• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.550-556
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• 1992

Performance of a rice breeding line, Milyang 95 was evaluated at four cultural methods, direct seeding on dry soil covered by making ridges (DS ridged), direct seeding on dry soil covered by rotortilling (DS rotary), direct seeding on flooded soil (FS), and machine transplanting (MT). Days from seeding to emergence in both DS ridged and DS rotary was 15 days. The number of seedlings at DS ridged and DS rotary was lower than that at FS. Heading was earliest at MT, latest at DS rotary and DS ridged, and that at FS was between them. Days from seeding to heading was 115 days at MT, 94-95 days at DS ridged and DS rotary, and 87 days at FS. Lodging index was similar among the cultural methods and lodging was not occurred in the field although fresh weight of tillers and breaking strength at MT were higher than those of direct seedings. Yield and most of yield components were similar among the cultural methods although the number of spikelets per panicle at MT was higher and 1,000 grain weight at FS was lower compared to other cultural methods. Grain appearance (rusty, chalky abortive rice), protein and amylose contents and alkali digestibility were observed.

• Korean Journal of Plant Resources
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• v.20 no.4
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• pp.331-335
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• 2007

This study was conducted to investigate the soil mulching effect on bolting and growth of Angelica koreana Max. The bolting ratio were 8.4% of non-mulching, 11.4% of black polyethylene film, 13.6% of transparent polyethylene film, 6.4% of rice-straw mulching. The mulching of polyethylene film induced higher bolting response than other materials. The radical leaf length, the number of leaf and crown in black P.E. film mulched were all higher than those of non-mulching and rice-straw mulching. The yield of the underground part of P.E film mulching was higher than non-mulching and rice-straw mulching. Comparing with other treatments, the dry root yield of black P.E. film mulching showed the most.

• The Korean Journal of Zoology
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• v.24 no.3
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• pp.151-161
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• 1981

The field studies on the seasonal population prevalences of the vector mosquito larvae and other aquatic invertebrates were weekly carried out in the rice fields located in front of a village of Kwangtan-samri, Byeogje-myeon, Goyang-gun, Gyeonggido throughout mosquito breeding season (June-September) in 1980, and the results are as follows. The population of C. tritaeniorhynchus larvae increased soon after heavy rainfall, and decreased to some extent during the period of the insecticide application. The seasonal prevalence of A. sinensis was rather stable, not being affected by insecticide pressure at all. The population densities of other aquatic invertebrates in rice fields were seriously suppressed by the pesticide application, and their recovery was not as same as the previous level or not at all: (1) The populations of Odonata and Ephemeroptera nymphs were drastically decreased by the first application of insecticides and never recovered through out season. (2) Coleoptera seemed very susceptible to the insecticide application, as densities were markedly decreased whenever the insecticides were applied. (3) The high density of Hemiptera shown in early June were decreased sharply after the first application of pesticides, and thereasfter, some degree of recovery was shown, but suppressed by successive each application of pesticides. (4) A native species of planaria was exceptionally not influenced by the insecticide pressure, and two peaks of the density were appeared during the heavy rainfall.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.181-186
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• 2008

To assess the potential as biofortified rice varieties, new endosperm and grain mutant lines were selected from $M_4$ generation seeds of the rice cultivar Shindongjin, which were either $\gamma$-irradiated or treated with N-methyl-N-nitrosourea(MNU) and lipid, sugar, and tocopherol content were analyzed. Amylose content in non-waxy mutants ranged from 8.8% in SM-4, a dull-type mutant, to 29.5% in SM-51, compared to 18.9% in the parental variety, Shindongjin. SM-23, a floury-type mutant, contained 0.09 ${\mu}g/g$ $\alpha$-tocopherol(40.9% of total tocopherol), was three times higher than in the parental variety. SM-32, a giant embryo-type mutant, had a 2.2-fold higher total tocopherol content, 2.1-fold higher $\alpha$-tocopherol, and 5.5-fold higher $\delta$-tocopherol content(47.3% of total tocopherol) than the parental variety(0.13 ${\mu}g/g$). Total free sugar content was elevated in all selected mutants and 1.2-8.6 times higher than in the parental variety(11.38 ${\mu}g/g$). These increased sugar levels were due to increase in sucrose concentration. SM-23(floury-type mutant) and SM-51(high amylose-type mutant) had 4.6 and 7.0 times more sugar, respectively, than the parental variety(11.38 ${\mu}g/g$). With relatively high concentrations, most mutants showed elevated fatty acid content in the SM 32(giant embryo-type) and SM-51(high amylose-type) mutants, at 124.56 and 89.59 mg/g, respectively. All selected mutants displayed valuable characteristics for the development of new varieties in rice-breeding programs.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.256-262
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• 2018

