Table of Content

12 May 2006, Volume 32 Issue 05

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ORIGINAL PAPERS

Quality Characters and Their Combining Abilities of Early Hybrid Rice in Yangtze River Area

DENG Hua-Feng; HE Qiang; MAO You-Chun; XU Qing-Guo; SHU Fu; ZHANG Wu-Han; YANG Fei and YUAN Long-Ping

Acta Agron Sin. 2006, 32(05):  633-639. 

Abstract ( 2011 )   PDF (600KB) ( 1195 )   Save

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The objective of this research was to establish the quality breeding theory of hybrid early rice in Yangtze River area through exploring the breeding means of the quality improvement of hybrid early rice. The hybrid early rice combinations between 6 sterile lines(A) and 5 restorer lines(R) of early indica rice grown in large area of Yangtze River basin were weed with NCⅡ genetic design, and 12 quality traits of them were measured and analyzed in this research. The result showed that the values of most grain quality traits were between their parents, chalky and milled rice rate were main limiting factors of the hybrid early rice quality in Yangtze River area. The statistical analysis revealed that there were a highly significant genetic difference among combinations and a highly significant influence of the quality-gene additive and non-additive effects on the hybrid early rice quality. The narrow-sense heritability of quality traits was ranged as follows: Length/Width > Length > Chalkiness >Width > Head Rice >Gelatinization temperature >Amylase Content >Chalky Grain >Chalky Area > Brown Rice > Gel Consistency >Milled Rice. Simple analysis of correlation showed that there existed significantly positive correlation between brown rice and milled rice; head rice and gelatinization point; grain length and grain length/grain width; grain width and chalky grain, chalky area, amylose content; chalky grain and milled rice width, chalky area, amylose content, chalky area and grain width, chalky grain, chalkiness, amylose content. There existed remarkably negative correlation between head rice and chalky grain; grain length/grain width, chalky grain, chalky area, chalkiness, gelatinization temperature, amylose content. The internal relationship, genetics and their improvement in 12 quality traits of hybrid early rice were discussed also.

Identification of QTLs for Heat Tolerance at the Booting Stage in Rice (Oryza sativa L.)

ZHAO Zhi-Gang; JIANG Ling; XIAO Ying-Hui; ZHANG Wen-Wei; ZHAI Hu-Qu and WAN Jian-Min

Acta Agron Sin. 2006, 32(05):  640-644. 

Abstract ( 2325 )   PDF (466KB) ( 1059 )   Save

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The utilization of heterosis between indica and japonica rice is an important approach to improve the productivity of rice. However, the reduced productivity due to the influence of abnormal temperature on spikelet sterility has been limiting the application of the indica-japonica cross of rice. The objective of this study was to identify the quantitative traits loci (QTLs) related to the spikelet fertility of the indica-japonica cross of rice under high growth temperature. The backcross population of USSR5/ Guangjie 9//USSR5 and related molecular map were constructed. The spikelet fertility under high temperature and heat susceptibility index (HSI) of spikelet fertility were used to evaluate the tolerance of rice to heat stress at booting stage, respectively. These QTLs related to heat tolerance at the booting stage were detected on chromosome 2, 4 and 5, respectively, which explained 6.4%–15.8% of the observed phenotypic variance. Two QTLs related to relative heat tolerance at the booting stage were detected, with LOD scoring 3.81 and 2.86 on chromosome 4 and 8, and explained 16.8% and 9.9% of the phenotypic variance, respectively. Further analysis of epistatic effected QTLs for relative heat tolerance showed that four pairs of loci exhibited interaction on 8 chromosomes, which indicated that the heat tolerance of spikelet fertility was not only controlled by main effect QTL but also influenced by gene interaction.

Improvement and Utilization of the Wheat Line YW243 with Multi-resistance Genes

ZENG Xiang-Yan;CHEN Xiao;ZHANG Zeng-Yan;#; XIN Zhi-Yong;LIN Zhi-Shan and ZHANG Yan

Acta Agron Sin. 2006, 32(05):  645-649. 

Abstract ( 1906 )   PDF (1096KB) ( 981 )   Save

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YW243 is the new lines of wheat carrying multi-resistance to powdery mildew, yellow dwarf virus and three rusts. Four lines with high yield and good disease resistance，including CB031, CB032, CB034, CB035 were developed By crosses between YW243 and some cultivars with elite agronomic characters. The resistance, resistance genes, grain quality, HWM-GSs and yield of these four lines were analyzed and compared with those of YW243 and the backcrossed parents. The results showed that CB031 possessed genes Pm2+6 controlling the resistance to powdery mildew and HMW-GSs of 1, 7+9, 2+12. CB032 possessed powdery mildew resistance genes Pm4+Pm2+6+Pm21, at lest a stripe rust resistance gene YrX on 2BL and HMW-GSs of 7+9, 2+12.The resistance genes Pm21 and HMW-GSs of 7+9, 5+10 were detected in CB034. CB035 possessed Pm2+6+Pm21，HMW-GSs of 7+8, 2+12. CB031 showed resistance to powdery mildew. CB032 showed immunity to powdery mildew and high resistance to 3 rusts. CB034 showed immunity to powdery mildew and stripe rust. The agronomic characters of these new lines, including kernel characters, ear characters, plant height，yield and quality, were improved compared with those of YW243. The study suggested that the wheat line YW243 is an available resistant parent in wheat breeding program against disease as its good characters could be inherited easily, while its undesirable characters could be improved easily.

Inheritance of Resistance to Race 1 and Race 4 of Cyst Nematode (Heterodera glycines Ichinohe) in Soybeans

LU Wei-Guo; GAI Jun-Yi; and LI Wei-Dong

Acta Agron Sin. 2006, 32(05):  650-655. 

Abstract ( 2041 )   PDF (495KB) ( 999 )   Save

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Soybean cyst nematode (Heterodera glycines Ichinohe) is one of the two most important nation-wide soybean diseases in China. Race 1 and 4 of the pathogen, especially the latter, are most popular in Huang-Huai Valleys and ZDD2315 and ZDD2226 have been identified as elite resistance sources. The present study was aimed to reveal the genetic mechanism of resistance to the two races by using the two resistant materials. Genetic analysis was performed under major gene + polygene mixed inheritance model in the four BC1F2 populations derived from the soybean crosses of Essex×ZDD2315, Peking×ZDD2315, PI88788×ZDD2226 and Peking×ZDD2226. The results showed that the resistance to Race 1 was controlled by two or three major genes, but no polygene effect detected. In Cross Essex×ZDD2315, three major genes contributed to the resistance to Race 1 with the heritability of 72.02%, while two dominant-epistasis major genes were detected with the heritability of 62.33% in Cross PI88788×ZDD2226. The two resistance sources, ZDD2315 and ZDD2226, might have the same resistant genes with Peking conferring resistance to Race 1 because the two crosses Peking×ZDD2315 and Peking×ZDD2226 did not segregate in reaction to Race 1. The resistance to Race 4 was mainly conditioned by three major genes plus polygene in the crosses of Essex×ZDD2315, Peking×ZDD2315 and PI88788×ZDD2226 with the major gene heritability of 67.76%, 72.46% and 53.25%, respectively and the polygene heritability of 24.48%, 21.31% and 35.77%, respectively. However only two major genes were identified in the cross of Peking×ZDD2226. All the F_1s and the detected additive effects had a similar response to susceptible parents, indicating the resistance to Race 1 and Race 4 mainly was controlled by recessive genes. Therefore, selection could be taken at early generations in breeding programs and pyramiding of genes resistant to both races should emphasize on resistance to Race 4 because most of the BC1F2 lines resistant to Race 4 also showed resistance to Race 1.

