• 한국식물병리학회지
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• 제13권2호
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• pp.79-84
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• 1997

Incidence of rice blast on new rice cultivars and elite lines was observed from 194 to 1996 in Icheon, Chuncheon, Jecheon and Naju areas. The observations were made in the nuseries and in the fields. In the nurseries, only cultivars Daesanbyeo and Hyangmibyeo 2 showed moderate levels of resistance to leaf blast, with the disease index 0 to 6. From the field observations, it was found that cultivars Hyangmibyeo 2 and Suwon 414 were highly resistant to leaf blast, but susceptible to neck blast. the fields, leaf blast was not observed. In general, there was great yearly and regional variation in the incidence of neck blast within the same cultivars, some times ranging from 0 to 100% of incidence. However, the range of fluctuation in the disease incidence were relatively small in the cultivars Daejinbyeo (0∼17.5%), Daesanbyeo (0∼4.0%), Donganbyeo (0∼21.4%) and Hwasambyeo (0∼13.9%). Hyangmibyeo 2 and Seojinbyeo were rarely infected with neck blast in Chuncheon and Naju all of the years, the same cultivars were severely infested with neck blast; 45.1 and 45.5%, respectively, in Jecheon in 1995. The occurrence of different races of rice blast fungus were different at different areas. However, it was found that in Icheon, Chuncheon, Jecheon and Naju areas, the dominant races were KI-409, KJ-201 and KJ-301.

• 한국작물학회지
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• 제48권4호
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• pp.316-321
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• 2003

Analysis of breeding gains in grain yield has been intensively conducted in wheat, barley, oat, maize, and soybean. Such information is limited in rice. The objective of this study was to compare the breeding gains and cultural gains contributed to yield gains of Korean rice varieties since early 1900s. Two sets of yield data were used for analysis; the historical yield data of 1908 for old japonica cultivars, and present yield data in the years from 1996 to 1998 for the six cultivars, consisting of previous two old cultivars and four contemporary cultivars. The old cultivars were two native cultivars, Jodongi and Damageum, while contemporary cultivars were two premium quality japonica cultivars, Hwaseongbyeo and Dongjinbyeo, and two Tongil-type cultivars, high yielding cultivars developed from indica/japonica hybridization, Milyang23 and Dasanbyeo. The yield differences of old cultivars between the experiments in 1908 and the experiments from 1996 to 1998 were estimated as cultural gains (1.84 tons $\textrm{ha}^{-1}$) due to the improvement of cultivation technology. Yield differences between the old cultivars and contemporary cultivars were considered total yield gains during the periods. These were 2.51 tons $\textrm{ha}^{-1}$ for japonica cultivars and 3.81 tons $\textrm{ha}^{-1}$ for Tongil-type cultivars. From these data, the genetic gain of 0.67 tons $\textrm{ha}^{-1}$ and 1.97 tons $\textrm{ha}^{-1}$ were estimated for japonica cultivars and Tongil-type cultivars respectively. The ratio between cultural gain and genetic gain appeared to be 2.7:1 for japonica cultivars and 1:1 for Tongil-type cultivars. This analysis clearly showed the higher genetic contribution in Tongil-type cultivars than in japonica cultivars, suggesting a guideline to be used when planning new yield improvement programs. Additional implication has emerged when a better yield response to modem cultivation technology was found in one of the old cultivars, suggesting the combined improvement between breeding and cultural improvement is necessary for attaining the maximum yield capacity of a crop.

