Table of Content

12 March 2007, Volume 33 Issue 03

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ORIGINAL PAPERS

^{Cloning and Expression Analysis of a New Glutelin Gene cDNA in Rice}

NIU Hong-Bin;QIN Huai-De ;WA NG Yi-Hua ;ZHAI Hu-Qu;WAN Jian-Min ;

Acta Agron Sin. 2007, 33(03):  349-355. 

Abstract ( 2091 )   PDF (2246KB) ( 1366 )   Save

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Rice seeds with rich reserve of starch and protein are a major food source in many countries. Unlike the seeds of other plants, which typically accumulate one major type of storage protein, rice seeds contain two major proteins, prolamines and globulin-like glutelins. Glutelin, which accounts for 70%–80% of the total proteins of rice seeds, is coded by a multi-gene family, and to date at least nine different cDNAs have been isolated. After transcription in the cell nucleus, rice glutelin mRNA is targeted to a specific subdomain of the cortical endoplasmic reticulum (ER) where it is translated to synthesize a larger precursor with a signal sequence which is cotranslationally processed during translocation to the ER lumen whereupon correct folding and disulfide bond formation occur. The glutelin precursor is then transported to vacuolar protein bodies (PB-Ⅱ) presumably by way of the Golgi complex. At PB-Ⅱ, glutelin is proteolytically processed into acidic (a) and basic (h) polypeptides. Accoding to the primary sequence comparisons, glutelin can be classified into A and B types. Rice seed proteins are deficient in the essential amino acid, lysine. Therefore, nutritional improvement in the amino acid composition of rice proteins is needed. B type glutelin is superior to A type in terms of nutritional value since B type has more of the first limiting amino acid, lysine. For this reason, B type glutelin should be a noteworthy genetic resource to improve rice protein quality.
Here we reported the cloning and characterization of cDNA for a new rice glutelin gene from a local cultivar (Oryza sativa L). After screening the rice endosperm cDNA library by 32P-labeled GluB-2 cDNA probes (1 389 bp), we cloned a new glutelin gene cDNA, named GluB-7 (GenBank accession number AY987390). DNA sequence analysis showed that the size of the cloned cDNA was 1 588 bp, and carried entire coding sequences, which encode a 495 amino acid protein, corresponding to the size of the glutelin protein family. Signal peptide prediction with software found that GluB-7 included a 24-residue signal peptide with the cleavage site between arginine and glutamine and a 471-residue mature protein. Homology analysis showed that the deduced amino acid sequence of GluB-7 shared 57.8%–97.8% identity with others of rice glutelin gene family. Southern blot analysis of the genomic DNA showed the presence of multiple copies in the rice genome. Northern blot analysis using GluB-7 cDNA partial sequence as a probe showed that the GluB-7 was expressed specifically in rice endosperm, and the largest accumulation of mRNA occurred in 12 DAA, while no corresponding band was found in roots, stems, and leaves. The cloning of GluB-7 cDNA provides the basis for future studies on glutelin gene expression, the identification of the molecular mechanism of rice seed storatge protein biosynthesis, and especially the improvement of protein quality in rice breeding.

Introduction of Phosphoenolpyruvate Carboxylase Gene from Echinochloa crusgalli into Wheat Mediated by Agrobacterium tumefaciens

ZHANG Bin ;DING Zai-Song ;ZHANG Gui-Fang ;SHI Yun-Lu ;WANG Jin-Ming ; FANG Li-Feng ;GUO Zhi-Jiang ;ZHAO Ming ;

Acta Agron Sin. 2007, 33(03):  356-362. 

Abstract ( 2062 )   PDF (1441KB) ( 1068 )   Save

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It has long been postulated that the transfer of C₄ traits to C₃ plants could improve the photosynthetic performance of C₃ plant species. Several attempts have been made to transfer C₄ photosynthetic traits, with the emphasis on PEPC, to rice plants using genetic engineering techniques. The photosynthetic rates of transgenic rice plants over-expressed PEPC were comparable to those of the untransformed control plants. Recently, maize PEPC gene was first introduced into wheat and the same results were found. These results enlightened us to introduce PEPC into wheat to increase photosynthesis and yield. In this study, wheat calli derived from immature embryos of three cultivars of spring wheat (Yangmai 158, Bobwhite, and Yangmai 12) were cultured for 10 to 12 days and transformed with three strains of Agrobacterium tumefaciens (LBA4404, EHA105, and C58c1) harboring expression vector pUbi-Ecppc which carrying Gus, Hpt, Ecppc genes. Both Gus gene and Hpt gene are promoted by CaMV35S promoter, and Ecppc gene were promoted by maize Ubiquitin promoter. Factors that influence Agrobacterium-mediated wheat transformation, including concentration of antibiotics during selection, concentration of bacterium suspension, temperature and time of co-culture, receptor genotype and bacterium strains, were investigated. With the established wheat genetic transformation system, Ecppc from Echinochloa crusgalli was transferred into wheat firstly and hygomycin resistant plantlets were obtained, with a transformation efficiency of up to 3.03% in Yangmai 158. Fourteen PCR positive transgenic wheat plants from 816 co-cultured calli were obtained and the integration and transcription of transgene was confirmed by Southern blot and RT-PCR analysis. Physiological studies showed that the transformants displayed higher photosynthesis and PEPC activity.

Genetic Correlation Analysis between Yield and Its Components and Cooking Quality by using a Rice DH Population

YAN Chang-Jie;CHEN Feng;YAN Song;ZHANG Zheng-Qiu;TANG Shu-Zhu;LI Xin;GU Ming-Hong;

Acta Agron Sin. 2007, 33(03):  363-369. 

Abstract ( 2039 )   PDF (568KB) ( 1127 )   Save

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Many high-yield varieties usually exhibit inferior grain quality in rice. The understanding of the relationship between rice yield and its components, cooking and eating qualities is beneficial for successfully breeding the high-yield variety with good quality. A DH population, consisting of 130 lines, derived from the cross between japonica cultivar Nongken 57 and Wuyunjing 8, was employed to explore the genetic correlation between yield traits and cooking quality. In the DH population, the productive panicles per plant, grains per panicle, grain density, and yield per panicle significantly correlated with PKV, HPV, BDV, CPV, SBV, and CSV positively or negatively, while no significant correlations between other yield traits and cooking quality indices were detected, preliminarily indicating the certain correlation between yield and grain quality. Furthermore, to fully understand these correlation relationships, 60 SSR markers distributed on the entire rice genome, being polymorphic between two parents, were used to detect the genotypes of each line; composite interval mapping and marker-based analysis of variance were employed to analyze the genetic basis for yield traits and cooking quality indices. The results showed that there were a QTL in the interval of RM234–RM505 on chromosome 7 conferring yield per plant, PKV, HPV, and CPV simultaneously，and another QTL at RM454–RM162 on chromosome 6, with effects on grain density, BDV, and SBV. But it also should be pointed out that no QTLs were found contributing to yield per plant, BDV, and SBV, simultaneously, the latter two indices were related to cooking quality. Taken together, it is possible that high yield variety with good quality can be achieved through optimizing the structure of yield components, together with selection of favorable alleles on the gene loci conferring rice grain quality.

