研究者詳細 - 山本　敏央

論文 - 山本　敏央

分割表示 98 件中 61 - 80 件目／全件表示 >>

Molecular distinction in genetic regulation of nonphotochemical quenching in rice 査読

Ichiro Kasajima, Kaworu Ebana, Toshio Yamamoto, Kentaro Takahara, Masahiro Yano, Maki Kawai-Yamada, Hirofumi Uchimiya

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 108 ( 33 ) 13835 - 13840 2011年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATL ACAD SCIENCES

Nonphotochemical quenching (NPQ) regulates energy conversion in photosystem II and protects plants from photoinhibition. Here we analyze NPQ capacity in a number of rice cultivars. NPQ was strongly induced under medium and high light intensities in rice leaves. Japonica cultivars generally showed higher NPQ capacities than Indica cultivars when we measured a rice core collection. We mapped NPQ regulator and identified a locus (qNPQ1-2) that seems to be responsible for the difference in NPQ capacity between Indica and Japonica. One of the two rice PsbS homologues (OsPsbS1) was found within the qNPQ1-2 region. PsbS protein was not accumulated in the leaf blade of the mutant harboring transferred DNA insertion in OsPsbS1. NPQ capacity increased as OsPsbS1 expression increased in a series of transgenic lines ectopically expressing OsPsbS1 in an Indica cultivar. Indica cultivars lack a 2.7-kb region at the point 0.4 kb upstream of the OsPsbS1 gene, suggesting evolutionary discrimination of this gene.

DOI： 10.1073/pnas.1104809108

Detection of a QTL for accumulating Cd in rice that enables efficient Cd phytoextraction from soil (vol 61, pg 43, 2011) 査読

Tadashi Abe, Fumio Taguchi-Shiobara, Yoichiro Kojima, Takeshi Ebitani, Masato Kuramata, Toshio Yamamoto, Masahiro Yano, Satoru Ishikawa

BREEDING SCIENCE 61 ( 2 ) 221 - 221 2011年6月

Identification of Chromosomal Regions Controlling the Leaf Photosynthetic Rate in Rice by Using a Progeny from Japonica and High-yielding Indica Varieties 査読

Shunsuke Adachi, Naoko Nito, Motohiko Kondo, Toshio Yamamoto, Yumiko Arai-Sanoh, Tsuyu Ando, Taiichiro Ookawa, Masahiro Yano, Tadashi Hirasawa

PLANT PRODUCTION SCIENCE 14 ( 2 ) 118 - 127 2011年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CROP SCIENCE SOC JAPAN

The whole-leaf photosynthetic rate in rice plants is controlled by various physiological processes. In a high-yielding indica rice variety, Habataki, the leaf photosynthetic rate (LPR) of the uppermost fully expanded leaves was approximately 130 to 140% of that in a japonica variety, Sasanishiki, from booting to the early ripening stage. We characterized the difference in the LPR between Habataki and Sasanishiki Leaves of Habataki contained higher levels of nitrogen and, as a consequence, of Rubisco, and had higher stomatal conductance that was associated with higher hydraulic conductance from roots to leaves than those of Sasanishiki. These features were responsible for the higher LPR of Habataki. An analysis of chromosome segment substitution lines (CSSLs) in which chromosome segments from Habataki were substituted into the genetic background of Sasanishiki showed that three genetic regions on chromosomes 4, 5 and 11 were responsible for the increase in the LPR. Each of these regions was estimated to increase the LPR by 15 to 30%, and we showed that they were associated with higher activity of mesophyll photosynthesis due to higher leaf nitrogen content and greater stomatal conductance. Leaf nitrogen content and stomatal conductance may be useful parameters for further quantitative trait locus analysis of efficient photosynthesis in leaves.

