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10 November 2021, Volume 35 Issue 6 Previous Issue    Next Issue
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综述与专论
研究报告

研究报告


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综述与专论

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Breeding Practice and Prospect of Rice Male Sterile Lines with High Harvest Index Wenbang TANG, Fan LI, Guilian ZHANG, Huabing DENG, Feng WANG, Xingquan MING 2021, 35(6): 519-528.  DOI: 10.16819/j.1001-7216.2021.210103 Abstract ( )   HTML ( )   PDF (15154KB) ( )   Given the current situation of hybrid rice breeding, we reviewed the breeding history of rice sterile lines, summarized the difficulties and main problems of rice sterile line breeding in China, emphatically introduced eight two-line male sterile lines with small grains, including Zhuo 201S, Zhuo 234S, Zhan 998S and Nan 3502S, etc, which were bred by Hunan Agricultural University, and featured with strong and dwarf plant type, small leaf angles, medium biological yield, strong tillering ability, high productive tiller rates, strong stem and high lodging resistance, good outcrossing characteristics, high seed setting rates and high harvest indexes. A series of high-yield and high-quality hybrid rice combinations Zhuoliangyou 0985, Zhuoliangyou 141, Nanliangyou 1998 and other combinations showed high and stable yield, high harvest index, wide adaptability, high yield and good seed quality. Through a series of breeding practices of male sterile lines with high harvest index, taking Zhan 998S as an example, the biological characteristics of male sterile lines with high harvest index were summarized, and the breeding strategies of high harvest index male sterile lines in the future were discussed.

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Creation and Application of the Breeding Theory Based on Rice Core Germplasm Shaochuan ZHOU, Wei KE, Ruowei MIAO, Hong LI, Daoqiang HUANG, Chongrong WANG 2021, 35(6): 529-534.  DOI: 10.16819/j.1001-7216.2021.210801 Abstract ( )   HTML ( )   PDF (9970KB) ( )   For the seamless connection between rice breeding and rice germplasm resources, and the integration of conventional breeding technology and advanced applicable technology, our team has established rice core germplasm breeding theory and material collections. The rice core germplasm breeding theory includes the conception of rice core germplasm, corresponding hypothesis of ideal gene system and groundbreaking rice varieties, creation of the ideal model, comprehensive planning of background selection and foreground selection, DNA block of biological significances, data cloud of genotypes and phenotypes of rice core germplasm, research on comprehensive rice breeding by advanced and applicable technology, heterosis utilization of rice core germplasm. Huanghuazhan, Meixiangzhan and Huazhan core germplasm breeding materials were created, as well as the variety of Huanghuazhan with the largest growing area as indica rice in China, and the variety of Meixiangzhan 2 with excellent eating quality in China, the restore line of Huazhan with excellent combining ability in rice breeding history on the basis of rice core germplasm breeding theory.

研究报告

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Cloning and Functional Analysis of Rice Tillering Regulatory Gene HTD3 Xianmei WU, Sanfeng LI, Ping HU, Rui HE, Ran JIAO, Yijian MAO, Caolin LU, Juan HU, Han LIN, Rongliang WU, Xudong ZHU, Yuchun RAO, Yuexing WANG 2021, 35(6): 535-542.  DOI: 10.16819/j.1001-7216.2021. 210205 Abstract ( )   HTML ( )   PDF (17826KB) ( )   【Objective】Cloning of rice tiller-related genes lays a theoretical basis and provides beneficial genetic resources for constructing ideal plant-type rice and increasing grain yield.【Method】We compared phenotypes and main agronomic traits between the mutant htd3 (high-tillering dwarf 3) and its wild type under conventional field planting conditions, used map-based cloning method to clone candidate genes, analyzed the expression levels of HTD3, SL and ABA-related genes by fluorescence quantitative real-time PCR. Sequencing comparison was performed to analyze the natural variation of HTD3 in 147 germplasm resources.【Result】Compared with the wild type, the axillay bud of the mutant htd3 grow faster, the number of tillers and effective panicles were significantly increased, the plant height, the number of primary rachis branches and grains per panicle were significantly decreased, and the seed setting rate and 1000-grain weight were not significantly changed. Genetic analysis indicated that the high-tillering trait of htd3 was controlled by single recessive nuclear gene, which was mapped to a 63.5 kb region between the marker CM8 and CM10 on chromosome 12, and the complementary transgenic experiment proved that LOC_Os12g21710 was the gene controlling the high-tillering phenotype. HTD3 is constitutively expressed in wild-type and mutant, and the mutation of this gene could up-regulate the expression level of some stratolactones and ABA-related genes. The natural variation of G2674A in the HTD3 coding region in rice varieties significantly increase the number of tillers.【Conclusion】HTD3 is a new allele of the recently reported T20/MIT1 gene. The HTD3 mutation leads to the phenotype of moderate increase in tillers and slightly shorter plant height in rice, which has great application potential in cultivating ideal plant type rice and high-yield breeding.

