• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.56-61
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• 2005

This study was carried out to elucidate the proper nitrogen application level considering rice quality in Honam plain area from 2002 to 2004 at the paddy field of Honam Agricultural Research Institute. The rice cultivars tested were Samcheonbyeo (Early maturing one), Hwaseongbyeo (Medium maturing one) and Nampyeongbyeo (Mid-late maturing one). The results are summarized as follows: The higher amount of nitrogen application resulted in greater number of panicle and grain in per unit area, but the rate of ripening and the 1,000-grain weight of brown rice decreased. The protein contents showed a tendency of increase with higher nitrogen level. The head rice yield increased by the higher nitrogen application up to 7 kg/10a for Samcheonbyeo and Hwaseongbyeo, and 9 kg/10a for Nampyeongbyeo respectively. The appropriate nitrogen application amounts, with respect to the yield of head rice, the rate of ripening and the quality of rice were found to be in range of 7 to 9 kg/10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.62-68
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• 2005

The characters associated with the rice quality and the factors as the proper harvesting time of rice were examined from 2002 to 2004 at Iksan in Honam plaine area. The rice cultivars tested were Samcheonbyeo (Early maturing one). Hwaseongbyeo(Medium maturing one) and Nampyeongbyeo(Mid-late maturing one). The ripened grain rates were high when the harvesting dates after heading were between 50 to 55 days,55 to 60 days, and 60 days for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively. The yield of rice were higher when harvested 45 to 50 days, 50 to 55 days, and 55 to 60 days after heading for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo. The highest yields of head rice were obtained when harvested 45 days after heading, 50 days and 55 to 60 days for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo. In conclusion, in Honam plain, taking the head rice production, rice quality level, protein content and palatability of rice into account, the best harvest times were found to be 52 days(accumulated temp. : $1,213^{\circ}C$) after heading, 56 days$(1,221^{\circ}C)$, and 60 days $(1,207^{\circ}C)$, for Samcheonbyeo, Hwaseongbyeo and Nampyeongbyeo, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.413-417
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• 1993

This study was conducted to breed various cytoplasmic genetic male sterile (CGMS) and restorer lines with backgrounds of Korean japonica rice varieties. The CGMS line BT-CMS was crossed with the restorer line AR-3. The fertile $F_1 was emasculated and crossed with the Korean japonica rice varieties of the early maturing Sobaegbyeo, Odaebyeo, Gwanagbyeo and Daeseongbyeo, and of the medium maturing Hwajinbyeo, Paldal, Suwon 224 and Iri 386, and of the late maturing Nagdongbyeo, Palkweng, Hwacheongbyeo and Milyang 97. Each of the three way cross $F_{1S} was segregated into fertile and sterile individuals. The sterile individuals in each cross were discarded and the fertile individuals were emasculated and backcrossed with the Korean japonica rice varieties. The same process was applied from BC$_1$F$_1$ to BC$_4$F$_1$ generation. In the ${BC_4}{F_1}of each cross, the male sterile individual was crossed with the recurrent Korean japonica variety which was maintainer of male sterility. The male sterile lines of ${BC_6}{F_1}were named as Sobaegbyeo R, Odaebyeo R, Gwanagbyeo R, etc. The fertile individuals homozygous in pollen fertility were selected from the ${BC_4}{F_2}generation and named as Sobaegbyeo R, Odaebyeo R, Gwanagbyeo R, etc. Agronomic characteristics of the CGMS, restorer lines with backgrounds of Korean japonica, and the recurrent Korean japonica rice varieties grown in the field condition were compared. Culm length of the CGMS lines tended to be shorter than that of the recurrent parent, however no significant differences in heading date, panicle length and yield component were found among the CGMS, restorer and recurrent lines.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.435-441
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• 2005

This experiment was conducted to identify the proper time of transplanting at Iksan plain area in Honam area from 2002 to 2004. The rice cultivars tested were Samcheonbyeo, Nampyeongbyeo and Hwaseong­byeo. The results are summarized as follows: The number of spikelets were most when transplanted on May 30 in all maturing types at southern plain. The ripened grain rates vary depending on location and transplanting dates. The proper time of transplanting for both of Samcheonbyeo and Nampyeongbyeo was between May 30 to June 9 and May 30 or later for Hwaseongbyeo. The highest head rice yield was obtained when transplanted on June 9 regard­Bess of the maturing types. The optimum transplanting dates according to maturing types with respect to the yield of head rice, ripened grain rates and the quality for both early and medium type was between May 30 to June 19, for mid-late type between May 30 to June 9.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.379-385
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• 2006

