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10 November 2007, Volume 21 Issue 6 Previous Issue    Next Issue
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Progress on Transferring Elite Genes from Non-AA Genome Wild Rice into Oryza sativa Through Interspecific Hybridization FU Xue-lin ,LU Yong-gen ,LIU Xiang-dong ,LI Jin-quan 2007, 21(6): 559-566 .  Abstract ( )   PDF (75KB) ( )   The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hubridization are in three respects,that is,breeding monosomic alien addition lines(MAALs),constructing introgression lines(ILs)and analyzing the heredity of the characters and mapping the relative genes.There are serious reproductive barriers between the interspecific hybridization of O.sativa with non-AA genome wild rice,which mainly show as incrossability and hybrid sterility.This is the "bottleneck" for transferring elite genes from wild rice to O.sativa.Combining traditional crossing method with biotechniques is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.

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Nutrition-Functional Rice Created by Polymerizing ADP-Glucose Pyrophosphorylase (AGP) and Giant Embryo (ge) Genes ZHANG Guang-heng ,ZENG Da-li ,GUO Long-biao ,LIU Hui-juan ,HU Jiang ,GAO Zhen-yu ,HUA Zhi-hua ,QIAN Qian 2007, 21(6): 567-572 .  Abstract ( )   PDF (244KB) ( )   T5 pure lines of japonica rice variety Zhongchao 123 with glgC-TM gene mediated by Agrobacterium transformation,which were used as donor parent of AGP(ADP-glucose pyrophosphorylase)gene,were crossed with a nutrition-functional japonica rice variety Jupei 1 with ge gene.Sixteen lines with genes glgC-TM/ge were screened from 64 lines in F4 generation by molecular marker and morphological observation on the seed embryo from single rice plant.The physical-chemical characteristics and γ-aminobutyric acid(GABA)content of rice grains were measured for the five F4 lines with good performance of multiple traits.The results showed that all the embryo weight per 100-seed from the five F4 lines were significantly higher than that of the parent Zhongchao 123 with an increase of 70.2% at least and 119.0% at most,and the GABA content of the five F4 lines increased by 102.93% to 194.14% compared with the parent Zhongchao 123.However,the eating quality characteristics such as gel consistency,alkali spreading value and amylose content had no obvious changes in the selected lines.The amylose contents of the indicaclinous F4 lines were significantly beyond the two parents while those of the japonicaclinous ones were close to the parents,which indicated that the genes glgC-TM and ge were both expressed in the process of starch synthesis and embryo development of grains,thus leading to the increase of 1000-grain weight and embryo size.Based on these results,the breeding by molecular design combining with bio-technology and traditional technology was considered as an effective way to improve the nutrition-functional fortification and rice grain yield.

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Analysis on Genetic Diversity of Natural Populations of Oryza rufipogon Distributed in Hainan Province by SSR Markers WANG Yi-ping ,WEI Xing-hua ,YUAN Xiao-ping ,YU Han-yong ,XU Qun ,TANG Sheng-xiang 2007, 21(6): 573-578 .  Abstract ( )   PDF (366KB) ( )   A set of 48 SSR markers was used to assess the genetic diversity in 11 natural populations of common wild rice(Oryza rufipogon Griff.)from Hainan Province,China.The results showed that the genetic variability of the common wild rice in Hainan is relatively high(Na=8.3,He=0.716).Seventy alleles(17.6%)were found in only one of the 11 populations and a large number of alleles(77.6%)were at low frequency.For most SSR loci and populations,expected heterozygosities(Nei’s He)under Hardy-Weinberg equilibrium were apparently lower than the observed heterozygosities,indicating a considerable excess of heterozygotes within populations.Genetic variation among populations varied widely,ranging from the lowest diversity values in Yacheng population(Na=1.7,He=0.348)to maximal diversity in Heqing(Na=4.0,He=0.577)and Yelin-B(Na=4.0,He=0.531)populations.A Mantel test revealed that the pairwise Nei’s genetic distance between populations was significantly correlated with geographical distance(r=0.386,P=0.004).Genetic differentiation was weak but significant between populations of East and West Coast regions(Fst=0.048,P=0.024).Of the total differentiation among populations,33.3% was explained by divergence among populations within a region,meaning most of the genetic diversity was due to differences within populations.A mean Nm value of 0.404 suggested a limited gene flow among the assayed populations.Based on the results in genetic diversity and allele frequency analysis,it was suggested that populations both in Heqing and Yelin-B should be given conservation priority.

