This study was carried out in Suwon-central plain, and Cheorwon, mid-northern plain of Korea to evaluate agricultural characteristics including heading date and yield component for North Korean rice germplasm. The difference between two regions of the heading dates of germplasm was recognized the significance and early matured group growing in Cheorwon tended to flower earlier than that of Suwon while mid-early matured group showed an opposite result. The other agricultural characteristics such as culm length, panicle length, number of panicles per hill, number of grains per panicle, and ripened grain ratio, of the two regions of all traits were highly significant, especially culm length and panicle length in Suwon were longer than those were growing in Cheorwon. Number of panicles per hill and number of grains per panicle in Suwon were more than that were growing in Cheorwon, and ripened grain ratio in Suwon was higher than that of Cheorwon. The another difference between both the regions, of 1000-grain weight was not significant while the effect of interaction between the regions and variety was highly significant. Whereas brown/rough rice ratio and milled rice yield were highly significant; higher in Cheorwon for brown/rough rice ratio and in Suwon of milled rice yield. Additionally, the results concluded that, the North Korean rice germplasm showed susceptible response to bacterial leaf blight(BLB) races such as K2. K3, and K3a but more than mid-range resistant response to rice blast.

농진청에서 수행하고 있는 아프리카 국제협력프로그램인KAFACI 사업의 일환으로 우간다 등 8개국에 ‘통일형 다수성벼 품종개발’ 사업을 추진하고 있다. 이를 위해 아프리카에서정상적인 생육과 수량을 나타내는 다수성 통일형 품종인 밀양23호와 아프리카의 재래종인 O. glaberrima를 이용하여 밀양23호의 유전적배경을 보유한 근동질 계통인 BC4F1을 육성하고, 약배양을 통해 유전적 고정계통을 육성하였다. 이 중 50개계통을 우간다에서 생물검정을 실시한 결과, 아프리카에서 문제시되는 Yellow Mottle Virus (RYMV), Bacterial LeafStreak(BLS), 흰잎마름병 및 도열병에 복합저항성인 계통으로판명되었다. 특히 RYMV에 대한 저항성은 저항성원이 결여되어 있는 병으로 본 연구를 통해 육성한 계통들은 향후 아프리카에 적응하는 내병성 다수성 품종개발에 유용한 재료를 활용 될 것으로 생각된다.

벼의 형태적·생태적 특성을 나타내는 주두색, 망색, 영색,종피색, 입장 및 입폭과 생태적 특성을 나타내는 종실의 탈립성, 배유형, 원산지 및 종실 건조특성이 4oC 저장고에 보존된벼 3,066점의 종자수명에 미치는 영향을 알아보기 위하여 그들의 상관관계를 분석한 결과는 다음과 같다.1. 벼 종자의 탈립성과 저장력과의 관계는 고도로 유의한(p<0.0001)정의 상관관계를 보였다. 탈립성이 강한 벼 종자일수록 종자수명이 길게 나타났다.2. 벼 종자의 입장이 길고, 입폭이 좁은 것일수록 종자수명이 길었다. 입장이 길고 입폭인 좁은 종자의 건조 특성은 같은 상대습도 조건에서 건조될 때 종자의 평형수분함량이 낮게나타났다. 3. 망색과 종자 저장력의 관계에 있어서 자주색 망을 가진자원이 종자수명이 긴 것으로 조사되었다.4. 종자 저장력에 영향을 끼치는 벼의 형태적·생태적 특성의 상대적 중요도는 탈립성이 50.2로 가장 컸고, 이어서 입장과 망색이 각각 21.9와 7.7로 분석되었다.

