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    01 July 2010, Volume 43 Issue 13
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    Identification and Mapping of a Novel Bacterial Blight Resistance Gene Xa35(t) Originatd from Oryza minuta
    GUO Si-bin,ZHANG Duan-pin,LIN Xing-hua
    Scientia Agricultura Sinica. 2010, 43(13):  2611-2618 .  doi:10.3864/j.issn.0578-1752.2010.13.001
    Abstract ( 985 )   PDF (449KB) ( 1297 )   Save
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    【Objective】 A new rice bacterial blight resistance gene from the wild rice species Oryza minuta (Acc. No. 101133) was transferred into Oryza sativa L. (IR24). Identification and molecular mapping of the resistance gene was carried out to put it into practical use in the future. 【Method】 A BC2F2 population and its F3, F4 families were used for molecular mapping of Xa35(t), and Bulked Segregant Analysis (BSA) was adopted to survey SSR markers. 【Result】 Through genetic analysis and identification of resistance spectrum, Xa35(t) showed a high level of resistance to PXO61, PXO112 and PXO339, but susceptible to PXO86 and PXO99 after inoculation with five strains of Xanthomonas oryzae pv. oryzae (Xoo), suggesting it is a new dominant bacterial blight resistance gene in the long arm of chromosome 11. With SSR marker analysis, the Xa35(t) locus was mapped to a region of about 1.80 cM. This locus, co-segregated with marker RM144, was 0.7 cM from marker RM6293 on one side and 1.1 cM from marker RM7654 on the other side in rice chromosome 11. 【Conclusion】 Genetic analysis and identification of resistance spectrum revealed that Oryza minuta (Acc. No. 101133) harbors a new rice bacterial blight resistance gene, designated as Xa35(t).

    Distribution of Vernalization Genes in Chinese Wheat Landraces and Their Relationship with Winter Hardness#br#
    JIANG Ying,HUANG Lin-zhou,HU Yin-gang
    Scientia Agricultura Sinica. 2010, 43(13):  2619-2632 .  doi:10.3864/j.issn.0578-1752.2010.13.002
    Abstract ( 1063 )   PDF (801KB) ( 1110 )   Save
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    【Objective】 The objective of this experiment is to understand the distribution of vernalization genes in Chinese wheat landraces and their relations with winter hardness so as to promote the reasonable utilization of those landraces in wheat improvement. 【Method】 Using STS markers of wheat vernalization genes Vrn-A1, Vrn-B1, Vrn-D1, and Vrn-B3, the loci distribution of those genes among 153 Chinese wheat landraces from 10 major wheat ecological regions of China were detected, and their relationship with winter hardness was analyzed. 【Result】 The frequencies of the dominant loci of the four vernalization genes in Chinese wheat landraces were 60.78% (Vrn-D1), 5.88% (Vrn-A1a), 5.23% (Vrn-B1), and 0 (Vrn-B3), respectively. The higher frequencies of Vrn-A1a and Vrn-B1 were detected in spring wheat regions, with the highest in Northeastern China Spring Wheat Region with 50% and 33.33%, respectively, while in most winter wheat regions, those loci weren’t detected. Vrn-D1 was detected in all the 10 wheat ecological regions, which also was the main locus of vernalization genes in the landraces of winter wheat regions in China and the highest frequency was detected in Qinghai-Tibet Spring-Winter Wheat Region (83.33%). The genotypes of vernalization genes in wheat landraces from 10 major wheat ecological regions of China detected by molecular marker analysis were largely consistent with their vernalization requirement, and the consistency index of genotypes detected with the winter hardness recorded from the field was higher in general, while the consistency index for the landraces from the winter wheat regions of central and southern China were lower. 【Conclusion】The types and distribution characters of vernalization genes in Chinese wheat landraces were clarified, combining molecular detection of genotype and field investigation of phenotype could reflect the winter hardness of wheat better.

    QTL Analysis of Flowering-Related Traits in Maize (Zea mays L.) Using Two Connected Populations#br#
    WANG Di,LI Yong-xiang,WANG Yang,LIU Cheng,LIU Zhi-zhai,PENG Bo,TAN Wei-wei,ZHANG Yan,SUN Bao-cheng,SHI Yun-su,SONG Yan-chun,WANG Tian-yu,LI Yu
    Scientia Agricultura Sinica. 2010, 43(13):  2633-2644 .  doi:10.3864/j.issn.0578-1752.2010.13.003
    Abstract ( 846 )   PDF (531KB) ( 1350 )   Save
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    【Objective】 Quantitative trait loci (QTL) for maize flower-related traits including days to tasseling (DTT), days to pollen-shedding (DTP), days to silking (DTS) and anthesis-silking interval (ASI) were mapped in two different F2:3 families with a shared male parent to provide reference for molecular breeding and related basic research in maize. 【Method】 230 and 235 F2:3 families derived from Qi 319×Huangzaosi population (Q/H) and Ye 478×Huangzaosi population (Y/H), respectively, under six different environments (2007-Beijing, 2008-Beijing, 2007-Henan, 2008-Henan, 2007-Xinjiang, and 2008-Xinjiang) were used to map QTL controlling four flower-related traits of maize by using the inclusive composite interval mapping method (ICIM). Meanwhile, QTL Network-2.0 was used to analyze epistasis among QTLs and QTL by environment interaction (QEI). 【Result】 Phenotypic analysis showed that DTT, DTP, DTS and ASI differed significantly in both Q/H and Y/H populations, while significant statistical correlations were observed between these flower-related traits in both populations. Under all of the six environments, 85 QTLs distributed on the 10 chromosomes were identified in Q/H, while 30 QTLs among which some were clustered were identified in Y/H for these four flower-related traits. Two and one important QTLs related to multiple traits were detected in each population, which were located on the interval of umc1562-bnlg1651 of Chrom. 8, phi062-umc1115 of Chrom. 10 and nc030-umc2166 of Chrom. 3, respectively. They could be expressed under different environments (may be called constitutive QTL). The results also indicated that those QTLs which could explain a relatively higher proportion of phenotypic variation seemed to control multiple target traits. Further, four QTLs were observed to be consistent between Q/H and Y/H. 【Conclusion】 Previous studies suggested that the genetic mechanisms of the flowering-related traits in maize are quite complicated. However, the results obtained here may give an important clue for precise mapping and positional cloning of QTL which could be stably expressed under different environments or genetic backgrounds.

