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10 March 2009, Volume 23 Issue 2 Previous Issue    Next Issue
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综述与专论
研究报告
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综述与专论

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Genetics and Improvement of Resistance to Bacterial Blight in Hybrid Rice in China ZHANG Qi 2009, 23(2): 111-111～119 .  Abstract ( )   PDF (2483KB) ( )   Since the 1980s, hybrid rice breeding for resistance to bacterial blight in China has been rapidly progressing. The gene Xa4 was mainly used in threeline indica hybrid and twoline hybrid rice grown in a large area. The disease has been seen “quiet” for 20 years in China, yet in recent years it has gradually emerged prevalently in fields planted with newly released rice varieties in the Yangtze River Valley. This situation for scientists inevitably raised several questions: what causes the resurgence? Is the resistance of variety still effective? And/or is resistance breeding still one of the main objectives of rice improvement? What approach do we take on resistance breeding so that the resistance will be more durable, and the resistance gene will be used more efficiently? A combined strategy composed of traditional method, molecular markerassisted selection, and transgenic technology should bring a new era to the bacterial blight resistance hybrid rice breeding program. The review also briefly discusses and deliberates on issues related to the broadening of bacterial blight resistance, and suitable utilization of resistance genes, alternation planting of available resistance genes, and introduces the virulent populations of the bacterial blight pathogen in China even in Asia.

研究报告

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Comparison on Efficiency of Generating Selectable Markerfree Transgenic Rice by Different Transformation Methods YU Hengxiu,LU Meifang,CHEN Xiuhua,GONG Zhiyun,LIU Qiaoquan*,GU Minghong* 2009, 23(2): 120-120～126 .  Abstract ( )   PDF (942KB) ( )   The efficiencies of generating selectable markerfree (SMF) transgenic rice through two transformation methods were compared using four indica and japonica varieties as materials. One is by using a single twin TDNA binary vector in one Agrobacterium strain. The twin TDNA binary vector pYH592 is composed of two separate TDNA regions, one carrying the antisense Wx gene while the other the HPT gene. The other one, known as twovector system, is by using two separate binary vectors in two separate Agrobacterium cultures. The results indicated that the average cotransformation frequencies of the antisense Wx gene and the HPT gene were 10.1% and 45.0% for the four rice varieties, the SMF transgenic plants could be found in the offsprings of 55.6% and 60.0% cotransformants, and the effectivenesses of generating markerfree transformants were 5.6% and 27.0%, respectively, in the twovector system and the twin T-DNA binary vector system.

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Preliminary Study on the Function of Calcineurin BLike Protein Gene OsCBL8 in Rice MA Bojun ,GU Zhimin ,TANG Haijuan ,CHEN Xifeng ,LIU Feng ,ZHANG Hongsheng 2009, 23(2): 127-127～134 .  Abstract ( )   PDF (2396KB) ( )   The homozygous T3 transgenic lines with sense OsCBL8 and antisense OsCBL8 obtained by Agrotransformation were used to investigate the function of OsCBL8 in rice. The results showed that either overexpression or inhibition of OsCBL8 gene in transgenic lines had little effect on main agronomic traits, but significantly decreased the number of filled grains per panicle and seed setting rate in some lines. Semiquantitative RTPCR showed that the expression of OsCBL8 extremely increased in sense transgenic seedlings, and decreased to some extent in antisense transgenic ones. By evaluation of tolerance to 150 mmol/L NaCl, 20% PEG6000 and low temperature treatments, one sense transgenic line with high salt tolerance and one antisense transgenic line with high drought tolerance were obtained, respectively. It is discussed that the OsCBL8 gene may play an important role in rice tolerance to abiotic stresses.

