• The Korean Journal of Malacology
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• v.23 no.2
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• pp.189-198
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• 2007

The reproductive cycle, egg capsules in the egg-mass, first sexual maturity, and sex ratio of the bladder moon, Glossaulax didyma ($R\ddot{o}ding$) were investigated. The gastropods collected from the intertidal zone of Biin Bay, Seocheon, Korea were studied by using histological analysis and morphometric data. The gonadosomatic index (GSI) of females and males began to increase in March and reached maximum in May. Then their values sharply decreased from late in May to August due to spawning. The condition index (CI) began to increase in February and reached maximum in May, then gradually declined in the spawning period. The CI calculated for determination of the spawning period was coincided with changes in the GSI and gonadal phases. Spawning occurred between late in May to August in females and early in May to August in males. Spawning peak was observed between July and August when the seawater temperature rose to 19 $^{\circ}C$. Reproductive cycle with the gonadal development phases of this species can be divided into five successive stages in females and four in males: in females, early active stage (December to February), late active stage (February to March), ripe stage (April recovery stage (August to November); in males, active stage (December to March), ripe stage (March to July), copulation stage (early May to August), and recovery stage (August to January). Fully matured oocytes were approximately 250-270 ${\mu}m$ in size. The egg-mass was a hat in shape, and a number of egg capsules were found in an egg-mass. An egg capsule was 0.53-0.57 mm in size. An embryo (veliger larva) hatched from an egg capsule. Percentage of first sexual maturity in females and males were over 50% for individuals that are 40.1-45.0 mm in shell radius, and 100% for those that are over 45.1 mm. The sex ratio of female to male was significantly different from 1:1 $(x^2\;=\;57.22,\;p\;<\;0.05)$.

• Korean Journal of Organic Agriculture
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• v.14 no.4
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• pp.385-397
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• 2006

This study was conducted to establish the environment-friendly cropping system of soybean in paddy field with different soil textures. When the soybean was cultivated in paddy fields, growth responses of testing cultivars varied depending on soil texture and cultivation method. Growth responses of soybean in sandy loam tended to be better than those in clay, however the effect of high ridged cultivation was distinguished in clay loam. Especially, formation of rhizome nodule was significantly different depending on soils ; more numerous rhizome nodules were formed in sandy loam compared to that in clay. Plant heights of Taekwangkong and Eunhakong were highest in clay and sandy loam, respectively, while the number of pods and branches of Eunhakong were most in both soils. In clay paddy field, growth responses of Eunhakong were best among the testing cultivars, however high ridged cultivation was more appropriate to the cultivar compared to level row cultivation regardless of soils. Taekwangkong showed the highest leaf area indexes during whole growth stages. Leaf development of Daewonkong was suppressed in clay at early growth stage, while it significantly increased as growth stages progressed. Most retard leaf development was observed in early maturity cultivar, Hwaseongputkong, since it seemed to be seriously damaged by excess-moisture injury in both soils. Comparing the dry weight of top plants and roots, plant growth was more affected by soil texture than cultivation methods at early vegetative growth stage, via verses at R2 or R5 stages. In yield characters and yields at R8 maturity stage, pods number of Eunhakong was significantly higher than those of Daewonkong and Taekwangkong estimating to 107 and 124 in clay and sandy loam, respectively. The ratio of ripened seeds was highest in sandy loam in combination with high ridged cultivation, while the lowest in clay with level row. The yields of Deawonkong and Eunhakong were higher compared to other testing cultivars ranged from $l82{\sim}286kg/ha$ depending on soils and cultivation methods. In results, growth responses and yields of testing cultivars tended to be higher in sandy loam in combination with high ridge compared to clay with level row.