Multiple temporal scale can be a useful method to understand population dynamics in ecosystem. The multi-temporal scale approach for population dynamics has rarely been researched till lately. This study was carried out to identify the factors in affecting the population dynamics of herons, including Eastern Cattle Egret (Bubulcus coromadus), Grey Heron (Ardea cinerea), Great Egret (A. alba), Intermediate Egret (Egretta intermedia) and Little Egret (E. garzetta), at rice paddy fields of Seokmun-myeon in the city of Dangjin, South Chungcheong Province during the main breeding periods from 2014 to 2017. We identified the population dynamics of herons at different time interval (day and month) using the unmanned monitoring system. As a result, monthly population dynamics was mostly affected by time, mean temperature and mean precipitation, whereas daily population dynamics was affected by mean temperature and habitat types. The results suggest that there are differences in the factors affecting the population dynamics of herons according to the time scale.

• 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.62 no.2
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• pp.87-95
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• 2017

The increase in the frequency of occurrence of abnormal weather could include severe rainfall, which could cause rice submergence during the ripening stage. This experiment was conducted to clarify the effects of submergence during the ripening period on yield and quality of rice. The flooding treatment was conducted at 7 and 14 days after heading. Flooding conditions were created with two conditions, flag leaf exposed and overhead flooding, and each condition was divided into two conditions according to water quality-clear and muddy. Although the yield decrease was more severe at 7 days after heading because of the decrease in the ripening ratio, the head rice ratio was more affected at 14 days after heading because of the increase in the chalky kernel ratio. The maximum quantum yield (Fv/Fm), which indicates the photosynthetic efficiency, did not differ before and after the flooding treatment until flooding continued for 4 days. In addition, stem elongation occurred because of flooding as an avoidance mechanism in japonica rice. This phenomenon was expected to decrease the supply of assimilation products to the spikelet (sink). Overall, it was suggested that additional experiments should be conducted examining the change in the starch synthesis mechanism and transfer of assimilate products resulting from submergence, for development of cultivation techniques corresponding to submergence and breeding of varieties with submergence tolerance characteristics.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.3
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• pp.193-202
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• 2012

'Joseong', a winter forage triticale cultivar (X Triticosecale Wittmack), was developed by the breeding team at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2010. The cultivar 'Joseong' was selected from the cross FAHAD_5/RHINO1R.1D 5+10 5D'5B'//FAHAD_5 by CIMMYT (Mexico) in 1992. Subsequent generations were handled in pedigree selection program at Mexico from 1993 to 1998, and a line 'CTSS92Y-A-4Y-0M-5Y-0B' was selected for earliness and good agronomic characteristics. After preliminary and advance yield test in Korea for 2 years, the line designated as a line name of 'Iksan26'. The 'Iksan26' was subsequently evaluated for earliness and forage yield in 7 different locations such as Jeju, Iksan, Cheongwon, Yesan, Naju, Daegu, and Jinju from 2008 to 2010 and finally named as 'Joseong'. The cultivar 'Joseong' has characteristics of dark green leaf, yellow culm and spike, and large grain of yellowish brown color. The heading date of cultivar 'Joseong' was April 24, which was 5 days earlier than that of check cultivar 'Shinyoung'. It showed better tolerance or resistance to lodging, wet injury, powdery mildew, and leaf rust than those of the check cultivar 'Shinyoung'. The average forage dry matter yield of cultivar 'Joseong' at milk-ripe stage was 14.5 MT $ha^{-1}$, which was lower than 16.5 MT $ha^{-1}$ of the check cultivar 'Shinyoung'. The silage quality of 'Joseong' (5.3%) was lower to the check cultivar 'Shinyoung' (6.0%) in crude protein content, while was 2.1% superior to the check cultivar 'Shinyoung' (61.9%) in TDN (total digestible nutrients). It showed 5.1 MT $ha^{-1}$ of grain yield, which was 40% higher than that of the check cultivar 'Shinyoung' (3.65 MT $ha^{-1}$). This cultivar is recommended for fall sowing crop in the area where daily minimum mean temperatures are averaged higher than $-10^{\circ}C$ in January, and as a winter crop using whole crop forage before planting rice in around Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.4
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• pp.304-310
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• 2017

