• 한국수산과학회지
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• 제8권4호
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• pp.234-241
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• 1975

여수근해산 한전복 Haliotis discus hannai를 재료로 1973년 1월-12월까지 매월 1회씩 24회에 걸쳐 생식선열도지수, 성열도계수, 비만도등의 월변화와 각장 및 전중량의 생식선중량과의 관계, 수온조건 및 자연산모패의 산란유발 결과를 요약하면 다음과 같다. 1. 여수근해산 한전복의 산란가능기간은 5월 하순-7월하순과 9월상순-11월하순이며, 주요산란기는 5월하순-6월중순과 9월하순-11월하순으로 각각 추정되었다. 2. 생식선성열도계수가 극대치를 보인 것은 5월의 44.10과 9월의 49.05였고, 최소치는 1월의 10.09였다. 3. 비만도는 년중 7월이 0.221로 가장 높았으며, 10월에 0.1058로 가장 낮았다. 4. 각장(SL)에 대한 생식선중량(GW)의 비가 년중 가장 높았던 달은 9월이었고, 가장 낮았던 달은 1월로서 이때의 관계식은 9월 : $GW=0.0000003710SL^{3.7860}$ 1월 : $GW=0.000021198SL^{2.8564}$ 각년평균치 : $GW=0.0000005013SL^{4.2273}$ 으로 각각 표시되었다. 5. 전중량(TW)에 대한 생식선중량(GW)의 비가 년중 가장 높았던 달은 9월이었고, 가장 낮았던 달은 1월로서 이때의 관계식은 9 月 : GW=0.1918TW-4.9231 1 月 : GW=0.0992TW-0.1759 주년평균수 : GW=0.1568TW-3.5236으로 표시되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제9권3호
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• pp.247-254
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• 1996

Three stages of growth of Italian ryegrass (pre-blooming, P-B; early-blooming, E-B; and late-blooming, L-B) were used to evaluate the effect of maturity on in vitro digestion of dry matter, fiber components and gas production. The rumen digestibility and gas production values were obtained by incubation of each sample in the rumen fluid of sheep for 12, 24, 36, 48 and 72 hr, respectively. The results showed that digestibility of dry matter (DM) significantly reduced (p < 0.05) as advancing maturity of the grass. Similarly, the digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF) also significantly decreased (p < 0.05) with advancing maturity at all incubation times. However, the effect of maturity on digestibility of cellulose and hemicellulose was only detected when the samples were incubated more than 36 hr, where L-B was lower than P-B and E-B. Potential digestibility of nutrients, the maximum digestibility attainable in the rumen theoretically, was also higher at P-B than those of E-B and L-B. The amount of gas produced by microbial fermentation was closely related to the extent of DM digestion, and it was negatively correlated with advancing maturity of the grass.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.108-108
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• 2017

The objective of this study was to know prospect and present state of new variety breeding of Forage and Grassland in South Korea. The industry of forage in Korea is going up to expend through utilization of good quality forage, Italian ryegrass, forage corn and oat rather than rice straw. Especially, since 2007, Italian ryegrass(IRG) had been very important major winter forage crop in South Korea and developed 13 varieties including very early maturity variety (three varieties), early maturity variety (three varieties), medium maturity variety (one variety) and late maturity variety (six varieties). But the disadvantage of Italian ryegrass was weak winter hardness and drought but has good advantage of forage nutritive value, high-yielding and high sugar content, and like livestock as like hanwoo, dairy cattle, goat so on. The Ko-variety (Korea developed variety) of Italian ryegrass has high cold-tolerant and adaptability more than any other country developed variety, and expend to cultivation area from southern area (below Daejeon) to middle-northern area (upper Han river). Although the cultivation area of Italian ryegrass of South Korea was 21,700 ha in 2007, right now, that of Italian ryegrass is about 123,600ha due to expend cultivation area and know famer to good forage crop and have a various maturity varieties (very early, early, medium, late) according to local situation (before-crop harvesting stage or double cropping system). The seed market of Italian ryegrass in South Korea becoming extended to around 100 million Korean won and seed export get nearer to foreign country. We are going to develop of new variety for stress tolerant and high yield and quality forage variety, good adaptability to the Korean environmental conditions including reclaimed area, make self-sufficiency system for forage seed (Italian ryegrass), export our seed to foreign countries.