A Quantitative Analysis on Leaf Curvature Characteristics in Rice

SHI Chun-Lin; ZHU Yan and CAO Wei-Xing

Acta Agron Sin. 2006, 32(05):  656-660. 

Abstract ( 2047 )   PDF (404KB) ( 1049 )   Save

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With the development of computer graphics and crop simulation, virtual crop study, intuitionally expressing crop growth on computer, attracted many scientists to focus on this field. Some scientists have made great progress on the visualization of wheat, maize, soybean, rice and cotton, etc. Leaf shape is a very important characteristic in virtual crop growth modeling, and some empirical curves have been used to describe leaf morphology based on field experiments in the previous study. The fitting curves can help to understand organ morphogenesis, but the fitting parameters obtained from the given leaves and time cannot suit to changed growth process of leaves. So developing a mechanism model to simulate the leaf morphology is critical for virtual crop growth.
Organ morphogenesis of plant is decided to its forces. After force analysis on a rice leaf, the gravity fraction in leaf normal direction keeps equilibrium with elasticity, and then a dynamic leaf curvature equation was deduced with some assumption. The equation included the synthetic effect of leaf blade length, leaf blade width, initial leaf angle, specific leaf weight and deformation coefficient on leaf space shape. Then the equation was solved with parameterization. The sensitivity analysis showed that the equation could well reflect the integrated effects of leaf length, leaf width, specific leaf weight and leaf deformation coefficient, consistent with rice plant architecture in practice.
A field experiment was conducted at the Nanjing Agricultural University for validating the equation. Two cultivars (SU63 and WYG7) were nursed in dry-bed on May 20, and transplanted on June 20 with single seedling. Water and nutrients were supplied according to high yielding rice management. At jointing and booting stage of rice, the 3-dimension coordinates of several points in leaf midrib were measured with the 3D digitizer, and at the same time leaf blade length, width, initial leaf angle were obtained. Then simulation analyses were conducted on the equation with the experiment data. The results indicated that the leaf curvature equation could reasonably and reliably describe the change pattern of leaf shape characteristics of rice under different conditions.
The leaf curve equation could dynamically simulate the space shape of leaves with different initial leaf angles and special leaf weights by reduced parameters of rice leaf, especially in modeling day-to-day crop growth.

SCMV-resistant Transgenic Maize Mediated by Antisense cp Gene

BAI Yun-Feng; ZHAO Jin-Feng; ZHENG Jun; ZHANG Jin-Peng; WANG Mao-Yan; GOU Ming-Yue; DONG Zhi-Gang; YANG Hong-Chun and WANG Guo-Ying

Acta Agron Sin. 2006, 32(05):  661-665. 

Abstract ( 1901 )   PDF (563KB) ( 1024 )   Save

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Maize Dwarf Mosaic (MDM) disease is one of the most widely distributed and economically important virus diseases of maize in many countries. The disease is caused mainly by sugarcane mosaic virus (SCMV) in China. The resistance to the disease in maize containing virus-derived transgenes by the expression of functional coat protein gene(cp) from maize dwarf mosaic virus (MDMV) or SCMV has been reported and transgenic plants showed modest resistance to related viruses. But protein expression or mRNA transcription may pose problems with acceptance because of possible interactions with other viruses. And in these studies, selectable marker genes conferring antibiotic or herbicide resistance were used for the efficient transformation. The selectable marker genes have caused public concerns on the biosafety.
In an attempt to generate safe marker-free transgenic maize plants resistant to SCMV, we inserted SCMV cp gene in antisense orientation into 3’ end of a maize ubiquitin promoter and constructed a marker-free expression vector pACP that only harbors an antisense SCMV-cp gene. Maize immature embryos were co-transformed with the binary vector pACP and a vector harboring bar gene as the selective marker, using Agrobacterium inoculation procedure. Resistant calli were recovered by selection on medium containing Biolaphos. Among 35 regenerated plantlets from resistant calli, 14 plants were certified to contain antisense SCMV-cp gene by PCR amplification. T₁ lines derived from the 14 transgenic plants were challenged with SCMV inocula in field and the percentages of resistant plants in two lines were higher than 70%. Two SCMV-resistant transgenic plants in one T₁ line were found to be marker free by PCR assay. The results demonstrated that stable expression of antisense SCMV-cp gene in transgenic maize plants results in resistance to SCMV, which provides a new useful and effective alternative to combat SCMV because it does not require the expression of a functional viral gene product and avoid possible interactions with other viruses. In addition, generation of selectable marker-free transgenic plants avoids responds to public concerns on the biosafety of selectable markers and will support multiple transformation cycles for transgene pyramiding. The results further confirmed that co-transformation is a comparatively simple and available system for obtaining marker-free plants of a cross-pollinating propagated crop.

Programmed Cell Death during Abortion of Microspore in S-type Cytoplasmically Male-sterile Maize

MU Rui;ZHANG Zu-Xin;ZHANG Fang-Dong and ZHENG Yong-Lian

Acta Agron Sin. 2006, 32(05):  666-670. 