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Molecular Mapping of Rice Blast Resistance Gene in a japonica Landrace Heikezijing from the Taihu Lake Area,China LI Pei-fu ,SHI Xiao-liang ,WANG Jian-fei ,LIU Chao ,ZHANG Hong-sheng 2007, 21(6): 579-584 .  Abstract ( )   PDF (314KB) ( )   A japonica landrace Heikezijing from the Taihu Lake area,with high resistance to rice blast(Magnaporthe grisea),was crossed with a susceptible variety Suyunuo to get F1,F2 and F2∶3 populations.The recombined inbred lines F5∶6 were obtained from F2 generation by means of single seed descendant method.The parents,F1,F2,F2∶3 and F5∶6 populations were inoculated with Japanese blast strain Hoku 1 to illustrate the inheritance of resistance to the rice blast in Heikezijing.The resistance to Hoku 1 in Heikezijing was controlled by one dominant gene,tentatively designated as Pi-hk1(t).The gene Pi-hk1(t)was further mapped based on the reaction to the rice blast in various generations,combined with SSR molecular markers.It was located on the end of long arm of chromosome 11 and linked to the markers RM7654 and RM27381,with a distance of 0.9 cM and 1.6 cM,respectively.

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Mapping of QTLs for Na+ Content in Rice Seedlings under Salt Stress WANG Bin ,LAN Tao ,WU Wei-ren 2007, 21(6): 585-590 .  Abstract ( )   PDF (1673KB) ( )   Based on a recombinant inbred population consisting of 131 lines derived from a cross between two indica rice varieties,H359 and Acc 8558,and a corresponding genetic map comprising 147 RFLP and 79 SSR markers,QTL mapping was performed for salt tolerance in rice indicated by Na+ content in shoots of seedlings after treatment with 150 mmol/L NaCl by using the method of composite interval mapping.A total of 13 QTLs were detected on chromosomes 1,2,5,6,7 and 12,which could explain 60.88% of total phenotypic variance.Among the QTLs,qSC1b had the largest additive effect,explaining about 45% of the phenotypic variance.The QTLs identified in this study shared the same or similar regions with many salt-stress-related QTLs/genes reported previously.

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Analysis of Inheritance and QTLs of Rice Starch Viscosity (RVA Profile) Characteristics ZHANG Qiao-feng ,ZHANG Ya-dong ,ZHU Zhen ,ZHAO Ling ,ZHAO Qing-yong ,XU Ling ,WANG Cai-lin 2007, 21(6): 591-598 .  Abstract ( )   PDF (2403KB) ( )   The rice starch viscosity (RVA profile) characteristics has been proved useful for the evaluation of eating and cooking quality in rice breeding program. To study the inheritance of the RVA profile, an F2 population of Wuyujing 3/Aichi 106 was used. The results indicated that peak viscosity (PKV) was a typical quantitative character; hot paste viscosity (HPV), cool paste viscosity (CPV), setback viscosity (SBV), breakdown viscosity (BDV), consistence viscosity (CSV) might be controlled by a major gene and several minor genes; and peak time (PeT) might be controlled by two major genes and several minor genes. In order to understand the genetic basis of the paste viscosity characteristics, the recombinant inbred line populations derived from Nikken 2/Milyang 23 and its genetic linkage map were used to map the QTLs controlling RVA profiles in 2005 and 2006. The results showed a total of 34 QTLs distributed on chromosomes 1, 2, 3, 4, 6, 7 and 8 in 2005 and 2006, including 19 and 15 QTLs in 2005 and 2006, respectively; eight QTLs were both found in two years, the qHPV6, qCPV6, qCSV6, qSBV6, qBDV6 were located on chromosome 6, while qHPV2, qCSV2, qCPV2 were located on chromosome 2. The genes involved in amylopectin synthesis on chromosome 2 were greatly related with RVA profile.