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Construction of Near Isogenic Lines for Pericarp Color and Evaluation on Their Near Isogenicity in Rice WANG Xiaoguang,JI Zhijuan,CAI Jing,MA Liangyong,LI Ximing,YANG Changdeng* 2009, 23(2): 135-135～140 .  Abstract ( )   PDF (1384KB) ( )   The inheritance of purple pericarp was studied through genetic analysis using F2, BC1F1 and F3 from a cross between a purple pericarp rice variety Zixiangnuo and a white pericarp rice variety Chunjiangnuo 2. Seven pairs of near isogenic lines(NILs) for pericarp color of rice were further constructed. The genetic analysis indicated that the purple pericarp was controlled by two complementary genes (Pb and Pp). Analyses on agronomic traits showed that no significant differences on agronomic traits were found among NILs except grain weight. The polymorphic SSR markers for the two parents were detected only in target segments of the five pairs of NILs different in Pb, which revealed that the near isogenicities of them were fine. However, for the two pairs of NILs different in Pp, the polymorphic markers for the two parents were detected as well as in nontarget segments of chromosomes 11 and 12, respectively.

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Analysis on Correlation Between Heterosis and Genetic Distance Based on Simple Sequence Repeat Markers in japonica Rice ZHAO Qingyong ,ZHU Zhen ,ZHANG Yadong ,ZHAO Ling ,CHEN Tao ,ZHANG Qiaofeng ,WANG Cailin 2009, 23(2): 141-141～147 .  Abstract ( )   PDF (887KB) ( )   Genetic diversity among 30 japonica rice was studied using the simple sequence repeat(SSR) markers, and relationship between genetic distance based on SSR markers and yield heterosis was analyzed using the materials consisted of 30 parents and 200 F1 hybrids with a 20×10 diallel crossing design. The results indicated that 64 pairs of SSR primers could produce 185 steady polymorphic bands among 30 parents averaging 2.9 bands for each pair of primers. The polymorphic index content (PIC) values varied from 0.064 to 0.844 with an average of 0.380. Cluster analysis by UPGMA classified 30 parents into seven groups based on genetic similarity, which was coincident with the heterotic groups determined by their pedigree analysis. The correlations between the genetic distance and yield heterosis and hybrid performance were significant except for the total number of spikelets per panicle, and the coefficients of correlations were ranged from -0.361 to 0.359. It is suggested that the molecular markers could be used as a useful tool for assigning heterotic group and measuring genetic diversity, but not for predicting heterosis because the coefficient of relationship between the genetic distance based on SSR markers and yield heterosis was too small.

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SSR Analysis on japonica Rice Landraces from the Taihu Lake Region, China YU Ping,LI Li,LU Jianzhen,YUAN Xiaoping,XU Qun,WANG Yiping,YU Hanyong,WEI Xinghua 2009, 23(2): 148-148～152 .  Abstract ( )   PDF (352KB) ( )   Fortyfive SSR markers were used to study the genetic diversity in 224 japonica rice landraces from the Taihu Lake Region, China. There were 162 alleles at the 45 loci investigated. The number of alleles per locus (Na) ranged from 2 to 7, with a mean value of 3.6. The Nei′s genetic diversity index (He) varied widely from 0.009 (RM169) to 0.663 (RM444) with an average value of 0.197. The genetic diversity of all the traditional ecotypes (green rice, yellow rice, red rice and white rice) was low. Analysis of molecular variance (AMOVA) indicated that most of the genetic variation was from differences among traditional ecotypes. The pairwise comparison of Fstatistics(Fst) revealed a significant genetic differentiation in the four pairs (green rice vs red rice; green rice vs white rice; red rice vs white rice; red rice vs yellow rice), whereas no significant differentiation was found between other types. The results showed that more rare alleles and low genetic diversity were detected in japonica rice landraces from the Taihu Lake Region, China. This will be helpful to conserve and exploit Taihu japonica rice landraces.