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The normal gametophyte development of S-type cytoplasmic male sterility（CMS-S）of maize is disrupted, and then microspores are aborted which fails to pollination. A set of near isogenic lines of CMS, S-Mo17^Rf3Rf3 and S-Mo17^rf3rf3, was used, and TdT-mediated dUTP nick-end labeling (TUNEL), in situ immunolocalization of cytochrome C and DNA ladder assay were employed to confirm that programmed cell death (PCD) process at cytology and DNA level. It is evident that the tapetal cells of fertile anthers kept intact until microspores, and then were disintegrated on later developmental stage. Whereas the tapetal cells of sertile anthers were earlier disintegrated when tetrad cells were disjoined. DNA ladder assay revealed that the cleavage of nuclear DNA into Oligonucleosome-sized fragments took place in pre-emergent anther,as well as in pollen cells from tasseled anther of S-Mo17^rf3rf3 . These results indicated that the abortion of sterile pollens was from not only prematuration of sterile anthers but also apoptosis of pollens . Results from TUNEL assay showed that nuclear DNA cleavage was happened from microspore stage to the stage of pollen aborting in sterile anther cell, but not in fertile anther cell. These results also supported the conclusion based on DNA electrophoresis. In addition, the release of cytochrome C from mitochondria to cytoplasm is a pivotal signal of launching PCD. The analysis of immunolocalization of cytochrome C showed that cytochrome C was not released before microspores stage in S-(Rf3) , but began to release when tetrad was disjoined in S-(rf3). During starch filling of pollen grain, DNA cleavage and the release of cytochrome C of tapetal cells were found in sterile and fertile anthers, however, these behaviors took place earlier in sterile anthr cell than in fertile anther cell.
Tapetal cell of anther plays important functions during tha development of microspores, such as providing nutrition, excreting b-1,3-glucanase to make microspores apart from tetrad. The release of pollen depends on the programmed death of anther celll too. The entire process of pollen development involves a series of fine modulation on molecular and cytological level. Each misregulation, such as abnormal excreting b-1,3-glucanase, prematuration of tapetal cells and abnormal trigger of PCD of anther cells, is likely to cause male sterility. The release of cytochrome C and the cleavage of DNA were observed at tetrad stage in sterile anthers but not in fertile anthers, implying that PCD which was launched earlier than preestablished programmer was a potential reason of pollen abortion in maize CMS-S.

Effect of Shading at Different Developmental Stages of Cotton Bolls on Cotton Fibre Quality

WANG Qing-Cai; SUN Xue-Zhen; SONG Xian-Liang; GUO Ying; LI Yu-Jing and WANG Zhen-Lin

Acta Agron Sin. 2006, 32(05):  671-675. 

Abstract ( 1960 )   PDF (463KB) ( 1034 )   Save

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Sunlight is one of the most important factors affecting cotton yield and fibre quality. There are more rain at flowering boll-forming stages in Yangtze valley, and unsuitable cotton population structure in Huanghe River valley limiting the increase of yield and the improve of fibre quality. The effect of sunlight on growth of cotton in seedling stage has been systemically researched, but limited research on fibre quality and the development in flowering boll-forming stages reported. The objective of this study was to evaluate the effect of shading on cotton fibre quality using the cultivars Zhongmiansuo 41 and Lumianyan 18 with three shading stages: boll age of 0–20 days (treatmentⅠ), boll age of 21–40 days (treatmentⅡ) and boll age from 41 days to bolling(treatmentⅢ).The results showed that the maximum fibre length of cotton was decreased and the elongation period was increased by shading. Fibre length was the maximum of CK at the boll age of 25 days without shading, while that of treatment I at the boll age of 35 days, and that of treatmentⅡ at the boll age of 30 days, but that of treatmentⅢ also at the boll age of 25 days. Fibre gauge tenacity and maturity were both decreased, but fibre fineness was increased under shading at different stages. Treatment Ⅱ was the most effective one affected fibre development and was significantly different from CK, while treatment Ⅰand treatment Ⅲ had less effect on fibre development. All the trends of the cotton fibre characters changed under shading were similar between two cultivars.

Mapping of Quantitative Trait Loci for Yield and Yield Components in Brassica napus L.

YI Bin; CHEN Wei; MA Chao-Zhi; FU Ting-Dong and TU Jin-Xing

Acta Agron Sin. 2006, 32(05):  676-682. 

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Although seed yield is one of the most important objectives in Brassica napus breeding program, it is poorly understood because of the multigenic and nongenetic influence. Recent advances in molecular marker techniques provide the possibilities to trace gene behavior at individual gene loci, which greatly helps to understand the complex genetics of quantitative traits of seed yield. The objective of our investigation was to acquire the information on the association between molecular markers and seed yield in Brassica napus and on the inheritance of these agronomic traits and to facilitate the selection in breeding programs. A double hapolid (DH) population derived from a cross between the rapeseed cultivars Zhongyou 821 and Bao 604 was used to identify quantitative trait loci (QTLs) for seed yield and yield components. Eighty-two double hapolid lines as well as two parent lines were evaluated in field environments in Wuhan, with two replications, for 7 agronomic traits, including plant height (PH), branch position (BP), length of main raceme (LMR), No. of primary branches (NPB), No. of pod per plant (NPP), 1000-seed weight (SW) and yield per plant (YPP). It was shown that all the seven agronomic traits had continuous phenotypic distributions and were suitable for QTL analysis (Table 2). A total of 261 molecular markers consisting of 2 RFLPs, 72 RAPDs, 91 SSRs and 86 SRAPs were employed to 82 DH lines and to construct the genetic linkage map, two hundred and fifty-one markers were assembled into 20 linkage groups (LG1–LG20), no linkage was found between the remaining 10 markers and any of the established linkage groups (Fig.1). The total map length was 1 746.5 cM with an average distance of 6.96 cM between adjacent markers. By employing complex interval mapping, a total of 17 putative QTLs were identified to be significant for the seven traits, of which 3 were for yield, 14 for yield components (Table 4). The phenotypic variation was explained by individual QTL ranged from 9.42%–17.58% for three QTLs of plant height, 8.13%–15.20% for four QTLs of branch position, 7.49%–23.36% for three QTLs of length of main raceme, 15.29%–19.58% for two QTLs of No. of primary branches, 17.42% for one QTL of No. of pod per plant, 7.64% for one QTL of 1000-seed weight and 8.11–9.78 for three QTLs of yield per plant. Some QTLs were mapped at the same or similar position in LG4, there were significant correlations between the corresponding traits. It suggested that the pleiotropism or tight linkage of QTLs for different traits might be the important genetic base for trait correlations. The molecular marker linked closely with main QTLs of yield and yield components in this paper could be used for MAS in rapeseed breeding program.

The Dynamics of Crop Yields under Different Fertilization Systems in Drab Fluvo-aquic Soil

LI Xiu-Ying; LI Yan-Ting; ZHAO Bing-Qiang; LI Xiao-Ping; WANG Li-Xia and ZHANG Zhen-Shan

Acta Agron Sin. 2006, 32(05):  683-689. 