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Improving Blast Resistance of a Thermo-Sensitive Genic Male Sterile Line GD8S by Molecular Marker Assisted Selection JIN Su-juan ,LIU Wu-ge ,ZHU Xiao-yuan ,WANG Feng ,LI Jin-hua ,LIU Zhen-rong ,LIAO Yi-long ,ZHU Man-shan ,HUANG Hui-jun ,LIU Yi-bai 2007, 21(6): 599-604 .  Abstract ( )   PDF (1086KB) ( )   The broadspectrum blast resistance gene Pi1, from the donor line BL122, was introduced into a thermosensitive genic male sterile (TGMS) line GD8S, which possessed good grain quality but high susceptibility to rice blast, by using backcross breeding and molecular markerassisted selection. Five elite improved male sterile lines RGD8S1, RGD8S2, RGD8S3, RGD8S4 and RGD8S5, were selected based on the results of molecular marker analysis, spikelet sterility, recovery ratio of genetic background and agronomic traits. Thirtythree representative blast isolates collected from Guangdong Province, China were used to inoculate the improved lines and the origin line GD8S artificially. The resistant frequency of the improved lines ranged from 75.76% to 100.00%, much higher than that of the check GD8S, which was only 9.09%. On the agronomic characters, there was no significant differences between the improved lines and the check GD8S except for flag leaf length and panicle number per plant. The improved lines could be used for breeding hybrid rice with high blast resistance.

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Marker Assisted Selection for Yield Enhancing QTLs in the Progeny of 9311× Oryza rufipogon and Its Effects in Rice Breeding DENG Hua-bing ,DENG Qi-yun ,CHEN Li-yun ,YANG Yi-shan ,XIONG Yue-dong ,KONG Fan-na ,WANG Bin ,YUAN Long-ping 2007, 21(6): 605-611 .  Abstract ( )   PDF (383KB) ( )   A weedy relative of cultivated rice, Oryza rufipogon from Malaysia, contains two favorable yieldenhancing QTLs (yld1.1 and yld2.1) on chromosomes 1 and 2, which are capable of improving the yield of rice by 18% and 17%，respectively. To transfer the two QTLs into cultivated rice, a restorer line of twoline hybrid rice, 9311, was used as a recurrent parent, and Oryza rufipogon as a donor parent of yieldenhancing QTLs. Four molecular markers, RM166, RM208, RM9 and RM5, which linked to the two yieldenhancing QTLs (yld1.1 and yld2.1), were used to identify the individuals possessing the Oryza rufipogon markers and good agronomic characters in the advanced backcrossed population from “9311” and Oryza rufipogon based on the genotype and phenotype, and some improved 9311 lines containing the two yieldenhancing QTLs were developed. The yield potential of the improved 9311 lines with more numbers of effective panicles and total grains was higher than that of 9311. Some promising hybrid had been developed with super highyielding potential. The results indicated that the two yieldenhancing QTLs were expressed well in genetic background of 9311 and its hybrids.