Meedon rice varieties are important for local adaptability, grain quality and market availability, and have been grown in Myanmar for centuries. Because of temporal variability and spatial heterogeneity, Meedon rice varieties in rainfed lowland areas may be diverse. However, information on diversity of Meedon rice germplasm is limited. This study was carried out to assess genetic diversity and to analyze population structure of Meedon rice germplasm conserved in Myanmar Seed Bank using SSR markers. For assessing genetic diversity, 154 accessions of Meedon rice germplasm were analyzed with nine SSR markers. A total of 86 alleles were detected with an average of 9.6 alleles per locus. All the loci were found to be polymorphic, and there were considerable genetic variation among accessions with mean values of expected heterozygosity (HE) = 0.5774 and polymorphic information content (PIC) = 0.5496. High frequency of rare alleles was identified, among which 35 unique (accession-specific) alleles were observed. Based on cluster analysis, rice accessions were mainly clustered into two groups, and as a result of model-based analysis, two distinct genetic populations and an admixture were classified. This result indicated that SSR markers have proved to be useful markers for detecting genetic diversity in Meedon rice, and the occurrence of a considerably high number of rare and unique alleles in the germplasm indicates their potentiality as a reservoir of rare genotypes for use. Unique alleles are also important because they may be diagnostic of a particular type of genotype for identification.

This study was carried out to build a database system for amylose and protein contents of rice germplasm based on NIRS (Near-Infrared Reflectance Spectroscopy) analysis data. The average waxy type amylose contents was 8.7% in landrace, variety and weed type, whereas 10.3% in breeding line. In common rice, the average amylose contents was 22.3% for landrace, 22.7% for variety, 23.6% for weed type and 24.2% for breeding line. Waxy type resources comprised of 5% of the total germplasm collections, whereas low, intermediate and high amylose content resources share 5.5%, 20.5% and 69.0% of total germplasm collections, respectively. The average percent of protein contents was 8.2 for landrace, 8.0 for variety, and 7.9 for weed type and breeding line. The average Variability Index Value was 0.62 in waxy rice, 0.80 in common rice, and 0.51 in protein contents. The accession ratio in arbitrary ranges of landrace was 0.45 in amylose contents ranging from 6.4 to 8.7%, and 0.26 in protein ranging from 7.3 to 8.2%. In the variety, it was 0.32 in amylose ranging from 20.1 to 22.7%, and 0.51 in protein ranging from 6.1 to 8.3%. And also, weed type was 0.67 in amylose ranging from 6.6 to 9.7%, and 0.33 in protein ranging from 7.0 to 7.9%, whereas, in breeding line it was 0.47 in amylose ranging from 10.0 to 12.0%, and 0.26 in protein ranging from 7.0 to 7.9%. These results could be helpful to build database programming system for germplasm management.

A statistical analysis for 3651 genetic resources collected from China (1,542), Japan (1,409), Korea (413), and India (287) was conducted using normal distribution, variability index value (VIV), analysis of variation (ANOVA) and Ducan’s multiple range test (DMRT) based on a data obtained from NIRS analysis. In normal distribution, the average protein content was 8.0%, whereas waxy type amylose and common rice amylose were found to be 8.7% and 22.7%, respectively. The protein contents ranged from 5.4 to 10.6% at the level of 95%. The waxy amylose and common rice amylose ranged from 5.9 to 11.5%, and from 16.9 to 28.5% at 95% confidence level, respectively. The VIV was 0.59 for protein, 0.64 for low amylose, and 0.81 for high amylose contents. The average amylose contents were 18.85% in Japanese, 19.99% in Korean, 20.27% in Chinese, and 25.46% in Indian resources, while the average protein contents were found to be 7.23% in Korean, 7.73% in Japanese, 8.01% in Chinese, and 8.17% in Indian resources. The ANOVA of amylose and protein content showed significant differences at the level of 0.01. The F-test for amylose content was 158.34, and for protein content 53.95 compared to critical value 3.78. The DMRT of amylose and protein content showed significant difference (p<0.01) between resources of different countries. Japanese resources had the lowest level of amylose contents, whereas, the lowest level of protein content was found in Korean resources compared to other origins. Indian resources showed the highest level of amylose and protein contents. It is recommended these results should be helpful to future breeding experiments.

Magnesium is important not only for the growth of rice itself, but also as an essential micronutrient component of half of the world population who are supported by rice. Here, we performed genome-wide association study (GWAS) with high-resolution density SNPs to identify natural allelic variation in Mg2+ increase from rice set, which is derived from a total 24,368 rice germplasms. The range of the concentration and distribution of Mg2+ in 295 core accessions of brown rice grain were wide, from 18.17mg/L to 57.11mg/L, with mean 39.71mg/L. In particular, GWAS result shows that the high peak found on chromosomes 3 and 11. The new natural variants identified through haplotyping analysis would be useful to develop new rice varieties with improved storage ability of the valuable mineral through the future molecular breeding.

