Advances in plant molecular techniques have dramatically widened the applicability of gene identification and pyramiding valuable genes. This study was carried out to pyramid five resistance genes for biotic stress into the japonica rice cultivar using marker-assisted selection (MAS) and marker-assisted background analysis of selected progenies using SSR markers. The Pi40, Xa4, xa5, Xa21 and Bph18 genes were combined in Jinbubyeo, a Korean japonica rice variety using MAS. Gene specific co-dominant PCR-based markers were used to select for homozygous recombinant lines in a segregating population derived from a cross between the parental homozygous resistant gene introgression lines. We had successfully developed multiple gene pyramided breeding lines (GPLs) for bacterial blight, blast, and brown planthopper using MAS in rice. The GPLs exhibited high resistance against biotic stress and had around 93% of the genetic background of the recurrent parent Jinbubyeo based on SSR graphical mapping. The yield and agronomic traits of the GPLs were similar to those of the recurrent parent, indicating that there is no apparent agronomic trait penalty associated with the presence of the resistance genes. The strategy of simultaneous foreground and phenotypic selection to introduce multiple R genes is very useful to reduce the cost and the time required for the isolation of desirable recombinants with target resistance genes in rice. The GPLs could be useful to enhance effective resistance for biotic stress and produce stable grain yield in japonica rice breeding programs.

Wild relatives of rice in the genus Oryza (composed of 24 species with 11 different genome types) have been significantly contributing to the varietal improvement of rice (Oryza sativa). More than 4000 accessions of wild rice species are available and they are regarded as a “genetic reservoir” for further rice improvement. DNA markers are essential tools in genetic analysis and breeding. To date, genome-wide marker sets for wild rice species have not been well established and this is one of the major difficulties for the efficient use of wild germplasm. Here, we developed 541 genome-wide InDel markers for the discrimination of alleles between the cultivated species O. sativa and the other seven AA-genome species by positional multiple sequence alignments among five AA-genome species with four rice varieties. The newly developed markers were tested by PCR-agarose gel analysis of 24 accessions from eight AA genome species (three accessions per species) along with two representative cultivars (O. sativa subsp. indica cv. IR24 and subsp. japonica cv. Nipponbare). Marker polymorphism was validated for 475 markers. The number of polymorphic markers between IR24 and each species (three accessions) ranged from 338 (versus O. rufipogon) to 416 (versus O. longistaminata) and the values in comparison with Nipponbare ranged from 179 (versus O. glaberrima) to 323 (versus O. glumaepatula). These marker sets will be useful for genetic studies and use of the AA-genome wild rice species.

The 'Hangaru' is a rice variety derived from a cross between 'Seolgaeng', which is suitable for making rice wine, and 'Daeripbyeo1', which has a heavy grain weight (34.8g) and is suitable for deep fried rice, by the rice breeding team at the National Institute of Crop Science, Rural Development Administration, in 2017. The heading date of 'Hangaru' was August 18 and was 10 days later than check variety, 'Hwaseong', in Suwon. It had a culm length of 79 cm and 102 spikelets per panicle, and showed similar tolerance to 'Hwaseong' when exposed to cold stress. 'Hangaru' showed medium resistance to blast disease, but susceptibility to bacterial blight, viruses and brown planthoppers. The milled rice of this variety exhibited an opaque and non-glutinous endosperm. The 1,000 grain weight of brown rice was 32.9 g, which was 10.8 g heavier than that of 'Hwaseong'; the protein content was 7.0% and the amylose content (19.2%) was similar to that of 'Hwaseong'. The milled rice recovery rate was lower than that of 'Hwaseong'. However, opaque grain percentage of milled rice was 88.1%. The hardness of the rice grain was soft and the starch granule shape in the endosperm was round, similar to wheat. The average size of rice flour was 71.0 µm and the damaged starch rate was 6.4%. These results showed that this variety could be suitable for dry milling rice flour production. 'Hangaru' had a yield of 5.42 MT/ha of milled rice productivity in ordinary cultivation, which was 99% of that of 'Hwaseong'. 'Hangaru' was adaptable to the middle plain area and Mid-west coast of Korea (Registration No. 7270). This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 서 언 최근 서구화된 식생활 변화 및 간편식을 선호하는 소비 양상의 변화로 쌀 소비량은 지속적인 감소를 보여 2018년 연간 1인당 쌀소비량은 61.0 kg이었고(KOSTAT 2019), 연말 재고량이 154 만톤에 달하였다. 쌀 소비량을 늘릴 수 있는 방안으로 쌀 가공산 업 활성화가 이루어져야 하는데 아직 우리나라 쌀 가공업체는 영세하고, 밀에 비해 원료곡 가격 및 제분 비용이 높으며 제분 기술 등의 기반이 취약한 상황이다. 쌀가루는 습식, 반습식 및 건식의 제분방법에 의해 제조되는데, 고운 쌀가루를 제조하면서 손상전분을 줄일 수 있는 방법이 습식제분이다(Chiang & Yeh 2002). 그러나 습식 제분은 유통기간이 짧고 제조공정이 복잡하 여 가공비용이 높은 단점이 있어(Yeh 2004) 최근 개발된 기류식 제분기를 사용한 건식 제분 방법이 대안으로 검토되고 있다. 본 논문은 배유가 밀과 같은 형태의 연질이면서 전분구조가 둥근 형태를 가지고 있고, 건식쌀가루 품질이 우수한 건식제분 전용 신품종 '한가루'를 개발하였기에 품종의 육성 경위 및 주요 특성을 보고하고자 한다. 재료 및 방법 재배방법 및 농업특성 조사 본 시험은 '수원594호'를 2015~2016년 2년간 보통기에 중부 평야지 5개 지역과 호남평야지 1개 지역에서 '화성'을 대비품종

