인디카 벼는 일조시간이 짧은 열대지역에서 주로 재배하며, 자포니카 벼는 일조시간이 긴 한국, 일본, 및 중국(동북부 지역)을 포함하는 온대지역에서 재배한다. 최근 동남아 열대지역에서 자포니카 쌀에 대한 수요가 증가함에 따라 농촌진흥청은 필리핀 국제미작연구소(IRRI)와 공동으로 열대지역에 적응하는 다수성 온대 자포니카 벼 품종을 개발하고 있다. 일반적으로 자포니카 벼를 단일조건인 열대지역에 재배하면 이앙 후 바로 개화가 촉진되어 극조기 출수가 유도된다. 따라서 열대지역에 적응하는 자포니카 벼를 개발하기 위해서는 단일조건에서도 충분히 생장한 후 출수를 하는 특성이 우선적으로 필요하다. 본 연구는 국내 자포니카형 벼 품종인 ‘일품’과 미국에서 육성한 인디카형 벼인 ‘Zenith’를 교배한 F9 RIL 180 계통을 이용하여 필리핀의 단일조건하에서 재배하면서 출수기에 관련한 양적형질유전자좌(QTL) 분석을 수행한 바, 그 결과는 다음 과 같다. 1. 단일조건하에서 출수일수(파종~출수)에 관여하는 2종의 QTL(qHD6-SD와 qHD6-LD)을 탐색하였다. 2. 정밀지도제작 결과 qHD6-SD와 qHD6-LD은 모두 6번 염색체 Hd1 유전자를 포함하는 98 kb 영역에 존재하는 동일한 QTL인 것으로 나타났다 3. 시험계통을 필리핀 단일 조건에서 재배하였을 때 qHD6- SD 또는 qHD6-LD에서 Zenith allele형을 보유한 계통들은 일 품 allele형을 가진 계통들 보다 출수일수가 평균 8일 정도 길었다. 3. 시험계통을 한국의 장일 조건에서 재배하였을 때 qHD6- SD 또는 qHD6-LD에서 Zenith allele형을 보유한 계통들은 일품 allele형을 가진 계통들보다 출수일수가 평균 8일 정도 짧 았다. 4. 이러한 특성은 기존에 보고된 Hd1 유전자의 특성과 유사하여 qHD6-SD 및 qHD6-LD 은 Hd1 유전자일 가능성이 높은 것으로 나타났으며, 본 시험에서 사용한 Zenith는 nonfunctional Hd1 allele을 보유하는 것으로 추정되었다. 5. 이러한 결과를 통해 열대지역에 적응하는 자포니카 벼 육종연구에서 극조기 출수를 방지하고 충분한 출수일수를 확보하여 수량을 높이기 위해서는 인디카 벼가 주로 보유하고 있는 non-functional Hd1 allele을 반드시 도입해야 함을 재확인 하였다.

1. 본 연구는 우리나라 북부지역과 중국의 북한 인접지역에서 동일 품종을 재배하여 다양한 기후조건에서도 출수일수 변이계수가 안정적이고 조숙성인 품종을 선정하여 북한 적응성이 높은 품종선발에 기초자료로 활용하고자 수행된 연구결과이다. 2. 북한 접경 국내외 6개소에서 출수일수별로 극조생종, 조생종, 준조생종, 중생종의 4개 출수생태형으로 분류하였다. 국내에서는 극조생종에는 9품종, 조생종은 42품종, 준조생종은 17품종, 중생종은 4품종으로 분류되었고 중국에서는 극조생종 7품종, 조생종 27품종, 준조생종 32, 중생종 9품종으로 구분되었다. 3. ‘수원’ 등 국내 3개소에서 출수기의 변이계수는 4.8~ 18.5%이었고 변이계수가 6.0 이하인 품종은 태봉, 내풍, 화동, 운장, 인월, 진봉, 운봉, 금영, 삼천 등 이었다. 4. ‘단동’ 등 중국 3개소에서 출수기의 변이계수는 국내보다 낮은 0.5~8.1%로 변이계수가 2.0 이하인 품종은 태성, 진부찰, 중모1001, 오봉, 새상주, 중모1011, 삼천, 남원, 길주1호(북한 수집) 등 이었다. 5. 한국과 중국의 6개소에서 출수기 변이계수는 8.7~13.3% 의 범위를 보였고, 변이계수가 9.0% 이하로 낮은 품종은 국내 육성 품종 둔내, 운봉, 화동, 진부찰, 설레미 품종으로 북한의 벼 재배지역에서 적응성이 높을 것으로 판단된다. 대비품중으로 북한 대비품종인 원산69호, 중국 대비품종인 길주1호 등도 변이계수가 안정적인 품종이었다.

