, Jeonghwan Seo, Songhee Park, Jae-Ryoung Park, Keon-Mi Lee, O-Young Jeong In the present study, we conducted a detailed analysis of the genetic diversity and structural organization of 96 domestic Korean rice varieties (
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‘Amissal’ is a regionally specialized rice cultivar developed to strengthen the competitiveness of local rice and is characterized by its distinct long-grain
To diversify the grain quality characteristics of Korean varieties of japonica rice (
The intermediate breeding material ‘JJ625LG’ was developed to diversify the grain shape characteristics of Korean
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‘Boramchan’ is a high-yielding, mid-late maturing temperate
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Risotto is an Italian rice dish cooked in broth until it reaches a creamy consistency. This is one of the most common rice preparation methods in Italy. The famous rice varieties for risotto are ‘Carnaroli,’ ‘Arborio,’ and ‘Vialone Nano.’ This study was conducted to provide essential data for breeding risotto rice varieties suitable for Korea by analyzing the agricultural traits of three risotto varieties and ‘Cheolweon96’ (Carnaroli SA-mutant line) under Korean environmental conditions. The risotto varieties and the mutant line showed early maturation, similar to ‘IS592BB.’ They had longer culm lengths and fewer panicles per hill and spikelets per panicle than to the Korean rice varieties, ‘i.e., Sindongjin’ and ‘IS592BB.’ They also exhibited lower ratios of ripened grains, brown/rough rice ratios, and lower yields. The risotto rice varieties and the mutant line other than ‘Vialone Nano,’ represented longer, wider, and heavier grain characteristics. The rice varieties and the mutants line had high levels of chalky rice, which absorbs water rapidly during cooking. Because broth absorption is important in risotto preparation, chalkiness can be considered an important characteristic of risotto rice varieties. In the analysis of pasting properties, ‘Carnaroli,’ ‘Cheolweon96,’ and ‘Vialone Nano’ showed similar characteristics, whereas ‘Arborio’ was grouped with ‘IS592BB.’ The cooked rice of ‘Carnaroli,’ ‘Cheolweon96,’ and ‘Vialone Nano’ exhibited a hard and non-sticky texture, while that of ‘Arborio’ was softer and stickier than that of the Korean rice varieties. The risotto rice varieties showed a larger grain size, higher chalkiness, pasting temperature, setback viscosity, and harder texture than the Korean rice varieties. These characteristics are expected to be useful selection indicators for breeding Korean risotto rice varieties.
‘Chamdongjin’ is a rice cultivar with a distinctively large grain size and good palatability, similar to ‘Sindongjin,’ which is a mega-cultivar in Korea. ‘Younghojinmi’ is a rice cultivar known for having the highest taste value among premium quality cultivars. In this study, we conducted quantitative trait loci (QTL) analysis of quality-related traits using recombinant inbred lines (RILs) derived from a cross between ‘Chamdongjin’ and ‘Younghojinmi’ to elucidate their genetic interactions. We analyzed 20 traits, including protein content, amylose content, glossiness of cooked rice, 7 traits related to grain appearance, 6 traits related to pasting properties, and 4 traits related to texture. Quality-related QTL were primarily detected on chromosome 3. In particular,
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Rapid climate change has diversified the dynamics of brown planthoppers, necessitating the development of rice cultivars with enhanced resistance. Brown planthoppers contribute to reduced grain yield and quality, and the rapid ecological changes caused by global warming are expected to exacerbate this damage. In Korea, rice cultivars resistant to brown planthoppers have primarily been bred using
The rice cultivar ‘JJ644wx’ was developed to improve disease resistance and lodging tolerance of Korean
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Recently, crossbreeding between Asian rice (
The rice cultivar ‘Chamdongjin’ exhibits a distinctively large grain size and excellent eating quality but is weak with regard to pre-harvest sprouting (PHS), requiring genetic improvement. In contrast, the premium-quality rice cultivar ‘Younghojinmi’ exhibits strong PHS tolerance. This study conducted quantitative trait loci (QTL) analysis on PHS and low-temperature germinability (LTG) using recombinant inbred lines derived from a cross between ‘Chamdongjin’ and ‘Younghojinmi’ to elucidate the genetic factors. Thus, an elite line with improved PHS tolerance was selected. QTL analysis revealed that
