• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.182-191
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• 2020

A field test and a phytotron study were performed over two years to examine whether rice varieties originated from higher altitude areas have lower optimum grain filling temperatures for yield improvement than the varieties from South Korea. Three varieties originated from North Korea and three varieties from northern China were compared to the same number of varieties from South Korea. In a field study, the optimum grain filling temperatures over 40 days after heading were 22.6 - 23.0℃, 21.5 - 22.3℃, and 21.5 - 23.6℃ for the varieties from North Korea, northern China, and South Korea, respectively, resulting in no significant difference among varietal groups. Meanwhile, the heading dates of the early maturing varieties from North Korea and China were 7 - 12 days earlier than that of the early maturing Odae variety from South Korea during the first transplant of 2017. The phytotron study, in which different temperature regimes were imposed from flowering/fertilization to harvest with constant daily mean temperatures, revealed that milled rice weight did not decrease under low temperatures, even at 16℃, compared to that at 22℃. At the fourth transplant in the field study, mean temperature lower than 10℃ appeared before rice grains were fully developed, resulting in yield reductions. It was concluded that rice varieties adaptable to high-altitude areas do not have lower optimum grain filling temperatures but, instead, possess shorter growth durations. It was further suggested that the optimum grain filling temperature of rice observed under natural conditions could be attributed to the lowering temperature at the late filling stage under temperate climatic conditions.

• Applied Biological Chemistry
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• v.8
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• pp.95-100
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• 1967

A quantitative study on the mercury residue in the brown rice of "Paldal", a recommended rice variety in Korea, was carried out by changing the date and frequency of application with different forms of organo-mercury fungicide(PMA), which is used for the control of rice blast. The results are summarized follows: 1) Mercury residues were higher with the emulsion formulation(0.21 ppm) than the dust formulation (0.16 ppm) when they were used for the control of leaf blast on July 13. 2) In case when both of the emulsion and dust formulations were used on July 13 and August 13, respectively, the mrecury residues were lower in the treatment on July 13 (0.216 and 0.16 ppm) than in the treatment on August 13 (0.304 and 0.238 ppm). 3) In an emulsion formulation was applied once on August 13, the mercury residue was 0.304 ppm and its application in twice on July 13 and August 13, the residue was counted 0.32 ppm. In case of dust formulation, the residues were observed 0.238 ppm in a single dose and 0.276 ppm in double application. 4) When the fungicide was applied to the rice plant on August 13, the mercury residues in brown rice, rice bran, and stalk and leaves were 0.304, 0.323, and 0.676 ppm, respectively found in the case of emulsion and in the case of dust formulation, they were 0.238, 0.283 and 0.698 ppm, respectively. The mercury residue, in general, were less in the case of dust than in the case of emulsion formulation and lowered by a single treatment than by two times application and it was also less by treating on July 13 than by treating on August 13.

• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.53-63
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• 1978

The object of this study is to clarify the varietal resistance to green leaf-and planthoppers and to evaluate the nature of the resistance to the insects in connection with the antibiosis. This study investigated the reaction of the 46 rice varieties to insects including recommended varieties of Korea. At seedling stage they were infested with second or third instar nymphs. The results were as follows. 1. The body weight of brown planthopper was increased more than 3 times on susceptible rice variety Mankyung at 15 days after infestation but only 2 times on resistant mudgo. 2. The mortaliy of the brown planthopper was significantly different between resistant and susceptible rice plant, showing 74 percents in resistant Mudgo while 31.2 percents in susceptible Mankyung at 15 days after caging. 3. Most of the rice varieties tested showed highly susceptible reaction to brown planthopper except Mudgo, KR 108-243-1 and HR 529-41-3-2 as resistant varieties, and Akamochi, Satominori, IR 24 and IR 8 as moderately susceptible ones. 4. In the test of varietal resistance to white-backed planthhopper, Mudgo, KR 108-243-1, KR 109-154-2 and HR 529-45-2 and HR 529-45-3-2 were resistant, and Suweon #82, Tongil, IR 8, Palkeum, Iri #309, Hokwang and Chukoku #31 were moderatly susceptible. 5. Most of the varieties tested were observed as highly resistant to green rice leafhopper, but Tongil, Suweon 82, IR 24, Milsung and Chukoku #31 were moderatly susceptible. 6. The new bred lines HR 108-243-1 are multi-resistant to brown planthopper, green rice leafhopper and White-backed planthopper, and some others showed moderate susceptibility.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.459-468
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• 2019

