Genes/QTLs for rice yield traits are reviewed in this chapter
Rice yield traits are complex agronomic traits governed by multiple genes called as quantitative traits loci (QTLs), which usually show a continuous phenotypic distribution in a segregating population derived from a cross of a pair of inbred lines. Most QTLs for yield traits show small genetic effect and are difficult to be identified. These minor QTLs play a vital role in regulating yield trait and are widely utilized in commercial rice varieties, so that fine-mapping and map-based cloning of these QTLs will be beneficial for breeding. Number of panicles per plant, number of grains per panicle, and grain weight are three component traits which are determined by tiller, panicle and grain development. Dissecting the genetic basis of these traits by QTL mapping can facilitate breeding high yield varieties. However, it is rather difficult to isolate these QTLs because each contributes little effect to yield traits, and the effect is strongly affected by the environment. In recent years, tremendous progress has been attained and many QTLs for rice yield traits have been isolated and functionally analyzed in detail, which provides new sights into the molecular mechanisms of the formation of rice yield traits. Meanwhile, mutant analysis has also functionally characterized many genes involved in yield traits because of the availability of rice genome and rice mutant collections. These studies greatly strengthen our understanding of regulatory mechanisms of these traits. In this chapter, we summarize the recent progress in the genetic and molecular mechanisms underlying rice yield traits and illustrate a strategy to develop varieties with higher yield potential.
2. Identification and validation of QTLs for rice yield traits
2.1. Identification of QTLs
QTL mapping of a target trait is defined as the chromosomal location and genetic characterization of QTLs for the trait through the association between genetic markers and phenotypic variations. To facilitate this mapping, development of mapping population, construction of linkage map and phenotypic evaluation are essential for QTL analysis.
Typically, mapping population includes F2 plants, doubled haploid lines (DHLs) and recombinant inbred lines (RILs). F2 population that carries the complete genetic information from the parents can be easily developed, but its phenotypic evaluation cannot be replicated . Due to the inherent homozygosity in the lines, both DHL and RIL populations can be planted repeatedly in different planting seasons and environment conditions as many times as necessary. DHL population is limitedly used in QTL mapping due to the difficulties in the plant regeneration from cultured anthers, especially for
Linkage map is composed of many linkage groups according to different chromosomes, which are constructed by genotyping using genome-wide polymorphic markers. DNA based molecular markers, such as restriction fragment length polymorphism (RFLP), simple sequence repeat (SSR), cleaved amplified polymorphic sequence (CAPS) and single nucleotide polymorphism (SNP), are widely applied in the construction of linkage map. Based on the complete genome-wide sequence of rice, it becomes easier to design genome-wide polymorphic markers and construct high density molecular linkage map .
Yield trait conditioned by QTLs usually varies continuously in a mapping population. Phenotypic values are difficult to be accurately measured due to environmental influences, especially for F2 population without replication. The precision of phenotypic data greatly affects the resolution of QTL mapping .
Thousands of QTLs for rice yield traits have been detected and are distributed throughout the whole genome while many of them are co-localized (http://www.gramene.org). We use one of our studies to illustrate the general process for the classical characteristics of QTLs (Figure 1). A RIL mapping population is developed from an
2.2. Validation of QTLs
Primary mapping cannot delimit an individual QTL in a precise location, so that further experiments are necessary to validate the biological function of target QTLs individually. Development of near isogenic lines (NILs) is an efficient strategy for QTL validation. NILs contain the segregated target QTL region in a homogeneous genetic background. In general, NILs are produced by consecutive backcrosses with a recurrent parent aided by molecular marker assisted selection (MAS). Only the plants carrying the target QTL in the recurrent parent background will be selected to further develop NILs. Many QTLs controlling rice yield traits have been validated by this classical method. However, successful backcross combining with MAS is laborious and time-consuming. During the process of developing Zhenshan 97B / Miyang 46 RIL population, we form a new method for developing NILs by screening residual heterozygous lines (RHLs). The RHLs should contain a heterozygous chromosomal segment at the target QTL region in a nearly homozygous genetic background  (Figure 1). Following MAS in a high density marker linkage map, a series of RHLs with overlapping segregated segments for the target QTL are selected from F7 RILs. This method has proven to be efficient, and several yield trait QTLs, such as
Introgression lines (ILs) and chromosome segment substitution lines (CSSLs), which are developed by backcrossing repeatedly with the recurrent parent, can also be used for QTL validation, fine-mapping and breeding superior rice varieties[17,18].