중부 평야지에서 중생종 벼 하이아미의 이앙시기에 따른 출수기의 변동과 출수 전후의 기상 및 수량 특성을 파악하고 적절한 재배시기를 제안하기 위하여, 이앙시기를 5월 10일부터 6월 24일까지 조절하여 3년간 국립식량과학원 중부작물부 수원 벼 재배시험 포장에서 시험한 결과는 다음과 같다. 1. 이앙기가 늦을수록 출수기까지는 일 평균기온이 높았으나 출수소요일수가 단축됨에 따라 적산온도가 적어졌고, 출수 후 40일간은 평균기온이 낮고 일조시간이 많은 경향이었다. 2. 이앙기~출수기와 출수 후 40일간의 평균기온은 시험연차보다 이앙시기에 따른 변이가 컸으나 일 평균 일조시간은 이앙시기 보다 시험연차에 따른 변이 정도가 더 커서, 이앙시기 조절에 의한 기상요인의 변화는 평균기온에서 뚜렷하게 나타났다. 3. 이앙시기가 늦어짐에 따라 수수는 감소하였으나 수당영화수가 증가하였고, 결과적으로 이앙시기 지연에 의한 출수소요일수의 단축이 sink size의 감소로 이어지지는 않았다. 4. 이앙시기 조절에 의한 m2당 영화수의 변화는 등숙비율과 뚜렷한 상관을 보이지 않았으나, 출수 후 40일간 평균기온이 낮아짐에 따라 현미천립중은 유의하게 증가하는 추세를 보였다. 5. 쌀수량은 이앙시기에 따라 유의차를 보이지 않았던 반면, 완전립 비율은 6월 24일까지 이앙이 늦어짐에 따라 높아지는 추세를 보였으며 그에 따라 완전미 수량도 비슷한 경향을 보였다. 6. 결과적으로, 중부 평야지에서 하이아미는 이앙시기를 6월 중~하순으로 늦춤으로써 쌀 품위를 높이고 완전미 수량을 향상시킬 수 있는 것으로 분석되었는데, 등숙 후기의 저온 피해 우려를 고려하면 6월 중순에 이앙하는 것이 안전할 것으로 판단된다.

Since Japonica rice is recognized as the premium rice in some subtropical region such as Philippines, the development of new cultivar adaptable in subtropical region has been conducting. However typical Japonica rice show earlier flowering in subtropical region due to the short day length and high temperature conditions. In such a condition, it is difficult to secure enough yields. Therefore it is need that selection of Japonica cultivar showing suitable heading characters in subtropical region. Here we try to check the basic vegetative phase and heading sensitivity on temperature condition using 37 kinds of Korean cultivars. BVP is between 14 to 39 days and 37% of cultivar had basic vegetative phase between 26 to 30 days. When temperature became lower on sensitive and reproductive stage, heading was more delayed. However the 24oC condition showed the greatest impact on heading delay among temperature condition. Among cultivars, 56% of cultivars have basic vegetative phase over 25days.We checked temperature effect on heading especially sensitivity stage in those materials. Joun, Manho, Joan and Cheonga showed stable heading date under different temperature conditions. With this data, we suggest that Joun, Manho, Joan and Cheonga could be a good cultivar in subtropical region in heading characters.

‘Palbangmi’ is a super high-yield rice cultivar bred by interspecies cross between Tongil type and Africa rice. But, ‘Palbangmi’ has a problem in grain maturation which results in rice yield decreases. Because ‘Palbangmi’ is Tongil and Africa rice interspecies-crossed cultivar, it would be predicted to require higher temperature for grain maturation than japonica rice. Therefore, ‘Palbangmi’ would be required to determine Late Marginal Heading Date (LMHD) for normal maturation. In this study, experiment of transplanting date was carried out to determine LMHD of ‘Palbangmi’ in Suwon and Iksan for 3 years. When daily mean temperature was below 23oC, grain filling ratio (%) increased about 8% for each 1oC. On the other hands, grain filling ratio (%) didn't increase when the daily mean temperature was above 23oC. Therefore, it is determined that 23oC is adequate for minimum threshold temperature for grain maturation. The LMHD of ‘Palbangmi’ was determined from calculated heading dates for each year which could satisfy threshold temperature for 40 days after heading during last 15 years. As a results, LMHD was earlier than August 1 in 16 regions where it is inadequate for ‘Palbangmi’. Continually, LMHD was August 1 ~ August 5 in 13 regions, August 6 ~ August 10 in 14 regions and August 11 ~ August 15 in 21 regions. Finally, LMHD was later than August 15 in 14 regions. Considering that heading date of ‘Palbangmi’ is August 13 as mid maturing ecotype, it is suggested that earlier transplanting required for normal maturing in almost areas except south plain area and some areas of central plain area.