Changes in growing periods and productivities of crops under double cropping of potato-rice, potato-soybean and potato-maize, were investigated at the Paddy Experimental Fields in Miryang City from 2015 to 2018. Spring potatoes planted in early March showed a yield of 2.1-2.3 ton/10a and a period of 90 days. In double cropping, growing period of rice, soybean, and maize was about 130, 125 and 115 days, respectively. The potato yield obtained was as much as 616, 330 and 815 kg/10a under double cropping with rice, soybean and maize, respectively. It is beneficial to sow the spring potatoes as early as possible to increase the yield and to secure the growing period of sequential crops. The introduction of summer medium-late variety grain crops into double cropping of spring potato and rice as well as into double cropping of spring potato and soybean/maize, was possible because of no sowing in the fall and plants were able to reach the heading growth stage before the safe heading limit of rice in particular. In the case of maize, the growth period was different according to the change in temperature over the year. The introduction of upland crops such as soybeans and maize instead of rice improved soil physicochemical properties in a short period of time, contributing to the increase of spring potato yields, but there was also a risk of damage by successive cropping for more than three years. Spring potato-maize showed higher yield in terms of starch production, and spring potato-soybean was found to be advantageous for net income.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.17-21
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• 1970

To determine the effects of the silicate and the phosphate on the rice seedlings, 200 grams dry soil of the paddy field taken in the petri dish of 15cm diameter were treated with three levels of silicate(wollastonite) and phosphate. And the same amounts of nitrogen and potash were added constantly to each treated petridish. 100 grains of rice of which variety is Nongrim 25 were sown on each treated petridish simultaneously. After five times continuous culture, the rice plants and the soil were analyzed chemically and the results obtained are summarized as follows: 1. Dry matter weight of the rice seedlings was significantly increased to the increased phosphate absorption, on the other hand that was decreased when the silica absorption was increased. 2. The higher the available phosphate content in the soil after the experiments, the lower the silica content as well as absorption by the plant, and the $SiO_2/P_2O_5$ ratio in the plant was significantly decreased. 3. By the wollastonite application, the available silica, the exchangeable calcium in the soil after the experiment, and the silica content as well as silica absorption and $SiO_2/P_2O_5$ ratio in the rice plant was significantly increased. 4. Higher correlation coefficient was obtained between the exchangeable calcium amount and the silica content or silica/phosphate ratio in the rice plant than the available silica content in soil itself. 5. It is possible to control the silica/phosphate ratio in plant by the control of the silica/phosphate ratio in soil. 6. The relation between the silica/phosphate ratio in plant (y) and the available silica/phosphate ratio in soil (x) was $y=0.665+1.420x-0.0825x^2$ and the goodness of fit(r) was 82%.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.526-532
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• 2017

Development, survival, and reproduction of brown planthopper (BPH) Nilaparvata lugens $St{\aa}l$ (Hemiptera: Delphacidae), were studied in laboratory at $25{\pm}2^{\circ}C$, $65{\pm}5%$ RH and a 16L : 8D hours photoperiodism on five rice cultivars of: Dongjin 1ho, Chungchungbyeo, Jangseongbyeo, Chinnongbyeo and Jungmo 1045. BPH nymphs successfully survived on all rice cultivars, although survival rate was lowest on Jangseongbyeo (36.0%). Developmental time of immature stages ranged from $11.7{\pm}0.59d$ on Jungmo 1045 to $12.8{\pm}0.59d$ on Chinnongbyeo. Reproductive period and female longevity were longest on Dongjin 1ho, Chinnongbyeo and Jungmo 1045 while highest fecundity of N. lugens being observed on these three rice cultivars. Highest and lowest net reproductive rates were calculated on rice cultivars, Jungmo 1045 and Jangseongbyeo, respectively. Mean generation time was the longest on rice cultivar Dongjin 1ho. Respective descending order of intrinsic rates of population increase were on Jungmo 1045, Chinnongbyeo, Dongjin 1ho, Chungchungbyeo and Jangseongbyeo. These population parameters showed that N. lugens can successfully survive and reproduce on Chinnongbyeo and Jungmo 1045.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.210-219
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• 2021

In recent years, air temperature has been increasing rapidly compared to the 1980s because of global warming. This increase in temperature reduces the yield and quality of rice; therefore, measures are needed to prevent such effects and ensure food security. The early maturing type (EMT) of rice is mainly cultivated in the central northern mid-mountainous area (CNMA). This study was conducted to shift the transplanting date of EMT and to examine the adaptability of the mid-maturing type (MMT) or mid-late maturing type (MLMT) in the Jecheon region of the CNMA to address global warming. The air temperature increased by 0.7-0.9℃ in the 2010s, compared to that in the 1980s, and was similar to other decades during the ripening period. Over the past 35 years, considering rice quality, the heading date of the Odae variety has arrived sooner by approximately 10 days, the ripened grain ratio has increased by more than 10%, and the thousand grain weight; however, the mean temperature at 40 days after heading has increased by more than 2℃. The late marginal heading date in the Jecheon region was determined as August 11 based on the accumulated temperature of 880℃ and August 15 based on 840℃ for 40 days after heading. According to different transplanting dates, milled rice yield per 10 a was the highest at 567 kg with June 10 in EMT, 595 kg with June 10 in MMT, and 572 kg with May 30 in MLMT. Considering the late marginal heading date, rice yield, and quality, the optimum transplanting date was June 15 in EMT, June 5 in MMT, and May 30 in MLMT in the Jecheon region of CNMA. Owing to global warming, MMT and MLMT are expected to be reliably cultivated in the CNMA.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.177-181
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• 2009

