종자 건전성(seed health)은 종자 또는 식물체에 유익하지 못한 영향을 미칠 수 있는 생물체의 감염상태를 의미한다. 이들 생물체는 종자의 품질에 직접적인 피해를 줄 수 있으며,감염 종자는 식물체에 병을 유발하고 포장에서의 발병을 확산시킴으로써 대규모의 경제적 피해를 유발할 수 있다. 상업용종자의 해외증식 및 국제교역, 종자 유전자원의 해외분양 및 상호교환이 활발해짐에 따라 이러한 위험성이 더욱 커지고 있으며 더불어 종자 건전성 관리의 중요성 또한 증가하고 있다. 다양한 벼 종자 유전자원을 보존하고 연구용으로 분양하는 국제미작연구소(International Rice Research Institute, IRRI)는 유전자원의 건전성 확보를 위하여 종자건전성연구실(Seed health unit)을 두어 체계적인 관리시스템을 운영하고 있다. 필리핀 식물산업국 산하 식물검역소로부터 권한을 부여받아 필리핀 국내로 도입되거나 해외로 분양되는 유전자원에 대하여종자처리 및 건전성 모니터링, 종자 건전성 검사 및 데이터베이스 관리 업무를 수행하고 있다. 대상 병원균에 따라 육안검사, 수세현탁액 검사, 습지법 검사, 한천배지 검사 등을 적용하고 있으며, 감염종자는 온탕처리와 같은 물리적 처리와 살균제 또는 훈증제와 같은 화학적 처리를 수행한다. 국제미작연구소의 건전성 관리시스템을 우리나라 벼 종자 유전자원의보존·관리에 선별 적용하고, 더불어 종자소독방법과 저장 전관리체계를 확립함으로써 벼 유전자원의 품질을 제고할 수 있을 것이다. 또한 국제협력 및 공동연구 등 신뢰구축을 통해유용한 해외 유전자원을 확보하는 데 기여할 것으로 기대된다.

Little millet (Panicum sumatrense) is well known for its salt and drought stress tolerance and high nutritional value, but very limited knowledge of genetic variation and genomic information is available. In this study, a total of 779 primer pairs were designed from the 22,961 EST sequences of switchgrass (Pancium virgatum), of which 48 EST-SSR markers were developed based on the trials of transferability of these primers in little millet. The EST-SSR amplicons showed reproducible single band polymorphism and produced a total of 160 alleles with an average of 3.3 alleles per locus in 37 accessions of little millet. The average values of expected and observed heterozygosities were 0.266 and 0.123, respectively. The polymorphic information content (PIC) values were observed in range of 0.026 to 0.549 with an average of 0.240. The genetic relatedness among the little millet accessions was evaluated by neighbor-joining dendrogram, which grouped all accessions into two distinct groups. The validation thus demonstrated the utility of the switchgrass EST-SSR markers in assessing genomic relationships in little millet. The findings from this study could be useful for designing strategies for the identification of diverse germplasm for conservation and future molecular breeding programs for little millet.

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.

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.

Rice blast (Magnaporthe oryza B.) is one of the most widespread and devastating diseases of rice. Screening of valuable genetic resources harboring resistance genes is one of the most efficient approaches against blast disease. Because the bioassay to rice blast in the field shows high variations, this study has performed to provide DNA profiles in the accessions of diverse countries using major blast resistant genes linked markers, identified and mapped in different genotypes of rice. Because durable resistance to blast is controlled by a combination of major resistance genes, we surveyed the distribution of blast resistant genes in the 1,500 accessions using major 12 blast resistance genes linked markers. These resistant genes found that the frequency distribution of Pi-39 (66.9%), Pik-m (41.9%), Pit (40.5%), Pii (21%), Pib (19.3%), Pi-d(t)2 (12.7%), but Pita, Pita/Pita-2, Pik, Piz-t, Pi5 genes were identified in less than 10% frequency. Most of accessions contain from 1 to 4 different resistant genes. Pi39 and Pik-m genes amplified in the 69.1% and 51.7% among 356 Korean accessions, Pi39 (79.6%) and Pib (55.8%) in 113 China, Pit (80.6%) and Pib (32%) in 103 Philippines, respectively. In this study, we evaluated the blast resistance degree and the information about the distribution of rice blast resistant genes in rice germplasm. This study will help to develop effective strategies for managing rice blast disease in rice germplasm.