Abstract ( 1739 )   PDF (609KB) ( 1037 )   Save

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The study on dynamics of crop yields, sustainable yield index (SYI) and agronomic efficiency of fertilizer under different fertilization systems including the treatment of N, NP, NK, PK, NPK, NPK+M (manure), NPK+S (crop straw) and CK (no fertilizer) were carried out based on 14 years’ long term fertilizer experiment in Drab Fluvo-aquic soil in Beijing. The results showed that N and P were two crucial limited nutrients of crop yield in Drab Fluvo-aquic Soil. In NPK treatment yield of wheat was increased by 459%, 386%, 280%, 205%, and corn by 154%, 108%, 87%, 78%, respectively, compared with these in CK, N, NK, PK treatments. The yield of NPK+M treatment was more 12% than that of NPK treatment. However, the yield of NPK+S was similar to that of the NPK treatment. The sustainable yield indexes of NPK, NPK+M and NPK+S treatments were greater than those of other treatments. The output of yields per unit fertilizer (i.e. agronomic efficiency of fertilizer, AEF) was varied considerably with different crops and combinations of fertilizers applied. The AEF of N for wheat and corn by single use of N fertilizer was reduced, while that of NPK treatment was 16 kg/kg N for wheat and 14 kg/kg N for corn and had an increase tendency during the experiment period. The AEF of P in wheat was greater than that in corn, further more, the AEF of P was 4.5–7.0 times higher than that at the beginning of the experiment 10 years ago. The AEF of K was negative in NK treatment, while increased rapidly in NPK treatment after 10-year crop cultivation; K was also one of critical limited nutrients for crop yield. The AEF of farmyard manure (FYM) in NPK +M treatment was 21 kg/t of wheat and 25 kg/t for corn, while the AEF of crop straw in NPK+S treatment was negative for wheat and 37 kg/t for corn. Soil O.M, total N, P and available N, P, K content were increased in NPK treatment. The accumulations of soil O.M and N, P, K nutrients were accelerated in NPK+M and NPK+S treatments. On the contrary, total N, total P were exhausted in the treatments without N, P fertilizer. Available P, K had the same variation trend in the treatments without P, K fertilizer.

Proteomic Analysis on Abscisic Acid Signal Transduction in Embryo Dormancy of Wheat (Triticum aestivum L.)

ZHANG Hai-Ping; CHANG Cheng and XIAO Shi-He

Acta Agron Sin. 2006, 32(05):  690-697. 

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The embryos of dormant and non-dormant cultivars of wheat (Triticum aestivum L.) were treated with ABA and protein expression was compared on two-dimensional electrophoresis gels. The results showed that 18 ABA-responsive proteins were expressed differentially. Among them, 16 protein spots were identified using MALDI-TOF-MS analysis and database searching. According to their characters, they may participate in different reactions, such as cold regulated protein, heat shock protein HSP26, aldehyde dehydrogenase are involved in stress reaction; auxin-responsive-like protein, ethylene receptor, calcium dependent protein kinase CP4, putative ethylene-responsive protein refer to signal cross pathway; and LEA B19.1, LEA 1, Em protein, bZIP transcription factor, zinc finger protein, myb family transcription factor, starch synthase, putative cellulase play certain roles in the seed development. One of two unknown protein was a gene product without significant homology to any protein but with full-length cDNA or EST homology, which covers almost the entire length of partial sequence of rice. Another was not identified using MALDI-TOF-MS or ESI-MS/MS analysis and suggested to be a new ABA-responsive protein in ABA signal transduction system. The protein patterns were studied in different development stages, ABA concentrations and imbibed courses in dormant and non-dormant states, so as to analyze the relationship between this protein level and dormancy trait. The results indicated that the two proteins were synthesized in middle or late-stage of seed development, which is consistent with the behavior of dormancy. The expression of the two proteins was easier in dormant embryos than in non-dormant embryos. At least 5-fold ABA concentration was required to produce similar results in non-dormant embryos. During imbibition, the expression of the two proteins in dormant embryos was prolonged and disappeared with breaking of dormancy. It is suggested that the expression level of the two proteins has relation to the maintenance of seed dormancy states. It is possible to clone the encoding gene and identify its function to provide candidate loci for sprouting resistance breeding in wheat.

Identification of Quantitative Trait Loci Controlling Resistance to Banded Leaf-Sheath Blight in Maize

ZHAO Mao-Jun; ZHANG Zhi-Ming; GAO Shi-Bin;; LI Wan-Chen; RONG Ting-Zhao; PAN Guang-Tang

Acta Agron Sin. 2006, 32(05):  698-702. 

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Banded leaf-sheath blight (BLSB) caused by Rhizoctonia solani Kühn in maize (Zea mays L.) is an important disease in China and Southeast Asia. Knowledge of the identification of quantitative trait loci (QTLs) for tolerance to this disease will facilitate the development of maize cultivars (hybrids) resistant to the disease. A genetic linkage map covered 1 666 cM on total ten chromosomes, with an average interval length of 11.4 cM was constructed using 146 simple sequence repeat (SSR) markers and the software MAPMAKER version 3.0b based on a maize population consisting of 229 F₂ individuals derived from a cross R15 (resistant) × 478 (susceptible). The disease index from the population of 229 F_2:4 lines were evaluated for BLSB resistance under artificial inoculation. With the method of composite interval mapping (CIM) described in QTL Cartographer V2.0 procedure, 9 QTLs controlling resistance to BLSB were identified on chromosomes 1, 2, 3, 4, 5, 6 and 10, accounting for 3.72% to 7.19% of the phenotypic variance. Among them, two QTLs were located in the region of 6.01 of chromosome where the resistance genes were usually located, which will be the important QTLs in the future study.

Effects of Pretreated with Glycinebetaine on the Fatty Acid Composition and Function of Wheat Thylakoid Membrane under Salt Stress

ZHAO Xin-Xi; MA Qian-Quan; LIANG Chao; FANG Yan and WANG Wei

Acta Agron Sin. 2006, 32(05):  703-708. 

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The thylakoid membrane inside the chloroplast is the position where the light reaction of photosynthesis takes place, therefore, its structure and function are nearly correlative with photosynthesis of the plant leaves. Glysinebetaine (GB) is a quaternary ammonium compound. Several authors have studied the function of GB as an osmoprotectant in the adaptation to water, salt and cold stress. The objectives of this study were to determine the effects of salt stress on the structure and function of thylakoid membrane and the protection of GB on it under salt stress condition. Two wheat (Triticum aestivum L.) lines HF9703 (drought-tolerant) and SN215953 (drought-sensitive) were used in these examinations. 100 mmol/L NaCl was used to induce salt stress condition. 1.5 mmol/L GB was used to study the function of GB on protecting thylakoid membrane from the damage of salt stress. The seedlings of two wheat lines were pretreated with Hoagland solution containing 1.5 mmol/L GB for 72 h, and then cultured with Hoagland solution containing 100 mmol/L NaCl for 48 h. The seedling leaves were used to study the effects of GB on the fatty acid composition and function of thylakoid membrane under salt stress. The results indicated that the level of linolenic acid (18∶3) in phosphatidylglycerol (PG) and phosphatidylcholin (PC) of SN215953 were decreased significantly by salt stress (Table 2), while it was only the level of linolenic acid (18∶3) in PC of HF9703 was decreased markedly by salt stress (Table 1). The decrease GB could be alleviated well by GB (Table 1, Table 2). Ca²⁺-ATPase activity of thylakoid membrane (Fig.3), Hill-reaction activity (Fig.4), chlorophyll content (Fig.2) and photosynthesis (Fig.5) were decreased markedly under salt stress, and that did more markedly in SN215953 than in HF9703. These effects of salt stress on thylakoid membrane were also ameliorated by GB. The salt tolerance of different wheat lines was accordant with their drought tolerance character, but there was some difference between them also. Discussions were made on the possible mechanism of the effects of salt stress on fatty acid composition and function of thylakoid membrane, as well as the presumable mechanism of the effects of GB on alleviating the change of fatty acid composition and improving the function of thylakoid membrane. However, the affirmable mechanism about it needs to be studied further.