'Pyeongwon' is a new japonica rice cultivar which is developed from a cross between Jinbu19 and Samjiyeon4 from North Korea by the rice breeding team of National Institute of Crop Science, RDA. Pyeongwon has about 107 days duration from seeding to heading in mid-northen plain, alpine, north-eastern coastal and southern alpine areas. It has about 67 cm culm length and tolerance to lodging. Pyeongwon has 13 tillers per hill and 82 spikelets per panicle. It showed tolerance to heading delay and spikelet sterility due to cold treatment similar to Odaebyeo. It also showed slow leaf senescence and moderate tolerance to viviparous germination during the ripening stage. Pyeongwon has resistance to blast disease but susceptible to stripe virus and brown planthopper. Milled rice of Pyeongwon has translucent kernels, relatively clear non-glutinous endosperm and medium short grain. It is characterized as a low gelatinization temperature and slightly lower amylose content (17.1%) variety compared to Odaebyeo (19.5%) and has good palatability of cooked rice. The milled rice yield performance of this cultivar was about 5.28 MT/ha by ordinary culture in local adaptability test for three years. This cultivar may be highly adaptable to the mid-northen plain, alpine, north-eastern coastal and southern alpine areas of Korea.

• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.395-403
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• 2019

Rice blast caused by the fungus Magnaporthe grisea (anamorphic: Pyricularia oryzae) is an important disease in rice and development of resistant varieties to blast is one of the most important goals in rice breeding programs. A japonica rice variety, Palgong, has shown resistance to the Korean blast pathogen since it was developed in 1996. Nine blast resistance quantitative trait loci (QTLs) in Palgong alleles were identified on chromosomes 2, 4, 7, and 11. Four QTLs of qBn2.3, qBn4.2, qBn11.1, and qBn11.2 explained 28-56.7% of total phenotypic variation, while five QTLs of qBn2.2, qBn2.4, qBn4.1, qBn7.1, and qBn7.2 explained 9.7-18.8%. In a previous study, one to four resistance genes were located on the loci qBn2.2, qBn2.3, qBn4.2, qBn11.1, and qBn11.2, however, resistance genes were not located on the loci qBn2.4, qBn4.1, and qBn7.1. A major QTL, qBn11.2, explaining 56.7% of total phenotypic variation was related to the durable resistance of Palgong. Additionally, rice stripe virus resistance of Palgong was assumed to be based on the Stvb-i gene, which is located on a major QTL qBn11.2.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.3
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• pp.207-216
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• 2004

This study was carried out to select the promising forage crops for forage production in paddy field of NLRI, RDA, Suwon from 1999 to 2001. The species of forage crop used in this experiment were barley(3 varieties), wheat(2), rye(3) and Italian ryegrass(IRG, 3). Stages of heading, milk and yellow ripe of barley were 1 May, middle May and late May, respectively. In milk to yellow ripe stage, dry matter(DM) and total digestible nutrient(TDN) yield of barley were $7.30{\sim}9.58$ MT and $4.75{\sim}6.24$ MT per ha, and Albori was the most promising variety among the barley. The growth of wheat was a little late compared to that of barley. but it seemed to be crop having higher forage yield and nutritive value. In milk to yellow stage, DM and TDN yield of wheat were $8.17{\sim}10.82$ MT and $5.33{\sim}7.31$ MT per ha. Heading stage of rye was 27 to 29 April, and it seemed to be suitable for harvest at heading to flowering stage because of heavy lodging after flowering. In flowering stage, DM and TDN yield of rye were 10.18 and 6.03 MT per ha. Heading stage of early maturing IRG was 7 May and it seemed to be good for harvest at flowering stage of middle May in cropping system. In flowering stage, DM and TDN yield of early type IRG were 4.48 and 2.96 MT per ha. The results demonstrated that the promising forage crops for forage production in paddy. field were rye and barley(Albori) in Middle region, and rye harvesting at early May was recommended when considered middle May of rice transplanting period, and rye and barley considered late May of rice planting period. Also early maturing and high yielding IRG variety was strongly needed.