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‘Saebonghwang’ was developed as a mid-late ripening rice variety with good cultivation stability and yield in transplanting and under direct seeding cultivation. It was bred by backcrossing ‘Hopum’, which has excellent cultivation stability and adaptability to direct seeding, as a repeat parent, and ‘Hitomebore,’ a Japanese rice variety with excellent taste, as a donor. The heading date of ‘Saebonghwang’ was August 11 under ordinary planting, which is two days earlier than that of ‘Nampyeong’, and August 13 under wet-direct seeding cultivation, which is the same as that of ‘Dongan’. ‘Saebonghwang’ had a culm length of 74 cm under wet-direct seeding cultivation, which is larger than that of ‘Dongan’ (69 cm), and had good cultivation stability, including lodging resistance. ‘Saebonghwang’ is resistant to bacterial leaf blight and rice stripe virus and shows moderate resistance to rice blast. Furthermore, ‘Saebonghwang’ has better grain appearance, superior taste and better milling characteristics than ‘Nampyeong’. The yield of ‘Saebonghwang’ when cultivated under ordinary planting, wet-direct seeding, and double cropping was 5.65, 5.37, and 5.37 MT/ha, respectively. Under wet direct sowing by drone cultivation, ‘Saebonghwang’ showed good initial survival rate and cultivation stability. The yield was 4.49 MT/ha, slightly lower than that obtained under transplanted cultivation (5.03 MT/ha), but was not statistically different; therefore, ‘Saebonghwang’ was adjudged to be adaptable to drone wet-direct seeding. ‘Saebonghwang’ can be used in various ways to suit the working conditions of farms, increase farm work efficiency, and expand the area of wet direct-seeding cultivation (Registration No. 9171).
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‘Chamdongjin’ is a near-isogenic line with enhanced disease resistance compared to ‘Sindongjin,’ a mega-cultivar in Korea. ‘Younghojinmi’ is the rice cultivar with the highest taste quality among the premium cultivars. This study conducted quantitative trait loci (QTL) analysis on yield-related traits using the recombinant inbred lines derived from a cross between ‘Chamdongjin’ and ‘Younghojinmi’ to elucidate genetic interaction. We utilized KASP markers and a target-capture sequencing SNP genotyping platform to address the insufficient genetic diversity of the population using Korean
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The rice cultivar ‘Namchan’ was developed to achieve high yields under low-nitrogen fertilizer conditions and enhance cultivation stability. ‘Namchan’ was derived from a cross between ‘Nikomaru’, a Japanese rice cultivar known for its excellent ripening ability in high-temperature conditions, and ‘Saenuri’, a Korean mega rice cultivar renowned for its high cultivation stability. To shorten the breeding period, anther culture was applied to F1 plants. ‘Namchan’ was selected through the pedigree method, yield trials, and local adaptability tests, with high selection pressure for ripening ability and cultivation stability. The heading date of ‘Namchan’ was August 16, four days later than that of ‘Nampyeong’. ‘Namchan’ exhibited strong tolerance to lodging and preharvest sprouting, indicating high cultivation stability. Despite having more grains and panicles compared to that in ‘Nampyeong’, ‘Namchan’ exhibited excellent ripening ability, presumed to be inherited from ‘Nikomaru’. ‘Namchan’ showed intermediate resistance to rice blast and resistance to bacterial blight and rice stripe virus. ‘Namchan’ had excellent grain appearance, improved milling performance, and superior taste compared to ‘Nampyeong’. ‘Namchan’ exhibited a yield of 6.34 MT/ha under normal nitrogen fertilizer conditions, and its index at 115%, when compared to that of ‘Nampyeong’, is the highest among Korean japonica rice varieties. It exhibited a high yield of 5.45 MT/ha even under low-nitrogen fertilizer conditions. ‘Namchan’ is promising as an outstanding cultivar that can contribute to carbon neutrality through the reduction of nitrogen fertilizers and greenhouse gases (Registration No. 8134).
