• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.379-388
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• 2011

The mechanism by which gonadotropin-releasing hormone (GnRH) and dopamine (DA) control gonadotropin (GTH) release was studied in male and female rainbow trout using cultured pituitary cells obtained at different reproductive stages. The mechanisms of follicle-stimulating hormone (FSH) release by GnRH and DA could not be determined yet. However, basal and salmon-type GnRH (sGnRH)- or chicken-II-type GnRH (cGnRH-II)- induced luteinizing hormone (LH) release increased with gonadal maturation in both sexes. LH release activity was higher after sGnRH stimulation than cGnRH-II stimulation at maturing stages in both sexes. The GnRH antagonist ([Ac-3, 4-dehydro-$Pro^1$, D-p-F-$Phe^2$, D-$Trp^{3,6}$] GnRH) suppressed LH release by sGnRH stimulation in a dose-dependent manner, although the effect was weak in maturing fish. The role of DA as a GTH-release inhibitory factor differs during the reproductive cycle: the inhibition of sGnRH-stimulated LH release by DA was stronger in immature fish than in maturing, ovulating, or spermiated fish. DA did not completely inhibit sGnRH-stimulated LH release, and DA alone did not alter basal LH release. Relatively high doses ($10^{-6}$ or $10^{-5}M$) of domperidone (DOM, a DA D2 antagonist) increased LH release, which did not change with reproductive stage in either sex. The potency of DOM to enhance sGnRH-stimulated LH release was higher in maturing and ovulated fish than in immature fish. These data suggest that LH release from the pituitary gland is controlled by dual neuroendocrine mechanisms by GnRH and DA in rainbow trout, as has been reported in other teleosts. The mechanism of control of FSH release, however, remains unknown.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.215-222
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• 1994

This experiment was conducted to find out the response of orchardgrass (Dactylis glorneruta L.) varieties to grazing at the condition of monocultures and mixed pastures on the field of Livestock Experiment Station at Suwon from Sep. 1989 to Oct. 1991. The varieties of orchardgrass used in this experiment were Potomac, Hallmark and Syn. No. 2 as a early maturing type, and Lidacta, Rancho and Syn. No. 10 as a late maturing type. The results obtained were as follows: 1. Herbage utilization of mixture with Hallmark variety(T2) was the highest as 78.2% and that with Rancho variety(T5) was the lowest as 70.2%. but there was no difference(P>0.05). Mixtures with early maturing varieties(T1, T2 and T3) were higher as 77.4% than those with late varieties(T4, T5 and T6) as 72.9% in herbage utilization. In monocultures Rancho variety(T5) was the highest as 68.6% and Lidacta variety(T4) was the lowest as 58.8%, and mixtures with early maturing varieties(T1, T2 and T3) as 66.6% were higher than those of late(T1, 72 and 73) as 64.6%. 2. The content of crude protein of 6 mixed pastures ranged from 19.7% to 22.8%, and those of ether extracts, crude fiber, crude ash and nitrogen free extract were 6.6 to 7.5%, 24.9 to 26.2'76, 1 1.5 to 1 1.9% and 33.6-35.4 8, respectively, But there were not different significantly(P>0.05). In monocultures, significant difference by variety was observed in crude protein content(P<0.05). 3. In botanical composition, there was just a little different among 6 mixtures, having 90% or more in grass percentage. The percentages of each orchardgrass varieties were decreased, but those of perennial ryegrasses were increased as grazing sesson was progressed in all treatment.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.206-214
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• 1994

This experiment was conducted to find out the response of orchardgrass (Dactylis glomrrata L.) varieties to grazing at the condition of monocultures and mixed pastures on the field of Livestock Experiment Station at Suwon from Sep. 1989 to Oct. 1991. The varieties of orchardgrass used in this experiment were Potomac, Hallmark and Syn. No. 2 as a early maturing type, and Lidacta, Rancho and Syn. No. 10 as a late maturing type. The results obtained were as follows: I. Heading date of early maturing varieties among orchardgrass like as Potomac, Hallmark and Syn. 2 ranged from May 9 to May 14. Otherwise those of late varieties(Lidacta Rancho and Syn. 10) were between May 21 to May 25. Leaf types of early varieties were shown erect, those of late varieties were erect or semi-erect. 2. In dry matter production per ha, mixture with Rancho variety(T5) was the highest as 7.818 kg and mixture with Hallmark(T2) was the lowest as 7,013 kg. But there was not significantly different(P>0.05) among mixtures. While in monocultures, Syn. 10 variety was the highest(6.626 kglha) and Lidacta was Iowest(5,775 kg). But no difference was found(P>0.05). 3. In mean grass height after grazing, mixtures with early maturing types were higher as 9.8 cm than that of late (8.8cm), and early types were higher as 10.5cm than that of late(9.4cm) in monocultures. But there was no significant difference both mixtures and monocultures.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.259-267
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• 2010

