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Table of Content

    10 February 2006, Volume 39 Issue 02
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES
    Verification of the Effects of QTLs for Grain Weight and Yield in Lowland Rice and Upland Rice
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    Scientia Agricultura Sinica. 2006, 39(02):  219-224 . 
    Abstract ( 2954 )   PDF (280KB) ( 2171 )   Save
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    【Objective】Accuracy mapping of the target traits is the prerequisite of the effectiveness of marker-assisted selection (MAS). 【Method】 Two previously identified quantitative trait loci (QTLs) conferring 1000-grain weight (TGW) and grain yield per plant (YP), on the same location of chromosome 6, designated tgw6.1 and yp6.1 respectively, were chosen as target QTLs to verify the QTL effects by using three segregating populations through marker-assisted selection (MAS). Three segregating populations (BC1, F2) derived from crosses between an upland rice variety (IRAT109, donor of target QTLs) with big grain weight and high yield potential, and two lowland rice varieties (recipients) with small grain weight and better grain quality, were used in this study. 【Result】The results showed that QTLs conferring bigger TGW and higher YP were genetically stabilized in different populations with different genetic backgrounds. The differences between the means of TGW of individuals carrying and not carrying donor's favorable alleles of tgw6.1 were 3.18﹣3.62 g, significant at 1% level. The phenotypic effects of MAS for tgw6.1 were 13.94%﹣18.15%. The differences between the means of YP of individuals with and without donor's favorable alleles of yp6.1 were 5.04﹣8.18 g, significant at 5% or 1% level. The phenotypic effects of MAS for yp6.1 were 34.89%﹣58.88%. Compared the phenotypic effects based on one or both of the flanking markers of target QTLs, the results showed that it was more reliable to select with both of the flanking markers when the interval of the target QTL was longer, (such as the interval of TGW and YP QTL, 13.5 cM); when the map distance between the marker and the target QTL was very short ( such as RM527 in present study, 1.5 cM ), it was also more effective to select with the marker which was nearer to the target QTL. Moreover, the phenomena of QTL with pleiotropic effects and the effectiveness of MAS for complex traits were also discussed. 【Conclusion】In this paper, the reality and accuracy mapping of TGW and YP QTLs and their phenotypic effects were verified. The feasibility of MAS based on QTL for complex traits such as drought resistance was confirmed.
    Screening and Localization of SSR Markers Related to Salt Tolerance of Somatic Hybrid Wheat Shanrong No.3
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    Scientia Agricultura Sinica. 2006, 39(02):  225-230 . 
    Abstract ( 1721 )   PDF (469KB) ( 2218 )   Save
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    【Objective】 Screen and localize the SSR markers related to salt tolerance trait in wheat variety Shanrong No.3. 【Method】Using a novel salt-tolerant wheat asymmetric somatic hybrid variety Shanrong No.3 as experimental material, the F2 population of hybridized combination 01 was constructed from sexual crossing between Shanrong No.3 and salt-sensitive variety Jinan 17. In combination to the SSR map of wheat, the seedlings of the population were used to determine the salt tolerance and the loci related to the salt tolerance was tagged by microsatellite (SSR) and BSA (bulked segregant analysis). 【Result】Genetic analysis and chi-square test of salt-tolerant phenotype of F2 population showed that the salt tolerance of the combination 01 was likely controled by major gene. A wheat specific SSR marker Xgwm304 was decided to link with salt-tolerant locus of wheat variety Shanrong No.3. 【Conclusion】The genetic distance between Xgwm304 and the critical gene is 24.41 cM (centMorgan). The major salt tolerance gene in wheat variety Shanrong No.3 has been located on 5AS of wheat chromosome.
    Study on Transformation of Wheat with SacB Gene From Bacillus subtilis
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    Scientia Agricultura Sinica. 2006, 39(02):  231-236 . 
    Abstract ( 1767 )   PDF (520KB) ( 1841 )   Save
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    【Objective】SacB gene from Bacillus subtilis will be transferred into wheat cultivars or breeding lines 02-371, 02-207, Zhengmai 9023 and Dongnong 7742 for improving their tolerance to drought stress. 【Method】Using wheat immature embryo calli as explants, SacB gene was transferred into four wheat cultivars by Agrobacterium-mediated transformation. Transformed plants were detected by PCR and Southern blotting. 【Result】 PCR and Southern blotting analysis showed that the SacB gene has been integrated into wheat genome. One or two copies of integrated transgene were in transgenic plants. The transformation frequencies of Line 02-371, Line 02-207, Zhengmai 9023 and Dongnong 7742 were 0.88%, 1.48%, 1.04%, and 1.23%, respectively. RT-PCR analysis showed that the SacB gene was expressed in some transgenic plants, of which the tolerance to drought stress was significantly improved. 【Conclusion】 SacB gene from Bacillus subtilis can improve the tolerance of transgenic wheat plants to drought stress.
    The Genetic Diversity Variation Revealed by SSR Markers in the Tropical Maize Population Pob32 After 5 Cycles of Mass Selection
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    Scientia Agricultura Sinica. 2006, 39(02):  237-245 . 
