본 연구는 벼멸구, 벼흰잎마름병, 벼줄무늬잎마름병에 저항성인 자포니카 복합내병충성 품종을 조기에 확보하고자 약배양을 수행하여 목표 저항성 유전자 조합의 우량 고정계통을 개발하고 육성 과정 중에 발생할 수 있는 문제점을 파악하여 병해충 저항성 육종사업에 반영하고자 수행하였다. 벼흰잎마름병과 벼줄무늬잎마름병에 저항성인 우량 계통 HR26234- 12-1-1과 벼멸구, 벼흰잎마름병, 벼줄무늬잎마름병에 저항성인 SR30071-3-7-23-6-2-1-1을 인공 교배한 F1을 약배양하여 213개 고정계통을 육성하였다. HR26234는 Xa3+xa5, Stvb-i, SR30071은 Bph18, Xa4, Stvb-i를 가지고 있는 것으로 확인되었다. 이들 유래 약배양 계통들은 모두 Stvb-i를 가지고 있었고, Bph18+Xa3, Bph18+Xa4, Bph18+Xa3+xa5, Bph18+Xa4+xa5, bph18+Xa3, bph18+Xa4, bph18+Xa3+ xa5과 bph18+Xa4+xa5의 조합이 확인되었다. 약배양 집단에서 xa5+Bph18(또는 bph18)+Stvb-i 조합이 발생하지 않았고 Bph18 보유 계통이 bph18 보다 적게 발생하는 등 segregation distortion이 발생하였다. Bhp18을 보유하며 벼멸구에 저항성인 계통들이 감수성인 계통들에 비해 간장이 컸다. 선발된 Bph18+Xa4+xa5+Stvb-i 조합의 계통은 단간이면서 벼멸구, 벼흰잎마름병, 벼줄무늬잎마름병에 저항성을 나타내었으나, 낮은 수량성과 일부 불임의 발생, 단간임에도 도복에 안정적이지 못한 특성을 나타냈다. 병해충에 대한 저항성 육종사업에서 약배양을 활용하여 조기에 육종 목표를 달성하고자 할 경우에 segregation distortion이 발생하여 편의 된 변이가 발생할 수 있고, 저항성 유전자 도입 시 linkage drag에 의해 예기치 못한 열악형질 특성이 나타날 수 있음을 고려하여 신중하게 목표에 접근하여야 할 것으로 생각한다.

쌀 가공산업을 활성화하고 소비를 촉진하여 국내 쌀 생산기반을 유지하기 위해서는 쌀가루 제분적성을 보유한 가공용벼 품종 개발이 시급하다. 농촌진흥청 국립식량과학원에서는 아지드화나트륨을 돌연변이원으로 활용하여 건식제분적합성을 보유한 분질배유 돌연변이 후대계통인 ‘Namil(SA)-flo1’를 육성한 바 있다. 본 연구는 염색체 상에서 ‘Namil(SA)-flo1’의 분질배유 특성을 지배하는 유전자위를 탐색하고자수행하였다. 주요 결과는 아래와 같다.1. ‘Namil(SA)-flo1’ × ‘밀양23호’로부터 유래한 F2 94 개체로부터 종자 분질립 비율을 검정하고 54개 SSR 마커의 유전자형을 검정하여 연관성분석(association analysis)을 수행한 결과 목표 유전자위는 5번 염색체 중하단부위로 추정되었다.2. 목표 부위의 SSR 마커 밀도를 높여 추가 연관성분석을 실시하였고, F2:3 종자 분질립 변이의 79.7%가 5번염색체 상의 RM164의 유전자형 변이에 의하여 설명된다는 것을 확인하였다.3. 이를 통하여 분질배유 지배 유전자위를 5번 염색체17.7~20.7 Mbp 부위로 추정하였으며, 추후 추가 분리집단을 이용하여 목표 유전자를 동정하고 쌀가루용품종 개발에 활용할 수 있는 핵산정밀표지인자를 개발할 계획이다.