This study was performed at Rice and Winter Cereal Crops Department of NICS during 2007 and 2008 to investigate the characteristics of rice leaf emergence and to obtain basic data which can be used for rice growth simulation model by which we can forecast rice growth stage and heading date accurately under different cultivars, transplanting date, and climatic conditions. To confirm leaf emergence rate according to rice maturing ecotype, we surveyed the leaf emergence rate and heading date of Unkwangbyeo, Hwayoungbyeo and Nampyeongbyeo which are early maturing, medium maturing and medium-late maturing cultivars, respectively, according to seedling raising duration and transplanting time. When seedling duration was 15 days, the growth duration between transplanting time and completion of flag leaf emergence on main culm were 51.5~78.3 days in Unkwangbyeo, 55.3~87.9 days in Hwayoungbyeo and 58.4~98.4 days in Nampyeongbyeo, respectively. When seedling duration was 30 days, they were 50.1~75.5 days in Unkwangbyeo, 52.4~84.7 days in Hwayoungbyeo and 56.4~93.8 days in Nampyeongbyeo, respectively. As transplanting time delayed, the emerged leaf number after transplanting decreased in all rice cultivars. The cumulative temperature between transplanting time to completion of flag leaf elongation on main culm were $1,281^{\circ}C{\sim}1,650^{\circ}C$ in Unkwangbyeo, $1,344^{\circ}C{\sim}1,891^{\circ}C$ in Hwayoungbyeo and $1,454^{\circ}C{\sim}2,173^{\circ}C$ in Nampyeongbyeo, respectively. Leaf emergence rate on main culm were precisely represented by equation, y = $y_0$ + a / [1 + exp( - (x - $x_0$) / b)]^c, when we used daily mean temperature as variable.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.123-127
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• 2002

In order to obtain basic informations for selecting early maturing rice varieties which is suitable for early cropping before Alisma plantago in the southern part of Korea. Eleven rice varieties were grown from May to September in 1999∼2001 at Sunchon Youngieon Experiment Field and yield components and yield of plants were investingated. Early maturing rice cv. Jinbubyeo showed higher rough rice yield than any other varieties used in the experiment. It showed high yield components, culm length, panicle length, number of panicles per plant, number of spikelets per panicle and ratio of ripened grains. therefore, it was concluded that Jinbubyeo was the most suitable variety with high yield for the cultivation before Alisma plantago at the southern part of Korea. The heritability of culm length number of spikelets per panicle and rough rice yield were high and that of panicle length number of panicle per plant, ratio of ripened grain and 1,000 grain wt. of milled rice were low. The rough rice yield showed highly significant positive correlations with culm length, panicle length, number of spikelets per panicles and ratio of ripened grains.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.232-239
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• 1989

Three types of Korean strawberries, Gardian cultivated in vinyl house, Gardian cultivated on the field and Bogyo, at early variety, on the field were harvested after $10{\sim}34$ days from falling of flowers to investigate the chemical changes of fruits during maturing. The initial pH range after 10 days from falling of flowers was $4.13{\sim}4.28$, which was decreased to $3.40{\sim}3.49$ with maturing. The total acid was steadily increased for 26 days and then decreased thereafter. Vitamin C, not detected until 14 days, was gradually increased to $15.83{\sim}24.90mg%$ in 34 days. Reducing sugar content was increased for 24 days and then decreased, while total sugar, glucose and fructose were generally increased during maturing. Xylose was detected a little. For minerals, potassium was measured the highest value, followed by magnessium, and sodium. A trace amount of manganese, zinc and copper were detected. The strawberries had the content range of $6.00{\sim}24.60mg%$ of methyl alcohol and $6.00{\sim}24.40mg%$ of ethyl alcohol.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.291-294
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• 2008

Amylogram properties such as peak viscosity, hot viscosity, cool viscosity, breakdown, pasting consistency and setback were investigated by the Rapid Visco Analyzer and interpreted by the relationship among amylogram properties according to the varietal groups classified by the rapidity of grain filling (RGF) which was calculated by the percentage of grain weight at 15 days after heading to 40 days after heading. The 164 rice recombinant inbred lines from the cross of Milyang23 and Gihobyeo were used to get the basic information regarding the amylogram properties. The used recombinant inbred lines could be grouped into 4 varietal groups such as slow maturing (less than 40% of RGF), mid-slow maturing (41-60% of RGF),mid-fast maturing (61-80% of RGF), and fast maturing (more than 81% of RGF) groups based on the RGF. The peak viscosity and setback showed regular tendency according to the varietal groups classified by the RGF. Positive significant correlations were found between pasting consistency and setback, however negative significant correlations were found between breakdown and setback in all varietal groups.