• 한국작물학회지
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• 제53권spc호
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• pp.53-57
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• 2008

2006년도 고품질 쌀로 선정된 고품벼, 운광벼, 삼광벼를 기존의 일품벼와 대비하여 의성과 경주의 탑라이스 재배지역에서 2년간 적응시험을 하여 각 품종들의 품질과 미질 특성을 조사한 결과는 다음과 같다. 1. 10a당 수량은 의성, 경주 모두 일품벼가 586 kg, 560 kg으로 가장 많은 수량을 보였으나, 완전미 수량은 삼광벼가 의성과 경주에서 각각 519 kg, 495 kg으로 일품벼보다 더 높은 수량을 보였다. 2. 쌀의 외형상 품위에서 완전립 비율은 삼광벼, 고품벼가 90.7%, 82.5%로 일품벼의 77.5%보다 높았다. 3. 단백질 함량은 삼광벼가 6.2%로 가장 낮았으며, 식미치에서는 삼광벼가 85.9%로 가장 높았다. 4. 쌀가루의 점도 특성에서 최고 점도는 의성의 운광벼가 3180으로 가장 높았으며, 경주의 일품벼가 2255로 가장 낮았다. 5. 밥의 물리적 특성에서 경도는 삼광벼가 평균 3174로 가장 낮았으나, 부착성이 -132로 높게 나왔다.

• 농업과학연구
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• 제45권3호
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• pp.355-363
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• 2018

This study was conducted to investigate suitable rice cultivars for various rice based cropping systems in a paddy field in the Yeongnam plain area. Thirteen rice cultivars (5 early, 3 medium and 5 mid-late maturing cultivars) and three transplanting dates (June 5, June 25 and July 5) were evaluated in this study. The mid-late and early maturing cultivars for the July 5 and June 25 transplanting headed before August 30 which is the safe heading date in the Yeongnam plain area, ranging from Aug. 26 - 28 and Aug. 18 - 23, respectively. The safe harvest time of rice for double and triple cropping systems should be before the middle of October for the cultivation of the succeeding winter crops. The rice yield was the highest for the June 5 transplanting regardless of the rice cultivars, and it gradually decreased as the transplanting date was delayed from June 5 to July 5 due to a decrease in the spikelet numbers per panicle number and in the ripened grain rate. In contrast, the other yield parameters that include the panicle number per $m^2$, the 1,000-brown rice weight, and the ripened grain ratio were not significantly affected. The result indicates that based on the milled rice, heading time and harvest time, a medium maturing cultivar (Haiami and Samdeog) would be applicable to a winter barley/wheat, garlic/onion-summer rice double cropping, while a mid-late cultivar (Saeilmi, Saenuri and Hyunpoom) would be suitable for a spring potato/waxy corn-summer rice double cropping in the Yeongnam plain area. On the other hand, an early maturing cultivar (Unkwang, Jokwang and Haedamssal) would be preferable for a triple cropping because of the short growth period of rice.

• 한국환경농학회지
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• 제29권1호
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• pp.1-6
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• 2010

Organic farming system in rice paddy is rapidly expanding in Korea. This study was to find out optimum japonica rice cultivars for organic farming. A field research was conducted to evaluate the characteristics of japonica rice cultivars under no-tillage paddy at Doo-ryangmyeon, Sacheon, Gyeongsangnam-do, Korea. The experimental soil was Juggog series (silty clay loam: 56.0% silt, 31.2% clay and 12.8% sand). In experiment, ten lines of Japanese rice cultivars were tested under no-tillage amended with rye (NTR) and no-tillage without cover crop treatment (NTNT). In addition, two Korean japonica rice cultivars as check cultivars were used in this study. The grain yield in NTR was significantly higher in 6.13 Mg $ha^{-1}$ for Kinuhikari, 5.30 Mg $ha^{-1}$ for Komekogane, 5.25 Mg $ha^{-1}$ for Kosihikari, 5.22 Mg $ha^{-1}$ for Mazizbare and 5.12 Mg $ha^{-1}$ for Akitakomachi compared to two Korean rice cultivars (4.57 Mg $ha^{-1}$ for Hwayoungbyeo and 4.00 Mg $ha^{-1}$ for Ilmibyeo) in that order. While, grain yield in NTNT was significantly higher in 4.90 Mg $ha^{-1}$ for Akitakomachi 3.81 Mg $ha^{-1}$ for Hinohikari, 3.74 Mg $ha^{-1}$ for Umezkusi, 3.67 Mg $ha^{-1}$ for Kosihikari and 3.54 Mg $ha^{-1}$ for Dondokuri compared to 3.02 Mg $ha^{-1}$ for Ilmibyeo and 2.36 Mg $ha^{-1}$ for Hwayoungbyeo, respectively. The number of panicle per $m^2$ and grain number per panicle were indispensible for increasing the yield of rice. These results were able to find out optimum japonica rice cultivar Akitakomachi for organic farming in no-tillage paddy.