아밀로스 함량차이에 따른 배유전분의 이화학적 특성을 파악하기 위해 아밀로스 함량의 차이를 보이는 찰벼, 저 아밀로스, 중간 아밀로스, 고 아밀로스 품종의 외관특성, 화학특성, 호화특성 및 기계적 식미치를 조사하였으며, 그 결과를 요약하면 다음과 같다.1. 시료들의 아밀로스 함량은 6.3%∼30.9% 범위로 아밀로스 함량차이에 따라 4개 그룹 찰벼(A), 저 아밀로스(B), 중간 아밀로스(C), 고 아밀로스(D) 품종군으로 나눌 수 있었으며 각 그룹에 속한 품종들의 단백질함량은 5.8 ~ 7.5%로 품종간 차이가 있었으나 아밀로스 함량에 따라 분류된 그룹간 차이는 없었다.2. 시험재료의 외형적 특성을 보면, 백도는 찰벼 품종군이 가장 높고 저아밀 중간아밀로스 품종군이 가장 낮았다. 현미경도는 고 아밀로스 품종 및 찰벼 품종이 메벼품종과 저 아밀로스 품종보다 대체적으로 낮았다.알카리 붕괴도는 5.2∼6.9의 분포를 보였으며 아밀로스 함량이 증가할수록 붕괴도가 커졌으며, 아밀로스 함량과 알카리 붕괴도 간 매우 높은 양의 상관(r=0.884**)을 보였다.3. 아밀로그램 특성을 살펴보면 저 아밀로스 품종군은 호화개시온도가 중간 아밀로스 품종과 비슷한 반면 최고점도와 강화점도는 높고 최종점도와 치반점도는 낮았다. 고 아밀로스 품종군은 호화개시온도가 다른 품종군에 비해 높고, 최고점도와 최저점도가 매우 낮았으며 최종점도가 상대적으로 높아서 강하점도는 낮고 치반점도는 높은 특성을 보였다.4. 식미관련 이화학적 특성들 간 상관을 살펴보면 아밀로스함량은 알카리 붕괴도와 상당히 높은 양의 상관(r=0.88**)을 Toyo-윤기치와는 높은 음의 상관(r=-0.89**) 나타냈고, 아밀로그램 특성 중에서는 호화개시온도, 치반점도와 유의한 양의 상관을 보이며, 강하점도와는 음의 상관을 나타냈다.

The transfer of a biotic resistance gene from indica rice cultivars into japonica cultivars by conventional breeding methods often difficult due to high sterility of the progenies, poor plant type, and linkage drag. Molecular markers provide opportunities to map resistance genes and accelerate the application of marker-assisted backcross(MAB) breeding through the precise transfer of target genomic regions into the recurrent parent. The basis of MAB breeding is to transfer a specific gene/allele of the donor parent into the recurrent parent genome while selecting against donor introgressions across the rest of the genome. The effectiveness of MAB breeding depends on the availability of closely linked DNA markers for the target locus, the size of the population, the number of backcrosses and the position and number of markers for background selection. We have successfully developed Bph18 version of the commercially cultivated japonica elite cultivar by using MAB and incorporating the resistance gene Bph18 that conferred enhanced resistance to BPH. MAB breeding provides a new opportunity for the selective transfer of biotic resistance genes into elite indica rice cultivars devoid of linkage drag. In additon, molecular markers precisely estimate the introgression of chromosome segments from donor parents and can speed up the recipient genome recovery via background selection.

