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    Genetics& Breeding· Germplasm Resources · Molecular Genetics
    Conditional QTL Mapping of Sedimentation Volume on Seven Quality Traits in Common Wheat
    DENG Zhi-ying, ZHAO Liang, LIU Bin, ZHANG Kun-pu, CHEN Jian-sheng, QU Hou-lan, SUN Cai-ling, ZHANG Yong-xiang , TIAN Ji-chun
    2013, 12(12): 2125-2133.  DOI: 10.1016/S2095-3119(13)60352-4
    Abstract ( )   PDF in ScienceDirect  
    To evaluate the possible genetic interrelationships between flour components and the sedimentation volume (SD), a doubled haploid (DH) population comprising 168 lines were used to identify the conditional quantitative trait loci (QTLs) for SD in three environments. Ten additive QTLs and 15 pairs of epistatic QTLs were detected for SD through unconditional and conditional QTL mapping. Three major additive QTLs were detected for SD conditioned on the seven quality traits. Two additive QTLs were found to be independent of these traits. Three additive QTLs were suppressed by three of the seven traits because of non-detection in unconditional mapping. Three pairs of epistatic QTLs were completely affected by the seven traits because of detection in unconditional mapping but no-detection in conditional mapping. Twelve pairs of epistatic QTLs were detected in conditional mapping. Our results indicated that conditional mapping could contribute to a better understanding of the interdependence of different and closely correlated traits at the QTL molecular level, especially some minor QTLs were found. The conditional mapping approach provides new insights that will make it possible to avoid the disadvantages of different traits by breeding through molecular design.
    Crop Genetics · Breeding · Germplasm Resources
    Optimization of Agrobacterium tumefaciens-Mediated Immature Embryo Transformation System and Transformation of Glyphosate-Resistant Gene 2mG2-EPSPS in Maize (Zea mays L.)
    YUGui-rong12 , LIUYan3 , DUWen-ping2 , SONGJun2 , LINMin4 , XULi-yuan2 , XIAOFang-ming5
    2013, 12(12): 2134-2142.  DOI: 10.1016/S2095-3119(13)60567-5
    Abstract ( )   PDF in ScienceDirect  
    Since maize is one of the most important cereal crops in the world, establishment of an efficient genetic transformation system is critical for its improvement. In the current study, several elite corn lines were tested for suitability of Agrobacterium tumefaciens-mediated transformation by using immature embryos as explants. Infection ability and efficiency of transformation of A. tumefaciens sp. strains EHA105 and LBA4404, different heat treatment times of immature embryos before infection, influence of L-cysteine addition in co-cultivation medium after transformation, and how different ways of selection and cultivation influence the efficiency of transformation were compared. Glyphosate-resistant gene 2mG2-EPSPS was transformed into several typical maize genotypes including 78599, Zong 31 and BA, under the optimum conditions. Results showed that the hypervirulent Agrobacterium tumefaciens sp. strain EHA105 was more infectious than LBA4404. Inclusion of L-cysteine (100 mg L-1) in co-cultivation medium, and heating of the immature embryos for 3 min prior to infection led to a significant increase in the transformation efficiency. Growth in resting medium for 4-10 d and delaying selection was beneficial to the survival of resistant calli. During induction of germination, adding a high concentration of 6-BA (5 mg L-1) and a low concentration of 2,4-D (0.2 mg L-1) to regeneration medium significantly enhanced germination percentage. Using the optimized transformation procedure, more than 800 transgenic plants were obtained from 78599, Zong 31 and BA. By spraying herbicide glyphosate on leaves of transgenic lines, we identified 66 primary glyphosate-resistant plants. The transformation efficiency was 8.2%. PCR and Southern-blot analyses confirmed the integration of the transgenes in the maize genome.
    Genetic Analysis and Preliminary Mapping of a Highly Male-Sterile Gene in Foxtail Millet (Setaria italica L. Beauv.) Using SSR Markers
    WANG Jun, WANG Zhi-lan, YANG Hui-qing, YUAN Feng, GUO Er-hu, TIAN Gang, AN Yuan
    2013, 12(12): 2143-2148.  DOI: 10.1016/S2095-3119(13)60392-5
    Abstract ( )   PDF in ScienceDirect  
    Breeding of male-sterile lines has become the mainstream for the heterosis utilization in foxtail millet, but the genetic basis of most male-sterile lines used for the hybrid is still an area to be elucidated. In this study, a highly male-sterile line Gao146A was investigated. Genetic analysis indicated that the highly male-sterile phenotype was controlled by a single recessive gene a single recessive gene. Using F2 population derived from cross Gao146A/K103, one gene controlling the highly male- sterility, tentatively named as ms1, which linked to SSR marker b234 with genetic distance of 16.7 cM, was mapped on the chromosome VI. These results not only laid the foundation for fine mapping of this highly male-sterile gene, but also helped to accelerate the improvement of highly male-sterile lines by using molecular marker assisted breeding method.
