Maturing Rice Cultivar Research Articles

‘Baekokhyang’, a Late Maturing Rice Cultivar with Aroma Adaptable in the Chungnam Plain Area

‘Baekokhyang’, a Late Maturing Rice Cultivar with Aroma Adaptable in the Chungnam Plain Area

High Grain Quality Mid-Late Maturing Rice Cultivar ‘Namchan’ with High Yield Performance under Low-Nitrogen Fertilizer Conditions

High Grain Quality Mid-Late Maturing Rice Cultivar ‘Namchan’ with High Yield Performance under Low-Nitrogen Fertilizer Conditions

“Yeoreumi,” an Early Maturing Rice Cultivar Adaptable for Early-Transplanting Cultivation in the Chungnam Plain Area

“Yeoreumi,” an Early Maturing Rice Cultivar Adaptable for Early-Transplanting Cultivation in the Chungnam Plain Area

Changes in Growth and Quality Traits According to Transplanting Dates using ‘Bbareumi’, an Extremely Early Maturing Rice Cultivar, in the Chungnam Plain Area

Changes in Growth and Quality Traits According to Transplanting Dates using ‘Bbareumi’, an Extremely Early Maturing Rice Cultivar, in the Chungnam Plain Area

Exploration of the genomic atlas of Dof transcription factor family across genus Oryza provides novel insights on rice breeding in changing climate.

DNA-binding with one finger (Dof) transcription factors have been demonstrated to regulate various stresses and developmental processes in plants. Their identification and comparative evolutionary analyses in cultivated and wild species of genus oryza were yet to be explored. In this context, we report a comprehensive genomics atlas of DNA-binding with one finger (Dof) family genes in 13 diverse rice genomes (five cultivated and eight rice wild-relatives) through a genome-wide scanning approach. A galore of 238 Dof genes, identified across the genus Oryza, are categorized into seven distinct subgroups by comparative phylogenetic analysis with the model plant Arabidopsis. Conserved motifs and gene structure analyses unveiled the prevalence of species- and subgroups-specific structural and functional diversity that is expediating with the evolutionary period. Our results indicate that Dof genes might have undergone strong purifying selections and segmental duplications to expand their gene family members in corresponding Oryza genomes. We speculate that miR2927 potentially targets the Dof domain to regulate gene expression under different climatic conditions, which are supported by in-silico and wet-lab experiments-based expression profiles. In a nutshell, we report several superior haplotypes significantly associated with early flowering in a treasure trove of 3,010 sequenced rice accessions and have validated these haplotypes with two years of field evaluation-based flowering data of a representative subpanel. Finally, we have provided some insights on the resolution of Oryza species phylogeny discordance and divergence highlighting the mosaic evolutionary history of the genus Oryza. Overall, this study reports a complete genomic landscape of the Dof family in cultivated and wild Oryza species that could greatly facilitate in fast-track development of early maturing and climate-resilient rice cultivars through modern haplotype-led breeding.

Influence of Cultivation Methods and Transplanting Periods on Heading Stage and Occurrence of Hull-Cracked Rice Grains among the Early Maturing Rice Cultivars in Akita Prefecture

Influence of Cultivation Methods and Transplanting Periods on Heading Stage and Occurrence of Hull-Cracked Rice Grains among the Early Maturing Rice Cultivars in Akita Prefecture

‘Jungdream’—An Early Maturing and Good Eating-Quality Rice Cultivar Suitable for Growing in the Gyeonggido Province, South Korea

Jung-Hee Jang, Byoung-Rourl Choi, Tae-Jin Won, Ji-Hye Lee, Jong-Hyeong Lee, Sang-Wook Han, Jae-Eun Jang, Jae-Soon Seo, Jung-Hyeun Ji, In-Tae Park, Hae-Chun Choi, and Gwang-Ho Kim. Korean J. Breed. Sci. 2021;53:170-6. https://doi.org/10.9787/KJBS.2021.53.2.170

An Evaluation of Temperature-Based Agricultural Indices Over Korea From the High-Resolution WRF Simulation