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The cultivated area of glutinous rice in the Homan Plain of Korea is increasing to diversify the cropping system. Depending on the time of transplanting, glutinous rice can be divided into early, ordinary, and late cultivation. Eight glutinous rice cultivars (Baegseolchal, Baekogchal, Boramchal, Boseogchal, Dongjinchal, JJ644wx, Nunbora, and Sinseonchal) were used to evaluate yield, pasting properties, and texture according to cultivation time and to analyze the genotype-environment relationship. There were nine yield-related, six pasting-related, and four texture-related traits studied. Heading date and culm length were shortened as cultivation time increased, while panicle length, number of spikelets, and 1,000-grain weight increased. Furthermore, late cultivation time also reduced pasting properties, peak viscosity, trough viscosity, and final viscosity. Hardness and adhesiveness among the texture properties increased with cultivation time, but stickiness decreased. The variation in 1,000-grain weight is mostly dominated by genotype, whereas heading date and yield are heavily influenced by environmental factors. All pasting property characteristics varied with environment changes, and genotype variation was dominant for all texture properties. Boramchal yielded the most in early and ordinary cultivation and Sinseonchal, together with Boramchal, yielded the most in late cultivation. Cultivars with excellent grain quality were Sinseonchal in early cultivation and Baegseolchal and Baekogchal in ordinary and late cultivation. A comparative analysis of characteristics based on cultivation time can assist in the selection of glutinous rice suitable for the Honam Plain and in the breeding of cultivars with improved yield and excellent grain quality.
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The rice cultivar ‘Chamdongjin’ was developed to enhance the disease resistance of ‘Sindongjin’. ‘Sindongjin’, developed by the RDA in 1999, is a mega-variety with a unique grain size and excellent taste, and has been cultivated in the largest area in Korea since 2018. As ‘Sindongjin’ has been cultivated in a large area recently, problems such as pest damage are increasing, and the necessity to develop alternative cultivars is emerging. Accordingly, the multiple disease-resistant, mid-late maturing rice cultivar ‘Chamdongjin’, carrying the bacterial blight resistance gene
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“JJ603Balck” is a mid-late maturing high-yielding black rice having multiple-disease resistance. It was developed to increase the yield and disease resistance of Korean black rice. “JJ603Black” was derived from a cross between “Heughyang” and BC2F1 plants (Hopum*3/SR30075-1-12-6-1-1-1). “Heughyang” is a mid-late black rice with a short culm, while “Hopum” is a mid-late maturing rice cultivar with high yields and premium quality, and “SR30075” is a pyramid line carrying three bacterial blight resistance genes. “JJ603Black” was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for black pericarp, resistance to bacterial blight K3a race, and high yield performance. The heading date of “JJ603Black” was August 19, 8 d later than that of “Heugnam,” which is the standard cultivar for black rice. “JJ603Black” is a cultivar tolerant to lodging with erect plant architecture. It showed multiple-disease resistance against bacterial blight and rice stripe virus owing to introgression resistance genes,
Rice blast is one of the most serious agricultural diseases in the world. Rice blast can be managed using low nitrogen fertilizers, treatment with chemical fungicides, and the most effective resistant varieties. Many genetic resources have been investigated and used along with molecular markers to breed blast-resistant rice varieties. In this study, the genetic diversity of blast resistance genes using 27 functional/linked markers and rice blast incidence over three years was investigated in 296 Korean rice varieties. Blast incidence was determined using a 0-9 scoring system (0=no lesions to 9=dead leaves) in nursery tests. The blast incidence of 296 rice varieties showed a significant correlation between years (
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Temperate
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Interspecific and intersubspecific crosses have been an important strategy for rice breeding programs to obtain useful characters by expanding genetic diversity. However, the wide cross routinely causes undesirable characters in rice, such as spikelet sterility and poor quality. In this study, we developed near-isogenic lines of
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‘Jonong’ is an early maturing whole crop silage (WCS)
Rice is the most important staple food in Korea. Rice blast, caused by
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The damage caused by typhoons to rice production has been increasing. To reduce this damage, wind-tolerant rice breeding programs have been conducted at the Yeongdeok substation (YS) of the National Institute of Crop Science (NICS). This study was conducted to examine the effects of these wind-tolerant rice breeding programs. Under the wind-tolerance screening facility (WTSF), the wind-tolerance of 17 rice varieties bred at NICS (usual rice) and 20 rice varieties bred at YS (wind-tolerant rice) were analyzed by evaluating six traits: white spikelet (WS), white panicle (WP), degree of wind damage (DG), ratio of ripened grain (RRG) at control (RRG_C) and treatment (RRG_T), and reduction rate of RRG between control and treatment (RRG_R). Wind-tolerant rice showed more wind-tolerant characteristics than usual rice, such as lower WS, WP, DG, and RRG_R and higher RRG_T and RRG_C. In the principal component analysis, wind-tolerant rice showing a similar direction for RRG_T and RRG_C were located separately from the usual rice. The adaptability tests of wind-tolerant rice were conducted by evaluating eight yield-related traits in the wind-prone areas. Wind-tolerant rice was divided into three clusters by K-means clustering analysis using WP and RRG_T with the WTSF, RRG, and yield in the wind-prone areas. Among the three clusters, YC2 had the strongest wind tolerance performance, followed by YC3 showing moderate wind tolerance, and YC1 the weakest wind tolerance. ‘Sinbo’, a variety belonging to YC2, exhibited the strongest wind tolerance and high yield potential among all varieties. The wind-tolerant rice varieties bred at YS could be used practically to prevent wind damage and utilize breeding materials to enhance the wind tolerance of rice varieties.