    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY
    The SOI Model of Quantitative Cultivation of Super-High Yielding Rice#br#
    ZHANG Hong-cheng,WU Gui-cheng,WU Wen-ge,DAI Qi-gen,HUO Zhong-yang,XU Ke,GAO Hui,WEI Hai-yan,HUANG Xing-fu,GONG Jin-long
    Scientia Agricultura Sinica. 2010, 43(13):  2645-2660 .  doi:10.3864/j.issn.0578-1752.2010.13.004
    Abstract ( 865 )   PDF (571KB) ( 1084 )   Save
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    【Objective】 A model of cultivation for stable yield of super-high-yielding rice was studied. 【Method】 Taking the early-maturing late-japonica varieties, Wujing 15 and Changyou 1, as materials, through the nitrogen fertilizer regimes under other cultivating conditions all being the optimal,three strategic management models of cultivation were examined, i.e. SOI (stabilizing, optimizing, intensifying during the early ,middle, late phase correspondingly to adopt the ratio of basal-tillering and panicle initiating fertilizer of 50:50 and nitrogen applying leaf age of remaining leaf primordium number of 4,3), BP (balance promoting during all phase to adopt the ratio of basal-tillering and panicle initiating fertilizer of 40:60 and nitrogen applying leaf age of remaining leaf primordium number of 5, 4, 3) and PC (promoting, controlling during the early, middle phase correspondingly to adopt the ratio of basal-tillering and panicle initiating fertilizer of 75:25 and nitrogen applying leaf age of remaining leaf primordium number of 5), in contrast to the CK (A model of conventional cultivation management) in field production of one-seasoned rice in the region of the middle and lower reaches of the Yangtze River. Their results were systematically compared in various aspects, such as yielding and its components, dynamics of population stems and tillers, leaf area index, photosynthetic potential, grain-leaf ratio, production of dry matter, root activity after heading, etc. In addition, confirmatory tests on the practicability of the super high yield cultivation of the SOI model on 6.7 hectares of contiguous fields, as well as comprehensive experiments in the scale of 1-3.3 hectares, were performed using other varieties, Xudao 3, Changyou 1, Lingxiangyou 18 and Wujing 15, in the areas of Donghai, Xinghua, Gaoyou and Changshu of Jiangsu. 【Result】 The yields of SOI and BP were ranking up to the level of super-high-yield(≥750 kg/667m2)in two varieties. Compared with CK, more spikelets per panicle and population spikelets were observed in the models of SOI and BP, with roughly the same level of panicles per unit area, filled-grain percentage, and 1000-grain-weight. In the models of SOI and BP in comparison with CK, the population of stems and tillers achieved the expected number punctually at the critical leaf-age for productive tillers, and reached the peak with an appropriate value (1.3-1.4 folds of expected panicle number), then decreased gently, ultimately arrived at a significantly higher rate of productive tillers to total tillers than CK. Plants in SOI and BP models developed approximately the same population LAI dynamics and dynamics of stems and tillers, their maximal LAI appeared at the booting stage (8.0-8.5) and remained a level of 3.5-4.0 at the maturity stage. As for the population photosynthesis potential and the dry matter accumulation, the models of SOI and BP showed lower values than CK during the early stages (from transplantation to jointing stage), during the middle stages (from jointing to heading) both two models were roughly the same with CK, showing no statistical significance, and for the later stages in growth and development (from heading to maturity), two models were at remarkably higher levels in these two parameters. The two models developed a nearly dry weight of roots as compared to CK at the stage of jointing, but they developed remarkably higher than CK at heading and maturity. A pattern of evidently higher values than CK in both SOI and BP was found in such parameters as the root-shoot ratio at the stages of jointing, heading and maturity, the average root exudates after heading (from heading to waxy stage), and the ratio of spikelets to root exudates. Besides, an average yield per 667m2 was achieved, both in the comprehensive super-high-yield cultivation experiment of SOI in more than 2 consecutive years, and in the confirmatory tests for practicality in the contiguous fields of 6.7 hectares. 【Conclusion】 The results revealed that the pivotal principle for super-high-yield cultivation of rice lies in ‘strengthening the supporting system, enlarging the sink capacity, and guaranteeing the grain-filling’, and the super-high-yield cultivation mode was proposed, i.e. appropriate number of population stems and tillers with strong seedlings at early stage, high photosynthetic efficiency population structure with controlling ineffective tillers at middle stage, and enriched dry matter production with large panicles, strong stems, high efficiency leaves in proper population configuration at later stage.
    Comparative Study on Monitoring Canopy Leaf Nitrogen Status on Red Edge Position with Different Algorithms in Wheat#br#
    YAO Xia,TIAN Yong-chao,LIU Xiao-jun,CAO Wei-xing,ZHU Yan
    Scientia Agricultura Sinica. 2010, 43(13):  2661-2667 .  doi:10.3864/j.issn.0578-1752.2010.13.005
    Abstract ( 846 )   PDF (351KB) ( 786 )   Save
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    【Objective】 Red edge position (REP, 680-780 nm) has been used for evaluating crop leaves nitrogen status. The objectives of this paper were to extract REP with different algorithms, to analyze the precision and stability of the monitoring model, to ascertain the optimum REP algorithm and relevant quantitative model for nitrogen status. 【Method】 On the basis of hyperspectral reflectance and leaf nitrogen status at different growth stages under varied nitrogen rates, planting densities and wheat cultivars, this study systematically analyzed the quantitative relationships and statistical characters between red edge position on various algorithms and canopy leaf nitrogen status, and then developed the monitoring models by comparing accuracy and reliability of nitrogen estimation. 【Result】 The results showed that the monitoring models developed from the linear extrapolation method (LEM) could stably indicate canopy leaf nitrogen content (LNC) and leaf nitrogen accumulation (LNA) in wheat. 【Conclusion】 The results have provided a stable and effective approach for monitoring canopy leaf nitrogen status in wheat.