• 한국자원식물학회지
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• 제12권3호
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• pp.192-197
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• 1999

유색미인 흑진주벼 등 5종, 일반미인 동진벼, 향미인 향남벼을 대상으로 이들 품종의 현미 중에 함유된 지방질의 함량과 지방질의 조성을 비교 연구하였다. 1. 총지방질 함량은 건물기준으로 2.04 - 4.68%로 Tohoku 149호, 한산흑미, 상해향혈라 순으로 많았고 흑남벼, 향남벼와 동진벼에서는 비교적 적었으며 그들간에는 차이가 없었다. 2. 총지방질의 조성은 sterol ester & hydrocarbon, triglyceride, free fatty acid, diglyceride, free sterol 등 5종이 동정되었다. 그중 triglyceride의 비율이 가장 높았고 그 다음으로 diglyceride 와 free sterol의 비율이 높았다. 일반미와 유색미 및 향미간에 비교했을때 triglyceride의 비율은 향미와 유색미가 일반미보다 낮은 반면 diglyceride의 비율은 향미와 유색미에서 일반미인 동진벼에 비해 월등히 높았다. 3. 총지방질 중 지방산 조성은 모든 품종 다같이 linoleic acid, oleic acid 및 palmitic acid가 주된 지방산이었고 linolenic, stearic acid은 소량이 함유되어 있었으며, erucic acid는 일반미인 동진벼에는 함유되어 있지 않았다. 양적으로 많은 지방산을 품종별로 비교해 보면 oleic acid는 한산흑미가 41%로 가장 많았고, 그외 품종은 32-37% 범위이었다. 또한 linoleic adid 향남벼와 상해향혈라는 각각 37%그외 품종은 32 - 36%의 범위이었다.

• 한국식물병리학회지
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• 제2권2호
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• pp.69-81
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• 1986

성체식물기에 잎도열병에 대해 저항성인 벼 품종 선발을 위해 한국에서 재배되거나 육종재배로 쓰이고 있는 32개의 벼 품종을 도열병검정 못자리에 공시하였다. 생육시기가 다른 각 잎에 자연감염된 발병율을 토대로 비교할 때, 16개의 통일형 품종들은 모두 고도 저항성이었으나 16개의 일본형 품종들은 잎도열병에 대해 다양한 저항성정도를 나타내었다. 잎도열병에 대한 저항성정도는 품종에 따라 다르지만, 식물체가 성숙해 갈수록 양적저항성정도는 모든 품종에서 증가하였다. 감수성에서 저항성으로 바귀는 엽위는 품종에 따라 달랐다. 도열병균에 대한 품종의 감수성반응이 상위엽에서 저항성반응으로 뚜렷하게 바뀌었다. 잎도열병에 대한 양적 저항성정도가 큰 품종일수록 하위엽에서 저항성반응을 나타내었다. 생육후기에 도열병감염을 급격히 감소시키는 품종인 아까바레, 팔금, 진흥, 올찰, 도봉 및 은하는 포장에서 잎도열병에 대해 성체식물저항성을 보였다. 성체식물저항성품종들은 식물체가 성숙해감에 따라 최적, 질적으로 잎도열병에 대해 저항성을 나타내었다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.304-304
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• 2017