    Molecular Cloning, Expression Analysis and Localization of Exo70A1 Related to Self Incompatibility in Non-Heading Chinese Cabbage (Brassica campestris ssp. chinensis)
    WANG Li, GE Ting-ting, PENG Hai-tao, WANG Cheng, LIU Tong-kun, HOU Xi-lin
    2013, 12(12): 2149-2156.  DOI: 10.1016/S2095-3119(13)60580-8
    Abstract ( )   PDF in ScienceDirect  
    The exocyst is a conserved protein complex, and required for vesicles tethering, fusion and polarized exocytosis. Exo70A1, the exocyst subunit, is essential for assembly of the exocyst complex. To better understand potential roles of Exo70A1 in non-heading Chinese cabbage (Brassica campestris ssp. chinensis), we obtained the full-length cDNA of Exo70A1 gene, which consisted of 1 917 bp and encoded a protein of 638 amino acids. BlastX showed BcExo70A1 shared 94.9% identity with Brassica oleracea var. acephala (AEI26267.1), and clustered into a same group with other homologues in B. oleracea var. acephala and Brassica napus. Subcellular localization analysis showed BcExo70A1 was localized to punctate structures in cytosol of onion epithelial cells. Results showed that BcExo70A1 was widely presented in stamens, young stems, petals, unpollinated pistils, roots and leaves of self compatible and incompatible plants. The transcripts of BcExo70A1 in non- heading Chinese cabbage declined during initial 1.5 h after incompatible pollination, while an opposite trend was presented after compatible pollination. Our study reveals that BcExo70A1 could play essential roles in plant growth and development, and is related to the rejection of self pollen in non-heading Chinese cabbage.
    Physiology & Biochentry · Tillage · Cultivation
    Effects of Elevated Ozone Concentration on Starch and Starch Synthesis Enzymes of Yangmai 16 Under Fully Open-Air Field Conditions
    ZHANG Ru-biao, HU Hai-juan, ZHAO Zheng, YANG Dan-dan, ZHU Xin-kai, GUO Wen-shan
    2013, 12(12): 2157-2163.  DOI: 10.1016/S2095-3119(13)60345-7
    Abstract ( )   PDF in ScienceDirect  
    O3 is not only greenhouse gas but also a primary gaseous contaminant in the atmosphere. It has long-lasting effects on crop growth, yield and quality, and brings a series of ecological and environmental problems. A free-air controlled enrichment (FACE) system was applied to study the effect of elevated ozone concentration on activities of key enzymes of starch synthesis of Yangmai 16 in 2009-2010. The main-plot treatment had two levels of O3: ambient level (A-O3) and 50% higher than ambient level (E-O3). The main results were that accumulation rate of amylose, amylopectin and starch were represented in a single peak curve, and their content and accumulation amount rose gradually. The O3 elevation decreased the accumulation rate of amylose, amylopectin and starch amylase, reduced the accumulation amount of amylopectin and starch, and decreased the content of amylopectin and starch, but increased the content of amylose. With the increase of O3 concentration, the enzyme activity of grain granule-bound starch synthase (GBSS), soluble starch synthase (SSS) and starch branching enzyme (SBE) decreased after anthesis. The activities of GBSS and SSS had highly significant correlations with amylose, amylopectin and starch accumulation rate, and the activity of SBE had significant correlations with these items. So the O3 elevation decreased the activity of key enzymes of starch synthesis, which led to the variation of starch synthesis. Key words:
    Effects of Nitrogen Application on Chlorophyll Fluorescence Parameters and Leaf Gas Exchange in Naked Oat
    LIN Ye-chun, HU Yue-gao, REN Chang-zhong, GUO Lai-chun, WANG Chun-long, JIANG Ying
    2013, 12(12): 2164-2171.  DOI: 10.1016/S2095-3119(13)60346-9
    Abstract ( )   PDF in ScienceDirect  
    Naked oat (Avena nuda L.) was originated from China, where soil nitrogen (N) is low availability. The responses of chlorophyll (Chl.) fluorescence parameters and leaf gas exchange to N application were analysed in this study. After the N application rate ranged from 60 to 120 kg ha-1, variable fluorescence (Fv), the maximal fluorescence (Fm), the maximal photochemical efficiency (Fv/Fm), quantum yield (ΦPS II) of the photosynthetic system II (PS II), electron transport rate (ETR), and photochemical quenching coefficient (qP) increased with N application level, however, non-photochemical quenching coefficient (qN) decreased. Moreover, there was no difference in initial fluorescence (Fo) with further more N enhancement. The maximum net photosynthetic rate (Pmax), apparent dark respiration rate (Rd) and light saturation point (LSP) were improved with 40-56 kg N ha-1 as basal fertilizer and 24-40 kg N ha-1 as top dressing fertilizer applied at jointing stage. Initial quantum yield (α) was decreased with 24 kg N ha-1 as basal fertilizer and 56 kg N ha-1 as top dressing fertilizer. Flag-leaf net photosynthetic rate (Pn) was significantly enhanced at the jointing and heading stages with 40-56 kg N ha-1 as basal fertilizer; in addition, increased at grain filling stage of naked oat with 40-56 kg N ha-1 as top dressing fertilizer. 90 kg N ha-1 (50-70% as basal fertilizer and 30-50% as top dressing fertilizer) application is recommended to alleviate photodamage of photosystem and improve the photosynthetic rate in naked oat.