    Soil Water Conservation Effect, Yield and Income Increments of Conservation Tillage Measures in Spring Maize Field on Weibei Highland#br#
    SHANG Jin-xia,LI Jun,JIA Zhi-kuan,ZHANG Li-hua
    Scientia Agricultura Sinica. 2010, 43(13):  2668-2678 .  doi:10.3864/j.issn.0578-1752.2010.13.006
    Abstract ( 851 )   PDF (379KB) ( 804 )   Save
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    【Objective】 The objective of the experiment was to explore the effect of different conservation tillage measures combined with different fertilizer treatments on soil water conservation, grain yield and income increments in spring maize field on Weibei Highland, Shaanxi.【Method】 A two-year-field experiment was conducted to measure soil moisture in winter fallow and maize growth period with no-tillage, sub-soiling and deep plowing treatments, as well as its effects on maize yield and economic income combined with balance fertilization, traditional fertilization and no or lower fertilizer treatments were analyzed during 2007-2009. 【Result】 During winter fallow of 2 years experiment, average soil water storage amount in 0-200 cm soil layers of no-tillage and sub-soiling treatments were 33.4 mm and 31.1mm higher than deep-plowing, respectively. In maize growth period of 2 years experiment, the average soil water storage amount in 0-200 cm soil layers of no-tillage and sub-soiling treatments were 36.3mm and 37.3mm higher than deep-plowing, respectively. Maize yield and water use efficiency in treatment combination of balanced fertilization and sub-soiling were the highest among the treatments, its average yield and water use efficiency in 2 years reached 10 341.0 kg?hm-2and 24.89 kg?hm-2?mm-1, balanced fertilization and no-tillage treatment combination was in the second place, while balanced fertilization and deep-plowing treatment combination was in the third place. 【Conclusion】 With all kinds of fertilization treatments, sub-soiling tillage showed higher soil moisture conservation ability as well as higher yield and income than no-tillage and conventional tillage. So balanced fertilization and sub-soiling treatment is the most efficient treatment and should be a more suitable conservation tillage measure for spring maize cropping on Weibei Highland.

    PLANT PROTECTION
    Spectral Characteristics of Rice Leaves Damaged by Rice Leaf Roller#br#
    HUANG Jian-rong,SUN Qi-hua,LIU Xiang-dong
    Scientia Agricultura Sinica. 2010, 43(13):  2679-2687 .  doi:10.3864/j.issn.0578-1752.2010.13.007
    Abstract ( 854 )   PDF (404KB) ( 768 )   Save
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    【Objective】 The effects of the damage degree, spatial pattern, and rate of damaged leaves by rice leaf roller (RLR) on spectral characteristics of leaves were studied in this paper in order to construct models for diagnosing the damage of rice, and to attain the parameters and methodology for automatic monitoring of the rice leaf roller. 【Method】 The spectral reflectances of different damage degrees, spatial patterns and damage rates of rice leaves were measured by ASD Hand-held Spectroradiometers, and the diagnosing models based on the spectral parameters were established using the linear regression method. 【Result】 The results indicated that the spectral reflectance of rice leaf decreased in the green (530-570 nm) and near-infrared (700-1 050 nm) wave-length regions with the increase of the damage degree whereas it increased in the red wave-length region (610-700 nm). The regions of 530-564 nm, 614-695 nm and 706-1 050 nm were the sensitive wave-length bands which could reflect the impaired level of rice leaf by the RLR. Five models were established for diagnosing the damage degree of rice leaf, and their diagnosing accuracies were 80%-90%. The maximum diagnostic accuracy belonged to the model based on the reflectivity at 741 nm. The spectral reflectance of rice leaves was less impacted by the spatial pattern of the damaged leaves when the rate of the damaged leaves was constant. However, the spectral reflectivity increased significantly at 450-500 nm and 610-700 nm, but decreased at 530-570 nm and 700- 1 050 nm as the rate of damaged leaves increased. The spectral indexes including vegetation index (Rnir-Rred), the areas of the yellow-edge (SDy), and the difference of the areas of the red-edge and blue-edge (SDr-SDb) could significantly distinguish the six grades of leaf roll rates (0%, 10%, 30%, 50%, 70%, and 90%). The area of yellow edge (SDy) index could diagnose the leaf roll rate and the accuracy of diagnoses was up to 86%. 【Conclusion】 The damage of rice leaves by RLR could be monitored by the spectral reflectance. Spectral indexes could reflect the harm degree of rice leaves and the rate of infested leaves.

    Genetic Differentiation Among Poupulations of the Oriental Fruit Fly Bactrocera dorsalis (Hendel) in Chongqing Based on Microsatellite Markers #br#
    WAN Xuan-wu,LIU Ying-hong,ZHANG Bin,ZHOU Hao-dong
    Scientia Agricultura Sinica. 2010, 43(13):  2688-2696 .  doi:10.3864/j.issn.0578-1752.2010.13.008
    Abstract ( 997 )   PDF (361KB) ( 897 )   Save
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    【Objective】 The objective of the study is to discuss the genetic differentiation of the Bactrocera dorsalis (Hendel) in Chongqing region. 【Method】 One hundred and fifty-five individuals of B.dorsalis collected from 6 districts of Chongqing were divided into 6 populations and analyzed by 8 microsatellite markers to examine the genetic diversity and genetic differentiation in Chongqing region. 【Result】 A total of 51 alleles were detected at 8 loci. The range of Mean Observed Heterozygote (Ho) was from 0.1731 to 0.2958 and the range of Mean Expected Heterozygote (He) was from 0.1311 to 0.6796. The Chi-square test results argued that the 6 populations of B. dorsalis in present study did not follow with the Hardy-Weinberg Equilibrium at most loci. The analysis results of Percentage of Polymorphic Loci, Nei’s Gene Diversity and Shannon Information Index indicated that there was a high level in genetic diversity among the 6 populations of B. dorsalis. The mean Genetic Differentiation Index (FST) was 0.0777, which demonstrated that genetic differentiation mainly occurred inner-population. The utmost genetic distance (0.2367) appeared between Wulong population and Yongchuan population, meanwhile the nearest genetic distance (0.0667) occurred between Jiangjin population and Beibei population. The UPGMA phylogenetic tree showed that the 6 populations in Chongqing region clustered into two groups. Populations of Beibei, Jiangjin, Wanzhou, Xiushan, and Yongchuan merged into one group, while population from Wulong solely formed the other group.【Conclusion】 The results suggested that genetic differentiation already occurred among the 6 populations, although the degree of differentiation was low. The invasion of the oriental fruit fly in Chongqing region was at the primary stage.

    SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT
    Effects of N and Water Supply on Dry Matter and N Accumulation and Distribution in Maize (Zea mays L.) Leaf and Straw-Sheath#br#
    WANG Li-mei,LI Shi-qing,SHAO Ming-an
    Scientia Agricultura Sinica. 2010, 43(13):  2697-2705 .  doi:10.3864/j.issn.0578-1752.2010.13.009
    Abstract ( 825 )   PDF (338KB) ( 773 )   Save
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    【Objective】 The objective of this paper was to study the effects of different levels of N and water supply on the accumulation and distribution of dry matter and N in maize leaf and straw-sheath. 【Method】 A pot experiment was therefore conducted during 2008-2009 to study the dry matter and N accumulation and distribution dynamics as affected by different levels of N supply and soil water availability. 【Result】 The results showed that N concentration of leaf and straw-sheath was significantly increased with application of N fertilizer except 11-leaf stage. Adequate water supply significantly enhanced the N concentration of leaf and straw-sheath in N application treatments, however, adequate water supply did not enhance but decreased the N concentration of leaf and straw-sheath in no N application treatments. Whether N were applied or not, the dry matter accumulation of leaf and straw -sheath showed a single-peak curve with maize growing under the condition of adequate water supply, but it showed a continuous increasing trend with growing under the condition of drought stress. The N accumulation of leaf and straw-sheath showed a single-peak curve with growing in all treatments except the one which were treated with not only drought stress but also no N application (in this treatment, no significant differences were observed in N content of leaf and straw -sheath among 3 stages). Whether N and water were supplied sufficiently or not, leaf was the main part of N distribution, but the distribution of dry matter varied with N application and growing stage. When no N fertilizer was applied, the cumulative amount of dry matter in straw-sheath was higher than in leaf from spinning to grain filling stage, however, it was lower than leaf at 11-leaf stage. When N fertilizer was sufficiently supplied, the cumulative amount of dry matter in straw-sheath was always higher than in leaf during the whole growing season.【Conclusion】 The accumulation of dry matter and N in leaf and straw-sheath were asynchronous, and the accumulation curves varied with different levels of water and N supply. Leaf was the main part of N accumulation, but the main part of dry matter accumulation varied with N application and growing stage. N application and irrigation both could significantly increase the dry matter and N content in maize canopy, and the interactive effects between irrigation and N application were significant, in addition, the effect of N application was higher than irrigation in present experiment.

    Changes of Soil Ammonia-Oxidizing Bacterial Diversity in Response to Long-term Fertilization in Dry Highland of Loess Plateau#br#
    LIU Gui-ting,CHENG Lin,WANG Bao-li,ZHAO Qi-guo,QU Dong
    Scientia Agricultura Sinica. 2010, 43(13):  2706-2714 .  doi:10.3864/j.issn.0578-1752.2010.13.010
    Abstract ( 767 )   PDF (690KB) ( 1128 )   Save
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    【Objective】 In order to explicate the indicating function of ammonia-oxidizing bacteria (AOB) on changes of environmental quality and the response of AOB to different long-term fertilizations, AOB diversity and community structure in dry highland of loess plateau were studied. 【Method】 Constructed amoA gene clone libraries, and the influence of CK, M, NM, PM and NPM fertilizer treatments on soil AOB diversity and community structure were analyzed by restriction fragment length polymorphism (PCR-RFLP). 【Result】 There were 59, 56, 83, 71 and 42 restriction endonuclease types from different fertilization, respectively. α-measurement indices analysis illuminated that there was variety differentia among five fertilizer treatments. The diversity was the highest in NM treatment and the lowest in NPM treatment. The Sorenson index was 0.61 between M and NPM(M-NPM), which indicated the highest community similarity. The lowest community similarity was existed in NM-CK and PM-CK, which Sorenson indices were both 0.15. Sorenson indices of other treatments were from 0.23 to 0.38. Phylogenetic analysis of amoA gene amino acid sequences showed that Nitrosospira cluster 3 sequences was dominant in all treatments, just the proportion of clones in each treatment belonging to Nitrosospira cluster 3a or 3b was different, and some clones were affiliated with the Nitrosospira cluster 4. 【Conclusion】 The results indicated that long term fertilization resulted in change of AOB community. Different fertilizer environments could lead to the significant species variation of soil AOB.

    Changes of Black Soil Labile Organic Carbon Pool Under Different Vegetation and Fertilization Managements#br#
    ZHANG Di,HAN Xiao-zeng
    Scientia Agricultura Sinica. 2010, 43(13):  2715-2723 .  doi:10.3864/j.issn.0578-1752.2010.13.011
    Abstract ( 905 )   PDF (395KB) ( 988 )   Save
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    【Objective】 An attempt was made in this paper to investigate the dynamics of total organic C (TOC), labile organic C (CLOC) in relation to the system productivity of different black under soil long-term management strategies. 【Method】 The first experiment was designed to study the effects of different chemical compositions and complexity of residues in three grass and crop treatments, including bare fallow, grass fallow, plantation with no fertilizer on the contents of labile organic carbon of the black soil. The long-term fertilization experiment including three treatments was designed, i.e., plantation with on fertilizer (CK), chemical NP, and organic manure plus chemical NP. 【Result】 The result indicated that different residues returned into the soil had remarkable influence on the black soil labile organic carbon formation. The TOC and TN under bare fallow declined by 11.2% and 15.3% compared with those in 1985. The TOC and TN in the grass fallow was 13.2% and 5.8% higher than those in 1985. The storages of soil TOC in the plantation increased by 1.1% and TN declined by 15.5%. In contrast with the bare fallow treatment, the soil covered with plantation and grass fallow, increased by 13.9%, and 46.2% of light fraction organic nitrate and 36.48% and 62.0% of light fraction organic carbon, respectively. The sequence in the amounts of hot-water organic carbon and readily oxidizable carbon in different vegetations was grass fallow>plantation>bare fallow. In the second experiment, application of manure increased the concentrations of TOC by 25.5% and of TN by 18.6%.Compared with the CK treatment, the application of manure, fertilizer NP, increased the light fraction organic nitrate by 126.7%, and 12.17% and light fraction organic carbon by 125.14% and 17.14%, respectively. Compared with the CK and NP treatments, the application of manure increased the particulate organic nitrogen by 49.8% and 23.2% and 6.5%, and particulate organic carbon by 29.9%, respectively. The decline sequence in the amounts of hot-water organic carbon and readily oxidizable carbon in soils under cropping was CK<NP<NPOM. 【Conclusion】Grass cover and NPOM treatments are beneficial to the soil organic carbon and labile organic carbon accumulation.