This study was conducted to characterize the amylose and protein contents of 4,948 rice landrace germplasm using the NIRS model developed in the previous study. The average amylose content of the germplasm was 20.39% and ranged between 3.97 and 37.13%. The amylose contents in the standard rice were 4.99, 18.63 and 20.55% in Sinseonchal, Chucheong and Goami, respectively. The average protein content was 8.17% and ranged from 5.20 to 17.45%. Protein contents in Sinseonchal, Chucheong and Goami were 6.824, 6.869 and 7.839%, respectively. A total of 62% germplasm were distributed between 20.06% and 27.02% in amylose content. Germplasm of 81.60% represented protein content of 6.78-9.75%. The distinguishable ranges of amylose contents according to origin were 16.58-20.06% in Korea, 20.06-23.25% in Japan, 23.25-27.02% in North Korea, and 27.02-37.13% in China. In the protein content, approximately 30% of Chinese resources ranged from 9.75 to 17.45%, whereas less than 10% were detected in other origin accessions. Fifty resources were selected with low and high amylose ranging from 3.97-6.66% and 30.41-37.13%, respectively. Similarly, fifty resources were selected with low and high protein ranging from 5.20-6.09% and 13.21-17.45%, respectively. Landraces with higher protein could be adapted to practical utilization of food sources.

The objective of this research was to develop Near-Infrared Reflectance Spectroscopy (NIRS) model for amylose and protein contents analysis of large accessions of rice germplasm. A total of 511 accessions of rice germplasm were obtained from National Agrobiodiversity Center to make calibration equation. The accessions were measured by NIRS for both brown and milled brown rice which was additionally assayed by iodine and Kjeldahl method for amylose and crude protein contents. The range of amylose and protein content in milled brown rice were 6.15-32.25% and 4.72-14.81%, respectively. The correlation coefficient (R 2 ), standard error of calibration (SEC) and slope of brown rice were 0.906, 1.741, 0.995 in amylose and 0.941, 0.276, 1.011 in protein, respectively, whereas R 2 , SEC and slope of milled brown rice values were 0.956, 1.159, 1.001 in amylose and 0.982, 0.164, 1.003 in protein, respectively. Validation results of this NIRS equation showed a high coefficient determination in prediction for amylose (0.962) and protein (0.986), and also low standard error in prediction (SEP) for amylose (2.349) and protein (0.415). These results suggest that NIRS equation model should be practically applied for determination of amylose and crude protein contents in large accessions of rice germplasm.

Rice blast, caused by a fungus Magnaporthe oryzae, is one of the most devastating diseases of rice worldwide. Analyzing the valuable genetic resources is important in making progress towards blast resistance. Molecular screening of major rice blast resistance (R) genes was determined in 2,509 accessions of rice germplasm from different geographic regions of Asia and Europe using PCR based markers which showed linkage to twelve major blast R genes, Pik-p, Pi39, Pit, Pik-m, Pi-d(t)2, Pii, Pib, Pik, Pita, Pita/Pita-2, Pi5, and Piz-t. Out of 2,509 accessions, only two accessions had maximum nine blast resistance genes followed by eighteen accessions each with eight R genes. The polygenic combination of three genes was possessed by maximum number of accessions (824), while among others 48 accessions possessed seven genes, 119 accessions had six genes, 267 accessions had five genes, 487 accessions had four genes, 646 accessions had two genes, and 98 accessions had single R gene. The Pik-p gene appeared to be omnipresent and was detected in all germplasm. Furthermore, principal component analysis (PCA) indicated that Pita, Pita/Pita-2, Pi-d(t)2, Pib and Pit were the major genes responsible for resistance in the germplasm. The present investigation revealed that a set of 68 elite germplasm accessions would have a competitive edge over the current resistance donors being utilized in the breeding programs. Overall, these results might be useful to identify and incorporate the resistance genes from germplasm into elite cultivars through marker assisted selection in rice breeding.