    Regulation of Calcium on Peanut Photosynthesis Under Low Night Temperature Stress
    LIU Yi-fei, HAN Xiao-ri, ZHAN Xiu-mei, YANG Jin-feng, WANG Yu-zhi, SONG Qiao-bo , CHEN
    2013, 12(12): 2172-2178.  DOI: 10.1016/S2095-3119(13)60411-6
    Abstract ( )   PDF in ScienceDirect  
    The effects of different levels of CaCl2 on photosynthesis under low night temperature (8°C) stress in peanuts were studied in order to find out the appropriate concentration of Ca2+ through the artificial climate chamber potted culture test. The results indicated that Ca2+, by means of improving the stomatal conductivity of peanut leaves under low night temperature stress, may mitigate the decline of photosynthetic rate in the peanut leaves. The regulation with 15 mmol L-1 CaCl2 (Ca15) was the most effective, compared with other treatments. Subsequently, the improvement of Ca2+ on peanut photosynthesis under low night temperature stress was validated further through spraying with Ca15, Ca2+ chelator (ethylene glycol bis(2-aminoethyl) tetraacetic acid; EGTA) and calmodulin antagonists (trifluonerazine; TFP). And CaM (Ca2+-modulin) played an important role in the nutritional signal transduction for Ca2+ mitigating photosynthesis limitations in peanuts under low night temperature stress.
    Subsoiling and Ridge Tillage Alleviate the High Temperature Stress in Spring Maize in the North China Plain
    TAO Zhi-qiang, SUI Peng, CHEN Yuan-quan, LI Chao, NIE Zi-jin, YUAN Shu-fen, SHI Jiangtao
    2013, 12(12): 2179-2188.  DOI: 10.1016/S2095-3119(13)60347-0
    Abstract ( )   PDF in ScienceDirect  
    High temperature stress (HTS) on spring maize (Zea mays L.) during the filling stage is the key factor that limits the yield increase in the North China Plain (NCP). Subsoiling (SS) and ridge tillage (R) were introduced to enhance the ability of spring maize to resist HTS during the filling stage. The field experiments were conducted during the 2011 and 2012 maize growing seasons at Wuqiao County, Hebei Province, China. Compared with rotary tillage (RT), the net photosynthetic rate, stomatal conductance, transpiration rate, and chlorophyll relative content (SPAD) of maize leaves was increased by 40.0, 42.6, 12.8, and 29.7% under SS, and increased by 20.4, 20.0, 5.4, and 14.2% under R, repectively. However, the treatments reduce the intercellular CO2 concentration under HTS. The SS and R treatments increased the relative water content (RWC) by 11.9 and 6.2%, and the water use efficiency (WUE) by 24.3 and 14.3%, respectively, compared with RT. The SS treatment increased the root length density and soil moisture in the 0-80 cm soil profile, whereas the R treatment increased the root length density and soil moisture in the 0-40 cm soil profile compared with the RT treatment. Compared with 2011, the number of days with temperatures 33°C was more 2 d and the mean day temperature was higher 0.9°C than that in 2012, whereas the plant yield decreased by 2.5, 8.5 and 10.9%, the net photosynthetic rate reduced by 7.5, 10.5 and 18.0%, the RWC reduced by 3.9, 5.6 and 6.2%, and the WUE at leaf level reduced by 1.8, 5.2 and 13.1% in the SS, R and RT treatments, respectively. Both the root length density and the soil moisture also decreased at different levels. The yield, photosynthetic rate, plant water status, root length density, and soil moisture under the SS and R treatments declined less than that under the RT treatment. The results indicated that SS and R can enhance the HTS resistance of spring maize during the filling stage, and led to higher yield by directly improving soil moisture and root growth and indirectly improving plant water status, photosynthesis and grain filling. The study can provide a theoretical basis for improving yield of maize by adjusting soil tillage in the NCP.