벼줄기굴파리의 2화기 피해에 있어서, 이삭 및 잎의 피해양상과 용위화치를 조사한 결과를 요약하면 다음과 같다. 1) 상수율과 공흔발생에 있어, 통일계가 일반계에 비해 높았다. 2) 상수의 피해위치에 있어, 일반적으로 출수기가 이를수록 이삭 하부에, 늦을수록 이삭 상부에 피해를 받았다. 3) 통일계에 있어, 상부 또는 중부 피해 이삭경에 있어서는 상엽에 공흔, 1엽에 무공흔의 경우가 가장 많았고, 하부피해이삭경에서는 모두 무공흔의 경우가 가장 많았다. 4) 용화위치는 지엽과 1엽의 엽초내이었으며, 특히 지엽에 현저히 많았다.

Heading time is important element for yield and quality in crops. Among day length and temperature which influence on heading, temperature effect has not been investigated well. To investigate temperature effect on heading, heading date and plant growth characters were checked under the low and high temperature conditions in short day length. Analyzing heading date of six Korean varieties under the high and low temperature condition, heading date of varieties were delayed under low temperature. In the low temperature condition, dry weight and area of leaf were reduced. Varieties showing more delay of heading under low temperature also showed more reduction in leaf area. After selecting three varieties showing significant difference in leaf growth and heading date under different temperature conditions, nutrient contents of plant were analyzed. Nitrogen content was reduced in leaf and shoot under the low temperature condition. OsNRT2.3, nitrate transporter, was significantly down regulated in varieties showing more heading delay. Available phosphate content was decreased in leaf, but increased in shoot due to reduction of phosphate mobility. OsPT1, phosphate transporter regulating phosphate uptake, was more down regulated in varieties showing more heading delay. OsPT6, phosphate transporter regulating phosphate transport in plant, was also significantly down regulated in those varieties. With these data, we expected that active nitrogen and available phosphate uptake and transport in plant would increase leaf growth then might reduce heading delay under the low temperature condition.

In recent years, the efficiency and accuracy of QTL analysis for identification of useful traits have been increased by high-throughput genotyping. In a previous study, the genome variation of significant DNA polymorphism was observed in early maturing type rice mutant (EMT) by comparing with that of wild type (WT). For detection of major QTL for flowering time, we constructed a linkage map of 36 InDel- and 6 SNP- markers. In the linkage analysis of F2 plants derived from the cross “WT x EMT”, we have detected one potential QTL region on chromosome 6 by M6-3 marker. Also, the Hd1, which contained the target fragment of M6-3 marker, exhibited the relatively high nonsynonymous substitutions in genes located on chromosomal region from M6-2 to M6-4. To evaluate the reliable allele segregation related to expected Mendelian ratio between M6-3 and its flanking markers, M6-3 marker developed in Hd1 gene exhibited the 1:2:1 ratio as clear monogenic segregation in heterozygous F3 plant. Additionally, we further analyzed the different transcript regulations of OsGI and Hd3a gene related to Hd1 involved in photoperiodic flowering pathway. Although the mRNA levels of Hd1 had no difference between WT and EMT, the Hd3a as downstream effector of Hd1 significantly upregulated in EMT, suggesting that Hd1 gene may become nonfunctional.