• Animal cells and systems
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• 제5권1호
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• pp.37-44
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• 2001

Gonadal development, reproductive cycle, gonad index, meat weight rate, and first sexual maturity of the top shell, Omphalius rusticus were Investigated monthly by histological observations. Specimens were collected from the west coast of Korea during the period from January to December in 1999. O. rusticus is dioecious and oviparous. The gonad is widely situated on the surface of the digestive g1and located in the posterior spiral meat part in the shell. The ovary and the testis were composed of a number of oogenic follicles and several spermatogenic follicles, respectively. Ripe oocytes were approximately 120-130 $\mu$m in diameter. The meat weight rate peaked in June (27.7%), and then rapidly decreased in September (19.5%). Monthly changes in the gonad index in both sexes reached the maximum in June, and then sharply decreased in September. Percentages of first sexual maturity of female and male snails ranging from 9.0 to 9.9 mm in shell heights were 58.3% and 54.5%, respectively, and 100% in those over 11.0 mm in both sexes participated in reproduction. Reproductive cycle of this species can be categorized into five successive stages: in females, early active (October to April), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to January): in males, early active (November to March), late active (December to June), ripe (April to September), spawning (July to September) and recovery (September to December). Gonadal development, gametogenesis, reproductive cycle, and spawning were closely related to the seawater temperature.

• 한국초지조사료학회지
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• 제20권3호
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• pp.147-154
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• 2000

This study was conducted to increase the utility and productivity of forage crops at high altitued areas. For that purpose, 21 cultivars of corn and 2 cultivars of rye were cultivated for 3 years using a randomized block designed with 3 replications. The results obtained were as follows. 1. In the Taekwallyong area (800m above sea level) which has a short frostless period, all the seeding and harvest of corn must be finished within about 135 days between mid May, the time of the last frost, and late September, the time of the first frost 2. It was relatively safe for the early maturity cultivar(ll0days) and the medium maturity cultivar(l20days), compared to the late maturity cultivar(l30days) which might have had the possibility of an overlapping period between the time of harvest and the first frost in high altitude areas 3. The productivity of forage corn, which is the most efficient crop for capturing solar energy, varied significantly with the climate circumstances but the productivity of Taekwallyong showed similar results of 19 M/T/ha, compared with 20 M/T/ha in Suwon from the '96-'98 study 4. Rye could be cultivated in high altitude areas and when corn was raised as a second crop after rye in the same year, it was possible to increase the productivity of dry matter yield by 20% through double cropping(P < 0.05). (Key words : Cropping system, Corn, Rye, Forage production)

• 가정과삶의질연구
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• 제23권6호
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• pp.167-178
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• 2005

The purpose of this study was to investigate various assects of late parenthood among Korean parents, including motivation, emotional response, advantages and disadvantages of late parenthood, intimacy, and effects on child. Subjects were IS mothers who gave birth after 35 years old for both mother and father. The study was conducted by means of a questionnaire and an in-depth interview. The most significant reason for late parenthood was found to be a son preference. brothers of the only could expressed very special emotional responses toward the child, compared to those who gave a birth to the second or the third child after 35. Respondents identified advantages and disadvantages of late parenthood in terms of child rare attitudes, maturity, financial conditions, and physical strength. However, most of the respondents would not recommend late parenthood to others. Directions for future research were given in terms of subjects of study, such as parents from rural area, working class, and wide range of ages.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권1호
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• pp.15-19
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• 2003

The study evaluated the influence of feeding different maturity leaves i.e., tender, medium, coarse and mixed leaves of three different maturity during late larval stages of new bivoltine race $(CSR_{3} {\times} CSR_{6})$. The data were compared with shoot feeding and control batches in which conventional feeding method was followed. The most of the larval and cocoon characters were recorded significantly higher in tender leaves fed batches followed by T4 batch (2 times tender and 1 time coarse leaves). Lowest melting percentage (1.494%) was recorded in T4 and highest (4.69%) was recorded in coarse leaf (T3) fed batches. Significantly higher post cocoon parameters viz., average filament length, non-breakable filament length, renditta and raw silk percentage were recorded in tender loaves fed batches.

