Table of Content

12 April 2007, Volume 33 Issue 04

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REVIEW

Reviews of Association Analysis for Quantitative Traits in Plants

YANG Xiao-Hong;YAN Jian-Bing;ZHENG Yan-Ping;YU Jian-Ming;LI Jian-Sheng

Acta Agron Sin. 2007, 33(04):  523-530. 

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Recently, association analysis has been widely employed to investigate quantitative traits in plant genetics and breeding. Association analysis is an approach to identify the relationship of molecular markers or candidate genes with traits in a given population based on linkage disequilibrium (LD). Here, we introduced the definition and measurements of LD and reviewed the advances of association analysis for the investigation of quantitative traits in plants. The effects of mating systems, such as recombination, genetic drift, and population structure to the patterns of LD were discussed. Finally, we also discussed the potential application of association analysis for dissecting quantitative traits and plant molecular breeding.

ORIGINAL PAPERS

Genotypic Differences in Some Physiological Characteristics during Cotton Fiber Thickening and Its Relationship with Fiber Strength

ZHANG Wen-Jing;HU Hong-Biao;CHEN Bing-Lin;SHU Hong-Mei;WANG You-Hua;ZHOU ZHi-Guo

Acta Agron Sin. 2007, 33(04):  531-538. 

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The secondary wall thickening stage is a key period to cotton fiber strength development and many complex physiological and biochemical processes are involved in it. To investigate the relationship between the genotypic differences in some physiological characteristics during cotton fiber thickening and the fiber strength, we carried out the 2-year experiments in Nanjing, Jiangsu Province (cotton belts in lower basin of the Yangtze River) in 2004–2005 by using three genotypes with significant difference in fiber strength as materials. Flowers were labeled at anthesis and sampling was conducted every seven days from 10 DPA (day post-anthesis) on. The results showed that the genotype Ⅰ with high strength fiber (Kemian 1 was representative cultivar) had more soluble sugar transformed, higher peak of β-1,3-glucan content at the onset of fiber secondary wall thickening. Sucrose synthetase and β-1,3-glucanase, plays very important roles in fiber development, always kept in higher activities in Kemian 1 than in other tested cultivars during the fiber secondary wall thickening. All these resulted in longer term and more tempered cellulose accumulation and higher strength fiber formation. On the contrary, the genotype Ⅱ with lower strength fiber (Dexiamian 1 and Sumian 15 were representative cultivars) had less soluble sugar transformed, lower peak of β-1,3-glucan content at the onset of fiber secondary wall thickening, slower increasing trend of the key enzymes activities and a more quickly descended trend afterward, leading to a shorter term and rapid cellulose accumulation and lower strength fiber. Dexiamian 1, an early cultivar, reached the peak values of β-1,3-glucan content and key enzymes activities earlier than other cultivars for about a week. And the starting time of cellulose rapid accumulation was also earlier than other tested cultivars. The characters of the genotype Ⅲ with medium strength fiber (NuCOTN 33B) were intermediate. From above results, we suggest that the differences of the dynamics of soluble sugar and β-1,3-glucan contents and sucrose synthetase and β-1,3-glucanase might be one of the physiological reasons for the differences in the cellulose accumulation and fiber strength formation. Further, the occurrence of β-1,3-glucan content peak may be proposed as a sign of the onset of secondary wall thickening in the fiber cell.

Responses of Ethylene and ACC in Rice Grains to Soil Moisture and Their Relation to Grain Filling

LIU Kai;YE Yu-Xiu;TANG Cheng;WANG Zhi-Qin;YANG Jian-Chang

Acta Agron Sin. 2007, 33(04):  539-546. 

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The objectives of this study were to measure the contents of ethylene and 1-aminocylopropane -1-carboxylic acid (ACC) in rice grains and root bleeding sap during the grain filling period and the grain filling rate. Using two high lodging-resistant rice (Oryza sativa L.) cultivars grown by pot or tank with these treatments, well watered (WW), moderate soil-drying (MD), and severe water-deficit (SD) from 9 d post-anthesis until maturity. The effects of chemical regulators on the concentrations of ethylene and ACC in the grains were also studied. The results indicated that MD significantly increased, whereas SD significantly reduced, grain-filling rate and grain weight. Concentrations of ethylene and ACC in the grains were very high at early grain filling stage and sharply decreased during the linear period of grain growth. MD reduced, whereas SD remarkably increased, ACC concentrations and ethylene evolution rate. Both the ethylene evolution rate in rice grains and ACC concentrations in root-bleeding sap were significantly and positively correlated with ACC concentrations in rice grains. The ethylene evolution rate was significantly and inversely correlated with grain-filling rate. Application of amino-ethoxyvinylglycine (AVG), an inhibitor of ethylene synthesis, at 9–13 d post-anthesis significantly reduced ACC concentrations and ethylene evolution rate of the grains, whereas significantly enhanced the activities of sucrose synthase, ADP glucose pyrophosphorylase and soluble starch synthase, and the results were reversed when ethephon (ethylene-releasing agent) was applied. The results suggested that a moderate water stress during the grain-filling period of rice could inhibit the production of ethylene and ACC and therefore accelerate grain filling and increase grain weight.

Genome Analysis of Gene Loci Related to Sterility of Two Inter-subspecific Hybrids betwen Indica and Japonica Rice（Oryza sativa L.）

YU Chuan-Yuan;ZHAO Zhi-Gang;CHEN Ping;JIANG Ling;ZHAI Hu-Qu;WAN Jian-Min

Acta Agron Sin. 2007, 33(04):  547-553. 

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The two rice indica/japonica combinations, Asominori/IR24 and 02428/IR24, have strong heterosis, but low seed-setting rates. To understand the genetic bases of the sterility of the two hybrids，a study for identification of gene loci causing hybrid sterility were carried out by using a set of CSSL population with genetic background of japonica variety Asominori and chromosome substitution segments of indica IR24. The results showed that the sterility of Asominori/IR24 is mainly controlled by three gene loci, namely S-5 on chromosome 6, S-24(t) and S-31(t) on chromosome 5, and that of 02428/IR24 is influenced by S-24(t), a locus conferring pollen fertility. S-31(t) was first identified and tentatively nominated, and furthermore, a neutral gene on S-31(t) was also identified in a japonica variety 02428, which had been well documented with a neutral allele S-5n on S-5. The genetic background has a great effect on expression of fertile genes. In the japonica background, S-24(t) at Sⁱ/S^j heterozygous genotype could decrease spikelet fertility by about 70%, but S-31(t) and S-5 were two loci of hybrid semi-fertility. In the heterozygous genetic background of indica/japonica hybrid, the F₁ seed setting rate could be averagely increased by 22.5% when S-5ⁱ/S-5^j genotype replaced with S-5ⁱ/S-5ⁱ, which improved the F₁ fertility near to normal level, but S-24(t) and S-31(t) did not have the significant substitution effects when S-5 was at S-5ⁱ/S-5^j genotype. Therefore, S-5 was proved to be a key locus conferring spikelet sterility of rice indica/japonica hybrids. Finally, an alternative strategy named “alleles substitution method” was put forward to overcome low spikelet fertility in exploiting rice inter-subspecific heterosis.