국내 대학과 국립식량과학원 간의 협력 연구를 통해 확보된 32개 벼 형질전환 계통들 중 작물학적 성능이 유망한 11개 계통들에 대해 작물학적 특성과 미질 특성이 평가되었다. 주요 결과는 아래와 같다.1. 이들 계통들은 수량성, 환경스트레스저항성, 내병성에관여하는 7종의 유전자가 니폰바레, 낙동벼, 동진벼등에 형질전환 되어 육성된 계통들이다.2. 미질 특성과 관련된 11개 조사형질을 이용한 다변량분석결과, 형질전환에 이용된 모품종과 도입유전자들에 대한 각 형질전환 계통군들의 뚜렷한 집구현상은관찰되지 않았다.3. 실용적 측면에서는 작물학적 특성이 모품종과 유사하면서 미질 특성이 양호한 계통이 다수 확인되었다.4. 그러나 모품종의 유용한 작물학적 특성, 즉 ‘상품성’을온전히 견지하고 있다고 판단되는 계통은 선정하기 어려웠다.5. 도입할 유전자의 선정과 유전적으로 고정된 형질전환계통을 확보하는데 소요되는 경비와 시간을 고려할때, 향후 우량 벼 형질전환 계통의 육성효율을 제고하기 위해서는 기존에 비해 보다 구체적이며 차별화 된육종전략의 개발이 필요하다고 판단되었다.

국내 대학과 국립식량과학원 간의 협력 연구를 통해 확보된 32개 벼 형질전환 계통들에 대하여 주요 작물학적 특성및 수량성을 평가하였다. 이들 계통들은 수량성, 내병성, 스트레스저항성, 미질변이 등에 관여하는 17종의 유전자가 니폰바레, 낙동벼, 동진벼 등에 형질전환 되어 육성된 계통들이다. 주요 결과는 아래와 같다.1. 형질전환 계통들은 출수기, 간장, 수장, 수수 등의 주요작물학적 특성뿐만 아니라 수량성에서도 모품종과 상당한 차이를 보였다.2. 조사된 벼 형질 전환계통들에서 조사된 농업형질에 대한다변량분석 결과, 모품종에 비해 각 형질전환 계통군 내에서 관찰된 작물학적 상이성은 일정한 방향성이 없는무작위적이었으며, 그 변화폭도 3개의 모품종들의 작물학적 차이보다 훨씬 크게 관찰되었다.3. 따라서 우량 벼 형질전환 계통 육성의 효율성을 제고하기 위해서는 모품종에 형질전환 되어 발현될 유전자의우수성뿐만 아니라, 계통육성과정에서 다양한 유전학적요인에 의해 야기되는 ‘표현형 왜곡현상’을 적절히 제어할 수 있는 육종전략도 함께 고려되어야 할 것으로 사료되었다.

The use of functional markers, it is expected to make direct identification about genetic diversity at DNA level and overcome the problem of recombination /linkage. These markers can be used to identify interesting alleles in a breeding program and indirectly select for the trait, saving money, time and labor. Bacterial blight of rice caused by Xanthomonas oryzaepv. Oryzae is a destructive disease in rice production worldwide. No bactericide is effective to control the bacterial blight disease yet. Xa3, which is a gene conferring resistance to BB of the rice plant has been previously characterized by map-based cloning. We have cloned and sequenced the Xa3/xa3 gene in Korean cultivar, Hwayoung, Ilmi and Goun with gene specific primers. Our work detected polymorphisms and PCR-based allele specific SNP markers were developed. Susceptible or resistant individuals from an F2 population developed from across between Milyang244 and Ilmi, Korean germplasms and near isogenic lines carrying BB resistance genes were screened with allele specific markers. We found that the genotype completely matched their phenotype to BB using ASP-primers. These markers could be effective to marker-assisted selection for the Xa3 gene in rice breeding programs.

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.