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Low temperature stress at the seedling stage of rice is an important factor causing the leaf discoloration, wilting and consequently leads to non-uniform crop maturation. In order to screen the cold tolerance elite lines efficiently, the five cold treatment conditions with different water and air temperature were designed and treated at seedling stage. For the evaluation of seedling tolerance, the injury was scored by visual rate and measured by Soil and Plant Analyzer Development (SPAD) meter. In the reactions of varieties for each treatment, the treatment 'B' condition, 12 o C mean water with 24 o C mean air, shows clear discoloration, so it's correlation coefficient was highest (r=−0.9, P＜0.0001) among the treatments. In the treatment condition for screening the cold-tolerance elite line, the cultivar, treatment and their interaction significantly affect the SPAD value. The 'A' treatment, 12 o C mean water with 34 o C mean air, was the best way to observe the variation between the elite lines. On the basis of the Duncan's test for SPAD value of cultivars, Keumo (moderate tolerant), Saetbyeol (sensitive) and Seolak (tolerant) were selected as check varieties. To study its impacts at the paddy field, the changes of crop characteristics such as height, panicle length, number of tiller and heading were investigated. In later growth period, the seedling treatment impact at the paddy field leads to heading delay. Due to the low temperature stress at the seedling stage induced by 12 o C mean cold water, Japonica and Tongil group shows the heading delay 4 to 7 and 8 to 11 days respectively.

As a first step of mapping genes conferring resistance to the brown planthopper, Nilaparvata lugens Stål, in Gayabyeo using a population derived from a cross between Gayabyeo and Taebaegbyeo, we performed the whole genome resequencing of these two Tongil-type rice varieties. The amount of raw sequence data was about 18.5X10 9 bp and 17.9X10 9 bp in Gayabyeo and Taebaegbyeo, respectively. After quality trimming and read mapping onto Nipponbare reference genome sequence, 9.3X10 9 bp was mapped in Gayabyeo with mapping depth of 25.0X, and 9.5X10 9 bp was mapped in Taebaegbyeo with mapping depth of 25.5X. Between Gayabyeo and Nipponbare, 1,585,880 SNPs were detected, while 1,416,898 SNPs were detected between Taebaegbyeo and Nipponbare. Between Gayabyeo and Taebaegbyeo, 284,501 SNPs were detected. Among the SNPs between Gayabyeo and Taebaegbyeo, 21.2% were in genic region and 78.8% were in intergenic region. In CDS region, 15,924 SNPs were detected, among which synonymous SNPs covered 47.3% and non-synonymous SNPs covered 52.7%. We designed Cleaved Amplified Polymorphic Sequences (CAPS) markers with SNPs in the restriction enzyme recognition sites, and 20 CAPS markers were tested. Of the 20 markers, 19 markers showed polymorphism and one marker showed monomorphism between Gayabyeo and Taebaegbyeo. It is expected that sufficient DNA markers for mapping genes with a population derived from a cross between Gayabyeo and Taebaegbyeo can be developed based on the results of the study.