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湖南省安乡县2008—2013年的棉花生产，有4年遭受了较大的自然灾害。特提出“调整农作物结构布局、开展农田水利基本建设、发展种棉大户等新型生产经营体、实行棉花生产农机农艺结合、推广棉花间作栽培、普及棉花避灾减灾栽培技术和大力发展农业保险”等7项棉花防灾减灾措施。 相似文献
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2004年,某种业企业生产的玉米杂交种,农民种植后出现大面积的空秆、秃尖现象,导致大面积减产,给农民带来严重损失：2005年,许多杂交水稻种子应用在生产后,大面积感稻瘟病,造成严重减产;2007年,某上市种子企业的杂交玉米新品种在川中、川东、川北大面积出现严重结实不良现象：2008年重庆某公司的水稻杂交种出现大面积感稻瘟病,给农户带来严重损失。 相似文献
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年我国玉米出口量超过万t 据海关统计 年月我国玉米出口量为.万t 这就使得全年玉米出口量达到了.万t。这一数量比和年玉米出口总和还多了.万t。 年我国玉米出口大幅度增长 主要是由于实行了积极的出口政策。在国内供给不断增加 市场供求出现了严重的不平衡的情况下 千方百计扩大出口 是对国内粮食市场进行宏观调控的重要措施。 对玉米实行积极的出口政策 可谓一箭双雕 一是在一定程度上缓解了国内的供给压力 减少了国有粮食企业的玉米库存；二是相对减少了国内玉米流 《玉米科学》2001,9(1):36
2000年我国玉米出口量超过1 000万t
据海关统计，2000年12月我国玉米出口量为99.3万t，这就使得全年玉米出口量达到了1 046.557万t。这一数量比1998和1999年玉米出口总和还多了147.4万t。
2000年我国玉米出口大幅度增长，主要是由于实行了积极的出口政策。在国内供给不断增加，市场供求出现了严重的不平衡的情况下，千方百计扩大出口，是对国内粮食市场进行宏观调控的重要措施。
对玉米实行积极的出口政策，可谓一箭双雕，一是在一定程度上缓解了国内的供给压力，减少了国有粮食企业的玉米库存；二是相对减少了国内玉米流通量，拉动了连续低迷的玉米价格的合理回升。
2000年玉米因旱害减产，且减产幅度很大，但当年供给量的减少，并没有能改变总供给大于总需求的基本格局。因此，在减产已成定局的情况下，我国的玉米出口的步伐并没有减慢。入世在即，充分利用最后一段时间，通过出口补贴的手段，尽可能多出口一些玉米，对于平衡国内市场，减少国内的库存压力，具有积极的意义。
—网上信息— 相似文献
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玉米大斑病、小斑病和丝黑穗病是云南昭通地区玉米生产上的主要病害，尤以阴湿冷凉山区发病较重，一般减产１０％左右，重病时减产３０％以上，严重地影响玉米产量和品质。解决玉米病害危害的根本措施是选育推广抗多种病害的品种。１９７４年昭通地区农业科学研究所玉米组... 相似文献
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Systemic and asymptomatic Neotyphodium fungal endophytes infect numerous species of the Poaceae. The frequencies of Neotyphodium endophyte infection in Finland were investigated among and within seven Nordic cultivars of meadow fescue, Schedonorus pratensis (Huds.) P. Beauv., which is a widely grown pasture and forage grass species in Scandinavia. The cultivars were Kasper, Salten, Antti, Fure, Ilmari, Inkeri and Kalevi. Frequencies of infection of cultivars varied from endophyte-free cultivar Fure to highly infected cultivar Inkeri [mean (standard deviation of mean) of 0·95 (0·023)]. Mean frequencies of infection of three cultivars remained lower than 0·10, and two of the cultivars, Kasper and Salten, were intermediately infected. In most of the cultivars, frequencies of infection varied only slightly among seed lots. In cultivar Kasper, however, the frequency of endophyte infection was highly variable (0–0·96) among the 45 seed lots examined. The relative importance of cultivar, seed lot and infection by Neotyphodium endophyte to the aphid Rhopalosiphum padi L. was studied experimentally, using both endophyte-free and endophyte-infected plants of four seed lots of the two intermediately infected cultivars. Endophyte infection increased plant resistance to R. padi , overriding the influences of seed lot and cultivar. It is proposed that variation caused by endophyte infections in cultivars of meadow fescue should be taken into account in assessing plant breeding programmes in Europe. 相似文献
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Quynh-Hoa Pham Xuan-An Tran Thi-Nha-Trang Nguyen Thi-Thuy-Anh Tran Hai-Yen Hoang Thi-Hong-Van Nguyen Thi-Hanh Tang Thi-Phuc Do 《水稻科学》2016,23(6):334
Rice(Oryza sativa) is sensitive to salinity, but the salt tolerance level differs among cultivars, which might result from natural variations in the genes that are responsible for salt tolerance. High-affinity potassium transporter(HKTs) has been proven to be involved in salt tolerance in plants. Therefore, we screened for natural nucleotide polymorphism in the coding sequence of Os HKT1, which encodes the HKT protein in eight Vietnamese rice cultivars differing in salt tolerance level. In total, seven nucleotide substitutions in coding sequence of Os HKT1 were found, including two non-synonymous and five synonymous substitutions. Further analysis revealed that these two non-synonymous nucleotide substitutions(G50T and T1209A) caused changes in amino acids(Gly17Val and Asp403Glu) at signal peptide and the loop of the sixth transmembrane domain, respectively. To assess the potential effect of these substitutions on the protein function, the 3D structure of HKT protein variants was modelled by using PHYRE2 webserver. The results showed that no difference was observed when compared those predicted 3D structure of HKT protein variants with each other. In addition, the codon bias of synonymous substitutions cannot clearly show correlation with salt tolerance level. It might be interesting to further investigate the functional roles of detected non-synonymous substitutions as it might correlate to salt tolerance in rice. 相似文献