Isolation and Characterization of Homogentisate Phytyltransferase (HPT) Gene Promoter from Arabidopsis thaliana

ZHU Yong-Xing;WANG Lei;ZHANG Lan;ZHANG Wei;FAN Yun-Liu

Acta Agron Sin. 2007, 33(04):  554-559. 

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Homogentisate Phytyltransferase (HPT) is a key enzyme catalyzing condensation of HGA and PDP in the first step of tocopherol biosynthesis. The HPT gene has been cloned from several photosynthetic organisms. Overexpression of HPT in transgenic plants increases tocopherols significantly in leaves and seeds. A mutation of the Arabidopsis HPT gene results in tocopherol deficiency in the plants. In order to understand the expression pattern of HPT, a 946 bp DNA upstream fragment of the Arabidopsis HPT gene was isolated and transcriptionally fused with the β-glucuronidase (GUS) reporter gene, and the promoter-GUS cussette was introduced into Arabidopsis thaliana by Agrobacterium-mediated transformation. Analysis of transgenic plants using histochemical staining showed that the GUS gene was expressed predominantly in the roots, and also to a lesser degree, in adult leaves, filament and pistil, but not in stems, root tips, anthers, seeds and siliqua. Our results suggested that the HPT gene was predominantly expressed in Arabidopsis roots.

Comparative Physical Mapping of Bph15 with BAC-FISH in O. glaberrima, O. officinalis, and O. latifolia

LAN Wei-Zhen;LIU Zhe-Sheng;LI Gang;QIN Rui

Acta Agron Sin. 2007, 33(04):  560-565. 

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A fluorescence in situ hybridization (FISH) procedure was adopted to physical mapping two BAC clones 20M14 (27 kb) and 64O9 (36 kb) which linked to the brown planthopper resistance gene Bph15, in O. glaberrima Steud., O. officinalis Wall, and O. latifolia Desv. The results showed that 20M14 and 64O9 were both located on the short arm of chromosome 4 in O. officinalis and O. glaberrima. The percentage distances from the centromere to hybridization sites were 37.03±4.11 and 81.22±3.62, the detection rates were 41.18% and 38.22% in O. officinalis and O. glaberrima, respectively. But in O. latifolia, signals were detected on the short arm and centromere area, with the percentage distances of 87.78±5.23 and 0, and the detection rate of 52.58%, respectively. The two BAC clones were syntenic and distributed in the same area of 4S chromosome of O. officinalis and O. glaberrima, and the homologous sequences of Bph15 were detected in DD genome of O. latifolia. Many signals on different chromosomes of O. glaberrima were observed without C_0t-1 DNA blocking, showing that repetitive sequences were also homologous in three species. The comparative physical mapping analysis showed the location of Bph15 in these three species. The relationships among three species in term of the results of location of Bph15 were discussed, and the knowledge of the genetic relationship among different species in genus Oryza is helpful to conservation and utilization of Bph15. The evolutive mechanism of gene function in different genomes, diploid, and tetraploid species is also discussed.

Breeding for PGMS Line by Using eui Gene from Recessive Tall Rice 02428h

WANG Cai-Lin;ZHAO Ling;ZHU Zhen;ZHANG Ya-Dong

Acta Agron Sin. 2007, 33(04):  566-571. 

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Elongated uppermost internode was firstly found in 1981 by Rutger and Carnahan. They named the recessive gene controlling this character as elongated uppermost internode (eui) gene. It is regarded as the forth genetic factor besides CMS line, maintain line and restoring line, improving panicle exsertion and reducing the applying amount of GA₃ in three-line hybrid rice seed production. Since then, several eui mutants have been found. 02428h is one of such resessive tall rice mutants with eui from somaclonal variation of a wide compatibility japonica rice 02428. Pei’ai 64S is a photo- and thermo-sensitive sterile line with stable sterility and good combining ability. It is widely used in rice breeding of two-line hybrid and some super high yielding rice hybrids such as Liangyoupeijiu (Pei’ai 64S/9311). However, its panicle exsertion is not so good and 450–600 g ha-1 GA3 must be applied in its seed production. In order to improve the panicle exsertion of photo- and thermo-sensitive sterile line “Pei’ai 64S”, a breeding program transferring the eui gene into Pei’ai 64S through successive backcrossing was conducted by using eui gene of 02428h in the study. In BC₁F₁ and BC₂F₁, the plant used for backcrossing was self pollinated and harvested for investigating the segregation of eui gene in next generation. A new photo- and thermo-sensitive sterile line “P8hS” with the character of elongated uppermost internode was bred through three generations of successive backcrossing. Compared with Pei’ai 64S, P8hS had no difference in sterility and sterility period. The plant height of P8hS was 35.6 cm higher resulted from the elongation of the uppermost internode and the second internode from the top. The panicle extrusion of P8hS was completely improved with its panicle neck length of 13.8 cm long. The panicle length of P8hS was 2.2 cm longer and the number of spikelets per panicle was 35 more in P8hS than in Pei’ai 64S. The plant height was significantly higher, panicle length and panicle neck length were longer, the number of secondary branches, spikelets and grains per panicle were more in the hybrid of P8hS/9311 than in Pei’ai 64S/9311. The successful breeding of P8hS is of great significance in reducing the cost of seed production, improving the seed quality and decreasing the environmental pollution.

Genetic Difference Changes of Main Restorer and Sterile Lines in Different Stages of Hybrid Rice (Oryza sativa spp. indica L.)

ZHA Ren-Ming;YANG Zheng-Lin;ZHAO Fang-Ming;ZHONG Bing-Qiang;PENG Tao;XIE Rong;HE Guang-Hua

Acta Agron Sin. 2007, 33(04):  572-577. 