Analysis for Protein Content in Rice by Near Infrared Reflectance Spectroscopy (NIRS) Technique

BI Jing-Cui; ZHANG Wen-Wei; XIAO Ying-Hui; WANG Hai-Lian; JIANG Ling; LIU Ling-Long; WAN Xiang-Yuan; ZHAI Hu-Qu and WAN Jian-Min

Acta Agron Sin. 2006, 32(05):  709-716. 

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Six predicted mathematic models for analysis of protein content in brown and milled rice were established, with the technique of near infrared reflectance spectroscopy (NIRS) and partial least square (PLS) algorithm. The protein content of brown rice and milled rice was determined by chemical methods. The different predicted models were established with the near infrared spectroscopy of paddy, whole grain and rice flour, which was to research the effect of sample forms on predicting veracity of NIR models. The determination coefficients (R_C²) of calibration of NIR models of brown rice protein content for paddy, whole grain and flour were 0.893, 0.971 and 0.987 respectively, the root mean square errors of calibration (RMSEC) was 0.507, 0.259 and 0.183. The RC2 of NIR models of milled rice protein content for paddy, whole grain and flour were 0.897, 0.984 and 0.986，the RMSEC was 0.497, 0.186 and 0.190 respectively. The veracity of models was estimated by the determination coefficients (R_CV²) and the root mean square errors (RMSECV) of cross-validation, the determination coefficients (R_V²) and the root mean square errors (RMSEV) of external validation. The R_CV² of NIR models of brown rice protein content were 0.865, 0.962 and 0.984 respectively，the RMSECV 0.557, 0.290 and 0.205. The R_CV² of NIR models of milled rice protein content were 0.845, 0.951 and 0.979，the RMSECV 0.594, 0.316 and 0.233. The R_V² of the NIR models for brown rice protein content were 0.683, 0.801 and 0.939，the RMSEV 0.962, 0.799 and 0.434. The R_V² of the NIR models for milled rice protein content were 0.673, 0.921 and 0.959，the RMSEV 0.976, 0.513 and 0.344. From the above results, we concluded that the veracity of flour NIR models is the best, that of whole grain better, while that of paddy poor. The NIR method can substitute the chemical method and be widely used in the breeding and quality analysis of rice.

Genetic Analysis of Main Nutrient Quality Characters in Normal Maize

LAN Hai; TAN Deng-Feng; GAO Shi-Bin; TANG Qi-Lin; CAO Mo-Ju; PAN Guang-Tang and RONG Ting-Zhao

Acta Agron Sin. 2006, 32(05):  716-722. 

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Thirteen inbred lines were used in incomplete diallel crosses (7×6) to analyze genetic effect of main nutrient quality characters in normal maize. The results indicated that main nutrient quality characters were controlled by embryo, endosperm, cytoplasmic and maternal genetic effects, which did not have much more difference among each other. The embryo genetic effects were represented as embryo additive effects of protein, starch and oil content. Endosperm effects of these main nutrient quality traits were all represented as endosperm dominance effects, and maternal additive effects was more important than maternal dominance effects. Predicted genetic effects showed that inbred lines 9636, 99s2041-1-1-1 and 478 were better than other parents, their genetic effects could play the role on the improvement of main nutrient quality characters in normal maize. Correlation analysis showed that there were different degree of genetic correlations between different nutrient quality characters; these quality characters could be improved by indirect selection and utilization of heterosis. The method applied in this study revealed much more genetic information than traditional NCⅡ analytic method. The results revealed by traditional NCⅡ analytic method could cooperate with Zhu’s method to instruct our breeding practice exactly. Because by the Zhu’s method, the total genetic effects is divided into some small parts, and which are difficult to use in practice. But it could help us to realize these complex characters such as nutrient characters more deeply than ever. The traditional NCⅡ analyze method could be easy operated in breeding practice. In this study, the experiment data were analyzed by using traditional NCⅡ analytic method. The results indicated that these four main nutrient quality characters all were controlled by female parent’s genetic effects, which were significantly different. These genetic effects, such as embryo, endosperm and maternal genetic effects have very complex relationships between each other. These three genetic effects all were controlled more or less by female parent and couldn’t be distinguish clearly. In fact, there were 2/3 endosperms as same as female parent in genetic components. And characters of kernel were controlled mostly by female parent in whole growing stage. So that, these female parent genetic variance of four main nutrient quality characters all were significantly different, because these genetic variance included some other genetic components. For oil content, the genetic variance of female parent and male parent were significantly different at 0.01 and 0.05 probability levels respectively. These correspond with high oil content maize breeding and utilization in practice, for example, the selection and synthesis of high oil content maize population and the xenia effect on normal maize of high oil content. In this study, P₁, P₂, F₁ and F₂ generation were need to predicate every genetic variance, covariance, effect and so on for four main nutrient quality characters. This method could be improved by increasing other generations, such as backcross generations, and by strictly experimental control and so on.

Effect of Nitrogen Application on Grain Yield and Processing Quality in Different Strong Gluten Wheats

ZHAO Guang-Cai; CHANG Xu-Hong; LIU Li-Hua; YANG Yu-Shuang; CHI Zhong-Zhi; YANG Li-Zhen and LI Zhen-Hua

Acta Agron Sin. 2006, 32(05):  723-727. 

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Seven bread wheat cultivars with high gluten content were used to study the effects of nitrogen fertilizer treatment on wheat quality and grain yield, and the difference within cultivars by the split plot design for two factors. The experiment was carried out on the Experimental Farm of the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences. The results showed that the grain yield was increased with the nitrogen application from 0 to 300 kg/ha and significantly different among treatments. However, the yield was increased only 3.1% when the nitrogen was applied from 225 kg/ha to 300 kg/ha (Table 1). So about 225 kg/ha of nitrogen application in practice is suggested. Contents of gliadin and glutenin (storage protein) were affected more than these of albumin and globulin (soluble protein), the contents of storage protein and gross protein were remarkably increased, and therefore processing quality was improved, by nitrogen treatments, the main characteristics of processing quality were improved with increasing the applied nitrogen within a certain range. Many important quality characteristics of baking bread including wet gluten, sedimentation, stable time, extension area, extensibility and so on were significantly improved for nitrogen treatments (Table 5). However, there were some differences among cultivars. Although some indices were different greatly, the bread volume and bread score were nearly the same (Table 6).