• Korean Journal of Breeding Science
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• v.40 no.2
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• pp.184-187
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• 2008

A new early maturing satsuma mandarin (Citrus unshiu Marc.) 'Haryejosaeng' was developed as a nucellar seedling selection of 'Tachima Wase' (C. unshiu Marc.) that was crossed with C. natsudaidai Hayata at the National Institute of Subtropical Agriculture in Jeju island in 1992. The 'Jegam ga No. 2', a first selection from the seedlings fruited in 2001 was finally named "Haryejosaeng" through field evaluation trials at three locations in Jeju island from 2003 to 2004. 'Haryejosaeng' produces seedless fruit maturing in early November, and has higher soluble solids and lower acidity than 'Miyagawa Wase', the leading early-maturing satsuma mandarin cultivar in Jeju island. Fruit weight is moderate at about 80~90 g and its shape is compressed-oblate globose with a light orange color. The rind thickness of about 2 mm provides easy peeling. The flesh shows light orange colored and contains 10 to 11 Brix and 1 to 1.1% acidity when mature. Tree shows vigorous growth and spreading thornless twigs. Alternate bearing is similar to 'Miyagawa Wase'. 'Haryejosaeng' is susceptible to citrus scab disease and melanose, but resistant to citrus canker.

• Korean Journal of Plant Resources
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• v.35 no.6
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• pp.785-795
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• 2022

Traditional germplasms are unsuitable for mechanized production, limiting adzuki bean production. The creation of cultivars that can be harvested by mechanized means is an urgent task for breeders. The bottom pod height (BPH), lodging resistance, and synchronous maturing of adzuki beans are critical factors for the reduction of losses due to mechanized harvesting. In this study, 14 traits of 806 adzuki bean accessions were analyzed. All growth stages and the yield, lodging score, and synchronous maturing correlated negatively with the BPH. These negative correlations reflect the increased difficulty of breeding to simultaneously satisfy the needs for no lodging, high synchronous maturing rates, BPHs > 10 cm, and high yield. We screened three germplasms with no lodging, high synchronous maturing rates, and BPHs > 10 cm that were used as mechanization-adapted breeding material for crossing with high-yield cultivars. Agronomic trait diversity in adzuki beans was also examined in this study. Principal component and cluster analyses were conducted for 806 germplasms resulting in three clusters with the yield and three growth stage traits serving as the main discriminating factors. Cluster 1 included high-yield germplasms with the number of pods per plant and the number of seeds per pod being the major discriminant factors. Cluster 2 included germplasms with long growth periods and large 100-seed weights while cluster 3 contained germplasms with high BPHs. In general, the characteristics that make mechanical harvesting feasible and those assessed in this study could be utilized to choose and enhance adzuki beans production.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.325-325
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• 2022

In order to developing high-quality rice varieties and processing varieties, systematic and stable evaluation of physicochemical properties is required for breeding lines. In this study, we compared the quality characteristics evaluation results of rice breeding lines for cooked rice, special rice, and whole crop silage rice adapted to central plain region (Suwon) in order to use as basic data for future rice variety development. Brown rice length/width ratio, head rice ratio, protein content, amylose content, alkali digestion value(ADV) and Toyo value were analyzed to evaluate the quality characteristics of yield trial lines cultivated in Suwon for four years (2017-2020). Brown rice length/width ratio, head rice ratio, protein content, ADV and Toyo values showed significant differences by year, but there was no significant difference in amylose content (p<0.05), which showed little environmental variation. The head rice ratio and Toyo value showed an increasing trend, while the protein content showed a decreasing trend. However, the protein content was the highest in 2020, which is thought to be owing to little sunlight hours due to heavy rainfall in 2020. The protein content of whole crop silage rice was 8.1%, which was significantly higher than that of other lines (p<0.05). Toyo value of medium-maturing and early-maturing lines were 67.6 and 73.7%, respectively, and the Toyo value of medium-maturing lines was higher than that of the early-maturing lines (p<0.05). In correlation analysis among the quality characteristics of the rice lines for cooked rice, significant positive correlations were detected between Toyo value and head rice ratio, amylose content, ADV, and a negative correlation was observed between Toyo value and protein content (p<0.05).