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Distribution of Grain Shape Related Genes in Rice Big Grain Germplasm BG1 and Elite Restorer Line Huazhan and Development of Relevant Functional Markers Ke GONG, Pao XUE, Xiaoxia WEN, Feifei LIAO, Bin SUN, Zequn PENG, Shihua CHENG, Liyong CAO, Yingxin ZHANG, Weixun WU, Lianping SUN, Xiaodeng ZHAN 2021, 35(6): 543-553.  DOI: 10.16819/j.1001-7216.2021.201211 Abstract ( )   HTML ( )   PDF (32401KB) ( )   【Objective】The exploration and utilization of specific germplasm resources are one of the important means of rice breeding with high quality and high yield. Identifying the allelic variation types of some grain shape genes carried by Big Grain 1 (BG1) and Huazhan, a high quality restorer line widely used in rice breeding, and developing functional markers of corresponding genes are helpful to speed up the application of grain shape genes in rice breeding and improve the efficiency of accurate improvement of grain shape in rice.【Method】The target fragments of nine major grain shape genes (GS3, qLGY3, qGL3, GW2, GW8, GW5, TGW3, TGW6, GS9) in BG1 and Huazhan were sequenced and analyzed. According to the sequencing results of GW2, GS3, qGL3, TGW3, TGW6, qLGY3, GW8 and GW5, a functional marker for genotyping was developed.【Result】Compared with Nipponbare, 5 of the 9 major grain shape genes detected in BG1 showed functional deletion (gs3, GW8, gw2, tgw3, tgw6), 1 rare allele variation (qgl3) and 1 exon variable shear (qlgy3); Compared with Nipponbare, Huazhan had differences in 3 of the 9 major grain shape genes (gs3, GW8 and GW5). According to the sequencing results, the functional markers of GW2, GS3, QGL3, TGW3, TGW6, QLGY3, GW8 and GW5 were developed and 15 rice germplasm were used for detection. In the detection results, in addition to the marker tgw6-del of TGW6, which can only be used to identify whether there is allelic variation tgw6 of functional deletion type, the other 7 markers can accurately identify genotype. There was sequence variation of GS9 among the tested materials, which did not affect the change of grain shape. According to the above sequencing results, the functional markers of GW2, GS3, qGL3, TGW3, TGW6, qLGY3, GW8 and GW5 were developed and detected by 15 rice germplasms. Except for the marker TGW6-Del for TGW6, which can only be used to identify the allelic variant tgw6, a functional deletion type, the other seven markers can be genotyped accurately.【Conclusion】Compared with Nipponbare, the genes gs3, qgl3, qlgy3, tgw3, GW8 and tgw6 that regulate grain length in extra-large grain germplasm BG1 may have complex interaction pathways rather than simple effect accumulation, and the grain width may be the cumulative effect of gw2 and GW8. The slender grain shape of high quality restorer line Huazhan may be caused by the interaction effect of gs3, GW5 and GW8. The functional markers developed can be used in rice molecular marker-assisted breeding.