    Plant Protection
    Gene Expression Profiling Related to Hyphal Growth in a Temperature- Sensitive Mutant of Magnaporthe oryzae
    LI Xue-song, XU Fei, WANG Hong-kai , LIN Fu-cheng
    2013, 12(12): 2189-2196.  DOI: 10.1016/S2095-3119(13)60503-1
    Abstract ( )   PDF in ScienceDirect  
    The rice blast, caused by fungus Magnaporthe oryzae, is a major constraint to the world food security. Hyphal growth is the foundation of fungal development and proliferation of fungi. To investigate genes involved in hyphal growth of this fungus, digital gene expression tag profiling was used to compare a previously generated temperature-sensitive mutant which defect at hyphae growth and reduction on pathogenicity, with its related wildtype strain. 416 genes were detected as differential expression, 178 of which were specifically expressed in Guy-11 but down-regulated expression in the mutant. Functional classification analysis revealed the phenotype mutation may be mainly caused by a defection in translational and vacuolerelated processes. The results and the protocol used will improve our knowledge on morphogenesis and promote the further study on M. oryzae pathogenesis.
    Genetic Analysis and Molecular Mapping of an All-Stage Stripe Rust Resistance Gene in Triticum aestivum-Haynaldia villosa Translocation Line V3
    HOU Lu, MA Dong-fang, HU Mao-lin, HE Miao-miao, LU Yan , JING Jin-xue
    2013, 12(12): 2197-2208.  DOI: 10.1016/S2095-3119(13)60293-2
    Abstract ( )   PDF in ScienceDirect  
    Triticum aestivum-Hayaldia villosa translocation line V3 has shown effective all-stage resistance to the seven dominant pathotypes of Puccinia striiforms f. sp. tritici prevalent in China. To elucidate the genetic basis of the resistance, the segregating populations were developed from the cross between V3 and susceptible genotype Mingxian 169, seedlings of the parents and F2 progeny were tested with six prevalent pathotypes, including CYR29, CYR31, CYR32-6, CYR33, Sun11-4, and Sun11-11, F1 plants and F3 lines were also inoculated with Sun11-11 to confirm the result further. The genetic studied results showed that the resistance of V3 against CYR29 was conferred by two dominant genes, independently, one dominant gene and one recessive gene conferring independently or a single dominant gene to confer resistance to CYR31, two complementary dominant genes conferring resistance to both CYR32-6 and Sun11-4, two independently dominant genes or three dominant genes (two of the genes show cumulative effect) conferring resistance to CYR33, a single dominant gene for resistance to Sun11-11. Resistance gene analog polymorphism (RGAP) and simple-sequence repeat (SSR) techniques were used to identify molecular markers linked to the single dominant gene (temporarily designated as YrV3) for resistance to Sun11-11. A linkage map of 2 RGAP and 7 SSR markers was constructed for the dominant gene using data from 221 F2 plants and their derived F2:3 lines tested with Sun11-11 in the greenhouse. Amplification of the complete set of nulli-tetrasomic lines of Chinese Spring with a RGAP marker RG1 mapped the gene on the chromosome 1B, and then the linked 7 SSR markers located this gene on the long arm of chromosome 1B. The linkage map spanned a genetic distance of 25.0 cM, the SSR markers Xgwm124 and Xcfa2147 closely linked to YrV3 with genetic distances of 3.0 and 3.8 cM, respectively. Based on the linkage map, it concluded that the resistance gene YrV3 was located on chromosome arm 1BL. Given chromosomal location, the reaction patterns and pedigree analysis, YrV3 should be a novel gene for resistance to stripe rust in wheat. These closely linked markers should be useful in stacking genes from different sources for wheat breeding and diversification of resistance genes against stripe rust.
    Stk2, a Mitogen-Activated Protein Kinase from Setosphaeria turcica, Specifically Complements the Functions of the Fus3 and Kss1 of Saccharomyces cerevisiae in Filamentation, Invasive Growth, and Mating Behavior
    GU Shou-qin, YANG Yang, LI Po, ZHANG Chang-zhi, FAN Yu, ZHANG Xiao-yu, TIAN Lan
    2013, 12(12): 2209-2216.  DOI: 10.1016/S2095-3119(13)60296-8
    Abstract ( )   PDF in ScienceDirect  
    Setosphaeria turcica, an essential phytopathogenic fungus, is the primary cause of serious yield losses in corn; however,
    its pathogenic mechanism is poorly understood. We cloned STK2, a newly discovered mitogen-activated protein kinase gene with a deduced amino acid sequence that is 96% identical to MAK2 from Phaeosphaeria nodorum, 56% identical to
    KSS1 and 57% identical to FUS3 from Saccharomyces cerevisiae. To deduce Stk2 function in S. turcica and to identify the
    genetic relationship between STK2 and KSS1/FUS3 from S. cerevisiae, a restructured vector containing the open reading
    frame of STK2 was transformed into a fus3/kss1 double deletion mutant of S. cerevisiae. The results show that the STK2
    complementary strain clearly formed pseudohyphae and ascospores, and the strain grew on the surface of the medium after
    rinsing with sterile water and the characteristics of the complementary strain was the same as the wild-type strain. Moreover,
    STK2 complemented the function of KSS1 in filamentation and invasive growth, as well as the mating behavior of FUS3 in