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Heterosis of F₁ hybrid is correlative to genetic distance between its parents, the sterile and the restorer lines, at certain extent. Study on genetic diversity dynamics of widely used sterile and restorer lines of hybrid rice (Oryza sativa spp. indica L.) at different stages will help to choose parents efficiently and to improve hybrid yield. In present research, 31 pairs of AFLP (amplified fragment length polymorphism) primers were used to detect genetic distances of 19 restorers and 13 sterile lines of WA-type hybrid rice that were widely used at different stages. All polymorphic bands were recorded by 0/1 method. Genetic distances (GD) of Nei & Li between all possible pairs of parents were calculated using AFLP data. Chi-square genetic distances between parents were calculated based on the standardized values of 15 agronomic traits of 32 parents. 32 rice parents were clustered based on GD values and on Chi-square distances by UPGMA respectively. The results were as follows: (1) A total of 535 clear polymorphic bands were detected among 32 parents, and on average 17.3 distinguishable bands were observed after amplification with each primer pair. (2) The result of dendrogram based on AFLP markers was similar to that on agronomic traits analyses in grouping of 32 parents of sterile and restorer lines, but a few differences between two dendrograms were detected in diversity among sterile or restorer lines. (3) There were relatively larger genetic differences among 32 parents, and the GDs between sterile and restorer lines were larger than those among restorers as well as among sterile lines. (4) The GDs among early-stage restorers were lower than those among middle-stage and late-stage restorers. Similar trend was observed on the GDs between sterile lines and restorers in 3 stages. These trends were positively correlated with the yield trend of hybrid rice, i.e. the yield of hybrid rice was largely improved in the middle-to-late 1980s and was stunted after 1990s. (5) The GDs among late-stage sterile lines were larger than those among early-stage sterile lines, but the GDs between early-stage sterile lines and restorers showed no significant difference from those between the late-stage sterile lines and restorers. (6) The trend of GDs based on AFLP markers of restorers in 3 stages was similar to yield trend of hybrid rice cultivars. GDs based on molecular makers can be used as one reference in choosing restorers in hybrid crossing.

The Difference of Autotoxic Compounds Content in Alfalfa Cultivars

LU Cheng;ZENG Zhao-Hai;ZHENG Shi-Zong;QI Zhi-Qiang;HU Yue-Gao

Acta Agron Sin. 2007, 33(04):  578-582. 

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Autotoxicity restricts the development of alfalfa industry. In North America researchers did some work on this field, but in China little work has been done about it. The objective of this research was to evaluate the differences of autotoxic compounds content in different alfalfa (Medicago sativa L.) cultivars by bioassay and high performance liquid chromatography. The results indicated that alfalfa leaf extracts inhibited the radicel growth of ‘vector’, and the treated radicels of ‘vector’ were shorter than that of control significantly (P<0.01). Fifty cultivars of alfalfa showed difference in aotutoxicity, and were divided into three categories based on the autotoxicity of their leaf extracts. Alfalfa ‘Key’ exhibited the least aotutoxicity, while ‘GS2001X’, ‘Super Apollo’, ‘Archer’, ‘NS00-32’, ‘Muye’, and ‘WL232HQ’ showed strong autotoxicity. Coumarine, o-coumaric acid, m-coumaric acid, and p-coumaric acid were detected in leaf extracts of alfalfa by high performance liquid chromatography.

Improved Contraction-Expansion Algorithm for Curve and Surface Fitting

GU Shi-Liang;WAN Lin-Sheng;HUANG Li-Juan;WANG Wen-Ping

Acta Agron Sin. 2007, 33(04):  583-589. 

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The improved contraction-expansion algorithm was established mainly by combining previous C-E algorithm with Levenberg-Marquardt method based on numerical derivative technique. The new algorithm could use differential information to guide searching direction without providing derivatives, so as to simplify fitting process and raise searching efficiency. The new C-E algorithm greatly reduced computing load for those multiple parameters situation and strengthened the ability to jump out off pitfalls. The feedback system was more sensitive than previous one in using scatter-spread of the spring points to adjust search step length. Improved effects were obtained in fitting various nonlinear equations with new algorithm. Some examples were given to demonstrate the power in curve and surface fitting.

Effects of Nitrogen Strategies on Population Quality Index and Grain Yield & Quality in Weak-Gluten Wheat

LU Zeng-Gen;DAI Ting-Bo;JIANG Dong;JING Qi;WU Zheng-Gui;ZHOU Pei-Nan;CAO Wei-Xing

Acta Agron Sin. 2007, 33(04):  590-597. 

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Improving grain quality based on high yield is still a substaintial target in wheat production. It has been proved that the key factors contributing to high yield are the dry matter accumulation from flowering to maturity, the biomass at maturity, the optimal leaf area index (LAI), and the proper spike rate. These factors also act as the indexes to evaluate wheat population quality. However, the optimal population quality indexes vary in different specific wheat populations, and optimal cultivating techniques are unavailable due to lack of reliable population regulation indexes in weak-gluten wheat practice. It is very important to establish the optimal population quality index and develop corresponding nitrogen fertilization strategy for high-quality and high-yield production in weak-gluten wheat. In the present study, we employed two weak-gluten wheat cultivars, Yangmai 9 and Ningmai 9, to investigate the effects of nitrogen rates (0, 60, 120, 180, 240, and 300 kg ha^-1) and dressing ratios (8:2, 7:3, 6:4, 5:5, and 7:2:1 under nitrogen rate of 180 kg·ha^-1) on population index, grain yield, protein and gluten contents in 2003–2004. The results showed that leaf area index (LAI) at booting increased with increasing nitrogen rates. Grain yield, post-anthesis dry matter accumulation and biomass at maturing were parabolically related to nitrogen rates. The contents of protein and wet gluten in grains were positively correlated with nitrogen rates. While under the same nitrogen rate of 180 kg ha^-1, post-anthesis dry matter accumulation, biomass at maturity, spike number, spike rate, LAI at booting, grain yield, and contents of crude protein and wet gluten were enhanced with increasing dressing percentages, especially with dressing twice with the same percentage. Also, post-anthesis dry matter accumulation, biomass at maturity, spike number and spike rate were significantly correlated with grain yield. LAI at jointing, booting, anthesis and filling showed close relationships with grain yield. The results indicated that grain yield and quality could be improved synchronously under nitrogen rate of 200 kg ha^-1 based on dressing ratio of 7:2:1 in weak-gluten wheat. The corresponding population indexes for high-quality and grain yield in weak gluten wheat were 6.9 of the highest LAI at booting, 5 300 kg ha^-1 of post-anthesis dry matter accumulation, 16 500 kg ha^-1 of biomass at maturity, 466×10⁴ ha^-1 of spike number and 50% of spike rate.