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马铃薯试管苗组织培养及微型薯诱导技术的研究 总被引：9，自引：2，他引：9
通过加入不同浓度的BA、NAA和KT,以探讨外源激素对马铃薯试管苗生理性状的影响,发现低浓度的外源激素较适合用来进行试管苗的增殖。本试验利用香豆素进行微型薯的诱导,结果表明低浓度的香豆素对提高薯重和大薯率有利,而高浓度有利于提高微型薯的结薯数量。 相似文献
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Russell Pressey 《American Journal of Potato Research》1969,46(8):291-297
Freshly harvested potatoes contain low levels of total invertase and high levels of invertase inhibitor. Total invertase increases sharply when potatoes are placed in cold storage, but the inhibitor is not depleted in all varieties. The absence of basal invertase activity in Norchip tubers indicates that an excess of invertase is not required for reducing sugar formation. Analyses of 37 varieties and seedlings after 3 months cold storage revealed that the reducing sugar content is not proportional to the invertase activity. High sugar contents are associated with low inhibitor levels, but low sugars are not necessarily associated with high inhibitor levels. The results indicate that invertase participates in reducing sugar formation, but other factors are responsible for the regulation of starch-sugar conversion in potatoes during cold storage. 相似文献
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Soomro MT Zahir E Mohiuddin S Khan AN Naqvi II 《Pakistan journal of biological sciences: PJBS》2008,11(2):285-289
In present study, Mn, Fe, Zn, Cu, Co, Pb, Cr, Ni and Cd were analyzed by FAAS in green and black tea samples of locally available in the Pakistani market. Na and K were also determined by Flame Photometer. Tea leaves can be the source of mineral components and trace elements, as well as some undesirable substances due to exposure to the environment. Among the metals tested, K was the most abundant one followed by Na, Mn and Fe. Fortunately, toxic heavy metals, Pb and Cd, had the lowest contents in tea samples and also in tea aqueous extracts. Concentration of heavy metals in tea aqueous extract was markedly lower than their total contents except that of K. The solubility of studied metals in tea aqueous extract varied widely and ranged from 0.0-95%. The lowest ranges of solubility were listed for toxic heavy metals Pb and Cd. The possible uptake of metals by the human body from tea aqueous extract has also been determined. The amounts of metals that one may take up through consumption of tea aqueous extract were found to match the acceptable daily intake even taking into account exposure from air, food and drinking water. 相似文献
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1 前 言目前 ,马铃薯脱毒快繁技术已广泛应用于科研与生产中 ,快繁过程中脱毒苗培养基支持体通常采用琼脂或直接采用液体培养。然而这两种培养基存在着诸多问题 ,例如琼脂培养基中的琼脂价格昂贵、成本高 ,而且胶体不利于营养物质的扩散、透气性差 ,导致瓶苗生长不良。因此 ,该实验在本着降低成本的同时 ,又能保证瓶苗正常生长的前提下 ,以蛭石代替琼脂 ,分析其在实际生产中的应用价值。2 材料与方法2 1 材料供试品种为郑薯 6号脱毒苗 ,试验于 2 0 0 2年在郑州市蔬菜研究所马铃薯脱毒实验室内进行。2 2 方法本试验设两个处理 :处理 1… 相似文献
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利用Matlab软件对玉米子粒灌浆过程用Richards方程进行拟合后,通过编程实现灌浆次级特征参数计算,并对不同播期子粒灌浆特征进行分析和探讨。结果表明,在黑龙港地区生态条件下,不同播期玉米各部位子粒灌浆均符合"S"形生长曲线,可用Richards方程很好地拟合。不同播期条件下,早播处理子粒起始势最高,达到灌浆盛期时间最早,平均灌浆速率及最大灌浆速率最大,活跃灌浆期较长,粒重最高。各播期玉米不同部位子粒,穗下部与上部相比,子粒的起始生长势较大,平均灌浆速率较高,达到灌浆高峰期时间较短,粒重较高。 相似文献
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试验以5个生产用马铃薯品种脱毒试管苗为材料,采用组织培养的方法,初步研究了茎切段在正常磷及低磷培养基中生长30 d时幼苗的磷营养效率差异,为筛选出适宜于生产用的磷高效马铃薯品种奠定了基础。试验结果表明,5个马铃薯品种幼苗在正常磷和低磷胁迫下对磷素的吸收和利用能力均存在明显的基因型差异。利用各品种幼苗的磷效率指标(植株干重、鲜重、吸磷量、磷利用效率)的相对指标(低磷处理的结果/正常磷处理的结果×100)进行聚类分析(类平均法)的结果表明,大白和I-1035属于磷高效基因型品种,中农Ⅷ是磷低效基因型品种,凉薯97和疫不加则属于中间类型品种。 相似文献