3. QTLs/genes for rice yield traits
3.1. QTLs/genes for tillering
Rice tillers are mainly composed of primary, secondary and tertiary tillers, which are shoot branches arising from the unelongated basal internodes. Tillering starts with the appearance of the fourth leaf from the main culm. Usually, the duration of tillering will last about 25-30 days. The number of panicles and yield potential are determined by panicle-bearing tillers, and grain yield are mainly contributed by primary and secondary tillers. Therefore, tiller number is considered a key component in determining rice yield. Some key genetic factors responsible for rice tillering have been molecularly characterized (Figure 2 and Table 1).
Rice tillering undergoes two major processes, the formation and outgrowth of tiller bud. Isolation and characterization of
||LOC_Os01g54270||Carotenoid cleavage dioxygenase 8||M|||
||LOC_Os03g10620||Alpha/beta-fold hydrolase superfamily protein||M|||
||LOC_Os04g46470||carotenoid cleavage dioxygenase||M|||
||LOC_Os06g06050||F-box leucine-trich repeat protein||M|||
||LOC_Os06g40780||GRAS family nuclear protein||M|||
||LOC_Os08g39890||Souamosa promoter binding protein-like 14||QTL||[27, 28]|
||LOC_Os07g05900||Zinc-finger nuclear transcription factor||QTL||[29, 30]|
||LOC_Os02g05980||Leucine-rich repeat receptor-like kinase||QTL|||
||LOC_Os01g61480||A bHLH transcription factor||M|||
||LOC_Os02g15950||Kelch repeat-containing F-box protein||M|||
||LOC_Os04g51000||Plant-specific transcription factor||M|||
||LOC_Os07g47330||Ethylene-responsive element-binding factor||M|||
||LOC_Os11g12740||Transporter of the peptide transporter family||M|||
||LOC_Os06g16370||Protein with a zinc finger domain||QTL|||
||LOC_Os07g15770||CCT domain protein||QTL|||
||LOC_Os08g07740||OsHAP3 subunit of a CCAAT-box binding protein||QTL||[63, 64]|
||LOC_Os10g32600||B-type response regulator||QTL||[65, 66]|
||LOC_Os09g26999||PEBP-like domain protein||QTL|||
||LOC_Os06g41850||Iindole-3-acetic acid (IAA)-glucose hydrolase||QTL|||
||LOC_Os02g14720||RING-type E3 ubiquitin ligase||QTL|||
||LOC_Os02g51320||Atypical bHLH protein||Hom*|||
||LOC_Os03g07510||Atypical bHLH protein||Hom*|||
||LOC_Os03g44500||Phosphatase with Kelch-like repeat domain||QTL||[43, 44]|
||LOC_Os04g55230||Protein with a tetratricopeptide repeat motif||M|||
||LOC_Os05g04740||Typical bHLH protein||Hom*|||
||LOC_Os05g06280||Kinesin 13 protein||M|||
||LOC_Os05g06660||Putative serine carboxypeptidase||QTL|||
||LOC_Os05g09520||Nuclear protein||QTL||[54, 55]|
||LOC_Os06g06530||ubiquitin-associated domain protein||M|||
||LOC_Os08g41940||Squamosa promoter-binding protein–like 16||QTL|||
Phytohormone pathways play a crucial role in controlling the outgrowth of tiller bud from leaf sheath. Plant hormones interact to regulate axillary bud outgrowth. It is well known that auxin maintains shoot apical dominance and inhibit axillary bud outgrowth, whereas cytokinins promote branches development . Strigolactones, as a new kind of terpenoid plant hormones, might act as the downstream of auxin to inhibit axillary bud outgrowth. Several genes involved in the synthesis and signaling pathway of strigolactones are isolated and functionally characterized through analyzing a serious of tillering dwarf mutants [20, 21].
