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10 September 2010, Volume 24 Issue 5 Previous Issue    Next Issue
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Research Letter
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Research Letter

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Transgenic Rice Plants Harboring Genomic DNA from Zizania latifolia Confer Bacterial Blight Resistance SHEN Wei-wei,SONG Cheng-li,CHEN Jie,FU Ya-ping,WU Jian-li,JIANG Shao-mei 2010, 24(5): 447-452 .  DOI: 10.3969/j.issn.1001-7216.2010.05.001 Abstract ( )   PDF (855KB) ( )   Based on the sequence of resistance gene analog FZ14 derived from Zizania latifolia(Griseb.), a pair of specific PCR primers FZ14P1/FZ14P2 was designed to isolate candidate disease resistance gene. The pooledPCR approach was adapted using the primer pairs to screen a genomic transformationcompetent artificial chromosome(TAC) library derived from Zizania latifolia. A positive TAC clone (ZR1) was obtained and confirmed by sequence analysis. The results indicated that ZR1 consisted of conserved motifs similar to Ploop (kinase 1a), kinase 2, kinase 3a and GLPL(Gly-Leu-Pro-Leu), indicating that it could be a portion of NBSLRR type of resistance gene. Using Agrobacterium tumafaciensmediated transformation of Nipponbare mature embryo, a total of 48 independent transgenic T0 plants were obtained. Among them, 36 plants were highly resistant to the virulent bacterial strain PXO71. The results indicated that ZR1 contains at least one bacterial blight resistance gene.

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Genetic Structure and Geographical Distribution of Chinese Rice Cultivars Based on Allozymic Alleles JIANG Yun-zhu,TANG Shen-xiang,TANG Jian* 2010, 24(5): 453-462 .  DOI: 10.3969/j.issn.1001-7216.2010.05.002 Abstract ( )   PDF (669KB) ( )   The genetic structure of Chinese rice cultivars was analyzed according to allozyme variation by starch gel electrophoresis. Twelve polymorphic loci coding for 5 allozymes were surveyed among 6330 Chinese rice cultivars including 5492 traditional rice and 838 inbred varieties. Fiftythree alleles were detected with a genetic diversity index of 0.269. The difference in diversity index was not significant between traditional and inbred rice. But total allele number of traditional rice was higher than that of modern inbred varieties. Comparing the allozyme diversity among six rice ecoregions of China, it is found that the diversity center of allozyme is in southwest ecoregion of China, while most rear alleles existing in the rice cultivation regions of North China and East China. This finding indicates that the north and east rice cultivation regions are probably related with the origin of rice in China. The traditional cultivars were clustered into two major groups, indica and japonica. The diversity of indica was higher than that of japonica. The pronounced nonrandom associations among alleles at many unlinked enzyme loci as well as the significant differences of frequencies at individual locus indicate the significant difference between the subspecies of rice, indica and japonica.

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QTL Analysis on Nitrogen Uptake and Related Traits at Seedling Stage in Rice WANG Yan-rong,#,DAI Gui-jin,#,Ryu OHSUGI,Tohuru YAMAGISHI,CHENG Shi-hua 2010, 24(5): 463-468 .  DOI: 10.3969/j.issn.1001-7216.2010.05.003 Abstract ( )   PDF (1799KB) ( )   QTL analysis was done on nitrogen uptake rate and its related traits of rice at the seedling stage with the BIL population derived from Koshihikari/Kasalath//Koshihikari as materials, by the method of hydroponic and isotopic tracer. Shoot dry weight (SW), root dry weight (RW), the ratio of root dry weight to shoot dry weight (R/S), relative growth rate of shoot (RGRS) and relative growth rate of root (RGRR) were closely correlated with nitrogen absorption ability (NAA) and nitrogen absorption rate (NAR). The putative QTLs, including one for SW, four for RW, one for plant nitrogen content, three for NAA, one for HNAE(nitrogen absorption rate at high N level) and one for LNAE(nitrogen absorption rate at low N level), were detected and mainly mapped on chromosomes 6, 7, 8 and 10. There existed significant pleiotropic effects or neighboring expression between the QTLs for NAA, LNAE and RW.

