Table of Content

12 November 2005, Volume 31 Issue 11

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ORIGINAL PAPERS

Transformation and Identification of BCL and RIP Genes Related to Cell Apodosis into Wheat Mediated by Agrobacterium

YE Xing-Guo;Shirley Sato;XU Hui-Jun;DU Li-Pu;HUANG Yi-Hong;LU Wei-Zhong;Tom Clemente

Acta Agron Sin. 2005, 31(11):  1389-1393. 

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Wheat is a very important crop in China, but its grain production is affected seriously by some fungal diseases such as powdery mildew, rusts, scab and take-all. Especially for the scab, wheat resistance breeding to the pathogen has just made a little progress since the disease was concerned enough by scientists because there is no ideal germplasm in the species. Therefore, it is necessary to transfer some available foreign genes for resistance to scab into wheat by genetic engineering. B-cell leukemia cell line inhibitor, BCL, and ribsome inactive protein, RIP, were reported to be useful in fungal disease control by causing program of cell death or stopping pathogen propagation. Based on such purpose, BCL gene from human and RIP gene from maize were successfully transferred into Yangmai 10 and Bobwhite, Triticum aestivum CV., respectively, by using C58c1 Agrobacterium strain as donor, the wheat immature embryos of four days pre-culture as receptor, and 10－25 mg/L G418 as selection agent. The T0 antibiotics resistant plants were screened by nptⅡ ELISA first (Fig. 3), and transgenic plants were obtained by efficiencies of 1.60% and 1.25% (Table 1), respectively. Then the positive plants were confirmed by Southern blot and Northern blot. Southern result in T₁ generation indicated that the alien genes were integrated into wheat chromosomes by single copy mostly (Fig.3, Fig.4). Northern result in T₁ generation showed that the foreign genes were transcripted into RNA even though gene silence was happened in a very few individuals (Fig.5). The selection gene linked with target gene was also tested in T₁ generation for its genetic analysis by ELISA and PCR. The result showed the segregation ratio of alien genes in T₁ generation was 2.11－2.33∶1, a little bit away from Mendelian inheritance (Table 3). The result also suggested that the aliens could inherit stably from generation to generation. By artificial inoculation of the pathogen, the transgenic plants showed some resistance to scab in artificial climate shelter. Fifteen transgenic lines with less disease percentage of 5.6%－16.1% including BCL-20, BCL-21, RIP-8, and RIP-18 were screened out, and their disease resistance was stronger than sensitive control, Annong 8455, and close to the resistant control, Sumai 3 (Table 2). The resistant lines will be identified further for their potential application in the scab breeding.

ESTs Analysis of Resistance to Soybean Mosaic Virus (SMV) in Soybean at Primary Infected Stage

LIU Chun-Yan; CHEN Qing-Shan; XIN Da-Wei; QIU Hong-Mei; SHAN Da-Peng

Acta Agron Sin. 2005, 31(11):  1394-1399. 

Abstract ( 1945 )   PDF (356KB) ( 1032 )   Save

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Soybean is a major source of edible oil and high-quality protein in the world, but the disease make the yield of soybean lower, even have no harvests. To study the resistance mechanism to soybean mosaic virus(SMV), a soybean line, Dongnong 8143, with resistance to SMV, was used, and a subtractive cDNA library was constructed from soybean leaves infected by SMV No.1 at primary stage with SSH. DongNong 8143 was planted in culture pans. When the plants were at V1 stage, the fully-developed unifoliate leaves were inoculated with SMV No.1, then the sampling from inoculated plants and non-inoculated plants was made once every 24 hours and 8 times totally. Total RNA was extracted with TRIZOL Reagent according to the kit manual. To perform SSH, total RNA was pooled for both uninfected and infected samples. Poly(A)+RNA was purified with the PolyATract® mRNA Isolation Kit. SSH was performed using the PCR-select cDNA Subtraction Kit. SMV infected leaves RNA as the tester and uninfected leaves RNA was used as the driver. The cDNA was then digested with RsaⅠ. The tester cDNA then was subdivided into 2 portions, and each was ligated with a different cDNA adaptor. Two rounds of hybridization were performed. After filling in the ends by DNA polymerase, 2 rounds of PCR amplification were performed using the primers that matched the different adaptors to the 5′ and 3′ ends. cDNA dominantly or specifically expressed in infected leaves was purified using PCR Purification Kit and cloned into pGEM-T easy vector. Colonies were grown on LB-agar plates containing ampicillin and IPTG. As a result, A subtractive plasmid library was constructed by SSH. Two thousands positive clones were acquired. 64 clones were picked up randomly and sequenced, and the results showed that the shortest length of ESTs was 136 bp, the longest length of ESTs was 691 bp, and the average length was 456 bp. 41 ESTs of them had poly(A)⁺ sequence. All ESTs were compared with sequences in unigene database of GenBank with BLASTn and BLASTx algorithm, and 49 ESTs of them had comparatively clear results. ESTs with known function involved in cellular protect of soybean, signal transduction, restrict pathogen growth, system acquired resistance, and housekeeping genes related with photosynthesis, respiration, and protein synthesis, etc. SAR genes were the richest not only in varieties but also in quantity. In the function unknown ESTs, many homologous ESTs are found from other biotic and abiotic-stresses selected cDNA libraries after compared with dbEST in GenBank.