DOI： 10.1626/pps.14.118

Identification and characterization of genomic regions on chromosomes 4 and 8 that control the rate of photosynthesis in rice leaves 査読

Shunsuke Adachi, Yukiko Tsuru, Naoko Nito, Kazumasa Murata, Toshio Yamamoto, Takeshi Ebitani, Taiichiro Ookawa, Tadashi Hirasawa

JOURNAL OF EXPERIMENTAL BOTANY 62 ( 6 ) 1927 - 1938 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

DNA marker-assisted selection appears to be a promising strategy for improving rates of leaf photosynthesis in rice. The rate of leaf photosynthesis was significantly higher in a high-yielding indica variety, Habataki, than in the most popular Japanese variety, Koshihikari, at the full heading stage as a result of the higher level of leaf nitrogen at the same rate of application of nitrogen and the higher stomatal conductance even when the respective levels of leaf nitrogen were the same. The higher leaf nitrogen content of Habataki was caused by the greater accumulation of nitrogen by plants. The higher stomatal conductance of Habataki was caused by the higher hydraulic conductance. Using progeny populations and selected lines derived from a cross between Koshihikari and Habataki, it was possible to identify the genomic regions responsible for the rate of photosynthesis within a 2.1 Mb region between RM17459 and RM17552 and within a 1.2 Mb region between RM6999 and RM22529 on the long arm of chromosome 4 and on the short arm of chromosome 8, respectively. The designated region on chromosome 4 of Habataki was responsible for both the increase in the nitrogen content of leaves and hydraulic conductance in the plant by increasing the root surface area. The designated region on chromosome 8 of Habataki was responsible for the increase in hydraulic conductance by increasing the root hydraulic conductivity. The results suggest that it may be possible to improve photosynthesis in rice leaves by marker-assisted selection that focuses on these regions of chromosomes 4 and 8.

DOI： 10.1093/jxb/erq387

Detection of a QTL for accumulating Cd in rice that enables efficient Cd phytoextraction from soil 査読

Tadashi Abe, Fumio Taguchi-Shiobara, Yoichiro Kojima, Takeshi Ebitani, Masato Kuramata, Toshio Yamamoto, Masahiro Yano, Satoru Ishikawa

BREEDING SCIENCE 61 ( 1 ) 43 - 51 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPANESE SOC BREEDING

Phytoextraction by high-cadmium (Cd)-accumulating rice (Oryza saliva L.) cultivars has been proposed as an attractive technique for cleaning up Cd-contaminated paddy field soil. To breed rice cultivars useful for Cd phytoextraction, it is necessary to understand the genetic basis of Cd accumulation in aerial parts. We developed backcross inbred lines (BILs) derived from a cross between a low-Cd-accumulating cultivar, Koshihikari (japonica), and a relatively high-Cd-accumulating cultivar, Jarjan (indica). The BILs were grown in fields containing two low levels of Cd and in pots of soil containing a moderate level of Cd. A quantitative trait locus (QTL) analysis revealed that a major QTL, qCdp7 (QTL potentially useful for Cd-phytoextraction on chromosome 7) contributed to accumulation of Cd in both brown rice and straw of plants grown in any of the three soils, and it accounted for 31% to 54% of the phenotypic variance. To confirm the phytoextraction-promotion ability of qCdp7, we grew BILs carrying the Jarjan allele of qCdp7 in Cd-contaminated soil, and confirmed the reduction of the Cd concentration in the shoots of Koshihikari subsequently grown in the phytoextracted soil. These results demonstrate that the Jarjan qCdp7 allele is effective at phytoextracting Cd from the soil.

DOI： 10.1270/jsbbs.61.43

Evaluation of yield performance in rice near-isogenic lines with increased spikelet number 査読

Akihiro Ohsumi, Toshiyuki Takai, Masashi Ida, Toshio Yamamoto, Yumiko Arai-Sanoh, Masahiro Yano, Tsuyu Ando, Motohiko Kondo