This study evaluates the performance of dynamical downscaling of global prediction generated from the NOAA Climate Forecast System (CFSv2) at subseasonal time-scale against densein-situobservational data in Korea. The Weather Research and Forecasting (WRF) double-nested modeling system customized over Korea is adopted to produce very high resolution simulation that presumably better resolves geographically diverse climate features. Two ensemble members of CFSv2 starting with different initial conditions are downscaled for the summer season (June-July-August) during past 10-year (2011–2020). The comparison of simulations from the nested domain (5 km resolution) of WRF and driving CFSv2 (0.5°) clearly demonstrates the manner in which dynamical downscaling can drastically improve daily mean temperature (Tmean) and daily maximum temperature (Tmax) in both quantitative and qualitative aspects. The downscaled temperature not only better resolves the regional variability strongly tied with topographical elevation, but also substantially lowers the systematic cold bias seen in CFSv2. The added value from the nested domain over CFSv2 is far more evident in Tmax than in Tmean, which indicates a skillful performance in capturing the extreme events. Accordingly, downscaled results show a reasonable performance in simulating the plant heat stress index that counts the number of days with Tmax above 30°C and extreme degree days that accumulate temperature exceeding 30°C using hourly temperature. The WRF simulations also show the potential to capture the variation of Tmean-based index that represents the accumulation of heat stress in reproductive growth for the mid-late maturing rice cultivars in Korea. As the likelihood of extreme hot temperatures is projected to increase in Korea, the modeling skill to predict the ago-meteorological indices measuring the effect of extreme heat on crop could have significant implications for agriculture management practice.

High Grain Quality Mid-late Maturing Rice Cultivar ‘Yechan’ with Lodging Tolerance and Multiple Disease Resistance

High Grain Quality Mid-late Maturing Rice Cultivar ‘Yechan’ with Lodging Tolerance and Multiple Disease Resistance

‘Chamdream’, A Medium-Late Maturing and Good Eating-Quality Rice Cultivar Highly Suitable for Growing in the Gyeonggido Province, South Korea

‘Chamdream’, A Medium-Late Maturing and Good Eating-Quality Rice Cultivar Highly Suitable for Growing in the Gyeonggido Province, South Korea

Bacterial Blight Resistance Genes Pyramided in Mid-Late Maturing Rice Cultivar ‘Sinjinbaek’ with High Grain Quality

Bacterial Blight Resistance Genes Pyramided in Mid-Late Maturing Rice Cultivar ‘Sinjinbaek’ with High Grain Quality

Multiple Disease Resistant Early Maturing Rice Cultivar 'Joil' with High Grain Quality Adaptable to Early Transplanting Cultivation in the Southern Plain Area

Multiple Disease Resistant Early Maturing Rice Cultivar 'Joil' with High Grain Quality Adaptable to Early Transplanting Cultivation in the Southern Plain Area

Genetic Basis of Combining Ability for Various Quantitative Traits Using CMS Lines of Rice (Oryza sativa L.)

Summary Line × Tester experiment was carried out at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha, Kafrelsheikh, Egypt during three growing seasons to evaluate the performance of 21 F1 hybrids along with their parents. Three cytoplasmic male sterile lines, two wild abortive (Wild Abortive); IR69625A, IR70368A and one (Kalinga) K17A as female were tested with seven cultivars/lines as testers. The analysis of variance detected that, highly significant variations among genotypes (parental lines with their crosses) for all traits in both seasons and in their combined analysis. Two hybrid combinations; IR69625A×Giza178 and IR69625A×Giza179 were recorded the best values for grain yield under both seasons and their combined. General combining ability (GCA) and specific combining ability (SCA) effects of genotypes for the studied traits were estimated. The results indicated that, K17A (female) and Giza 179 (male) were the best combiner for early heading date and could be useful to breed early maturing rice cultivars. The CMS line IR69625A and Giza178, Giza179 gave highly significant and positive GCA value and so appeared to be good parental lines combiner in hybrid combinations for high grain yield/plant. The positive values of GCA mean increased for grain yield/plant, which could be useful in breeding programs for high yield potential rice cultivars. The hybrid combination IR69625A×Giza179 showed highly significant and positive SCA estimates under both seasons and their combined. In conclusion, it is clear that this hybrid seemed promising hybrid for earliness and high grain yield under Egyptian conditions.