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Early maturing rice is widely utilized to diversify cropping systems in the Honam Plain, Korea. It is based on the principle of a short growth duration. There is concern regarding quality deterioration of early maturing rice owing to the high temperature during the ripening stage as compared to that for mid and mid-late maturing rice. This study was conducted to analyze six pasting property-related and eight quality traits of six early maturing rice varieties (Jopyeong, Odae, Unkwang, Haedamssal, Jinkwang, and Haedeul) on early, ordinary, and late cultivations, and to interpret the relationships between genotypes and environments. As the cultivation time increased, the ratio of head rice (HR) and glossiness of cooked rice (Toyo value, TY) increased. The cumulative mean temperature of the ripening stage showed a strong negative correlation with HR and TY at all cultivation times. Pasting temperature, peak viscosity (PV), trough viscosity, final viscosity, and breakdown (BD) decreased, whereas setback (SB) increased as the cultivation time was delayed. Pasting properties were affected more by climate conditions in the ripening stage than during the growth stage. Additive main effects and multiplicative interaction analysis revealed that pasting property-related and quality traits were affected more by environment than genotype. Jinkwang and Haedamssal in early and ordinary cultivation and Jinkwang and Haedeul in late cultivation exhibited higher HR and TY and a lower protein content. They also showed higher PV and BD and lower SB, which are characteristics of good eating quality japonica rice. Jinkwang, Haedamssal, and Haedeul are premium-quality, early maturing rice varieties that were recently developed. The cultivation of these varieties could improve the grain quality of early maturing rice at high temperatures during the ripening stage in the Honam Plain.
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The cultivation of early maturing rice in the plain areas in Korea is increasingly diversifying its cropping systems. Early maturing rice cultivars are usually vulnerable to bacterial blight (BB) and rice stripe virus (RSV) compared to mid- and mid-late maturing rice cultivars. To enhance the resistance of early maturing rice against BB and RSV, ‘IS592BB’ was developed by introgression of resistance genes,
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Recent advances in high-throughput sequencing technologies have enabled large-scale cost-effective genotypic analyses, and consequently, obtaining reliable phenotypic data has now become a major bottleneck in data-driven plant breeding. In order to construct a phenotype database for commercial rice varieties released by the National Institute of Crop Science, Rural Development Administration, we initiated a systematic phenotype evaluation project, with the aim of investigating the major agronomic traits of Korean rice varieties released during the period between 1979 and 2017. Despite the narrow genetic background, we found that the days to heading (DTH) and culm length (CL) of the 297 Korean rice varieties assessed exhibited wide phenotypic variation under different environments. Under normal planting cultivation in 2018, the DTH ranged from 48 to 104 days in Suwon, 46 to 111 days in Wanju, and 39 to 97 days in Miryang, with CL values ranging from 59 to 134 cm, 55 to 122 cm, and 57 to 106 cm, respectively. During early planting cultivation in 2019, the DTH ranged from 56 to 113 days (Suwon), 58 to 109 days (Wanju), and 58 to 100 days (Miryang), with corresponding CL values ranging from 63 to 119 cm, 55 to 93 cm, and 51 to 115 cm. Despite the difference of one month in planting dates in 2018 and 2019, DTH in the different years and regions showed highly significant positive correlations (r=0.90-0.98), whereas CL showed positive but weaker correlations (r=0.45-0.82). Furthermore, we detected a weak, although significant, correlation between DTH and CL in each environment (r=-0.18-0.35). Analyses of additive main effects and multiplicative interaction (AMMI) were conducted for DTH and CL to identify rice varieties with stable phenotypes under different environments. We anticipate that the findings of this study will provide a useful rice phenotype database to facilitate genotype-phenotype association studies and data-driven rice breeding.