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Ideal Type of Rice Core Germplasm Huanghuazhan and Its Derivatives with Good Grain Quality ZHOU Shaochuan,LI Hong,HUANG Daoqiang,LU Decheng,LAI Suichun,ZHOU Degui,WANG Zhidong,FU Chongyun,LI Kanghuo 2009, 23(2): 153-153～159 .  Abstract ( )   PDF (175KB) ( )   To construct the ideal type of core germplasm Huanghuazhan and its derivatives, the performances of Huanghuazhan and its pedigree varieties were investigated in early and latecropping seasons of 2007 in Guangzhou, China （113°17′E, 23°8′N）. In earlycropping season, the yield was significantly and positively correlated to spikelet number per panicle (r=0716) and the length of the 2nd top leaf (r=0.825), and significantly negatively correlated to productive panicle number per plant (r=-0.795). Every 1 unit increase in the spikelet number factor caused an increase of 3.17 unit in yield. In latecropping season, the yield was significantly and positively correlated to 1000grain weight (r=0.734). Eating quality was significantly and positively correlated to length of flag leaf, length of the 2nd top leaf and length of the 3rd top leaf, with correlation coefficients of 0.798, 0.794 and 0.831, respectively. Every 1 unit decrease in the flag leaf width factor had a 2.06 unit increase in yield. Ideal type of the core germplasm Huanghuazhan and its derivatives for early cropping season was different from that for latecropping season. Emphasis should be paid on selection of the plant type with fewer panicles, bigger and longer panicle, and longer functional leaves in earlycropping season and higher 1000grain weight, longer and narrower functional leaves in latecropping season in the breeding nursery in Guangzhou, China.

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Hull Growth and Cytological Differences Between Two Rice Varieties with Long and Short Grains ZHANG Yan ,HU Chun gen ,YAO Jia ling 2009, 23(2): 160-160～164 .  Abstract ( )   PDF (1660KB) ( )   long grain rice variety(Minghui 63) and a short grain rice variety(Chuan 7) were used to observe hull growth and cytological characteristics. The results showed that the internal parenchyma cells carry out symmetrical division in palea at the flower primordium stage. The palea cells continue dividing until the stage of pollen mother cell, ceasing sequentially from the apical to the basal parenchyma cells. Ouring pollen mother cell meiosis, palea cells start rapid elongation and reach the maximum length at the late microspore stage. The middle and basal internal parenchyma cells provide larger contribution to the total length than the apical cells. There was significant difference in total cell number between the two varieties throughout the growth stage, whereas no significant difference in cell length at the late microspore stage. The number of internal parenchyma cells of Minghui 63 was 60.98% more than that of Chuan 7, whereas the middle and basal cell lengths were only 1.81% and 805% longer, respectively. Thus, it is concluded the cell number is the main factor affecting the final palea length.

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Changes in Photosynthetic Indexes of Rice Varieties During Fortyseven Years of Genetic Improvement in Jilin Province， China WU Zhihai ,ZHAO Guochen ,XU Kezhang ,DI Yuting,JIANG Nan,LING Fenglou,ZHAO Yingjun 2009, 23(2): 165-165～171 .  Abstract ( )   PDF (3172KB) ( )   The photosynthetic characteristics of twentyfive rice varieties released from 1958 to 2005 in Jilin Province, China were investigated in 2006 and 2007. The grain yield were linearly increased from 6 671.9 kg/hm2 in 1958 to 11 853.2 kg/hm2 in 2005, with an annual increase of 110.2 kg/hm2 (1.65%) in the 47 years. The harvest index, growth duration and spikelets/leaf area ratio were increased year by year and significantly correlated with grain yield. The photosynthetic rate of leaf increased and significantly and positively correlated with grain yield. The increase in photosynthetic rate was due to the increase in apparent leaf mesophyll conductance. The photosynthetic rate of modern variety was restricted by stomatal factors, due to the decrease of ratio of intercellular CO2 concentration to ambient CO2 concentration with year of release. The increase in transpiration rate exceed to that in photosynthetic rate, thus the water use efficiency descended. It is suggested that the improvement of water use should be paid attention to in future rice breeding.

