农田野燕麦的危害与大麦田防除技术

1农田野燕麦的发生危害野燕麦（AvenafatuaL．）是我国麦田主要恶生杂草之一，从50年代开始就已不断繁殖、传播和蔓延危害，主要发生危害地以我国西北和东北春麦区；60年代青海、黑龙江等省对野燕麦的生物学特性，危害损失及防除技术等开展了研究工作，推动了该地区的区域防治，在生产中发挥了很大的作用。近十几年来，随着生产调种的频繁，野燕麦东侵南犯，迅速传播蔓延。我省在80年代初只在局部地区零星发生，而90年代已在沿海、徐淮和沿江各大农业区扩展危害，发生面积已达600万亩以上，其中危害面积在150万左右。据1993年盐城市以东台…     

野燕麦对春大麦产量的影响

在英国野燕麦(Avena fatua L.)是谷类作物中危害最重、分布最广的杂草(Elliott等,1979)。作物受野燕麦严重侵害,使产量大幅度降低(Selman,1970;wilson等,1974、1978)。但损失的幅度可能悬殊很大,即使野燕麦密度相差五倍,而损失可能类同(Hoepfner,1969)。     

野燕麦对不同小麦品种产量性状的影响及其经济阈值

为给防除小麦田间恶性杂草野燕麦提供依据,采用添加系列试验和模型拟合的方法研究了野燕麦与小麦的竞争.结果表明,随着田间野燕麦密度的增加,小麦有效穗数、穗粒数和产量逐渐降低,而小麦千粒重的变化趋势不明显.模型拟合结果显示,野燕麦密度与小麦有效穗数和产量间的关系以指数模型(y=beax)较好,与穗粒数间的关系以直线模型(y=ax b)较好,而与小麦产量损失间的关系以对数模型(y=alnx b)最佳.野燕麦对矮秆小麦品种郑麦9023产量性状的影响大于对高秆品种鄂麦35057的影响.根据小麦的经济危害允许水平,通过拟合的野燕麦密度与小麦产量损失的对数模型估算,当小麦品种为鄂麦35057时,野燕麦人工防除的经济阈值为9.04株·m-2,使用6.9%精噁唑禾草灵水乳剂化学防除的经济阈值为3.77株·m-2;而当小麦品种为郑麦9023时,相应的经济阈值分别为5.85株·m-2和3.32株·m-2.不同小麦品种的生长竞争能力存在较大差异,这可能是导致野燕麦与小麦间的竞争发生变化的原因.     

小麦与野燕麦杂交后代品系光合特性的研究

为了研究小麦与野燕麦杂交后代高产的原因,用LI-6400光合作用测定系统测定了小麦与野燕麦杂交后代及其亲本的开花期旗叶净光合速率(Pn)、气孔导度(Cd)、胞间CO2浓度(Ci)和蒸腾速率(Tr),并计算了水分利用效率,用方差分析和相关性分析方法对11个参试材料的光合特性进行了综合评价。结果表明,小麦与野燕麦杂交后代的净光合速率显著高于普通小麦和野燕麦;各品种(系)的气孔导度变化趋势与蒸腾速率变化趋势一致,气孔导度大的一般蒸腾速率也较高;光合速率与气孔导度和蒸腾速率显著相关,与产量正相关,但相关不显著;小麦与野燕麦杂交后代的光合能力高于亲本和普通小麦。     

240g/L收乐通防除马铃薯田野燕麦及对马铃薯安全性评价

野燕麦是马铃薯田的主要杂草之一,人工除草工作量大。本研究的目的是明确240 g/L收乐通EC在青海省马铃薯田防除野燕麦药效、适宜剂量及对作物的安全性。在田间使用了240 g/L收乐通EC制剂量300,450,600 mL/hm2,以108 g/L高效盖草能EC制剂量375 mL/hm2为对照药,设空白对照处理,于马铃薯3~5叶期,野燕麦为3~6叶期兑水300 L/hm2喷雾处理。结果表明,240 g/L收乐通EC是马铃薯田防除野燕麦的优良除草剂,适宜剂量为450 mL/hm2,对野燕麦40 d株防效和鲜重效均达85%以上,对马铃薯安全,增产率达10%以上。     