Jungmo1019 early maturing rice variety was developed by the rice breeding team of the Department of Southern Crop, NICS, RDA in 2011. This cultivar was derived from the cross Hwayeongbyeo//Hitomebore/Nampyeongbyeo made in 2005 and the production of doubled haploid rice plant from anther culture in F1 generation. Testing in the replicated yield trial in 2008, a promising line YR25312Acp62 was selected and it was designated as the Milyang246. The early traus plauting local adaptability test of Milyang246 was carried out at three location in 2011 and it was named as Jungmo1019 showing a high head rice ratio and early–maturity eco-type. Number of spikelet/panicle and 1,000 grain weight of brown rice was slightly lower than those of Jopyeongbyeo. This variety is resistant to bacterial blight, rice stripe virus disease but susceptible to major insect and pests. The milled rice yield of Jungmo1019 is 4.52MT per ha at the early transplanting of the local adaptability test. This line should serve as a useful source for improving head rice ratio at early transplanting cultivation in southern plain area.

Bakanae (foolish seedling) disease caused by Gibberella fujikuroi creates serious problems in the foremost rice growing countries. This study was conducted to identify new resistance genetic sources to Bakanae disease. Bioassay showed that 11 varieties including Gwangmyeongbyeo, Hawn, Wonseadaesoo, Erguailai etc. were resistant to bakanae disease among 254 rice germplasm. Mismatch ratio between phenotype on bakanae disease bioassay and allele type of RM9, a SSR marker closely linked the bakanae disease resistant QTL, qBK1, were 38.3%. These results suggest that RM9 might be used for selecting qBK1, but it cannot be used for wide range of rice germplasm. Resistant germplasm in this study might be have resistant genes different from qBK1. The eleven varieties resistant to selected in this study will be used to identify new resistant alleles or genes to improve bakanae disease resistance in rice.

Low temperature germinability (LTG) is an important trait for breeding of varieties for use in direct-seeding rice production systems. Although rice (Oryza sativa L.) is generally sensitive to low temperatures, genetic variation for LTG exists and several quantitative trait loci (QTLs) have been reported. The objective of this study was to develop and employ high-efficiency molecular markers for evaluation of LTG in rice germplasm. A panel of japonica rice accessions (n=180) from temperate regions in Asia was evaluated for LTG and genotyped with markers from regions previously reported to harbor other LTG QTLs. ANOVA revealed that four markers on chromosome 2, 4, and 11 from previously reported QTLs showed highly significant value (p < 1.0e-04) and their R2 ranged 0.083 (qLTG11-1) to 0.190 (qLTG4b-1). An association analysis was conducted using SNP data generated by sequencing of the panel. Eight SNP markers were found to be significantly associated with LTG using general and mixed linear models. Three SNP-based CAPS and dCAPS markers from these results were developed and showed higher accuracy in predicting sensitive LTG germplasm. These new LTG markers will be useful for molecular evaluation of germplasm, particularly to identify sensitive or weak LTG accessions.

Rice (Oryza sativa L.) is one of the most important staple crops in the world, providing main energy source for more than half of the world’s population. It is even closely associated with economic and political stability in many developing countries of Asia and Africa. These days, moreover, amount of land suitable for the agriculture is shrinking due to a variety factors, such as rapid climate changes and industrializations, while rice eating human populations keeps growing. To meet the nutritional and socio-economic demands worldwide, dedicated efforts in developing superior rice varieties need to be reinforced, accumulating and combining beneficial alleles as much as possible from rice germplams. Here, we propose a pipeline for genome assisted breeding where new genomic technologies including GWAS, omics and evolutionary studies together with follow-up breeding programs are integrated. Once pinpointing candidates genes, the integrated genomics approach allows informed choice of parents for the following breeding program based on the haplotype information, in addition to providing precise molecular marker information. We also conducted proof-of-concept analysis, using various agriculturally important phenotypes for rice improvements.