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Mapping QTLs for Drought Resistance at Seedling Stage in Rice by Using a Doubled Haploid Population XU Qun,YUAN Xiao-ping,YU Han-yong,WANG Yi-ping,TANG Sheng-xiang,WEI Xing-hua* 2010, 24(5): 469-473 .  DOI: 10.3969/j.issn.1001-7216.2010.05.004 Abstract ( )   PDF (1681KB) ( )   Abstract: The QTLs for drought resistance at the seedling stage were analyzed by using a doubled haploid (DH) population consisted of 251 lines from the cross between a japonica parent Maybelle and an indica parent Baiyeqiu. A genetic linkage map with 226 SSR markers was constructed. Through singlelocus analysis following composite interval mapping (CIM), a total of 5 QTLs were detected on 5 different chromosomes. Four QTLs were also detected by twolocus analysis, which resolved 4 epistatic QTLs (EQTLs). The additive genetic effects of all QTLs were positive, indicating the alleles from Baiyeqiu improve drought tolerance of the DH population.

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Relationship Between Subspecies Differentiation and Rice Quality Traits in RILs Population from IndicaJaponica Cross MAO Ting,XU hai,GUO Yan-hua,ZHU Chun-jie,CHEN Kai,WANG Jia-yu,JIANG Shu-kun,XU Zheng-jin* 2010, 24(5): 474-478 .  DOI: 10.3969/j.issn.1001-7216.2010.05.005 Abstract ( )   PDF (543KB) ( )   In 2006-2007, the F8 (92 lines) and F9 (142 lines) generations of the recombinant inbred lines (RILs) populations derived from a cross between Qishanzhan (indica cultivar) and Akihikari (japonica cultivar) were used to investigate the Cheng′s index (ChI) and performance of indica/japonica diagnostic SSR markers (Dj value), and 11 rice quality traits. In the study, ChI was used to represent morphological differentiation (ChI<14, indica type; ChI≥14, japonica type) and Dj value was to display genetic differentiation, which is number of SSR loci identical to those of Akihikari divided by total number of SSR loci identical to Akihikari and Qishanzhan (Dj<50, indica type; ChI≥50, japonica type). Both F8 and F9 populations showed a normal distribution in the ChI and Dj values. The number of lines with indica type was similar to those with japonica type based on the ChI values, whereas an obvious japonicainclined distribution was found based on the Dj values in the two populations. There was no significant difference in most rice quality traits except milled rice width between indica and japonica types classified by the ChI values. Based on the Dj values, the two RILs populations could be divided into japonicalinous type (Dj<75) and japonica type (Dj≥75). The japonica type showed significantly higher brown rice rate, milled rice rate and milled rice width, and significantly lower ratio of milled rice length to width than the japonicalinous type. The Cheng′s index had no significant relationship with all the rice quality traits in the two generations. The Dj value had significantly positive correlations with brown rice rate, milled rice rate and milled rice width, and significantly negative correlation with the ratio of milled rice length to width. It is suggested that there was no significant correlation between the morphological differentiation and rice quality traits in japonica rice in northern China, and the milled rice quality could be improved through increasing japonica component in genetic differentiation.

