‘안미’는 농촌진흥청 국립식량과학원과 국제미작연구소 간의 협력으로 분자육종법을 이용하여 2010년에 육성한 중만생 고품질 복합내병충성 품종이다. 지역적응시험을 3개년(2008~2010)간 수행한 결과, ‘안미’는 중부평야지에서 보통기 보비재배 시 출수기는 8월 15일로 ‘화성’보다 5일 늦은 중만생종으로 쌀수량은 보통기 표준재배에서 5.76 MT/ha로 ‘화성’보다 11% 증수되었다. ‘안미’는 ‘화성’에 비해 간장(77 cm)은 작고 수당립수는 많으나 등숙비율은 다소 낮았다. ‘안미’는 현미 장폭비가 1.84인 단원형이며 백미는 심복백 발현이 거의 없어 맑고 투명하다. ‘안미’의 알카리 붕괴도와 단백질 함량은 ‘화성’과 비슷하고 아밀로스 함량은 조금 낮았반면, 식미평가에서 밥맛은 매우 양호하였다. ‘안미’의 재배시험 과정 중 위조현상은 관찰되지 않았으며 성숙기 하위엽 노화는 늦은 편이었다. ‘안미’는 ‘화성’에 비해 수발아에 둔감하였고 내랭성 평가 중 적고는 나타나지 않았으나 임실율은 다소 낮았다. ‘안미’는 도열병, 벼흰잎마름병(K₁, K₂, K₃), 줄무늬잎마름병 및 벼멸구에 강한 저항성을 발현하였다.

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.

Cold stress at the seedling stage is a major threat to rice production. Cold tolerance is controlled by complex genetic factors. We used an F7 recombinant inbred line (RIL) population of 123 individuals derived from the cross of a cold-tolerant japonica and a cold-sensitive indica cultivars, for QTL mapping. Phenotypic evaluation of the parents and RILs in an 18/8oC (day/night) cold-stress regime showed continuous variations for cold tolerance or sensitivity. Six QTLs for seedling cold tolerance were identified on chromosomes 1, 2, 4, 10, and 11 with percent phenotypic variation (R2) ranging from 6.1% to 16.5%. Three main-effect QTLs (qSCT1, qSCT4, and qSCT11) were detected in all cold-tolerant RILs which explained high sum of phenotypic variation (SPV) ranging from 27.1% to 50.6%. Two QTLs (qSCT1 and qSCT11) on chromosomes 1 and 11 were fine mapped. The marker In1-c3 from ORF LOC_Os01g69910 of the BAC clone B1455F06 encoding calmodulin-binding transcription activator (CAMTA) and another marker, In11-d1 from ORF LOC_Os11g37720 (Duf6 gene) of the BAC clone OSJNBa0029K08, co-segregated with seedling cold tolerance. These two InDel markers amplified 241-bp and 158-bp alleles, respectively, in cold-tolerant RILs, and in the cold-tolerant donor Jinbu, which were absent in cold-sensitive parent BR29 and cold-sensitive RILs.

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.

Ilpumbyeo, a japonica rice cultivar which is known to have premium eating-quality, and high yield potential, but susceptible to rice blast disease was studied whether it has any specific rice blast resistance gene/QTL. Using CAPS markers which were develo

The production and productivity of major crop plants have reached their plateu during the past decade because of adop-tion of green revolution technologies. However, further increase in production of cereals with improved cereal quality is imperativeto fe