A Physiological Study on Pre-harvest Sprouting in Rice

TAO Long-Xing; WANG Xi; TAN Hui-Juan; CHEN Hai-Sheng; YANG Chang-Deng; ZHUANG Jie-Yun and ZHENG Kang-Le

Acta Agron Sin. 2006, 32(05):  728-733. 

Abstract ( 2065 )   PDF (434KB) ( 1106 )   Save

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“Pre-harvest sprouting” in rice is usually caused by high temperature and humility or continuous raining. It has frequently happened in F₁ in hybrid rice seed production. Those “Pre-harvest sprouting” or “Physiologically germinated” seeds are of lower quality, by which the hybrid rice seed production is badly affected, and the problem usually happens every three years. 20% or even 50% yield in the seed production losts by “Pre-harvest sprouting” in the Yangtze River and the South West areas. It is estimated that “Pre-harvest sprouting” causes an average decrease of seed activity by 10%.
A recombinant inbred line (RIL) population comprising 304 lines derived from a cross between indica rice (Oryza sativa L.) cultivars Zhong-156 and Gumei-2 was used to study the physiology of pre-harvest sprouting.
Based on the data of “Sprouting rate in panicle” and “Sprouting rate in grain”, two kinds of lines namely easy-sprouting lines and hardly-sprouting lines were selected to investigate their physiological differences when pre-harvest sprouting happened.
The experiment was conducted in a special field with higher temperature and higher humidity microclimate. The results indicated that female parent GM-2 was easier to produce pre-harvest sprouting than the male parent ZH-156, GA₁ content and amylase activity in GM-2 grains were higher than that in ZH-156. However, ABA content in GM-2 grains was lower than that in ZH-156. Higher temperature and higher humidity facilitated the GA₁ increment from milk ripe stage to yellow ripe stage, GM-2 and the easy-sprouting lines showed a even higher span of increase tendency than ZH-156 and the hardly-sprouting lines, which enhanced amylase activity and led to pre-harvest sprouting. This may be the physiological basis for pre-harvest sprouting induced by higher temperature and higher humidity, and these special characters must be inherited from their parents.

Expression of Three Members of ACC Synthase Gene Family in Sugarcane Induced by Hormones and Environmental Stress

WANG Ai-Qin; YANG Li-Tao; WANG Zi-Zhang; WEI Yu-Tuo; HE Long-Fei and LI Yang-Rui

Acta Agron Sin. 2006, 32(05):  734-737. 

Abstract ( 1980 )   PDF (416KB) ( 1016 )   Save

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1-aminocyclopropane-1-carboxylic acid synthase is one of the key rate-limiting enzymes for ethylene biosynthesis in higher plants. Based on the cloning of Sc-ACS1, Sc-ACS2 and Sc-ACS3 of ACS gene families, their expressions were tested in the roots and leaves of sugarcane with Sc-ACS1, Sc-ACS2 and Sc-ACS3 as the probes, respectively. The results of Northern blotting analysis showed that the expression of Sc-ACS1 was induced by ethephon in leaves, but not in roots; that of Sc-ACS2 in leaves and roots; and that of Sc-ACS3 in roots, while not in leaves. Under the environmental stresses（cold stress, dark-growing condition and LiCl stress）and hormone inducement (IAA), the mRNA of Sc-ACS1 showed a higher expression while that of Sc-ACS2 maintained low expression level in leaves.

Physiological and Ecological Effects of Water Collecting and Conservation Technique on Dry-land Millet

ZHANG De-Qi;LIAO Yun-Cheng;JIA Zhi-Kuan and JI Shu-Qin

Acta Agron Sin. 2006, 32(05):  738-742. 

Abstract ( 1713 )   PDF (412KB) ( 999 )   Save

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Film mulching technique (FM) and super water absorbent polymers(SW) were used in millet production. In this study, six water collecting and conservation treatments were carried out in millet production in southern Ningxia semi-arid areas，including solely furrow seeding with film and ridge technique, furrow seeding with film and ridge colligated SW, hole seeding on film mulching, hole seeding on film mulching with SW together, merely SW, and no film mulching and no SW as CK. During the experiment, the daily changes of photosynthetic rate during millet heading stage were measured, and the changes of moisture and millet yield were investigated. This study points out that the ‘midday depression’ was appeared in daily changes of photosynthetic rate under different treatments, but the integrative technique of FM and SW could abate it (Fig.1). Daily changes of transpiration rate were a single-peak curve (Fig.2), and the time of greatest stomatal conductance was at 8:00 am (Fig.3). Yield and water use efficiency (WUE) were increased by using FM and SW. The treatments of hole seeding on film and furrow seeding with film and ridge could increased the yield, which were 78.98% and 60.12% higher than that of non-mulched, respectively. The millet yield of SW seeding was enhanced 7.66% compared with no SW seeding. Furrow seeding with film and ridge after harvest was propitious to soil moisture, using the technique could increase water storage by 59.9 mm compared with CK in 2 m depth (Table 2).

Genetic Transformation of Sunflower (Helianthus Annuus L.) Mediated by Agrobacterium rhizogenes

TAO Jun; TAN Ru-Fang and LI Ling

Acta Agron Sin. 2006, 32(05):  743-748. 

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The transformation of Helianthus annuus L. mediated by Agrobacterium rhizogenes was reported. Almost all roots induced by different Agrobacterium rhizogenes bacterial strains which could survive in the selection medium (1/2 MS) containing 200 mg/L kanamycin were putative hairy roots. The effects of bacterial strains, bacterial concentrations, acetosyingone, silver nitrate and co-cultivation pH on sunflower transformation were investigated. For sunflower transformation, the optimal conditions were strain R1205, 1.0 bacterial concentration (OD₆₀₀), 15 minutes- infection, co-cultivation for 3 days as well as 30 μmol/L acetosyingone (without silver nitrate) and pH 6.5. Under this condition, the hairy root production frequency was 23.7% (cotyledon) or 81.6% (hypocotyl).

Pollen-mediated Transformation of Rape

DU Chun-Fang; LIU Hui-Min; LI Peng-Bo; SUN Yi and LI Run-Zhi

Acta Agron Sin. 2006, 32(05):  749-754. 

Abstract ( 2176 )   PDF (618KB) ( 1046 )   Save

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Plasmid DNA of pBI121 containing GUS gene and fresh pollen of rape Jinyou 7 were mixed in 7.5% sucrose solution and treated with ultrasonic. After that, pollens were collected, pollinated on stigmas of rape. With pollen tube growth through the style tissue and entering the ovaries, the target gene was integrated in rape genome. Transformed plants were confirmed by field character identification(Fig.2), histochemical assay of GUS expression(Fig.3), DNA dot blot hybridization(Fig.4), PCR amplification(Fig.5) and PCR-Southern blot hybridization(Fig.6).
In the study, some regeneration conditions, such as the concentration of sucrose solution, the intensity of ultrasonic and the effective of auxiliary agent for transformation system were discussed. The highly efficient transformation system on rape was established with 7.5% of sucrose solution (Fig.7) or 5% of manna sugar solution (Fig.8), 300 W of ultrasonic (Fig.9).
Compared with other approaches, the pollen-mediated transformation approach can avoid the tedious tissue culture procedures like in Agrobacterium infection and particle bombardment, etc. This approach is simple, easy to operate, and can be widely used in breeding practice.