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Screening and Identification of Rice Cultivars with Relatively High Nitrogen Use Efficiency for Tolerance to Phosphorus Deficiency at Seedling Stage SONG Ai-mei,HUANG Xin-peng,SUN Shu-bin,ZHANG Ya-li,XU Guo-hua* 2010, 24(5): 479-486 .  DOI: 10.3969/j.issn.1001-7216.2010.05.006 Abstract ( )   PDF (1963KB) ( )   A hydroponic experiment was carried out to study the responses of 36 rice cultivars with relatively high nitrogen use efficiency to lowphosphorus at the seedling stage and to explore the differences in physiological mechanism between the lowphosphorus tolerant rice cultivars and the lowphosphorus sensitive ones. Great variation existed in the relative values of root dry weight, shoot dry weight, ratio of root to shoot dry weight and tiller number (coefficient of variation: 16.9%,10.9%,114%,16.3%) in different rice cultivars. In addition, correlation analysis showed their relativity was significant or highly significant. Therefore, these four indexes were employed to evaluate the tolerance to phosphorus deficiency comprehensively. Based on these indexes, three rice cultivars were preliminarily screened out as lowphosphorus tolerant and two rice cultivars as lowphosphorus sensitive, respectively. Comparing with the lowphosphorus sensitive cultivars, the lowphosphorus tolerant ones were characterized by more extensive root system coupled with its higher activity, lower Km and Cmin, but higher Vmax and APase activity. However, the lowphosphorus tolerant cultivars differed in physiological mechanism. The research proved the feasibility for screening double efficient rice cultivars of both nitrogen and phosphorus uses. The screened rice cultivars could be used for identifying genes involved in phosphorus efficiency.

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Effects of Mulching Mode on Canopy Physiological, Ecological Characteristics and Yield of Rice under Dry Cultivation ZHANG Yu-zhu,LIU Yang ,ZENG Xiang ,CHEN Kai-lin,HUANG Ze-hui ,XIE Hong-ke 2010, 24(5): 487-492 .  DOI: 10.3969/j.issn.1001-7216.2010.05.007 Abstract ( )   PDF (1256KB) ( )   The effect of mulching mode on leaf physiological and population ecological characteristics of rice was studied by using super hybrid rice combination P88S/1128 as material under three mulching cultivation modes and bare cultivation (control). The results showed that mulching mode had a significant effect on micrometeorological factors and individual growth of rice.There was a significant reduction of rice canopy temperature in hot season, especially in hightemperature periods. Under mulching cultivation, relative humidity increased, creating good microclimatic conditions. At the same time, leaf transpiration increased, leaf temperature decreased under mulching cultivation, which improved the tolerance of rice to high temperature stress, thereby significantly enhanced photosynthetic rate. The yield components under mulching cultivation were obviously improved. With the highest grain number per paincle and seed setting rate, the yield under plastic film mulching cultivation was increased by 1681% compared to the control. Under straw mulching cultivation, the number of effective panicles increased, leading to a yield increase of 959%. However, the rice yield under the liquid film mulching had no significant difference with that of the control.

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Interaction Between Rice Stripe Virus NS3 Protein and Glyceraldehyde-3-Phosphate Dehydrogenase(GAPDH) of Rice XIAO Dong-lai,JIA Dong-sheng,WU Jian-guo,DU Zhen-guo,XIE Li-yan,WU Zu-jian*,XIE Lian-hui* 2010, 24(5): 493-496 .  DOI: 10.3969/j.issn.1001-7216.2010.05.008 Abstract ( )   PDF (516KB) ( )   NS3 protein of rice stripe virus (RSV) is an RNA silencing suppressor. Yeast twohybrid assay was used to screen the rice cDNA library with the NS3 protein as a bait. A novel rice protein interacting with RSV NS3 was obtained. The putative function of the interacting protein was glyceraldehyde3phosphate dehydrogenase (GAPDH). Bimolecular fluorescence complementation (BiFC) also showed that RSV NS3 could interact with the GAPDH. Cellular localization studies showed that GAPDHGFP fusion protein accumulated predominantly in cytoplasm of tobacco (Nicotiana benthamiana) through transient expression assay. Possible functions of GAPDH during the infection of rice by RSV were discussed.