Genetic Diversity and Relationship of Clonal Tea Cultivars in China Revealed by ISSR Markers

YAO Ming-Zhe;CHEN Liang;WANG Xin-Chao;ZHAO Li-Ping;YANG Ya-Jun

Acta Agron Sin. 2007, 33(04):  598-604. 

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Tea is an important beverage crop in China. In recent years many clonal tea cultivars have been developed and widely replaced the diverse traditional tea population. Our knowledge on genetic diversity and relationship of these clonal tea cultivars is critical to guide tea breeding, but still limited. In this study, the genetic diversity and relationship of 36 clonal tea cultivars which mainly cultivated in China were analyzed with ISSR markers. Based on 20 ISSR primers, total 368 bands were generated, of which 367 (99.7%) were polymorphic. The average polymorphism information content (PIC) was 0.90, Nei’s gene diversity (H) and Shannon’s information index (I) were 0.23 and 0.38, respectively. Diversity of clonal cultivars within tea area was lower than that of in whole nation. The levels of diversity in Tea Area of Jiangnan and South China were higher than those of Southwest China. Analysis of molecular variance (AMOVA) showed that variance component among cultivars (94.4%) was far higher than that among regions (5.6%). The genetic similarity among all the tested clonal cultivars ranged from 0.58 to 0.84, averaging 0.69, which indicated that the genetic basis was relatively narrow. The cluster analysis based on ISSR markers revealed that cultivar “Jinxuan” from Chinese Taiwan was of the farthest distance with others from Chinese mainland in the dendrogram. Thirty-five clonal cultivars from Chinese mainland were clustered into a major group, and they could be further classified into three sub-groups except cultivar “Yihongzao”. The genetic relationship of all 36 tea cultivars revealed by the ISSR dendrogram would be of great help to accurately select the parents in tea breeding programs.

Identification and Analysis of Four Novel Molecular Markers Linked to Powdery Mildew Resistance Gene Pm21 in 6VS Chromosome Short Arm of Haynaldia villosa

WANG Zhen-Ying;ZHAO Hong-Mei;HONG Jing-Xin;CHEN Li-Yuan;ZHU Jie;LI Gang;PENG Yong-Kang;XIE Chao-Jie;LIU Zhi-Yong;SUN Qi-Xin;YANG Zuo-Min

Acta Agron Sin. 2007, 33(04):  605-611. 

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The Pm21 gene, originating from Haynaldia villosa (6AL/6VS), is one of the effective powdery mildew resistance genes. It was observed from chromosome analysis and resistant testing to powdery mildew that Pm21 on 6VS could be stably inherited when transferred to wheat. It is valuable for identification of the molecular markers linked to wheat powdery mildew resistance gene Pm21 in marker-assisted selection in wheat breeding practice. In this study, wheat-Haynaldia chromosome substitution line (6A/6V), translocation lines (6AL/6VS, 6DL/6VS) were used to identify molecular markers located in chromosome short arm 6VS by using RAPD, AFLP techniques, and to investigate the relationship between the molecular markers and Pm21. RAPD test indicated that a Haynaldia villosa chromosome 6VS-specific polymorphic DNA segment OPK08910 was amplified in 6A/6V substitution line, 6AL/6VS and 6DL/6VS translocation lines of wheat-H. villosa. AFLP analysis showed three H. villosa chromosome 6VS-specific polymorphic DNA sequences (264 bp, 218 bp, and 232 bp) could be amplified by three AFLP primer pairs, PstⅠ+AGG / MseⅠ+CAC, PstⅠ+ACC / MseⅠ+CCT and PstⅠ+AAG / MseⅠ+CGC in substitution line (6A/6V), translocation lines (6AL/6VS and 6DL/6VS) and H. villosa (VV). These AFLP markers of PstⅠ+AGG / MseⅠ+CAC-264, PstⅠ+ACC / MseⅠ+CCT-218 and PstⅠ+AAG / MseⅠ+CGC-232 which derived from 6VS, were found to be cosegregated with powdery mildew resistance gene Pm21. These molecular markers can be used as novel DNA markers for selecting powdery mildew resistance gene Pm21 in wheat breeding program.

Establishment and Test of LAI Dynamic Simulation Model for High Yield Population

ZHANG Bin;ZHAO Ming;DONG Zhi-Qiang;LI Jian-Guo;CHEN Chuan-Yong;SUN Rui

Acta Agron Sin. 2007, 33(04):  612-619. 

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Leaf Area Index (LAI) simulation models is an indispensable tool for supporting crop scientific research, population and community growth analysis, and crop management. However, LAI is very difficult to be quantified properly, owing to ecological and varietal factors and temporal variability. Many methods have been developed to quantify LAI and yielded good results, but most of them have different formats with many parameters, which hamper their application. In this paper, an extensively suitable LAI simulation model, y= (a+bx) / (1+cx+dx²), was developed with normalized LAI and crop growth duration data. And by means of which, the specific normalized models y= (0.0134+0.3234x) / (1－2.774x+2.4178x²) for spring maize (r=0.9858**), y= (0.0777+0.0205x) / (1－2.7374x+2.0484x²) for rice (r=0.9865**), and y= (0.0131+0.0035x) / (1－2.4515x+1.5273x²) for winter wheat (r=0.9719**) were established. Compared with other LAI simulation models, normalized LAI dynamic model can not only generate reliable prediction for the evolution of LAI, but also estimate leaf area duration (LAD) and LAI in any period. Once the crop life span and a total leaf area of a crop population in any moment are acquired, the crop LAI and LAD can be estimated easily. From the time of jointing stage, the model could make a good pre-estimation of LAI dynamics with the accuracy of 1.050, 1.0357, and 1.1168 and the precision (R²) were 0.8728, 0.9270, and 0.9254 for spring maize, rice and winter wheat, respectively. Compared with the measured values, the simulated LAI had a linear coefficient (k) over 0.98, with R² above 0.86. The results showed that normalized LAI dynamic model provided a better description for crop population dynamics. Combined with dry matter accumulation, the average LAI, NAR (net assimilation rate), and CGR (crop growth rate) can be calculated. By means of which, the relationships between the physiological parameters and crop yield were analyzed, and the possible ways for higher crop yield were put forward accordingly.