    HORTICULTURE
    Research Progress on the Factors Related to Tomato Fruit Ripening and Senescence#br#
    ZUO Jin-hua,CHEN An-jun,SUN Ai-dong,LUO Yun-bo,ZHU Ben-zhong
    Scientia Agricultura Sinica. 2010, 43(13):  2724-2734 .  doi:10.3864/j.issn.0578-1752.2010.13.012
    Abstract ( 829 )   PDF (349KB) ( 1472 )   Save
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    Tomato fruit ripening and senescence is an ordered, complicated and also a highly harmonious genetic regulation process, which are influenced by various factors, including all kinds of plant hormones, related enzymes and many exogenous materials. This paper discussed the effects of related plant hormones and its analogues (ethylene, abscisic acid, salicylic acid, jasmonic acid, polyamines), related enzymes(lipoxygenase, protective enzymes, softening related enzymes), and exogenous materials (1-methylcyclopropene, nitric oxide, calcium) on the ripening and senescence of tomato fruit and the influence mechanisms of various factors.

    Cloning, Sequence Analysis and Expression in E.coli of MsMYB10 Gene from Malus sieversii f. neidzwetzkyana#br#
    WANG Yan-ling,ZHANG Yan-min,FENG Shou-qian,TIAN Chang-ping,WANG Hai-bo,LIU Zun-chun,SONG Yang,CHEN Xue-sen
    Scientia Agricultura Sinica. 2010, 43(13):  2735-2743 .  doi:10.3864/j.issn.0578-1752.2010.13.013
    Abstract ( 1030 )   PDF (920KB) ( 979 )   Save
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    【Objective】 Cloning, sequence analysis and expression in E. coli of MsMYB10 gene from Malus sieversii f. neidzwetzkyana was conducted to further explore the red development mechanism and breed cultivars of red-flesh apple. 【Method】A cDNA fragment about 700 bp was amplified from the total RNA of leaves of Malus sieversii f. neidzwetzkyana by reverse transcription PCR(RT-PCR) with a pair of specific primers based on the sequences of MdMYB10. The recombinant prokaryotic expression vector pET30a-MsMYB10 was constructed by inserting the cDNA fragment into the prokaryotic expression vector pET-30a, and then transformed into E. coli BL21(DE3). 【Results】 Sequence analysis showed that the fragment contains a full coding region of 732 bp encoding 244 amino acid residues with a molecular mass of 28.56 kD. Its GenBank accession number is GQ500894. This deduced protein has a pI of 8.41. Results of the study showed that MsMYB10 exhibited typical features of the R2R3-MYB domain. Tryptophan residues are conserved in R2R3 domain. There is one transcriptional activation domain rich in acidic amino acids in the C-terminal. MsMYB10 exhibits a homology of 99% and 98% with MdMYB10 in nucleotide and amino acid levels, respectively. MsMYB10 has no signal peptide, but a nuclear localization signal. The homology tree showed that MsMYB10 is at the same evolutionary branch with MdMYB10. The SDS-PAGE displays that the expressed proteins consistent with the size of expected protein. 【Conclusion】 MsMYB10 was cloned from Malus and expressed in E. coli. These results have provided a foundation for further purifying and identifying target protein and function study of MsMYB10.

    Influence of Heat Stress on Photosynthesis in Vitis vinifera L. cv. Cabernet Sauvignon #br#
    LUO Hai-bo,MA Ling,DUAN Wei,LI Shao-hua,WANG Li-jun
    Scientia Agricultura Sinica. 2010, 43(13):  2744-2750 .  doi:10.3864/j.issn.0578-1752.2010.13.014
    Abstract ( 844 )   PDF (405KB) ( 930 )   Save
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    【Objective】 Changes in photosynthesis in Vitis vinifera L. cv. Cabernet Sauvignon exposed to high temperature for extended periods and following recovery were investigated to reveal the mechanism of inhibition and recovery of photosynthesis. 【Method】 Two years old Cabernet Sauvignon grapevines were treated for 6 d at high temperature (40℃ from 9:30 to 15:30 and 30℃ during the rest of each day) and then at the same temperatures as the controls. The controls were treated at 30℃ from 6:30 to18:30 and 20℃ during the remainder of each day. Gas exchange and chlorophyll fluorescence parameters were measured before and during high temperature and following recovery. 【Result】 With heat stress, net photosynthetic rate (Pn), stomatal conductance (Gs), the actual PSⅡ efficiency (ΦPSII), the photochemical quenching coefficient (qP), and amount of active PSⅡ RCs per CS (RC/CSo) decreased, intercellular CO2 concentration (Ci), non-photochemical quenching (NPQ), and the damage of oxygen evolving complex indicated by WK, the probability that a trapped exciton moves an electron into the electron transport chain beyond QA- (ψEo) increased. When the grapevines recovered for 1 d from heat stress, the values of these parameters were similar to those in the controls. 【Conclusion】 Pn was decreased by heat stress at 40℃, but recovered to the control level after 1 d. The decrease in Pn were not due to stomatal limitations, but were associated with the donor side and reactive center of PSⅡ. The increase in Pn should be associated with the above all factors.