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Analysis on Combining Ability of Two-Line indica Hybrid Rice WU Zhen-yong ,LI Chun-hai ,MOU Tong-min 2007, 21(6): 612-618 .  Abstract ( )   PDF (48KB) ( )   Five newly developed photo-and thermo-sensitive genic male sterile lines,Hua 884S,Hua 885S,Hua 886S,Hua 893S and Hua 328S and the control Pei’ai 64S which has been widely utilized in rice production were used as female parents,and six newly developed restorer lines,Huahui 2185,Huahui 1035,Hua 1108,BR06,Hua 190 and Huahui 3 were used as male parents.Thirty-six crosses were made according to NCⅡ mating design.The plots of F1s were arranged in the field in a randomized complete block design with three replications in Hainan Province in spring and Hubei Province in summer in 2006,respectively.Grain yield per plant and other nine traits were investigated,and combining ability was analyzed.Both general combining ability(GCA)and specific combining ability(SCA)were significant at 5% or 1% levels for most traits,and the additive effects were more important than non-additive effects.GCA of yield in five newly developed sterile lines was similar,but significantly higher than that in Pei’ai 64S.Hua 885S was the best female parent with the highest GCA and SCA in yield,and Hua 893S was the best sterile line with the highest GCA and SCA in increasing number of grains and number of filled grains per panicle.Hua 328S with the highest negative GCA effect and bigger SCA of growth duration could be used for developing medium and late indica hybrid rice.Hua 884S with the highest negative GCA and bigger SCA of plant height could be used for developing lodging-resistant and dwarf hybrid rice.Huahui 2185,which had the highest GCA and SCA of yield,higher GCA of 1000-grain weight,panicle length,seed setting rate and growth duration,was an ideal male parent.Hua 1108 was better for GCA and SCA of plant height,number of grains per panicle and grain density on panicle.Moreover,the top ten combinations with the biggest SCA effect were also the top ten combinations with the highest yield,implying that the combinations with strong heterosis would be made between one parent with higher GCA and another parent with bigger SCA or both parents with bigger SCA.

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Discrimination of indica and japonica Subspecies and Variations of Vascular Bundle Characteristics in Recombinant Inbred Lines Derived from an indica/japonica Cross ZHU Chun-jie ,XU Hai ,GUO Yan-hua ,WANG Jia-yu ,LIU Hong-guang ,XU Zheng-jin 2007, 21(6): 619-624 .  Abstract ( )   PDF (1498KB) ( )   A recombinant inbred line(RIL)population derived from a cross between Qishanzhan(typical indica)and Akihikari(typical japonica)was used as materials.The result of subspecies discrimination in F6 and F8 generations based on the Cheng’s index and vascular bundle characteristics showed that intermediate type lines were dominant and both populations were japonicalinous.The vascular bundle characteristics which were significantly different between indica and japonica were recombined in the RIL population.The discrimination results based on the ratio of large to small vascular bundles in panicle neck(RLSVB)and the ratio of large vascular bundles between the second internode from the top and panicle neck(RLVB)were consisted with those by the Cheng’s index,so they could be regarded as the parameters for subspecies classification.Moreover,these parameters were more stable than the number of large or small vascular bundles in panicle neck or the second internode from the top among different generations.Because most lines in the populations were intermediate type without complete indica and japonica differentiation,the discrimination results in a certain line based on RLSVB and RLVB might be different.

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Effect of Site-Specific Nitrogen Management on Rice Quality LIU Li-jun ,WU Chang-fu ,ZHANG Hao ,YANG Jian-chang ,ZHAO Bu-hong 2007, 21(6): 625-630 .  Abstract ( )   PDF (475KB) ( )   Under the field experiment conditions,effects of site-specific nitrogen management(SSNM)on grain yield and grain quality of rice were studied.SSNM significantly reduced nitrogen applied rate without any sacrifice in grain yield.When compared with farmers’ fertilizer practice,SSNM increased milling quality and transparency,whereas decreased chalky grain rate,chalky area and chalkiness,leading to an improvement in appearance quality.SSNM also decreased amylose content,gelatinization temperature and protein content,but increased gel consistency.In addition,SSNM increased peak viscosity and breakdown values and decreased setback values,resulting in an improvement in cooking quality.Similar results were obtained from the farmers’ field demonstration.The reason that SSNM improves grain quality was discussed.