    Abstract ( 1702 )   PDF (268KB) ( 1622 )   Save
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    【Objective】The biparental mass selection was used to improve the tropical population Pop. 32 for 5 cycles for photoperiod sensitivity in Sichuan Povince, China.【Method】Phenotype analysis and SSR molecular markers were used in this research.【Result】Results showeds that the traits of flowering were significantly improved after 5 cycles of mass selection. The phenotypic variation coefficients of most of the traits decreased with the advances of generation of selection. With the 40 pairs of SSR markers used, a high level of genetic diversity was in C0 population, a total of 418 alleles were detected in the populations. Some 88.5% of the genetic diversity were estimated intra-populations and 11.5% were estimated inter-populations. The inter-population's genetic diversity was much more than the intra-population's, and the genetic diversity within populations declined with the advances of generation of the selection. The number of polymorphic loci of per population and the ratio of polymorphic loci were also declined as selection. The genotypic numbers of Pop32.C0 was 418, which was the most but the frequency was dispersed. The genotype of Pop32 C4 and Pop32.C5 were small and the frequencies were concentrated. 【Conclusion】The results suggest that the genetic variation declined slowly is possible due to the continuous artificially selection for the early silking and the genetic drift induced by selection intensity or smaller effective population size.
    Analysis of Genetic Diversity and Genetic Basis of Chinese Rapeseed Cultivars (Brassica napus L.) by Sequence-Related Amplified Polymorphism Markers
    YanCheng Wen,,,,
    Scientia Agricultura Sinica. 2006, 39(02):  246-256 . 
    Abstract ( 1841 )   PDF (578KB) ( 2580 )   Save
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    【Objective】In order to investigate the Genetic diversity and genetic basis of rapeseed (B. napus L.) in China, 【Method】Total 130 accessions developed in different years since 1949 were analyzed using SRAP (sequence-related amplified polymorphism) markers. 【Result】A total of 509 amplified fragments and 123 polymorphic fragments were detected by applying 25 SRAP primer combinations. The polymorphic fragment percentage was 24%. The number of amplified fragments and polymorphic fragments per primer combination were 20.4 and 4.9, respectively. 130 B. napus accessions were divided into four groups of A, B, C and D at genetic distance of 0.12. About 78.5% of total accessions were classified into group C. Group C could also be divided into I, II, III, IV and V sub-groups at genetic distance of 0.10. About 58.5% of total accessions were classified into sub-group I, indicating the genetic diversity of 58.5% accessions of total was poor. The results demonstrated that the genetic basis of B. napus L. accessions released before 1980 was the narrowest while those released in 1980s reached the widest. In 1990s, the genetic distances of B. napus L. accessions declined again. The genetic basis of B. napus L. accessions narrowed further after 2000. Though the difference of mean genetic distance between accessions bred in 1990s and after 2000 did not reach a significant level, the difference in mean genetic distance in different periods was at 0.01 or 0.05 significant level. The difference in mean genetic distance between accessions bred in China and introduced from abroad reached a significant level at 0.01. 【Conclusion】All these results showed that SRAP markers were economic, effective, and reliable.
    TILLAGE & CULTIVATION·PHYSIOLOGY & ECOLOGY
    Effects of Cultivation Methods on Grain-Filling and Chalky Grains of Upland and Paddy Rice
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    Scientia Agricultura Sinica. 2006, 39(02):  257-264 . 
    Abstract ( 2167 )   PDF (255KB) ( 1957 )   Save
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    【Objective】The effects of cultivation methods on grainfilling and chalky grains were studied with upland rice of Zhonghan 3 (japonica) and paddy rice of Wuxiangjing 99-8 (japonica) as materials. 【Method】Three different cultivation methods of moist cultivation (MC, control), plastic film mulching cultivation (PFMC) and bare cultivation (BC) were set up. 【Result】The results showed that, compared with the MC, the grain yield was significantly lower under PFMC for upland rice, but there was no significant difference in grain yield between PFMC and MC for paddy rice. BC significantly reduced grain yield for both upland and paddy rice. Superior and inferior grains of upland rice had higher relatively grain-filling potential (R0/W), higher maximum grain-filling rate (Gmax), higher mean grain-filling rate (G) and higher grain weight, shorter time reaching the maximum grain-filling rate (Tmax) and lower percentage of chalky grains under dry cultivation (PFMC and BC) than under MC. Paddy rice showed opposite trends in R0/W and Tmax under dry cultivation. There was no significant difference in the percentage of chalky grains between PFMC and MC for paddy rice, whereas BC significantly reduced the percentage of chalky grains. The chalkiness was significantly decreased under dry cultivation for both upland and paddy rice. The percentage of chalky grains was very significantly and significantly negatively correlated with Gmax and G. 【Conclusion】The results suggested that dry cultivation could increase grain-filling rate and improve the appearance quality for both upland and paddy rice.
    Effect of Cotton Physiological Age on the Fiber Thickening Development and Fiber Strength Formation
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    Scientia Agricultura Sinica. 2006, 39(02):  265-273 . 
    Abstract ( 1463 )   PDF (540KB) ( 1707 )   Save
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    【Objective】Effects of physiological age of cotton plant on the physiological mechanism of fiber thickening development and fiber strength were studied.【Method】 By setting different seeding times, puting the fiber thickening development process of boll which situated in the different positions of cotton plant under the same temperature conditions, mean daily temperature for summer boll, early autumn boll and late autumn boll within boll age of 25 to 50 days were 22.0℃,19.4℃ and 15.3℃ accordingly.【Result】The results of 2-year experiment showed that: there were double effect of temperature and physiological age of cotton plant on fiber thickening development and fiber strength formation, the physiological age of cotton plant was the principal factor and there were evidently effects on fiber thickening development of summer boll for the top fruiting branches and early autumn boll for the lower fruiting branches, boll weight and lint percent and fiber strength in these portion were lower than the others. Low temperature in fiber thickening development process was the principal factor that affected fiber thickening development and fiber strength of late autumn boll. Under this testing condition of which the mean daily temperature for late autumn boll was 15.3℃, the fiber sucrose synthetase activity was evidently fall, and the β-1, 3-glucanase activity moved up, the cellulose accumulation quantity and accumulation rate reduced obviously, boll weight was smaller than 2 g and fiber strength was less than 20 CN·tex-1. 【Conclusion】Effect of the cotton physiological age on the fiber strength enhanced more and more among summer, early autumn and late autumn bolls.