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Study on Recognition Method of Rice Disease Based on Image GUAN Ze-xin,TANG Jian,YANG Bao-jun,ZHOU Ying-feng,FAN De-yao,YAO Qing 2010, 24(5): 497-497～502 .  DOI: 10.3969/j.issn.1001-7216.2010.05.009 Abstract ( )   PDF (839KB) ( )   The recognition method of three kinds of rice diseases (blast, sheath blight, and bacterial leaf blight) was studied by image processing technique and the Bayes discrimination method. Firstly, the disease spots were segmented by color features and their outlines, and 63 parameters of shape, color and texture features were extracted. Secondly, the stepwise discriminant analysis was used to select effective recognition parameters from four parameter sets of shape, color, texture feature and all of them. Finally, the Bayes discrimination method was applied to classify and recognize the three kinds of rice diseases. The results showed that the number of texture parameters decreased to 35.2% and the highest recognition rates of four parameter sets was 97.2%. This method could also be applied to recognize diseases of other crops.

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Action Analysis of Drops of EmamectionBenzoate Microemulsion on Rice Leaf FAN Peng,GU Zhong-yan,XU De-jin,XU Xiao-long,XU Guang-chun 2010, 24(5): 503-508 .  DOI: 10.3969/j.issn.1001-7216.2010.05.010 Abstract ( )   PDF (883KB) ( )   Surface tension and spreading characteristics of drops of 0.5% emamectionbenzoate microemulsion(ME) on rice leaf were studied at concentrations of 0.78-12.50 mg/L. Results showed that the surface tensions of emamectionbenzoate ME at 156, 312, 625 and 1250 mg/L were smaller than the critical surface tension of rice leaf. The contact angles of the drops of these solutions were different when the drops were dropped onto rice leaf. However, as time went on, the contact angle diminished, and the diminishing speed increased with rising concentration. Finally, the drops that the surfactant reached the CMC (critical micelle concentration) in these solutions at 312, 625 and 1250 mg/L spread completely, whereas the drops that the surfactant did not reach the CMC in the solution at 156 mg/L could not spread completely. The surface tensions of emamectionbenzoate ME were smaller than the critical surface tension of rice leaf at 156-100 mg/L while the surface tension of the same concentration of emamectionbenzoate emulsifiable concentrate(EC) were greater than the critical surface tension of rice leaf, and the dynamic retention of the former on rice leaf was significantly greater than the latter. Pot experiment showed that under the same concentration, emamectionbenzoate ME showed an improved protecting effect on Chilo suppressalis compared to emamectionbenzoate EC. It testifies that micro emulsion could improve physical and chemical properties of the agents from the perspective of efficacy.

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Insecticide Resistance Monitoring of Chilo suppressalis in the Drainage Area of the Yangtze River, China HU Jun,CHEN Wen-ming,ZHANG Zhen-zhen,ZHENG Xue-song,JIN Jian-chao,SU Jian-ya,GAO Cong-fen,SHEN Jin-liang 2010, 24(5): 509-515 .  DOI: 10.3969/j.issn.1001-7216.2010.05.011 Abstract ( )   PDF (464KB) ( )   Seventeen populations of Chilo suppressalis Walker were collected from the drainage area of the Yangtze River, including Zhejiang, Jiangsu, Anhui, Hubei, Hunan, Sichuan, and Henan Provinces, China and the resistance of the populations to monosultap, triazophos, chlorpyrifos, fipronil, and abamectin was monitored using topical application in 2008 and 2009. The resistance levels of the 17 populations to the five insecticides varied with the collection regions. The populations from Cangnan, Rui′an, Jiangshan in southern Zhejiang Province (highlevel resistance region) developed extremely high to high level resistance to monosultap (resistance ratio was 43.2 to 177.0fold), triazophos (238.7 to 728.1fold), and chlorpyrifos (31.7 to 57.8fold). At the same time, they had moderate or low level resistance to fipronil (11.2 to 24.7fold) and abamectin (5.9 to 7.1fold) which were widely used in recent years. The populations from Lujiang (Anhui Province), Youxian (Hunan Province) and Gaochun (Jiangsu Province) (moderatelevel resistance region) had extremely high level resistance to triazophos (203.2 to 379.0fold), high to moderate level resistance to monosultap (18.3 to 48.8fold) and chlorpyrifos (29.8fold), and low susceptibility to fipronil (4.4fold) and abamectin (4.1 to 4.7fold). The populations from Yizheng (Jiangsu Province), Hexian (Anhui Province)(low resistance region) showed high level resistance to chlorpyrifos (45.2fold) and triazophos (50.0fold), but moderate level resistance to susceptibility to the other insecticides. The populations from Xinyang (Henan Province), Lianyungang (Jiangsu Province) and Wusheng (Sichuan Province) (susceptibility region) displayed low susceptibility or susceptibility to most of the tested insecticides except monosultap. It is suggested that insecticide resistance management should be based on the local situation of insecticide resistance of C. suppressalis.

