중국 동북부지역 랴오닝성의 단둥(40°07'N 124°23'E)과 지린성의 궁주링(43°30'N 124°49') 및 룽징(42°46'N 129°26'E)에서 2020년과 2021년 벼 재배기간 중에 성페로몬트랩으로 이화명나방(Chilo suppressalis)(나비목: 포충나방과)의 성충 발생 시기를 조사하였다. 1화기 성충은 5월 중순부터 7월 하순 사이, 2화기 성충은 7월 중순부터 9월 중순 사이에 발생하여 세 지역 모두 연중 2회 성충 발생양상이 뚜렷하게 확인되었 다. 위도가 높은 지역에서 발생시기가 더 늦었다. 각 지역에서 관찰된 1화기 발생 시기를 기준으로 발생 시기 모델링을 통해 2화기 발생 시기를 추 정하고 관찰된 시기와 비교하였다. 네 개의 선행연구 자료로부터 성충, 알, 유충, 용 발육단계의 온도의존 생명현상(발육속도, 발육완성분포, 생존 율, 성충 노화율, 총산란수, 산란완성분포, 성충 생존완성분포) 모델들을 수집하거나 작성하였고, 이들을 선행 연구에 따라 단독으로 사용하거나 혼합하여 곤충 발생 시기 추정 소프트웨어인 PopModel에서 결합하였다. 모델링 결과에서 유충 발육기간이 짧게 관찰된 선행연구 자료를 기반으 로 하여 구성된 모형들이 2화기 성충 발생 시기를 더 근접하게 추정하였다. 2021년에는 단둥과 룽징에서 성충 조사 시기에 맞추어 이화명나방에 의 한 벼 피해주율의 변화를 조사하였다. 피해주율은 벼 재배기간 중 누적되어 2번의 증가시기가 뚜렷하게 나타났고, 이화명나방의 각 세대 유충에 의 해 발생한 것으로 추정되었다.

중부 평야지에서 중생종 벼 하이아미의 이앙시기에 따른 출수기의 변동과 출수 전후의 기상 및 수량 특성을 파악하고 적절한 재배시기를 제안하기 위하여, 이앙시기를 5월 10일부터 6월 24일까지 조절하여 3년간 국립식량과학원 중부작물부 수원 벼 재배시험 포장에서 시험한 결과는 다음과 같다. 1. 이앙기가 늦을수록 출수기까지는 일 평균기온이 높았으나 출수소요일수가 단축됨에 따라 적산온도가 적어졌고, 출수 후 40일간은 평균기온이 낮고 일조시간이 많은 경향이었다. 2. 이앙기~출수기와 출수 후 40일간의 평균기온은 시험연차보다 이앙시기에 따른 변이가 컸으나 일 평균 일조시간은 이앙시기 보다 시험연차에 따른 변이 정도가 더 커서, 이앙시기 조절에 의한 기상요인의 변화는 평균기온에서 뚜렷하게 나타났다. 3. 이앙시기가 늦어짐에 따라 수수는 감소하였으나 수당영화수가 증가하였고, 결과적으로 이앙시기 지연에 의한 출수소요일수의 단축이 sink size의 감소로 이어지지는 않았다. 4. 이앙시기 조절에 의한 m2당 영화수의 변화는 등숙비율과 뚜렷한 상관을 보이지 않았으나, 출수 후 40일간 평균기온이 낮아짐에 따라 현미천립중은 유의하게 증가하는 추세를 보였다. 5. 쌀수량은 이앙시기에 따라 유의차를 보이지 않았던 반면, 완전립 비율은 6월 24일까지 이앙이 늦어짐에 따라 높아지는 추세를 보였으며 그에 따라 완전미 수량도 비슷한 경향을 보였다. 6. 결과적으로, 중부 평야지에서 하이아미는 이앙시기를 6월 중~하순으로 늦춤으로써 쌀 품위를 높이고 완전미 수량을 향상시킬 수 있는 것으로 분석되었는데, 등숙 후기의 저온 피해 우려를 고려하면 6월 중순에 이앙하는 것이 안전할 것으로 판단된다.