This experiment was carried out to investigate the optimum planting density in low fertilizing cultivation of machine transplanting in rice field of Honam Agricultural Research Institute, NICS for $2004{\sim}2005$. Sobibyeo which belongs to medium maturing variety and Nampyeongbyeo which belongs to medium-late maturing variety were transplanted on May 30. In this experiment, there was no significant difference in heading date between planting density and nitrogen fertilization rate, and heading dates were August 8 in Sobibyeo, and August 14 in Nampyeongbyeo respectively. In relation to lodging character, lodging Index was high where the nitrogen fertilization rate and planting density were high. As planting density increases, panicle number per $m^{2}$ increased irrespective of nitrogen fertilization rate. When nitrogen was 6 kg/10a, rice yield of Sobibyeo was more where planting density was 90 hill per $3.3m^{2}$, and that of Nampyeongbyeo was more where planting density was 80 hill per $3.3m^{2}$. When nitrogen was 9 kg/10a, rice yield of Sobibyeo was more where planting density was 100 hill per $3.3m^{2}$, and that of Nampyeongbyeo was more where planting density was 110 hill per $3.3m^{2}$. Head rice rate of brown rice was higher when planting density increased, and was higher at 6 kg/10a nitrogen rate than 9 kg/10a nitrogen rate in all varieties.

• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.504-514
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• 2019

'Yechan' is a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance. It was a derived from a cross between 'Hopum' and 'Iksan537' (cultivar name 'Haepum'). 'Hopum' is a high grain quality mid-late maturing rice cultivar with strong lodging tolerance and 'Haepum' is a high grain quality medium maturing rice cultivar with multiple disease resistance. To shorten the breeding period, another culture method was applied to the F₁ plants. 'Yechan' was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for grain quality, lodging, and disease resistance. The heading date of 'Yechan' was August 14, one day later than that of 'Nampyeong'. 'Yechan' is a cultivar tolerant to lodging and it has short culms. It has multiple disease resistance against rice blast, rice stripe virus, and bacterial blight, including the K3a race, the most virulent race in Korea. The yield of 'Yechan' was similar to that of 'Nampyeong'. 'Yechan' showed excellent grain appearance, superior taste when cooked, and enhanced milling performance; thus, we concluded that it could contribute to the improvement of Korean japonica rice cultivar quality. 'Yechan', a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance, would be suitable for cultivation in the southern plain area in Korea and has been utilized in the breeding programs aimed at enhancing the grain quality and stability for the cultivation of Korean japonica rice (Registration No. 7647).

• Korean Journal of Plant Resources
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• v.22 no.6
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• pp.483-488
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• 2009

The main objective of this breeding program is to develop high yielding, disease resistance and good processing potato cultivar. 'Gui Valley' is a clonal selection resulting from a cross between 'ND2471-8' and 'Cona'. It has medium plant height and light green foliage. 'Gui Valley' has medium flowering habit and light pink flowers. 'Gui Valley' is a medium maturing potato cultivar and tubers are smooth, yellow skin, light yellow flesh, long-oval tuber shape, distinct red eyes with medium depth and medium dormancy. It has high level of tuber uniformity and good keeping quality. 'Gui Valley' demonstrates resistance to potato virus Y (PVY), soft rot, but moderately susceptible to late blight and common scab. It is also resistant to most of the internal and external physiological disorders particularly dehiscence, hollow heart and internal brown spot. The specific gravity of 'Gui Valley' is significantly higher (1.097) than that of 'Shepody' (1.078). 'Gui Valley' has suitable for processing mainly French fries and chips. This cultivar has high level of tuber uniformity and capable of yielding 37.6 $t{\cdot}ha^{-1}$, which is 18.2% higher than the control potato cultivar 'Shepody' under optimum agronomical practices.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.1
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• pp.99-110
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• 1994