Pyramiding Wheat Powdery Mildew Resistance Genes Pm2, Pm4a and Pm21 by Molecular Marker-assisted Selection

GAO An-Li;HE Hua-Gang;CHEN Quan-Zhan;ZHANG Shou-Zhong;CHEN Pei-Du

Acta Agron Sin. 2005, 31(11):  1400-1405. 

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Pyramiding resistance genes has been supposed as one of the most effective methods for preventing breakdown of major gene conferring resistance to powdery mildew within a short period. It is difficult to select pyramids containing more than two resistance genes by common methods. Marker-assisted selection(MAS) is an ideal technology to select target gene in different genetic backgrounds. Pyramiding resistant genes by MAS has been reported. So far, DNA markers linked to wheat powdery mildew resistance genes had been found. In this study, PCR markers tightly linked or co-segregated with Pm2, Pm4a and Pm21 genes were confirmed to be applicable under different genetic backgrounds, and used to identify Pm2, Pm4a and Pm21 genes in breeding practice. Using these tested markers, a hybrid population with three powdery mildew resistance genes was screened and 100 plants containing Pm2, Pm4a and Pm21 were identified after three-cycle MAS. In addition, dozens of plants with two Pm genes were also obtained. The results of inoculation test indicated that the plants pyramiding Pm21 and other genes showed immunity to powdery mildew, as well as the plants possessing only Pm21. The plants with single Pm2 had lower resistance, while those with Pm4a showed middle resistance to powdery mildew. Notably, the plants with Pm2+Pm4a showed much better resistance than those with single Pm2 or Pm4a. To reduce the cost of MAS, two PCRs were performed in one mixture, in which Pm4a and Pm21 were identified respectively. MAS was compared with phenotypic selection also, from which more comprehensive information was provided.

Effects of Soil Moisture and Nitrogen on Abscisic Acid and Cytokinin Contents in the Aboveground Plant Parts of Rice

CHEN Xin-Hong; LIU Kai; XI Ling-Lin; WANG Zhi-Qin; YANG Jian-Chang

Acta Agron Sin. 2005, 31(11):  1406-1414. 

Abstract ( 1889 )   PDF (450KB) ( 1155 )   Save

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Improvement of grain filling is very important in rice production. Two rice cultivars with high lodging resistance grown in pots and tanks were used to investigate the possibility that a moderate water stress imposed during the grain-filling period of rice might accelerate grain-filling rate, and hormones might mediate this process. Two levels of nitrogen, normal amount (NN) or high amount (HN), were applied at heading. Well-watered (WW) and water-stressed (WS) treatments were imposed from 9 d after anthesis till maturity. Leaf water potentials, grain filling rate, and cytokinins and abscisic acid (ABA) contents in the leaves, stems and grains were determined. The results showed that leaf water potentials of both cultivars were markedly decreased at midday in WS treatments but completely recovered by early morning. In WW treatments, grain-filling rate was decreased by HN, while the grain-filling rate was increased and the grain filling period shortened under both HN and NN by WS treatments. At the HN level, filled grain percentage, grain weight and yield were significantly higher than those under WW, implying that the effect of accelerated grain filling rate outweighed the possible loss of photosynthesis due to the shortened grain filling period when subjected to water stress during grain filling. Zeatin (Z) + zeatin riboside (ZR) contents in the stems and grains were transiently increased at early grain filling stage, reached a maximum at 9－12 d after anthesis, and decreased thereafter. Apposite to the performance of Z + ZR, ABA content in the stems and grains was low and slowly increased at early grain filling stage, then reached the peak value simultaneously with the grain-filling rate. The Z + ZR content was decreased, but ABA content significantly increased in plants, especially in the grains by WS. ABA content in grains was positively and significantly correlated, whereas Z + ZR content in grains was not correlated, with grain filling rate. The activities of sucrose synthase, adenosine diphosphoglucose pyrophosphorylase, starch synthase and starch-branching enzyme were significantly enhanced, and at last grain weight was increased by spraying ABA at low concentration on HN-WW plants at early grain filling stage (9－13 d after anthesis). The results were reversed when fluridone (an inhibitor of ABA synthesis) was applied. In conclusions, grain-filling rate is accelerated by a moderate water stress during the grain-filling period of rice and ABA plays an important regulatory role in the process.

QTL Analysis of Root Traits at the Seedling Stage in Rice under Cold Water Irrigation

HAN Long-Zhi; ZHANG San-Yuan; QIAO Yong-Li; ZHANG Jun-Guo; RUAN Ren-Chao; CAO Gui-Lan; KOH Hee-Jong

Acta Agron Sin. 2005, 31(11):  1415-1421. 

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The quantitative trait loci (QTLs) for root traits, such as root number, the longest root length, the diameter of longest root, root dry weight, ratio of root to seedling at the seedling stage in rice under 12℃ cold water irrigation and natural condition was identified by using F_2∶3 population including 200 individuals and lines derived from a cross of indica and japonica “Milyang23/Jileng1” with microsatellite markers. All of root traits at the seedling stage showed a continuous distribution in F₃ lines, which were quantitative traits controlled by many genes. Seventeen QTLs on chromosome 1, 2, 6, 11 and 12, which associated with root traits at the seedling stage under cold water irrigation were detected, which explained the range of the observed phenotypic variance from 5.8% to 15.2%. Among them, qCDR2 and qCDR11 located on RM263-RM6 of chromosome 2 and RM21-RM206 of chromosome 11, respectively, which associated with the diameter of longest root could account for 15.0% and 15.2% of observed phenotypic variation, respectively. qCRWT2 and qCRWT11 located on RM262-RM263 of chromosome 2 and RM229-RM21 of chromosome 11, respectively, which associated with root dry weight could account for 10.6% and 12.2% of observed phenotypic variation, respectively. These gene action was partional dominance or dominance or over dominance.