    Relationship Between Salicylic Acid and Iron in Their Regulations of the Growth of Strawberry Tissue Culture Plants#br#
    LI Shu-ping,YUAN Yong-bing,LIU Geng-sen,LIU Cheng-lian,WANG Yong-zhang,LI Pei-huan
    Scientia Agricultura Sinica. 2010, 43(13):  2751-2758 .  doi:10.3864/j.issn.0578-1752.2010.13.015
    Abstract ( 1062 )   PDF (309KB) ( 1087 )   Save
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    【Objective】 In order to explain the mechanism on the roles of salicylic acid in plant physiology and development, tissue culture plants of strawberry were used to explore the possible interactions between SA and iron. 【Method】 SA at a series of concentrations (0.05-0.8 mmol?L-1 ) was applied to the medium with a series of concentrations (0.05-0.8 mmol?L-1 ) of iron. Plant growth and the activities of some iron enzymes were measured. 【Result】 The plants were shown to be more sensitive to SA in the medium with lower concentrations of iron than higher ones. The optimal concentrations of SA for plant growth increased gradually along with the increase of iron concentrations in the medium. SA usually inhibited root elongation. Low concentrations of SA increased the plant height and chlorophyll content while high concentrations of SA reduced these indices. Higher concentration of SA at 0.4 mmol?L-1 injured the plants, but such injury became less with the increase of the concentration of iron. The activities of CAT and ACO were enhanced by SA at the concentrations of 0.05-0.2 mmol?L-1 while reduced at 0.4 mmol?L-1. POD activity was increased by SA at 0.05-0.4 mmol?L-1. 【Conclusion】 SA and iron have close relationship in regulating the growth of strawberry.

    STORAGE·FRESH-KEEPING·PROCESSING
    Emulsion Properties of Pectin Extracted from Sweetpotato Starch Residues#br#
    MEI Xin,MU Tai-hua,GUO Qing
    Scientia Agricultura Sinica. 2010, 43(13):  2759-2766 .  doi:10.3864/j.issn.0578-1752.2010.13.016
    Abstract ( 796 )   PDF (367KB) ( 1219 )   Save
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    【Objective】 In order to provide a theoretical basis for development and utilization of the pectin resources in sweetpotato residues, the characteristics of pectin and its emulsion properties were investigated. 【Method】 The pectin was extracted by using hydrochloric acid solution, in which, the galacturonic acid content, degree of esterification (DE) and molecular weight were determined by carbazole and sulphuric acid spectrophotometric determination method, titration method and HPLC, respectively. The effects of different pectin concentrations (0.5%-4.0%, w/v) and oil-phase volume fraction (5%-40%, v/v) on emulsion properties of sweetpotato pectin were studied. 【Result】 The galacturonic content, DE and molecular weight of sweetpotato pectin were 73.28%, 31.71% and 292 kD, respectively. With increasing the pectin concentration, the particle size (d4,3) of emulsion decreased, while adsorbed fraction of pectin onto emulsion droplets, apparent viscosity of emulsion, the emulsion activity (EA) and emulsion stability (ES) of emulsion increased (P<0.05). Furthermore, with increasing the oil-phase volume fraction, d43, EA and the apparent viscosity of emulsion increased (P<0.05), whereas the value of adsorbed fraction of pectin onto emulsion droplets and ES presented a trend of increasing firstly and then decreasing. 【Conclusion】 Sweetpotato starch residues is a kind of potential resource for pectin extraction, the pectin extracted by using acid solution belongs to low methoxy pectin, which has excellent emulsion ability and emulsion stability.

    Effect of NO on Oxidative Damage to Mitochondrial Membrane in Harvested Plum Fruit#br#
    YAO Ting-ting,ZHU Li-qin,YANG Shuang,ZHOU Jie,ZHU Shu-hua
    Scientia Agricultura Sinica. 2010, 43(13):  2767-2774 .  doi:10.3864/j.issn.0578-1752.2010.13.017
    Abstract ( 748 )   PDF (335KB) ( 896 )   Save
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    【Objective】 This paper aimed to study the effects of nitric oxide (NO) on oxidative damage by reactive oxygen species (ROS) to mitochondrial membrane in harvested plum fruit (Prunus salicina Lindl.). 【Method】 The plum fruits were fumigated with 0, 10, 15 and 30 μL?L-1 NO gas and then stored for 13 days at 25℃. The physiological and biochemical properties, including respiration, contents of hydroperoxide and superoxide radical, activities of superoxidase (SOD), catalase (CAT) and peroxidase (POD), the opening of mitochondrial permeability transition pores, electric potential and cytochrome c/a were determined. 【Result】 Compared with the control and treatment with 10 or 30 μL?L-1 NO, treatment with 15 μL?L-1 NO increased the activities of SOD, CAT and POD, decreased effectively the contents of hydroperoxides and superoxide radical, inhibited the opening of mitochondrial permeability transition pores, delayed the increase of mitochondrial permeability and Cyt c/a, maintained high electric potential. With high concentration of NO, the protection by treatment with 30 μL?L-1 NO reduced. 【Conclusion】 Application of 15 μL?L-1 NO can effectively alleviate oxidative damage by ROS to mitochondrial membrane in harvested plum fruits, protect the integrity of mitochondrial membrane.

    Flavonoid Content of the Leaves and Pollen of Male Ginkgo biloba Plants#br#
    LI Wei-xing,ZHEN Zhen,ZHOU Chun-hua,ZHANG Xiu-ping,YU Jian-you,CHEN Peng
    Scientia Agricultura Sinica. 2010, 43(13):  2775-2783 .  doi:10.3864/j.issn.0578-1752.2010.13.018
    Abstract ( 869 )   PDF (246KB) ( 944 )   Save
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    【Objective】 To provide a theoretical evidence for the development and utilization of Ginkgo biloba male plant germplasm resources, the major flavonoid components and content of the leaves and pollen of 46 male ginkgo plants from Jiangsu province were studied. 【Method】 The flavonoid aglycone content of the methanol (ethanol)- hydrochloric acid solution of leaves and pollen of different male strains were determined by HPLC. The flavonoid glycoside content of the samples were calculated according to the three-factor method. 【Result】 Significant differences were existed between the total flavonoid content of leaves and pollen in different male plants. Four strains from Yangzhou (Yangzhou 03, 04, 10 and 20), two strains from Taizhou (Taizhou 08 and 13) and two strains from Xuzhou (Xuzhou 04 and 09) met with the standard of leaf utilization, and ten strains from Yangzhou (Yangzhou 02, 03, 04, 08, 09, 10, 12, 15, 18 and 20) met with the standard of pollen utilization by setting the choice threshold of flavonoid aglycone and total flavonoids content. The leaves and pollen of different male ginkgo plants both contained three flavonoid aglycones (quercetin, kaempferol and isorhamnetin), but the amount of each differed between leaf and pollen. There was little difference in the content of individual flavonoid aglycones in leaves, whereas kaempferol was the main flavonoid aglycone in pollen. The average total flavonoid content of pollen was about 1.42 times that of the leaves. 【Conclusion】 According to the choice of setting targets, either the leaf or pollen of male ginkgo plants were selected for production based on the analysis of flavonoid aglycone and total flavonoid contents. The results have provided a theoretical basis for the use of male ginkgo plant resources.

