the base of 6 hr, pregnancy rate in ET group required less 4 hr (60%, 9/15) was significantly higher than that required more 6 hr (26.3%, 5/19). In direct ET of freezing embryos, the pregnancy rate was 40% (4/10). However, it was difficult to find the meaning of temperature, pH and corpus luteum quality of recipients on comparison of pregnancy rate. When the cell death level of embryos according to storage time in thermos (straw container) before ET was measured by TUNEL staining, apoptotic index was increased with storage time‐dependent. These results demonstrated that long distance transfer of IVM/IVF/IVC embryos is possible and the time of embryo transport is very important for the pregnancy rate on field trial.

This report describes the sex differentiation of the Korean rose bitterling, Rhodeus uyekii, from hatching to 170 days post-hatch (DPH) in relation to total length (TL), body weight (BW), and integral water temperature (IWT). The growth curve of TL from just hatching to 83 DPH was 5.144e0.045t (R² = 0.961; t, time), and that of BW was 2.398e0.086t (R² = 0.725). Primordial germ cells (PGCs) were observed at 17 DPH (7.9 mm TL, 3.74 mg BW, 374°C IWT), and thereafter began to protrude into the peritoneal cavity. At 21 DPH (9.2±0.14 mm TL, 4.8±0.07 mg BW, 462°C IWT), some PGCs contained condensed chromatin and oocyte were observed in meiotic prophase. In contrast to the ovaries, which grew gradually after sexual differentiation, testes began multiplying at 25 DPH (10.1 mm TL, 5.42 mg BW, 550°C IWT), when testicular differentiation was first identified, and multiplied continuously thereafter. At 33 DPH (11.2 mm TL, 10.5 mg BW, 726°C IWT), the developing testes contained spermatogonia that exhibited mitotic activity. No spermatocyte or sperm cell was observed until 83 DPH (18.9 TL, 48.2 mg BW, 1,826°C IWT). At 170 DPH (32.5 mm TL, 270.1 mg BW, 3,740°C IWT), which was the end point of this study, the mature ovaries showed germinal vesicle breakdown, while the mature testes contained observable spermatocytes and sperm cells. These results allow us to identify the sex differentiation type of the Korean rose bitterling as differentiated gonochoristic.