Effects of Nitrogen Fertilizer on Nitrogen Use Efficiency and Yield of Rice under Different Soil Conditions

YE Quan-Bao;ZHANG Hong-Cheng;WEI Hai-Yan;ZHANG Ying;WANG Ben-Fu;XIA Ke;HUO Zhong-Yang;DAI Qi-Gen;XU Ke

Acta Agron Sin. 2005, 31(11):  1422-1428. 

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Nitrogen is the indispensable nutrient to rice production. The uptake of nitrogen are affected by varietal characteristics, fertilizer application, soil condition and environment factors. Rational application technique and nitrogen use efficiency for rice in the field have been studied by many scholars, which had a direct effect on high-yield and high-efficiency production of rice. However, all of them were studied under the same soil condition. There have been limited studies on the nitrogen use efficiency and yield under different soil conditions. In fact, the difference of soil condition consequentially results in the difference of nutrient uptake in rice under the same land tillage and management in the same region. Four rice cultivars were used to study the effects of nitrogen fertilizer on nitrogen use efficiency，yield and characters of nitrogen uptake under two soil conditions(sandy and clay soil) in soil culture pool. The results were as follows：(1) Yield of rice in sandy and clay soil was increased by nitrogen application，and that in clay soil was higher than that in sandy soil，but the effect of nitrogen on yield increment was greater in sandy soil than in clay soil. (2) Nitrogen utilization of rice was different under different soil conditions. NHI and PNUE were higher in sandy soil than in clay soil. ANRE，PFP and SNDR were higher in clay soil than in sandy soil. ANUE was varied in different cultivars under different soil conditions. (3) NHI，ANUE，PNUE，PFP and SNDR significantly were decreased with the increment of amount of nitrogen applied under two soil conditions. In sandy soil，ANRE was increased with increasing the nitrogen application and reached the highest value at high nitrogen level. However，in clay soil，ANRE was increased with increasing of the nitrogen application at first，and reached the highest value at medium nitrogen level，then decreased dramatically at high nitrogen level. (4) N uptake rate for rice straw and for rice grain and total N uptake rate for rice were higher in sandy clay soil than in sandy soil，but the difference between them was relatively little. (5) Under different soil conditions，there were significant genotypic differences in effects of applying nitrogen fertilizer on nitrogen use efficiency，yield and characters of nitrogen uptake.

Effects of Sunshine-shading, Leaf-cutting and Spikelet-removing on Yield and Quality of Rice in the High Altitude Region

YUAN Ji-Chao;DING Zhi-Yong;ZHAO Chao;ZHU Qing-Sen;LI Jun-Qing;YANG Jian-Chang

Acta Agron Sin. 2005, 31(11):  1429-1436. 

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There have been a lot of reports on the relationship between source-sink state and yield, milling quality and appearance quality in rice, but few reports on the relationship between source-sink state and the RVA profile of rice starch, as well as the relationship between rice quality and grain filling process in rice in the high altitude region. With a purpose of revealing the substantial base of quality formation in rice, the effects of source-sink state on rice quality and the relationship between grain-filling process and rice quality were studied in this paper. The experiments were conducted in a high altitude region by sunshine shading, leaf-cutting and spikelet-removing treatments. The results were as follows: The milled rice rate was reduced but the head milled rice rate increased by sunshing shading, especially for superior grains(Table 2). Under the sunshine shading condition, the chalkiness degree was varied with cultivars and grain positions. The chalkiness degree was increased by leaf-cutting and reduced by spikelet-removing (Table 3). The amylose content，the value of peak viscosity and breakdown viscosity of RVA profile of rice starch were reduced, but the length of rice gel was elongated by sunshine shading in the two experimental cultivars(Table 4). The source-sink state showed a big effect on the grain filling process (Table 5). The area and the degree of chalkiness were negatively correlated with the final grain weight and positively correlated with the days to maximum grain filling rate. The peak and breakdown viscosity of rice starch were positively correlated with the final grain weight and negatively correlated with the days to maximum grain filling rate(Fig.1). The grain-filling rate, the amount of dry-matter filled and its ratio to total weight during the early filling stage(in 15 days after full heading) had the most effect on rice quality, less effect during the late filling stage(30 days latter after full heading) and the least effect during the middle filling stage(15－30 days after full heading). During the early filling stage, the grain-filling rate, amount of dry matter filled and its ratio to total weight increased, the area and degree of chalkiness decreased and the peak and breakdown viscosity of rice starch increased. While during the late filling stage, the grain-filling rate, amount of dry matter filled and its ratio to total weight were increased, the area and degree of chalkiness increased and the peak and breakdown viscosity of rice starch decreased (table 6). The rice quality is influenced not only by the total amount of grain-filling matter, but also by the grain-filling process. The effect of sunshine shading on rice quality in the high altitude region is not fully similar to that in low altitude regions.

Morphology and Anatomy of the Differentiation of Flower Buds and the Process of Flowering Reversion in Soybean cv. Zigongdongdou

LI Xiao-Mei; WU Cun-Xiang; MA Qi-Bin; ZHANG Sheng; LI Chun-Lin; ZHANG Xin-Ying; HAN Tian-Fu

Acta Agron Sin. 2005, 31(11):  1437-1442. 