    Design and Implementation of a Dynamic Knowledge Model for Suitable Cultivars and Sowing Time of Maize
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    Scientia Agricultura Sinica. 2006, 39(02):  274-280 . 
    Abstract ( 2393 )   PDF (247KB) ( 2218 )   Save
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    【Objective】This study was designed to develop a spatial and dynamic knowledge model for suitable cultivars and sowing time of maize. 【Method】Applying the knowledge engineering method and mathematical modeling technique, a dynamic knowledge model for suitable cultivars in maize was established by quantitatively calculating the relationship of the cultivar characteristics to environmental factors and production requirement. The knowledge model for suitable sowing time is based on the synchronization between the maize growing process and the suitable season. 【Result】Cases were studied on the suitable cultivars selection model with data sets of eight typical cultivars and three different eco-sites, such as Beijing, Ji'nan, Shenyang, and on suitable sowing time decision model with data sets of a typical cultivar and three different eco-sites as well. 【Conclusion】 The result indicated a good performance of the knowledge model in decision-making and wide applicability.
    Research Progress and Prospect of Digital Farming Techniques
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    Scientia Agricultura Sinica. 2006, 39(02):  281-288 . 
    Abstract ( 2394 )   PDF (304KB) ( 2414 )   Save
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    The objective of this paper is to introduce the recent research progress and future prospect of digital farming techniques. Digital farming is to develop the key techniques and application systems for acquisition, analysis, management and utilization of information in crop production system by comprehensively using digital techniques and realizing digital expression and integration of information flow in crop production system. In recent years, thorough and systematic research work on the key techniques and application systems of digital farming have been carried out in Hi-tech Key Laboratory of Information Agriculture of Jiangsu Province, and remarkable advances have been achieved in the areas of crop growth simulation model, crop management knowledge model, non-destructive crop growth monitoring, spatial information management in crop production system, and decision support system for digital crop management. The future prospect of digital farming is directed toward informationization and digitalization of crop production components and processes, by comprehensive development of the key techniques for information management of agricultural resources, automatic monitoring of crop conditions, digital simulation of crop processes, visual design of crop plants, quantitative expression of farming knowledge, and precision control of production management. Further, the integrative software and hardware systems on the basis of digital farming techniques will be constructed for realizing digitalization, precision, visualization and network service in monitoring, prediction, design, management and control of crop production system. Digitalization of farming system will facilitate the informationization and modernization of agricultural industry.
    Advance in Genetic Improvement of Water Use Efficiency in Crops
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    Scientia Agricultura Sinica. 2006, 39(02):  289-294 . 
    Abstract ( 1734 )   PDF (210KB) ( 2377 )   Save
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    Advance in the difference of water use efficiency (WUE) among different plant species and varieties, evolution of WUE, gene localization and molecular markers of WUE, gene cloning and transgene of WUE, genetic improvement of WUE and biological water saving, was introduced in this paper. These information show that genetic improvement of WUE has attracted more attention and will play an important role in biological water saving and water saving agriculture.
    PLANT PROTECTION
    Analysis on the Rust Resistance Genes of a New Wheat Germplasm YW243 by Molecular Markers
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    Scientia Agricultura Sinica. 2006, 39(02):  295-299 . 
    Abstract ( 2530 )   PDF (328KB) ( 1913 )   Save
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    【Objective】 A new wheat line YW243 is a recently developed new germplasm with multi-resistance to wheat stripe rust, stem rust, leaf rust, wheat yellow dwarf and powdery mildew. In this study, the gene composition of the stripe and stem rust resistance of YW243 was analyzed. In order to clarify the sources of the rust resistance genes of YW243, YW243 and its parents, such as Fengkang 8, Fengkang 13, Shan 7859, Suwon 11 and Heine Hvede, were analyzed by the molecular markers of the resistance genes . 【Method】 The composition and the sources of the stripe and stem rust resistance genes of YW243 were analyzed by using PCR markers of Yr9, YrX, Yr2, Yr1, Sr31 and SDS-PAGE. 【Result】 YW243 possessed at least four stripe rust resistance genes of Yr1, Yr2, Yr9 and YrX, one stem rust resistance gene Sr31. Shan 7859 and Fengkang13 are the sources of Yr1 in YW243, Shan7859, Fengkang 8 and Fengkang13 are the sources of Yr2 in YW243, Fengkang 13 is the source of YrX of YW243. Fengkang 8 and Shan 7859 are the sources of Yr9 and Sr31 of YW243. 【Conclusion】YW243 is a good resistance germplasm for wheat breeding in the future.
    Biological Characteristics of Allantophomoides carotae
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    Scientia Agricultura Sinica. 2006, 39(02):  300-305 . 
    Abstract ( 1766 )   PDF (346KB) ( 1400 )   Save
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    【Objective】 Allantophomoides carotae is the firstly-reported new strain by the author in China. It can cause the Carrot Spotted Withering Disease, thus makes great damage in the course of the production process. 【Method】The effects of temperature, pH, illumination and the sources of nitrogen and carbon on the growth of hypha, the emergence and germination of conidiospore of Allantophomoides carotae were studied.【Result】 The most suitable range of temperature is 10-30℃ and the optimum temperature is 25℃ for hypha growth, the lethal temperature is 45℃(within 30 min) or 50℃(within 10 min) for conidiospore and 65℃(within 30 min) for hypha. Within the pH range of 4-12, the hypha could grow and produce conidiospore, and the conidiospore could germinate. The optimum pH is 8-10 for hypha growth and 7-9 for conidiospore germination; The hypha could not grow on the culture medium which nitrogen source comes from urea and asparagines, but it could grow fast and produce more conidiospore on the culture medium which carbon source comes from maltose, glucose and lactose, and nitrogen source come from glycine, histidiane and peptone. The effect of illumination on Allantophomoides carotae was insignificance to the growth hypha and the emergence and germination of conidiospore. 【Conclusion】The study of this article tentatively made a research of the biological characteristics of this pathogenic bacteria. It provides a theoretical basis for the prevention and control of this disease.