• 한국연초학회지
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• 제5권2호
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• pp.25-32
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• 1983

To obtain basic information on the breeding of burley tobacco, classification of 41 varieties was carried out by using the cluster analysis of correlation coefficients and taxonomic distance based on twenty-one agromonic characters. Eight characters, such as days to flowering, length of flower axis, internode length, leaf length, yield, leaf angle to stem, vein angle to midrib and plant height, were useful in monothetic classification. Forty-one varieties were classified into four groups (I, II, III and IV) with weighted variable group method (WVGM ) and weighted jai. group method(WPGM), whereas the results classification of 33 varieties among them by WVGM were coincident with the results by WPGM. As for the characteristics of each group, group I related to late maturity, tall height and high yield, group II related to intermediate maturity, tall height and low yield, group 19 related to early maturity, intermediate height and low yield, and group W related to early maturity, short height and intermediate yield.

• 한국작물학회지
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• 제61권2호
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• pp.104-112
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• 2016

A double-cropping system with soybean (Glycine max) following the cultivation of potato, garlic, and onion is widely adopted in the southern region of Korea. For this system, marginal dates for planting must be determined for profitable soybean yields, because the decision to plant soybean as a second crop is occasionally delayed by harvest of the first crop and weather conditions. In order to investigate the effect of planting date on soybean yield, three cultivars (early and late maturity) were planted on seven different dates from May 1 to July 30 in both paddy and upland fields across 2012 and 2013. Soybean yields were significantly different among the planting dates and the cultivars; however, the interaction between cultivar and planting date was not significant. Based on linear regression, the maximum yield of soybean was reached with a June 10 planting date, with a sharp decline in yield for crops planted after this date. The results of this study were consistent with those of a previous one that recommends early and mid-June as the optimum planting period. Regardless of soybean ecotype, a reduction in yield of greater than 20% occurred when soybean was planted after mid-July. Frost during soybean growth can reduce yields, and the late maturity cultivars planted on July 30 were damaged by frost before completing maturation and harvest; however, early maturity cultivars were safely harvested. For sufficient time to develop and reach profitable yields, the planting of soybean before mid-July is recommended.

• 한국작물학회지
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• 제66권1호
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• pp.18-28
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• 2021

남부지역 논에서 식량작물을 최대로 생산하기 위해 밀양시 국립식량과학원 시험포장에서 2015~2018년의 4년 동안 겨울밀-벼, 겨울밀-콩 및 겨울밀-곡실용옥수수의 이모작 체계의 생육기간 및 생산성을 비교하였다. 밀의 수확적기는 6월 중순으로 하작물은 6월 하순에 파종(이앙)이 가능하였다. 벼의 6월 하순 이앙 시 안전출수와 벼의 수량성 확보에는 지장이 없었지만 가을에 성숙기가 늦어 뒷그루 밀 파종에는 지장이 많았으며, 특히 중만생종 벼의 경우 수확기가 11월 상순으로 늦추어져 밀의 적기파종이 어려웠다. 콩은 6월 하순이 파종적기이므로 작기상 큰 문제가 없었으며 성숙기도 10월 중순으로 11월 상순의밀 파종에 큰 무리가 없었다. 곡실용옥수수는 6월 하순 파종 시 성숙기가 가장 빨라 밀과의 이모작에서 작기상 가장 유리하였다. 겨울밀-하작물 이모작에서 밀은 콩과 곡실용옥수수 후작에서는 안정적인 수량성을 얻을 수 있었지만 벼의 후작에서는 강우가 많은 해에는 수량이 감소할 위험성이 있었다. 벼, 콩, 곡실용옥수수의 수량성은 각각 600, 350, 800 kg/10a로 높은 수량성 확보가 가능하였고 중생종과 중만생종간의 수량성에 큰 차이를 보이지 않아 중생종이 만생종보다 이모작에 유리하였다. 토양 물리성에서도 콩과 옥수수 등 밭작물의 도입 시 물리성이 좋아지는 것으로 나타났다. 따라서 남부지역 논에서 밀-콩/곡실용옥수수 이모작은 작기 연결성 및 토양개선, 소득성(콩)에서 밀-벼 이모작보다 우수한 것으로 나타났다.