FIELD CROPS RESEARCH 120 ( 1 ) 68 - 75 2011年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Rice yield potential is determined by the balance between sink size and source capacity. To clarify the factors that limit yield in temperate japonica cultivars, we compared the yield performance of Sasanishiki, a temperate japonica cultivar, with those of three near-isogenic lines (NILs) of Sasanishiki with introgression of quantitative trait loci (QTL) derived from a high-yielding indica cultivar, Habataki: qSBN1, which increases the number of secondary rachis branches; qPBN6, which increases the number of primary rachis branches; and a pyramid line that combines these two QTLs. NIL (SBN1), NIL (PBN6), and NIL (SBN1 + PBN6) produced 28-37%, 9-16%, and 62-65% more spikelets per panicle than Sasanishiki, respectively. However, the NILs with increased spikelet number per panicle did not increase grain yield significantly, because compensation is taken place among different yield components. The pyramid line nevertheless had 4-12% higher yield than Sasanishiki due to greater translocation of carbohydrates from stem to panicle. There was no difference in carbohydrate accumulation before heading or in biomass production among Sasanishiki and the three NILs. The results indicate that increasing sink size does not substantially improve yield in Sasanishiki, which lacks sufficient substrate supply to fully satisfy the increased sink demand that results from the spikelet-number QTLs. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fcr.2010.08.013

Characterization of a rice variety with high hydraulic conductance and identification of the chromosome region responsible using chromosome segment substitution lines 査読

Shunsuke Adachi, Yukiko Tsuru, Motohiko Kondo, Toshio Yamamoto, Yumiko Arai-Sanoh, Tsuyu Ando, Taiichiro Ookawa, Masahiro Yano, Tadashi Hirasawa

ANNALS OF BOTANY 106 ( 5 ) 803 - 811 2010年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

The rate of photosynthesis in paddy rice often decreases at noon on sunny days because of water stress, even under submerged conditions. Maintenance of higher rates of photosynthesis during the day might improve both yield and dry matter production in paddy rice. A high-yielding indica variety, 'Habataki', maintains a high rate of leaf photosynthesis during the daytime because of the higher hydraulic conductance from roots to leaves than in the standard japonica variety 'Sasanishiki'. This research was conducted to characterize the trait responsible for the higher hydraulic conductance in 'Habataki' and identified a chromosome region for the high hydraulic conductance.
Hydraulic conductance to passive water transport and to osmotic water transport was determined for plants under intense transpiration and for plants without transpiration, respectively. The varietal difference in hydraulic conductance was examined with respect to root surface area and hydraulic conductivity (hydraulic conductance per root surface area, L(p)). To identify the chromosome region responsible for higher hydraulic conductance, chromosome segment substitution lines (CSSLs) derived from a cross between 'Sasanishiki' and 'Habataki' were used.
The significantly higher hydraulic conductance resulted from the larger root surface area not from L(p) in 'Habataki'. A chromosome region associated with the elevated hydraulic conductance was detected between RM3916 and RM2431 on the long arm of chromosome 4. The CSSL, in which this region was substituted with the 'Habataki' chromosome segment in the 'Sasanishiki' background, had a larger root mass than 'Sasanishiki'.
The trait for increasing plant hydraulic conductance and, therefore, maintaining the higher rate of leaf photosynthesis under the conditions of intense transpiration in 'Habataki' was identified, and it was estimated that there is at least one chromosome region for the trait located on chromosome 4.

DOI： 10.1093/aob/mcq175

Q-TARO: QTL Annotation Rice Online Database 査読

Jun-ichi Yonemaru, Toshio Yamamoto, Shuichi Fukuoka, Yusaku Uga, Kiyosumi Hori, Masahiro Yano

RICE 3 ( 2-3 ) 194 - 203 2010年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Over the past two decades, genetic dissection of complex phenotypes of economic and biological interest has revealed the chromosomal locations of many quantitative trait loci (QTLs) in rice and their contributions to phenotypic variation. Mapping resolution has varied considerably among QTL studies owing to differences in population size and number of DNA markers used. Additionally, the same QTLs have often been reported with different locus designations. This situation has made it difficult to determine allelic relationships among QTLs and to compare their positions. To facilitate reliable comparisons of rice QTLs, we extracted QTL information from published research papers and constructed a database of 1,051 representative QTLs, which we classified into 21 trait categories. This database (QTL Annotation Rice Online database; Q-TARO, http://qtaro.abr.affrc.go.jp/) consists of two web interfaces. One interface is a table containing information on the mapping of each QTL and its genetic parameters. The other interface is a genome viewer for viewing genomic locations of the QTLs. Q-TARO clearly displays the co-localization of QTLs and distribution of QTL clusters on the rice genome.