小麦和大麦基因型对透光和野燕麦生长的影响

为了稳定产量潜力和减少投入,谷类作物育种者筛选出抗病抗虫的性状,从而通过对抑制杂草发育的生长习性的选择,有可能培育出对杂草蔓延耐性增加的品种。我们的目的是,确定小麦和大麦是否在减少行间透光和抑制野燕麦生长的能力上存在差异。依据我们的试验结果,在春小麦、冬小麦和春大麦的内部存在着行间太阳光透过的显著遗传变异,７个被研究的试验圃中有４个的株高与透光呈显著负相关。株高相近而允许透光量不同的６个大麦系和６个春小麦系被用来测验对野燕麦的抑制作用,大麦与野燕麦的竞争能力强于小麦,前者的燕麦生物量和种子产量是后者的一半,大麦系允许透过的光量比小麦的少４３％。野燕麦的生长性状在作物内系间也存在显著的变异。在大麦中,野燕麦生长与透光的高度正相关表明,选系有助于野燕麦的综合管理。     

野燕麦对油菜生长的影响及其经济阈值

采用添加系列试验和模型拟合的方法研究了不同野燕麦密度下油菜各生长性状的变化规律。结果表明,油菜在野燕麦的竞争干扰下,植株高度、分枝数、角果数及千粒重均随其密度的增加而显著降低,而第一分枝高度则不断增加。野燕麦能显著降低油菜植株间的透光率,其对田间25 cm高处的透光率影响较大,对75 cm和50 cm高处的透光率影响相对较小。野燕麦密度为5株&#8226;m-2时油菜产量显著降低,当其密度达到160株&#8226;m-2以上时,可使油菜减产达90%以上。对数模型y = 15.436lnx + 8.475可以较好地拟合野燕麦与油菜产量损失间的关系（P<0.0001）。油菜田野燕麦人工防除的经济阈值为1.15株&#8226;m-2,使用精噁唑禾草灵化学防除的经济阈值为0.70株&#8226;m-2。     

窄行平作密植大豆田杂草的危害特点

化学除草是窄行平作密植大豆田唯一的杂草防除方式,草害水平和除草时期将直接影响化学除草的经济效益.研究不同杂草发生密度及与大豆共生时期对窄行平作密植栽培模式下大豆产量的影响,以明确窄行平作密植大豆田杂草化学防除的适宜时期和草害水平,提高化学除草的效益.利用对角线五点取样法,调查了窄行平作密植大豆田杂草的危害特点.结果表明:野燕麦发生密度(x)与大豆收益(y)之间的曲线关系为y=2267.2Ln(x)-4934.2,野燕麦的理论密度阈限为10.75株·m-2;苍耳发生密度为6株·m-2时,与大豆全生育期共生使大豆减产61.1%.     

甲黄隆对tralkoxydim在野燕麦中的拮抗作用

在室内试验中，增加甲黄隆喷雾能显著减少ｔｒａｌｋｏｘｙｄｉｍ防除野燕麦的活性。该现象在ｔｒａｌｋｏｘｙｄｉｍ低剂量（例如，１２５ｇａ．ｉ／ｈａ）和甲黄隆高剂量（８或１２ｇａ．ｉ／ｈａ）使用时非常明显。甲黄隆能单独显著地使野燕麦生长发育减少。而绿磺隆在剂量达到３３ｇａ．ｉ．／ｈａ仍不能减小野燕麦生长，只能引致ｔｒａｌｋｏｘｙｄｉｍ的活性轻微的下降。在混合使用时，施药后６ｈ时甲黄隆能使施在叶片上的＾１     