Spatial Variability and Its Statistical Control in Field Experiment

HU Xi-Yuan;Joachim SPILKE

Acta Agron Sin. 2007, 33(04):  620-624. 

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Spatial variability often exists among field experimental units because of many factors, such as moisture, fertility, pH, and structure of soil, and the pressure of diseases and pests. Spatial variability can be dealt with in one of two ways: either though designs, by blocking to account for spatial effect, or though statistical adjustment, by nearest neighbor or trend analysis. Recently, models with spatial covariance structures such as those used in geostatistics have been proposed to account for spatial variability of field experiments. The objectives of this study were to investigate the spatial variation of field experiment, to compare the performance of spatial correlation models with classical variance analysis models, and to investigate the influence of spatial covariance structure selection on data analysis, based on fitting and analyzing yield data of 3 trails using wheat and corn varieties. The results showed that the spatial variation significantly existed in all trails; the spatial variation variance amounted to 83.5%–70.4% of the residual variation variance. Compared with classical randomized complete block analysis, the spatial correlation model analysis reduced standard error of effect contrast by 18.4%–14.2%, its average relative efficiency was 1.50–1.36, hence, it was more effective than the blocking in controlling the spatial variation. The results from different spatial correlation models were not identical. The spatial correlation model and selection of the optimal model using Akaike’s information criterion (AIC) are suggested for analysis of field experiments.

Yield Potential and Water Requirement of Aerobic Rice in Beijing Analyzed by ORYZA2000 Model

XUE Chang-Ying;YANG Xiao-Guang;DENG Wei;ZHANG Tian-Yi;YAN Wei-Xiong;ZHANG Qiu-Ping;ROUZI Aji;ZHAO Jun-Fang;YANF Jie;Bouman B A M

Acta Agron Sin. 2007, 33(04):  625-631. 

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With the decreasing of available water in agriculture, water consumption in rice production has to be reduced and water utilization efficiency increased. Irrigated aerobic rice is a new system being developed in lowland areas with water shortage and in favorable upland areas with access to supplementary irrigation. Domestic and foreign researchers have started studying this new aerobic rice system. In this study, yield potential and water requirement of aerobic rice in Beijing region were obtained by using ORYZA2000 model as well as historical weather data from 1971 to 2000. ORYZA2000 model for simulating the growth of aerobic rice were validated by using field experiment results in Beijing. In this study, ORYZA2000 model was evaluated once more for simulating water requirement of aerobic rice. Results showed that ORYZA2000 model could present water requirements of aerobic rice for the whole growth season satisfactorily with RE (relative error) ranging from 13.0% to 21.5%, which mainly resulted from simulation inaccuracy at the stage of emergence to PI. For the 30 years, averaged yield potential was 8 573 kg hm^-2 shifting from 6747 to 11278 kg ha^-1, interannual variation coefficient of yield potential was 16.3%, while averaged rainfed yield was only 4 048 kg ha^-1 varying from a very low level of 223 kg ha^-1 to even 8 018 kg ha^-1. Therefore, the variation among years was very large with the coefficient of 51.1%. The variations of rainfed yield were mostly related to the rainfall among years. The gap between rainfed yield and yield potential indicated that yield of aerobic rice in Beijing region still could be increased to some extent by supplementary irrigation. Averaged rainfall of the 30 years during the growth season was 486 mm, and it was not enough to meet the water requirement of aerobic rice, which is 712.7 mm with 8.5% variance calculated from ORYZA2000 model. Water shortage was serious in most years, and there were 15 years from 1971 to 2000 in which water shortage was higher than 250 mm, indicating the yield of aerobic rice could be increased by supplementary irrigation. Most of water was consumed at the stage from emergence to panicle initiation, which is the longest duration in the whole life of rice; so much water could be saved if some measures were taken to reduce soil evaporation at this stage. Mean water requirement density for the whole season was 5.3 mm d^-1, while the highest value, 5.5 mm d^-1, occurred at the stage from panicle initiation to flowering.

Agrobacterium-Mediated Transformation of Upland Cotton Simian 3

WU Shen-Jie;LI Fei-Fei;CHE N Tian-Zi;ZHANG Jie;GUO Wang-Zhen;ZHANG Tian-Zhen

Acta Agron Sin. 2007, 33(04):  632-638. 

Abstract ( 1949 )   PDF (3756KB) ( 1106 )   Save

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Simian 3 is one of major cultivars at the cotton-growing district in Yangtze River Valley in the 1990s. New breeding materials or varieties can be rapidly developed through direct transformation of exogenous genes. In this study, we generated transgenic plants from hypocotyl segments of Simian 3 by Agrobacterium-mediated transformation. The rates of callus induction and differentiation were higher in Simian 3 than those in Coker 312. And the major callus morphological characters of Simian 3 from which differentiation center could be formed differed from Coker 312. Histochemical GUS (β-glucuronidase) assay and PCR for nptⅡ (neomycin phosphotransferase) gene were carried out with the transgenic embryogenic callus and leaves of transgenic plantlets. The plantlets proved by histochemical GUS assay and PCR for nptⅡ were grafted and then cultivated in greenhouse. The application of kanamycin at the level of 2 063.98 μmol L^-1 and Southern blot also proved that the target gene was successfully integrated into the genome of Simian 3.

Development and WSSMV Resistance Identification of Wheat Landrace Huixianhong Alien Chromosome Lines Derived from Rye Cultivar Jingzhouheimai

LI Ai-Xia;QI Zeng-Jun;PEI Zi-You;ZHUANG Li-Fang;FENG Yi-Gao;WANG Xiu-E

Acta Agron Sin. 2007, 33(04):  639-645. 

Abstract ( 2049 )   PDF (8208KB) ( 1104 )   Save

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Wheat Spindle Streak Mosaic (WSSM) is an important virus disease mediated by soil bacterium Polynyxa graminis in China. Development and utilization of resistant cultivars is an effective way to control this disease. At present, several cultivars with WSSMV resistance have been grown in these regions, however, most resistance genes are originated from wheat species and show less diversity. Therefore, it is necessary to transfer new genes into wheat, especially from wheat relatives.
After multi-year evaluation, Chinese rye cultivar, Secale cereale cv. Jingzhouheimai, showed high and stable resistance. In order to transfer the genes into wheat, we identified the F₇ to F₉ generations of hybrid derived from Huixianhong (a susceptible wheat landrace from Henan Province, China) and Jingzhouheimai by molecular cytogenetics, molecular markers combined with disease resistance and developed five disomic addition lines (1R, 2R, R3, 5R and R7), one 5RS ditelosomic addition and two multiple addition and substitution lines with chromosome constitution 20’’+2R(2D)’’+4R’’ and 19’’+1R(1B)’’+2R(2B)’’+4R’’, respectively. The resistance identification showed that amphiploid Jinghui 1 had high and stable resistance to WSSMV, which is similar to Jingzhouheimai, indicating regular expression of rye resistance gene(s) in wheat. 2R and R7 disomic additions and 2 multiple addition and substitutions involving 2R showed similar resistance to Jinghui 1，we deduced that chromosomes 2R and R7 from Jingzhouheimai might confer WSSMV resistance. These alien chromosome lines might be useful germplasms in genetic study and breeding wheat for WSSMV resistance.