Heading date and photoperiod sensitivity are fundamental traits that determine rice adaptation to a wide range of geographic environments. By quantitative trait locus (QTL) mapping and candidate gene analysis using wholegenome re-sequencing, we found that Oryza sativa Pseudo-Response Regulator37 (OsPRR37; hereafter PRR37) is responsible for the Early heading7-2 (EH7-2)/Heading date2 (Hd2) QTL which was identified from a cross of late-heading rice ‘Milyang23 (M23)’ and early-heading rice ‘H143’. H143 contains a missense mutation of an invariantly conserved amino acid in the CCT (CONSTANS, CO-like, and TOC1) domain of PRR37 protein. In the world rice collection, different types of nonfunctional PRR37 alleles were found in many European and Asian rice cultivars. Notably, the japonica varieties harboring nonfunctional alleles of both Ghd7/Hd4 and PRR37/Hd2 flower extremely early under natural long-day conditions, and are adapted to the northernmost regions of rice cultivation, up to 53° N latitude. Genetic analysis revealed that the effects of PRR37 and Ghd7 alleles on heading date are additive, and PRR37 down-regulates Hd3a expression to suppress flowering under long-day conditions. Our results demonstrate that natural variations in PRR37/Hd2 and Ghd7/Hd4 have contributed to the expansion of rice cultivation to temperate and cooler regions

Using a series of BC8F4 nearly isogenic lines(IL-20) derived from a cross between Hwaseongbyeo, as the recurrent parent, and wild rice Oryza minuta (IRGC Acc. No. 101144) as the donor parent we constructed a high-resolution physical map for the days to heading (dth9)-QTL. dth9 QTL was mapped to the long arm of chromosome 9 across a 34.74-kb region containing 8 predicted genes. Heading date of Japonica rice variety Hwaseongbyeo was one week earlier than a near-isogenic line (NILs) IL-20 under natural field (NF) conditions and 3-4 days under short-day (SD) conditions implying that the dth9-QTL is involved in photoperiod sensitivity in rice. Of the 8 predicted genes three were protein-coding genes in dth9-QTL region. According to RiceXpro published data, micro-array analysis of different leaf developmental stages of Nipponbare showed a higher level of LOC_Os09g36700 mRNA expression during panicle initiation stage. This data further supported our prediction that dth9 locus is responsible for delayed heading in IL-20. Previous studies showed that RNase T2 family proteins are involved in photoperiod sensitivity. Based on these findings we sequenced two candidate genes, which encoded for RNase T2 family proteins. Interestingly, we found the existence of a missense mutation in LOC_Os09g36700 gene suggesting that dth9-QTL might control difference in days to heading between Hwaseongbyeo and IL-20. The QTL for days to heading had not been detected in previous QTL studies between Oryza cultivars, indicating the existence of potentially novel allele from O. mimuta.

The timing of flowering, which is of crucial importance for plant growth and survival, is controlled by intricate pathways. To identify heading date-QTL, we constructed high resolution map on chromosome 3 using heterogeneous inbred family-near isogenic lines (H-NILs) derived from F7 RILs generated by the cross of early-heading japonica rice ‘H143’ and middle-late-heading indica-japonica hybrid cultivar ‘Milyang23’. QTL and subsequent sequence analysis using H-NILs revealed that the gene underlining QTL EH3, which is detected in the region of Hd16, is EL1 encoding casein kinase I (CKI). Two types of single amino acid substitutions in Ser/Thr kinase domain of EL1 were found in various cultivars, among which H-NIL(eh3) caused loss of function in EL1 demonstrated by altered heading date and GA response. Moreover, the phosphorylation of EL1 appears to involve in EL1 activity to regulate heading date. Transcriptional analysis clearly indicated that H-NIL(EH3) suppresses heading under LD conditions by down-regulating Ehd1, there by Hd3a and RFT1 expressions were not induced, suggesting that EL1 is photoperiod-sensitive and functions as a LD-specific suppressor of heading. Further characterization suggested that EL1 is likely to involve in anther development and seed settings by regulating GAMYB expression. Our study demonstrated that the genetic basis of natural variation occurred in ‘H143’ was revealed by QTL analysis using H-NILs, and EH3/EL1 function is crucial for heading and development in rice. The genetic natural variation of H-NIL(eh3) may have contributed to adaptation of rice cultivation to the higher regions by regulating the expression of rice flowering activator genes and GA signaling.