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Transcriptome Analysis of Hormone Signal Transduction and Glutathione Metabolic Pathway in Rice Seeds at Germination Stage Huan CUI, Qiaoli GAO, Lixin LUO, Jing YANG, Chun CHEN, Tao GUO, Yongzhu LIU, Yongxiang HUANG, Hui WANG, Zhiqiang CHEN, Wuming XIAO 2021, 35(6): 554-564.  DOI: 10.16819/j.1001-7216.2021.200915 Abstract ( )   HTML ( )   PDF (61405KB) ( )   【Objective】By using transcriptome sequencing technology, we explored the regulation mechanism of hormone signal transduction and redox balance inside cells during rice germination, as a way to increase the understanding of and construct the complex regulatory network of germination. At the same time, mining the genes that regulate seed germination could lay a theoretical basis for direct-seeded rice breeding.【Method】Dynamic transcriptome sequencing analysis was performed using seeds at 0, 24, and 48 hours after imbibition as materials. Differentially expressed genes (DEGs) were screened with the threshold of Fold Change≥2 and False Discovery Rate≤ 0.05. Gene Ontology and KEGG Pathway databases were used to analyze and annotate the DEGs at different stages of germination and real-time quantitative PCR was conducted to verify the sequencing results. Finally, the protein interaction network of DEGs was analyzed using the String protein interaction database under the threshold of combined_score≥0.9.【Result】8719 DEGs were identified in the early stage of seed germination, but only 3480 DEGs in the late stage of germination. The results of GO and KEGG enrichment analysis showed that the DEGs related to hormone signal transduction were mainly induced in the early stage, especially the GH3 (Gretchen Hagen 3) family genes in the auxin signal transduction pathway were all significantly induced after imbibition. While the DEGs involved in the glutathione metabolism pathway were more active during the late germination period, and the glutathione-S-transferase genes were the most enriched in this pathway. In addition, two isocitrate dehydrogenase (ICDH) genes were significantly induced throughout the germination process. According to protein interaction prediction, the two ICDH genes may interact with the GH3 family genes.【Conclusion】The GH3 family genes in the AUX signal transduction pathway may play an important role in attenuating the AUX signal and reducing the AUX activity in the early stage of seed germination. Their high expression levels reduce the regulatory effect of auxin on seed dormancy and promote seed germination. In the glutathione metabolism pathway, GST genes may play a major role in resistance to cell oxidative stress in the late stage of seed germination. In addition, the interaction between GH3 and ICDH family genes during the germination process may have important significance in realizing the tandem effect of hormone transduction pathway and glutathione metabolism pathway and co-regulating seed germination.

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Research on the Mechanisim of OsPT4 Regulating the Accumulation and Utilization of Nitrogen and Phosphorus in Rice Yafei SUN, Ke SONG, Qin QIN, Lijuan SUN, Yong XUE 2021, 35(6): 565-572.  DOI: 10.16819/j.1001-7216.2021.200803 Abstract ( )   HTML ( )   PDF (37636KB) ( )   【Objective】 The phosphate (Pi) transporter, OsPT4, is a member of the Pht1 family of rice, responsible for Pi uptake and transportation. It is important to explore the effect of OsPT4 overexpression on nitrogen (N) and phosphorous (P) accumulation and utilization in rice under different Pi conditions and its mechanism. 【Method】The OsPT4-overexpressing lines with Nipponbare background were used as material. Through the hydroponic and pot-cultivated experiments with (+Pi) or without Pi (-Pi) supply, the relative expression of OsPT4 in different tissues during reproductive growth stage was detected. The N and P concentrations in different tissues (leaf blade, leaf sheath, stem, rice hull, panicle axis and brown rice) under different Pi treatments were also measured. In addition, the Pi absorption rate and N/P use efficiency were calculated, and the plant height, yield per plant, 1000-grain weight and seed setting rate were analyzed. 【Result】The relative expression of OsPT4 was higher in rice roots during reproductive growth stage. Overexpression of OsPT4 increased the total P concentration in rice flag leaf blade, leaf sheaths, stems, rice hull, panicle axis and brown rice to varying degrees, and significantly improved the Pi absorption and use efficiency under different Pi regimes. Meanwhile, OsPT4 overexpression could significantly increase the yield per plant, 1000-grain weight and seed setting rate in +Pi and -Pi soils. In addition, the overexpression of OsPT4 also increased the total N concentration in unfilled rice hull and brown rice by 16.8% and 19.8%, and the N use efficiency by 6.6% under Pi-deficiency. 【Conclusion】The overexpression of OsPT4 not only promotes the Pi uptake and use efficiency, but also facilitates the physiology N use efficiency in different Pi conditions.