新潟県における水稲品種開発と晩生新品種「新之助」の育成

新潟県における水稲品種開発と晩生新品種「新之助」の育成

水稲早生品種の登熟期間の物質生産と品質食味要因の関係の解析 : I. 乾物生産と窒素吸収量の品種間差

水稲早生品種の登熟期間の物質生産と品質食味要因の関係の解析 : I. 乾物生産と窒素吸収量の品種間差

Temperature and drought impacts on rice production: An agronomic perspective regarding short- and long-term adaptation measures

This review addresses short- and long-term adaptation strategies in rain fed and irrigated rice production systems under two climate change scenarios, specifically temperature increases and drought incidence. Each scenario is discussed based on rice plant physiological responses to abiotic stress and, where applicable, consequent yield losses. Possible short- and long-term adaptation measures, mainly focused on crop management strategies and germplasm development, are suggested to overcome production losses. Increased temperature, for example, can adversely affect rice yields either as a result of spikelet sterility or reduced accumulation of assimilates. Most agronomic operations to minimize the impact of increased temperatures involve early sowing or the use of early maturing rice cultivars to avoid high temperatures at grain filling. These measures might be feasible, but inadequate, as periods of increased temperature become more frequent and severe particularly in regions where temperatures are already above optimum for rice growth. On the other hand, rice germplasm from exceedingly warm environments can be used for selecting traits which are appropriate for the development of high temperature stress-tolerant rice cultivars. Drought incidence causes stomata closure, which reduces the leaf CO2/O2 ratio, resulting in photosynthesis inhibition and subsequent reductions in biomass production and the life cycle of the plant. These are manifested in significant yield losses. Drought is a common phenomenon in many rice growing environments, and research on developing cultivars capable of escaping, avoiding and/or tolerating drought merits further attention. Crop management, including water management techniques, to mitigate drought stress has also advanced. The implementation of a water-saving technology called alternate-wetting and drying, for example, enables optimum use of irrigation water and reduces methane emissions by 48% compared to continuous flooding of rice fields. Therefore, the suggested adaptation measures are also aligned and discussed based on their potential to decrease methane emissions from rice fields. This paper highlights the importance of germplasm development and improved agronomic practices as the center piece of climate change adaptation in rice farming systems.

Comparison of Yield and Quality Characteristics on Mid-Late Maturing Rice Cultivars in Major Cultivation Areas of Gangwon Province

