湖北省小麦适宜播期的叶龄积温法确定

为探明气候变暖背景下湖北省各地小麦适宜播期,同时为鄂北地区小麦亩产千斤提供理论支撑,本研究对2008~2012年湖北省郧西等10个地区的气象数据进行了分析,依据在前期研究基础上提出的湖北省小麦主导品种郑麦9023的叶热间距,运用叶龄积温法推算得出郧西等10个地区的小麦适宜播期。生产上各地可根据此次研究结果,结合当地气象预报、土壤墒情以及小麦品种特性等适当调整小麦播期,确保小麦壮苗越冬、高产稳产。     

烤烟套种蚕豆对烟叶和蚕豆品质的影响

为确定烤烟套种免耕鲜食蚕豆的最佳播种期,采用随机区组试验,研究烟株封顶后上部烟留叶8片、5片、3片和顶叶全部采收后播种蚕豆对免耕套种鲜食蚕豆和烟叶产质量的影响。结果表明：烤烟套种免耕鲜食蚕豆模式比烤烟采收后单一种植蚕豆（CK）中上等烟比例提高0．56％～1．58％,产量提高0．54％～0．63％,产值提高1．38％～2．01％;可提高总糖和还原糖含量,降低氮和烟碱含量,增加钾和施木克值,协调烟叶内在品质;增加收入293．18～454．03元／667m2。可提高蚕豆的蛋白质、钙和硒的含量,分别比 CK 增加0．41％～0．56％、11．53％～34．61％和4．93％～11．11％;降低单宁的含量,比 CK 降低18．18％～36．36％。上部烟留叶5片的处理对提高烟叶和蚕豆的品质效果最佳。     

不同播期、密度和肥料对菜用板蓝根产量及品质的影响

为探索菜用板蓝根在毕节地区的优质高产栽培措施,通过田间试验研究菜用板蓝根不同播期、密度和氮钾肥施用量对产量及品质的影响。结果表明,在毕节地区,菜用板蓝根适宜播期为4月30日左右,种植密度为50．025～66．70万株/hm2,钾肥施用量为150～300 kg/hm2,氮肥施用量为778 kg/hm2左右,在此栽培条件下,产量可达73947．96～76749．35 kg/hm2,且品质较好,蛋白质、脂肪、水溶性糖及维生素含量较高,粗纤维含量较低。     

基于单片段代换系的水稻抽穗期QTL上位性研究

【目的】探索水稻抽穗期的遗传机制.【方法】以华粳籼74的8个单片段代换系为材料,构建了7个聚合了双QTL的次级F2作图群体,并通过分子标记的选择区分出每个群体的9种基因型以估算水稻抽穗期QTL的各类上位性分量.【结果和结论】除QTL HD3/HD8间的上位性互作不显著外,其他QTL对均存在显著的上位性效应,占85.7%;在检测的28个不同类型的上位性效应中,有60.7%的估计值达到5%或1%的显著水平,其中加加、加显或显加、显显上位性分别占71.3%、42.8%、85.6%.研究结果进一步证实了上位性作用在数量性状遗传体系中的普遍性和重要性,并为水稻抽穗期的分子聚合育种提供了依据和材料.     

我国森林资源采伐消耗特点分析

通过第八次森林资源清查成果分类汇总,分析我国森林资源采伐消耗的现状、结构及区域分布特点,以历次森林资源清查结果分析我国森林资源采伐消耗动态变化趋势及特点,提出了加强林木采伐管理、科学经营森林、提高木材供给能力的对策、措施和建议。     

地力水平和播期对冬小麦籽粒产量及氮素利用率的影响

以泰农18为试材,在播种密度(基本苗)405.0万株/hm2条件下,研究两个不同地力水平和适度早播(10月1日)、适播(10月8日)和适度晚播(10月15日)对冬小麦籽粒产量和氮素利用率的影响。结果表明:高地力水平下小麦籽粒产量较高但氮素利用率偏低;同地力条件下,适当推迟播期,通过协调单位面积穗数和穗粒数,仍可维持与早播和适播条件下相当水平的籽粒产量;虽然推迟播期降低冬小麦氮素吸收效率,但可提高氮素利用效率,两者互补,所以适当推迟播期氮素利用率仍可维持与早播和适播相当的水平。因此,在不同地力水平下,适当推迟播期可以调控冬小麦冬前群体免受冷害和寒害的影响,维持较高的籽粒产量和氮素利用率。     