甲黄隆对tralkoxydim在野燕麦中的拮抗作用

在室内试验中，增加甲黄隆喷雾能显著减少ｔｒａｌｋｏｘｙｄｉｍ防除野燕麦的活性。该现象在 ｔｒａｌｋｏｘｙｄｉｍ低剂量（例如，１２５ｇａ．ｉ／ｈａ）和甲黄隆高剂量（８或 １２ ｇａ．ｉ／ｈａ）使用时非常明显。甲黄隆能单独显著地使野燕麦生长发育减少。而绿磺隆在剂量达到 ３３ｇａ．ｉ．／ｈａ仍不能减小野燕麦生长，只能引致 ｔｒａｌｋｏｘｙｄｉｍ的活性轻微的下降。在混合使用时，施药后６ｈ时甲黄隆能使施在叶片上的１４Ｃ－ｔｒａｌｘｏｘｙｄｉｍ的吸收减小，但是在后来的取样时间里不影响１４Ｃ－ｔｒａｌｋｏｘｙｄｉｍ的吸收和移动。在体外分析中，分析剂中的甲黄隆１０μＭ 和１００μＭ对野燕麦辅酶羧酸酶（ＡＣＣａｓｅ）的活性无影响，也不干扰ｔｒａｌｋｏｘｙｄｉｍ对ＡＣＣａｓｃ的抑制作用。另外，用甲黄隆４，８和１２ｇ／ｈａ处理野燕麦植株，喷药后２４－９６ｈ收获时，并没有降低可提取的 ＡＣＣａｓｅ的活性水平。甲黄隆对生长发育的暂时性抑制为绝大部分ｔｒａｌｋｏｘｙｄｉｍ代谢为无活性物质提供了充足的持续时间，因此减少了ｔｒａｌｋｏｘｙｄｉｍ所引致的损害。     

Factors in the Reduction in Grain Number in Winter Wheat by Early-Sowing in Yamaguchi

Abstract

Grain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike.     

Allelopathy in Agroecosystems in Spain

Summary

This paper reviews the effects of allelopathic interactions in agroecosystems in Spain on plant physiological activity and their ecological advantages. The phenological stage of growth of donor plants and the effective allelochemicals in the soil solution while studying the role of phenolic compounds were highlighting. Finally possible future prospects and conclusions regarding weed control by allelochemi-cals under integrated crop management strategies are discussed.     

2009年中国稻米市场分析及2010年展望

以翔实的资料对2009年中国稻米生产、消费、进出口、供求平衡、库存、价格走势、购销政策和国际稻米供求等情况进行了全面地分析,对影响2010年稻米市场价格走势的各种因素进行了深入研究,并在此基础上对2010年我国稻米市场价格走势进行了预测,结论是我国稻米价格仍呈上行趋势。     

Advances in Variable Rate Technology Application in Potato in The Netherlands

Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed.     

我国高粱育种研究进展

对我国高粱育种的主要途径和研究方向进行了概述,针对目前高粱产量徘徊现象,提出了高粱超高产育种设想,并对其技术路线进行了探讨。     

Diurnal changes in net photosynthetic rate in potato in two environments

Summary Diurnal changes in net photosynthetic rate were measured in a furrow-irrigated potato crop and in a riverbed crop where the water table was always maintained at 20–28 cm from the soil surface. In the irrigated crop, the photosynthetic rate during mid-afternoon was about half the peak rate observed at noon. This reduction was accompanied by a near tripling of stomatal resistance, a 45% reduction in transpiration, and a 5-fold increase in the difference between leaf and air temperatures. No such changes were observed in the riverbed crop where the photosynthetic rate remained nearly constant at about 0.9 mg m⁻² s⁻¹ between 9 a.m. and 4 p.m. Tuber yield in the riverbed crop was about 30% higher than in the irrigated crop.     

我国干热区甘蔗抗旱植蔗主要问题研讨

我国干热蔗区是我国甘蔗糖业的重要生产基地,蔗区光热资源丰富,唯降水分布不均成为植蔗生产的主要限制因子;根据蔗区植蔗特点和甘蔗需水规律,苗期抗旱是干热蔗区抗旱植蔗的关键,保证较多的总苗数和足够的生长量是苗期抗旱植蔗需解决的关键技术难题,制定相应的苗期抗旱植蔗栽培技术措施是解决该难题的重要保障;该观点为我国干热蔗区植蔗生产、甘蔗引育种提供理论和技术支持。     

棉花体细胞无性系变异的研究进展

体细胞无性系变异是一种重要的细胞工程育种技术,其应用于棉花育种的前提是建立高效的组织培养诱导再生植株体系.本文简要综述了棉花离体诱导植株再生研究的现状,重点讨论了棉花体细胞无性系变异的表现、利用方法及机理,提出了当前研究存在的问题并对今后的研究进行了展望.