    ANIMAL SCIENCE·RESOURCE INSECT
    Polymorphism of 3′-UTR of Fatty Acid Synthase (FAS) Gene in Five Chinese Sheep Breeds#br#
    YANG Ju-tian,XU Hong-wei,ZANG Rong-xin,CAI Yong,LU Jian-xiong,CAO Xin,HUO Sheng-dong,LIU Gen-di,WU Jian-ping
    Scientia Agricultura Sinica. 2010, 43(13):  2784-2792 .  doi:10.3864/j.issn.0578-1752.2010.13.019
    Abstract ( 956 )   PDF (464KB) ( 635 )   Save
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    【Objective】 Genetic polymorphisms of FAS gene in sheep were detected in order to provide a theoretical foundation for further studying on the genetic differentiation among sheep breeds, association analysis on sheep meat quality traits and polymorphism, location and expression regulation of sheep FAS gene, and so on. 【Method]】 PCR-SSCP and DNA sequencing approaches were applied to assess the single nucleotide polymorphisms (SNPs) and analyze the genetic polymorphisms at 3′-UTR of FAS (Fatty acid synthase) gene of five Chinese sheep breeds including Lanzhou fat-tailed sheep (LT, 38),Tan sheep (Tan, 58), Oula sheep (OL, 30), Ganjia sheep (GJ, 40) and Qiaoke sheep (QK, 39) in this study. 【Result】 2 SNPs (951SNPs and 1 005SNPs) were observed in 3’-UTR of sheep FAS gene, and 3 genotypes (AA, Aa, aa and EE, Ee, ee) were detected, respectively. AA, Aa and EE, Ee were observed in all the 5 Chinese sheep breeds, but aa and ee genotypes were not detected in any breed. AA and EE were the genotype with the highest frequency in all of the sheep breed. The predominant alleles were alleles A and E, whose frequency was higher than a and e in all the 5 breeds. Compatibility test indicated that Lanzhou fat-tailed sheep, Tan sheep, Oula sheep, Ganjia sheep and Qiaoke sheep were all in the Hardy-Weinberg equilibrium at 2 SNPs. Independence test indicated that: at 951 SNPs site the genotype distribution was obviously different between Lanzhou fat-tailed sheep and other all sheep breeds (Tan sheep, Oula sheep, Ganjia sheep and Qiaoke sheep) (0.01<P<0.05), and it was extremely obviously different between Tan sheep and other sheep breeds (Oula sheep, Ganjia sheep and Qiaoke sheep)(P<0.01),while it was not obvious between Oula sheep and other two sheep breeds (Ganjia sheep and Qiaoke sheep)(P>0.05). At 1 005 SNPs site it was not obvious between all of the 5 sheep breed (P>0.05). Sequencing analysis showed that 2 mutations (GSA) occurred at the 951 site (C→T) and 1 005 site (A→G) of 3′-UTR of transcription product of FAS gene. Secondary structure prediction of the different genotypes of mRNA in FAS gene indicated that 951SNPs could lead to significant changes in secondary structure, while the 1 005 SNPs did not change its secondary structure. 【Conclusion】 2 SNPs were observed in 3′-UTR of sheep FAS gene, which resulted from 2 single base mutation. At 2 SNPs site, Lanzhou fat-tailed sheep, Tan sheep, Oula sheep, Ganjia sheep and Qiaoke sheep were all in the Hardy-Weinberg equilibrium, but at 951 SNPs site the genotype distribution was obviously different between Lanzhou fat-tailed sheep and other all sheep breeds (Tan sheep, Oula sheep, Ganjia sheep and Qiaoke sheep), and it was extremely obviously different between Tan sheep and other sheep breeds (Oula sheep, Ganjia sheep and Qiaoke sheep),while it was not obvious between Oula sheep and other two sheep breeds (Ganjia sheep and Qiaoke sheep). At 1 005 SNPs site it was not obvious among all of the 5 Chinese sheep breeds.

    Construction of Eukaryotic Expression Vector of Bovine myf6 Gene and Expression of the Gene in Myoblasts
    TANG Zhan-yi,YAN Yun-qin,GAO Xue-jun,LU Li-min,ZHU Dan-dan,JI Zhi-geng
    Scientia Agricultura Sinica. 2010, 43(13):  2793-2799 .  doi:10.3864/j.issn.0578-1752.2010.13.020
    Abstract ( 757 )   PDF (511KB) ( 854 )   Save
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    【Objective】 The objective of the study is to construct the eukaryotic expression vector of bovine myf6 gene and analyse the change of gene expression and cell morphology of transfected myoblasts. 【Method】 Eukaryotic expression vector pIRES2-EGFP-myf6 was constructed by insert myf6 in the MCS. Liposome techinigue was used to transfect Luxi cattle myoblasts , and by G418 selection, a stable transfected cell line was gained. The changes of gene expression of myoblasts were analyzed by western blot and real-time PCR.【Result】 Compared with the control group,the results showed that, after myoblasts transfected by plasmid, the protein and mRNA expression levels of myf6 were both increased (P<0.01), muscle creatine kinase gene (P<0.01) and myosin light chain gene mRNA expression were both increased (P<0.01). Morphology observations indicated that myoblast had fused to myotubes. 【Conclusion】Eukaryotic expression vector pIRES2-EGFP-myf6 can highly express in myoblasts. The results suggest that myf6 gene can promote myoblasts differentiation.