    Sampling Survey and Identification of Races of Soybean Cyst Nematode (Heterodera glycines Ichinohe) in Huang-Huai Valleys
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    Scientia Agricultura Sinica. 2006, 39(02):  306-312 . 
    Abstract ( 1899 )   PDF (502KB) ( 1364 )   Save
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    【Objective】In order to investigate patterns and distribution of races of Soybean cyst nematode (SCN Heterodera glycines Ichinohe) 【Method】A total of 38 sites in Huang-Huai valleys were sampled and identified for the distribution of soybean cyst nematode races during 2001- 2003. A map of race distribution was constructed according to the data from this experiment and literature cited. 【Results】Three areas mainly infested with Race 1 were identified, i.e. the area south-east to Jinan in Shangdong Province, the area of northern Henan Province and its border region to south of Hebei Province, and the area of Luohe, Zhoukou of Henan Province and Fuyang of Anhui Province. Race 4 was predominant in Shanxi Province, Beijing and the adjacent area of Henan, Shandong and Anhui Provinces, and the delta of Huanghe River in Shandong Province. Race 2 was mainly in Liaocheng, Dezhou of Shangdong province and Shijiazhuang of Hebei province, and Jiaozuo and Huojia of Henan Province. Race 7 distributed in the west part of Jiaodong Peninsula of Shandong Province and Kaifeng, Huaxian, Wenxian of Henan Province. Race 5 was found and scattered in Hebei and Henan Province. Race 9 was found in Shangqiu of Henan Province, which was reported the first time in China. 【Conclusion】From the above, Race 1 and Race 4 were the two predominant races in Huang-Huai valleys, which should be focused on for developing resistant cultivars. There might exist other races in an area with some predominant races. The race change in the past decade was not obvious, therefore, the results are meaningful to the present breeding for resistance to SCN in Huang-Huai valleys.
    Characterization and Identification on the Pathogen of Potato Scab in China
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    Scientia Agricultura Sinica. 2006, 39(02):  313-318 . 
    Abstract ( 1384 )   PDF (400KB) ( 1962 )   Save
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    【Objective】The pathogens causing potato scab in ten provinces in China were identified.【Method】 The scab-related strains were analyzed according to the biological characteristics and the 16S rDNA sequences. 【Result】The Streptomyces scabies strains from China have the same 16S rDNA sequences to standard S. scabies strain ATCC 49173 from America. But their biological characteristics are different. Chinese Streptomyces scabies strains can not use D-mannitol as single carbon sources, unsensitive to penicillin G (10 IU·ml-1) and produce the H2S. The 16S rDNA sequences of Chinese S. acidiscabies strains are similar to standard S. acidiscabies one ATCC 49003(99.8%). It can use raffinose as single carbon source, sensitive to phenol (0.1%) and crystal violet (0.5 ?g ml-1), and can not produce the H2S. A novel scab-related Streptomyces specie was found in this work.【Conclusion】The results showed that the pathogens causing potato scab in China were belong to Streptomyces scabies, S. acidiscabies and a novel Streptomyces species respectively.
    The Monoclonal Antibodies to the English Wheat Aphid, Sitobion avenae (Fabricius), and Their Characteristics
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    Scientia Agricultura Sinica. 2006, 39(02):  319-323 . 
    Abstract ( 1581 )   PDF (254KB) ( 1242 )   Save
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    【Objective】The English grain aphid, Sitobion avenae (Fabricius), is one of main wheat pests all over the world. It is very important to fully exert the natural control of predatory natural enemies in wheat fields in order to control the wheat aphid. 【Method】Hybridoma technolgy was used to develope monoclonal antibodies(McAbs) to the English grain aphid. The classes and subclasses of McAbs were determined by a double-antibody sandwich ELISA. Antibody specificity was tested using an indirect ELISA. SDS-PAGE and Western blot analysis were used to determine the proteins reacted with the antibodies.【Results】Two highly specific monoclonal antibodies were developed, namely EGA-1E8 and EGA-4H11, respectively. McAb EGA-1E8 was IgM subclass while McAb EGA-4H11 belonged to IgG2b subclass. McAb EGA-4H11 reacted with a single peptide of molecular weight 54.2 kD. The specificity test showed that both McAbs had no cross-reaction with other insects and spiders in wheat fields. 【Conclusion】The successful development of S. avenae McAbs may establish an essential tool for further study on the predatory natural enemies of the wheat aphid in wheat fields.
    SOIL & FERTILIZER·WATER-SAVING IRRIGATION
    Changes of Organic Carbon and Nutrient Contents in Highly Productive Paddy Soils in Yujiang County of Jiangxi Province
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    Scientia Agricultura Sinica. 2006, 39(02):  324-330 . 