DOI： 10.1007/s12284-010-9041-z

Integration of Genomics into Rice Breeding 査読

Shuichi Fukuoka, Kaworu Ebana, Toshio Yamamoto, Masahiro Yano

RICE 3 ( 2-3 ) 131 - 137 2010年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

One of the major challenges in genetics has been to identify the nucleotide polymorphisms responsible for phenotypic variation. Through intensive analysis, several major quantitative trait loci (QTLs) for agronomic traits in rice have been identified and the underlying candidate genes have been delimited. Advanced mapping populations, including chromosome segment substitution lines, have enhanced the power of genetic analysis to detect QTL alleles, even those with minor effects. Recent examples of marker-assisted selection have proven the potential of this strategy for crop improvement. The genome-wide discovery of single nucleotide polymorphisms (SNPs), even among closely related cultivars, has enhanced the power of allele mining in a wide range of rice breeding materials. An array-based SNP genotyping system can be used to visualize pedigree haplotypes in breeding materials, including landraces and modern cultivars. All of these technologies are accelerating the genetic dissection of complex agronomic traits and further improvement of rice.

DOI： 10.1007/s12284-010-9044-9

A Quantitative Trait Locus for Chlorophyll Content and its Association with Leaf Photosynthesis in Rice 査読

Toshiyuki Takai, Motohiko Kondo, Masahiro Yano, Toshio Yamamoto

RICE 3 ( 2-3 ) 172 - 180 2010年9月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Leaf photosynthesis, an important determinant of yield potential in rice, can be estimated from measurements of chlorophyll content. We searched for quantitative trait loci (QTLs) for Soil and Plant Analyzer Development (SPAD) value, an index of leaf chlorophyll content, and assessed their association with leaf photosynthesis. QTL analysis derived from a cross between japonica cultivar Sasanishiki and high-yielding indica cultivar Habataki detected a QTL for SPAD value on chromosome 4. This QTL explained 31% of the total phenotypic variance, and the Habataki allele increased the SPAD value. Chromosomal segment substitution line (CSSL) with the corresponding segment from Habataki had a higher leaf photosynthetic rate and SPAD value than Sasanishiki, suggesting an association between SPAD value and leaf photosynthesis. The CSSL also had a lower specific leaf area (SLA) than Sasanishiki, reflecting its thicker leaves. Substitution mapping under Sasanishiki genetic background demonstrated that QTLs for SPAD value and SLA were co-localized in the 1,798-kb interval. The results suggest that the phenotypes for SPAD value and SLA are controlled by a single locus or two tightly linked loci, and may play an important role in increasing leaf photosynthesis by increasing chlorophyll content or leaf thickness, or both.

DOI： 10.1007/s12284-010-9047-6

Fine definition of the pedigree haplotypes of closely related rice cultivars by means of genome-wide discovery of single-nucleotide polymorphisms 査読

Toshio Yamamoto, Hideki Nagasaki, Jun-ichi Yonemaru, Kaworu Ebana, Maiko Nakajima, Taeko Shibaya, Masahiro Yano

BMC GENOMICS 11 267 2010年4月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BIOMED CENTRAL LTD