In semi-arid countries such as Namibia, the flooding unexpectedly happens in a rainy season, causing losses in the yield of upland-adapted cereal crop. In flooding conditions, rice roots sequentially form aerenchyma and a barrier to radial oxygen loss (ROL), and oxygen is released into the rhizosphere near the root tips. Iijima et al. (2016) and Awala et al. (2016) reported that close mixed-planting with rice can mitigate the flood stress of co-growing upland-adapted cereal crop by modifying their rhizosphere microenvironments via the oxygen released from the rice roots. Moreover, by using the model system of hydroponic culture, it was confirmed that oxygen from rice roots was transferred to co-growing upland-adapted cereal crop in close mixed planting system (Kawato et al., 2016). However, it is not sure whether the ability of oxygen release varies among rice cultivars, because Kawato et al. (2016) used only one japonica cultivar, Nipponbare (Oryza sativa). The objective of this study was to compare the ability of oxygen release in rhizosphere among rice cultivars. The experiment was conducted in a climate chamber in Kindai University. We used 10 rice cultivars from three different rice species (O. sativa (var. japonica (2), var. indica (3)), Oryza glaberrima Steud. (2) and their interspecific progenies (3)) to compare the ability of oxygen release from the roots. According to the method by Kawato et al. (2016), the dissolved oxygen concentration of phase I (with shoot) and phase II (without shoot) were measured by a fiber optic oxygen-sensing probe. The oxygen released from rice roots was calculated from the difference of the measurements between phase I and phase II. The result in this study indicated that all of the rice cultivars released oxygen from their roots, and the amount of released oxygen was significantly correlated with the above-ground biomass (r = 0.710). The ability of oxygen release (the amount of the oxygen release per fresh root weight) of indica cultivars (O. sativa) tended to be higher as compared with the other cultivars. On the other hand, that of African rice (O. glaberrima) and the interspecific progenies tended to be lower. These results suggested that the ability of oxygen release widely varies among rice cultivars, and some of indica cultivars (O. sativa) may be suitable for close mixed-planting to mitigate flood stress of upland-adapted cereal crop.

• 한국응용곤충학회지
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• 제31권3호
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• pp.256-275
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• 1992

Insects are among the most important abiotic and biotic constraints to rice production. National rice research programs are in various stages in the development and implementation of integrated pest management (IPM) stratagies for rice insect control. Among the various control tactics, insect resistant cultivars are sought as the major tactic in rice IPM. Through the activities of interdisciplinary teams of scientists significant progress has been made in the development and release of insect resistant cultivars to farmers. Because of its compatibility with other control tactics insect resistance has proven to fit well into the IPM approach to rice insect control agents and minimize the need for insecticide applications. The development of biotypes which overcome the resistance in rice plants has been a significant constraint in the breeding of rice for resistance to insects. Most notable examples in Asia are the green leafhopper, Nephotettix virescens, brown planthopper, Nilaparvata lygens and the Asian rice gall midge, Orseolia oryzae. The current breeding stratege is to develop rice cultivars with durable resistance on which virulent biotypes cannot adapt. In spite of the significant progress made in the breeding of insect resistant cultivars there are still numerous important rice insect species for which host plant resistance as a control tactic has not been fully utilized. Advances in biotechnology provide promise of solving some of the problems that have limited the use of host plant resistance as a major tactic in the integrated management of rice insect pests.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.27-27
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• 2017

The rapid growth of world population, reduction of cultivated areas for crop production, and detrimental effects of pests, diseases, and climate changes have required to breed new rice cultivars with high yield, accepted quality, but strong resistance to abiotic and biotic stresses. However, traditional breeding needs much time to breed a new cultivar, whereas the successful use of molecular breeding is still questionable. We have developed a novel mutation which allow to cross many rice cultivars together with low segregation, that allow to breed a new cultivar in only several cropping. The mechanism has been unknown, but we suggest that gene linkage may play a crucial role, of which the semi dwarf gene might be the center gene for gene linkage occurrence. The phenomenon of this possible gene linkage is contrary to Mendel rules, but it is promising to breed new rice cultivars, of which, the most elite genes in rice might be able to gather in a targeted rice variety.