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The morphological and anatomical changes during floral development and flowering reversion of Zigongdongdou, a late-maturing and photoperiod-sensitive soybean cultivar, were investigated to identify anatomic characteristics of floral development in soybean. The following photoperiod treatments were conducted to obtain different developmental status and morphological changes: (1) Continuous short days (SD, 12 h); (2) Continuous long days (LD, 16 h); and (3) SD for 13 days and then LD (SD13d-LD). The results showed that Zigongdongdou plants normally bloomed and podded in continuous SD. About 50% of plants in SD13d-LD treatment reversed from reproductive development to vegetative growth, and other plants in this treatment bore short terminal racemes. In continuous LD, all plants kept vegetative status. SD not only promoted reproductive development of soybean plants but increased the appearing rate of leaves as well. In SD treatment, first floral primordia were found in basal axil of plants at Day 3, and the apical meristem began to initiate raceme at Day 13. At Day 19, the terminal flower primordia were first found in apex. At Day 29, plants began to bloom. Plants in the treatment of SD13d-LD kept initiating floral primordia within the first fourteen days after transferred from SD to LD, but the initiating rate was slower and the number of floral primordia was fewer than that in continuous SD. About half of plants reversed to initiate vegetative organs after transferring to LD for 20 days (33 days after emergence). While in continuous LD, the apical meristem only produced leaves. The homology of leaves and floral organs was also discussed in this paper.

Comparative Studies on Quality Characters under Water- and Dry-cultivation in Rice

GUO Yong-Mei; MU Ping; LIU Jia-Fu; LU Yi-Xuan; LI Zi-Chao

Acta Agron Sin. 2005, 31(11):  1443-1448. 

Abstract ( 1728 )   PDF (407KB) ( 1188 )   Save

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Rice is one of the main staple food crops in the world, but rice production almost occupies 70 percent of the total water consumption of agriculture in China. To save water resources, improving rice drought resistance is a major goal in rice breeding, and water-saving rice culture (dry-cultivation) is also with a great potential. Most of the rice quality characteristics are controlled by quantitative genes and also affected by environment. Rice grain quality is different under water- and dry-cultivation environments on which comparative studies are very important for rice breeding and cultivation.
A doubled haploid (DH) population consisting of 116 DH lines developed through anther culture of the F1 hybrid between an upland rice cultivar ‘IRAT109’ and a lowland rice cultivar ‘Yuefu’ was used in this study. The parents and the 116 DH lines were planted in water- and dry-cultivation systems, on the experiment farm of China Agricultural University in 2002. Seeds of parents and 116 DH lines were harvested at maturity, and used to measure the content of crude protein, brown rice percentage, milled rice percentage, head milled rice percentage, amylose content, gel consistency, alkali value, chalkiness, grain length, grain width, and grain length/grain width. All data were analyzed by SPSS software.
The correlation analyses were conducted between quality characteristics in the two cultivated systems. The results indicated that the content of crude protein, head milled rice percentage, gel consistency and alkali value were higher, and chalkiness, grain length and grain width lower in dry-cultivation than in water-cultivation (Table 1). In general, most of characters of rice grain quality were improved in dry-cultivation compared with that in water-cultivation. The content of crude protein, head milled rice percentage, gel consistency and alkali value were more sensitive to water-stress, as compared with amylose content, grain length, grain width and chalkiness. Especially, the content of crude protein was increased by 37.9% or 3.02 percentile in dry-cultivation than in water-cultivation (Fig.1). But brown rice percentage, milled rice percentage and the ratio of grain length/grain width were not influenced by cultural environment. In addition, milling quality characters were affected by the interaction of gene and environment (culture system), but the appearance, cooking and nutrition quality characters mainly controlled by genetic factor. Therefore, the grain quality of the lowland or upland rice cultivars with drought-resistance could be improved under upland condition or dry-cultivation by the cross between lowland rice cultivar with elite grain quality and drought-resistant upland rice cultivar.

QTL Identification of Resistance to Head Smut in Maize

SHI Hong-Liang; JIANG Yan-Xi; WANG Zhen-Hua; LI Xin-Hai; LI Ming-Shun; ZHANG Shi-Huang

Acta Agron Sin. 2005, 31(11):  1449-1454. 

Abstract ( 1831 )   PDF (385KB) ( 1063 )   Save

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Head smut of maize (Zea mays L.) caused by Sporisorium reliana is an important fungal disease in China. Development of varieties resistant to this disease is one of the effective approaches to control the disease. In this study, we mapped and characterized quantitative trait Loci (QTL) conferring resistance to head smut. A genetic linkage map with 84 SSR and 48 AFLP marker loci were constructed based on a maize (Zea mays L.) population consisting of 191 F₂ individuals from the cross Mo17×Huangzao4. The linkage map spans maize genome 1 542.9 cM with average interval of 11.7 cM between adjacent markers. The corresponding 184 F₃ families (7 missed) were evaluated for head smut resistance with two replications in Gongzhuling, Jilin province and Harbin, Heilongjiang province under artificial inoculation with chlamydospore, respectively. Quantitative trait Loci (QTL) were detected using composite interval mapping. In Gongzhuling, 5 putative QTL conferring resistance to head smut were detected on chromosomes 1, 2, 3, 8 and 9, respectively, accounting for 10.0% to 16.3% of the phenotypic variance. In Harbin, 5 putative QTL for resistance to head smut were found on chromosomes 1, 2, 3, 4 and 7, respectively, accounting for 4.6% to 13.4% of the phenotypic variance. The QTL with high LR values could be consistently identified on chromosomes 2 and 3 over two environments, displaying over-dominant and additive effects, respectively. These results provided important information for germplasm improvement of heat smut resistance in maize.