Tiller number and angle are major determinants of rice plant architecture. New plant type known as ideal plant architecture (IPA) is proposed with reduced tiller number with almost no unproductive tillers to improve cultivar yield potential. A major QTL for IPA encoding SOUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (OsSPL14) has been cloned.
3.2. QTLs/genes regulating number of grains per panicle
Number of grains per panicle is an important agronomic trait for grain productivity, which is determined by the panicle formation. During the past two decades, many genes/QTLs controlling panicle development have been characterized (Figure 2 and Table 1). Rice panicle developed from a terminal inflorescence at the top of a stem contains panicle axis, primary and secondary branches, pedicel and spikelets. Pedicels arise from the primary and secondary branches and bear spikelets on the top. Panicles and the bearing spikelets on them directly determine the rice yield.
Inflorescence development determines the formation of rice panicle. Inflorescence meristem generates primary and secondary branches meristems, and subsequent spikelet meristems. Several genes involved in the formation of inflorescence branch and spikelet meristems are identified through mutant analysis.
Rice panicle size is largely determined by the number and length of primary and secondary branches.
Rice panicle architecture is mainly determined by the arrangement of primary and secondary branches and grain density. Erect panicle is an important agronomic trait closely related to grain yield.
Cytokinins regulate number of spikelets per panicle. A major QTL,
3.3. QTLs/genes controlling grain weight
Rice grain is closely enclosed by a hull which is composed of one palea, lemma, rachilla and two sterile lemmas. A brown rice mainly consists of bran, endosperm and embryo. During the process of grain filling, endosperm cells expand and accumulate a massive amount of nutrients, mainly starch. Rice grain weight is largely determined by the endosperm size. Dozens of genes/QTLs involved in rice grain weight have been isolated and molecularly characterized (Figure 2 and Table 1).
Given that each grain in a rice panicle can be fully filled, grain weight is determined by grain size, which can be measured with grain length, width and thickness.
Four QTLs conditioning grain width,
Grain thickness largely depends on the ability of grain filling.
4. QTLs/genes for rice yield-related traits
Plant height and heading date are two important agronomic traits closely related to rice yield. The Green Revolution has made a tremendous contribution to solve the global food crisis, and this mark achievement in rice is caused by the application of
Genes/QTLs controlling heading date usually prolong the duration of panicle differentiation to produce more spikelets per panicle and enhance grain yield potential.
5. Future perspectives
As mentioned above, cloning and functional characterization of genes/QTLs have greatly strengthened our understanding in the genetic and molecular mechanisms underlying rice yield traits, which has facilitated the breeding efforts for higher yield potential varieties. Pyramiding of favorable genes/QTLs has become an efficient strategy in rice genetic improvement and is widely adopted by rice breeders. For instance, combination of
Although tremendous progress has been made in the studies of rice yield trait, there is still a long way to clearly elucidate the molecular mechanisms responsible for the formation of rice yield traits. Almost all the rice yield traits including number of panicles per plant, number of grains per panicle and grain weight exhibit comprehensive and continuous variations in the genetic population or among the commercial varieties, typically due to the function of multiple genes called as QTLs. According to the Gramene database, thousands of QTLs conditioning rice yield traits have been detected by QTL mapping and majorities of them are minor QTLs with small genetic effect, which are difficult to be identified through mutant analysis. However, minor QTLs may participate in different molecular pathways to regulate rice yield traits and play a vital role in improving yield potential. During the long domestication process, these minor QTLs have been selected and combined relying on the breeders’ experience to develop cultivated varieties. Therefore, more efforts are necessary to isolate minor QTLs and elucidate the functional mechanisms in the future.
Natural variation exists widely in the genes/QTLs, resulting in many alleles for each gene/QTL. For example,
This work was supported by the Chinese High-Yielding Transgenic Program (2013ZX08001004-006), the Chinese 863 Program (2012AA101102), and the Zhejiang Provincial Natural Science Foundation (Y3110394). We are grateful to Dr. Jie-Yun Zhuang at China National Rice Research Institute for valuable discussions and suggestions.