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A Method to Upscale the Genetic Parameters of CERES-Rice in Regional Applications JIANG Min ,JIN Zhi qing 2009, 23(2): 172-172～178 .  Abstract ( )   PDF (681KB) ( )   In order to upscale the genetic parameters of CERESRice to satisfy the requirements in its regional applications, Jiangsu Province, the second largest rice producing province in China, was taken as an example. The province was divided into four rice regions for different varietal types and five to six sites in each region were selected. Then the eight genetic parameters of CERESRice，particularly the four parameters related to yield were modified and then validated using Trial and Error Method and based on the local statistical rice yield data at a county level from 2001 to 2004, combined with the regional experiments of rice varieties in the province as well as the local meteorological and soil data (Method 1). The simulated results of Method 1 were compared with that of the other three traditional methods upscaling the genetic parameters, i.e., using onesite experimental data of a local representative rice variety (Method 2), using local longterm rice yield data at a county level after deducting the trend yield due to progress of science and technology (Method 3) and using rice yield data at a super scale, such as provincial, ecological zone, country or continent levels (Method 4). The results showed that a good fitness efficiency was obtained by using the Method 1, its correlation coefficients between the simulated yields and the statistical yields were significant at 0.05 or 0.01 statistical levels and the RMSE (root mean squared error) values were less than 9％ for all the four rice regions, which were obviously better than those of the other three traditional methods. The method upscaling the genetic parameters of CERESRice presented is not only valuable for the impact studies of climate change, but also favorable to provide a methodology for reference in crop model applications to the other regional studies.

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Growth Characteristics of Two SuperHighYielding japonica Hybrid Rice Combinations LI Jie ,ZHANG Hongcheng ,QIAN Yinfei,GUO Zhenhua,CHEN Ye ,DAI Qigen,HUO Zhongyang,XU Ke,LI Dejian,HUA Zhengxiong,SHA Anqin,ZHOU Youyan,LIU Guolin 2009, 23(2): 179-179～185 .  Abstract ( )   PDF (906KB) ( )   Growth and dry matter production characteristics, yield formation and yield components of rice under superhighyielding (＞12.0 t /hm2) cultivation were analyzed using two japonica hybrid rice combinations (Lingxiangyou 18 and Changyou 1) in paddy field. The results showed that the number of panicles, the number of grains per panicle, the number of secondary branches per panicle and the number of spikelets on secondary branches under superhighyielding cultivation(SHYC) were significantly higher than those under traditional high yielding (10.5 t/hm2 to 11.0 t/hm2) cultivation(CK). The seedsetting rate and 1000grain weight under SHYC were a little higher than those under CK, but without significant difference. Before the critical leafage for productive tillering, rice under SHYC grew faster and at the critical leafage for productive tillering the number of stems and tillers was up to the expected value, and leaf area index, photosynthetic potential, dry matter accumulation and crop growth rate were larger than those under CK. From the critical leafage for productive tillering to elongation, rice under SHYC had a steady growth with less ineffective tillers and lower peak number of seedlings, and its leaf area index, photosynthetic potential, dry matter accumulation and population growth rate were lower than those under CK. After elongation, with a steady decline in growth and a high productive tiller rate, rice under SHYC had higher leaf area index, photosynthetic potential, dry matter accumulation and population growth rate than under CK. Superhighyielding rice had an obvious growth superiority. Especially after heading, leaf area index, photosynthetic potential, dry matter accumulation and population growth rate were significantly higher under SHYC than under CK.

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Effects of Soil Moisture on Water Utilization Characteristics of Rice (Oryza sativa) LU Xinghua ,WU Lianghuan,PANG Linjiang 2009, 23(2): 186-186～190 .  Abstract ( )   PDF (486KB) ( )   A pot experiment was conducted to study the effect of soil moisture on water utilization characteristics of rice. Results showed that the cumulative water consumption of rice during the whole growth period under conventional flooding cultivation was significantly more than that under nonflooding cultivation with plastic film mulching, but slightly less than that under flooding cultivation with plastic film mulching. Compared to conventional flooding cultivation, the rice grain yield was not decreased or even increased with the increased water productivity under light and no water stress treatments with plastic film mulching. The cumulative water consumption of rice, the water consumption at each growth stage and its consumption intensity were decreased gradually with the decreasing soil moisture. And a significantly quadratic correlation was found between the field waterholding capacity and the cumulative water consumption of rice. The highest water consumption at each stage and the highest periodic consumption ratio were found at the elongation and booting stages under no waterstress treatments with plastic film mulching, and at the milky ripeness stage under the other treatments. With the decreasing soil water content, the periodic consumption ratio gradually reduced before heading and flowering, whereas increased after heading and flowering, in addition, the consumption intensity decreased. The number of effective panicles and the number of grains per panicle decreased with reducing water moisture, resulting in the declined rice yield. However, the water productivity increased gradually first and then decreased with the decreasing soil moisture. Quadratic correlation was also observed between the yield and the water productivity of rice.