Among the diverse crops, rice (Oryza sativa L.) has been domesticated as a staple carbohydrate sources mainly in Asia region, and RDA Genebank at the National Agrobiodiversity Center (NAAS) has conserved about 37 thousand rice accessions accordingly. Seed dormancy, one of domesticated traits, prevents pre-harvest sprouting (PHS) which causes degradation of grain quality in cereal crop. In previous study, we surveyed the variation of seed germinability of diverse 200 rice germplasm and detected the three distinguished groups besides admixed types; the first group (G-1) revealed high germinability at harvesting time, and the second group (G-2) and third group (G-3) acquired high germnability subsequent to after-ripening and dormancy breaking process, respectively. To reduce environmental effects on detected variation of germinability, we selected representative 14 accessions which have similar heading date of each group and measured the degree of PHS using freshly harvested panicles. Variation of PHS showed similar tendency of germinability group; generally, high PHS for G-1, low PHS for G-2 and no PHS for G-3. To resolve genetic and physiological factors concerning on PHS and seed dormancy, we checked the change and variation of ABA known for critical regulator for seed dormancy, and high PHS accessions interestingly revealed high ABA content in 10 DAF. Based on these study, we plan to analyze genetic factors affecting the degree of seed germinability and PHS.

The purpose of this study was to develop the cost-effective and efficiency seed longevity prediction method of rice (Oryza sativa L.) germplasm for viability monitoring. To find an optimum predicting method for rice seed longevity at genebank, an accelerated ageing (AA) test, a controlled deterioration (CD) test and a dry-heat treatment (DHT) were conducted to the four groups of rice germplasm based on ecotype, such as Indica, Japonica, Javanica and Tongil type. Among the three artificial aging treatments, the dry-heat treatment of 36 hours at 90°C is suggested as a routine predictive test method of rice germplasm longevity at a genebank. The distribution of germination rate on 3,066 accessions which conserved 26.5 years at 4°C showed similar trend with the result of distribution by dry-heat treatment at 90°C on 36 hours using 106 accessions of rice selected samples which composed four ecotype groups. The results show that the dry-heat treatment affect not only predicting the rice seed longevity but also determining effective interval for monitoring germination of rice germplasm in genebanks.

The purpose of this study was to know the seed longevity of rice (Oryza sativa L.) germplasm for effective viability monitoring. The longevity was determined via germination tests of 3,066 accessions of rice germplasm from the National Agrobiodiversity Center, Rural Development Administration, Korea. The rice germplasm accessions have been conserved at a mid-term storage (4°Csealed metal can on either sides for 25~26.5 years. The final germination percentages of 3,066 rice germplasm accessions of 6.5±1.0% seed moisture content with 94% initial germination stored at 4°C for 26.5 years declined to 47% while at -18°C for 25 years maintained high germinability as 93%. Germination time courses, which represent the average performance of rice ecotypes stored at 4°C and 30% RH, were fitted regression equation, to calculate the time at which germination characteristically declined to 50% (P50). These P50 values of Indica, Japonica, Javanica and Tongil type in rice were 39.9, 22.9, 25.4 and 31.8 years, respectively. The rice germplasm stored at 4°C could be clustered in 4 groups using quartile of final germination after 26.5 years storage. The seed longevity (P50) of each group was estimated by regression equation of changed germination percentages according to storage periods. The P50 values of group Ⅰ, group Ⅱ, group Ⅲ and group Ⅳ were 21.1, 23.6, 30.0 and 75.7 years.

Eating and cooking qualities are the most important trait in japonica rice breeding program in Korea. More improvements in grain quality to meet the demand of consumers are needed to develop new rice germplasm of high grain quality. In this study, we performed genetic analysis and grain quality evaluation in 96 Korean japonica rice germplasm including 26 varieties with 4 Japanese japonica high eating quality, 24 landraces, 22 weedy rices, and 14 breeding lines. These germplasm were analyzed using 13 DNA markers related to eating quality to conjecture the palatability of cooked rice (Lestari et al. 2009). Most varieties of high eating quality were clustered with germplasm of high expected quality (eq) varieties of similar genetic background of pedigree. The expected quality (eq) values of high eating quality varieties, Gopum, Ilpum, Samgwang, and Sugwang were 99.6∼104.5, and Koshihikari was 103.5. The eq of two weedy rices, Hoengseongaengmi 3 and Namjejuaengmi 6 were 101.9 and 101.6, respectively. However, Haiami of high eating quality was clustered with 15 weedy rice and 11 landrace germplasm of low eq value. The eq values of Haiami and Wandoaengmi 6 were 66.9 and 40.8, respectively, but they has 2 and 3 of palatability of cooked rice, and 73.6 and 78.6 of glossiness of cooked rice, respectively. We expect these germplasm would be new source for rice grain quality to develop japonica rice of high eating quality.