Khush GS: Green revolution: the way forward. Nat Rev Genet2001, 2:815-822.
Cheng SH, Zhuang JY, Fan YY, Du JH, Cao LY: Progress in research and development on hybrid rice: a super-domesticate in China. Ann Bot2007, 100:959-966.
Jeon JS, Jung KH, Kim HB, Suh JP, Khush GS: Genetic and Molecular Insights into the Enhancement of Rice Yield Potential. JOURNAL OF PLANT BIOLOGY2011, 54:1-9.
Xing Y, Zhang Q: Genetic and molecular bases of rice yield. Annu Rev Plant Biol2010, 61:421-442.
Ying JZ, Gao JP, Shan JX, Zhu MZ, Shi M, Lin HX: Dissecting the genetic basis of extremely large grain shape in rice cultivar 'JZ1560'. J Genet Genomics2012, 39:325-333.
Lin YJ, Zhang Q: Optimising the tissue culture conditions for high efficiency transformation of indica rice. Plant Cell Rep2005, 23:540-547.
Nishimura A, Aichi I, Matsuoka M: A protocol for Agrobacterium-mediated transformation in rice. Nat Protoc2006, 1:2796-2802.
Lee SY, Ahn JH, Cha YS, Yun DW, Lee MC, Ko JC, Lee KS, Eun MY: Mapping of quantitative trait loci for salt tolerance at the seedling stage in rice. Mol Cells2006, 21:192-196.
Andaya VC, Mackill DJ: QTLs conferring cold tolerance at the booting stage of rice using recombinant inbred lines from a japonica x indica cross. Theor Appl Genet2003, 106:1084-1090.
Xing Z, Tan F, Hua P, Sun L, Xu G, Zhang Q: Characterization of the main effects, epistatic effects and their environmental interactions of QTLs on the genetic basis of yield traits in rice. Theor Appl Genet2002, 105:248-257.
Zhuang JY, Fan YY, Rao ZM, Wu JL, Xia YW, Zheng KL: Analysis on additive effects and additive-by-additive epistatic effects of QTLs for yield traits in a recombinant inbred line population of rice. Theor Appl Genet2002, 105:1137-1145.
Wissuwa M, Ismail AM, Yanagihara S: Effects of zinc deficiency on rice growth and genetic factors contributing to tolerance. Plant Physiol2006, 142:731-741.
Onishi K, Horiuchi Y, Ishigoh-Oka N, Takagi K, Ichikawa N, Maruoka M, Sano Y: A QTL cluster for plant architecture and its ecological significance in Asian wild rice. BREEDING SCIENCE2007, 57:7-16.
Project IRGS: The map-based sequence of the rice genome. Nature2005, 436:793-800.
Bai X, Wu B, Xing Y: Yield-related QTLs and their applications in rice genetic improvement. J Integr Plant Biol2012, 54:300-311.
Shao G, Tang S, Luo J, Jiao G, Wei X, Tang A, Wu J, Zhuang J, Hu P: Mapping of qGL7-2, a grain length QTL on chromosome 7 of rice. J Genet Genomics2010, 37:523-531.
Hao W, Zhu MZ, Gao JP, Sun SY, Lin HX: Identification of quantitative trait loci for rice quality in a population of chromosome segment substitution lines. J Integr Plant Biol2009, 51:500-512.
mai I, Kimball J, Conway B, Yeater K, McCouch S, McClung A: Validation of yield-enhancing quantitative trait loci from a low-yielding wild ancestor of rice. Mol Breeding2013:1-20.
Li X, Qian Q, Fu Z, Wang Y, Xiong G, Zeng D, Wang X, Liu X, Teng S, Hiroshi F, et al.: Control of tillering in rice. Nature2003, 422:618-621.
Gomez-Roldan V, Fermas S, Brewer PB, Puech-Pages V, Dun EA, Pillot JP, Letisse F, Matusova R, Danoun S, Portais JC, et al.: Strigolactone inhibition of shoot branching. Nature2008, 455:189-194.