Application of Electronic Probe on Element Content Measurement in Plant Leaves and Microzone Analysis

LI Mao-Teng;FU Chun-Hua;LIU Jian-Min;LI Qiang;LI Wei;LI Tao;YU Long-Jiang

Acta Agron Sin. 2007, 33(04):  646-651. 

Abstract ( 1760 )   PDF (15519KB) ( 1517 )   Save

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The element analysis is most important in agriculture production. There are many methods for analyzing the element content, which are complicated in sample-treatment and cannot be used for analyzing the element content in the leaf surface microzones. The electronic probe method one with the merits of simple pre-treatment without sample destruction and the analyses of the element content and their distribution in microzones which made it is widely used in metallurgical, geological, archeological fields. In this paper, we analyzed the element composition and contents in soil and mesophyll cells of four species of plant by using electronic probe. The results showed that the element composition and contents in mesophyll cells could be well measured through this method. The elemental contents in mesophyll cells were not certainly correlated with those in the soil, which indicated that the elements absorption of plants was determined by its heredity and also affected by the element content of the soil. The linear scanning method can be show the element content in every scanning point along the restricted line, the results indicated that the element content was varied a lot in the different scanning points of leaves. The map scanning technique also could demonstrate the element content and their distribution in a particular region, for example, in the particle structure of leaf surface of B. napus. In conclusion, the electronic probe technology can be effectively used in analyzing element content in microzone of plant leaf surface.

Quantitative Analysis and Primary Simulation on Rice Panicle Structure

SHI Chun-Lin;ZHU Yan;TANG Liang;CAO Wei-Xing

Acta Agron Sin. 2007, 33(04):  652-656. 

Abstract ( 2048 )   PDF (502KB) ( 1139 )   Save

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Visual simulation on crop architecture can help readers to better understand crop growth processes and analyze the relationship between architecture and function. Panicle of rice is the critical organ for yield formation. Its architecture depends deeply on ecological environment and cultivation methods, and most crop growth models on rice can simulate the effect of ecological environment and cultivation methods on yield components, such as panicle number, grain number per panicle, seed-setting percentage, 1000-grain weight, and number of primary branch. Therefore combination with the outputs of crop growth model, developing architecture model will improve its applicability. On the field experiments with different cultivars and nitrogen applications, we analyzed the quantitative characteristics of panicle architecture. The results were as follows: The ratio of primary branch to panicle in length could be characterized by a quadratic equation expressed in terms of nodal number of branch on panicle axis; and these was a linear relationship between the number of secondary branch and the length of primary branch; the primary branch grew uniformly on panicle axis and the nodal distances of primary and secondary branch also had no significant difference. Furthermore, based on the stability of spikelet number of primary branch and secondary branch, the outputs of growth model, such as grain number per panicle and the number of primary branch, were used to analyze total number of secondary branch per panicle and its space distribution. Thus panicle architecture could be described clearly. Then the model of total number of secondary branch per panicle and panicle architecture were validated with independent data. The results indicate that the simulated values of total number of secondary branch per panicle are accordant with the observed values, and the simulated panicle architectures are similar with the observed. Panicle architecture can be simulated visually under different conditions.

Developing Molecular Markers for Leaf Rust Resistance Gene Lr45 in Wheat Based on SSR

ZHANG Na;YANG Wen-Xiang;Li Ya-Ning;ZHANG Ting;LIU Da-Qun

Acta Agron Sin. 2007, 33(04):  657-662. 

Abstract ( 2169 )   PDF (4897KB) ( 1157 )   Save

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Wheat (Triticum aestivum L.) leaf rust, caused by Puccinia triticina (formerly P. recondita f. sp. tritici), is one of the most destructive diseases on wheat production throughout the world. The exploitation of markers and locations of leaf rust resistance (Lr series) genes will facilitate marker-assisted selection, and benefit the breeding of effective leaf rust resistant cultivars and the gene cloning. Lr45 is a resistant gene against wheat leaf rust disease originated from Secale cereale and is located on the chromosome 2A. No virulent isolate to the gene has been found to date. SSR are abundant, highly polymorphic, evenly distributed over the genome, and required only small amounts of genomic DNA for analysis. Therefore, it is highly suitable for genetic markers in wheat for mapping agronomically important genes. And it provides a robust tool for verification and localization of wheat target genes. In this study, SSR markers were employed to tag the gene Lr45 and four NILs (TcLr11, TcLr17, TcLr37, and TcLr45), the original parent Secale cereale, the susceptible line Thatcher and 157 individuals of F₂ progeny derived from a cross between TcLr45 and Thatcher were used to marker gene Lr45. The wheat seedlings of parents and F₂ generation were inoculated solely with leaf rust spora, and cultured in greenhouse. At the 14th days after inoculation, infection type of all plant materials were scored in six grades with Roelfs’s system. Genomic DNA of wheat was extracted by CTAB. Fifty-nine SSR and EST-SSR primer pairs located on wheat chromosome 2A were screened, and the PCR-amplified products were either checked on 3% agrose gel or on a denaturing 6.0% poly-acrylamide gel. Eleven primer pairs displayed polymorphism of TcLr45 and four SSR markers (Xgwm95, Xgwm47, Xgwm372, and Xgwm122) co-segregated with Lr45 were acquired. Xgwm95 gave difference bands in F₂ populations, and Xgwm47 have a resistance band of 133 bp. Resistance and susceptibility sequenced marker Xgwm95, resistance sequenced Xgwm47 showed that they include repeats of di-nucleotide. Xgwm372 and Xgwm122 gave a specific resistance band of 180 bp and 110 bp respectively, also in Secale cereale, the original parent of Lr45. They can be used in MAS directly. No EST-SSR marker for Lr45 was acquired in this study.