Construction of Tomato Chloroplast Multicistron Site Integration Expression Vector and Its Transgenic Tobacco

LU Yun-Hua; MA Li-Xin; and JIANG Si-Jing

Acta Agron Sin. 2006, 32(05):  755-761. 

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According to the published DNA sequence (GenBank Z00044.1) of tobacco chloroplast high-frequency homologous recombination fragment, primers were designed to amplify a 3.663 kb DNA fragment named ctDNA from chloroplast genome of tomato by PCR. The fragment was not only 96.7% homology compared with the tobacco fragment reported in GenBank, but also 95.8% homology compared with the tobacco fragment used in this paper. The tomato chloroplast multicistron expression vector pLM2（Fig.1） (-psbD-Prrn-RBS-man-RBS-gfp-RBS-aadA -psbA3’-trnG-) was constructed with ctDNA, Prrn, man, gfp, aadA and psbA3’. And the tobacco leaves were bombarded with golden particles coated with the vector pLM2. Three transgenic tobacco shoots were obtained on the screening medium. The function of aadA gene was identified by screening medium（Fig.3）, and the function of gfp gene was confirmed by laser scanner（Fig.4）. The expression of man gene was identified by Western blot（Fig.5）. The genes man, gfp and aadA being in the chloroplast of tobacco were confirmed by PCR（Fig.6）. And the tobacco chloroplast multicistron expression cassette integrating in tobacco chloroplast genome DNA was confirmed by RFLP（Fig.7）. The results were showed that the three genes( man, gfp, aadA ) which were in the tomato chloroplast multicistron expression vector pLM2 were expressed in tobacco chloroplasts.

Detection Putative Protein Partners of the Precursor of Small Subunit of Rubisco (preSSU) by a Yeast Two-hybrid System

XIA Lan-qin; Soll Jürgen and HE Zhong-Hu

Acta Agron Sin. 2006, 32(05):  762-765. 

Abstract ( 1873 )   PDF (430KB) ( 861 )   Save

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Correct, efficient targeting and translocation of the precursor proteins synthesized in the nucleus into chloroplast is vital for the chloroplast function. The yeast two-hybrid system was employed to screen a pea cDNA expression library, and investigate the factors involved in interacting with preSSU (precursor of small subunit of Rubisco). The protein product of six different kinds of genes were putative partners of preSSU: the candidate histidine protein kinase gene, the translocation protein complex, transcriptional and translocation related genes and proteins, plant defensin proteins, the gibberrellin regulation factor and EREB transcriptional factor, and photosynthesis related genes. The preSSU probably participates in different processes involved in plant responses to stress and pathogen infection, and plays an important role in plant growth, maturity and senescence. However, further research is needed to determine how these factors interact with preSSU and regulate its import.

Effect of Cake Fertilizer on the Pigments Degradation and Related Enzyme Activities in Flue-cured Tobacco

WEI Feng-Jie; FAN Yi-Kuan; LIU Guo-Shun; WANG Fang; LI Ya-Juan and GUO Qiao-Yan

Acta Agron Sin. 2006, 32(05):  766-771. 

Abstract ( 1877 )   PDF (480KB) ( 970 )   Save

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Plastid pigments are important natural products in flue-cured tobacco and there are about two types such as chlorophyll and carotenoid. In green tobacco two major chlorophylls are present: chlorophyll a and chlorophyll b(Fig.1). Four major carotenoids are present: lutein, beta-carotene, violaxanthin and neoxanthin(Fig.5). It is known that carotenoid degradation products such as beta-ionone, damascenone, beta-damascone, 2,2,6-trimethylcyclohex-2,4-dione and the megastigmatrienones are important to the aroma of flue-cured tobacco. Cake fertilizer can increase the qualities of flue-cured tobacco leaves, as we know. Our knowledge of pigments degradation pathways is limited to studies of enzymatic degradation in tomatoes, the degradation of beta-carotene by a tea flavanols. Study on pigments degradation and related enzyme activities and the effect of cake fertilizer can improve the quality-formed theories of flue-cured tobacco.
Pot experiment was conduction to study the effect of cake fertilizer on the pigments metabolism and relating enzyme activity of growing flue-cured tobacco leaf. Two types fertilizer were performed: mineral fertilizer and 50% mineral fertilizer matched 50% cake fertilizer. Results obtained are as follows: The content of Chlorophyll, Chlorophyllase, Carotenoids during the growth of flue-cured tobacco leaf under the cake fertilizer. Under the mineral fertilizer, the proportion of chlorophyll a/b was holding invariableness, but the proportion of chlorophyll a/b was lower during the later senescence under the cake fertilizer. During the former and metaphase the content of neoxanthin under the cake fertilizer was more, but it was changed during the later phase. The content of lutein and β-carotene in condition of cake fertilizer were remarked more than theirs in the mineral fertilizer condition. Two conditions had sameness effect on vioxanthin. During the former phase of flue-cured tobacco leaf the activity of LOX(mineral) were higher, but after 30 days the activity of LOX(Cake) were remarkable higher than minerals. Proportion of the carotenoids and the relation of the pigment and relating enzyme had changed under the cake fertilizer.


Effects of Different Types of Nitrogen Fertilizer on Nitrogen Accumulation, Translocation and Nitrogen Fertilizer Utilization in Summer Maize

YI Zhen-Xie; WANG Pu; SHEN Li-Xia; ZHANG Hong-Fang; LIU Ming and DAI Ming-Hong

Acta Agron Sin. 2006, 32(05):  772-778. 