This study was conducted over a 3-year period from 2013 to 2015 in the mid-northern inland, Cheolweon, Korea, to investigate changes in flowering date, daily mean temperature during grain filling, and yield characteristics affected by transplanting date in an early-maturing rice variety, 'Joun'. Thirty-day-old seedlings were transplanted at four different dates at 15-day interval from May 5 to June 19. Flowering dates were July 16, July 21, July 31, and August 14 when transplanting was performed on May 5, May 20, June 4, and June 19, respectively. Late transplanting resulted in higher daily mean temperature before flowering but late-transplanted rice required fewer days and lower cumulative temperature to reach flowering from transplanting. As transplanting was delayed, daily mean temperature for 40 days after flowering decreased, whereas daily sunshine hours for the same period increased, with a temperature of $24.8^{\circ}C$ and sunshine for 5.8 hours being recorded at the transplanting on May 5, and with a temperature of $21.0^{\circ}C$ and sunshine for 7.7 hours at the transplanting on June 19. With late transplanting, panicles per square meter significantly decreased, whereas spikelets per panicle showed an increasing trend. Regression analysis showed that maximum head rice yield was attained from the transplanting on May 18, for which the flowering date was July 21, and daily mean temperature for 40 days from that flowering date was $24.6^{\circ}C$. A decrease in head rice yield by 5% and 10% of the maximum was observed for rice transplanted on June 6 and June 15, which resulted in flowering dates of August 2 and August 11, respectively, and the daily mean temperatures for 40 days from flowering were 23.2 and $21.7^{\circ}C$, respectively. Therefore, in mid-northern inland, it is recommended to transplant 'Joun' on May 18 to induce flowering on July 21, when grain filling is subjected to a daily mean temperature of $24.6^{\circ}C$ during active filling stage.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.3
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• pp.133-144
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• 2022

This study was conducted to investigate the cultivation period, adaptive genetic resources, growth and development patterns, and water consumption for rice cultivation in the desert environment of United Arab Emirates (UAE). R esearch on rice cultivation in the desert environment is expected to contribute to resolving food shortages caused by climate change and water scarcity. It was found that the optimal cultivation period of rice was from late November to late April of the following year during which the low temperature occurred at the vegetative growth stage of rice in the UAE. Asemi and FL478 were selected to be candidate cultivars for temperature and day-length conditions in the desert areas as a result of pre-testing genetic resources under reclaimed soil and artificial meteorological conditions. In the desert environment in the UAE, FL478 died before harvest due to the etiolation and poor growth in the early stage of growth. In contrast, Asemi overcame the etiolation in the early stage of growth, which allowed for harvest. The vegetative growth phases of Asemi were from early December to early March of the following year whereas its reproductive growth and ripening phases were from early March to late March and from late March to late April, respectively. The yield of milled rice for Asemi was 763kg/10a in the UAE, which was about 41.8% higher than that in Korea. Such an outcome was likely due to the abundant solar radiation during the reproductive growth and grain filling periods. On the other hand, water consumption during the cultivation period in the UAE was 2,619 ton/10a, which was about three times higher than that in Korea. These results suggest that irrigation technology and development of cultivation methods would be needed to minimize water consumption, which would make it economically viable to grow rice in the UAE. In addition, select on of genetic resources for the UAE desert environments such as minimum etiolation in the early stages of growth would be merited further studies, which would promote stable rice cultivation in the arid conditions.