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County Level Rice Yield Estimation Based on Combination of Terra and Aqua MODIS EVIs PENG Dai-liang,HUANG Jing-feng,SUN Hua-sheng,WANG Fu-min 2010, 24(5): 516-522 .  DOI: 10.3969/j.issn.1001-7216.2010.05.012 Abstract ( )   PDF (2426KB) ( )   Based on the comparison of enhanced vegetation indices(EVIs) from moderate resolution imaging spectroradiometer(MODIS), linear, quadratic nonlinear and stepwise regression models were constructed with the 16day and 250m resolution vegetative indices of Terra and Aqua(MOD13Q1, MYD13Q1) combined EVIs multiply by township rice planting area and total rice grain yield in Liling City, Hunan Province, China. The optimal fitting models were selected by error analysis, and then the total rice yield in the next year was forecasted. More than 50% absolute values of errors between Terra and Aqua MODIS EVIs were less than 0.03, and 93.22% and 99.50% of them were less than 0.08 and 0.10, respectively. The relative errors of total rice grain yield for all optimal fitting models were less than 0.10%, although forecasting errors were larger than that of fitting, the relative errors of forecasting total rice grain yield were less than 5%.

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evelopment and Identification of Mutants Induced by γray Irradiation from an Upland Rice Variety IRAT109 DENG Shan#,LI Hua-juan#,FENG Fang-jun,XU Xiao-yan,HUANG Zhi-cheng,LUO Li-jun,MEI Han-wei* 2010, 24(5): 523-526 .  DOI: 10.3969/j.issn.1001-7216.2010.05.013 Abstract ( )   PDF (8819KB) ( )   Dry seed samples of the upland rice variety IRAT109 were treated with γray irradiation. Mixed seed bulk was collected from M2 plants. Mutated individuals were collected at seedling, tillering and heading stages from M3 population under dry cultivation and traditional cultivation for several seasons. The mutant population had 260 lines with stablyinherited mutations identified in M5 generation. A proportion of the mutants were described including mutants in leaves, culms, panicles, grains, and drought tolerancerelated traits. The segregation ratios of F2 population were observed for a couple of mutants. In addtion, the problems on screening mutations for drought tolerance and the utility of this mutant population were discussed.

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Investigation of Gene Flow Between Different Rice Varieties under Interplanting QIAN Jun-chao,LUO Qiong*,WANG Yun-yue*,LU Jian-huan,ZHAO Guang-juan,LUO Yan 2010, 24(5): 527-530 .  DOI: 10.3969/j.issn.1001-7216.2010.05.014 Abstract ( )   PDF (632KB) ( )   In order to estimate the frequency of gene flow between varieties under cropland ecological conditions, a field experiment was conducted using Alunuo(a native traditional glutinous variety) and Hexi 41(a modern variety) as materials at Songming and Xundian sites in Yunnan Province, China. The frequency of gene flow was tested by means of SSR analysis. At Songming site, the frequency from Alunuo to Hexi 41 was 0.067%, from Hexi 41 to Alunuo was 0.033%. At Xundian site, both of them are 0.033%. The frequencies of gene flow are very low, indicating that interplanting model would not obviously affect the genetic characters of germplasm.