This study was conducted, using 10 high-quality rice varieties, at 24 experimental sites in 2013 and 2014 to analyze the comparative relationship among head rice yield (HRY), its attributes and sub-attributes. In the data set pooled across sites, years and varieties, where regional and varietal variations were combined, HRY was associated with milled rice yield (MRY) more closely than percentage of head rice (PHR) although both MRY and HRY demonstrated significant relationship with HRY. In the PHR higher than 80%, compared to 80% or less, fitness of the regression between PHR and HRY decreased. MRY and PHR, the two attributes of HRY, were not significantly associated with each other. Regional variation of HRY was associated only with MRY while varietal variation of HRY was related to both MRY and PHR. HRY and MRY showed regional variation greater than varietal variation meanwhile PHR demonstrated regional and varietal variations in a similar range. In the data set pooled across sites, years and varieties, MRY demonstrated relationship with spikelets per square meter (SPIK) in a higher significance than percentage of grain filling (PGF) and 1000-brown rice weight (TBRW). Both regional and varietal variations of MRY showed significant relationship only with SPIK, neitherwith PGF nor TBRW. It is concluded that regional variation of HRY was affected by MRY, varietal variation by both MRY and PHR, and region-variety combined variation mainly by MRY.

총체 사료용 벼의 초기 신장성과 입모 특성을 알아보기 위하여 수원 소재 국립식량과학원 시험포장 조건에서 파종시기를 조절하고, 인공기상연구동 정밀유리실에서 입모기간 중 평균기온을 조절하여 검토한 결과는 다음과 같다. 1. 포장조건에서 총체 사료용 벼 품종 및 계통의 m2당 입모수는 파종시기별로 4월 30일 파종에서 낮은 경향을 보였으나 5월 10일~ 6월 9일 파종에서는 비슷하였고, 품종별로는 녹양에 비해 목우와 수원560에서 많은 경향이었다. 평균기온 18 ~ 24oC 범위의 실내시험에서는 총체 사료용 벼의 입모율은 처리온도간 차이가 없었으며, 모든 온도 처리에서 일반형 품종인 일품보다 낮은 경향을 보였다. 2. 파종 후 30일의 초장은 포장시험에서 파종시기가 늦을수록, 실내시험에서 처리온도가 높을수록 길어졌다. 목우와 수원 560은 녹양보다 입모기간 중 기온 상승에 따른 초장 신장 정도가 컸으며, 특히 목우는 초장 신장 효과가 다른 품종에 비해 고온인 24oC에서 높았다. 3. 파종 후 30일의 건물중은 입모기간 중 평균기온 24oC까지는 기온이 높아질수록 모든 품종에서 증가하였다. 반면 기온이 24oC에서 27oC로 상승했을 때의 건물중은 녹양에서는 비슷하였고 목우와 수원560에서는 감소하였는데 특히, 수원 560의 감소 정도가 컸다. 4. 모든 품종에서 묘 충실도는 입모기간 중 평균기온 24oC까지는 온도가 높을수록 증가하였다. 반면 24oC에서 27oC로 상승한 경우 묘 충실도가 모든 품종에서 감소하였는데, 특히 수원560에서 감소 정도가 컸다. 5. 결과적으로, 담수표면산파에서 초기 신장 촉진과 건전한 입모에 가장 효과적인 입모기간 중의 평균기온은 녹양에서 21oC, 목우와 수원560에서 24oC였으며, 수원560의 경우 24oC 이상의 고온에서는 묘가 연약해졌다.