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Effects of Application of Ecological Fertilizer Combined with Chemical Fertilizer on Rice Yield and Nitrogen Use Efficiency ZHU Lian-feng,YU Sheng-miao,OUYANG You-nan,KANG Wen-qi,DONG Cheng-qiong,XU De-hai,JIN Qian-yu* 2007, 21(6): 631-636 .  Abstract ( )   PDF (1488KB) ( )   To test the effects of application of ecological fertilizer NutriSmartTM combined with chemical fertilizer(NSCF)on rice yield and nitrogen use efficiency,a field experiment was carried out in Hangzhou,China.Under NSCF treatments a gently increase in the number of tillers and a higher percentage of effective tillers were noted while under the control(chemical fertilizers only)treatment,the number of tillers increased rapidly with more unproductive tillers.The grain yields in NSCF treatments increased significantly by 6.40% to 9.53%(in Shanyou 63)and 6.70% to 9.52%(in Xiushui 63)compared to the control,with no significant differences in grain yields among NSCF treatments.Agronomic nitrogen use efficiency(ANUE,being difference in grain yields between nitrogen and non-nitrogen treated plots divided by N applied)and fertilizer nitrogen recovery efficiency(NUE,being difference in N uptakes between nitrogen and non-nitrogen treated plots divided by N applied)in each NSCF treatment of Shanyou 63 and Xiushui 63 were significantly higher than those of the control.It could be concluded that rational application NSCF contributed to an early vigorous growth of rice,a sufficient supply of nutrients during the middle-late growth period,an increase in green leaf area during the grain filling period,accelerating the translocation of the photosynthates to panicles and grains,and finally enhancing the total dry matter production and the grain yield.Meanwhile,rational application NSCF could reduce the application of N fertilizer on rice and improve the nitrogen use efficiency.

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Effects of Nitrogen Application Time on Caryopsis Development and Grain Quality of Rice Variety Yangdao 6 XIONG Fei ,WANG Zhong ,GU Yun-jie ,CHEN Gang ,ZHOU Peng 2007, 21(6): 637-642 .  Abstract ( )   PDF (2364KB) ( )   Pot experiments were conducted to study the effects of different nitrogen application time(at the tillering and booting stages under the same nitrogen amounts)on caryopsis development and grain quality of rice variety Yangdao 6.The increased nitrogen fertilizer(urea),especially at the booting stage,could evidently increase head rice rate,milled rice rate and protein content in grains compared with the control,while decrease chalky grain rate and amylose content.The increased nitrogen fertilizer applied at the tillering and booting stages could significantly affect caryopsis development and enhance grain weight,with more obvious when applied at the booting stage.In the course of caryopsis development the increased topdressing of nitrogen fertilizer at the tillering and booting stages could obviously decrease the total starch and amylose contents,but not obviously for amylopectin content.Increased topdressing of nitrogen fertilizer,especially at the booting stage,had significant effect on the development and structures of amyloplasts and protein bodies.That is,it could change the distribution,numbers and shapes of amyloplasts and protein bodies in the endosperm cells especially in grain abdomen.Compared with the control the arrangements of amyloplasts and protein bodies were closer,with more numbers and higher density and less interspaces each other.Furthermore,most amyloplasts showed polyhedron under the increased nitrogen fertilizer.