Background: To create useful gene combinations in crop breeding, it is necessary to clarify the dynamics of the genome composition created by breeding practices. A large quantity of single-nucleotide polymorphism (SNP) data is required to permit discrimination of chromosome segments among modern cultivars, which are genetically related. Here, we used a high-throughput sequencer to conduct whole-genome sequencing of an elite Japanese rice cultivar, Koshihikari, which is closely related to Nipponbare, whose genome sequencing has been completed. Then we designed a high-throughput typing array based on the SNP information by comparison of the two sequences. Finally, we applied this array to analyze historical representative rice cultivars to understand the dynamics of their genome composition.
Results: The total 5.89-Gb sequence for Koshihikari, equivalent to 15.7x the entire rice genome, was mapped using the Pseudomolecules 4.0 database for Nipponbare. The resultant Koshihikari genome sequence corresponded to 80.1% of the Nipponbare sequence and led to the identification of 67 051 SNPs. A high-throughput typing array consisting of 1917 SNP sites distributed throughout the genome was designed to genotype 151 representative Japanese cultivars that have been grown during the past 150 years. We could identify the ancestral origin of the pedigree haplotypes in 60.9% of the Koshihikari genome and 18 consensus haplotype blocks which are inherited from traditional landraces to current improved varieties. Moreover, it was predicted that modern breeding practices have generally decreased genetic diversity
Conclusions: Detection of genome-wide SNPs by both high-throughput sequencer and typing array made it possible to evaluate genomic composition of genetically related rice varieties. With the aid of their pedigree information, we clarified the dynamics of chromosome recombination during the historical rice breeding process. We also found several genomic regions decreasing genetic diversity which might be caused by a recent human selection in rice breeding. The definition of pedigree haplotypes by means of genome-wide SNPs will facilitate next-generation breeding of rice and other crops.

DOI： 10.1186/1471-2164-11-267

リーフスターとタカナリの交雑後代を用いた水稲の極強稈形質に関する量的形質遺伝子座の解析

酒井幸, 山本敏央, 矢野昌裕, 河野いづみ, 平沢正, 大川泰一郎

日本作物學會紀事 79 352 - 353 2010年3月

コシヒカリ/タカナリの戻し交雑自殖(BC_1F_6)系統群を用いた光合成速度に関わる形質の量的形質遺伝子座(QTL)解析

内田万咲, 早田一也, 高井俊之, 山本敏央, 大川泰一郎, 矢野昌裕, 平沢正

日本作物學會紀事 79 96 - 97 2010年3月

登熟期における水稲葉身傾斜角度の量的形質遺伝子座(QTL)解析-コシヒカリ/タカナリの戻し交雑自殖(BC_1F_6)系統群を用いて

早田一也, 高井俊之, 山本敏央, 大川泰一郎, 矢野昌裕, 平沢正

日本作物學會紀事 79 98 - 99 2010年3月

A major quantitative trait locus for increasing cadmium-specific concentration in rice grain is located on the short arm of chromosome 7 査読

Satoru Ishikawa, Tadashi Abe, Masato Kuramata, Masayuki Yamaguchi, Tsuyu Ando, Toshio Yamamoto, Masahiro Yano

JOURNAL OF EXPERIMENTAL BOTANY 61 ( 3 ) 923 - 934 2010年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Large phenotypic variations in the cadmium (Cd) concentration of rice grains and shoots have been observed. However, the genetic control of Cd accumulation remains poorly understood. Quantitative trait loci (QTLs) determining the grain Cd concentration of rice grown in a Cd-polluted paddy field were identified. Using a mapping population consisting of 85 backcross inbred lines derived from a cross between the low-Cd-accumulating cultivar Sasanishiki (japonica) and high-Cd-accumulating cultivar Habataki (indica), two QTLs for increasing grain Cd concentration were found on chromosomes 2 and 7. A major-effect QTL, qGCd7 (QTL for grain Cd on chromosome 7), was detected on the short arm of chromosome 7. It accounted for 35.5% of all phenotypic variance in backcross inbred lines. qGCd7 was not genetically related to any QTLs for concentrations of essential trace metals (Cu, Fe, Mn, and Zn) or those for agronomic traits such as heading date, suggesting that this QTL is specific to Cd. Furthermore, the existence of qGCd7 was confirmed using chromosome segment substitution lines (CSSLs) and an F(2) population from a cross between the target CSSL and Sasanishiki grown in a Cd-polluted paddy soil. To our knowledge, qGCd7 is a novel QTL with major effects for increasing grain Cd concentrations.