최근 농가에서 모떼기 작업의 용이성 때문에 널리 이용되는 개량상자를 위한 적정 물관리 방법을 본 연구에서 제시하였다. 개량상자 +중량상토 조합으로 마른 못자리와 물 못자리에서 고랑관개와 상면관개를 하여 시험하였는데 그 결과 못자리 종류에 관계없이 상면관개가 안정적인 물관리 방법으로 선정되 었으며 고랑관개는 안정성이 낮아 배제되었다. 선정된 물관리방법이 경량 상토 및 매트상토에서도 유효한지 확인하기 위해 상면관개를 하여 못자리 별로 중량상토, 경량상토, 매트상토에서의 물관리 시험을 시행하였다. 그 결과 상면관개는 동일 못자리내에서 상토 종류에 관개없이 정상적으로 이앙 가능한 수 준의 모를 얻을 수 있었다. 따라서 개량상자를 이용할 경우 못자리 종류와 상토에 관계없이 상면관개를 해야만 하며 모를 안정적으로 얻기 위해서는 물 수위가 낮아지지 않게 주의해야 한다.

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°C and sunshine for 5.8 hours being recorded at the transplanting on May 5, and with a temperature of 21.0°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°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°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°C during active filling stage.

This study was carried out in 2014 and 2015 to investigate the effect of transplanting density on panicle production and to analyze the relationship of panicle production with yield traits in the mid-maturing quality rice cultivar ‘Haiami’ in the mid-plain area of Korea. Number of tillers per square meter increased by reducing planting distance and increasing seedling number per hill. These effects were maintained until maturity and were reflected in the final number of panicles per square meter, although the effect of planting density decreased as rice growth progressed. However, increased panicle number per square meter following dense planting did not improve head rice yield. Panicle number per square meter was negatively associated with spikelet number per panicle and was not correlated with other yield components or head rice yield. Head rice yield was not correlated with head rice percentage but was closely and positively correlated with milled rice yield. Milled rice yield did not increase with grain filling percentage but increased with spikelet number per square meter. Spikelet number per square meter increased with both spikelet number per panicle and panicle number per square meter, although the former had a greater influence. Therefore, we conclude that head rice yield of the ‘Haiami’ cultivar grown in the mid-plain area of Korea is not improved with an increased panicle number following high planting density but it could be improved with high milled rice yield by increasing spikelet number per unit area.

The increase in carbon stock and sustainability of crop production are the main challenges in agricultural fields relevant to climate change. Methane is the most important greenhouse gas emitted from paddy fields. This study was conducted to investigate the effects of tillage and cultivation methods on methane emissions in rice production in 2014 and 2015. Different combinations of tillage and cultivation were implemented, including conventional tillage-transplanting (T-T), tillage-wet hill seeding (T-W), minimum tillage-dry seeding (MT-D), and no-tillage-dry seeding (NT-D). The amount of methane emitted was the highest in T-T treatment. In MT-D and NT-D treatments, methane emissions were significantly decreased by 77%, compared with that in T-T treatment. Conversely, the soil total carbon (STC) content was higher in MT-D and NT-D plots than in tillage plots. In both years, methane emissions were highly correlated with the dry weight of rice (R 2 = 0.62~0.96), although the cumulative emissions during the rice growing period was higher in 2014 than in 2015. T-T treatment showed the highest R 2 (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that NT-D practice in rice production could reduce the methane emissions and increase the STC content without loss in grain yield.

A long-term field experiment under different fertilization treatments had been conducted to explore the effects of rice yield and soil chemical properties from 1978 to 2008 in Suwon, Korea. The paddy was applied eight fertilization treatments which were F0 (no fertilizer), PK (phosphorous and potassium), NK (nitrogen and potassium), NP (nitrogen and phosphorous), NPK (nitrogen, phosphorus and potassium), NPKC (NPK with compost), NPKS (NPK with straw) and NPKL (NPK with lime). Results of 31 years experiment showed that yield index (the ratio of yield in each treatment to NPK) was the lowest in F0 (0.52) and the highest in NPKC (1.18). Yield index was gradually increased in NPKC but decreased in F0 and NK. The yield index of PK, NP, NPKS and NPKL were not changed long-term treatment. Soil acidity of NPKL showed the highest with pH 7.9, and that of other treatments ranged from pH 6.3 to 6.8. Available phosphorous content of soil was increased in all plots by long-term fertilization, was the highest in PK and NPKC. Soil organic matter was higher in NPKC (1.8%) and NPKS (1.8%) than other treatments (1.3~1.4%) in the early experiment, but that was remarkably increased in only NPKC (2.5%) according to annual long-term application. Thus we suggest that annual compost application with optimum NPK could make stable and sustainable rice production.

