‘큰눈’은 다양한 전분 신소재를 육성할 목적으로 1991년 하계에 양질다수성 품종인 ‘일품벼’에 돌연변이처리(MNU)하여 중만생이며 배가 일반벼보다 큰 거대배아미인 ‘Ilpum MNU)36-2-GH1-2-10-1-2-3-2-1’ 계통을 선발하여 ‘수원492호’로 계통명을 부여하여, 2003년부터 2005년까지 3년간 지역적응시험 실시결과 그 우수성이 인정되어 2005년 12월 직무육성 신품종 선정위원회에서 국가목록등재 품종으로 선정됨과 동시에 ‘큰눈’으로 명명하였다. ‘큰눈’의 중부평야지의 평균 출수기는 8월 17일로 ‘화성벼’보다 6일 느리고, 남부평야지 평균 출수기는 8월 15일로 ‘남평벼’보다 1일 빠른 중생종이다. ‘큰눈’의 간장은 86 cm이며, 이삭길이는 23 cm로 ‘화성벼’와 비슷하고, 포기당 이삭수는 ‘화성벼’보다 적으나, 수당립수는 많고, 등숙비율은 낮은 편이며, 현미 천립중은 가벼운 편이다. ‘큰눈’은 도열병 저항성은 약한 반응을 보였으며, 흰잎마름병 및 바이러스병과 벼멸구 및 애멸구 저항성은 없었다. ‘큰눈’은 내냉성검정에서 ‘화성벼’에 비해 출수지연일수가 다소 길고, 냉수구 임실율이 낮아서 내냉성은 약한 편이며, 도복특성검정에서 좌절중은 낮고, 도복지수는 높은 편이나 포장 도복은 강한 편이다. ‘큰눈’은 현미장폭비가 1.62인 중단원립이고, 투명도가 다소 불량하고 심복백이 많아 외관 품위가 떨어지고, 아밀로스와 단백질 함량은 각각 17.5, 5.9%로 ‘화성벼’보다 낮은 편이며, 단당류 및 올리고당 함량은 ‘화성벼’보다 1.4배, 발아현미의 GABA 함량은 발아 2일에서 ‘일품벼’보다 2.8배 많았다. ‘큰눈’의 쌀수량은 보통기재배에서 평균 쌀수량이 4.52 MT/ha로 ‘화성벼’ 대비 89% 수준이었다. ‘큰눈’의 재배적지는 중부평야 및 남부평야지이다.

Eating quality is critical for consumers who take rice as staple food. Here we present the development and identification of high eating quality rice lines. The identification of positive transgenic lines, physicochemical properties of transgenic rice, mRNA expression and enzyme activity were analyzed. OsSbe1 was introduced into Gopumbyeo seeds using Agrobacterium-mediated transformation, and 1,005 out of 1,065 T1 plants were shown positive. The apparent amylose contents in T2 brown rice ranged from 11% to 25% in 890 favorable lines (Gopumbyeo was used as a reference with 18% of AAC). The activity of starch branching enzyme including three isoforms (SBE1, SBE3, and SBE4) in endosperms of T3 lines was higher than that of Gopumbyeo. Physicochemical properties related to eating quality for T3 polished rice were detected using 52 favorable lines out of 500 lines selected according to AAC. The Toyo taste meter value in 52 T3 lines ranged from 61.1 to 72.6, whereas 70.4 in Gopumbyeo. Of them, eleven lines displayed the higher palatability score than Gopumbyeo. Moreover, these elite lines produced higher yields (607.9~695.8 kg/10a) than Gopumbyeo (602.7 kg/10a). These results indicated the possibility of developing new high quality rice varieties in the future.