• Horticultural Science & Technology
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• v.17 no.2
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• pp.123-126
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• 1999

Effects of garlic juice (GJ), ethanol- (GJAE) and ethyl ether extract of garlic juice (GJEE), onion juice (OJ) and ethanol extract of onion juice (OJAE), garlic juice+Merit Blue (GJ+MB), ethanol extract of garlic juice+Merit Blue (GJAE+MB), onion juice+Merit Blue (OJ+MB), ethanol extract of onion juice+Merit Blue (OJAE+MB), and Merit Blue (MB) on budbreak, flowering, and maturity of plastic house-grown 'Daebong' grapes (Vitis labruscana B.) were studied. MB alone and in combination with other formulae hastened the budbreak, and double application was more effective than single one. Most of the buds sprouted in early forcing, but percent budbreak in late forcing was very poor except for MB application. In early forcing, single application of MB in combination with other formulae was most effective for hastening flowering while the response to double application was not consistent, and even delayed the flowering except for OJAE, MB, and OJ+MB. In late forcing, single application of all dormancy-breaking agents, especially MB in combination with other formulae, hastened the flowering while flowering response to double application was inconsistent, and even delayed the flowering except for OJAE+MB and OJ. Although there were no significant differences in harvest date among treatments and the number of application in early forcing, single and double application of MB alone and in combination with other formulae, especially double application of OJAE+MB hastened the harvest date for 12 days in late forcing culture.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.79-88
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• 2022

This study was conducted to evaluate the productivity of whole crop silage wheat utilizing the paddy fields during a couple of years from 2019 to 2021 in Suwon, Korea. This investigation was used the two maturity types of wheat cultivar 'Cheongwoo' (early) and 'Taeu' (late). The heading date of 2^nd year (Oct. 2020 to May. 2021) cultivation was delayed about 11 to 13 days by more than 1^st year (Oct. 2019 to May. 2020). The growth characteristics were shown that the plant height was increased in 2^nd cultivation, while the number of culms and the panicle part ratio were decreased. Moreover, the nutritive value of 'Cheongwoo' and 'Taeu' were also decreased in 2^nd cultivation. These changes have thought to a difference of the precipitation by cultivation years. Because, the precipitation during the period from the end of winter dormancy to the harvesting stage in 2^nd (337 mm) cultivation was more about twice than 1st (169.3 mm) cultivation. However, the dry matter yield of 'Cheongwoo' was not shown a statistical difference by cultivation years, while 'Taeu' was shown to decrease tendency. The total dry matter yield regardless of the cultivation years were higher in 'Cheongwoo' than 'Taeu', and especially 'Cheongwoo' was more 3 tons per hectare (15.3 t/ha) than 'Taeu' (12.6 t/ha) at 2^nd cultivation (p<0.01). The trend of dry weight in 'Cheongwoo', early mature type, showed a relatively high ratio of dry matter (p<0.05) was considered that due to a high panicle ratio by a fast heading and an adequate weight of panicles by a sufficient maturing. In conclusion, selecting the early maturity cultivars could achieve a higher and more stable total dry matter yield considering the cropping system in the central region. Furthermore, it also has the advantage of being able to double-cropping system with forage rice, which has considered the maximum whole-crop forage production year-round. These results suggest that the 'Cheongwoo' be optimum cultivar to produce the year-round forage on paddy fields in the central region.

• Journal of the Korea Concrete Institute
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• v.16 no.3 s.81
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• pp.327-334
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• 2004

In this paper, method for the determination of removal time of the side forms in high strength concrete are discussed using the estimation model of compressive strength development, the development of bond strength and rebound number of P type Schmidt hammer in order to review the validity of existing regulation as to side form removal and offer effective quality control method. According to the results, as W/B increases by $10\%$, the setting time is shortened by about 2 hours. In the scope of the paper, required time to gain 8MPa of compressive strength is determined about 17 ${\~}$20 hours of age and $21{\~}25^{\circ}D{\cdot}D$ of maturity. Bond strength between form and concrete shows the highest value around final setting time, but decreases drastically after that. Amount of concrete sticking on the form is large before setting completed, but after that, its amount shows decline tendency. The rebound value test with P type schmidt hammer can be started faster by 2${\~}$3 hours than compressive strength test. It is also confirmed that the removal of forms is possible when the rebound value of P type schmidt hammer is more than 32. It is found from the results that existing regulation regarding removal time of the side form of high strength concrete provided in KCI needs no revision because required time to gain the strength provided in KCI has no adverse effect on strength development at early age and surface condition during stripping the side form. Effective procedure to decide the removal time of side form can be performed by applying P type Schmidt hammer.