Relationship between grain quality-related traits and daily mean temperature/sunshine hours during grain filling stage was analyzed using eleven high quality rice varieties at 24 experimental sites through eight provinces of Korea in 2013~2014. In the data set pooled across varieties, experimental sites and years, grain quality-related traits such as percentage of head rice (PHR), head rice yield (HRY), protein in milled rice (PRO) and Toyo Mido Meter glossiness value (TGV) were higher at the temperature lower than 22.6℃ for 40 days after flowering (DAF), which was optimum for percentage of grain filling in this study. Optimum sunshine hours for 40 DAF were 6.0~6.1 hr d -1 when considered PHR, HRY and TGV. PRO was associated with daily mean temperature and sunshine hours for 40 DAF in more varieties than the other traits. PRO was closely correlated with daily mean temperature during early filling stage and sunshine hours during early to mid filling stage, compared to other stages during grain filling. It is concluded that general trend in the variation of grain quality-related traits could be explained by the changes in daily mean temperature and sunshine hours during grain filling. In addition, climate conditions during early grain filling stage played important roles to enhance grain quality.

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature (27℃±4℃) treated both rice cultivars were decreased than those of control temperature (22℃±4℃) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

1. 생산지에 따라 벼 종자의 수발아립률 차이가 컸던 호 품벼의 출아율과 발아율을 조사한 결과, 수발아율 8% 인 시료는 수발아율이 1%인 시료에 비해 발아율과 출 아율, 종자활력이 30% 낮았다. 2. 수발아율이 높은 시료는 수발아립의 변색 정도가 심 하고 미발아율과 부패율이 높았다. 수발아립은 배가 돌출하고, 변색된 배유와 곰팡이 감염이 관찰되었으며 배유의 1/2이상이 변색된 종자는 발아율이 매우 낮았다. 3. 종자의 발아 진행정도에 따라 현미의 변색이 심해졌 는데, 싹이 3 mm이상일 경우 배유의 1/2정도가 변색 되었다. 4. 발아 종자는 싹이 3 mm이상일 때부터 재발아율이 크 게 떨어졌으며 퇴화촉진처리 후 발아율의 감소가 더 컸다. 특히 퇴화촉진처리한 발아 종자는 싹이 2 mm부 터 종자활력이 크게 감소하였다. 결론적으로 수발아 발생이 심할수록 파종기 발아율과 출 아율의 감소가 크고, 수발아가 3 mm이상 발생하면 발아율 이 크게 저하될 것으로 생각된다. 또한 수발아는 동일 품종 과 동일 지역에서도 포장 간 차이가 크게 발생할 수 있으므 로 재배관리에 주의해야 한다.

The amount of salt to make seed sorting solution of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18 L water, which is lower amount than currently used. Five rice cultivars were examined. Percent germination and seedling emergence were not similar. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. However, if seeds with low speicific gravity are produced due to the bad grain filling condition and consequently total seed content of low specific gravity increases, results will be differnt. Reduction in total growth and yield could occur. It will be important to comply with the seed sorting criterion of 1.13 for Japonica, 1.06 for Tongil, and 1.04 for waxy rice variety to ensure the maximum rice growth and yield.

The amount of salt to make seed sorting solution for rice of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18L water, which is lower amount than currently used. Various rice (Oryza sativa L.) cultivars were used to examine seed specific gravity effect on germination, seedling emergence, and early growth. Percent germination and seedling emergence were not different. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. As a result, it is considered that selecting seeds with water (larger than specific gravity of 1.00) instead of salt solution will not make large reduction in seedling emergence rate and have no effects in early growth.