Umehara M, Hanada A, Yoshida S, Akiyama K, Arite T, Takeda-Kamiya N, Magome H, Kamiya Y, Shirasu K, Yoneyama K, et al.: Inhibition of shoot branching by new terpenoid plant hormones. Nature2008, 455:195-200.
Zou J, Zhang S, Zhang W, Li G, Chen Z, Zhai W, Zhao X, Pan X, Xie Q, Zhu L: The rice HIGH-TILLERING DWARF1encoding an ortholog of Arabidopsis MAX3is required for negative regulation of the outgrowth of axillary buds. Plant J2006, 48:687-698.
Arite T, Iwata H, Ohshima K, Maekawa M, Nakajima M, Kojima M, Sakakibara H, Kyozuka J: DWARF10, an RMS1/ MAX4/ DAD1ortholog, controls lateral bud outgrowth in rice. Plant J2007, 51:1019-1029.
Lin H, Wang R, Qian Q, Yan M, Meng X, Fu Z, Yan C, Jiang B, Su Z, Li J, et al.: DWARF27, an iron-containing protein required for the biosynthesis of strigolactones, regulates rice tiller bud outgrowth. Plant Cell2009, 21:1512-1525.
Ishikawa S, Maekawa M, Arite T, Onishi K, Takamure I, Kyozuka J: Suppression of tiller bud activity in tillering dwarf mutants of rice. Plant Cell Physiol2005, 46:79-86.
Arite T, Umehara M, Ishikawa S, Hanada A, Maekawa M, Yamaguchi S, Kyozuka J: d14, a strigolactone-insensitive mutant of rice, shows an accelerated outgrowth of tillers. Plant Cell Physiol2009, 50:1416-1424.
Miura K, Ikeda M, Matsubara A, Song XJ, Ito M, Asano K, Matsuoka M, Kitano H, Ashikari M: OsSPL14promotes panicle branching and higher grain productivity in rice. Nat Genet2010, 42:545-549.
Jiao Y, Wang Y, Xue D, Wang J, Yan M, Liu G, Dong G, Zeng D, Lu Z, Zhu X, et al.: Regulation of OsSPL14by OsmiR156 defines ideal plant architecture in rice. Nat Genet2010, 42:541-544.
Jin J, Huang W, Gao JP, Yang J, Shi M, Zhu MZ, Luo D, Lin HX: Genetic control of rice plant architecture under domestication. Nat Genet2008, 40:1365-1369.
Tan L, Li X, Liu F, Sun X, Li C, Zhu Z, Fu Y, Cai H, Wang X, Xie D, et al.: Control of a key transition from prostrate to erect growth in rice domestication. Nat Genet2008, 40:1360-1364.
Zha X, Luo X, Qian X, He G, Yang M, Li Y, Yang J: Over-expression of the rice LRK1gene improves quantitative yield components. Plant Biotechnol J2009, 7:611-620.
Komatsu M, Maekawa M, Shimamoto K, Kyozuka J: The LAX1and FRIZZY PANICLE 2genes determine the inflorescence architecture of rice by controlling rachis-branch and spikelet development. Dev Biol2001, 231:364-373.
Komatsu M, Chujo A, Nagato Y, Shimamoto K, Kyozuka J: FRIZZY PANICLEis required to prevent the formation of axillary meristems and to establish floral meristem identity in rice spikelets. Development2003, 130:3841-3850.
Ikeda K, Ito M, Nagasawa N, Kyozuka J, Nagato Y: Rice ABERRANT PANICLE ORGANIZATION 1, encoding an F-box protein, regulates meristem fate. Plant J2007, 51:1030-1040.
Ikeda-Kawakatsu K, Maekawa M, Izawa T, Itoh J, Nagato Y: ABERRANT PANICLE ORGANIZATION 2/ RFL, the rice ortholog of Arabidopsis LEAFY, suppresses the transition from inflorescence meristem to floral meristem through interaction with APO1. Plant J2012, 69:168-180.
Li S, Qian Q, Fu Z, Zeng D, Meng X, Kyozuka J, Maekawa M, Zhu X, Zhang J, Li J, et al.: Short panicle1encodes a putative PTR family transporter and determines rice panicle size. Plant J2009, 58:592-605.