• Journal of Korean Society of Forest Science
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• v.105 no.4
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• pp.422-428
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• 2016

Ginkgo (Ginkgo biloba L.) is one of the most appropriate roadside trees because of a good transplantation nature and ability to grow well in urban environment. Ginkgo is a dioecious species. Sex discrimination of ginkgo is possible through comparing morphological characters of reproductive organs. However, it needs more than about twenty years for reproductive organs to appear after sexual maturity. Until now, ginkgo trees for roadside plantation have been planted without discriminating the sex because ginkgo trees have been usually planted before sexual maturity. Ginkgo nuts from the female ginkgo trees planted along the roadside emit a foul odor, and make much pollution on the streets. Thus in this study a novel SCAR marker (SCAR-GBM) for the early sex discrimination was developed. Primers were developed on the basis of the sequence of male-specific RAPD variants reported previously. False-negative problem of SCAR marker, probably caused by dominant nature, was resolved by using multiplex PCR using primers of both the SCAR-GBM and a universal primer set of atp1 region in mitochondria DNA, which resulted in improved discrimination efficiency. The results showed that DNA bands of 1,039 bp were commonly amplified by the atp1 primer set in male and female trees, and SCAR-GBM markers of 675 bp were specifically amplified only in male trees. Reproducible and specific discrimination of the multiplex PCR was finally confirmed by applying multiple male and female individuals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.366-369
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• 2000

This study was conducted to determine the effect of seeding date on the days and the accumulated temperatures to development stages, leaf emergence, and yield in spring-planted barley. Two barley varieties, Sacheon #6 in spring type (growth habit I) and Saechalssalbori in winter type (growth habit IV), were seeded on four seeding date, Feb. 23, March 4, March 13, and March 24. Growth periods to emergence, heading and maturity were shorten when seeding dates were delayed, except for the heading date of Saechalssalbori (winter type barley)at the later seeding date. The rate of leaf emergence was 0.1915 in a day, and was slightly high when seeding was delayed. The accumulated temperatures were 111-142$^{\circ}C$ for emergence, 683-756$^{\circ}C$ for heading, and 1274-1326$^{\circ}C$ for maturity. In general, the accumulated temperature to heading was higher in Saechalssalbori than in Sacheon #6 because the winter growth habit of Saechalssalbori was not removed perfectly, One-thousand grain weight and yield were reduced by delayed seeding. In order to reduce the yield when barley were planted in spying, it is desirable to select the spring type varieties, and to plant them as early as possible.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.1
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• pp.31-37
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• 1993

To analyze and classify the varietal variation of alkali digestibility in detail, which is closely connected with the gelatinization temperature and physical characteristics of cooked rice, the patterns of alkali decomposition changed along the alkali concentration were investigated for thirty three Korean leading rice cultivars and new breeding lines(japonica : 25, Tongil-type:8) including five glutinous rice. Principal component analysis was used to condense the information and to classify rice materials according to decomposed reaction pattern at several levels of potassium hydroxide(KOH) concentration. Thirty three rice varieties were classified largely into four groups by the distribution on the plane of upper two principal component scores which contained above 92% of total informations. Group I was consisted of one variety, Dobongbyeo, which owned almost same strong resistance to alkali digestion at the range of 0.8% to 1.6% KOH solutions. Group II included three japonica and Tongil-type glutinous rice varieties, which revealed medium alkali digestion value(ADV) at 1.4% KOH solution and intermediate change in ADV from 0.8% to 1.6% KOH solutions. Most of Tongil-type and early-maturity japonica rice, which exhibited medium-high ADV at 1.4% of KOH concentration and large ADV difference between low and high alkali solutions, were contained in Group III. Group N included most of medium or medium-late-maturity japonica, which showed high ADV at 1.4% KOH and medium or intermediate-high ADV change between low and high alkali solutions. The 1st principal component indicated the average index of ADV through 0.8-1.6% KOH solutions and the 2nd principal component pointed out the factor related with ADV difference between low and high alkali solutions or regression coefficients of ADV change along with the KOH concentrations.