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Comprehensive Evaluation and QTL Analysis for Flag Leaf Traits Using a Backcross Population in Rice Jie LI, Rongrong TIAN, Tianliang BAI, Chunyan ZHU, Jiawei SONG, Lei TIAN, Shuaiguo MA, Jiandong LÜ, Hui HU, Zhenyu WANG, Chengke LUO, Yinxia ZHANG, Peifu LI 2021, 35(6): 573-585.  DOI: 10.16819/j.1001-7216.2021.210110 Abstract ( )   HTML ( )   PDF (38465KB) ( )   【Objective】In order to clarify the correlations between flag leaf-related traits and their relationships with six agronomic traits, a comprehensive evaluation of flag leaf traits was made. The identification of QTLs associated with flag leaf traits will lay a foundation for fine mapping and cloning of the functional genes underlying rice flag leaf-related traits, which is helpful to breed elite cultivars with excellent flag leaf traits. 【Method】A backcross population with two generations derived from an elite japonica rice cultivar Koshihikari (recipient) and a Portuguese rice landrace Bertone (donor) was used as plant materials. The genetic linkage maps were constructed by using SSR markers with the BC3F1 population. Several parameters including flag leaf SPAD, flag leaf length, flag leaf width, length to width ratio of flag leaf as well as flag leaf area were measured in the parental varieties and BC3F2 population. In order to analyze the relationship between D value and the six agronomic traits, membership functions and the index weight method were used to comprehensively evaluate the flag leaf traits of these 260 BC3F2 lines. Single-point analysis (SPA) and interval mapping (IM) were used to identify QTLs for traits related to flag leaf in rice.【Result】After the flag leaf was fully expanded, the flag leaf SPAD values of the two parents showed a dynamic change, increasing at first and reduced subsequently. The five flag leaf-related traits of the BC3F2 population exhibited diverse phenotypic variations, whose overall performance resembled the recurrent parent (Koshihikari). The results revealed that four morphological traits of flag leaf were significantly correlated with each other, while there were no significant correlations with flag leaf SPAD. Using principal component analysis (PCA) and stepwise regression analysis, flag leaf width, flag leaf SPAD, flag leaf length and flag leaf area were selected as the key indexes of D value out of the flag leaf comprehensive evaluation. The results showed that except for tiller number and effective panicle number, the other four traits including plant height, panicle length, basal culm thickness and grain yield per plant were all significantly higher in lines with a higher D value than that in lines with a small D value. A total of 18 QTLs were detected, which were located on chromosomes 1, 4, 7 and 8 with phenotypic variation explained ranging from 4.00% to 28.00% (SPA) and 3.41% to 27.00% (IM), respectively. Except for qFLSPAD1, the other 17 QTLs showed synergistic effect from Bertone alleles. Moreover, a QTL cluster was found in the RM22720–RM404 interval on chromosome 8, containing six major QTLs(qFLL8.1, qFLL8.2, qFLA8.1, qFLA8.2, qD8.1 and qD8.2). 【Conclusion】Flag leaf width, flag leaf SPAD, flag leaf length and flag leaf area were the important indicators that affect the comprehensive evaluation of flag leaf. The flag leaf traits were significantly or extremely significantly positively correlated with the yield per plant. Here we identified 18 QTLs for flag leaf traits and a QTL cluster detected in the RM22720–RM404 interval on chromosome 8, which is an important chromosomal region affecting flag leaf-related traits.

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Effects of Improved Crop Management on Growth Characteristic of Root and Shoot, Water and Nitrogen Use Efficiency, and Grain Yield in Rice Guang CHU, Ran XU, Song CHEN, Chunmei XU, Yuanhui LIU, Xiufu ZHANG, Danying WANG 2021, 35(6): 586-594.  DOI: 10.16819/j.1001-7216.2021.201213 Abstract ( )   HTML ( )   PDF (15307KB) ( )   【Objective】This study aims to determine if an improved root system under improved crop management (ICM) could promote shoot growth, physiological processes, and consequently contribute to an increase in grain yield and nitrogen and/or water use efficiency.【Method】An indica/japonica hybrid rice cultivar Yongyou 1540 was field grown. at zero nitrogen level under local farmers’ practice (LFP) and ICM in Hangzhou in 2018 and 2019. 【Results】The grain yield was 11.5 t/hm2 under ICM, insignificantly different from that under ICM and LFP. Compared to LFP, ICM significantly increased both nitrogen use efficiency (NUE) and water use efficiency (WUE), and improved several root morphological and physiological traits. For instance, ICM significantly reduced root dry weight and root-shoot ratio, increased root dry weight in 10-20 cm soil layer, specific root length, active absorbing surface area at heading and mid-grain filling period, and root oxidation activity and concentration of Z+ZR in root-bleeding sap at mid- and late-grain filling periods compared to LFP. Furthermore, ICM significantly increased flag leaf photosynthetic rate, concentration of Z+ZR in leaves, activities of enzymes involved in sucrose-to-starch conversion in grains at mid- and late-grain filling periods compared to LFP.【Conclusion】Improved root morphological and physiological traits under ICM promote shoot growth, physiological processes, and consequently, contribute to an increases in water and nitrogen use efficiency.