Subspecies Characteristics in Filial Generation of Cross between Indica and Japonica under Different Environments

XU Hai;LIU Hong-Guang ;YANG Li ;ZHU Chun-Jie ;WANG Jia-Yu ;YANG Qian-Hua;XU Zheng-Jin ;;ZHENG Jia-Kui

Acta Agron Sin. 2007, 33(03):  370-377. 

Abstract ( 2070 )   PDF (629KB) ( 921 )   Save

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The RILs population derived from the cross between “Zhongyouzhao 8” (Hsien or Indica) and “Fengjin” (Keng or Japonica) was grown in Liaoning and Sichuan province to compare the subspecies characteristics under different environments .The results showed that the distribution of Cheng’s index was japonicalinous. The population was more japonicalinous in Sichuan than in Liaoning as a whole. Further analysis indicated that indica and indica-cline in Sichuan were more indicalinous than those in Liaoning, japonica and japonica-cline in Sichuan were more japonicalinous than those in Liaoning. The effects of environment on six characteristics of Cheng’s index were different because of different characters, as well as on the correlations between the six characters, the Cheng’s index and the vascular bundle traits. For example, the length of first and second rachises and leaf pubescence were more japonicalinous in Sichuan than in Liaoning, while the length/width ratio of spikelets and glume color at heading time were more indicalinious in Sichuan than in Liaoning. The vascular bundle characteristics of RILs in different environments changed remarkably. The number of large vascular bundles in panicle neck was less in Sichuan than in Liaoning, and the number of small vascular bundles in panicle neck and second top stem was greater in Sichuan than in Liaoning. The ratio of large to small vascular bundles in panicle neck was decreased and the ratio of large vascular bundles between the second top stem and panicle neck was increased in Sichuan. Though total trend was the vascular bundle ratio of large to small in indica was greater than that in japonica and the ratio of large vascular bundles in indica was less than that in japonica, it is not appropriate that the vascular bundle ratio of large to small and the ratio of large vascular bundles are regarded as the parameters for subspecies classification in rice. The vascular bundles characteristics from typical indica or japonica were recombined in the population derived from indica and japonica crossing.

QTL Mapping of Phosphorus Deficiency Tolerance in Soybean (Glycine max L.) during Seedling Stage

CUI Shi-You ; GENG Lei-Yue;MENG Qing-Chang ;YU De-Yue ;

Acta Agron Sin. 2007, 33(03):  378-383. 

Abstract ( 2100 )   PDF (493KB) ( 1079 )   Save

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Phosphorus (P) deficiency is a major abiotic stress that limits productivity of crops such as soybean throughout the world. In the present investigation, 151 recombinant inbred line (RIL) families derived from a cross between Bogao and Nannong 94-156 (low phosphorus tolerant germplasm) and their genetic maps were used to detect quantitative trait locus (QTL) associated with P deficiency tolerance by pot culture of soybean seedlings with two treatments of minus-P and plus-P. After six weeks of seeding, the relative total dry weight (RTDW), relative phosphorus uptake per plant (RPU), relative phosphorus use efficiency (RPUE), and relative root to shoot ratio (RR/S) were measured as indices for tolerance to phosphorus deficiency. The primary results showed that total dry weight under P-minus condition was determined by phosphorus uptake per plant, and no correlation between phosphorus use efficiency and total dry weight. Phosphorus uptake per plant was significantly and positively correlated with root dry weight and root efficiency (P uptake per unit weight of root), and 76.2% of variation of phosphorus uptake per plant came from root efficiency. Root/shoot ratio under P-minus condition was increased significantly due to no significant change of shoot dry weight and significant increase of root dry weight. Seven QTLs associated with phosphorus deficiency tolerance were detected and mapped on the linkage groups of D1b+W, F, G, N, and O. Each QTL explained 4.8%–17.0% of phenotypic variation, positive alleles of five QTLs among them were from female parent ‘Bogao’, and those of the other QTLs from male parent ‘Nannong 94-156’. Three of seven QTLs were mapped on linkage group G, among them one major QTL for RTDW explained more than 10% of the phenotypic variation was detected between sat_203 and sat_185 on LG-G by using CIM and MIM methods.

Gene Effect Analysis and Evaluation of Application Potential of Rice Dominant Earliness Gene Ef-cd

DONG Chun-Lin ;SUN Ye-Ying ;WANG Ping-Rong ;HUANG Xiao-Qun ; DENG Xiao-Jian ;

Acta Agron Sin. 2007, 33(03):  384-388. 

Abstract ( 2032 )   PDF (390KB) ( 1076 )   Save

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Ef-cd gene is a dominant earliness gene located on the short arm of rice chromosome 3. In order to promote application of Ef-cd gene in rice improvement, we studied the photosensitivity and effect of Ef-cd gene on main agronomic traits by using near isogenic lines harboring the gene and their recurrent receptor parents Minghui 63 (MH63), Shuhui 881 (SH881) and Shuhui 527 (SH527). At the same time, application potential of Ef-cd gene in developing early-maturing hybrid rice was evaluated through analysis of main agronomic traits and yield of F₁ combinations from the cross between the near isogenic lines of Ef-cd gene and CMS lines. The results showed that there was no significant difference of reduction of dates to heading in the same early-maturing lines between long-day and short-day conditions. Under natural long-day condition, there were significant differences in dates to heading and plant height between the early-maturing lines and their receptor parents, with 13–21 d earlier and 2.4–10.9 cm shorter in the early-maturing lines than in their receptor parents, respectively. However, there were no significant differences in panicles per plant, spike length, grain number per panicle, seed setting rate, and 1000-grain weight between the early-maturing lines and their receptor parents. It is assumd that Ef-cd gene is a photoperiod-insensitive dominant earliness gene and can significantly accelerate heading, markedly reduce plant height, but does not have significant effects on panicles per plant, spike length, grain number per panicle, seed setting rate, and 1000-grain weight of rice. Days to heading of the hybrid combinations of early-maturing line E527-5-5 with CMS lines G46A, G201A, and G203A were 13–17 d earlier than those of its receptor parent SH527 with the same CMS lines, however, yield of the early-maturing hybrid combinations was 5.8%–7.1% higher as compared with the control cultivar Shanyou 77 with the same mature period. It is also suggested that Ef-cd gene can advance late-maturing hybrid rice to head significantly earlier, and increase the yield of early-maturing hybrid rice with Ef-cd gene. Therefore, Ef-cd gene may have promising application potential in developing early-maturing and high-yielding hybrid rice.

