实行休耕轮作 提高种田效益

<正>泗县地处皖东北,是全国产粮大县,一年两熟制,境内以旱作为主,另有极少部分采取小麦、水稻轮作种植模式。2009年,泗县农机推广站在调研活动中了解到,采取小麦、水稻轮作种田效益一直难以提高,经过与农艺技术人员和农户共同探讨,2010年在泗县耕耘农机专业合作社流转的80亩耕地上探索休耕轮作,取得了较好经济效益,得到了周边群众认可。     

四川肉羊遗传资源现状及保护利用对策

正畜禽遗传资源是生物多样性的重要组成部分,因其具有不可再生性,世界各国都十分重视对它的保护和开发利用。四川肉羊品种资源丰富,地方资源羊肉产品市场价格较高,具有良好的发展潜力和市场前景,是食品消费转型升级和多元化需求的必然选择。肉羊遗传资源保护与利用的关键是要加快发展特色产品,进一步提高羊产品的附加值,充分利用优良资源,提高羊产品核心竞争力。     

Improving Drought Tolerance of Rice by Designed QTL Pyramiding

Drought is the most important factor limiting rice yields in the rainfed areas of Asia. To overcome the problem, we developed a new strategy ＇designed QTL pyramiding＇ to more efficiently develop drought tolerant （DT） rice cultivars. In the first phase of this strategy, we developed large numbers of introgression lines （ILs） in elite backgrounds using backcross （BC） breeding, each of which carries multiple genomic segments for improved DT from a known donor. Then, we genotyped all ILs with SSR markers to track the genomewide pattern of introgression in the DT ILs of 16 BC populations derived from crosses between 2 recipients （IR64 and Teqing） and four different donors. X^2 tests and linkage disequilibrium analyses of introgression in the DT ILs revealed significant frequency shifts at many loci across the genome and non-random associations at the multilocus level as a result of selection for DT in the ILs, which led us to the discovery of putative genetic networks underlying DT in the ILs. The networks each containing all DT loci detected in ILs from a BC population showed some interesting features.     

TILLING and Ecotilling the Plant Kingdom

The modem crop scientist has a large amount of available nucleotide sequence information to identify genes of potential agronomic importance. Using reverse genetic approaches, specific genes can be disrupted, and hypotheses regarding gene function directly tested in vivo. Although a number of reverse genetic methods have been introduced, many are limited in application because they are organism-specific, expensive, transgenic, or only transiently disrupt gene function. However, traditional mutagenesis using chemical mutagens has been widely used as a forward genetics strategy to create many new crop plant varieties at relatively low cost. Mutagens such as ethyl methanesulphonate （EMS） cause stable point mutations and thus produce an allelic series of truncation and missense changes that can provide a range of phenotypes （Greene et al., 2003）. TILLING （targeting induced local lesions IN genomes） is a high-throughput reverse genetic strategy that combines traditional mutagenesis and SNP discovery methods （Colbert et al., 2001; McCallum et al., 2000）. To identify mutations, target regions of-l.5 kb are amplified with fluorescently labeled gene specific primers. Heteroduplexes are then formed between wild-type and mutant strands, mismatches are cleaved by incubation with a single-strand specific nuclease,     

Development of Elongated Uppermost Intemode CMS Lines for Hybrid Rice Breeding in India

Development of cytoplasmic male sterile （CMS） lines with elongated uppermost internode （EUI） trait provides a genetic option to eliminate the use of GA3 in hybrid rice. During the past two decades, extensive work has been carried out on the subject that resulted in identification of several mutants with EUI trait for use in developing cytoplasmic/thermo-sensitive genic male-sterile lines with complete panicle exsertion （Okuno and Kawai, 1978; Rutger and Carnahan, 1981; Shen et al., 1987; Yang et al., 2000; 2002; Gangashetti et al., 2004）. Two recessive genes （eui-1 and eui-2） mapped on chromosome 5 and 10 respectively have so far been reported to control the internode elongation in rice （Librojo and Khush, 1986; Yang et al., 2001; Ma et al., 2004）. Considerable progress has been made in China in exploiting ＇eur gene for development of hybrid rice parental lines （Yang et al., 2000; 2002; Zhang et al., 2002）.     