Abstract ( 2053 )   PDF (611KB) ( 1196 )   Save

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In recent years, nitrogen over fertilization has become an unassailable fact in summer maize-winter wheat cropping system in north China plain, especially in summer maize growing season, resulting in N use efficiency (NUE) rapidly decrease and causing a series of ecological and environmental problems, such as underground water pollution, acid rain, global warming and stratospheric ozone depletion, and so on. The objective of this experiment was to study the effects of three application rates (0, 90 and 180 kg N/ha) of three types of nitrogen fertilizer (common urea, coated urea and compound fertilizer) on N absorption, accumulation, translocation and nitrogen fertilizer (NF) utilization of summer maize cultivars, Zhengdan 958 and ND 108 under condition of lower NF application rate, and to provide some beneficial references for ameliorating the fertilization techniques and increasing NUE of summer maize in this area. The main results showed that N accumulation amount was increased but nitrogen physiological efficiency, nitrogen fertilizer efficiency and NUE descended with the increment of N application rate from 0 to 180 kg N/hm2. Under condition of the same N application rate, NUEs of coated urea and compound fertilizer treatments were bigger than that of common urea treatments, especially in the treatments of 90 kg N/ha for Zhengdan 958 and 180 kg N/ha for ND 108 (Table 2, 5 and 6). Difference existed in N staggered accumulation trends between two cultivars under zero N application, and their alternation under N application showed genotypic difference likewise (Table 2). In N application treatments, N accumulation amount was increased before silking stage, but descended in middle and late filling stage, and this trend was more evident for Zhengdan 958. N absorption of summer maize, especially of Zhengdan 958 in the middle and late filling stage could be restrained if N accumulation amount was too much in the stage of sowing to 21 d after silking. There was a genotypic difference in nitrogen harvest index (NHI), nearly 6% more in Zhengdan 958 than in ND 108. With NF application, NHI of Zhengdan 958 was descended evidently, but that of ND 108 changed unconspicuously. Compared to NHI under common urea application, NHI under coated urea and compound fertilizer application was lower and the difference was significant at 0.05 probability level when N application rate was 90 kg N/ha for Zhengdan 958 and 180 kg N/ha for ND 108 (Table 2). Translocation amount of leaf N and stem-sheath N and their contribution rates to grain N were increased with the increment of N application. Leaf N was translocated to grain mainly from 21 d after silking to maturing stage, but stem–sheath N did mainly from silking to 21 d after silking stage (Table 4). Fertilizer-N played the role mainly before silking, especially from 12–leaf to silking stage, and the difference of N accumulation amount between N application treatments and zero N treatment reached to the maximum around silking stage.

Dynamic Changes of GMP Content and Net Genetic Variation in Wheat RIL Population

LI Wei-Hua; Xu Qi; YOU Ming-Shan; Xu Jie; CHANG Cheng; LIU Wei; LIU Li; LI Bao-Yun; and LIU Guang-Tian

Acta Agron Sin. 2006, 32(05):  779-784. 

Abstract ( 1911 )   PDF (479KB) ( 892 )   Save

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The experiment was conducted using 175 recombinant inbred lines （RILs） derived from a cross between common wheat Jing 771 and Pm97034. The results indicated that the GMP content in most RILs was accumulated at low level in early stage of grain filling, then ascended gradually, but descended at about 22 days after anthesis, then ascended continually up to maturity, which was the same as that in their parents. The effects of different subunit combinations on the dynamic changes of GMP content were different. The GMP content in the RILs with（1,17+18,5+10）, (N,17+18,5+10),（1,14+15,5+10）,（N,14+15,5+10） subunit combinations were quickly accumulated from 27 days to 32 days after anthesis, and up to the highest value at maturity. The four subunits combinations especially the 5+10 subunits were favorable to GMP accumulation. The results of conditional genetic variance components showed that the GMP quantitative genes were expressed from filling to mature, and most active at 17 days after anthesis, while inactive at about 22 days after flowering. The dynamic changes of the GMP net genetic variation were similar to that of GMP content accumulation.

RESEARCH NOTES

Morphological and Cytological Characterizations of Trisomics, Double Trisomics and Double Tetrasomics in Brassica napus

HUA Yu-Wei; WANYAN Rui-Hong; XU Jing and LI Zai-Yun

Acta Agron Sin. 2006, 32(05):  785-786. 

Abstract ( 2148 )   PDF (175KB) ( 957 )   Save

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One plant (2n=42) was identified among the microspore—derived plants from one Brassica napus cv. Oro × Orychophragmus violaceus hybrid (2n=19~37), in which no O. violaceus chromosomes were detected, so the plant has only B. napus chromosomes. After Oro was pollinated with the pollen grains from the plant, progeny plants (2n=39, 40) were produced. Meiotic pairing configurations of the plants (2n=39, 40, 42) were mainly 19Ⅱ+1Ⅰ, 19Ⅱ+2Ⅰ and 21Ⅱ, and segregations at anaphase Ⅰ were 20∶19, 21∶19 and 21∶21, respectively. Thus the plants (2n=39, 40, 42) were trisomics, double trisomics and double tetrasomics of Brassica napus, respectively. Finally implications of these new aneuploids in rapeseed genetic researches were discussed.

Clone of Partial Sequence of Caffeoyl-CoA 3-O-Methyltransferase Gene in Ramie

CHEN Jian-Rong; ZHANG Xue-Wen and GUO Qing-Quan

Acta Agron Sin. 2006, 32(05):  787-790. 

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The objective of this study was to examine the sequence of ramie CCoAOMT and investigate ramie lignin biosynthesis pathway. High quality RNA(Fig.1) and DNA were extracted from ramie [Boehmeria nivea（L.）Gaud] and used as a template for cloning the caffeoyl-CoA 3-O-methyltransferase gene cDNA by RT-PCR with degenerate primers under gradient temperature. Colonies with target foreign DNA inserts was identified by PCR (Fig.2). Recombinant pMD18-T plasmid was identified by restriction digestion (Fig.3) and PCR (Fig.4), also sequence analysis. Ramie caffeoyl-CoA 3-O-methyltransferase gene cDNA partial sequence with GenBank accession number AY651026 is 486 bp long, coding 162 amino acids. The result of the domain analysis showed the ramie CCoAOMT to be a member of the O-methyltransferases family. CCoAOMT gene was first discovered in Boehmeria nivea（L.）Gaud and was first documented and recorded as a part of the Urticaceae family.
The new partial genomic sequences of the cloned ramie CCoAOMT gene resulted in the new GenBank accession numbers: AY818191 (Xiangzhu 3, 922 bp), AY822619 (Yuanma, 915 bp), AY822620 (Luzhuqing, 914 bp) and AY822622 (Qingma, 914 bp). The results of bioinformatic analysis showed that the four sequences were different in length and had three introns each. In each of the four sequences the first introns are different in length, the second in some base mutations, and the third in both length and base mutation.
Future research is necessary in order to study and see if these differences cause the differences in the gene expression or not. There were only 5 different bases in the extron of the 4 sequences. Corresponding to the cDNA sequence, in genomic sequences, in the 24^th base, the base mutation did not cause an amino acid change, Pro was coden; in the 185 ^th base, the base mutation caused the changes of amino acid, resulting in Thr and Asn coden with two distinct quality; in the 188 ^th base, the base mutation caused the changes of amino acid resulting in Ala and Gly coden, which was similar in quality; in the 337 ^th base, the base mutation caused the changs of amino acid resulting in Ile and Leu coden which was similar in molecular consistency but different in structure; lastly, in the 423 ^th base, the base mutation did not cause the changes of amino acid coden and remained Leu coden. Future research is also necesary in order to determine if these amino acid changes caused enzyme activity changes or not.