QTL Analysis of Green-Keeping Traits in Rice (Oryza sativa L.) Leaf

XUE Da-Wei;GUO Long-Biao; ZENG Long-Jun; JIANG Hua;GAO Zhen-Yu;LIU Jian;ZHANG Guang-Heng;ZENG Da-Li;QIAN Qian

Acta Agron Sin. 2007, 33(03):  389-393. 

Abstract ( 1899 )   PDF (704KB) ( 1062 )   Save

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Genetic research of green-keeping traits is very important in rice physiological breeding. Green-keeping traits are controlled by multi-genes with major effects and minor modifiers. In this study, a double haploid (DH) population derived from anther culture of ZYQ8/JX17, a typical indica and japonic

Somatic Embryogenesis and Plant Regeneration in Cotton Cultivars from Yellow and Yangtze River Planting Areas

XIE De-Yi;JIN Shuang-Xia;GUO Xiao-Ping;ZHANG Xian-Long

Acta Agron Sin. 2007, 33(03):  394-400. 

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Many restrict factors still remain in cotton genetic transformation, which requires appropriate tissue followed by regeneration. Long tissue culture duration, unpredictability of tissue culture, and a high degree of genotype dependence are more troublesome in plant regeneration of cotton. The objectives of this study were to examine some factors (including hormone combination, salts of ammonium, Fe²⁺ content and genotypes) significantly affect the efficiency of regeneration and transformation in cotton and optimize the somatic embryogenesis of upland cotton using 22 cultivars including 10 cultivars from Yellow River valley, 10 cultivars from Yangtze River valley, and two highly responsible genotypes Coker 201 and YZ^-1. Most of the genotypes showed high regenerability under the IBA/KT hormone regime. NH4+ was necessary during the callus induction and subculture, but it should be omitted and replaced by NO3+ during somatic embryogenesis. The content of Fe²⁺ was the key factor for callus induction and differentiation. The differentiation medium could significantly improve the conversion from the fast growing callus to embryogenic callus with the FeSO₄ concentration of 56 mg L^-1. Under the optimized culture procedure, most of the genotypes collected from the two valleys showed the similar regeneable abilities, except a relative longer time taken during the somatic embryogenesis of cultivars from the Yangtze River valley. The somatic embryogenesis and plant regenerations of eight genotypes(i.e. Ek3, Ek5, Em20, Em23, Ym9, Ym12, Yz73, and Ym1221) firstly obtained.

Winter Wheat Growth Simulation under Water Stress by Remote Sensing in North China

ZHANG Li ;WANG Shi-Li ;;HE Yan-Bo ;MA Yu-Ping;ZHUANG Li-Wei;HOU Ying-Yu

Acta Agron Sin. 2007, 33(03):  401-410. 

Abstract ( 2014 )   PDF (1764KB) ( 1076 )   Save

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Accurate crop growth monitoring and yield forecasting are significant to food security and sustainable development of agriculture. However, Regional crop growth simulation under water stress faces the difficulties in determining the spatial distribution of some model parameters and initial conditions, such as initial available soil water and irrigation. It appears to be a big potential in this field to couple remote sensing data with crop model. In this paper, we proposed a way of combining evapotranspiration derived from satellite remote sensing data with crop grow simulation model (WOFOST) under water stress. Some modifications of WOFOST model were performed with field experimental data to make it applicable in North China Plain. The combination method was first applied to simulate the growth, development and yield formation processes for winter wheat at two sites, Tai’an and Zhengzhou, during the growing season from 2001 to 2002. According to the results of sensitivity analysis, the initial available soil water was chosen to be recalibrated by observed evapotranspiration derived from MODIS data based on SEBS model (Surface Energy Balance System). Also the biomass at reviving and irrigation at heading stage were selected to re-estimated by observed SAVI and evapotranspiration, considering over-winter process and the importance of irrigation on winter wheat yield formation in North China. The difference between observed and simulated evapotranspiration/SAVI was minimized by re-initializing/re-parameterizing three chosen initial conditions/parameters with an optimization program (FSEOPT). The estimated values of initial available soil water and irrigation showed good agreement with observations at the two sites. And the relative errors of simulated dry matter weight of gross above-ground and storage organ were reduced also. On the basis of the regionalization of weather data, model parameters, and initial conditions, we used this method to estimate winter wheat yields in North China during the growing season from 2001 to 2002 at the scale of 0.25 degrees, especially for Henan, Hebei, and Shandong provinces. It was showed that both soil water estimates and final winter wheat production estimates were consistent with ground measurements since the initial available soil water, biomass at reviving and irrigation at heading stage were recalibrated by remote sensing data. The relative root mean square error (RRMSE) decreased from 0.63 to 0.20 for the yield from 32 experimental sites, which distribute uniformly in North China Plain. Also the aggregated yields for three provinces were improved, with relative errors －4.9%, 4.5%, and 8.6%, respectively. These results illustrated that the evapotranspiration derived from MODIS data could be used to improve the winter wheat yield estimate under water stress on a regional scale. Further study should focus on better understanding of processes, error accumulation, and improvement on validation of both evaportranspiration derived from MODIS data and simulated yields for winter wheat.

Correlation Analysis of Starch RVA Profiles and Cooking Physical-chemical Indices of Different Cultivars（Lines）and DH Populations in Japonica Rice

ZHU Man-Shan;TANG Shu-Zhu ;;GU Ming-Hong

Acta Agron Sin. 2007, 33(03):  411-418. 