Huang X, Qian Q, Liu Z, Sun H, He S, Luo D, Xia G, Chu C, Li J, Fu X: Natural variation at the DEP1locus enhances grain yield in rice. Nat Genet2009, 41:494-497.
Li F, Liu W, Tang J, Chen J, Tong H, Hu B, Li C, Fang J, Chen M, Chu C: Rice DENSE AND ERECT PANICLE 2is essential for determining panicle outgrowth and elongation. Cell Res2010, 20:838-849.
Ashikari M, Sakakibara H, Lin S, Yamamoto T, Takashi T, Nishimura A, Angeles ER, Qian Q, Kitano H, Matsuoka M: Cytokinin oxidase regulates rice grain production. Science2005, 309:741-745.
Kurakawa T, Ueda N, Maekawa M, Kobayashi K, Kojima M, Nagato Y, Sakakibara H, Kyozuka J: Direct control of shoot meristem activity by a cytokinin-activating enzyme. Nature2007, 445:652-655.
Li M, Tang D, Wang K, Wu X, Lu L, Yu H, Gu M, Yan C, Cheng Z: Mutations in the F-box gene LARGER PANICLEimprove the panicle architecture and enhance the grain yield in rice. Plant Biotechnol J2011, 9:1002-1013.
Mao H, Sun S, Yao J, Wang C, Yu S, Xu C, Li X, Zhang Q: Linking differential domain functions of the GS3 protein to natural variation of grain size in rice. Proc Natl Acad Sci U S A2010, 107:19579-19584.
Zhang X, Wang J, Huang J, Lan H, Wang C, Yin C, Wu Y, Tang H, Qian Q, Li J, et al.: Rare allele of OsPPKL1associated with grain length causes extra-large grain and a significant yield increase in rice. Proc Natl Acad Sci U S A2012, 109:21534-21539.
Qi P, Lin YS, Song XJ, Shen JB, Huang W, Shan JX, Zhu MZ, Jiang L, Gao JP, Lin HX: The novel quantitative trait locus GL3.1controls rice grain size and yield by regulating Cyclin-T1;3. Cell Res2012, 22:1666-1680.
Ishimaru K, Hirotsu N, Madoka Y, Murakami N, Hara N, Onodera H, Kashiwagi T, Ujiie K, Shimizu B, Onishi A, et al.: Loss of function of the IAA-glucose hydrolase gene TGW6enhances rice grain weight and increases yield. Nat Genet2013, 45:707-711.
Kitagawa K, Kurinami S, Oki K, Abe Y, Ando T, Kono I, Yano M, Kitano H, Iwasaki Y: A novel kinesin 13 protein regulating rice seed length. Plant Cell Physiol2010, 51:1315-1329.
Segami S, Kono I, Ando T, Yano M, Kitano H, Miura K, Iwasaki Y: Small and round seed 5gene encodes alpha-tubulin regulating seed cell elongation in rice - Springer. Rice2012, 5:4.
Heang D, Sassa H: Antagonistic actions of HLH/bHLH proteins are involved in grain length and weight in rice. PLoS One2012, 7:e31325.
Heang D, Sassa H: An atypical bHLH protein encoded by POSITIVE REGULATOR OF GRAIN LENGTH 2is involved in controlling grain length and weight of rice through interaction with a typical bHLH protein APG. Breed Sci2012, 62:133-141.
Yamamuro C, Ihara Y, Wu X, Noguchi T, Fujioka S, Takatsuto S, Ashikari M, Kitano H, Matsuoka M: Loss of function of a rice brassinosteroid insensitive1 homolog prevents internode elongation and bending of the lamina joint. Plant Cell2000, 12:1591-1606.
Mori M, Nomura T, Ooka H, Ishizaka M, Yokota T, Sugimoto K, Okabe K, Kajiwara H, Satoh K, Yamamoto K, et al.: Isolation and characterization of a rice dwarf mutant with a defect in brassinosteroid biosynthesis. Plant Physiol2002, 130:1152-1161.