The Effect of Chemical Hybridizing Agent EXP on Oilseed Rape

YU Cheng-Yu; HU Sheng-Wu; ZHANG Chun-Hong; YU Yan-Jun; HE Pei-Ru

Acta Agron Sin. 2005, 31(11):  1455-1459. 

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A large number of chemicals capable of selectively inhibiting pollen development have been identified as chemical hybridizing agents(CHA) for large-scale commercial production of hybrid seeds in various crops. Some commercial CHAs such as methyl arsenate (Gametocide No.1 and No.2) have been successfully used to produce commercial hybrid in oilseed rape in China. However, researchers of hybrid breeding are still attempt to develop novel efficient CHAs without environmental and toxic effects. In the present paper, the effect of a new CHA developed by the authors, named EXP, on inducing male sterility of oilseed rape and on the change of the content of pigments (chlorophyll and carotenoid) and soluble protein and the activity of peroxidase and esterase isozyme in treated plant was investigated. Plants of Brassica napus breeding line L82089, Brassica juncea breeding line L638 and Brassica campestris variety Qinyou No.4 were treated with various concentrations of EXP in peduncle-growing period with 1 mm-2 mm long flower bud. All the treatments with EXP were found to be quite effective in inducing pollen sterility. The percentage of sterility and hybrids between treatment and control were significantly different for all doses. The treatments with 12－15 mL of 0.05 μg/mL and 0.25 μg/mL EXP per plant on Brassica napus breeding line L82089 caused about 92% and 97% sterile plants respectively. The plants treated with 0.25 μg/mL EXP were sterile steadily with 6.6% selfing rate (Table 1 and Table 2). So the treatment with 12－15 mL of 0.25 μg/mL EXP could be recommended for producing hybrid in Brassica napus. The development of vegetable and reproductive organs was all suppressed due to the spray of EXP. The induced sterile plants were distinctly characterized by fading leaf, shorter plant height, serried bud, later flowering, fading petal, and shriveling anther with no pollen. The morphology between male sterile and fertile flowers was so different that the treated and untreated plants could be easily discriminated. The content of chlorophyll and carotenoid in the flower of induced sterile plant was decreased (Fig.1). In treated stamen, the activity of peroxidase and esterase isozyme was diminished and the content of soluble protein was very low (Fig.2). Simultaneously, the treatment with 5 mL of 0.05 μg/mL EXP could make breeding line L638 (Brassica juncea) and variety Qinyou No.4 (Brassica campestris) sterile, too. However, it was not suitable for producing hybrid because the period of male sterility of L638 was too short and the seedseting of Qinyou No.4 was poor (Table 3). The active ingredient of EXP belongs to sulfonylurea family that can inhibit acetolactate synthase (ALS, EC 4.1.3.18), the key enzyme that exist in the chloroplast of all green plants and catalyzes the common reaction to synthesize leucine, valine, and isoleucine. As a matter of fact, it have been found that other ALS-inhibiting chemicals could induce male sterility to a considerable level in oilseed rape and other Brassica family vegetables, too. A significance of this discovery may be the potential of a larger number of ALS-inhibitors to be used as the candidate of CHAs.

Genetic Variation at Gli-1 and Gli-2 loci in Wheat Cultivars from Shandong Province

GAO Ai-Ying;WU Chang-Ai;ZHU Shu-Sheng;WANG Xian-Ze

Acta Agron Sin. 2005, 31(11):  1460-1465. 

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Using acid polyacrylamide gel electrophoresis(A-PAGE), thirty-seven wheat cultivars and lines from Shandong Province were used to analyze the allelic variation and genetic diversity based on gliadin allelic composition at Gli-1 and Gli-2 loci in order to provide useful database for wheat breeding and quality improvement. The results demonstrated that 58 different gliadin alleles were identified in 37 wheat cultivars and lines, including Gli-A1（12）, Gli-B1（11）, Gli-D1（8）, Gli-A2（9）, Gli-B2（8）and Gli-D2（10）, of which 6 alleles were shown to be more frequent, i.e. Gli-A1a (48.6 %), Gli-B1l (35.1%), Gli-D1k (35.1%), Gli-A2b (35.1%), Gli-B2g (35.1%) and Gli-D2a (29.7%). It was also found that allele Gli-B1l, a marker for 1BL/1RS translocation, had a high frequency of occurrence. The genetic diversity of wheat cultivars and lines from Shandong Province is extensively with the mean Nei’s genetic variation index (H) of 0.7930, varying from 0.7297－0.8269. The highest genetic diversity was found at Gli-D2, while the lowest at Gli-A1. In addition, the composition of HMW (high-molecular-weight) gluten subunit was investigated in the wheat cultivars carrying good-quality gliadin alleles, such as Gli-B1b and Gli-A2b. The results showed that there were 5+10 gluten subunit associated with good bread-making quality in Yannong 15, Yanyou 361, Shannong 98-1 and Shannong 93-52 (Fig.3), indicating that these wheat cultivars were probably potential germplasms for improving wheat quality.

Effects of Temperature during Grain Filling on the Contents of Grain Protein Components and Free Amino Acid in Two Different Wheat Cultivars

ZHAO Hui;DAI Ting-Bo;JING Qi;JIANG Dong;CAO Wei-Xing

Acta Agron Sin. 2005, 31(11):  1466-1472. 