Abstract ( 2110 )   PDF (667KB) ( 1063 )   Save

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Starch pasting viscosity tested by Rapid viscosity Analyser (RVA) and cooking physical-chemical indices are two kinds of important evaluation parameter for the eating and cooking quality of rice. It is important to investigate these indices to select high quality rice cultivar. The objectives of this study were to investigate these rice quality indices and analyze their correlations using 18 japonica cultivars (lines) from Jiangsu Province of China, 18 Japanese Japonica cultivars (lines) and three double haploid (DH) populations derived from the cross between Wuyunjing 8 (a Jiangsu japonica cultivar) and Yueguang, Nongken 57, Xiaoqianyou (three Japanese japonica cultivars), respectively. The results showed as follows: (1) There were no significant difference in breakdown (BDV), setback(SBV) and gel consistence (GC) between cultivars(lines) of Jiangsu of China and Japan, but Japanese cultivars(lines) had higher peak viscosity (PKV), hot paste viscosity (HPV), cold paste viscosity (CPV), consistence(CSV) and amylose content (AC), and lower pasting temperature (PaT). Jiangsu and Japanese cultivars (lines) could be clustered into four types based on starch RVA profiles. The cultivars (lines) of the first type including six Japanese cultivars (lines) with superior eating quality had lower HPV, CPV, SBV and CSV, and higher PaT than those of the fourth type including six Jiangsu cultivars (lines) with inferior eating quality. (2) All the RVA profile characteristics and cooking physical-chemical indices of three DH populations had wide genetic variations and were higher than high-parent values or lower than low-parent values, among which SBV had largest coefficient of variation. (3) The tight relationship among RVA profiles was found. There were very significant（P＜0.01） positive correlations among PKV, HPV and CPV, significant （P＜0.05） or very significant positive correlations between PKV and BDV, HPV and BDV, respectively, very significant positive correlations between HPV and CSV, CPV and CSV, SBV and CSV, respectively, and very significant negative correlation between BDV and SBV. Additionally, in three DH populations, there were also same very significant positive correlation between CPV and BDV, significant or very significant positive correlations between PaT and PKV, PaT and BDV, respectively, and very significant negative correlation between PaT and SBV. (4) Cooking physical-chemical indices had tight relationship with starch RVA profiles in three DH populations. AC was significantly positively correlated to SBV and significantly or very significantly negatively correlated to PaT. GC was significantly and positively correlated to PKV, BDV and PaT, respectively, and very significantly and negatively correlated to SBV. The results suggest that HPV, CPV, SBV, CSV and PaT can be used as referenced indices in eating quality selection of Japonica rice.

Application of Digital Image Processing for Determination of Vertical Distribution of Biomass in the Canopy of Winter Wheat

SHAN Cheng-Gang ;LIAO Shu-Hua ;GONG Yu ; LIANG Zhen-Xing ;WANG Pu ;

Acta Agron Sin. 2007, 33(03):  419-424. 

Abstract ( 1873 )   PDF (439KB) ( 1004 )   Save

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The vertical distribution of biomass, which indicated the characteristics of quantity and structure in canopy, is an important index of diagnosis and management for crop growth. However, traditional measurements are time-consuming and labor intensive and can result in significant mechanical damage to plants, such as layer upon layer cut method. The image processing technologies, which may provide more efficient and no-destructive methods for measurement, have recently appeared in the agronomic literature. This paper focused on the determination of biomass vertical distribution in the canopy of winter wheat, based on digital image processing technology. The digital images (2 272 by 1 706 pixels) were taken with digital camera of winter wheat rows in the field plots of an experiment during the 2004 to 2005 growing season. Excess Green image segmentation method was used to separate wheat population and background. At the same time, relative biomass weight was measured using layer upon layer cut method, and the distance between neighbor layers was 20 cm. The image pixels of a single row and biomass could fit regression relationship (R2D1=0.9682) much better than those of multiple rows and biomass. The regression relationship between the image pixels and dry matter weight much better than those and fresh matter weight. The estimating functions were established between biomass and pixel number (PN) in each layer (Y = 6×10-5X + 24.72), and between effective biomass and green pixel number (LGPN) in each layer (Y = 7×10-5X + 25.09), and meanwhile the vertical distribution of effective biomass and dynamic of winter wheat canopy under different management conditions was analyzed qualitatively with LGPN. Finally, an index, namely, image pixel vertical distribution index (I), with which vertical distribution of canopy biomass of winter wheat could be analyzed quantitatively, was determined. The results show that the application of digital image processing has significant potential for determination of vertical distribution of biomass in the canopy of winter wheat, and is one of the quick, real time and almost no-destructive measurements.

Drought-resistance Identification of Dongxiang Common Wild Rice (Oryza rufipogon Griff.) in Whole Growth Period

HU Biao-Lin;YU Shou-Wu;WAN Yong;ZHANG Zheng;QIU Bing-Yu;<SPAN lang=EN-US style=

Acta Agron Sin. 2007, 33(03):  425-432. 

Abstract ( 1963 )   PDF (765KB) ( 1146 )   Save

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The drought and scarcity of water resource are more and more serious, and restrict agricultural development, specially rice production in China. Dongxiang common wild rice distributed in the most north region all over the world contains plentiful genetic diversity and excellent genes encoding drought resistance, cytoplasm male sterility (CMS), cold tolerance, fertility restoration, and so on. Screening drought resistance of dongxiang common wild rice is important for breeding rice with drought resistance and creating new drought resistance resource in current cultivated rice.
With the water stress and non-stress treatments designed, twelve morphological and physiological traits correlating with drought resistance were monitored in whole growth period for the back-cross inbred line population (R974//DongYe/R974) BC₁F₅, which were plant height (PH), tillers number per plant (TNP), effective tillers number per plant (ETNP), spikelets per panicle (SP), filled spikelets per panicle (FSP), length of panicle (LP), panicle density (PD), 1000-grain weight (TGW), seed setting rate (SR), grain weight per plant(GWP), leaf relative water content (LRWC), and level for rolling leaf (LRL). GWP is the most sensitive trait that is influenced by drought. Single variable stepwise regression, path analysis, gray correlative analysis, and multiple partial correlations analysis were conducted between the relative value of various traits and drought resistance coefficient. The results showed that six traits including LRWC, TNP, ETNP, TGW, PH, and ETNP significantly influenced the drought resistance and could be the indices to identify the drought resistance in rice. The D value of six traits elected was comprehensively used to evaluate the drought resistance by subordinate function values analysis, the results showed six index traits were feasible to predict the drought resistance in rice for whole growth stage. Four different drought resistance evaluated methods were compared, which indicated the drought resistance index is the best one for drought resistance direct evaluating.

Response of Plant Height to Free Air CO₂ Enrichment in Rice (Oryza sativa L.)

FAN Gui-Zhi ;;CAI Qing-Sheng ;;WANG Chun-Ming;WAN Jian-Min;ZHU Jian-Guo

Acta Agron Sin. 2007, 33(03):  433-440. 