Mapping QTLs for Yield Stability in Durum Wheat Grown under Different Water Regimes

Among the most important Mediterranean annual crops, durum wheat is widely grown in drought-prone areas. Therefore, improving water-use efficiency （WUE） of durum wheat represents a major breeding goal. IDu-WUE （Improving Durum wheat for Water Use Efficiency and yield stability through physiological and molecular approaches） is a collaborative project among public and private research centres in Italy, Spain and WANA （West Asia and North Africa） countries （Morocco, Tunisia, Syria and Lebanon） funded by the European Union aimed at investigating the genetic variation for WUE and yield stability in durum wheat grown in Mediterranean droughtprone areas. During the first year of the project, a number of morpho-physiological traits （e.g. early vigour, flowering time, leaf rolling, number of fertile tillers, etc.）, WUE, WUE-related traits （e.g. carbon isotope discrimination, canopy temperature, chlorophyll fluorescence, etc.）, yield and its components have been investigated in a RIL population （249 lines） and a collection of ca. 190 durum wheat accessions characterized by a high level of linkage disequilibrium （Maccaferri et al., 2005）,     

Production of transgenic adult plants from clementine mandarin by enhancing cell competence for transformation and regeneration

Genetic transformation of mature trees is difficult because adult tissues are recalcitrant to Agrobacterium tumefaciens infection and transformation and because transgenic mature events are less competent for regeneration. We have shown that reinvigoration allows manipulation of the vegetative phase to increase the potential for transformation and regeneration without loss of competence for flowering and fruiting. To produce transgenic plants from clementine mandarin (Citrus clementina hort. ex Tanaka), we optimized the conditions of the source material both ex vitro and in vitro. Grafting of mature buds on juvenile rootstocks in the spring and preventing multiple bud sprouting by removing all but one bud permitted selection of vigorous first flushes for in vitro culture. Use of additional virulence genes from A. tumefaciens to increase transformation frequency and optimization of culture media and conditions to enhance explant cell competence for T-DNA integration and organogenesis resulted in efficient and reliable transgenic plant production. Transformed regenerants from explants, cultured in media without antibiotics, were identified by a screenable marker (either beta-glucuronidase or green fluorescent protein (GFP)), creating the possibility of generating transgenic clementine plants without antibiotic resistance marker genes. Stable integration of foreign genes was demonstrated by Southern blot analysis, and expression of these foreign genes was confirmed by detection of GFP fluorescence in leaves, floral organs and fruits of the transgenic plants.     

日本复层混交林

本文概述了日本复层混交林的经营历史,主要种类,以及不同林型的复层混交林的经营目的和经济,生态、社会效益,最后就日本复层混交林经营发展尚存在的问题作了简要论述。     

Antibacterial activity of fresh flower heads of Chrysantemum coronarium

The antibacterial activity of the methylene chloride and methanol extracts of Chrysantemum coronarium fresh flower heads was investigated. The methylene chloride extract showed discrete antimicrobial activity.     

湘潭市能源的生态足迹及森林固碳减排效应的分析

生态足迹作为可持续发展定量研究的一种新方法,具有简明而综合的特点。采用生态足迹成分法对湘潭市2003年能源的生态足迹进行了计算,并对湘潭市2003年CO2排放量及森林固碳减排效应进行了分析。结果表明:2003年湘潭市人均能源生态足迹为0.653 hm2,实有人均能源生态足迹为0.077 hm2,人均能源生态足迹赤字为0.576hm2;2003年湘潭市CO2排放量为1 186.42万t,现有森林CO2年吸收量为140.25万t。通过扩大森林面积和提高森林生产力,每年可多吸收74.27万t CO2,实现减排6.26%。