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Effects of Drought Stress at Different Growth Stages on Grain Yield and Milling Quality of Rice WANG Cheng-ai ,WANG Bo-lun ,ZHANG Wen-xiang ,ZHAO Lei ,ZHAO Xiu-zhe ,GAO Lian-wen ,HOU Wen-ping 2007, 21(6): 643-649 .  Abstract ( )   PDF (49KB) ( )   The effects of soil drought stress(soil water potential,SWP)on grain yield and milling quality of rice were investigated using Nongda 3,a japonica variety,as material through a pot experiment under artificially-controlled soil water potential with a tension-meter.The result indicated that the yield decreased when SWP was reduced to-75 kPa at different growth stages.The sensitivity degree ranked as follows:mid-booting stage(11-20 d before heading)> late booting stage(1-10 d before heading)> mid-tillering stage(11-20 d after transplanting)>early booting stage(21-30 d before heading)> early tillering stage(1-10 d after transplanting)> late tillering stage(21-30 d after transplanting)> milky stage(31-40 d after heading)>heading stage(1-10 d after heading)> filling stage(21-30 d after heading)> wax ripening stage(41-50 d after heading).The sensitive periods to drought before heading were at mid-booting,late booting and mid-tillering stages,and after heading,it was more sensitive from heading to milky stage than at wax ripening stage,but less sensitive than before heading.Mid-booting stage was the most crucial stage affecting brown and milled rice rates,followed by late booting stage.Meanwhile,11-40 d after heading and 1-20 d before heading were the sensitive stages when drought stress might greatly influence head rice rate,although drought stress at other stages also affected head rice rate.

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Mating Type and Fertility of Magnaporthe grisea Populations from Rice in Ningxia Hui Autonomous Region,China LI Wen-qiang ,WANG Yuan-chao ,ZHENG Xiao-bo 2007, 21(6): 650-656 .  Abstract ( )   PDF (165KB) ( )   To determine mating type and fertility of Magnaporthe grisea populations from rice in Ningxia Hui Autonomous Region,northwestern China,four hundred and sixty isolates from different rice varieties were tested with high fertile standard testers including TH12(MAT1-1),KA3(MAT1-1),TH16(MAT1-2),and Guy11(MAT1-2)in 2002-2005.Of the 460 monoconidial isolates,363(78.9%)were fertile and produced perithecia when paired with either of the four testers,and 97(21.1%)were infertile and did not produce perithecia when mated with any of the four testers.All fertile isolates were male fertile and belonged to a single mating type,MAT1-1,no female fertile and hermaphroditic isolates were detected in sample populations.Among the 363 fertile isolates,79(21.8%)produced perithecia,asci,and ascospores,others produced only barren perithecia.Mating type distribution and fertility status were irrespective of the host variety or geographical location or year of collection of isolates.In a PCR-based mating type assay,the total 460 M.grisea field isolates were identified as MAT1-1,which entirely corroborated the result of standard mating assays using fertile testers.The presence of only one mating type and the absence of female fertile isolates indicated that sexual reproduction was rare or absent in M.grisea populations associated with rice in Ningxia Hui Autonomous Region,northwestern China.

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Disease and Insect Pest Resistance and Agronomic Traits of Rice Variety ZH5 with Sheath Blight Resistance HUANG Shi-wen ,WANG Ling ,WANG Quan-yong ,TANG Shao-qing ,E Zhi-guo ,WANG Lei 2007, 21(6): 657-663 .  Abstract ( )   PDF (351KB) ( )   An experiment on identification of disease and insect pest resistance was conducted through artificial and natural disease inoculations in greenhouse and fields in 2005 and 2006.The results indicated that ZH5 was resistant to rice sheath blight(Rhizoctonia solani),rice blast(Magnaporthe grisea),rice bacterial leaf blight(Xanthomonas campestris pv.oryzae)as well as the brown planthopper(Nilaparvata lugens).ZH5 showed good agronomic characters and ideal plant types.With high quality,high yield and multiple resistance,ZH5 is an ideal material for green and high quality rice production,and also for multiple-resistance rice breeding,especially for sheath blight-resistant rice breeding.