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High temperature during grain filling is a key climatic factor affecting wheat grain quality in Huanghuaihai and lower reaches of the Yangtze River in China. High temperature during grain filling decreases the duration of grain filling and increases protein content in wheat, but its physiological mechanism is unclear. The experiments were carried out in growth chamber to investigate the effects of high temperature and day/night temperature difference during grain filling on protein components formation and free amino acid content. Two wheat cultivars including Yangmai9 with low grain protein content and Xuzhou 26 with high grain protein content were treated under different temperature conditions during grain filling. Four day/night temperature regimes of 34℃/22℃, 32℃/24℃, 26℃/14℃ and 24℃/16℃ from 7 days after anthesis until maturity were used to obtain two daily average temperatures of 28℃ and 20℃, and two day/night temperature difference treatments of 12℃ and 8℃. The results showed that contents of crude protein, albumin, globulin and gliadin in grains were significantly increased, but gluten content was decreased by high temperature (Fig.1, 2, 3). When the day temperature was 34℃, protein content of Yangmai9 was decreased, but that of Xuzhou26 was increased. Consequently, the ratio of glutenin to gliadin was decreased by high temperature. Compared with optimal temperature treatments, free amino acid content was also increased in vegetative organs during early period of grain filling but significantly reduced in grains by high temperature during later period of grain filling (Fig.4, 5, 6), which indicated that increment of grain protein content under high temperature was associated with increasing free amino acid content in vegetative organs, and accelerating utilization of amino acids in grain. In addition, the optimal temperature difference of day and night favoring the formations of grain protein and protein components differed with wheat genotypes.

Comparative Research on Four Mapping Methods of QTLs

LI Jie-Qin;ZHANG Qi-Jun;YE Shao-Ping;ZHAO Bin;LIANG Yong-Shu;PENG Yong;WU Fa-Qiang;WANG Shi-Quan;LI Ping

Acta Agron Sin. 2005, 31(11):  1473-1477. 

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Four mapping methods, the interval mapping(IM) , the composite interval mapping(CIM), the mixed composite interval mapping(MCIM) and the multiple interval mapping(MIM), were employed to detect the quantitative trait loci（QTL） of rice plant height with an F₂ data from the intercross PA64S×Nipponbare. The results are as follows: (1) 7 significant QTLs were detected by IM，10 QTLs by CIM，3 QTLs by MCIM，1 QTL by MIM for the trait at the same significant level. So CIM had the highest detective capability among the four methods. (2) The loci detected by IM were also detected by the method of CIM, and aiming at the same QTL, their distance to the left marker was almost coincidence.（3）Only a same QTL could be detected by all the four methods, respectively, and the locus had the biggest contribution to plant height. (4) The differences for average of additive effects (absolute values) or dominant effects(practical values) of QTLs were insignificant among four methods and the dominant effects of the same QTLs had the same direction. (5) The epistatic effects could be estimated by MCIM and MIM in the four mapping methods. Only MCIM was employed to estimate the epistatic effects under the significant level at 0.005 because only one QTL was detected by MIM in the paper. (6) A suggestion for mapping QTLs is that multiple methods should be considered, and it is preferential to declare the QTLs confirm simultaneously by the four methods.

Heterosis of Late-maturing Japonica Hybrids (Oryza sativa L.) and Parent’s Combining Ability in South Jiangsu Region

JIN Wei-Dong; ZHANG Wang; HONG De-Lin

Acta Agron Sin. 2005, 31(11):  1478-1484. 

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Late-maturing japonica rice (Oryza sativa L.) is planted 10×10⁴ hectares annually in Suzhou region, Jiangsu Province. Average yield is about 9t/ha, which is the highest yield in Jiangsu province. At the beginning of 1990’s, the hybrid rice was popularized, and the planting area was enlarged gradually, increasing by 10%. However, as the continuous improvement of pure line variety, superiority of the hybrid has not been conspicuous. If this question cannot be solved well, the planting area of hybrid rice will be reduced. This study was conducted to evaluate parents of combinations used currently in the south of Jiangsu Province and the heterosis of late-mature japonica rice and combining ability of their parents. Seven CMS lines with BT cytoplasm and seven restorers were used as parents. CMS lines were newly bred in Wuzhong Institute of Agricultural Sciences. Restorers were introduced from other provinces or newly bred in Suzhou. With NCⅡ genetic design, 49 combinations (7×7) were made by paper bag isolation in Hainan. The plots of F1s and parents were arranged in the field in a randomized complete block design with 3 replications in Suzhou. Ten agronomic characters were investigated. Research results were as follows: ⑴ Both positive and negative heterosis existed in all the 10 characters. Among them, heterosis of spikelets per panicle was the highest，showing the average heterosis over 22.6% of the control and over 8.6% of high parents. The average value of the heterosis over high parent in yield per plant was 9.5%, the highest among ten characters, ranging from －38.0% to 43.9%. The competitive heterosis of yield per plant ranged from －54.8% to 10.3%(Table 3). ⑵For character of yield, 852-77A, Hou 36A and 9522A were elite CMS lines(table 5); 161-10, 3402, HP121 were excellent restorers(Table 6); 9522A/161-10, 9522A/C166、852-77A/3402 were superior combinations.

Screening Identification Indexes of Drought Resistance at Flowering Stage in Rice

WANG He-Zheng; MA Jun; LI Xu-Yi; LI Yan; ZHANG Rong-Ping; LIU Hui-Yuan; WANG Ren-Quan

Acta Agron Sin. 2005, 31(11):  1485-1489. 