Development and Evaluation of Two Link-up Single Segment Introgression Lines (SSILs) in Zea mays

WANG Li-Qiu;ZHAO Yong-Feng;XUE Ya-Dong;ZHANG Zu-Xin;ZHENG Yong-Lian;CHEN Jing-Tang

Acta Agron Sin. 2007, 33(04):  663-668. 

Abstract ( 2068 )   PDF (14541KB) ( 1296 )   Save

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Currently, a widely adopted strategy to estimate the position and effect of a mapped QTL more accurately is to create a new mapping population by crossing nearly isogenic line (NIL). In such a population, because of the absence of other segregating genetic background, the target QTL becomes the major genetic source of variation. Under such conditions, the QTL is considered as Mendel factor, and the distances between a QTL and the nearby molecular markers can be estimated more precisely. However, as a premise to perform the strategy, NILs that differ only at a short chromosome segment harboring QTL must be produced by marker assisted backcross introgression of one QTL allele into one or both parental genetic backgrounds. To develop two set of NILs covering whole genome of maize respectively, 87-1 and Zong 3(two parental lines of an elite maize hybrid Yuyu 22), and Hengbai 522(a waxy corn line derived from a local variety with short plant stature and disease resistance), were employed in the study. Two populations of link-up single segment introgression lines (SSILs) were developed with 87-1 and Zong 3 as the recurrent parents, Hengbai 522 as donor, respectively through 3–4 cycles advanced backcross. Foreground and background of populations were screened by SSR markers in each cycle of backcross. Genetic evaluation showed that 40 and 78 segments from the donor line were introgressed into 87-1 and Zong 3 SSILs, respectively. In population of 87-1 SSILs, the average length of a single introgressive segment was 91.1 cM, varying from 0.03 to 342.8 cM. The total segment length was 3 643.9 cM with coverage of 48.9% of chromosomes. In population of Zong 3 SSILs, the largest segment was 343.4 cM with an average and a total length of 75.5 cM and 5895.2 cM, respectively, and with the coverage of 79.2% of chromosomes. These developed SSILs could be widely used in fine mapping of QTLs and functional genomics researches of maize.

Accumulation Characters of Biomass and Nitrogen and Critical Nitrogen Concentration Dilution Model of Cotton Fruit-branch Leaf after Flowering

XUE Xiao-Ping;WANG Jian-Guo;GUO Wen-Qi;CHEN Bing-Lin;WANG You-Hua;ZHANG Li-Juan;ZHOU Zhi-Guo

Acta Agron Sin. 2007, 33(04):  669-676. 

Abstract ( 1934 )   PDF (1017KB) ( 1021 )   Save

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Several field experiments with different levels of N application (0, 120, 240, 360, and 480 kg ha^-1) were performed to investigate the responses of cotton growth and lint yield to a range of applied nitrogen treatments in Nanjing and Anyang, standing for the ecological conditions in the middle lower reaches of Yangtze River Valley and Yellow River Valley in China, respectively, and provide information better assessing the requirement of nitrogen and improving the fertilizer-nitrogen use efficiency for cotton. We established a model for cotton fruit-branch leaf and investigated its relationship with yield based on Justes, a critical nitrogen concentration dilution curve, which can be defined as the minimum nitrogen concentration required for maximum growth rate at any time. The results indicated that the biomass and nitrogen accumulation were greatly affected by nitrogen level for cotton fruit-branch leaf, and exhibited a sigmoid behavior when expressed as a function of time. The beginning time of fast accumulation period for nitrogen was 2–4 days earlier than that for biomass. The cotton lint yield was correlative with nitrogen concentration in fruit-branch leaf, which would cause the lint yield reduction when it was lower or higher than critical nitrogen value in fruit-branch leaf. Therefore the phenomenon of nitrogen luxurious consumption existed for fruit-branch leaf of cotton after flowering. The nitrogen concentration in fruit-branch leaf increased with the increasing of applied N rates, and decreased in the growing process. The relationship between the nitrogen concentration and dry matter of fruit-branch leaf can be described by a power equation. The patterns of nitrogen concentration dilution model were consistent at both experimental sites, but with different values for parameters. Therefore, the results presented in this paper backup the viewpoint that a critical nitrogen concentration dilution curve for cotton fruit-branch leaf is independent of ecological region. The maximum and minimum nitrogen concentration dilution curves can also be described with power equation, and are independent of ecological region. Relationships between total nitrogen accumulation and accumulated dry matter in fruit-branch leaf fit very well to the model Nupt=10 aW 1－b for each nitrogen fertilization level at two experimental sites. The cotton fruit-branch leaf in Anyang had a higher capacity of nitrogen accumulation than that in Nanjing for the same dry matter. The lower position of the critical nitrogen concentration dilution curve for the same fruit-branch leaf biomass in Nanjing indicated that the nitrogen biomass productivity was higher than that in Anyang. Because of having the biological sound for the critical N concentration dilution curve, it can be a reliable tool for diagnosing the nitrogen nutrition status of fruit-branch leaf. Therefore, the diagnosises made by the models of allometry and nitrogen nutrition index (NNI), which based on the critical nitrogen concentration dilution model, had a sound biological basis. According to the allometric coefficient, NNI and dynamic nitrogen accumulation rate under critical nitrogen concentration, the optimal rate applied nitrogen fertilization in Anyang which was 240–360 kg ha^-1 and more does to 360 kg ha^-1 should be higher than that in Nanjing which was 240 kg ha^-1.

RESEARCH NOTES

Effects of High Temperature and Shading Stress after Anthesis on Endogenous Hormone Contents and Filling Process in Wheat Grain

LIU Xia;MU Chun-Hua;YIN Yan-Ping;JIANG Chun-Ming;WANG Zhen-Lin

Acta Agron Sin. 2007, 33(04):  677-681. 