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Lodging Resistance in japonica Rice Varieties with Different Panicle Types LI Hongjiao,ZHANG Xijuan,LI Weijuan,XU Zhengjin*,XU Hai 2009, 23(2): 191-191～196 .  Abstract ( )   PDF (608KB) ( )   The difference of lodging resistance for nine japonica rice varieties from northern China with different panicle types was studied. The results showed that lodged culms frequently bend at the second or third internodes, 20 to 40 cm above the ground. The lodging index was significantly and positively correlated with the length of basal internodes and the culm length. Significantly positive correlations were also found between the fresh weight of culm from different internodes to the top, long or short external diameters, area of cross section and breaking resistance, bending moment. The panicle length significantly affected the bending moment of various internodes. Significantly positive correlations were also noted between the fresh weight of panicle, and breaking resistance, bending moment. The neckpanicle angle had no significant effect on the lodging index. For a certain variety, curved panicle doesn′t mean poor lodging resistance. Lodging resistance of varieties varied with the region and variety, therefore, the index should not be evaluated only based on panicle type. In general, rice varieties with erect and semierect panicle from northern China had smaller lodging index and stronger lodging resistance than those with curved panicle. The reasons were as follows: firstly, the varieties with erect and semierect panicle were dwarf with short basal internodes, which increased their lodging resistance; secondly, for the varieties with erect panicle, lodging resistance of basal culm was strong; finally, with short and light panicles, the varieties with erect and semierect panicles had slight bending degree of panicle neck, which reduced the force to stalk. In addition, the relationship between ecological environment, characteristics of varieties, panicle type and lodging resistance were also discussed.

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Resistant Starch Granules RS2 in Rice Varieties Basmati 370 and Koshihikari JIAO Guiai ,TANG Shaoqing,LUO Ju,WU Dianxing,HU Peisong 2009, 23(2): 197-197～200 .  Abstract ( )   PDF (843KB) ( )   The components and chain length distribution of resistant starch granules RS2 in a high quality indica rice Basmati 370 and a high quality japanica rice Koshihikari were studied. The RS2 components of the two varieties were mostly amylose, and the results analyzed by the Size Exclusion Chromatography (SEC) indicated that the amylose included not only the amylose linear chains but also the branched amylose chains and the long chains of amylopectin. Analysis on chain length distribution of RS2 branched chains showed that for both the two varieties, the proportion of long chains(Degree of polymerization＞36) were more than 26%.

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Adult Stage Resistances to Brown Planthopper, Nilaparvata lugens of Rice Varieties with Different Seedling Resistances CHEN Feng,FU Qiang,LUO Ju,LAI Fengxiang,GUI Lianyou 2009, 23(2): 201-201～206 .  Abstract ( )   PDF (1024KB) ( )   Adult stage resistances to the brown planthopper (BPH), Nilaparvata lugens (Stl) of six rice varieties with different seedling resistances were evaluated in Fuyang, Zhejiang Province, China. The six varieties were Shanyou 63（with Bph1 gene）, IR42（with bph2 gene）, IR56 (with Bph3 gene), TN1 (susceptible control) and two newlybred hybrid rice combinations Zhongzheyou 1 and Guodao 6. The rice varieties with moderate resistance or high resistance to BPH at the seedling stage showed resistance at the adult stage. And the varieties highly susceptible at the seedling stage were susceptible at the adult stage. However, the time and degree for hopperburn in field were some different among those susceptible varieties. Hopperburn occurred five days later on Zhongzheyou 1 than on TN1, even if the resistance degrees of those two rice varieties were both at 9 in seedling screening. This suggests that Zhongzheyou 1 had obvious tolerance to BPH which cannot be detected in seedling screening. Therefore, the emphasis should be paid on screening of the adult stage resistance further for new rice varieties which were susceptible at the seedling stage and had good grain quality and (or) high yielding.