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Classification of Empty and Healthy Panicles in Rice Plants by Hyperspectral Reflectance Based on Learning Vector Quantization (LVQ) Neural Network LIU Zhan-yu ,SUN Hua-sheng ,HUANG Jing-feng 2007, 21(6): 664-668 .  Abstract ( )   PDF (938KB) ( )   The incidence of disease and insect stresses in rice brings about numerous empty panicles.Differentiation of empty rice panicles from healthy ones was the basis of plant protection strategies and damage assessment.The hyperspectral reflectance of healthy rice panicles and empty ones caused by Chilo suppressalis(Walker)and rice panicle blast were obtained in the laboratory.Red edge and green peak parameters derived from first-order derivative spectrum were treated as the input vectors of learning vector quantization(LVQ)neural network.Rice panicles were classified into two classes with 30 epochs by LVQ neural network using the training sample(n=108).The performance of LVQ neural network was examined with the testing sample(n=74),and empty and healthy rice panicles could be successfully differentiated without errors.The result demonstrated that the new method was feasible to differentiate empty rice panicles from healthy ones and supplement or substitute the conventional visual survey.

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Detection of Rice Shape Based on Machine Vision CHEN Jian-hua ,YAO Qing ,XIE Shao-jun ,SUN Cheng-xiao ,ZHU Zhi-wei 2007, 21(6): 669-672 .  Abstract ( )   PDF (818KB) ( )   Artificial detection of rice kernels takes a lot of time and energy and its accuracy is hard to be controlled.To seek a convenient method for detection of rice shape,a real-time vision-based detection approach was developed,which used an improved Ostu algorithm to segmentate the image,eliminated the noise of image by open operation,and calculated rice shape characteristic values by the minimum enclosing rectangle method.Comparing with the methods by ruler and microparticle,the new detection method was of higher accuracy,stronger robustness and better efficiency and could be applied to practical measurement.

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Total Content and Polymorphism of Seed Storage Proteins in Rice JIANG Dong-hua ,YANG Bao-feng ,YE Yan ,LI Jie ,HUANG Da-nian ,WEI Xing-hua 2007, 21(6): 673-676 .  Abstract ( )   PDF (710KB) ( )   Rice seed storage protein contents in 110 rice varieties or lines were determined by using the staining method with Comassie brilliant blue G-250.There were obvious diversities of seed storage protein contents among the varieties or lines tested.The contents of rice seed storage proteins ranged from 34.29 to 95.08 mg/g,but 66.3% varieties or lines were in the range of 40 to 60 mg/g.The rice varieties or lines with more than 80 mg/g of rice seed storage protein contents were rare,only accounting for 2.7% of the total tested materials.The result of SDS-PAGE for seed storage proteins also displayed obvious polymorphisms among the rice varieties or lines.It could provide useful information for seed storage protein analysis and for rice breeding.

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Effect of Seeding Time on Chalkiness of Liangyoupeijiu in Jiangsu Rice Growing Areas at Different Latitudes SHEN Xin-ping ,SHEN Xiao-yan ,GU Li ,GONG Li-ping ,ZHANG Hong-cheng 2007, 21(6): 677-680 .  Abstract ( )   PDF (458KB) ( )   By using five seeding time treatments in four rice growing areas (the latitude ranges from 31.3°to 34.7°N) in Jiangsu Province, China, the characteristics of chalkiness of a twoline midseason indica hybrid rice Liangyoupeijiu were studied. The chalkiness of Liangyoupeijiu was affected significantly by both seeding time and growing areas, the range of chalky grain rate and chalkiness degree were 54.0 and 13.0 percent point, respectively. The chalkiness of Liangyoupeijiu changed distinctly as the changing latitude of growing area, the area fitting for planting Liangyoupeijiu was between Yangzhou and Donghai, with the optimum region from Jianhu to Donghai; the chalky grain rate of Liangyoupeijiu planting in the extreme south and north areas in Jiangsu (Kunshan, Peixian) was higher than that in the middle area distinctly. The chalkiness in each growing area turned better when the seeding time delayed, especially in the north of Jiangsu Province. The daily average temperature at the productive stage had a significantly positive correlation with chalky grain rate and chalkiness degree. Therefore, it could be deduced that delaying seeding time properly would be an effective way to decrease chalkiness of Liangyoupeijiu under the condition of high yield cultivation in Jiangsu Province.