    Enhancement of Heat Tolerance in Mice Early Embryos by TCZB-Culture Medium#br#
    WANG Kai,TIAN Wen-ru,GAO Shan-song
    Scientia Agricultura Sinica. 2010, 43(13):  2800-2805 .  doi:10.3864/j.issn.0578-1752.2010.13.021
    Abstract ( 771 )   PDF (537KB) ( 675 )   Save
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    【Objective】 The modified CZB medium - TCZB for the development of mouse preimplantation embryos was investigated to find a new medium which could increase the heat tolerance of the embryos. 【Method】 The method of prokaryotic expression was used to get Tat-Hsp70 and this Tat-Hsp70 protein was added to CZB medium to prepare TCZB medium. The embryonic development rate (EDR) and hatching rate (HR) between heat stressed group and control group were compared. 【Result】There was no significant difference in EDR and HR among groups of CZB, TCZB and control after heat stressed at 39℃; however, after treatment at 41℃, both EDR and HR of the control group (83.7±6.1,75.6±4.5) were significantly higher than tnat of both TCZB group (81.3±4.5,76.5±7.6) (P<0.05) and CZB group (80.2±5.4,73.4±6.2) (P<0.05), and both EDR and HR in the TCZB group was significantly higher than that of CZB group. 【Conclusion】 TCZB improves both EDR and HR of mouse preimplantation embryos heat stressed at 41℃.

    VETERINARY SCIENCE
    Toxic Effects of Ribavirin on Pigs
    YU Hong,SUN Hong-lei,YANG Feng,LI Hong-min,LIU Si-dang
    Scientia Agricultura Sinica. 2010, 43(13):  2806-2812 .  doi:10.3864/j.issn.0578-1752.2010.13.022
    Abstract ( 804 )   PDF (446KB) ( 755 )   Save
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    【Objective】 The aim of this study was to investigate the toxic effect of different doses of ribavirin on pigs.【Method】 Twelve pigs were randomly divided into 4 groups including a control group and three experimental groups in order to investigate the toxic effect of different doses of ribavirin on pigs. Ribavirin was administered once daily for 10 consecutive days at a dose of either 10, 30, or 90 mg?kg-1. The toxic effects were observed by ethology, blood, serum, urine, bone marrow and pathologic changes before and after administation. 【Result】 The results of this study in pigs indicated that there was no intoxicated significant toxic change between the experimental groups with a daily administration of ribavirin at a dose of 10 mg?kg-1 and the control group, but daily administration of ribavirin at a doses of 30 to 90 mg?kg-1 induced a dose-related toxic effect. The toxic effect showed that the pantropic toxicity and pathological changes in blood, bone marrow, gastrointestinal tract, pancreas, heart, liver, kidney and brain.Hemolytic anemia was the primary mechanism for the pathogenesis of pig poisoning, the reasons which resulted in the loss of appetite and constipation were catarrhal inflammation and necrotizing inflammation of gastrointestinal tract and pancreatopathy. 【Conclusion】 In summary, high doses of ribavirin can increase the risk of death of pigs, so the use of ribavirin for the treatment of swine diseases is not recommended.

    Study on Prediction Model of Eprinomectin Residue in Bovine Tissues After Subcutaneous Administration#br#
    JIANG Hai-yang,WU Cong-ming,DING Shuang-yang,ZHAO Si-jun,XU Fei,LI Jian-cheng,XIA Xi,LIU Jin-feng,SHEN Jian-zhong
    Scientia Agricultura Sinica. 2010, 43(13):  2813-2819 .  doi:10.3864/j.issn.0578-1752.2010.13.023
    Abstract ( 1002 )   PDF (301KB) ( 639 )   Save
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    【Objective】 The aim of this research is to find the relationship to eprinomectin (EPR) residue amount in bovine blood, urine, feces, hair and tissues including muscle, liver, kidney and fat and develop prediction models. 【Method】 Twenty-four parasite-free cross cattle were administered subcutaneously with 1% EPR injectable oil formulation at a dose of 0.5 mg?kg-1 body weight. Three treated animals (two males and one female) were selected randomly and killed at 1, 3, 7, 14, 21, 28, 42 and 56 days after injection. The samples mentioned above were collected and analyzed. 【Results】 The relative coefficients of prediction model regress equations fitted using SPSS 13.0 software with EPR residue concentration in blood in elimination phrase as independent variable were more than 0.9. The F test was used to analyze goodness of fit for equations with P values lower than 0.001. The relative coefficients of prediction model regress equations with EPR residue concentration in feces in elimination phrase as independent variable were more than 0.8. The F test used to analyze goodness of fit for equations with P values was lower than 0.001. 【Conclusion】 These results demonstrated that the prediction models had statistical significance and furthermore revealed that there is a strong correlation between amounts of EPR residue in blood or feces and edible tissues.

    RESEARCH NOTES
    Syudy on maize potential production of different ecoregion

    LIU Yue-e,XIE Rui-zhi,ZHANG Hou-bao,LI Shao-kun,GAO Shi-ju

    Scientia Agricultura Sinica. 2010, 43(13):  2820-2828 .  doi:10.3864/j.issn.0578-1752.2010.13.024
    Abstract ( 825 )   PDF (360KB) ( 970 )   Save
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    【Objective】 The objective of this experiment was to study the yield increasing effects and ecological adaption of the maize of timely late harvest technology on a large regional scale, and to provide a theoretical basis for maize production. 【Method】 41 experiment sites were set up in the main maize producing areas (Northeast China, North China and Huanghuaihai area ) in 2007 and 2008 to study the yield increasing effects of the maize of timely late harvest . This experiment was set up with two treatments of putting off 7 days’ harvest and putting off 14 days’ harvest. 【Result】 Timely late harvest had significant increasing effects on maize yield and 1000-grain-weight. With putting off 7 days’ harvest, the maize yield increased by 4.20% and 4.94% compared to CK in 2007 and 2008. With putting off 14 days’ harvest , the yield increased by 7.79% and 7.92% compared to CK. The yield increasing effects of the maize of timely late harvest increased with latitude decreasing (Northeast China<North China<Huanghuaihai area). The yield increasing range of putting off 7 days’ harvest were 0.08%?d-1 and 0.06%?d-1 in 2007 and 2008 with 1 degree decreasing in latitude. The yield increase range of putting off 14 days’ harvest were 0.06%?d-1 and 0.07%?d-1 in 2007 and 2008 with 1 degree decreasing in latitude. Maize timely late harvest improved the utilization efficiency of light and temperature. The ≥10℃ accumulated temperature were increased by 109.5℃ and 194.5℃ compared to CK when put off 7 days and 14 days harvest. At the same time, the sunshine duration were increased by 44.55 h and 83.38 h. 【Conclusion】 Timely late harvest has significant increasing effects on maize yield and the range increases with latitude decreasing. Appropriate late harvest time are related to local ecological conditions.