    S. cerevisiae, however, its exact functions in S. turcica will be studied in the future research.
    Resistance to the Whitefly Aleurotrachelus socialis (Hemiptera: Aleyrodidae) and SSR Marker Identifi cation in Advanced Populations of the Hybrid Manihot esculenta subsp. Manihot fl abellifolia
    Arturo Carabalí, James Montoya-Lerma, Anthony C Belloti, Martin Fregene , Gerardo
    2013, 12(12): 2217-2228.  DOI: 10.1016/S2095-3119(13)60661-9
    Abstract ( )   PDF in ScienceDirect  
    Genes resistant to Aleurotrachelus socialis were transferred to the F1 from the interspecifi c hybrid wild species of Manihot fl abellifolia to M. esculenta and two advanced generations of backcrosses (BC1 and BC2). We characterized the resistance of A. socialis transferred to BC2 parents (CW67-160, CW67-130, CW67-44), MTAI-8 (BC1), resistant (CMB9B-73) and susceptible (CMB9B-104) genotypes from contrasting pools, and resistant (MEcu-72) and susceptible (CMC-40) genotypes. Whitefl y demography and biology were evaluated. SSR molecular markers associated with a phenotypic response of plant resistance were detected in segregating populations (BC2). Results showed that although female survival time was similar on all hosts, the lowest averages of longevity, fecundity and oviposition rate were observed in the resistant control MEcu- 72, only being signifi cantly similar to the parent CW67-130. When the BC1 and BC2 populations were compared, it was found that A. socialis fecundity was eight times lower on CMB9B-73 progeny than on CW67-130, expressing the highest levels of resistance to the whitefl y. Ten genotypes of CMB9A and CMB9B family had the best segregation. A total of 486 microsatellite primers were evaluated using bulked segregant analysis (BSA), 11 showed polymorphism between the contrasting pools and only one showed signifi cant differences between resistant and susceptible individuals. In conclusion, fecundity was the parameter that impacted most on the intrinsic rate of A. socialis population growth.
    Animal Science · Veterinary Science
    Yeast-Derived β-1,3-Glucan Substrate Significantly Increased the Diversity of Methanogens During In vitro Fermentation of Porcine Colonic Digesta
    LUO Yu-heng, LI Hua, LUO Jun-qiu , ZHANG Ke-ying
    2013, 12(12): 2229-2234.  DOI: 10.1016/S2095-3119(13)60381-0
    Abstract ( )   PDF in ScienceDirect  
    The β-1,3-glucan from yeast has been extensively examined for its immuno-enhancing effects in animals. However, investigation on the relationship among β-glucan, gut microbiota and immune-modulating effects remains limited particularly in pigs. Considering the critical roles of gut methanogens in the microbial fermentation, energy metabolism and disease resistance, we investigated the phylogenetic diversity of methanogens from fermented cultures of porcine colonic digesta with (G) or without (N) yeast β-glucan based on sequences of the archaeal 16S rRNA gene. A total of 145 sequences in the G library were assigned into 8 operational taxonomic units (OTUs) with the majority of sequences (114/145) related to strains Methanobrevibacter millerae or Methanobrevibacter gottschalkii with high identities ranging from 97.9 to 98.6%, followed by 23 sequences to Methanobrevibacter ruminantium, 2 sequences to Methanobrevibacter smithii and one sequence to Methanobrevibacter wolinii. The 142 sequences in the N library were assigned to 2 OTUs with most sequences (127/142) related to strains M. millerae or M. gottschalkii with sequence identities ranging from 97.9 to 98.5%, and 15 sequences related to M. gottschalkii with 97.9% identity. Shannon diversity index showed that the G library exhibited significantly higher archaeal diversity (P<0.05) and Libshuff analysis indicated the differences in the community structure between the two libraries were significant (P<0.0001). In conclusion, the current study provides evidence that addition of yeast β-glucan significantly increased the diversity of methanogens in in vitro fermented porcine colonic digesta.