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Effects of Seeding Quantity and Transplanting Machine Type on Nitrogen Utilization and Yield of Mechanically transplanted Rice in Different Seedling Raising Ways Yuanyuan SUN, Qiao ZHANG, Yongjian SUN, Yuan TANG, Changchun GUO, Fangyan LIU, Yunxia WU, Zhiyuan YANG, jun MA 2021, 35(6): 595-605.  DOI: 10.16819/j.1001-7216.2021.200820 Abstract ( )   HTML ( )   PDF (5891KB) ( )   【Objective】Nitrogen uptake and utilization decide matter accumulation and yield formation of rice. With the shrinking rural labor force and rapid development of machine-transplanting, there were few studies yet on nitrogen uptake under the integration of rice seedling nursing for mechanical transplanting and transplanting machines. In this manuscript, focusing on seedling raising-mechanical transplanting, a key link that connects agricultural machines with agricultural practices, we explored the effects of seedling raising methods and transplanting machines on nitrogen absorption and utilization of mechanically transplanted rice.【Method】Hybrid indica rice F you 498 was used as test material and a three-factor random block experiment was designed(two seedling raising methods: nutrient soil and slime; three seeding amount: 65, 85 and 105 g/plate; two transplanting machines: 4- row walk-on transplanter and 6-row riding high-speed transplanter). 【Result】The seedling raising method, seed quantity and transplanting machine exerted significant or extremely significant effects on nitrogen absorption and translocation in vegetative organs, SPAD value of flag leaf and nitrogen harvest index, nitrogen production efficiency and grain yield of mechanically transplanted rice, and the interaction effect was significant or extremely significant. The nitrogen accumulation and nitrogen use efficiency of mechanically transplanted rice under nutrient soil treatment were higher than those under slime treatment, and the nitrogen translocation amount, translocation rate, contribution rate and nitrogen increase in panicle were higher than those under slurry treatment to a certain extent, with an average increase of 21.12%, 15.20%, 10.03% and 6.45%. With the increasing sowing quantity, the grain yield, nitrogen absorption and translocation amount, nitrogen dry matter production efficiency and nitrogen partial productivity of mechanically transplanted rice increased first and then decreased. Especially, the nitrogen accumulation in mature stage of mechanically transplanted rice with the sowing quantity of 85 g/plate increased by 16.19% and 28.14% on average as compared with the sowing amount of 65 g/plate and 105 g/plate. The yield and its component factors, dry matter weight at seeding stage, nitrogen uptake and translocation amount, nitrogen dry matter production efficiency and nitrogen partial productivity of mechanically transplanted rice with 6-row riding high-speed transplanter were significantly higher than those with 4-row walk-on transplanter.【Conclusion】Given nitrogen accumulation, nitrogen translocation amount, nitrogen accumulation in panicle, nitrogen yield and its components, nutrition soil , coupled with the sowing quantity of 85 g/plate and 6-row riding high-speed transplanter could effectively improve nitrogen uptake and utilization and promote the formation of grain yield.

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Differences in Yield and Rice Quality of Soft <i>japonica </i>Rice with High Quality and High Yield Under Different Nitrogen Levels Qing ZHANG, Baowei GUO, Yajie HU, Hongcheng ZHANG, Yufeng XU, Xiaojie XU, Banghui ZHU, Jiefen XU, Zhongyi NIU, Rongwen TU 2021, 35(6): 606-616.  DOI: 10.16819/j.1001-7216.2021.201101 Abstract ( )   HTML ( )   PDF (443KB) ( )   【Objective】It is very crucial to clarify the response of high quality and high-yield soft rice to nitrogen fertilizer application.【Method】Two soft japonica varieties with high quality and high-yield based on the early selection of varieties were used as experimental materials to study the effects of nitrogen application on the yield and quality under six nitrogen levels including 60 kg/hm2 (N1), 120 kg/hm2(N2), 180 kg/hm2(N3), 240 kg/hm2(N4), 300 kg/hm2(N5) and 360 kg/hm2(N6). 【Result】The yield of soft rice was the highest under 300 kg/hm2 depending on the synergistic increase of panicle number per unit area, grain number per panicle and spikelet number, and there was no significant difference between N5 and N6. With the increase of nitrogen application, appearance, viscosity, balance and taste value of rice increased firstly and then decreased, hardness decreased and then increased with peak at N4 or N5. The brown rice rate, milled rice rate and head rice rate increased with the increase of nitrogen fertilizer, but the chalky rice rate and chalkiness degree both increased first and then decreased, and both were the lowest at N5. With the increase of nitrogen application, the amylose content and gel consistency both decreased but the protein content increased. The peak viscosity, hot paste viscosity, breakdown and final viscosity of rice flour increased firstly and then decreased, with the highest values at N4 or N5. 【Conclusion】In summary, soft japonica rice with high quality and high yield achieved the coordination of yield and quality under N4 and N5, and N4 was the best nitrogen application taking account of quality, yield and benefit.

