일품벼 유래 돌연변이 고아밀로스 품종인 고아미2호, 고아 미3호, 고아미4호의 저항전분 함량과 전분 특성을 분석한 결 과, 저항전분 함량은 11.87～13.69%로 일품(0.36%)에 비해 상당히 높은 유의적인 함량 차이를 나타냈다. 총식이섬유 함 량 역시 고아밀로스 품종이 일품벼 대비 2～4배 정도로 높았 다. X-선 회절도에 의한 아밀로펙틴 결정 구조 차이에서 일품 의 회절각도(2θ)는 15.0, 17～18, 22～23에서 강한 피크를 보여 전형적인 A형 양상을 보인 반면, 고아미2호, 고아미3호, 고아미4호는 B형의 형태를 나타냈다. 고아밀로스 품종은 아 밀로펙틴 짧은 사슬(A, DP 6-12) 비율이 24.5～26.2%로 일 품(40.3%)에 비해 유의적으로 낮은 분포 비율을 나타냈다. 저항전분 함량이 많은 고아미2호, 고아미3호, 고아미4호는 신 속점도계에 의한 호화 점도 특성에서 호화개시온도가 높고 강하점도는 유의적으로 낮은 특성을 보였다. 저항전분과 쌀의 이화학성분 특성과의 상관성 분석 결과, 쌀의 아밀로스 함량 과 식이섬유 함량이 많을수록, 호화개시온도가 높을수록, 아밀로펙틴의 장쇄사슬이 많을수록 저항전분의 함량이 높아지 는 정의 상관성을 나타냈다.

Narrow genetic diversity of Korean commercial rice lines have been a major limit factor in breeding new breeding lines having resistance and tolerance against biotic and abiotic stresses. Introducing novel favorable allele types could be possible through crossing with wild relatives, it demands additional tedious efforts to restore the unique genetic background of the recurrent parents, which determine commercial value in the market. Our study is preliminary based on the mutation breeding, by which agronomic traits could be acquired with the least impact on the unique haplotype of the wild type. Through screening and evaluating more than 7,000 mutant lines of Namil, a high yielding Korean japonica cultivar, several dozens of mutant lines expressing improved performances in terms of resistance or tolerance against biotic or abiotic stresses. One Sodium azide treated mutant line, Namil(SA)M2-1063-11-1-1-1-1-1-1, designated as ‘Namil(SA)-bl5’ performed high level of resistance against rice blast as well as reduced culm length. Two mapping populations, to dissect genetic basis of the blast resistance and short culm length, were constructed by using F2 progenies derives crosses between Namil(SA)-bl5 and Milyang23 and Namil(wild type) and Milyang23. Each progenies were evaluated in terms of DNA marker genotype as well as basal agronomic traits including blast resistance by using F2:3 seeds. Association analysis between marker genotype and evaluated phenotype of progeny lines were adopted to localize the putative chromosomal locations involved to culm length and blast resistance. The putative locations unique to Namil(SA)-bl5 were then elucidated through the comparisons with those of Namil x Milyang23 reference population. Tentatively, the genetic factors for reduced culm length and blast resistance were identified on chromosome 7 and chromosome 12, respectively.

Brown planthopper (BPH) is a destructive insect pest of rice in Korea. Identification and the incorporation of newBPH resistance genes into modern rice cultivars are important breeding strategies to control the damage caused by BPH. To expand genetic resource against BPH in Korea, we screened more than 2,500 mutant lines, which were derived from EMS treatment on Namil, a high yielding Korean japonica cultivar. One mutant line, Namil(EMS)M2-1463-1-1-1-1, designated as ‘Namil(EMS)-bl10,bph1’ performed high level of resistance against BPGH and rice blast, while the wild type, Namil, performed highly susceptible to rice blast as well as BPH. A mapping population was constructed by using F2 progeny lines derived from cross between Namil(EMS)-bl10,bph1 and Milyang23, a BPH susceptible Tongil type cultivar. DNAs prepared from F2 individuals were used for SSR marker based linkage map skeleton, and F2:3 seeds were subjected to BPH infestation to infer resistance level of corresponding F2 plant. Association analysis between marker genotype and evaluated survival ratio of each progeny line were used to localize the putative chromosomal location(s) involved to BPH resistance. The location was initially located on the subterminal region of the long arm of chromosome 12 flanked by the SSR markers RM1337 and RM277, where at least three BPH resistance genes, Bph1, Bph18, and Bph21, were localized previously.

Rehmannia glutinosa is one of the most important medicinal crops in Korea. However, various plant pathogens including Fusarium sp. cause great damages and cause enormous economic losses. Therefore, this study was conducted to select Fusarium resistant plants by using mutagen-treated Rehmannia glutinosa. The plant material used was a native accession of Rehmannia glutinosa. As a result, among the Rehmannia glutinosa treated with various concentrations of EMS, R. glutinosa treated with 0. 03M EMS showed higher resistance against infection of F. oxysporum in pot tests, and Rehmannia glutinosa plants treated with 0.12M EMS showed higher resistance against infection of F. oxysporum in field tests.

옥수수의 5-methyltryptophan 저 항성 돌연변이 주（MR1）로부터 anthranilate synthetase（AS）와 tryptophan synthetase（75）의 특성을 분석하였다. 대조구 식물로써 사용한 옥수수 품종 당진의 순계와 저항성주에 있어서 AS와 75의 효소 활성은 5-MT를 포함하지 않은 MS기본배지에서 생장시켰을 때는 차이를 보이지 않았다. 그러나, 25mg/L의 5-MT를 포함한 MS배지에서 생장한 MR1에 있어서 AS의 활성은 대조구보다 2배 높았다. 또한, 4mg/L의 L-tryptophan을 처리 했을때의 AS의 활성은 50％ 저해 되었다. MR1의 조추출물로부터 대조구와 동일한 활성저해율을 나타내기 위해서는 약 4배의 아미노산이 필요하였다. MR1의 75활성은 대조 식물보다 4배가 더 높았다. 그리 하여 tryptophan synthetase B subunit （TSB）를 encoding하는 유전자를 cloning하여 염기배열을 결정 하였다. TSB유전자는 상이한 기관으로부터 cloning된 TSB와 높은 상동성을 보였으며, 모든 발육단계에서 발현하였다. 띠orthern hybridization분석에서 MR1의 TSB발현량은 대조식물보다 높게 나타났다