Blast resistance of one hundred and thirty-one rice cultivars bred in Korea was tested with thirty Korean isolates and twenty-two Philippines isolates using three screening methods. In the blast nursery conducted in Korea and in the Philippines, average disease index of rice cultivars were 4.6 and 2.2, respectively. Seventy-nine cultivars showed different resistance reaction in Korea and in the Philippines, and 19 cultivars showed the same resistant reaction in two locations. In the seedling test, Korean blast isolates displayed different levels of virulence. 93-093, a Korean isolate, was compatible with 90 cultivars whereas 97-057 showed a compatible reaction with 13 cultivars. Twenty-three cultivars showed high level of resistance against Korean and Philippines isolates but Chucheongbyeo, Heugnambyeo, and Manmibyeo showed susceptible reaction to all blast isolates. Through the sequential planting test in Korea and in the Philippines, Palgongbyeo and Seomjinbyeo displayed durable resistance, and Nagdongbyeo and Gihobyeo showed high level of disease infection over the planting time. These results indicate that blast isolates collected in two countries have different genetic background and number of compatible isolates should be considered in definition the durability of rice cultivar to rice blast.

Field resistance is defined as the resistance that allows effective control of a parasite under natural field condition and is durable when exposed to new races of that parasite. To identify the genes for field resistance against rice blast, quantitative trait loci (QTLs) conferring field resistance in japonica rice cultivars were detected and mapped using SSR markers. QTL analysis was carried out in 190 RILs population from the cross between Suweon365 (moderately resistance) and Chucheong (highly susceptible). Fourteen QTLs for nine blast races inoculated were detected on chromosomes 1, 2, 4, 5, 6, 7, 11 and 12. They explained from 6.4 to 39.7% of total phenotypic variation. Eight QTLs for blast nursery screening in 4 regions for three years were detected on chromosomes 1, 2, 4, 5, 11 and 12. The phenotypic variation was explained by each QTL ranged from 5.9 to 38.0%. Three BC2F5 backcrossed progeny lines were developed to transfer the QTLs into the susceptible cultivar Chucheong as a recurrent parent. A NIL4 containing two QTLs Qbl6.2 and Qbl7 for blast races showed the reaction 6 to 7 in blast nursery in 2007 and 2008, respectively. Two lines NIL143 and NIL93 containing Qbl11.2 and Qbl12.1 for QTLs related with field resistance, respectively, were 3 to 4 reactions in blast nursery.

Fifty-two Korean japonica rice cultivars were analyzed for leaf blast resistance and genotyped with 4 STS and 26 SSR markers flanking the specific chromosome sites linked with blast resistance genes. In our analysis of resistance genes in 52 japonica cultivars using STS markers tightly linked to Pib, Pita, Pi5(t) and Pi9(t), the blast nursery reaction of the cultivars possessing the each four major genes were not identical to that of the differential lines. Eight of the 26 SSR markers were associated with resistant phenotypes against the isolates of blast nursery as well as the specific Korean blast isolates, 90-008 (KI-1113), 03-177 (KJ-105). These markers were linked to Pit, Pish, Pib, Pi5(t), Piz, Pia, Pik, Pi18, Pita and Pi25(t) resistance gene loci. Three of the eight SSR markers, MRG5836, RM224 and RM7102 only showed significantly associated with the phenotypes of blast nursery test for two consecutive years. These three SSR markers also could distinguish between resistant and susceptible japonica cultivars. These results demonstrate the usefulness of marker-assisted selection and genotypic monitoring for blast resistance of rice in blast breeding programs.

This experiment was conducted to evaluate genetic variation in 48 rice accessions (Oryza sativa L.) using AFLP and RAPD markers. For AFLP, a total of 928 bands were generated with 11 primer combinations and 327 bands (35.2%) of them were polymorphic among 48 accessions. In RAPD analyses using 22 random primers 145 bands were produced, and 121 (83.4%) were polymorphic among 48 accessions. Each accession revealed a distinct fingerprint by two DNA marker systems. Cluster analysis using AFLP-based genetic similarity tended to classify rice cultivars into different groups corresponding to their varietal types and breeding pedigrees, but not using RAPD-based genetic similarity. The AFLP marker system was more sensitive than RAPD in fingerprinting of rice cultivars with narrow genetic diversity.