야생벼는 재배벼의 병해충 저항성과 불량환경 적응성 등을 제고할 수 있는 유용한 유전자원으로 평가되고 있다. 농촌진흥청 국립식량과학원에서 국내육성 자포니카 벼 품종인 ‘화성’과 야생벼 O. minuta (BBCC 게놈; Acc.=101141)간의 종간교잡을 통하여 흰잎마름병과 도열병에 저항성인 ‘수원506호’를 육성하였으며, 본 계통에 대한 야생벼 유래 도열병 저항성 유전자의 유전양상 구명 및 유전자위 표지에 대한 연구결과는 다음과 같다.1.반복친인 ‘화성’에 높은 친화성을 발현하는 6개 도열병 균주 검정에서 ‘수원506호’는 반복친 ‘화성’과 5개 비교품종들과 다른 저항성 반응을 보여 이들과 다른 야생벼 유래 도열병 저항성 유전자를 보유하는 것으로 판단되었다.2.분자마커의 유전자형과 도열병 저항성 간의 연관성평가를 수행한 결과, ‘수원506호’의 도열병 저항성에 관여하는 주동유전자위는 12번염색체 중단의 RM101-S10704-RM1337 좌위에 위치하는 것으로 추정되었다.3.STS 마커 S10704에서 확인된 ‘화성’과 ‘수원506호’의 이질적인 유전자형은 해당부위에 야생벼 O. minuta의 염색체 단편이 이입되었다는 것을 증명하였다.4.이 좌위는 적어도 9개의 도열병 저항성 유전자들이 위치하는 것으로 보고된 바 있는데, 추후 정밀분석을 통해 ‘수원506호’의 도열병 저항성 유전자위와 기 보고된 유전자들과의 관계를 분석할 계획이다.

NGS costs are decreasing rapidly, and beneficial application of the technology to plant genomics seems inevitable. Trying to interpret the agriculturally important traits like yield is actively in progress all across the globe. However, the current stage of bio-informatic technology as applied to the interpretation of agricultural trait appears not yet at a level of maturity to justify widespread plant genome sequencing for user-friendly molecular breeding. It is necessary to construct dense mutation block (DMB) based molecular breeding system for selecting plants with optimal agricultural performance; as well as for identifying useful quantitative trait loci (QTLs). Firstly, we screened and selected DMBs-specific INDEL markers obtained from SNV density profiles using 42 genome sequences of Korean cultivar and public sequences of 24 japonica rice cultivars. Secondly, we analyzed the genetic similarity between 288 Korean cultivars using 113 DMB-specific INDEL markers, which could differentiate on agarose gel by PCR. And we are going to integrate 360 INDEL markers up to 30 per each chromosome. Finally, we selected 40 founder lines considering the importance of the breeding, the purpose of use, and plant ecotype. To construct rice nested association mapping population we crossed each founder lines with the pollen of Hwayoungbyeo which was most commonly used in korean rice breeding program. F2 seed multiplication and generation iteration are ongoing.

Rice transformation method using A. tumefaciens has already been widely used to generate transgenic plants, the transformation rate is still low in most Korean elite cultivars. We made several modifications of the standard protocol especially in the co-cultivation step to improve the efficiency of the rice transformation. The co-culture medium was modified by the addition of three antioxidant compounds (10.5㎎/ℓ L-cysteine, 1mM sodium thiosulfate, 1mM dithiothreitol) and of Agrobacterium growth-inhibiting agent (5㎎/ℓ silver nitrate). Co-cultivation temperature (23. 5℃ for 1 day, 26.5℃ for 6 days) and duration (7 days) were also changed. The plasmid of pMJC-GB-GUS carrying the GUS reporter gene and the bar gene as the selectable marker was used to evaluate the efficiency of the transformation. After co-cultivation, a high level of GUS gene expression was observed in calli treated with the modified method. It is likely that those newly added compounds helped to minimize the damage due to oxidative bursts during plant cell-Agrobacterium interaction and to prevent necrosis of rice cells. And the transformation rate under the modified method was also remarkably increased approximately 8-fold in Heungnambyeo and 2-fold in Ilmibyeo as compared to the corresponding standard method. Furthermore, we could produce the transgenic plants stably from Ilpumbyeo which is a high-quality rice but its transformation rate is extremely low. Transformation and the copy number of transgenes were confirmed by PCR, bar strip and Southern blot analysis. The improved method would attribute reducing the effort and the time required to produce a large number of transgenic rice plants.