    Abstract ( 2846 )   PDF (381KB) ( 1806 )   Save
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    【Objective】Studies on changes in organic carbon and nutrient contents of the highly productive paddy soils would be scientifically beneficial to the directional management and sustainable utilization of paddy soils. 【Method】The contents of organic carbon and nutrients and their changes in the last over 20 years in the highly productive paddy soils as related to the environmental significance were investigated by field sampling and comparison with the corresponding values in the Second Soil Survey in Yujiang County of Jinagxi Province. 【Result】Results showed that 0-10 cm depth highly productive paddy soils in Yujiang County of Jiangxi Province contained organic carbon content of (20.2±3.88) g·kg-1, total N (2.09±0.55) g·kg-1, available phosphorus (42.7±32.7) mg·kg-1, respectively, all were at the very rich level. In the last over 20 years, the organic carbon pool of the highly productive paddy soils remained a stable state, total N and available P increased significantly, while available K changed little. The amount and percentage of P immobilized in 0-10 cm highly productive paddy soils were (142.7±41.1) mg·kg-1 and (36.2±10.4)% and of added P CEC was (7.93±1.32) cmol·kg-1, being not higher than the mean value of paddy soils and that in upland red soils. It indicated that fertilizer P in highly productive paddy soils would be a high mobility and easily moved to water, being a main source of nutrient causing eutrophication. 【Conclusion】For a long-term rice cultivation and fertilization, the highly productive paddy soils were very rich levels of organic matter and available P, and a steady state of organic carbon pool, while amount of P immobilized was not high. Because of a weak K-fixing capacity, the available K content was not rich in highly productive paddy soils, suggesting that attention should be paid to the balance and increase of soil K pool.
    Research on Successional Regulation of Soil Environment After Reclamation in the Manas River Valley
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    Scientia Agricultura Sinica. 2006, 39(02):  331-336 . 
    Abstract ( 1722 )   PDF (347KB) ( 1249 )   Save
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    【Objective and Method】This research taking the alluvial-fan oasis in Manas river as an example, through the fixed position experiments, the trend estimation model of principal component analysis and so on, the succession of plants and soil characteristics of field in the bottom of alluvial-fan oases were investigated and analyzed.【Result】With the increase of years of reclamation the salt-loving, perennial plants were substituted by annual plants and then entered a stable stage after 6-8 years. Total salt content decreased gradually and then increased, which reached the lowest after reclamation for 9.46 years. The soil nutrient showed the contrary to sail. The comprehensive quality of soil was a positive development in the first 10 years and then turned to degeneration. Through the trend estimation model of principal components analysis, farmland attains to the best performance in quality till 10 years. 【Conclusion】Synthetically analysis the various index of the soil quantity, so 10-15 years could be used as early-warming time to reflect the change of soil quality.
    Degradation of Antibiotics and Passivation of Heavy Metals During Thermophilic Composting Process
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    Scientia Agricultura Sinica. 2006, 39(02):  337-343 . 
    Abstract ( 3281 )   PDF (423KB) ( 3380 )   Save
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    【Objective】The problem that there are various antibiotic medicines and heavy metal elements in excrements of livestock and poultry have been concerned on the farm utilization extensively. The techniques for the antibiotics degradation and heavy metals passivation were studied in the experiments.【Method】As composting is a new alternative bioremediation technology for treatment of organic pollutants and heavy metals, two experiments were conducted to evaluate the effect of using thermophilic composting to break down the content of tetracyclines(TTC, OTC, CTC) and H2O extractible of heavy metals(Cu, Zn, Cr, As). 【Results】The result of TCs degradation test indicated that the degradation of TTC, OTC and CTC using P+S and C+S in all treatments was effective, but in comparision, the addition of BM bacterium for TCs degradation in treatment was more effective, and its biodegradation rate was higher than that of P+S+TCs and C+S+TCs treatment. The biodegradation rate of OTC was the lowest in all treatments, and the rate of C+S+OTC treatment was 40.23%. The order of the three TCs biodegradation rate was TTC> CTC> OTC. The air-slaked coal has a passivation effect on the heavy metal elements in excrements of livestock and poultry. The result of heavy metal passivation test showed that the effect of addition of air-slaked coal to H2O extractible content of heavy metals, such as Cu, Zn, Cr and As, were obvious, the passivation effect of ari-slaked coal treatment was better than that of control. The H2O extractible content of heavy metals of Cu, Zn, Cr and As, after composting of pig manure, reduced by 6.17%, 6.40%, 4.17% and 1.83%, respectively, meanwhile, the H2O extractible contents after composting of chicken manure reduced by 7.07%, 5.69%, 5.50% and 2.07%, respectively. 【Conclusion】With the different thermophilic composting conditions, tetracyclines antibioticses can be degraded, and the addition of foreign beneficial bacterium can reduce residues in antibiotic medicine. Thermophilic composting also can lower the effects of heavy metals on plants. Air-slaked coal has passivation function on extractible heavy metals.
    Phylogenetic Diversity of Rhizobia Isolated from the Root Nodules of Peanut (Arachis hypogaea) Grown in Hebei
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    Scientia Agricultura Sinica. 2006, 39(02):  344-352 . 
    Abstract ( 2248 )   PDF (653KB) ( 1773 )   Save
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    【Objective】 We hope to understand the diverse state of peanut rhizobia in northern part of China. 【Method】 Fifty eight rhizobial strains isolated from root nodules of peanut plants grown at different sites in Hebei Province were analyzed and compared with the reference strains of the species of Rhizobium, Agrobacterium, Sinorhizobium, Mesorhizobium and Bradyrhizobium by 16S rDNA PCR-RFLP, 16S-23S IGS PCR-RFLP and 16S rRNA gene sequencing. 【Results】 The results showed that thirty eight strains belonged Bradyrhizobium related to Bradyrhizobium japonicum and Bradyrhizobium liaoningense. 【Conclusion】 It demonstrates that peanut plants nodulate mainly with Bradyrhizobium strains in Hebei, similar to the previous reports with rhizobia from peanut plants grown in other regions of China. However, the existence of six fast-growing rhizobial strains related to R. yanglingense, R. mongolense, and R. gallicum and of ten moderately slow-growing strains indicate that peanut plants attract diverse rhizobia in Hebei Province.