강원지역 주요 농업지대별 알맞은 최고품질의 중만생종 벼 품종을 선발하고자, 농촌진흥청에서 최근 육성한 중만생종 8개 품종을 대상으로 2013년부터 2014까지 2년간 춘천, 강릉, 철원 등 3개 지역에서 수행한 결과를 요약하면 다음과 같다. 1. 벼 생육기간 동안 평균기온은 2013년과 2014년 모두 춘천에서 평년대비 <TEX>$0.6{\sim}1.1^{\circ}C$</TEX>, 강릉 <TEX>$1.0{\sim}1.3^{\circ}C$</TEX>, 철원 <TEX>$0.1{\sim}0.7^{\circ}C$</TEX> 높았다. 등숙기 강수량은 2013년에 춘천에서 평년대비 52.5 mm 많았고 2014년에는 176.4 mm 적었으며, 강릉은 2013년에 103.1 mm 적었고 2014년에는 42.9 mm 많았다. 반면 철원은 2013년과 2014년 모두 225.9~322.7 mm 가량 적었다. 2. 등숙기 일조시간은 2013년에 춘천, 강릉 및 철원에서 각각 평년대비 142, 108 및 94시간 많았고, 2014년에는 춘천, 강릉에서 20~21시간, 철원에서는 82시간 많았다. 3. 2년간 평균 10a당 백미수량은 춘천에서 삼광벼와 대보벼 594 kg, 진수미벼 578 kg을 보였고, 강릉에서는 대보벼 555 kg, 호품벼 554 kg, 칠보벼 546 kg, 그리고 철원에서는 대보벼 504 kg, 하이아미벼 489 kg로 다른 품종들에 비하여 다소 높은 수량을 보였으나 품종간 유의적인 차이는 없었다. 4. 완전미율은 춘천에서 하이아미벼 95.6%, 진수미벼 94.7%, 미품벼 94.2%로 다른 품종에 비하여 뚜렷하게 높았고, 싸라기율과 심복백미율도 다소 낮았다. 강릉에서는 호품벼, 하이아미벼, 삼광벼의 완전미율이 85.2~88.3%의 범위로 다른 품종에 비하여 다소 높았으나, 고품벼를 제외한 나머지 품종간에 유의적인 차이는 없었다. 싸라기율은 하이아미벼, 삼광벼, 미품벼에서 7.5~8.5%의 범위로 다소 낮았고 윤기치는 미품벼에서 78로 다른 품종에 비하여 유의적으로 높았다. 철원에서 완전미율은 대보벼가 89.2%로 고품벼와 하이아미벼에 비하여 유의적으로 높았으며, 싸라기율, 심복백미 및 식미치 등은 품종간 뚜렷한 차이가 없었다. 이상의 결과를 종합해 볼 때, 강원지역 주요 농업지대별 적응성이 우수한 최고품질의 중만생종 품종에 있어서 평야지 춘천은 삼광벼, 하이아미벼 및 진수미벼, 동해안지 강릉은 대보벼와 칠보벼, 그리고 중간지 철원에서는 대보벼가 재배안전성과 환경적응성이 가장 우수하였다. Rural Development Administration has recently developed mid-late maturing rice cultivars with high quality. This study was conducted to select suitable mid-late maturing rice cultivar in major cultivation areas of Gangwon Province among domestic breeding cultivars for 2 years from 2013 to 2014. The average air temperature during the experiment in 2013 and 2014 was higher <TEX>$0.6{\sim}1.1^{\circ}C$</TEX> in Chuncheon, <TEX>$1.0{\sim}1.3^{\circ}C$</TEX> in Gangreung, and <TEX>$0.1{\sim}0.7^{\circ}C$</TEX> in Cheolwon than normal year. Precipitation in ripening period was higher 52.5 mm in 2013, but lower 176.4 mm in 2014 than normal year in Chuncheon, lower 103.1 mm in 2013 and higher 42.9 mm in 2014 in Gangreung, lower 225.9~322.7 mm in Cheolwon. Duration of sunshine in ripening period was higher 142 hours in Chuncheon, 108 hours in Gangreung, and 94 hours in Cheolwon than normal year in 2013, higher 20~21 hours in Chuncheon and Gangreung, and 82 hours in Cheolwon than normal year in 2014. Milled rice yield of 'Samgwangbyeo' and 'Daebobyeo' was 594 kg per 10a, and 578 kg for 'Jinsumibyeo' in Chuncheon in plain area. For Gangreung in east coastal area, the yield of 'Daebobyeo' was 555 kg per 10a, 'Hopumbyeo' was 554 kg, and 'Chilbobyeo' was 546 kg. For Cheolwon in mid-mountainous area, the yield was 504 kg per 10a for 'Daebobyeo' and 489 kg for 'Haiamibyeo'. But there was no difference in milled rice yield among cultivars tested in the study at each area. Head rice ratio of 'Haiamibyeo', 'Jinsumibyeo', and 'Mipumbyeo' in Chuncheon was 94.2~95.6% higher than the other cultivars. In Gangreung head rice ratio of 'Hopumbyeo', 'Haiamibyeo', and 'Samgwangbyeo' were 85.2~88.3% but there was no difference among cultivars except 'Gopumbyeo' and broken rice ratio of 'Haiamibyeo', 'Samgwangbyeo', and 'Mipumbyeo' were low as 7.5~8.5% and palatability of 'Mipumbyeo' was higher than the other cultivars. Head rice ratio of 'Daebobyeo' was the highest as 89.2% and there was no difference in broken and chalky rice ratio and palatability among cultivars in Cheolwon. Considering rice yield and quality in major cultivation areas of Gangwon Province, suitable mid-late maturing rice cultivars were 'Samgwangbyeo', 'Haiamibyeo', and 'Jinsumibyeo' in Chuncheon, 'Daebobyeo' and 'Chilbobyeo' in Gangreung, and 'Daebobyeo' and 'Haiamibyeo' in Cheolwon. The results obtained in the study imply that the selected cultivars with high yield and quality and suitability to Chuncheon, Gangreung, and Cheolwon, respectively could be recommended to rice cultivating farmers in the regions with high priority.