Abstract ( 1891 )   PDF (872KB) ( 962 )   Save

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Free air carbon dioxide enrichment (FACE) technique is capable of providing a means by which the environment around growing plants may be modified to realistically simulate future concentrations of atmospheric CO2. The plant growth and development, as well as its height, biomass, and yields can be accelerated and enhanced under FACE. Identifying genomic regions influencing the response of plant height and its components to elevated CO₂ will be useful for us to understand the genetic response to changed CO₂ environment and select materials or cultivars adapting to future elevated CO2 atmospheric environment in plant height characteristics. A mapping population of 65 indica (IR24) chromosome segment substitution lines (CSSLs) with japonica (Asominori) background was used to detect quantitative trait locus (QTL) for plant height and its components containing panicle length and various internode lengths under ambient atmosphere CO₂ concentration (Ambient, about 370 µmol CO2 mol^-1) and FACE (exceed ambient CO₂ concentration about 200 µmol mol^-1). The main results indicated that plant height and its components of Asominori and IR24 under FACE were significantly different from these of Ambient at 1% probability level. Both positive and negative responses to elevated CO₂ in plant height and its components of CSSLs were observed under FACE. Among them, eight CSSLs largely responded to elevated CO₂, they were AI63 (increased 14.2 cm) and AI44 (reduced 4.54 cm) in plant height, AI9 (increased 3.56 cm) and AI12 (reduced 2.39 cm) in panicle length, AI39 (increased 15.74 cm) and AI27 (reduced 1.49 cm) in the first internode, AI32 (increased 8.09 cm) and AI53 (reduced 3.00 cm) in the second internode. Fourteen QTLs and 15 QTLs were detected under FACE and Ambient, respectively. Among them, 5 QTLs, named qPH6^-4, qPH8^-4, qPL8^-4, qPL12^-4, and qLFN6^-4, were simultaneously detected under FACE and Ambient, the others were detected only under one CO₂ level. Three QTLs, named qPH6^-4QE, qPH8^-4QE and qLSN5^-4QE were found to have gene x environment interaction effects significantly. It is suggest that some new QTLs for plant height and its components can be detected under elevated CO₂ condition, the QTLs being detected under unitary CO₂ condition, natural ambient atmosphere or FACE are sensitive to CO₂ concentration, plant height is controlled by the interaction effect between genotype and CO₂ concentration.

QTL Analysis of Seed and Pod Traits in Soybean RIL Population

WANG Xian-Zhi ; ZHANG Xiao-Juan ; ZHOU Rong ; SHA Ai-Hua ;WU Xue-Jun ;CAI Shu-Ping ;
QIU De-Zhen ;ZHOU Xin-An ;


Acta Agron Sin. 2007, 33(03):  441-448. 

Abstract ( 2119 )   PDF (654KB) ( 1241 )   Save

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Seed and pod traits are important factors affecting soybean yield, which are controlled by polygenes. The previous studies have identified many QTLs associated with yield and its component. The previous genetic analysis also pointed out that improving the seed and pod traits was an efficient way to increase soybean yield, but there was little QTL analysis on seed and pod traits. In order to find out steady and repeatable QTLs of these traits, 255 recombinant inbred lines (RILs) derived from the cross between Zhongdou 29 and Zhongdou 32 were used to map QTLs of seed and pod traits in two years. ANOVA analysis showed that the characters of one-seed pod, four-seed pod, and number of seeds per pod had significant year-line interaction in two years, while number of pods and number of seeds had not. A genetic linkage map of soybean genome was constructed, which consisted of 23 linkage groups with 98 SSR markers. The Interval Mapping method(IM) and Composite Interval Mapping method(CIM) were used to identify QTL associated with one-seed pod, four-seed pod, number of pod, number of seeds, and number of seeds per pod. A total of 51 QTLs for these traits were identified in two years using different statistic methods. Among them, 24 QTLs explained the phenotypic variance ranging from 5% to 80% by using interval mapping method, and 27 QTLs accounted for 4% to 73% of the variance for the 5 traits using CIM. Tow QTLs of four-seed pod and tow QTLs of number of seeds per pod were found in tow years with different methods. These results can be used for the further fine mapping and marker assisted selection of these traits.

Relationship between the Efficient Amount of Nitrogen Application for Grain Filling and the SPAD Value at Full Panicle Stage in Mid-Season Hybrid Rice

XU Fu-Xian; XIONG Hong;ZH U Yong-Chuan; ZHANG Lin;WAN Xian-Qi; LIU Mao;WANG Gui-Xiong

Acta Agron Sin. 2007, 33(03):  449-454. 

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Many studies on the sensibility of grain filling to nitrogen application at full panicle stage in rice have been conducted, with a lot of differences in results. Perhaps, it is related to different nutrition levels of nitrogen in plant at full panicle stage, on which there have been few studies. In this paper, the relationship between the efficient amount of nitrogen application for grain filling (NAGF) and the source-sink structure at full panicle stage was investigated with “Ⅱ-you 602”, a combination of mid-season hybrid rice under different amounts of nitrogen application in basic fertilizer, tillering fertilizer, and NAGF, expecting to establish a theoretical basis for efficient nitrogen application in high yield rice cultivation. There was highly significant correlation between the effect of yield increase by NAGF and nutrition level of plant. The efficient amount of NAGF depended on SPAD values of the first leaf from top, leaf nitrogen content, and total No. of spikelets per m² at full panicle stage. There were highly significant negative correlations between the efficient amount(y, kg ha^-1) of NAGF and SPAD values (x) of the first leaf from top at full panicle stage, y = －30.7980x + 1340.9 and R² = 0.9114. When the SPAD value of the first leaf from top at full panicle stage was over 43.5, as a critical diagnosing index in rice production, NAGF was not necessary.

The Relationships of Water Use Efficiency with Leaf Physiological Characteristics in Gaodan Grass

GAO Ju-Lin;ZHAO Tao;WANG Zhi-Gang;GUO Gai-Ling;FAN Lei

Acta Agron Sin. 2007, 33(03):  455-460. 

Abstract ( 1759 )   PDF (412KB) ( 984 )   Save

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It is well known that water shortage is a main limited factor to crop production, therefore it is important to improve the crop water use efficiency (WUE), especially under water limited condition. Gaodan grass, a hybrid of sorghum and Sudan grass, is a widely planted forage crop in Inner Mongolia, where water deficiency is a common problem. The primary aim of this study was to investigate the relationships between WUE and leaf physiological characteristics in Gaodan grass, and furthermore to understand the potential for increasing Gaodan grass water use efficiency. From booting to flowering stages of Gaodan grass under different water supply conditions, water use efficiency (WUE), net photosynthetic rate (P_n), transpiration rate (T_r), stomata conductance (G_s), intercellular CO₂ concentration (C_i), leaf temperature (T_l), and relative water content of leaves (RWC) were measured. The results showed that the water use efficiency presented a quadratic curve with photosynthetic rate. When Pn was 27 µmol CO₂ m^-2 s^-1, and Tr was 3.5–4.0 mmol H₂O m^-2 s^-1, WUE reached maximal point (8.4 µmol CO₂ mmol^-1 H₂O). The relationship between the photosynthetic rate and the transpiration rate presented a parabolic curve. The transpiration rate at the maximal photosynthesis rate was a critical value, beyond which the water utilization would be luxurious. When the stomatal conductance was 0.4 mol H₂O m^-2 s^-1，WUE reached 8.39 µmol CO₂ mmol^-1 H₂O, if Gs was higher than 0.4 mol H₂O m^-2 s^-1 WUE would be decreased. It is necessary to take some measures for increasing stomatic resistance and inhibiting transpiration, so as to save water and improve photosynthesis and yield as well. The increase of temperature promoted the photosynthesis and transpiration, when temperature was in the range of 35℃ to 36℃, the photosynthetic rate reached the maximum. With the increase of RWC, WUE was increased, when RWC was 84%–86%, WUE was the maximum. Proper N fertilization was also proved to increase P_n and G_s, and WUE further.