    HORTICULTURE
    Simulation of Dry Matter Partitioning, Yield Formation and Fruit Harvest Date of Greenhouse Muskmelon
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    Scientia Agricultura Sinica. 2006, 39(02):  353-360 . 
    Abstract ( 2025 )   PDF (375KB) ( 1646 )   Save
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    【Objective】 The aim of the study was to develop a simulation model to predict the yield and harvest date of greenhouse muskmelon for the optimization of climate control and crop management for greenhouse muskmelon production. 【Method】Based on the relationships between partitioning index and the accumulated product of thermal effectiveness and photosynthetically active radiation (TEP), a dry matter partitioning,yield formation and harvest date simulation model for greenhouse muskmelon was developed. Experiments with different sowing dates and substrates were carried out in Shanghai and Nanjing to collect data to develop and validate the model. 【Result】The results showed that for shoot dry weight, root dry weight, stem dry weight, leaf dry weight and fruit dry weight, the coefficient of determination R2 between the simulated and the measured value based on the 1:1 line was 0.99, 0.65, 0.97, 0.98, 0.98, respectively; and the relative prediction error (RSE) was 0.88%, 70.21%, 7.44%, 9.33%, 5.28%, respectively. The R2 and RSE between the simulated and the measured fresh weight of muskmelon based on the 1:1 line was 0.94 and 8.13%, respectively. The R2 and RSE between the simulated and the measured diameter of muskmelon fruit based on the 1:1 line were 0.95 and 9.23%, respectively. The prediction error for harvest date was in 1 day. 【Conclusion】From the results mentioned above, it can be concluded that the model developed in this study not only can give satisfactory prediction of dry matter partitioning, yield and harvest date of greenhouse muskmelon, but also is user-friendly.
    Characteristics of N, P, and K Nutrition in Different Yield Level Apple Orchards
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    Scientia Agricultura Sinica. 2006, 39(02):  361-367 . 
    Abstract ( 2281 )   PDF (319KB) ( 1784 )   Save
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    【Objective】In order to get the information about the characteristics of N, P, K nutrition in different yield level apple orchards. 【Method】 The orchards with ten-year-old apple trees (M. domestica Borkh. cv. Red Fuji/M. hupenensis Rhed) were divided into four types, soil and plant samples were collected and determined at certain time from 1997 to 2000, fertilizer treatments were also conducted in different type orchards. 【Result】The results showed that soil alkaline hydrolyzable N, available P and K concentration had an increasing tendency as yield level increased, indicating the important effect of soil fertility on yield. But the three index value changed much and had low correlation index with yield at the same yield level. At high yield level orchards leaf total N and P, fruit total N were relatively high but leaf total K and fruit total P were relatively low, leaf total K was mostly influenced by yield, and decreased with yield increased. The effect of fertilizer on yield was changed with the change of yield level. Application of P did not increase yield at all four yield level orchards, but as K was concerned, and it was contrary. Application of N increased yield at middle and low yield level orchard. 【Conclusion】Fertilizer application amounts to apple trees should base on not only the yield but also the soil available nutrients. The estimation of K level in apple trees should base on not only the leaf K concentration but also the effect of yield on K absorption and distribution.
    Analysis of the Factors Affecting Callus Induction and Plant Regeneration of Zoysia japonica Steud. from Mature Seed
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    Scientia Agricultura Sinica. 2006, 39(02):  368-374 . 
    Abstract ( 2608 )   PDF (282KB) ( 1568 )   Save
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    【Objective】In order to optimize tissue culture system of Japanese lawngrass (Zoysia japonica Steud.), and to improve plantlet regeneration rate and to establish high efficient plant regeneration from seed-derived callus, mature caryopses were used as explants. 【Method】The effect of hormone, basical media, cultivation condition, L-proline, Cu2+ on callus induction, maintenance and plantlet regeneration were investigated. 【Result】The results are as follows: (1) The addition of 500 mg·L-1 L-proline to the media was beneficial to callus induction. The addition of BA to the media was disadvantageous to callus induction. Lower concentration NAA increased callus induction rate. The best media for callus induction was ND+2,4-D 3.0 mg·L-1+NAA 0.2 mg·L-1 and the ratio of callus induction was 57.3%. (2) The best media for callus subculture was MSD+ 2,4-D 1.0 mg·L-1. (3) The best differentiation media was MSD+NAA 0.3 mg·L-1+ KT 0.5 mg·L-1+ BA 0.05 mg·L-1 and the ratio of differentiation was 36.7%.【Conclusion】The in vitro system of Japanese lawngrass was optimized and the main factors affecting seed-derived callus induction and regeneration were primarily traced.
    Optimization and Establishment of Quantitatively Competitive PCR System for the Detection of Alicyclobacillus acidoterrestris
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    Scientia Agricultura Sinica. 2006, 39(02):  375-381 . 
    Abstract ( 2867 )   PDF (462KB) ( 1854 )   Save
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    【Objective】To study the detective method of Alicyclobacillus acidoterrestris in apple juice concentrate (AJC) by quantitatively competitive polymerase chain reaction (QC-PCR) system. 【Method】 The QC-PCR system for detection of Alicyclobacillus acidoterrestris was established through the primer design, PCR amplification, and reclaim of gel purification reagent box to construct and obtain the competitive template which was used as quantitative internal standards. 【Result】 The QC-PCR system was optimized and established in this study, and the detective sensitivity of the target template had gotten better from 5×104 to 50 molecules /PCR system. As a result of this, 5×102 target template molecules /PCR system was detected when the two templates co-amplified, and 5×103 cfu / PCR system of Alicyclobacillus acidoterrestris in AJC was detected. The detective time (4 h to 5 h) is remarkably shortened from traditional method(4 d or 5 d)using plate culture counting. 【Conclusion】 The method in this study is better than others in efficiency and specificity, which can be a reference for competitive template construction of microbe PCR and constructive methodology of QC-PCR. It has potential to be applied in AJC commercial production process for the rapid detection of Alicyclobacillus acidoterrestris.