Rice transformation method using A. tumefaciens has already been widely used to generate transgenic plants, the transformation rate is still low in most Korean elite cultivars. We made several modifications of the standard protocol especially in the co-cultivation step to improve the efficiency of the rice transformation. The co-culture medium was modified by the addition of three antioxidant compounds (10.5㎎/ℓ L-cysteine, 1mM sodium thiosulfate, 1mM dithiothreitol) and of Agrobacterium growth-inhibiting agent (5㎎/ℓ silver nitrate). Co-cultivation temperature (23. 5℃ for 1 day, 26.5℃ for 6 days) and duration (7 days) were also changed. The plasmid of pMJC-GB-GUS carrying the GUS reporter gene and the bar gene as the selectable marker was used to evaluate the efficiency of the transformation. After co-cultivation, a high level of GUS gene expression was observed in calli treated with the modified method. It is likely that those newly added compounds helped to minimize the damage due to oxidative bursts during plant cell-Agrobacterium interaction and to prevent necrosis of rice cells. And the transformation rate under the modified method was also remarkably increased approximately 8-fold in Heungnambyeo and 2-fold in Ilmibyeo as compared to the corresponding standard method. Furthermore, we could produce the transgenic plants stably from Ilpumbyeo which is a high-quality rice but its transformation rate is extremely low. Transformation and the copy number of transgenes were confirmed by PCR, bar strip and Southern blot analysis. The improved method would attribute reducing the effort and the time required to produce a large number of transgenic rice plants.

Near-isogenic lines (NILs) carrying bacterial blight resistance genes (Xa4, xa5 and Xa21) were developed in japonica rice using Suweon345 as genetic background. NILs were selected by gene specific DNA markers and inoculation of K1 or K3a race. NILs conferring Xa4 were resistant to K1, K2, K3, and moderately resistant to K3a. NILs conferring xa5 were resistant to K1, K2, K3, and K3a. NILs having Xa21 were susceptible to K1, while resistant to K2, K3 and K3a. Target genes of NILs with the genetic background of Suweon345 were also confirmed by using eleven Philippines races and International Rice Bacterial Blight (IRBB) NILs carrying Xa4, xa5 and Xa21. All NILs had no significant difference from their recurrent parents in the major agronomic traits except for panicle length and brown rice 1,000 grain weight. Heading date of NILs ranged from Aug. 10 to Aug. 11, which was similar to that of recurrent parent, Suweon345. Culm length, number of grains per panicle and ratio of ripened grain of NILs were similar to those of Suweon345. Milled rice of NILs was ranged from 4.82 to 4.93MT/ha. These NILs will be useful for improving resistance to K3a race of bacterial blight pathogens in Korean japonica cultivars.

Fusarium head blight (FHB), also known as scab, caused mainly by Fusarium graminearum is a devastating disease of wheat in regions that are warm and humid during flowering. In addition to significant yield and quality losses, the mycotoxin deoxynivalenol produced by the pathogen in infected wheat kernels is a serious problem for food and feed safety. Twenty- three Korean cultivars and "Sumai 3", which is a FHB-resistant Chinese cultivar were tested for Type I, Type II resistances of FHB. Three cultivars were identified as resistant in Type I assessment, and two cultivars were resistant in Type II assessment. Genetic variation and relationship among the cultivars were evaluated on the basis of 11 Simple Sequence Repeat (SSR) and 29 Sequence Tagged Site (STS) markers that were linked to FHB resistance Quantitative Trait Loci (QTL) on chromosome 3BS. One SSR and 7 STS markers detected polymorphisms. Especially, using a STS marker (XSTS3B-57), 32.4% of the variation for Type II FHB resistance could be explained. Genetic relationship among Korean wheat cultivars was generally consistent with their released year. These markers on chromosome 3BS have the potential for accelerating the development of Korean wheat cultivars with improved Fusarium head blight resistance through the use of marker-assisted selection.