Analysis of Factors Influencing the Genetic Diversity Evaluation Using Two Soybean[Glycine max（L.）Merr.] Collections from Hunan and Hubei

GUAN Yuan ;E Wen-Di ; WANG Li-Xia;GUAN Rong-Xia;LIU Zhang-Xiong ;CHANG Ru-Zhen ;QU Yan-Ying ;QIU Li-Juan ;

Acta Agron Sin. 2007, 33(03):  461-468. 

Abstract ( 2162 )   PDF (641KB) ( 1000 )   Save

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Accessions from Hunan and Hubei provinces in the Chinese soybean pre-core collection were analyzed with SSR markers to determine an optimal strategy in genetic diversity evaluation. The results showed that when analyzed with the same sampling ratio, the number of alleles in accessions from Hubei province was higher than those from Hunan province, however the difference was not up to significant level in genetic diversity index. When analyzed with same sample size by random sampling, accessions from Hunan province were higher both in number of alleles and diversity index than those from Hubei, while there was no significant difference between them as sampled based on cluster. Accessions from Hubei were larger in number of alleles than those from Hunan when sampled by the same genetic diversity index. Genetic diversity index was influenced by sample size as we concluded, and we deduced that in genetic diversity analysis, a minimum of 50–60 accessions (9.0%–10.8% percent of total accessions) was required to represent most of genetic variation, so that it could explain the total genetic variation. An adjustment of the formula for Shannon index was also proposed after a set of analyses based on accessions from Hunan and Hubei. And with it, accessions from Hubei showed higher genetic diversity than those from Hunan province.

Photosynthetic Characteristics of Bt or CpTI-Bt Transgenic Cotton at Seedling Stage

SUN Cai-Xia ;QI Hua ; SUN Jia-Qiang ; ZhANG Li-Li ;MIAO Lu

Acta Agron Sin. 2007, 33(03):  469-475. 

Abstract ( 1865 )   PDF (522KB) ( 1198 )   Save

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Photosynthesis is an important physiological process related to yield production and biomass accumulation in plants. With the research, development and application of genetically modified (GM) crops in the world, their risk assessment has been paid an increasing attention. In order to find out effects of exogenous genes on photosynthesis in transgenic plants, photosynthetic characteristics of transgenic Bt (Z30) and CpTI-Bt (CCRI41 and SGK321) cotton at seedling stage were studied by pot experiment. The results showed that the changes of stomatal conductance, transpiration rate and intercellular CO2 concentration in the leaves of Bt and CpTI-Bt transgenic cotton were not obvious in comparison with non-transgenic cotton (Z16, CCRI23 and SY321, respectively) and differed among different cotton cultivars. The difference of net photosynthetic rate between Bt transgenic cotton Z30 and non-Bt cotton Z16 was significant. The RuBPcase activity was decreased significantly and the GO activity increased significantly in the leaves of all tested transgenic cotton in comparison with non-transgenic cotton. But there were not significant differences in the content of Chlorophyll a, Chlorophyll b, Chlorophyll a/b, and the total Chlorophyll content between transgenic and non-transgenic cotton. The responses of photosynthetic rate to light intensities in mature cotton leaves were also measured under different light intensity conditions (the light intensities were 0, 10, 20, 40, 60, 80, 100, 200, 400, 600, 800, 1 000, and 1 200 μmol m^-2 s^–1). The parameters of apparent quantum yield, maximum net photosynthetic rate, apparent dark respiration rate, 1ight compensation point and 1ight saturation point were calculated by model fitting. The possible changes of these parameters were observed at a certain extent. But the results still need to be validated through farther test. From these results, the processes of photosynthesis and respiration regulated by RuBPcase and GO are changed possibly. The analysis by combination of dry biomass and photosynthetic characteristics studied in this experiment indicated that the response of biomass accumulation to genetical modification by exogenous genes of Bt and CpTI in transgenic cotton was related to both photosynthesis and other processes which were not studied in this experiment. The unanticipated effects of transgenic crops would be more uncertain and complex along with diversification of transgenic genes.

UV-Vis Spectrum Differences of Polyphenols between Yellow and Black Seed Coats of Brassica juncea

ZENG Kui ;LIU Zhong-Song ; ;LONG Sang ;YAN Ming-Li

Acta Agron Sin. 2007, 33(03):  476-481. 

Abstract ( 2049 )   PDF (387KB) ( 1143 )   Save

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The seed coat color has been thought to be closely concerned in the polyphenols. The content differences of polyphenols between yellow and black seed coats have been determined in Brassica napus, but not in Brassica juncea. In addition， the molecular structure differences of polyphenols between yellow and black seed coats seem not to be reported in Brassica. Plant polyphenols are a large number of complex compounds containing hydroxyls, they play an important role in physiological actions in plant organism. To find out the content differences and the molecular structure differences of polyphenols between yellow and black seed coats, and the relationship between the polyphenols’ differences and the seed coat color differences in B. juncea the yellow and black seed coats of inbred lines of B. juncea were used as the research materials， the solutions of the polyphenols extracted from the yellow and black seed coat samples with 5% HCl-CH3OH were scanned by the UV-Vis spectrophotometer(UV-1600) at wavelength of 200–300/800 nm, and the contents of polyphenols were determined through absorption spectrometry with either gallic acid or tea catechin standard， respectively. The results showed that the content of polyphenols of the yellow seed coat was about 90% of that of the black seed coat. While the content of polyphenols of the yellow seed coat was about 10% of that of the black seed coat in B. napus. Therefore the high content of polyphenols might be the main factor resulting in the character heredity stability of yellow rapeseed in B. juncea. In vanillin test the black seed coat turned red in color， the yellow coat remained the original color. It could be deduced that there are the flavanol-phenolic molecules that their ring C should contain 3-OH among the polyphenols of the black seed-coat, while there are not these molecules among the polyphenols of the yellow seed-coat. After the shift reagents were added in the solutions of the polyphenols extracted from the yellow and the black seed-coats， the spectral absorption band Ⅰ&Ⅱ shifted. On basis of the shift direction and the shift quantity of the spectral band Ⅰ&Ⅱ it could be deduced that phenolic ring A of the flavanol-phenolic molecules might contain monohydroxyl (7-OH) and o-dihydroxyl among the polyphenols of the yellow and the black seed-coats, respectively. It is proposed that the structural differences of the polyphenols might be the major factor resulting in the color differences between the yellow and the black seed coats in B. juncea. These results above may be significant not only in the yellow rapeseed breeding in B. juncea but also in trying to solve the unstable character heredity of the yellow rapeseed in B. napus.