Protein related parameters of pan bread and white salted noodles prepared from 26 Korean wheat cultivars and 6 commercial and imported wheat flours were evaluated to elucidate the relationship between rheological properties and end-use characteristics and to determine the effects of Glu-1 and Glu-3 alleles on those characteristics in Korean wheat cultivars. SDS-sedimentation volume based on protein weight was positively correlated with mixograph parameters and maximum height of dough and also positively correlated with bread loaf volume, crumb firmness and springiness of cooked noodles. Within Glu-1 loci, 1 or 2* subunit and 5 + 10 subunits showed longer mixingtime, higher maximum height of dough, and larger loaf volume than null allele, 2.2 + 12, and 2 + 12 subunits. Cultivars with 13 + 16 subunits at Glu-B1 locus showed higher protein content and optimum water absorption of mixograph than cultivars with 7 + 8 subunits. At Glu-3 loci, Glu-A3d showed longer mixing time than Glu-A3e, and Glu-B3d and Glu-B3h had stronger mixing properties than Glu-B3i. Glu-B3h had higher loaf volume and hardness of cooked noodles than Glu-B3d. Glu-D3a had lower protein content than Glu-D3c, and Glu-D3b showed stronger mixing properties than Glu-D3a. Glu-D3c showed lower hardness of cooked noodles than others.

Allelic variations in glutenin and puroindolines of Korean wheat cultivars evaluated to determine the effects of allelic variations on physico-chemical properties of flour and qualities of white salted noodles. In grain hardness and flour yield, Pinb-D1b had higher hardness index and flour yield than Pinb-D1a alleles. Glu-B1b and Glu-D1f also had lower hardness index than other alleles at the same locus and Glu-A1c, Glu-A3e and Glu-B3i alleles showed lower flour yield than other alleles. In flour compositions, Pina-D1b and Pinb-D1b showed higher particle size, ash and damaged starch content and lower lightness of wheat flour than Pina-D1a and Pinb-D1a. Glu-A1c, Glu-B1b, Glu-D1f, Glu-B3d and Glu-B3i showed lower particle size of flour than other alleles at Glu-1 and Glu-B3 locus. Korean wheats with Glu-B1f, Glu-D1a and Glu-B3b alleles had higher damaged starch content and lower lightness of flour than wheats other alleles at the same locus. Glu-B1b, Glu-D1f, Glu-B3d and Pina-D1a showed lower protein content and Glu-A1c, Glu-B1b, Glu-D1f Glu-B3d, Glu-B3i and Pinb-D1b showed lower SDS-sedimentation volume than other alleles. Hardness of cooked noodles ranked as Glu-A1a > Glu-A1c > Glu-A1c at Glu-A1 locus. Glu-B3h showed higher hardness of cooked noodles (5.10 N) than other alleles at Glu-B3 locus (< 4.66 N).

Fusarium head blight (FHB) is the most important disease of wheat that may cause serious yield and quality losses and leads to harmful contamination of the grain with fungal toxins. Korean wheat cultivars showed much less resistant to FHB than Sumai3, which known as resistance to FHB, evaluated by spray inoculation in our companion report. Many DNA-marker studies, including sequence tagged site (STS) and simple sequence repeat (SSR) markers and qualitative trait loci (QTL) associated with FHB resistance have been identified and mapped on the specific chromosome, especially 3BS, by many previous studies. However, there was no application of DNA-markers to select FHB resistance lines in Korean wheat breeding programs. 3 SSR markers and 6 STS markers linked to major QTL on chromosome arms 3BS found in Sumai3 and its derivatives were used to screen FHB resistance in Korean wheat cultivars. All markers known to be most significant markers based on previous research (Liu and Anderson 2003). There was general lack of marker polymorphism for Korean wheat cultivars used in this study. However, STS3B-138 marker only showed the polymorphism in Korean wheat cultivars. Allele size of STS3B-138 is 355 bp in Sumai 3 and 12 of 24 cultivar showed this allele. The range in Type II resistance rating was 1-5 and average of these 12 cultivars have 355bp allele was grade 2.4. The most resistant cultivars under the 2 grade, Gobun, Jinpoom, Milseong and Namhae also showed 355bp allele. Therefore, These results provide potential for development of wheat cultivars with improved Fusarium head blight resistance through use of effective FHB screen methods and marker - assisted selection.