Experiments were conducted with aims to (1) estimate the biomass yield potential, (2) characterize the biomass and digestible dry matter production, and (3) reveal the characteristic seedling establishment of a whole crop rice variety, Nogyangbyeo, in dry- and wet-seeded rice. Maximum aboveground total biomass of Nogyangbyeo was 18 t ha-1 in dry-seeded rice and 20 t ha-1 in wet-seeded rice. Biomass yield potential of Nogyangbyeo was lower than that of Dasanbyeo. Comparatively, Nogyangbyeo was straw-dependent and Dasanbyeo was grain-dependent for biomass accumulation. Percentage of digestible dry matter (DDM) was higher in panicles than straw. Digestible dry matter yield was determined mainly by biomass yield rather than DDM percentage. Number of seedling establishment in Nogyangbyeo was 73m-2 in dry-seeded rice and 109m-2 in wet-seeded rice. Poor seedling establishment of dry-seeded Nogyangbyeo in the field condition was the result of low seed germination under low temperature and poor seedling emergence by deep sowing. Low seedling emergence rate of Nogyangbyeo was attributed mainly to slow elongation growth by slow leaf development and partly to mesocotyl and 1st internode lengths, not to genetically defined leaf length. The slow elongation growth of Nogyangbyeo was the same even in the high daily mean temperature of 24~circC . Results suggest DDM yield in rice can be improved simply by increasing biomass and whole crop rice varieties should be adaptable to direct-seeding.

Grain filling is a crucial factor that determines grain yield in crops since it is the final process directly associated with crops' yield performance. Grain filling process can be characterized by the interaction of rate and duration of grain filling. This study was conducted, using 16 temperate japonica rice genotypes, with aims to (1) seek variations in grain filling duration and rate on area basis, (2) compare the contribution of grain filling duration and rate to grain yield, and (3) examine the influence of temperature and solar radiation for effective grain filling on grain yield in relation to grain filling duration and rate. Grain filling rate and duration exhibited highly significant variations in the ranges of 20.7~46.3~;g~;m-2d-1~;and~;11.2~35.5 days, respectively, depending on rice genotypes. Grain yield on unit area basis was associated positively with grain filling duration but negatively with grain filling rate. Grain filling rate and duration were negatively correlated with each other. Final grain weight increased linearly with the rise in both cumulative mean temperature and cumulative solar radiation for effective grain filling. Higher cumulative mean temperature and cumulative solar radiation for effective grain filling were the results of longer grain filling duration, but not necessarily higher daily mean temperature and daily solar radiation for effective grain filling. Grain filling rate demonstrated an increasing tendency with the rise in daily mean temperature for effective grain filling but their relationship was not obviously clear. It was concluded that grain filling duration, which influenced cumulative mean temperature and cumulative solar radiation for effective grain filling, was the main factor that determined grain yield on unit area basis in temperate Japonica rice.

Germination and early elongation of rice after germination were investigated in anoxic air treatment, nitric oxide gas treatment, and six concentrations of mercuric chloride solutions to determine the effects of limited oxygen environment, nitric oxide, and inhibited water flux through cell membrane in 17~circC . Anoxic air treatment affected germination of tested six varieties very little. However root elongation rates were severely inhibited while shoot growth was affected less. Reductions in shoot and root elongations demonstrated genotypic variations. Nitric oxide delayed the germination of rice even though it didn't affect the final percent germination. Elongations of root and shoot were inhibited in nitric oxide treatment. The inhibitor effect of nitric oxide on the shoot elongation of rice was less severe, while nitric oxide completely inhibited the root emergence of rice. Concentrations of HgCl2 greater than 300~muM dramatically reduced the rate and percentage of germination when compared to distilled water treatment. The reduced percent germination showed the greatest variation among rice varieties in 500~muM solution of mercuric chloride. Ansanbyeo, Jinheung, and Odaebyeo were affected less by HgCl2 , Nonganbyeo and Sangmibyeo were intermediate, and the germination of Andabyeo was greatly reduced by HgCl2 . Root elongation of germinated rice seedlings was more sensitive to oxygen deficits, nitric oxide, and HgCl2 treatments than germination and shoot elongation. In conclusion, poor seedling establishment of rice sown in flooded paddy soils, in which the oxygen supply to the seeds is restricted, appears to the result of limited root elongation rate.