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Performance of Different Rice Varieties Under High Temperature and Its Relationship with Field Meteorological Factors Haoliang YAN, Song WANG, Xueyan WANG, Chengcheng DANG, Meng ZHOU, Rongrong HAO, Xiaohai TIAN 2021, 35(6): 617-628.  DOI: 10.16819/j.1001-7216.2021.210509 Abstract ( )   HTML ( )   PDF (46149KB) ( )   【Objective】 Heat stress exposure during grain filling stage induced by global warming is projected to have consequences for rice yield and quality. Examining the response of genotypes with contrasting heat tolerance to heat stress during grain filling and the relationship with meteorological factors have important implications for cultivation and breeding. 【Method】 To investigate how grain yield and rice quality is affected by heat stress during grain filling, 48 genotypes with contrasting heat tolerance were sown on four sowing dates for exposure to diversified weather conditions. 【Result】 Significant differences were observed in grain weight and quality of most genotypes across sowing dates. Based on the coefficient of variation and high correlation, 1000-grain weight, head rice rate, and chalkiness were selected to represent the variation of genotypes. Daily average temperature, relative humidity and sunshine hours contributed most to the variance of these traits across sowing dates. The average 1000-grain weight, head rice rate, and chalkiness of susceptible genotypes were 1.98 g, 30.02%, and 19.81% higher than those of tolerant genotypes, respectively. Analysis of the distribution of the membership function value with the average temperature, humidity, and sunshine hours showed the largest differences across genotypes occurs when the average temperature ≥28℃, average humidity ≤84%, and the sunshine hours between 6 h and 10 h. 【Conclusion】 Chalkiness, head rice rate, and 1000-grain weight could be used as representative indicators to estimate the heat stress tolerance of genotypes during the grain filling stage. The meteorological conditions (the average temperature ≥28℃, average humidity ≤84%, and the sunshine hours between 6 h and 10 h) could be used for screening or identification of heat tolerance.

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Auxin Regulator OsGRF4 Simultaneously Regulates Rice Grain Shape and Blast Resistance Yudong CAO, Xiangyi XIAO, Naizhong YE, Xiaowen DING, Xiaoxuan YI, Jinling LIU, Yinghui XIAO 2021, 35(6): 629-638.  DOI: 10.16819/j.1001-7216.2021.210206 Abstract ( )   HTML ( )   PDF (25802KB) ( )   【Objective】Rice grain shape is a complex quantitative trait controlled by multiple genes, which affects rice yield, rice appearance and milling quality simultaneously. It is of great significance to explore the genes related to grain shape and elucidate its genetic basis. Previously, a gene, namely GS2.2, which controls rice grain size, was mapped on the chromosome 2, by using a set of near isogenic lines derived from the small-grain japonica rice variety Nipponbare (NPB) as the recurrent parent, and an indica rice variety Tedaxian(TDX) as the donor parent. 【Method】In this study, fine mapping of GS2.2 and identification of candidate functional genes were carried out. 【Result】 GS2.2 was fine mapped to the 160.6 kb interval between the makers of 2M-7-1 and 2M-9, by using a BC4F2 population with 2887 small grain size plants and a BC4F3 population with 70 large grain size plants. Bioinformatics analysis showed that the 160.6 kb chromosome interval encodes 18 open reading frames (termed as ORF1-18, respectively). Sequence analysis showed that there were five SNP differences in ORF18 between the large grain near isogenic line and Nipponbare. ORF18 encoded an auxin regulatory factor protein OsGRF4. The grain length of ORF18 knockout lines, whose ORF18 was knocked out in large grain near isogenic lines by using CRISPR/CAS9 gene editing technology, became smaller. The above results confirmed that ORF18 was a functional gene of GS2.2. Further identification of ORF18 near isogenic lines (ORF18-NIL) and gene editing knockout lines by in vitro inoculation and disease nursery inoculation showed that the rice blast resistance of ORF18-NIL increased, while that of gene editing knockout lines decreased, indicating that ORF18 also positively regulates rice blast resistance. 【Conclusion】The auxin regulator OsGRF4 found in this study simultaneously regulates rice grain shape and blast resistance, which provides an important gene for breeding rice variety with high yield in coordination with enhanced resistance.