DOI： 10.1093/jxb/erp360

Canopy temperature on clear and cloudy days can be used to estimate varietal differences in stomatal conductance in rice 査読

Toshiyuki Takai, Masahiro Yano, Toshio Yamamoto

FIELD CROPS RESEARCH 115 ( 2 ) 165 - 170 2010年1月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Leaf photosynthetic potential, a major determinant of yield potential in rice, is mostly explained by stomatal conductance (g(s)) as well as leaf N content (Rubisco protein content). Therefore, the rapid and precise evaluation of g(s) as well as leaf N content would be a valuable addition to rice breeding programs aimed at improved yield potential. We established a simple method based on infrared thermography to estimate varietal differences in g(s). Seven rice varieties were cultivated in two-row plots in 2007, and canopy temperatures in three varieties, including a control variety, Koshihikari, were simultaneously measured to determine canopy temperature difference (CTd) between Koshihikari and the other varieties on clear days. The varieties Takanari, Habataki, and TUAT1-5-6a displayed significantly (P < 0.05) lower leaf temperature and higher g(s) and leaf photosynthetic rate (P(n)) than Koshihikari. CTd was closely correlated with g(s) and P(n). These results indicate that CTd may be useful as a relative index to estimate varietal differences in g(s). A significant CTd was still observed even under cloudy conditions in 2008. Takanari and TUAT1-5-6a had lower leaf temperature than Koshihikari on cloudy days as well as on clear days. Subsequent investigation of photosynthetic light response curves revealed that Takanari and TUAT1-5-6a had higher g(s) and P(n) than Koshihikari under lower irradiance. These results suggest that infrared thermography may be a simple method of evaluating varietal differences in g(s) through CTd, and that it may be practicable even under cloudy conditions. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fcr.2009.10.019

Isolation and functional analysis of the gene controlling the stub-spreading trait in rice (Oryza sativa L.) 査読

T. Komori, M. Miyata, T. Yamamoto, N. Nitta, Y. Hiei, M. Yano, J. Ueki, T. Komari

PLANT BREEDING 128 ( 6 ) 568 - 575 2009年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL PUBLISHING, INC

The stub-spreading trait, also designated as 'tiller angle', is one of the components that determine the plant type. In rice, the trait is quite important because of its close relationship to the yield performance. The Spk(t) gene is a major determinant of the trait in the cross of 'Kasalath' (indica) and 'Nipponbare' (japonica). In this study, the Spk(t) gene was isolated by a map-based cloning strategy. Sequence analysis of the cDNA clones from the locus revealed that the Spk(t) transcripts and the spk(t) transcripts encode identical 259-aa proteins of unknown function; however, the structure of the 3'-untranslated region of each allele is quite different. Additional transgenic experiments in rice demonstrated that the difference is caused by a single-nucleotide polymorphism at the 3'-splicing site specific to the Spk(t) allele which thereby plays a critical role in the phenotypic expression. In addition to revealing the molecular mechanism underlying the allele differentiation at the Spk(t) locus, the information presented here should be useful for breeding of this trait in rice.

DOI： 10.1111/j.1439-0523.2009.01639.x

A novel quantitative trait locus, qCL1, involved in semi-dwarfism derived from Japanese rice cultivar Nipponbare 査読

Kiyosumi Hori, Toshio Yamamoto, Kaworu Ebana, Yoshinobu Takeuchi, Masahiro Yano

BREEDING SCIENCE 59 ( 3 ) 285 - 295 2009年9月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPANESE SOC BREEDING