    Study on the Inhibitory Effects of Natural Sweetner Mogrosides on Radical and Lipid Peroxidation
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    Scientia Agricultura Sinica. 2006, 39(02):  382-388 . 
    Abstract ( 2455 )   PDF (303KB) ( 2364 )   Save
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    【Objective】The antioxidant activity of mogroside extract (MG) and mogroside V in vitro was studied.【Method】D-deoxyribose method, reagent box method and spectrophotometry method were used to determine the inhibitory effect on radical, hemolysis of red blood cells and lipid peroxidation.【Result】(1) It was found that mogroside extract could scavenge different radicals effectively, protect liver tissue in rat from peroxidation induced by Fe2+ or H2O2 and inhibit the hemolysis of red blood cells. (2) The scavenging .OH effect of mogroside V was the same as mogroside extract, but its scavenging O2- effect was better than that of MG.【Conclusion】It is concluded that mogroside extract has antioxidant effects and mogroside V may be the main antioxidant components of the extract.
    ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT
    Study on Genetic Diversity and Classification of the Yak
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    Scientia Agricultura Sinica. 2006, 39(02):  389-397 . 
    Abstract ( 1320 )   PDF (310KB) ( 1881 )   Save
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    【Objective】The genetic diversity and classification of partial chinese yak breeds including Maiwa yak (two populations), Jiulong yak, Datong yak, and Tianzhu white yak were studied in order to indicate the degree of genetic diversity and provide a more reasonable type division. 【Method】 The genetic diversity of nine microsatellite sites in above five yak populations was studied by means of PCR, and the alleles frequency, polymorphism information content (PIC), heterozygosity (H) and effective number of alleles(Ne) in different yak populations computed by means of statistics method. At the same time, the cluster of these yaks has also been researched. 【Result】 (1) The nine microsatellite sites analyzed were polymorphic in these yak populations and all of them were highly polymorphic sites. The average numbers of alleles and polymorphism information content (PIC) in each site were 6.8 (ranged from 5 to 9) and 0.6534 (from 0.5037 to 0.7351) respectively. The difference of average PIC among these populations was not significant. The average heterozygosity in all populations was 0.6625, which varied from the highest in Ruoergai population of Maiwa yak (0.6883) to the lowest in Jiulong yak (0.6317). Accordingly, the average effective number of alleles was 3.2680(ranged from 3.189 to 3.4478), with the lowest for Jiulong yak. These results indicated that there was a good compatibility between the parameters including allele frequencies, PIC, heterozygosity(H) and effective number of alleles(Ne) in different yak populations. It also showed that there was rich in genetic polymorphisms of microsatellite sites within a breed and between breeds of the yak. (2) All calculated parameters showed that there was a significant difference between Jiulong yak and other yak populations. The same conclusion could be also taken from the results of genetic distance and cluster analysis. The greatest genetic distance (1.506) occurred between Jiulong yak and Maiwa yak of Hongyuan, while the lowest (1.062) occurred between two populations of Maiwa yak. These five yak populations could be classified as two groups by clustering analysis, i.e., Jiulong yak was a separate group, the other four populations were in another. The two populations of Maiwa yak were clustered as one at first, then the Datong Yak and the Tianzhu white yak. This result was in accordance with the fact of their distribution, ecological conditions, the breeding history and differentiation of different yak populations, and it was also as same as classification result of Cai Li.【Conclusion】(1) There was rich in genetic polymorphisms of microsatellite sites within a breed and between breeds of the chinese yaks. (2) This cluster result was in accordance with the classification of Cai Li. So, it was reasonable to classified Chinese yaks into two types including Qinghai-Tibetan Plateau yak and Henduan mountain Alpine yak.
    Microsatellite Analysis of Genetic Diversity and Phylogenetic Relationship of Eight Donkey Breeds in China
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    Scientia Agricultura Sinica. 2006, 39(02):  398-406 . 
    Abstract ( 2403 )   PDF (374KB) ( 1923 )   Save
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    【Objective】To reveal the genetic diversity and phylogenetic relationship of china donkey breeds, 【Method】 the genetic polymorphisms of 24 microsatellites in 8 china large and middle-sized donkeys were studied by means of PCR polyacrylamide gel electrophoresis and silver staining. Number of alleles, average effective number of alleles (E) and average rates of homozygote of each breeds were counted. According to allele frequencies of 24 microsatellites, polymorphism information content(PIC),mean heterozygosity (h) and genetic distances (DA) were calculated for each breeds, By using the Neighbour-joinig method of Dispan software, the polymorphic trees were constructed based on genetic distances. The systematic relation was analyzed as well. 【Result】The results showed that NVHEQ18 is medium polymorphic and the other 23 of 24 microsatellite loci were highly polymorphic, The average PIC (0.6940), h (0.7119) and E (2.9) of the eight donkey breed population were all higher ,which showed the gene polymorphisms and genetic diversity were higher. Guanzhong donkey、Jinnan donkey、Guangling donkey and Dezhou donkey of large breeds and Qingyang donkey of middle-sized clustered in one group and Biyang donkey、Huaiyang donkey and Jiami donkey of middle-sized clustered in another groups. The phylogenetic relationship between different breeds were in accordance with their breeding history and distribution. 【Conclusion】The 24 microsatellite loci were effective markers for analysis of genetic relationship among donkey breeds.
    Effects of Bio-Treatments on Desilicification for Improving Rice Straw Degradability
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    Scientia Agricultura Sinica. 2006, 39(02):  406-411 . 