야생벼은 재배벼의 친환경적성을 강화시킬 수 있는 병해충 저항성 및 불량환경에 견딜 수 있는 유용한 유전자들의 보고로 알려져 왔다. 국내에서 육성된 벼 품종인 '화성'(AA게놈)와 야생벼인 Oryza. minuta(BBCC 게놈; Acc.=101141)간의 교잡을 통하여 종간잡종 후대들이 육성되었다. 불화합성과 초기분리세대의 극심한 불임을 극복하기 위해 배주배양으로 F1 개체를 확보하였으며, '화성'으로의 여교잡을 수 차례 실시하였다. 확립된 계통들에 대

To investigate dose-effect of a chemical mutagen, sodium azide on a rice elite line, Suweon472, seed aliquots were treated with five different concentrations of sodium azide. The degree of mutation levels of each aizde concentration were estimated by using DNA fingerprinting techniques such as RAPD and AFLP. Some selected mutant lines (M4) were also subjected for DNA fingerprinting to estimate their mutation levels by comparing the banding patterns of the wild type, Suweon 472. RAPD and AFLP fingerprinting patterns indicated that dose-effect of different azide concentrations was not clear. With allele description of detected AFLPs among favorable mutant lines, it was possible to discriminate each mutant line from others which have similar phenotypes and reactions against pathogens. AFLP fingerprinting patterns of waxy mutant lines, otherwise, were highly homogeneous as well as their phenotypic and agronomic characters.

To investigate the mutagenecity of sodium azide (SA) and to select mutants having various agronomic characteristics in rice (Oryza sativa L. ssp. japonica), dry seeds of rice variety 'Suweon 472' were treated with 0, 0.5, 1.0, 2.0, and 4.0 mM SA solutions prepared in 0.1 M phosphate buffer (pH 3.0). Germination rate, seedling height and sterility were investigated in M1 generation and chlorophyll mutations were observed in M3 generation. Germination rate and seedling height decreased as the increase of SA concentration in M1 generation, the maximum seed sterility (40.8%) was found at 4.0 mM SA concentration. Chlorophyll mutants were occurred in M3 generation and the frequency calculated on a line basis was 13.5% at the same treatment. Many kinds of mutations for morphological and agronomic characters were observed and mutations with short culm and glabrous leaf were frequently found in M3 generation. Interestingly, five mutant lines resistant to blast or bacterial blight (BB) were selected and evaluated with several isolates in M3 generation although Suweon 472 has been known to be susceptible to blast and BB. These mutants showed all resistance to seven isolates of blast and a total of 76 lines among 2,567 lines evaluated showed resistant to race K1 of bacterial blight. Two mutant lines (440172 and 41272) showed different reaction to BB isolates from the other resistant mutants. A few kinds of endosperm mutants were also identified and most of them were waxy mutants.

Rice consumption per capta, in South Korea, has been decreased dramatically, owing to the changes of living patterns. Because of not only the major energy source of Korean people but also major income source of Korean farmers, diversifying end-use-quality of rice has been demanded. To the context, 'Suweon 472', a high yielding and early mature japonica line and released as 'Namilbyeo' to framers in 2002, was treated with a chemical mutagen, Sodium Azide to find endosperm mutant types. A total of nine endosperm mutat lines, including five waxy, one dull, two floury, and one white core type, were identified from the 3,542 mutatagen treated lines. Amylose contents, iodine reaction, disintegration in alkali solution, gelatinization in urea solution and amylogram properties of those nine endosperm mutant lines were evaluated to address the possibility as new genetic materials for diversifying rice quality of Korean japonica cultivars. All embryo mutants were clearly differentiated from their wild type, 'Suweon 472', in terms of physic-chemical properties evaluated. The endosperm mutant lines would be very useful in expanding untiliztation of rice through opening new rice markets of processed foods from Korean japonica rice.