Abstract ( 1734 )   PDF (378KB) ( 1309 )   Save

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Screening identification indexes of drought resistance has been one of the focuses in study on drought resistance. In this paper, ten indexes correlating with drought resistance including chlorophyll, proline content, MDA content, soluble sugar content, relative moisture content, leaf area and photosynthetic rate in flag leaf and the plant height were monitored under water stress at flowering stage for 10 paddy rice and upland rice cultivars. The identification indexes of drought resistance at flowering stage under water stress were screened by the main content analysis and the step regression analysis. The results showed that at flowering stage, proline content and relative moisture content in leaf, and leaf stomatal conductance and leaf areas significantly influenced the drought resistance and could be the indexes to identify the drought resistance in rice. The drought resistance of 10 rice cultivars was evaluated by stepwise regression equation and the results were basically consistent with the performance in paddy field, which indicated that it is feasible to predict the drought resistance in rice at flowering stage using the four indexes screened out in this study.

Easy Restoration of Fertility and Stability of Fertility Restoration for Male Sterile Line with Ae. kotschyi Cytoplasm in Wheat [Triticum aestivum (L.) Thell.]

ZHAN Ke-Hui;CUI Dang-Qun;LÜ De-Bin;XU Hai-Xia;CHENG Xi-Yong;FAN Lian;Dong Zhong-Dong

Acta Agron Sin. 2005, 31(11):  1490-1494. 

Abstract ( 1777 )   PDF (402KB) ( 860 )   Save

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Male sterility of Ae. kotschyi cytoplasm is considered better than that of T. tomopheevi, but there are some problems restricting its application in field production, such as inductive haploid and fertility restoration. K-type hybrids with two sterile lines (A) and certain restoring lines (R) were used to study the easy restoration of fertility (ERF) in two A-lines, stability of fertility restoration in different years, and effects of sowing time and rate on restoring degree. The results showed that there was obvious difference in ERF of A-lines and that the sterile line Yumai 3 was easier to be restored than S43 (Fig.1 and Fig.2). Genetic analysis of three-way cross combination indicated that ERF were controlled by two main genes and some other quantitative genes (Fig.3 and Table 1). The mechanism of ERF for A-lines and of restoring ability for R-lines were the same. The restoring degree of most K-type hybrids differed greatly in different years, but the hybrids with higher restoring degree had good fertility restoring stability(Fig.4 and Fig.5), so it was the most effective to identify restoring ability of R-lines under abnormal climates. Sowing time had a great effect and sowing norm had a small effect on restoring degree of K-type hybrid (Table 2). Abnormal high temperature during the period from ear emergence to anthesis were the main environmental reason affecting stability of restoring degree.

Genetic Analysis of Resistance to Sclerotinia Sclerotiorum in Brassica napus L.

HE Kun-Yan; FU Ting-Dong; TU Jin-Xing

Acta Agron Sin. 2005, 31(11):  1495-1499. 

Abstract ( 1896 )   PDF (410KB) ( 807 )   Save

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Resistance to sclerotinia sclerotiorum (Lid) de Bary in cross of DH821×DHBao604 (Brassica napus L.) was identified by mycelial toothpicks and petals inoculations, and the inheritance of resistance in this cross was analyzed by applying the major gene plus polygene model of quantitative traits to a joint analysis of multi-generations (P₁, P₂, F₁, BC₁, BC₂, F₂). The results showed that resistance measured 3 d after mycelial toothpicks inoculation was controlled by 2 pairs of major genes with additive effects plus polygene with additive-dominant effects. Heritability values of the major genes of BC₁, BC₂, and F₂ populations were from 12.49% to 28.48%, while these of polygene were from 21.08% to 27.87%. Resistance measured 5 d after inoculation was controlled by 2 pairs of major genes with additive-dominant-epistatic effects, among which dominant and associated epistatic effects were significant. Heritability values of the major genes of BC₁, BC₂, and F₂ populations were from 25.19% to 38.69%. Resistance to expansion of mycelia during 3－5 d after inoculation was controlled by 2 pairs of major genes with significant additive-dominant-epistatic effects plus polygene with low additive-dominant effects. Heritabilities of major genes and polygene in BC₁, BC₂, and F₂ populations were from 0.72% to 54.06% and from 7.34% to 46.79%, respectively. Resistance detected 15 d after infested petals inoculation was controlled by 2 pairs of major genes with additive-dominant-epistatic effects plus polygene with additive-dominant-epistatic effects. The additive and dominant effects of the major genes were from －3.605 to －3.5225, and the interaction effects from 3.5190 to 3.6089. Heritability of major genes and polygene in BC₁, BC₂ and F₂ populations were from 0.91% to 41.79% and from 19.32% to 73.69%, respectively.

Effects of 30% Diethyl-Amino-Ethyle-Hexanoate • Ethephon Aqueous Solution on Physiological Activities of Maize Roots

DONG Xue-Hui;DUAN Liu-Sheng;HE Zhong-Pei;TIAN Xiao-Li;LI Jian-Min;WANG Bao-Min;Li Zhao-Hu

Acta Agron Sin. 2005, 31(11):  1500-1505. 