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The cultivation of early maturing rice in the Honam plain area of Korea is increasing to diversify the cropping systems. The cropping systems of this rice are usually classified as early, ordinary, and late cultivations based on transplanting time. The characteristics of varieties vary depending on the cultivations. To evaluate the performance of varieties and interpret the relationships between genotype and environment, nine yield and 17 panicle-related traits of six early maturing rice varieties (Jopyeong, Odae, Unkwang, Haedamssal, Jinkwang, and Haedeul) were characterized on early, ordinary, and late cultivations. Heading date was longer in order of early, ordinary, and late cultivations. The cumulative mean temperature of growth stage was similar for all cultivations. The variation in the number of spikelets per panicle (NS) was mainly due to the variety and the traits related with secondary rachis-branch were affected more by variety than the traits related to primary rachis-branch. The varieties with the highest yield were Haedamssal on early maturing cultivation and Unkwang on ordinary and late cultivations. Haedamssal displayed a panicle-number type plant architecture with relatively higher number of panicles per hill (PN) and average NS. Unkwang exhibited panicle-weight type with many NS and less PN. Additive main effects and multiplicative interaction analysis revealed that, NS and HD were mostly affected by genotype and environment, respectively. Among yield-related traits, NS contributed the most to enhanced yield of varieties in all cultivations. NS could be the target trait of breeding programs intended to improve the yield potential of early maturing rice adaptable to the Honam plain area. However, proper PN should be considered because PN, which was negatively correlated with NS, also affected the yield.
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Rice research in Korea during the past 100 years has gone through tremendous changes and improvements as the country underwent a turbulent history of transformation. Full-scale R&D modernization began in the 1970s, when the government focused policy on achieving self-sufficiency in rice in order to establish the foundation for national economic growth. A major landmark was reached by the development of the rice variety “Tongil” and its cultivation technology, which was at the core of the unprecedented Korean “Green Revolution”. Since achieving self-sufficiency in rice, the breeding goal of Korea moved from increasing yield to improving grain quality as more consumers began to seek high quality food products in the 1980s. This change led to the establishment of the high quality rice breeding platform for enhancing the global competitiveness of Korean rice to cope with the opening of domestic rice market in the 2000s. Currently, the major breeding goals in rice are developing premium quality cultivars for table rice and specialized cultivars for boosting processed food industry. To date, the National Institute of Crop Science has released a total of 300 rice cultivars, including 202 table rice and 98 specialized usage cultivars. Diverse technologies have been developed and utilized for breeding new rice cultivars to meet changing needs. In the next 100 years of rice breeding, the convergence of traditional crop improvement technologies and the new breeding technologies utilizing recent advances in biotechnology will play a crucial role in enhancing breeding efficiency.
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‘Yechan’ is a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance. It was a derived from a cross between ‘Hopum’ and ‘Iksan537’ (cultivar name ‘Haepum’). ‘Hopum’ is a high grain quality mid-late maturing rice cultivar with strong lodging tolerance and ‘Haepum’ is a high grain quality medium maturing rice cultivar with multiple disease resistance. To shorten the breeding period, another culture method was applied to the F1 plants. ‘Yechan’ was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for grain quality, lodging, and disease resistance. The heading date of ‘Yechan’ was August 14, one day later than that of ‘Nampyeong’. ‘Yechan’ is a cultivar tolerant to lodging and it has short culms. It has multiple disease resistance against rice blast, rice stripe virus, and bacterial blight, including the K3a race, the most virulent race in Korea. The yield of ‘Yechan’ was similar to that of ‘Nampyeong’. ‘Yechan’ showed excellent grain appearance, superior taste when cooked, and enhanced milling performance; thus, we concluded that it could contribute to the improvement of Korean
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