• Korean Journal of Plant Resources
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• v.33 no.1
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• pp.50-61
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• 2020

Pigeon pea (Cajanus cajan) is an important legume species that produces seeds that are rich in phenolic compounds and dietary nutrients. The aim of the present study was to evaluate the agricultural characters, phenolic and nutritional contents, and antioxidant capacities of seeds from 82 pigeon pea germplasms cultivated in the Republic of Korea. The accessions exhibited compact (24.39%), semi-spreading (74.39%), or spreading (1.22%) growth habits and determinate (89.02%), indeterminate (8.54%), or semi-determinate (2.44%) flowering patterns. Days to 75% maturity ranged from 30 to 72 d, and yield per plant ranged from 6.00 to 148.60 g. Meanwhile, total phenolic, crude protein, crude fiber, and dietary fiber contents ranged from 16.42 ± 0.62 to 29.67 ± 0.43 mg gallic acid equivalent per g of dried extract, from 16.76 ± 6.74% to 22.61 ± 0.05%, from 4.70 ± 0.24 to 8.63 ± 0.02%, and from 12.98 ± 0.71 to 33.19 ± 1.50%, respectively. In addition, DPPH radical-scavenging capacity ranged from 1.61 ± 0.10 to 16.04 ± 2.30 mg ascorbic acid equivalent per g of dried extract, and Trolox equivalent antioxidant capacity ranged from 3.03 ± 0.86 to 42.24 ± 0.72 mg Trolox equivalent per g of dried extract. Phenolic content was correlated with both DPPH radical-scavenging capacity (r = 0.63) and Trolox equivalent antioxidant capacity (r = 0.29). Nine accessions (IT170290, IT170291, IT170270, IT170276, IT170379, IT170386, IT170388, IT170418, and IT170340) exhibited early maturity, compact and erect growth habits, and above average antioxidant activities and phenolic and protein contents. In addition, accessions IT170290 and IT170291 were especially promising pigeon pea germplasms to grow, owing to various favorable characteristics (e.g., high yield and dietary fiber content). Hence, these accessions could be useful cultivars to the Republic of Korea if considered in future agricultural systems.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.9-17
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• 2003

The gonad index (GI), reproductive cycle with gonad developmental phases, first sexual maturity and the sex ratio of the jedo venus, Protothaca jedensis, on the coastal waters of Boryeong, Korea were investigated by histological study. Samples were collected from the subtidal zone of Boryeong, Korea from January to December, 1999. Monthly changes in the gonad index in femal and male clams gradually increased from February and reached the maximum in May, and then the values rapidly decreased from June and reached the minimum in November as seen in variations of the reproductive cycle. The spawning period of this species was once a year between May and July, there was a spawning peak between June and July when seawater temperature was over 20$^{\circ}C$. The reproductive cycle of this species in female and male clams can be classified into five successive stages: early active stage (December to March), late active stage (February to June), ripe stage (April to July), partially spawned stage (May to July) and spent/inactive stage (July to January). Percentages of first sexual maturity of female and male clams of 30.1-35.0 mm in shell length were 52.6% and 60.0%, respectively, and 100% for the clams over 45.1 mm in shell length. The sex ratio of individuals > 30.1 mm in shell length was 1:1 (X$^2$ = 0.40, p > 0.05).