花优14作双季晚稻在鄱阳湖平原种植试验示范表现及高效应用思考

为明确杂交晚粳花优14在江西省适宜播种期和栽插苗数,开展了不同播种期和栽插苗数试验。结果表明:花优14在鄱阳湖平原作双季晚稻手工栽插,适宜播种期为6月中、下旬,秧龄25~30 d,每丛插3本或3本以上有利获取高产,最后提出了花优14高效应用思考。     

适应机械化收获的田间油菜植株特性研究

油菜机械化收获过程出现的高损失率制约了油菜生产的发展,单纯从农机方面进行研究难以解决。该文从农机农艺相结合出发,对田间油菜植株特性进行测试研究。测试大田植株整体表现特性及不同密度下植株茎秆物理特性的田间表现,并在不同成熟度和催熟剂喷施情形下对油菜角果拉断力进行测试,获得了田间植株特性基础数据。结果表明适宜的种植密度有利于机械化收获作业,催熟剂的喷施对机收作业性能影响不大。研究获得了直播油菜的田间植株表现特征,同时为油菜机收配套农艺要求提供理论研究基础和参考依据。     

Range fidelity: The missing link between caribou decline and habitat alteration?

Conservation of forest-dwelling caribou (Rangifer tarandus caribou) is of great concern across most of its range. Anthropogenic disturbances, primarily logging activities, have been identified as the most important cause of caribou decline, although the mechanisms underlying this decline are not fully understood. Caribou commonly display fidelity to calving sites or seasonal ranges, but the potential role of this life-history trait has been largely overlooked in research and conservation planning. This is surprising because sites and ranges with high inter-annual use should have high conservation value. We investigated the relationship between habitat disturbances and home-range fidelity of forest-dwelling caribou across three study sites in Québec, Canada, using a broad range of natural and anthropogenic disturbances. Between 2004 and 2007, we tracked 47 adult female caribou using GPS collars. Home-range fidelity varied between seasons, being higher during calving and summer, and lower during winter. Caribou reduced fidelity following natural and anthropogenic disturbances, the latter having a stronger negative influence. Anthropogenic disturbances had a strong negative impact on home-range fidelity during annual, summer and winter periods, whereas natural disturbance was the dominant factor during calving. Despite this negative influence on fidelity, caribou tended to demonstrate range fidelity even in study sites most impacted by human activities. Habitat disturbances could produce two possible outcomes for caribou conservation: (1) a trend for females to reduce home-range fidelity which could translate into lower calf and female caribou survival through reduced familiarity with food distribution, escape cover and predation risk and (2) a global tendency to maintain range fidelity even in a drastically modified landscape which could turn into an ecological trap, particularly for calves when predation risk increases due to increased black bear density in early successional forests. Taking range fidelity behavior into consideration during forest management planning could direct conservation efforts toward the best available sites and therefore facilitate caribou persistence in managed landscapes.     

Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River,Canada–USA

Maltais E, Daigle G, Colbeck G, Dodson JJ. Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River, Canada–USA.
Ecology of Freshwater Fish 2010: 19: 586–594. © 2010 John Wiley & Sons A/S Abstract – The most northerly population of American shad (Alosa sapidissima), located in the St. Lawrence River, is considered vulnerable because of low population abundance and limited spawning habitat located at the upstream extent of the population’s anadromous migration. Here, we aimed to establish the temporal and spatial extent of spawning based on a novel hatch‐date analysis of juveniles. Spawning activity lasted from early May to early July. We found that juveniles captured downstream during the summer hatched later in the year than those captured further upstream. As a result, younger juveniles were distributed somewhat further downstream. In addition, we found significant multimodality in hatch‐date distributions at midstream and downstream sampling stations. Together, these results provide evidence that the 2‐month spawning period involved numerous spawning events that progressed in a downstream direction as the season advanced, rather than being restricted to upstream sites over the spawning season.