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Weed Community Characteristics and Comprehensive Evaluation on Weeds in Paddy Fields under LabourSaving Cultivations in Middle Jiangsu Province, China LI Shushun,ZHANG Lianju,QIANG Sheng* 2009, 23(2): 207-207～214 .  Abstract ( )   PDF (712KB) ( )   Investigations on weed community characteristics and weed infestation in paddy fields under longterm laboursaving cultivation was conducted in 138 randomly sampled fields of 14 sites in Yangzhou, Taizhou and Nantong Prefectures in the middle of Jiangsu Province, China by the sevenscale visualization. The data were analyzed by principal component analysis combined with comprehensive evaluation. Thirtysix weed species, belonging to 33 genus of 18 families, were found. The families including the most weed species were Gramineae, Cyperaceae, Compositae, Scrophulariaceae, Alismataceae and Lythraceae. Four weed species Echinochloa crusgalli,Ammannia baccifera,Eclipta prostrata and Leptochloa chinensis showed high dominance and frequency in the three surveyed prefectures, with frequencies of or near 100%. However, there were regional differences in weed infestation level. Yangzhou was the worsthit area, followed by Taizhou and Nantong. Different cultivation techniques corresponded to different dominant weeds, such as Monochoria vaginalis and A. baccifera in the mechanizedtransplanting mode; A. baccifera, Digitaria sanguinalis, M. vaginalis and L. chinensis in the wheatrice interplanting mode; E. crusgalli, M. vaginalis and Ammannia baccifera in the parachute transplanting mode; E.crusgalli, A. baccifera and M. vaginalis in the flooded direct seeding mode; E. crusgalli, A. baccifera and L. chinensis in the dry direct seeding mode. Compared with the conventional manual transplanting mode, the weed communities in paddy fields under the laboursaving cultivations not only had higher species richness, but also had higher dominance. The order of the weed infestation level, from low to high, were conventional manual transplanting＜mechanizedtransplanting＜parachute transplanting＜flooded direct seeding＜dry direct seeding＜wheatrice interplanting.

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Phytic Acid Content in Different Parts of Grain and Its Correlation with Rice Quality Traits WANG Hui,LI Maobai,ZHANG Jianming,SHI Yingyao,LEE Jung Ro,PIAO Zhongze 2009, 23(2): 215-215～218 .  Abstract ( )   PDF (1146KB) ( )   Phytic acid content in different parts of grain and rice quality traits were analyzed using thirteen different types of rice. The average phytic acid contents in rice bran, brown rice, glume, and milled rice were 48.51, 9.77, 140 and 0.91 mg/g, respectively. Phytic acid content in different parts of grain for different types of rice had a significant difference. The order of the phytic acid accumulation was as follows: rice bran>milled rice>glume. The phytic acid content in rice bran had a significantly positive correlation with those in brown rice and glume. The phytic acid contents in brown rice and rice bran both had a significantly negative correlation with the protein content in rice, and a significantly positive correlation with the 1000grain weight.

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Effect of Nitrogen Application on Ecological Fitness of the Whitebacked Planthopper, Sogatella furcifera on Rice （Oryza sativa） XU Hongxing,ZHANG Juefeng,ZHENG Xusong,YU Xiaoping,LU Zhongxian* 2009, 23(2): 219-219～222 .  Abstract ( )   PDF (2463KB) ( )   The ecological fitness including nymphal development duration, survival rate, female adult weight and fecundity of the whitebacked planthopper (WBPH) on rice varieties Shanyou 63(hybrid), Xiushui 63(japonica) and Zhe 733(indica) at different nitrogen fertilizer levels were investigated. The WBPH population on the same rice variety with high nitrogen application (NH) developed more quickly than that without nitrogen application (NL). The nymphal duration shortened on the NH rice plants and prolonged on the NL rice plants with increasing WBPH generation. The survival rate of nymph was significantly increased with nitrogen application. Higher body weight and fecundity of the female adult and hatchability of eggs were observed in WBPH feeding on NH rice plants than those on NL rice plants. And the same trends were noted in the increasing WBPH generation. There were significant effects of rice varieties, nitrogen levels and WBPH generation on the weight and fecundity of the female adult.