To identify quantitative trait loci (QTLs) associated with culm length in Japanese japonica rice varieties, we conducted QTL analyses using a set of reciprocal backcrossed inbred lines (BILs) from crosses between Nipponbare and Koshihikari. We detected five QTLs in the two BILs that are involved in the culm-length difference between Nipponbare and Koshihikari. A QTL located on the short arm of chromosome 1, qCL1, was commonly detected near the simple sequence repeat (SSR) marker RM8068 in both BILs in three growing seasons. The Nipponbare allele of qCL1 shortened from 1.9 to 3.0cm of culm length. Substitution lines (SLs) of Koshihikari in which the QTL was replaced with the Nipponbare allele exhibited decreased lengths of lower internodes. qCL1 was mapped within about 2.6 Mbp in the region distal from SSR marker RM10132, suggesting qCL1 differed from the dwarf or semi-dwarf genes that have been previously reported. Japanese japonica rice landraces with Nipponbare alleles of DNA markers around qCL1 had significantly shorter culm length than other landraces. The results suggest that the novel allele for short culm length was originally distributed in Japanese rice landraces and has been used for introducing the semi-dwarf phenotype and improving plant architecture during practical breeding.

DOI： 10.1270/jsbbs.59.285

Towards the Understanding of Complex Traits in Rice: Substantially or Superficially? 査読

Toshio Yamamoto, Junichi Yonemaru, Masahiro Yano

DNA RESEARCH 16 ( 3 ) 141 - 154 2009年6月

担当区分：筆頭著者記述言語：英語出版者・発行元：OXFORD UNIV PRESS

Completion of the genome analysis followed by extensive comprehensive studies on a variety of genes and gene families of rice (Oryza sativa) resulted in rapid accumulation of information concerning the presence of many complex traits that are governed by a number of genes of distinct functions in this most important crop cultivated worldwide. The genetic and molecular biological dissection of many important rice phenotypes has contributed to our understanding of the complex nature of the genetic control with respect to these phenotypes. However, in spite of the considerable advances made in the field, details of genetic control remain largely unsolved, thereby hampering our exploitation of this useful information in the breeding of new rice cultivars. To further strengthen the field application of the genome science data of rice obtained so far, we need to develop more powerful genomics-assisted methods for rice breeding based on information derived from various quantitative trait loci (QTL) and related analyses. In this review, we describe recent progresses and outcomes in rice QTL analyses, problems associated with the application of the technology to rice breeding and their implications for the genetic study of other crops along with future perspectives of the relevant fields.

DOI： 10.1093/dnares/dsp006

Detection of a quantitative trait locus controlling carbon isotope discrimination and its contribution to stomatal conductance in japonica rice 査読

Toshiyuki Takai, Akihiro Ohsumi, Yumiko San-oh, Ma. Rebecca C. Laza, Motohiko Kondo, Toshio Yamamoto, Masahiro Yano

THEORETICAL AND APPLIED GENETICS 118 ( 7 ) 1401 - 1410 2009年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Increasing leaf photosynthesis offers a possible way to improve yield potential in rice (Oryza sativa L.). Carbon isotope discrimination (Delta(13)C) has potential as an indirect selection criterion. In this study, we searched for quantitative trait loci (QTLs) controlling Delta(13)C, and assessed their association with leaf photosynthesis. Substitution mapping by using chromosome segment substitution lines (CSSLs), that carry segments from the indica cultivar Kasalath in the genetic background of the japonica cultivar Koshihikari, identified genomic regions affecting Delta(13)C on chromosomes (Chr.) 2, 3, 6, 7, and 12. One of the CSSLs, SL208, in which most regions on Chr. 3 were substituted with Kasalath segments, showed higher leaf stomatal conductance for CO(2) (g (s)) and Delta(13)C than Koshihikari during the vegetative stage although leaf photosynthetic rate did not differ between them. These results suggest an association between Delta(13)C and g (s). To test this association, we performed a QTL analysis for Delta(13)C at vegetative and heading stages in an F(2) population derived from a cross between SL208 and Koshihikari. The results confirmed a QTL controlling Delta(13)C on the long arm of Chr. 3. By using a near-isogenic line specific to Hd6, we ruled out the possibility that variation in Delta(13)C was generated through the pleiotropic effect of heading date.

DOI： 10.1007/s00122-009-0990-9

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