Fusarium head blight (FHB), also known as head scab of wheat causes serious yield losses and deteriorated grain and may also contaminate the grain with mycotoxins. Many researches have been conducted to minimize damage caused by FHB and to improve resistance to FHB in many countries. However, little information of FHB in Korean wheats is available. In this study, 23 Korean wheat cultivars and F8 population were evaluated FHB symptoms infected two types of inoculations, both spray and point inoculation. Grain properties of Korean wheat cultivars, including grain morphology, antioxidant activity and ion content, were also evaluated to elucidated the relationship to the degree of infection of FHB. Anbaek, Eunpa and Milsung showed lower degree of infection by spray inoculation than any other cultivars, in spite of higher infection degree than Sumai3, which have been known as resistant to FHB. The degree of infection by point inoculation of Milsung, Gobun and Olgeuru was comparable to that of Sumai3. Poly phenol oxidase activity and total polyphenol content negatively correlated with the degree of infection by spray inoculation (r = -0.388, r = -0.466* respectively). Roundness of grain positively correlated with the degree of infection by point inoculation (r = 0.419*). In F8 population of 234 lines derived from the cross between Sumai3 and Korean wheat cultivar, 33 lines (14.1%) showed lower degree of infection by spray inoculation than parental cultivars, although there was no line comparable resistance of FHB to Sumai3. Fourteen lines (6.0%) showed lower degree of infection by point inoculation than Sumai3 and 135 lines (57.6%) were comparable to Sumai3 and parental cultivars.

Brown planthopper (BPH) is a major insect pest of tropical indica and temperate japonica rice in Asia and Africa. A major BPH resistance gene, Bph18 derived from IR65482-7-216-1-2 has been fine mapped on chromosome 12 and confers strong resistance to the Korean biotype of BPH. The Bph18 gene is tightly linked to the STS marker, 7312.T4A and is non-allelic to previously reported resistance genes present on chromosome 12. The Bph18 gene has been transferred into two elite japonica cultivars (Jinbubyeo and Junambyeo) background through marker-assisted backcross breeding (MAB) strategy. Foreground selection using STS markrs linked to the Bph18 gene in advanced backcross progenies confirmed homozygous marker alleles associated with BPH resistance. Background selection of the breeding lines with 260 simple repeat (SSR) markers revealed rapid conversion toward recurrent parent genotypes with less donor chromosomal segments (5.3-16.7%). Major agronomic traits of the progenies were analyzed and some breeding lines have agronomic traits comparable to the recurrent parent. One breeding line (S.523) with multiple-resistance to BPH and major diseases, desirable agronomic traits and grain quality has been recommended for regional testing in Korea. MAB is the suitable strategy to incorporate new genes into susceptible japonica to develop elite breeding lines.

ABSTRACT: Wide hybridization was used to broaden the gene pool of japonica rice. Different approaches involving direct crosses between four japonica cultivars and eight wild species in combination with anther culture, embryo rescue, and molecular markers were used to produce interspecific hybrids, advanced alien introgression lines, dihaploids, and characterization of alien introgression. Interspecific hybrids were produced between Jinmibyeo, Ilpumbyeo, and Hwaseongbyeo cultivars of rice (O. sativa, 2n=24 AA) and wild species, O. rufipogon (2n=24, AA), O. longistaminata (2n=24, AA), O. punctata (2n=24, BB), O. minuta (2n=48, BBCC), O. alta (2n=24, CCDD), including African rice species, O. glaberrima (2n=24, AA). Crosses involving species other than A genome were produced through embryo rescue and were sterile. Following backcrossing with the recurrent japonica parents, advanced progenies have been produced for transfer of alien genes into japonica rice. As results of yield trials, three elite lines were generated from this cross; they are "Suweon 487" with resistance to black streak dwarf virus, "Suweon 497" with blast and bacterial blight resistance and "Suweon 506" with blast resistance, emonstrating that wild species genes have now become important component of japonica rice breeding.