One consequence of fertilization in mammals is an increased resistance of the zona pellucida (ZP) to proteases and various chemical reagents. This phenomenon has been called 'zona pellucida hardening' (ZPH), and it is generally accepted that it is caused by the secretory products of cortical granules released by the egg at fertilization. ZP of mouse oocytes maturing in vitro in a chemically defined medium becomes progressively more resistant to solubilization by chymotrypsin ("Spontaneous" ZP hardening). In the present study, it was aimed to find the specificity of spontaneous ZPH in relation to its possible relevance to the cortical reaction and the physiological block to polyspermy. When a maturation inhibitors, cAMP analog(dbcAMP) and phosphodiesterase inhibitor (IBMX) was added to culture medium, it prevent spontaneous ZPH of mouse oocyte during in vitro culture. Thus spontaneous ZPH requires GVBD, since it is prevented by those agents, which inhibit GVBD in vitro. However, culture for 3 hours in the presence of PMA(lOng/ml), a protein kinase C activator, resulted in ZPH without GVBD, thus suggesting that ZPH may be regulated independently apart from the event of GVBD. Pretreatment of mouse oocyte with FBS result in partially inhibitory effect on subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhibitory effect on the spontaneous ZPH, but subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhinbitory effect on the spontaneous ZPII, but had no inhibitory effect on PMA-induced ZPH. Treatment with a microfilament formation blocker(cytochalasin-B) at 1${\mu}g$/ml concentration, resulted in the excellent inhibitory effect on spontaneous ZPH. However cytochalasin-B did not inhibit PMA-induced ZPH. Thus this suggesting that spontaneuse ZPH had a different mechanism from PMA-induced ZPH.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.306-316
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• 2015

An experiment in a controlled environment was conducted to evaluate the genotypic differences of grain yield and yield-related elements of rice under elevated air temperature. Eight rice genotypes included in three maturing group (early, medium, and medium-late maturing group) were grown with 1/5,000 a Wagner pots at four plastic houses that were controlled to the temperature regimes of ambient temperature (AT), $AT+1.5^{\circ}C$, $AT+3.0^{\circ}C$, and $AT+5.0^{\circ}C$ throughout the rice growing season in 2011. Ripened grain ratio and 1000 grain weight showed the most susceptible and tolerant responses to elevated air temperature, respectively. The grain yield reduction was attributable to the sharp decrease of ripened grain ratio. Grain yield was significantly decreased above the treatment of $AT+1.5^{\circ}C$ and $AT+3.0^{\circ}C$ in early maturing group and the others, respectively. Highly correlation to average temperature from heading to 20 days was revealed in yield (r = -0.69), ripened grain ratio (r = -82), fully-filled grain (r = -70), and 1000 grain weight (r = -0.31). The responses of yield and yield-related elements except number of spikelets and panicle to elevated air temperature were fitted to a logistic function. The parameters of logistic function for each elements except grain yield could not be applied to the other varieties. In conclusion, yield and yield-related elements responded differentially to elevated air temperature according to maturity groups and rice varieties. Ongoing global warming is expected to decrease the grain yield not only by decreasing the grain weight but also decreasing the ripened grain ratio in the future. However, the yield reduction would be mitigated by adopting and/or breeding the less sensitive varieties to high temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.494-503
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• 1995

The selection of salt tolerant rice variety needs an effective method in its testing. Salinity of irrigated water, 0.5% at seedling stage, 0.6% at tillering stage, and 0.9% at panicle formation stage were treated to test salt tolerance of rice using 45 cultivars. At tillering stage, salty water irrigation reduced plant height to 22.6% in early maturing rices(EMR), 30.5% in medium maturing rices(MMR), and 20.9% in medium-late maturing rices(MLMR), and also reduced number of tillers to 11.2% in EMR, 36.2% in MMR, and 36.0% in MLMR compared to rices grown in non-salty water irrigation. At panicle formation stage of rice, salty water irrigation affected plant height and tiller numbers that showed varietal differences. As salt tolerant rice cultivars, Daegwangbyeo, Namweonbyeo, Sinseonchalbyeo, Gyehwabyeo, and Daeyabyeo were selected. Jinbubyeo, Donghaebyeo, and Tamjinbyeo were weak in salty water irrigation.