Mutation breeding is characterized by its merit, creation of new mutant characters and addition of very few traits without disturbing other characters of variety. Gamma ray is generally used to induce mutation in various crops. Heading dat is one of the key factors in the regional and seasonal adaptation of rice verity. This study was carried out to evaluate agronomic characteristics, genetic variation and grain quality of early heading rice (Oryza sativa L. cv. Dongjin 1) lines derived from gamma-ray (Co60, 300 Gy) irradiation. The average heading date of the early heading lines in M7 and M8 generation was faster than that of mother verity as 11 (line γ-2), 10 Aug (line γ-5), 6 Aug (γ-1 line), 5 Aug (γ-3 and X-1), 4 (line γ-4) days, respectively. The selected lines showed shorter culm length and ear length compared with the control. Total spikelets per panicle, percent ripened grain and thousand grain weight of the lines were also mostly shorter or lower than those of the control except total spikelets per panicle of γ-4 and γ-5 lines. When genetic variations of rps16-trnK region were evaluated by nucleotide analysis, nucleotide length of the rps16-trnK region was 664 bp in all the early-heading lines and control. Out of 5 sites of nucleotide transposition detected in the region, however, 2 sites were appeared only in the early-heading lines. Amylose content of the early heading lines ranged from 18.3% to 18.4% and the content was included in high eating quality. Protein content of the lines ranged from 6.6% to 7.0%. The content belonged to Top-rice showing under 7% of protein content. Toyo taste value of the lines ranged from 76.3% to 84.8%.

최근 개발된 직파재배의 일종인 무논점파는 무논점파기(8조식, 15×28cm , 주당 5~8립)를 이용하여 파종하므로 이앙재배의 재식거리와 유사한 밀도를 유지할 수 있는 장점이 있다. 벼 무논점파재배의 생육 및 출수특성과 출수일변동에 따른 등숙율과 완전립율의 변이를 알아보고자 국립식량과학원 답작과 논포장(수원)에서 2009년부터 2011년까지 3년동안 본 시험을 수행하였다. 1. 무논점파는 입모수는 기계이앙의 재식밀도와 큰 차이가 없었으나 분얼수가 많아 최고분얼기에 단위면적당 경수는 기계이앙의 1.3~2배였다. 최고분얼기 이후 분얼수는 감소해 성숙기 이삭수는 기계이앙과 큰 차이가 없었다. 2. 무논점파의 출수전 생육일수는 운광벼 84일, 호품벼 98일로 기계이앙의 파종일로부터 14일, 19일의 재배기간이 단축되었다. 3. 무논점파의 성숙기 생육특성은 간장과 수장 및 면적당 이삭수는 기계이앙과 차이가 없었다. 통계적 유의성은 없었으나 수당립수는 많아지는 경향이었다. 4. 출수기는 무논점파가 이앙보다 운광벼는 9일, 호품벼는 3일 늦어졌는데 호품벼의 연차간 변이가 작았다. 호품벼는 출수기간이 기계이앙보다 2일 짧아 동시출수율이 높았다. 4. 무논점파재배시 출수일변이에 따른 등숙율과 현미완 전립율은 기계이앙과 차이가 없거나 오히려 높은 것으로 나타났으나 조생종인 운광벼보다 중만생종인 호품벼의 연차간 변이가 적어 무논점파 안정성이 우수한 것으로 나타났다.

This study was undertaken to determine how different harvesting times affected the nutritional compositions in two forage rice varieties(Nokyangbyeo, Dasanbyeo). The contents of crude protein in leaf and stem decreased, with time, after heading in Nokyangbyeo, Dasanbyeo, but there was not so changed in that of spikes. Contents of Neutral Detergent Fiber(NDF) and Acid Detergent Fiber(ADF) in leaf and stem increased slightly but decreased rapidly in these of spikes. Contents of Total Digestive Nutrient(TDN) in spikes was the highest compared to that of the other parts of plants. Contents of Total Digestive Nutrient(TDN) in plants was the highest at 40 days after heading in Nokyangbyeo and was the highest at 50 days after heading in Dasanbyeo.

This study was undertaken to determine how different seeding methods and harvesting times affected the biomass partitioning of forage rice. Two rice varieties(Nokyangbyeo, Dasanbyeo) were planted by 4 different seeding method(rice transplanting, direct seeding on dry paddy, water hill seeding, water seeding). The heading date was delayed more than 10 days in water seeding and water hill seeding compared to that of rice transplanting method. The biomass production by harvesting times was the highest at 50 days after heading in two rice varieties and was high in order of direct seeding on dry paddy〉water hill seeding〉rice transplanting〉water seeding in seeding methods. The ratios of spikes dry weight to total dry weight increased, with time, after heading. But the ratio of leaf and stem dry weight to total dry weight decreased, with time, after heading.