Abstract ( 1934 )   PDF (486KB) ( 1021 )   Save

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The overcast, rainy, weak light or preternatural high temperature weather, which badly affects the grain weight, frequently occurs after anthesis. Previous studies have indicated that the effects of ecological factor on wheat grain weight were realized by changing the endogenous hormone contents. While little information is available on grain filling process and endogenous hormone contents under high temperature and light stress after anthesis of wheat. Therefore, effects of high temperature, shading stress and double stress of them after anthesis on grain filling process and endogenous hormone contents of wheat were investigated. Compared with CK, all stress treatments obviously reduced kernel weight and the effect of double stress of high temperature and shading at metaphase on kernel weight was the most significant. The decline of single kernel weight was mainly caused by the decrease of slight-increase period filling rate and mean filling rate, and not by filling duration, which had a little effect on kernel weight. The changes of mean filling rate, maximum filling rate, slow-increase period filling rate, fast-increase period filling rate and slight-increase period filling rate were attributed to a decrease of GA₃ or increase of ABA in the grains during grain filling. The correlations among changing rates of endogenous hormones indole-3-acetic acid (IAA), gibberellin (GA₃), zeatin riboside (ZR), and abscisic acid (ABA) as well as mean filling rate in grain were analyzed. The results showed that the grain filling rate was mainly regulated at the early grain filling stages (7 to 12 days after anthesis) and late grain filling stages(19 to 28 days after anthesis) by GA₃ and at middle grain filling stages(12 to 19 days after anthesis) by ABA. The correlation of the mean filling rate with ABA was closer than that with GA₃. No significant correlation was found between grain filling rate and the changes of ZR or IAA content during the whole grain filling period.

Characterization of Starch Accumulation and Activities of Enzymes Involved in Starch Synthesis in Grains of Wheat Cultivars Differing in Spike Types Field-Grown in Irrigation and Rainfed Conditions

DAI Zhong-Min;WANG Zhen-Lin;GAO Feng-Ju;LI Wen-Yang;YAN Su-Hui;CAI Rui-Guo;ZHANG Min;YIN Yan-Ping

Acta Agron Sin. 2007, 33(04):  682-685. 

Abstract ( 2053 )   PDF (454KB) ( 1041 )   Save

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The study was carried out to characterize the starch accumulation and activities of some key enzymes in big-spike type cultivars, SN710331 and VM8, and poly-spike type cultivars, LM21 and JN17, under irrigated and rainfed conditions. Results showed that starch accumulation rate (SAR) and activities of SS, AGPase, SSS, GBSS, and SBE in big-spike type cultivars were significantly higher than those in poly-spike type cultivars. The soil water deficit led to the increases at early grain-filling period and decrease during late grain-filling, respectively, in SAR, accumulation duration and activities of the key enzymes above. Water deficit enhanced grain starch accumulation in poly-spike type cultivars. The simulation with Richards equation showed that starch accumulation duration and SAR determine the starch accumulation amount. The grains of big-spike type cultivars maintained longer filling duration, higher SAR and greater activities of related enzymes than those of poly-spike type cultivars during mid and late grain-filling.

Genetic Control Analysis of Barley (Hordeum vulgare L.) Anther Culture Response

HE Yu-Chi;GE Jie;TAO Cai-Cheng;WANG He-Qing;CAI De-Tian

Acta Agron Sin. 2007, 33(04):  686-688. 

Abstract ( 1846 )   PDF (302KB) ( 949 )   Save

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Genotype difference and combing ability of barley anther culture response was investigated by the way of circulated partial diallel crossing. The result suggested that the difference between genotypes in anther culture response was significant. On the anther culture response of genotypes, the general combing ability (GCA) and special combing ability (SCA) were independent each other, and both significantly different at 0.01 probability level. The genetic basis of anther culture response was controlled by dominance effect and additive effect, additive effect was more important than dominance effect. GCA would play critical roles in increasing the frequency of callus formation from anthers. It was indicated that parents with high SCA could be selected to use in the barley haploid breeding on the basis of the high GCA. Some parents with low callus induction rate could be improved by crossing breeding.

Effect of Triticum spelta 1BS Chromosome on Pollen Development of K-Type Male Sterile Lines of Wheat

MA Ling-Jian;Gong Hong-Wei;HE Bei- Ru;SONG Xi-Yue;HU Yin-Gang

Acta Agron Sin. 2007, 33(04):  689-692. 

Abstract ( 1797 )   PDF (5633KB) ( 890 )   Save

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The content of MDA, membrane permeability, SOD activity and developmental morpha of pollens during the pollen development in non-1B/1R and 1B/1R male sterile lines and their maintenance lines were analyzed. The results showed that the content of MDA and conductivity of pollen extract in two types of wheat sterile lines had nearly the same increasing tendency from meiophase to pollens diverging stage; whereas their maintenance lines had no remarkable difference between each other and these two indexes remained stable during the whole course of pollen development. SOD activity of both types of sterile lines showed a downtrend from uninucleate stage to trinucleate stage. The SOD activity was higher in both sterile lines than in their respective maintenance lines from uninucleate stage to binucleate stage; and that was lower in both sterile lines than in their respective maintenance lines at trinucleate stage, and that appeared in a continuous downtrend. Therefore, it could be inferred that the abortive processes and stages of the two sterile lines were almost the same; and that the key stages of pollen abortion were from uninucleate to trinucleate. However, from the cytalogical observation we found that pollen morpha was abnormal in non-1B/1R sterile lines at binucleate state but in 1B/1R sterile lines at trinucleate stage,indicating that pollen abortion of non-1B/1RK-type sterile lines was a little earlier than that of 1B/1RK-type sterile lines.

Cloning and Analysis of the Full Length cDNA of SKP1 Gene from Nicotiana tabacum var. samsun NN and Its Expression in E. coli

ZHANG Fu-Yun;BAI Xue-Fang;DU Yu-Guang;ZHANG Yu-Kui

Acta Agron Sin. 2007, 33(04):  693-696. 

Abstract ( 1863 )   PDF (4931KB) ( 1094 )   Save

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To investigate the ability of oligochitosan to affect gene transcription, the messenger RNA (mRNA) differential display technique was applied to the identification and isolation of the genes whose transcription were altered in cultured Nicotiana tabacum (var. Samsun NN) plants treated with oligochitosan. Four differential displayed cDNA were subcloned and confirmed by reverse Northern blot analysis. Then the 3’ end cDNA of gene SKP1 was obtained by sequence, the 5’ end and full-length cDNA of gene SKP1 from Nicotiana tabacum var. samsun NN was cloned using the SMART-RACE technique. BLAST analysis revealed that the sequence of full-length cDNA showed 81% identity to that of Nicotiana benthamiana. Analysis of domains showed there was one predicted Skp1 domain between 4 and 105 amino acids whose E-value is 1.25e-52, so the gene was named SKP1 of Nicotiana tabacum var. samsun NN, and submitted to GenBank (accession number: AY702087). To express protein of the gene, cDNA of SKP1 from Nicotiana tabacum var. samsun NN was ligated with the expression vector pET23b. SDS-PAGE indicated that one fused protein was expressed efficiently. These results are useful for studying the function of SKP1.