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Roots is a vital part of the maize plant，however few of the research for practically regulating root function has been reported. In this study, the effects of a new mixture formulation of plant growth regulators registered in China, 30% diethyl-amino-ethyle-hexanoate • ethephon aqueous solution (30% DE AS), on maize (Zea may L. cultivar Nongda3138) were measured and evaluated in the cultivated condition of field and PVP-tubes. The physiological activities of roots were improved by foliage spray of 30%DE AS at the 6-leaves-expended stage of maize. The dry weight of roots, especially for the 8th layer of roots, was increased significantly by 30% DE AS. The roots activities of the 1st-4th and the 7th-8th layers were promoted at silking and filling stage, and the activities of invertase in the 1st－4th layer roots were higher than that in control. 15N tracing experiment showed that nitrogen accumulation in the whole plant and the 15N distribution in ears and roots was enhanced by 30% DEAS. The volume of root bleeding sap collected from the 1st internode of basal stem the content of total amino acids in bleeding sap were both increased. The contents of plant hormones (auxins, cytokinins, gibberellins and abscisic acid) in maize roots and root bleeding sap were also changed respectively by the foliage treatment of 30% DE AS. Cytokinins contents in root bleeding sap were increased remarkably, indicating the promoted transport of cytokinins from roots to shoots through xylem by 30% DE AS. The grain yield was increased by 11.7% and the yield components were also improved. 30% DE AS was proved to be a practical formulation of plant growth regulator for the improvements in grain productivity and physiological activities of roots mainly through the hormonal system.

Relationships between Starch Chemical Structure, Flour Viscosity Traits and Noodle Quality

KAN Shi-Hong;WANG Xian-Ze;YU Zhen-Wen

Acta Agron Sin. 2005, 31(11):  1506-1510. 

Abstract ( 1751 )   PDF (368KB) ( 1068 )   Save

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There are many reports about factors affecting noodle-making quality. However, few of them consider the characteristics of starch chemical structure (especially, the structure of amylopectin) and how they determine the physical properties, such as flour viscosity traits. So this study was carried out to investigate the relationships between starch chemical structure, flour viscosity traits and noodle quality. And it will facilitate the selection of noodle-specific wheat varieties.
Twenty wheat cultivars from Shandong province were grown in the farm of Shandong Agricultural University with same field managements in the year of 2001 and 2002. Seeds harvested in the two years were respectively stored for 3 months, and milled with a Junior-3100 experimental mill (Brabender company, Germany). Wheat starch was extracted, digested completely withα-amylase(EC 3.2.1.1, Sigma) and analyzed by High Performance Liquid Chromatograms (HLPC) with a Sugar-PAKTW carbohydrate analysis column (Waters). Flour viscosity traits were analyzed by 3-D RVA (3-D rapid viscosity apparatus, Newport Scientific company, Australia).
The results (Table 3) indicated that there were differences in digested product amount between cultivars. The amounts of oligosaccharides with a degree of polymerisation (DP)≥4 were significantly positively correlated with noodle quality scores. The correlation coefficients of DP≥4 oligosaccharides contents with noodle appearance and with elasticity were both higher. These indicate that the quality of noodles can be improved by DP≥4 oligosaccharides.
DP≥4 oligosaccharides has at least one branching point. The greater amounts of DP≥4 oligosaccharides, the more branches the starch has. So it is concluded that noodle made from the wheat with starch of more branch points tends to have good quality.
On the other hand, considering the fact that the starch with closer branches is digested more difficultly with α-amylase, a greater amount of digested DP≥4 oligosaccharides indicates that the given starch has not closer branches. So it can be deduced that wheat for high quality noodle probably contains the starch with loose branches.
At the same time, some flour viscosity traits were highly positively correlated with DP≥4 oligosaccharides contents, such as Peak Viscosity and Break down.
It is concluded, from the positive correlation between the amounts of DP≥4 oligosaccharides and noodle quality score, that wheat for high quality noodle contains the starch with more and looser branches.

RESEARCH NOTES

Screening Specific Tea Plant Germplasm Resources [Camellia sinensis (L.) O. Kuntze] with High EGCG Content

LIN Jin-Ke;ZHENG Jin-Gui;CHEN Rong-Bin;CHEN Chang-Song

Acta Agron Sin. 2005, 31(11):  1511-1517. 

Abstract ( 1475 )   PDF (368KB) ( 1003 )   Save

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Implement of Barley Stripe Mosaic Virus-Based Induced Gene Silencing in Wheat

LIU Xiao-Dong;ZHANG Zeng-Yan;YAO Wu-Lan;XIN Zhi-Yong

Acta Agron Sin. 2005, 31(11):  1518-1520. 

Abstract ( 1534 )   PDF (233KB) ( 895 )   Save

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Comparative Analysis of Dough Extensograph Characteristics Measured by Extensograph and Texture Analyzer

ZHANG Hua-Wen; TIAN Ji-Chun; DENG Zhi-Ying; LIU Yan-Ling; LI Yong-Qiang

Acta Agron Sin. 2005, 31(11):  1521-1523. 

Abstract ( 1909 )   PDF (184KB) ( 1032 )   Save

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Modeling Leaf Growth Dynamics in Winter Wheat

CHEN Guo-Qing;ZHU Yan;CAO Wei-Xing

Acta Agron Sin. 2005, 31(11):  1524-1527. 

Abstract ( 1394 )   PDF (260KB) ( 1222 )   Save

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Gene Transfer Effect of High Regeneration Ability from Seed-callus in Rice

ZHANG Lin; PU Xiao-Ying

Acta Agron Sin. 2005, 31(11):  1528-1530. 

Abstract ( 1437 )   PDF (251KB) ( 821 )   Save

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