Effects of Nitrogen, Potassium and Glycinebetaine on the Lipid Peroxidation and Protective Enzyme Activities in Water-Stressed Summer Maize

ZHANG Li-Xin ; LI Sheng-Xiu ;

Acta Agron Sin. 2007, 33(03):  482-490. 

Abstract ( 1883 )   PDF (721KB) ( 1082 )   Save

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A pot experiment was conducted under water stress and adequate water-supplying conditions with two cultivars of maize Shaandan 9 (drought-resistant) and Shaandan 911 (non-drought-resistant) to study the effects of nitrogen, potassium and glycinebetaine on lipid peroxidation and protective enzyme activities in maize leaves at different growing stages for revealing their biological functions in the rise of crop resistance to drought by raising activities of these protective enzymes. Results showed that under the water stress condition, activities of superoxide dismutase (SOD), catalase (CTA) and peoxidase (POD) in leaves were significantly reduced while malondialdehyde (MDA) content was increased for both cultivars, but the decline was more obvious for the non-drought resistant one. Activities and variation of SOD, CTA and POD were higher while MDA content was lower for the drought resistant cultivar (Shaandan 9) than those for the non-drought resistant cultivar (Shaandan 911). The lower activities of SOD, CTA and POD at seeding stage than those at elongation and heading stages showed that the response of two cultivars to water stress was weaker at earlier than at later stages. Of these protective enzymes, activities of SOD and POD reached their peak later than that of CTA. MDA content followed a changing pattern of “rise-fall-rise” in the entire maize growth period. Applications of nitrogen, potassium and glycinebetaine raised the activities of SOD, CTA and POD while decreased the MDA content, and thus alleviated water stress effect. Under the water-stressed condition, addition of N fertilizer significantly increased activities of SOD, CTA, POD and decreased MDA content for the non-drought resistant cultivar with a significant difference among N rates. The significant response of drought resistant cultivar to N addition was merely found at low N rate. For high N rate, activities of SOD, CTA and POD were significantly decreased whereas MDA content was increased at earlier growth stage. However, at later growth stage, there was no significant difference between two N rates. Glycinebetaine and K fertilizer exhibited more significant biological function than N fertilizer in the rise of protective enzyme activities under the water stress condition. In contrast, with adequate water supply, effects of N and K fertilization significantly decreased, and the function of glycinebetaine even vanished. All the results suggest that addition of nitrogen, potassium and glycinebetaine make a great contribution to improvement of the protective enzyme activities and lipid peroxidation metabolism.

Molecular Mapping of QTL for Resistance to Maize Ear Rot Caused by Fusarium moniliforme

ZHANG Fan ;WAN Xue-Qin ; PAN Guang-Tang ;

Acta Agron Sin. 2007, 33(03):  491-496. 

Abstract ( 1954 )   PDF (471KB) ( 1185 )   Save

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Maize ear rot, mainly caused by Fusarium moniliforme, is one of the most destructive diseases of maize in the world. Infected maize is lower yielding and contains toxins that are dangerous to livestock and human. The aims of this study were to identify quantitative trait loci (QTL) associated with genetic resistance to F. moniliforme, their positions and effects in the maize genome; investigate the consistency of QTL across two environments and their utilization in a marker-assisted selection programme. A previous genetic map containing 88 AFLP and 151 microsatellite markers and 230 F₂ plants were used for QTL mapping in Maize. QTL analysis was performed using joint composite interval mapping. In Ya’an, six QTL conferring Fusarium moniliforme ear rot resistance on chromosomes 2, 3, 4, 6, and 9 were detected and explained 8.3%–25.7 % of the phenotypic variance; while in Mianyang, four QTL were identified on chromosomes 1, 6, 7, and 9 that accounted for 11.3%–26.4% of the total phenotypic variance. Two QTLs on chromosomes 6 and 9 were identified consistently in both environments, which revealed that resistance to F. moniliforme was determined by genetic factors. Three QTLs on chromosomes 1, 6 and 7 that accounted for 8.9%–17.2% of the total phenotypic variance were detected using the mean resistant disease index of two locations. QTL mapping results will be helpful to further understand genetic basis of ear rot resistance in maize and lay a basis for marker-assisted selection for the resistance species.

Nitrogen Metabolic Characteristics in Rice Genotypes with Different Nitrogen Harvest Index (NHI)

CHENG Jian-Feng ; DAI Ting-Bo; CAO Wei-Xing ; ; JIANG Dong ; PAN Xiao-Yun

Acta Agron Sin. 2007, 33(03):  497-502. 

Abstract ( 2215 )   PDF (519KB) ( 1104 )   Save

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Nitrogen harvest index (NHI), defined as ratio of nitrogen accumulation in economic organs to whole plant at harvest, is an important index for evaluating nitrogen utilization efficiency, but less information is available on its physiological mechanisms and regulation methods in rice cultivation. Pot experiment was conducted using three rice genotypes including 4434 (low NHI), Dianrui 302 (medium NHI) and Yuchi 231 (high NHI) to elucidate nitrogen metabolism characteristics in leaves, panicle internodes and grains during grain filling and their relationships to NHI. The results showed that change patterns of grain yield, harvest index and nitrogen accumulation in grains were consistent with that of NHI among three rice genotypes, and all the parameters were the highest in Yuchi 231. Highly significant differences were observed in nitrogen translocation amount after anthesis in plants with the order of 4434 < Dianrui 302 < Yuchi 231, while rate of N translocation and contribution rate of translocated N to grain had no significant difference among three genotypes. At maturity, the contents of total nitrogen, protein nitrogen and non-protein nitrogen in leaf-stems and grains exhibited the order of 4434<Dianrui 302< Yuchi 231 with significant genotypic differences for the parameters but non-protein nitrogen. Protein nitrogen accumulation in leaf-stems of Yuchi 231 was significantly lower than those of 4434 and Dianrui 302, while that was significantly higher in grains, which suggested that higher nitrogen accumulation in grains was a key characteristics of the rice genotype with high NHI. Moreover, the activities of glutamine synthetase (GS) and glutamate synthase (GOGAT) in leaves of Yuchi 231 were highly significantly higher than those of 4434 and Dianrui302 at filling, which would be in favor of the formation of free amino acids in leaves and its translocation to grain, and resulted in higher bleeding intensity and free amino acid content in panicle internodes and providing the substrate for nitrogen accumulation in grains. Meantime, activities of GS and GOGAT in grains were higher in Yuchi 231 than in 4434 and Dianrui 302 which accelerated more proteins synthesis in grains. Stepwise regression indicated that free amino acid content in bleedings of panicle internode was a main physiological index involving in nitrogen assimilation related to NHI. The above results suggest that higher post-anthesis nitrogen translocation amount, protein nitrogen accumulation in grains and free amino acid content in bleedings of panicle internode are more beneficial indicators for enhancing rice NHI in nitrogen management and genetic improvement.