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Comparison of Rice Quality Characters in Northeast Region of China XU Zheng-jin,HAN Yong,SHAO Guo-jun,ZHANG Xue-jun,QUAN Cheng-zhe,PAN Guo-jun,YAN Ping,CHEN Wen-fu 2010, 24(5): 531-534 .  DOI: 10.3969/j.issn.1001-7216.2010.05.015 Abstract ( )   PDF (1189KB) ( )   The major quality parameters of rice cultivars(lines) for regional yield trials in Liaoning, Jilin and Heilongjiang Provinces, China in 2002-2007 were tested. The results showed that the milling quality was high in all the three provinces. Brown rice percentage and milled rice percentage were the highest in Jilin, and head rice percentage was the highest in Liaoning. There were no significant differences in chalky grain rate and chalkiness between the cultivars from Liaoning and Jilin, but their chalky grain rate and chalkiness were significantly higher than the cultivars from Heilongjiang. The order of the ratio of grain length to width was as follows: Jilin > Liaoning > Heilongjiang, and for protein content, Liaoning > Jilin > Heilongjiang. For amylose content it showed a descending trend as Heilongjiang > Jilin > Liaoning, but the difference between Liaoning and Jilin was not significant. Gel consistency ranked as Liaoning > Heilongjiang > Jilin. A downward trend was found in head rice percentage in the cultivars from Heilongjiang and Jilin and brown rice percentage in the cultivars from Heilongjiang in recent years. Grain length and ratio of grain length to width were significantly and negatively correlated with brown rice percentage and milled rice percentage. Chalky grain rate and chalkiness were significantly and negatively correlated with milled rice percentage, head rice percentage and ratio of grain length to width. In rice breeding and cultivation, more attention should be paid to decreasing chalky grain rate and chalkiness in Liaoning and Jilin, stabilizing head rice percentage in Heilongjiang and Jilin and increasing brown rice percentage in Heilongjiang.

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Resistance Performance of Rice Varieties (Combinations) to Brown Planthopper，Nilaparvata lugens, in Paddy Field SHENG Xian-qiao,ZHANG Fa-cheng,XU Hong-xing,ZHENG Xu-song,CHEN Gui-hua,LU Zhong-xian 2010, 24(5): 535-538 .  DOI: 10.3969/j.issn.1001-7216.2010.05.016 Abstract ( )   PDF (431KB) ( )   Resistance performance of 48 rice varieties (combinations) to brown planthopper (BPH), Nilaparvata lugens Stl, was evaluated in single season rice field during BPH population outbreak of year 2007. Results showed that 16 varieties(combinations) were susceptible while the other 32 varieties (combinations) were highly or moderately resistant to BPH. Bing 04123, Ⅱ you 845, Yixiang 845, Zhongzu 14， Jiaxingyou 041 and IR36 showed high resistance. Besides the 5 varieties with high resistance, other varieties including Xiushui 09, Xinjiayou 99, Jiayou 225, Xiuyou 0969, Ning 0481, Bing 04103, Bing 0408, Bing 04123, R4101, Bing 04132, Bing 05129, Bing 05227, Zhejing 23 and Zhejing 22 also had long durable resistance characteristics. The results imply that rating resistance of rice varieties to BPH in paddy field at the adult stage of rice was much more importance in screening and evaluating resistance resources for optimizing the layout and application of newbred resistant varieties as one of key strategies of integrated pest management.