    Effect of Swim-Up and Percoll Treatment on Sperm Quality and In vitro Embryo Development in Yak
    LIU Ben, CUI Yan , YU Si-jiu
    2013, 12(12): 2235-2242.  DOI: 10.1016/S2095-3119(13)60378-0
    Abstract ( )   PDF in ScienceDirect  
    This study was designed to determine the effect of different sperm preparation treatments on yak sperm quality and in vitro embryo development. Frozen-thawed semen samples were treated using swim-up or percoll gradient centrifugation methods. Sperm concentration, progressive motility, recovery of motile sperm, membrane integrity, acrosome and chromatin integrity were scored and compared in recovered samples and controls. In addition, the effects of two sperm separation treatments on embryos capable of cleavage and in vitro development to the blastocyst stage were evaluated. Swim-up separated sperm showed a higher motility, while the concentration of spermatozoa recovered and percent recovery of motile sperm were higher with percoll gradient centrifugation separation. According to the optical and electron microscopies, swim-up produced higher percentage of sperm with intact plasma membrane and acrosome than percoll gradient centrifugation separation. However, there was no difference in the percentage of sperm with intact chromatin between two treatment groups. Cell numbers in the blastocysts of two groups were not different. The blastocyst rate was similar in both groups, whereas cleavage rate was higher when swim-up was used.
    Levels of Germinable Seed in Topsoil and Yak Dung on an Alpine Meadow on the North-East Qinghai-Tibetan Plateau
    YU Xiao-jun, XU Chang-lin, WANG Fang, SHANG Zhan-huan , LONG Rui-jun
    2013, 12(12): 2243-2249.  DOI: 10.1016/S2095-3119(13)60652-8
    Abstract ( )   PDF in ScienceDirect  
    In order to clarify the interactive mechanism between grazing yak and alpine meadow on the Qinghai-Tibetan Plateau, our study assessed seed density (by species) in the topsoil of alpine meadow with different grazing intensities in the Tianzhu area, north-eastern margins of the Qinghai-Tibetan Plateau and their rates of occurrence in yak dung. Seed density in the topsoil of the lightly grazed, moderately grazed, heavily grazed and extremely grazed alpine meadows in November, 2010 were 1 551, 1 692, 2 660 and 1 830 grains m-2, while in the same meadows in April, 2011 densities were 1 530, 2 404, 2 530 and 2 692 grains m-2, respectively. In the cold season pasture, mean seed density in yak dung from November to April in the lightly grazed, moderately grazed, heavily grazed and extremely grazed sites were 121, 127, 187, and 120 grains kg-1 of dry yak dung. The proportion of total seed numbers in yak dung to soil seed bank in lightly grazed, moderately grazed, heavily grazed and extremely grazed alpine meadow was 1.40, 2.62, 0.69, and 0.90%. 12 species out of the 47 were not found in topsoil but were found in yak dung, 10 species out of 45 were not found in yak dung but were found in the topsoil. Endozoochorous dispersal by yaks is therefore very important for soil seed bank and plant biodiversity and population dynamics in alpine meadows.
    Soil & Fertilization · Irrigation · Agro-Ecology & Environment
    Changes in Soil Hot-Water Extractable C, N and P Fractions During Vegetative Restoration in Zhifanggou Watershed on the Loess Plateau
    XUE Sha, LI Peng, LIU Guo-bin, LI Zhan-bin, ZHANG Chao
    2013, 12(12): 2250-2259.  DOI: 10.1016/S2095-3119(13)60527-4
    Abstract ( )   PDF in ScienceDirect  
    The study was conducted in Zhifanggou Watershed, Shaanxi Province, China, to evaluate the effect of different vegetation types on hot-water extractable C, N and P fractions, with the aim to determine whether hot-water extractable fractions could be used as indicators of soil quality change in Loess Plateau. The six vegetation types established in 1975 were (i) Robinia pseudoacacia L., (ii) Caragana korshinkii Kom., (iii) Pinus tabulaeformis Carr., (iv) P. tabulaeformis-Amorpha fruticosa L., (v) R. pseudoacacia-A. fruticosa, and (vi) grassland. A cropped hillslope plot and a Platycladus orientalis L. native forest plot were used as references. The results indicated that the conversion of native forest to cropland resulted in a significant decline in the hot-water extractable C, N and P fractions. Hot-water extractable C, N, and P increased when cultivated land was revegetated, but after 30 years the amount of hot-water extractable C, N, and P in revegetated fields was still much lower compared to native forest. Hot-water extractable fractions increased more under mixed-forest than under pure-forest stands. Furthermore, there was a significant correlation between the hot-water extractable fractions and soil chemical and microbiological properties. The results showed that hot-water extractable fractions could be used as indicators of soil quality change on the Loess Plateau.