Nakagawa H, Tanaka A, Tanabata T, Ohtake M, Fujioka S, Nakamura H, Ichikawa H, Mori M: Short grain1decreases organ elongation and brassinosteroid response in rice. Plant Physiol2012, 158:1208-1219.
Song XJ, Huang W, Shi M, Zhu MZ, Lin HX: A QTL for rice grain width and weight encodes a previously unknown RING-type E3 ubiquitin ligase. Nat Genet2007, 39:623-630.
Weng J, Gu S, Wan X, Gao H, Guo T, Su N, Lei C, Zhang X, Cheng Z, Guo X, et al.: Isolation and initial characterization of GW5, a major QTL associated with rice grain width and weight. Cell Res2008, 18:1199-1209.
Shomura A, Izawa T, Ebana K, Ebitani T, Kanegae H, Konishi S, Yano M: Deletion in a gene associated with grain size increased yields during rice domestication. Nat Genet2008, 40:1023-1028.
Li Y, Fan C, Xing Y, Jiang Y, Luo L, Sun L, Shao D, Xu C, Li X, Xiao J, et al.: Natural variation in GS5plays an important role in regulating grain size and yield in rice. Nat Genet2011, 43:1266-1269.
57. Wang S, Wu K, Yuan Q, Liu X, Liu Z, Lin X, Zeng R, Zhu H, Dong G, Qian Q, et al.: Control of grain size, shape and quality by OsSPL16in rice. Nat Genet2012, 44:950-954.
Wang E, Wang J, Zhu X, Hao W, Wang L, Li Q, Zhang L, He W, Lu B, Lin H, et al.: Control of rice grain-filling and yield by a gene with a potential signature of domestication. Nat Genet2008, 40:1370-1374.
Li J, Chu H, Zhang Y, Mou T, Wu C, Zhang Q, Xu J: The rice HGWgene encodes a ubiquitin-associated (UBA) domain protein that regulates heading date and grain weight. PLoS One2012, 7:e34231.
She KC, Kusano H, Koizumi K, Yamakawa H, Hakata M, Imamura T, Fukuda M, Naito N, Tsurumaki Y, Yaeshima M, et al.: A novel factor FLOURY ENDOSPERM2is involved in regulation of rice grain size and starch quality. Plant Cell2010, 22:3280-3294.
Sasaki A, Ashikari M, Ueguchi-Tanaka M, Itoh H, Nishimura A, Swapan D, Ishiyama K, Saito T, Kobayashi M, Khush GS, et al.: Green revolution: a mutant gibberellin-synthesis gene in rice. Nature2002, 416:701-702.
Xue W, Xing Y, Weng X, Zhao Y, Tang W, Wang L, Zhou H, Yu S, Xu C, Li X, et al.: Natural variation in Ghd7is an important regulator of heading date and yield potential in rice. Nat Genet2008, 40:761-767.
Wei X, Xu J, Guo H, Jiang L, Chen S, Yu C, Zhou Z, Hu P, Zhai H, Wan J: DTH8suppresses flowering in rice, influencing plant height and yield potential simultaneously. Plant Physiol2010, 153:1747-1758.
Yan WH, Wang P, Chen HX, Zhou HJ, Li QP, Wang CR, Ding ZH, Zhang YS, Yu SB, Xing YZ, et al.: A major QTL, Ghd8, plays pleiotropic roles in regulating grain productivity, plant height, and heading date in rice. Mol Plant2011, 4:319-330.
Endo-Higashi N, Izawa T: Flowering time genes Heading date 1and Early heading date 1together control panicle development in rice. Plant Cell Physiol2011, 52:1083-1094.
Doi K, Izawa T, Fuse T, Yamanouchi U, Kubo T, Shimatani Z, Yano M, Yoshimura A: Ehd1, a B-type response regulator in rice, confers short-day promotion of flowering and controls FT-like gene expression independently of Hd1. Genes Dev2004, 18:926-936.
Zhang ZH, Wang K, Guo L, Zhu YJ, Fan YY, Cheng SH, Zhuang JY: Pleiotropism of the photoperiod-insensitive allele of Hd1on heading date, plant height and yield traits in rice. PLoS One2012, 7:e52538.