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Seed Setting Rates and Their Correlations with Meteorological Factors under Normal Climatic Conditions in Super Hybrid Rice in the Jianghan Plain, China TIAN Xiao-hai,WU Chen-yang,YUAN Li,WANG Xiao-ling,MA Guo-hui, 2010, 24(5): 539-543 .  DOI: 10.3969/j.issn.1001-7216.2010.05.017 Abstract ( )   PDF (1555KB) ( )   A multiplesowing experiment was conducted with nine major super hybrid rice combinations (with Shanyou 63 as control) in Hubei, China as materials to elucidate the basic pattern of seed setting rate of super hybrid rice in the midseason rice growing season, and its correlation with cardinal meteorological factors (CMF). Seeds were sown for seven times from April 19 on at a 10day interval, and the seed setting rates of rice plants and the relative CMF were recorded in 2008. The result showed that the overall meteorological condition this year was characterized by more rainy and cloudy than normal, but no typical extreme weather has ever happened. All of the plants of the nine combinations with seven sowing dates showed high and stable seed setting rates. However, the basic pattern of seed setting rate was that the earlier the planting, the greater the seed setting rate, irrespective of the combinations. Seed setting rate decreased with the decrease of daily mean temperature at a rate of 0.8 percent point per 1℃ on average. Various tillers with varied heading dates within the same hill of the same combination showed no difference in seed setting rate in the four earlier sowing crops, from the fifth sowing crop on, the tillers with a later heading within the hill showed a decline in seed setting rate compared to the earlier heading ones. Differences of seed setting rate from different crops were highly correlated with daily mean temperature within 15 days period after heading, the accumulative radiation hours per day within 15 days before and 25 days after heading, and the daily maximum temperature within 7 days before and after heading.

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Research Progress on Mapping of Gene Conferring Resistance to Sheath Blight and Exploitation of Resistance Resources in Rice ZENG Yu-xiang,LI Xi-ming,MA Liang-yong,JI Zhi-juan,YANG Chang-deng* 2010, 24(5): 544-550 .  DOI: 10.3969/j.issn.1001-7216.2010.05.018 Abstract ( )   PDF (489KB) ( )   Sheath blight is one of the major diseases in rice. The breeding and use of varieties resistant to sheath blight is crucial in controlling the disease. The mining of resistance resources, genetic research and mapping of sheath blight resistance genes, and utilization of gene resources in other species are the foundation in breeding sheath blightresistant varieties. This paper reviewed the mapping of loci conferring resistance to rice sheath blight, the evaluation of the potential value of QTLs controlling the resistance, and the latest progress on exploitation of resistance resources against the disease.

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Progress on the Study of the Bentazon Sensitive Mutants in Rice ZHANG Ji-wen 2010, 24(5): 551-558 .  DOI: 10.3969/j.issn.1001-7216.2010.05.019 Abstract ( )   PDF (464KB) ( )   Two rice bentazonlethal mutants, Norin 8m and M8077S, were obtained from japonica and indica rice independently by γray radiation in Japan and China. Both mutants were sensitive to the sulfonylurea herbicides, but insensitive to the other hebicides. Genetic analysis showed that both mutants were controlled by a single recessive gene, and the sensitivities to bentazon and sulfonylurea were controlled by the same gene. Gene mapping, gene cloning and complementation experiment showed that both Norin 8m and M8077S were resulted from a singlebase deletion of CYP81A6, a cytochrome P450 gene. A singlebase deletion of C at the 507th nucleotide coding sequence starting from ATG of CYP81A6 in Norin 8m were identified, compared with a singlebase deletion of G at the 2058th nucleotide in coding sequence starting from ATG of CYP81A6 in M8077S. The bentazonlethal mutants have been used for hybrid seed reproduction to ensure hybrid seed purity for the twoline hybrid seed production. Three photothermosensitive genic male sterility (P/TGMS) lines (M8064S, B88S, and B63S) marked with bentazonlethality and 3 relevant hybrids (Fengliangyou 2, Benliangyou 639, and Benliangyou 9) have been successfully developed and registered in Hubei and Jiangxi Provinces, China. These bentazonlethal mutants have been also used for mixedplanting hybrid seed production. A bentazonsenstive restorer line MC526 and its matched hybrid combination Hunzhi 1 have been developed successfully. The procedures of mixed planting and the key techniques for mechanized production of hybrid seeds have been set up. The paper also reviewed the future applications of CYP81A6 gene in herbicide resistant rice breeding, the safety control of genetically modified rice and the application prospects of chemical emasculation.