    Variation Characteristics of Hydrothermal Resources Effectiveness Under the Background of Climate Change in Southern Rice Production Area of China
    YE Qing, YANG Xiao-guang, DAI Shu-wei, LI Yong , GUO Jian-ping
    2013, 12(12): 2260-2279.  DOI: 10.1016/S2095-3119(13)60403-7
    Abstract ( )   PDF in ScienceDirect  
    The spatiotemporal characteristics of hydrothermal resources in southern rice production area of China have changed under the background of climate change, and this change would affect the effectiveness of hydrothermal resources during local rice growing period. According to the cropping system subdivision in southern rice production area of China during 1980s, this study used climate data from 254 meteorological stations and phonological data from 168 agricultural observation stations in the south of China, and adopted 6 international evaluation indices about the effectiveness of hydrothermal resources to analyze the temporal and spatial characteristics of hydrothermal resources during the growing period of single cropping rice system and double cropping rice system for 16 planting zones in the whole study area. The results showed that: in southern rice production area of China, the effectiveness of thermal resources of single cropping rice area (SCRA) was less than that of double cropping rice area (DCRA), whereas the effectiveness of thermal resources of both SARA and DCRA showed a decreasing trend. The index value of effective precipitation satisfaction of SCRA was higher than that of DCRA, nevertheless the index value of effective precipitation satisfaction of both SCRA and DCRA showed a decreasing trend. There was a significant linear relationship between effective thermal resource and water demand, likely water demand increased by 18 mm with every 100°C d increase of effective heat. Effective precipitation satisfaction index (EPSI) showed a negative correlation with effective heat, yet showed a positive correlation with effective precipitation. EPSI reduced by 1% when effective heat resource increased by 125°C d. This study could provide insights for policy makers, land managers or farmers to improve water and heat resource uses and rationally arrange rice production activities under global climate change condition.
    Spatiotemporal Characteristics of Reference Evapotranspiration and Its Sensitivity Coefficients to Climate Factors in Huang-Huai-Hai Plain, China
    YANG Jian-ying, LIU Qin, MEI Xu-rong, YAN Chang-rong, JU Hui, XU Jian-wen
    2013, 12(12): 2280-2291.  DOI: 10.1016/S2095-3119(13)60561-4
    Abstract ( )   PDF in ScienceDirect  
    Climate change will have important implications in water shore regions, such as Huang-Huai-Hai (3H) plain, where expected warmer and drier conditions might augment crop water demand. Sensitivity analysis is important in understanding the relative importance of climatic variables to the variation in reference evapotranspiration (ET0). In this study, the 51-yr ET0 during winter wheat and summer maize growing season were calculated from a data set of daily climate variables in 40 meteorological stations. Sensitivity maps for key climate variables were estimated according to Kriging method and the spatial pattern of sensitivity coefficients for these key variables was plotted. In addition, the slopes of the linear regression lines for sensitivity coefficients were obtained. Results showed that ET0 during winter wheat growing season accounted for the largest proportion of annual ET0, due to its long phenological days, while ET0 was detected to decrease significantly with the magnitude of 0.5 mm yr-1 in summer maize growing season. Solar radiation is considered to be the most sensitive and primarily controlling variable for negative trend in ET0 for summer maize season, and higher sensitive coefficient value of ET0 to solar radiation and temperature were detected in east part and southwest part of 3H plain respectively. Relative humidity was demonstrated as the most sensitive factor for ET0 in winter wheat growing season and declining relativity humidity also primarily controlled a negative trend in ET0, furthermore the sensitivity coefficient to relative humidity increased from west to southeast. The eight sensitivity centrals were all found located in Shandong Province. These ET0 along with its sensitivity maps under winter wheat-summer maize rotation system can be applied to predict the agricultural water demand and will assist water resources planning and management for this region.
    Agricultural Economics And Management
    Prediction Model of Weekly Retail Price for Eggs Based on Chaotic Neural Network
    LI Zhe-min, CUI Li-guo, XU Shi-wei, WENG Ling-yun, DONG Xiao-xia, LI Gan-qiong , YU Hai-peng
    2013, 12(12): 2292-2299.  DOI: 10.1016/S2095-3119(13)60610-3
    Abstract ( )   PDF in ScienceDirect  
    This paper establishes a short-term prediction model of weekly retail prices for eggs based on chaotic neural network with the weekly retail prices of eggs from January 2008 to December 2012 in China. In the process of determining the structure of the chaotic neural network, the number of input layer nodes of the network is calculated by reconstructing phase space and computing its saturated embedding dimension, and then the number of hidden layer nodes is estimated by trial and error. Finally, this model is applied to predict the retail prices of eggs and compared with ARIMA. The result shows that the chaotic neural network has better nonlinear fitting ability and higher precision in the prediction of weekly retail price of eggs. The empirical result also shows that the chaotic neural network can be widely used in the field of short-term prediction of agricultural prices.