Relationship between rice grain quality traits and starch pasting properties using early maturing rice cultivars in Chungnam plain area

This study was conducted to know the variation and relationship of rice grain quality and starch pasting properties by transplanting times. Two early maturing rice cultivars which accounted for the most area of early maturing rice cultivar in Chungnam province were used. The experiment was laid out in a split-plot design with 3 replications. The main plot consisted of three transplanting times viz. early (April 25), ordinary (May 25) and late (June 25) with sub-plots containing two cultivars. According to the transplanting times, most of rice grain quality and starch pasting properties showed significant difference and Joami showed higher grain quality than Unkwang in all transplanting times. Especially, rice grain quality was improved when transplanted late, showing high head rice and glossiness of cooked rice due to the lower mean temperature during grain filling stage. Glossiness of cooked rice was positively correlated with head rice ratio, amylose content and setback value, and negatively correlated with chalky rice ratio and protein content. The highest positive and negative correlation were observed between breakdown value and peak viscosity (r = 0.98**), and breakdown and setback (r = -0.94**), respectively. These results provide some information for rice researchers and producers producing cultivars with an improved quality, suggesting that rice quality is highly influenced by temperature at grain filling stage, and transplanting times is crucial in improving rice quality. In addition, starch pasting properties are useful for determining rice quality because rice grain quality and starch pasting properties are dependent on each other.

Variation of Yield and Quality in Early Maturing Rice Cultivars by Transplanting Date in Chungnam Plain Area in Korea

Studies were initiated for two consecutive years to examine the effects of transplanting date on the yield and quality of early maturing rice cultivars and to select rice cultivars capable of adapting to early transplanting in the middle plain area. The experiment was laid out in a split-plot design with 3 replications. The main plots consisted of two transplanting dates viz. early (25th of April) and ordinary (25th of May), with sub-plots containing eight cultivars. For early transplanting the mean temperature at the grain filling stage was lower than for ordinary transplanting, while the rice grain quality traits and palatability values were improved. Early transplanting results in 11 days earlier heading, higher head rice yield and lower milled rice yield than ordinary transplanting. Significant differences among the eight cultivars tested in this study were observed for most traits. Among cultivars, ‘Joami’ demonstrated the highest palatability. ‘Joami’ also performed better in head rice ratio and head rice yield than ‘Unkwang’, which is widely cultivated in the middle plain area. Palatability value (PV) showed significant positive correlations with head rice ratio (HR) and amylose content (AC), and negative correlations with chalky rice ratio (CR) and protein content (PC). Mean temperature (MT) was positively correlated with CR and PC, and negatively correlated with HR and AC. The highest positive and negative correlations among the rice quality traits were observed between HR and AC (r = 0.734), and HR and CR (r = -0.944), respectively. Based on the research findings, ‘Joami’ is suitable for early transplanting for cultivation in the Chungnam plain area.

Methane mitigation for flooded rice paddy systems in South Korea using a process-based model

Rice (Oryza sativa L.) is one of the most important food crops in the world. However, rice paddy fields are considered as one of the major sources of anthropogenic CH4 emissions. The objectives of this study were to estimate CH4 fluxes from a rice paddy field during rice growing seasons in South Korea and to assess the impacts of water managements on reduction of CH4 emissions using a process-based model. Three CH4 flux monitoring chamber systems installed at a rice paddy field in Gimje (South Korea) were used to measure CH4 fluxes. These measured datasets were used to evaluate the performance of the Denitrification–Decomposition (DNDC) model to simulate CH4 fluxes. A mid-late maturing rice cultivar (Shindongjinbyeo) was transplanted with a planting density with 0.15 m × 0.30 m (hill × row) on June 21, 2012 and June 21, 2013 after barely had been harvested at the study site. The DNDC model underestimated CH4 fluxes from a rice paddy field at the beginning of the rice growing seasons (overall 0.7 of R2 for the year 2013), while the DNDC model well-estimated CH4 emissions during the rice growing seasons. The DNDC model was used to assess the impacts of continuous flooding and midseason drainage on CH4 emissions. This study suggests that the DNDC model can be used to assess efficacious mitigation strategies to reduce the greenhouse gases.