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    【Objective & method】The focused effects of bio-treatments on desilicification and delignification for improving rice straw degradability were studied by comparing two bio-products of AgroGreen? (AG) and Yeast Extract? (YE), two microbial pre-culture of Agaricus blazei (A.b) and Volvariella volvacea (V.v). 【Results】Results showed that AG and YE were proved no effect on desilicification. The concentration of AG used indicated an inhibition to the growing of rumen microorganisms. However, YE enhanced straw degradability (P<0.05) by pre-treatment but lowed the degradation of straw by directly adding to nurturing ruminal microbe. By pre-culture of A.b and V.v, this increased Si-extractability by about 54.8% and 58.9%, reduced total phenolic components by about 86.4% and 79.7%, respectively. Among phenolic monomers, the proportion of flavonol was increased from 49% to 73% and 80%, but the proportion of rest was reduced from 39% to 18% and 12% for benzoic acids, and from 12% to 9% and 8% for hydroxycinnamic acids, respectively. 【Conclusion】AG and YE were proved no effect on desilicification, and the pre-culture of A.b and V.v had improved the degradation quality of treated rice straw.
    Pathogenicity of H5N1 Influenza Virus for Ducks
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    Scientia Agricultura Sinica. 2006, 39(02):  412-417 . 
    Abstract ( 2464 )   PDF (298KB) ( 2222 )   Save
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    The ducks are considered to be a natural reservoir for influenza viruses. Neither shows any clinical symptoms nor mortality when ducks infected with influenza virus. In order to assess the pathogenesis of the influenza A virus A/Goose/HLJ/QFY/03 (H5N1) isolated from a diseased geese farm, the SPF chickens and ducks were challenged by natural route, respectively. Challenge experiments demonstrated that the isolate was highly pathogenic both to chickens (IVPI=3) and ducks where it produced 75% mortality. Depression and marked nerologic dysfunction were common clinical manifestations of disease. Gross lesions included liver and splenomegly, hemorrhages; lung with severe acute congestion and hemorrhages; diffused enteric mucosa hemorrhages in alimentary tract. Histologic lesions were observed in multiple parenchymal organs and were characterized by congestion, hemorrhage, degeneration to necrosis or heterophilis infliltration. High titers of viruses were isolated from tracheal and cloacal swabs as well as multiple organs by 2-4 DPI (days post infection), and the viruses were confined only to pancreas after 7 DPI. This is the first confirmed H5N1virus isolated from domestic poultry that are lethal to ducks.
    Pharmacokinetics and Residues of Danofloxacin Mesylate in Goldfish (Carassius auratus Linnaeus)
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    Scientia Agricultura Sinica. 2006, 39(02):  418-424 . 
    Abstract ( 2844 )   PDF (332KB) ( 1756 )   Save
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    【Objective and method】The plasma pharmacokinetics and tissue residues of danofloxacin mesylate (DFM) were investigated in goldfish, under experimental field conditions at 20℃ after single oral gavage administration(10 mg·kg-1 b.w). The danofloxacin concentrations in plasma and tissues samples were determined by using reversed-phase high performance liquid chromatography(RP-HPLC) after liquid-liquid extraction. Ofloxacin hydrochloride was selected as internal standard. Plasma concentration-time data of DFM were best fitted using a two-compartmental open model, with absorption, distribution and elimination half-life of 0.63, 4.96 and 47.79 h, respectively. The maximal plasma concentration was 3.23 μg·ml-1, peaking at 2.73 h after dosing. Area under the plasma drug concentration-time curve from 0 to ∞ was 154 μg·h·ml-1. The mean residence time (MRT) was 58.56 h using non-compartmental analysis based on statistical moment theory. 【Results】The results indicated that the concentration of DFM in kidney, liver, plasma, muscle and skin was significantly higher than that in plasma , with elimination half-life of 33, 44, 48, 51 and 177 h, respectively. To compare with other tissues, the elimination of DFM in skin was slowest, which behaved as a reservoir tissues in goldfish. It is proposed that withdrawl period should be not less than 23 days after single oral administration (10 mg·kg-1 bw) of DMF to goldfish at 20℃, according to the maximum residue limit(MRL) of 100 mg·kg-1 in skin.
    RESEARCH NOTES
    Relationship Between Low Irrigation Limit and Yield, Water Use Efficiency of Tomato in Under-Mulching-Drip Irrigation in Greenhouse
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    Scientia Agricultura Sinica. 2006, 39(02):  425-432 . 
    Abstract ( 3608 )   PDF (359KB) ( 2339 )   Save
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    【Objective】Based on the relation between low irrigation limit and yield, water use efficiency of tomato in under-mulching-drip irrigation in greenhouse, the optimal combination of low irrigation limits in the earlier and latter stages was studied.【Method】A field plot experiment was conducted in greenhouse and multiple regression analysis was used to deal with the experimental data.【Result】Low irrigation limits at earlier and latter stages influenced mutually water requirement and yield of tomato. Low irrigation limit at latter stage had more important effect on total water requirement than that at earlier stage, meanwhile low irrigation limit at earlier stage affected more significantly the tomato yield than that at latter stage. There was a parabola regression relationship between yield and water use efficiency. When tomato yield was 9.69×104kg·ha-1, the minimum of water use efficiency would be 62.28 kg·m-3.【Conclusion】Considered various factors, saving water, increasing yield, improving water use efficiency et al, it is advantageous to gain high yield when the soil water suction of low irrigation limits in earlier and later stage is 20 kPa and 60 kPa respectively. It is more important to enhance water management at earlier stage than that at latter stage. The results will enrich water regulation theory in under-mulching-drip irrigation in greenhouse.