    Revenue Sharing in Dairy Industry Supply Chain - A Case Study of Hohhot, China
    QIAN Gui-xia12, ZHANG Yi-pin1, WU Jian-guo23 and PAN Yue-hong4
    2013, 12(12): 2300-2309.  DOI: 10.1016/S2095-3119(13)60585-7
    Abstract ( )   PDF in ScienceDirect  
    Dairy industry has become an increasingly important enterprise in China as people’s dietary preferences and composition have changed dramatically with rapid economic development in the past several decades. A number of problems, however, exist in China’s relatively young dairy industry, including the imbalanced allocation of profits throughout the dairy supply chain. One of the root causes of the melamine infant powered milk scandal in 2008 was the unfair profit allocation mechanism in dairy supply chain. The revenue sharing contract approach has proven to be effective in generating market shares and total profits. In this study, we apply the three-stage revenue sharing contract model of Giannoccaro and Pontrandolfo (2004) in an analysis of dairy supply chain to explore its problems in profit allocation and possible solutions to them. The analysis was conducted by a case study of Hohhot, often called as “milk capital of China”. Our results show that the current profit distribution in the dairy supply chain is not balanced: the supermarket’s profit>farmer’s profit>manufacturer’s profit. Under the revenue sharing contract setting, the dairy industry’s total profit increased by 12.49%. By exploring different parameters in the revenue sharing contract model, we have found that a win-win situation can be created among all the members of the supply chain. In dairy supply chain, the ratio of the revenue reserved for the supermarket itself is equal or greater than 47% and the ratio of the revenue reserved for the manufacturer itself is between 46.4 and 50.2%. The values of the parameters that generate a sustainable or win-win situation are related to the bargaining position in the dairy supply chain. The revenue sharing contract has proven to be effective and desirable by all the dairy chain partners in dairy supply chain. The results of this study provide relevant information for improving the dairy supply chain structure and the revenue sharing contract model can be applied to other industries, sectors and regions.
    Assessment of Flood Catastrophe Risk for Grain Production at the Provincial Scale in China Based on the BMM Method
    XU Lei, ZHANG Qiao, ZHOU Ai-lian, HUO Ran
    2013, 12(12): 2310-2320.  DOI: 10.1016/S2095-3119(13)60587-0
    Abstract ( )   PDF in ScienceDirect  
    Flood catastrophe risk assessment is imperative for the steady development of agriculture under the context of global climate change, and meanwhile, it is an urgent scientific issue need to be solved in agricultural risk assessment discipline. This paper developed the methodology of flood catastrophe risk assessment, which can be shown as the standard process of crop loss calculation, Monte Carlo simulation, the generalized extreme value distribution (GEV) fitting, and risk evaluation. Data on crop loss were collected based on hectares covered by natural disasters, hectares affected by natural disasters, and hectares destroyed by natural disasters using the standard equation. Monte Carlo simulation based on appropriate distribution was used to expand sample size to overcome the insufficiency of crop loss data. Block maxima model (BMM) approach based on the extreme value theory was for modeling the generalized extreme value distribution (GEV) of flood catastrophe loss, and then flood catastrophe risk at the provincial scale in China was calculated. The Type III Extreme distribution (Weibull) has a weighted advantage of modeling flood catastrophe risk for grain production. The impact of flood catastrophe to grain production in China was significantly serious, and high or very high risk of flood catastrophe mainly concentrates on the central and eastern regions of China. Given the scenario of suffering once-in-a-century flood disaster, for majority of the major-producing provinces, the probability of 10% reduction of grain output is more than 90%. Especially, the probabilities of more than 15% decline in grain production reach up to 99.99, 99.86, 99.69, and 91.60% respectively in Anhui, Jilin, Liaoning, and Heilongjiang. Flood catastrophe assessment can provide multifaceted information about flood catastrophe risk that can help to guide management of flood catastrophe.
    Short Communication
    A Seroprevalence Survey of Maedi-Visna Among Twenty-Four Ovine Floks from Twelve Regions of China
    ZHANG Ke-shan, HE Ji-jun, LIU Yong-jie, SHANG You-jun , LIU Xiang-tao
    2013, 12(12): 2321-2323.  DOI: 10.1016/S2095-3119(13)60380-9
    Abstract ( )   PDF in ScienceDirect  
    Maedi-visna virus (MVV) is an ovine lentivirus that is widespread in many countries worldwide. Both clinical and subclinical MVV infections cause substantial economic losses. MVV infection in live sheep is usually diagnosed serologically, with antibody-positive sheep being regarded as infected. There have been few reports of maedi-visna in China, with no detailed epidemic analysis of MVV infection in ovine herds. In order to investigate the seroprevalence and spatial distribution of maedi-visna among ovine flocks in China, a total of 672 serum samples were collected from different ovine flocks in 12 regions (provinces, autonomous regions or municipalities) of China in 2011, and serum antibody levels were determined using a commercial ELISA Kit. This study represents the first investigation of the seroepidemiology of maedi-visna in China, indicating a circulation of MMV among sheep.