Rice genetic resources are composed of various species and ecotypes, and each accession reveals different genetic and phenotypic characters. For the managenment of diverse rice genetic resources, seed integrity is important factor in that the individuals of one accession in self-pollinating crop might be homogeneous. To elevate the management efficiency of rice germplasm contrary to the phenotypic distinction, we focused on applicable microsatellite markers because this markers are widly used for genetic evaluation in diverse genetic resources with a character of high reproducibility and polymorphism. In this regard, we selected microsatellite markers based on genotypes; diversity set including 150 accessions using 249 SSR markers. As SSR loci with high PIC(polymorphism information content) values usually revealed multi bands in one accession, proper genotyping were difficult in these loci. Therefor, we checked the band clarity in addition to PIC values and chose 12 and 6 SSR markers finally. All accessions of rice diversity set were distinguished with the first marker set comprising 12 SSR markers, and only 3 combinations of tested accessions(0.03%, 3/11,175) showed same genotype with second marker set comprising 6 SSR markers. The tested 142 Korean bred varieties revealed 0.19%(19/10,011 combinations) and 0.69%(69/10,011 combinations) genotypic identity using first and second marker set, respectively. These newly selected markers might be useful for the analysis of genetic homogeneity and relationship in rice genetic resources.

Soybean (Glycine max, 2n = 2x = 40) is broadly distributed throughout East and South East Asia, and important crop as a source of protein, oil, food and animal feed. In order to better understand the morphological differentiation of soybean germplasm collected from China, Japan, Korea, Philippines, America, we analyzed the morphological variabilities among 629 soybeans with 11 morphological traits, such as growth type, leaflet, flower color, trichome, seed coat color, color inside seed etc. and measured the fatty acid composition. The result of the principal coordinates analysis (PCoA) based on the 11 morphological traits revealed diversity among all accessions. The PCoA separated the accessions into two main groups, each group with distinctive features. Among tested germplasm, the contents of five fatty acids were as follows: linolenic acid (2.8%－16.23%), linoleic acid (27.4%－56.6%), oleic acid (9.2%－35.0%), stearic acid (2.9%－8.8%), and palmitic acid (8.7%－17.1%). The fatty acid composition has not shown significant variation among all accessions. IT 22268 was the highest linolenic acid composition (16.2%), while IT 154687 was the lowest (2.8%). Forty three of 629 accessions showed the arachidic acid (0.5%-3.6%), which is the saturated fatty acid with a 20 carbon chain and is as a minor constituent of peanut oil (1.1%-1.7%). This result of this characterization served as reliable resources for detailed description and new functional plant breeding of soybean varieties.

Kjeldahl method used in many materials from various plant parts to determine protein contents, is laborious and time-consuming and utilizes hazardous chemicals. Near-infrared (NIR) reflectance spectroscopy, a rapid and environmentally benign technique, was investigated as a potential method for the prediction of protein content. Near-infrared reflectance spectra(1100-2400 nm) of coarse cereal grains(n=100 for each germplasm) were obtained using a dispersive spectrometer as both of grain itself and flour ground, and total protein contents determined according to Kjeldahl method. Using multivariate analysis, a modified partial least-squares model was developed for prediction of protein contents. The model had a multiple coefficient of determination of 0.99, 0.99, 0.99, 0.96 and 0.99 for foxtail millet, sorghum, millet, adzuki bean and mung bean germplasm, respectively. The model was tested with independent validation samples (n=10 for each germplasm). All samples were predicted with the coefficient of determination of 0.99, 0.99, 0.99, 0.91 and 0.99 for foxtail millet, sorghum, millet, adzuki bean and mung bean germplasm, respectively. The results indicate that NIR reflectance spectroscopy is an accurate and efficient tool for determining protein content of diverse coarse cereal germplasm for nutrition labeling of nutritional value. On the other hands appropriate condition of cereal material to predict protein using NIR was flour condition of grains.