RESEARCH NOTES

Genetic Diversity of Waxy Gene in Chinese Wheat Landraces

DU Xiao-Yan ;HAO Chen-Yang;ZHANG Xue-Yong ; ; MA Zheng-Qiang ;YOU Guang-Xia;WANG Lan-Fen; DONG Yu-Shen

Acta Agron Sin. 2007, 33(03):  503-506. 

Abstract ( 1938 )   PDF (1167KB) ( 996 )   Save

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A total of 1 739 Chinese wheat landraces were screened for the Waxy gene mutations with two STS, one SSR and one gene specific marker published in previous researches. Among of the landraces, 3 were null Wx-A1 mutants, 25 were null Wx-B1 mutants, and 3 were null Wx-D1 mutants. Different null types of Waxy genes were also certified by SDS-PAGE of waxy proteins, containing that these markers were effective to verify mutant and normal alleles at waxy loci. These markers can also be used in marker-assisted selection in breeding program. Furthermore, based on our findings, we recommend some accessions with different Waxy mutations to breeders. Genotypes of Waxy genes of these materials were also released in this paper.

Primary Study on Gene Differential Expression of Pest-resistant Cotton Hybrids between Different Heterosis Crosses

XING Chao-Zhu ;YU Shu-Xun ;; ZHAO Yun-Lei ; GUO Li-Ping ;ZHANG Xian-Long ; MIAO Cheng-Duo ; WANG Hai-Lin

Acta Agron Sin. 2007, 33(03):  507-510. 

Abstract ( 1947 )   PDF (304KB) ( 1004 )   Save

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Leaf cDNA of 3 pest-resistant cotton crosses with remarkable different yield heterosis and their parents in 4 growth stages were amplified by DDRT-PCR (The mRNA Differential Display) with 45 primers combinations. The results were as follows: The proportions of genes differential expression between F1 and their parents were degressive tendency from square stage to boll stage in these crosses. The percentages of genes differential expression in the high heterotic cross were higher than those in the low heterotic crosses in four growth stages, which showing a closely relationship between gene differential expression and heterosis occurrence. The percentages of M3 (bands expressed only F₁) in the high heterotic crosses surpassed those in middle or low heterotic crosses at three earlier growing stages, which suggested M3 played an important role in yield heterosis occurrence. M4 (bands expressed in one parent and F1) was the main expression pattern in gene differential expression, but varied within narrow range in four growing stages, which indicated no remarkable correlation between yield heterosis and M4.

Gene Mapping of a Sub-Red Mutant in Upland Cotton

SONG Zhen-Yun ;YANG Zhi-Min ; ; CHEN Xu-Sheng ;

Acta Agron Sin. 2007, 33(03):  511-513. 

Abstract ( 1819 )   PDF (755KB) ( 869 )   Save

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Sub-red mutant, used as a female parent, was crossed with GK19 to generate F₁ plants, which surpassed their parents with its good photosynthesis efficiency. In this sense, sub-red mutant would be regarded as a potentially elite germplasm. Molecular markers linked to sub-red mutant gene are of great importance for fine mapping the sub-red gene and cloning. To screen for SSR markers closely linked to sub-red gene in upland cotton, we developed the F₁ and BC₁ from intraspecific crosses with the parents mentioned above. Screening of 419 SSR markers, covering all the identified chromosomes and most linkage groups of cotton, was performed by bulked segregation analysis, revealing informative SSRs, mapped on the above populations afterwards. One co-dominant SSR marker BNL2634 was identified closely linked to the sub-red gene (tentatively named as Rs), with an estimated distance of 10.3 cM, depending on the population used. The other five markers linked to Rs were CIR393, with a loose linkage to Rs (approximately 29.1 cM), CIR335, BNL1597, NAU1362, and NAU1048, showing the Rs gene to be located on cotton chromosome 7.

Effects of Planting Density on Activities of Nitrogen Metabolism Enzymes in Flag Leaves and Grain Protein Content in Winter Wheat with Two Spike Types

MA Dong-Yun;GUO Tian-Cai;ZH A Fei-Na;WANG Chen-Yang;ZHU Yun-Ji;WANG Yong-Hua

Acta Agron Sin. 2007, 33(03):  514-517. 

Abstract ( 1793 )   PDF (275KB) ( 986 )   Save

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Two winter wheat（Triticum aestivum L.） cultivars, Yumai 49-198 with multi-spike and Lankao Aizao 8 with large spike were used to investigate effects of planting density on the activities of enzymes related to nitrogen metabolism and grain protein content. We found that the planting density significantly affected the activities of enzymes. For both cultivars before 15 days after anthesis, the activities of glutamine synthetase (GS) and glutamate synthase (GOGAT) in flag leaves were improved with the increase of planting density, and meanwhile nitrate reductase (NR) activity in flag leaves was the lowest in middle density treatment. In a certain range, the grain protein content was enhanced with the increase of planting density for both cultivars. The results indicate that the increase of the activities of enzymes related to nitrogen metabolism benefits the accumulation of grain protein.

Relationship between Canopy Hyperspectral Index and Leaf Nitrogen Accumulation in Cotton

WU Hua-Bing;ZHU Yan;TIAN Yong-Chao; YAO Xia; LIU Xiao-Jun; ZHOU Zhi-Guo;CAO Wei-Xing

Acta Agron Sin. 2007, 33(03):  518-522. 

Abstract ( 1905 )   PDF (370KB) ( 1078 )   Save

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It is very important to develop nondestructive method for estimating nitrogen status and growth characters in cotton. Based on the canopy hyperspectral reflectance and derived hyperspectral vegetation index, we analyzed the quantitative relationships between leaf nitrogen accumulation and canopy reflectance spectra in different cotton cultivars under varied N rates, and put forward the sensitive parameters and monitoring equations for leaf nitrogen accumulation. The results showed that the leaf nitrogen accumulation and canopy hyperspectral reflectance significantly changed with levels of nitrogen fertilization. The sensitive wavebands of leaf nitrogen accumulation were 600–700 nm of red valley and 750–900 nm of near infrared wavebands, and the leaf nitrogen accumulation was high significantly related to NVD672 of canopy reflectance spectra, and an integrated equation could be used in different cultivars. These results provide technical approach for monitoring plant nitrogen status and guiding precision nitrogen management in cotton production.