共查询到19条相似文献，搜索用时 234 毫秒
1.
北方春玉米产区因玉米螟危害,一般年份减产10%。据内蒙古自治区通辽植保站多年测定:田间玉米螟危害株率30%时,产量损失率为8%~10%;危害株率50%时,损失率为10%~15%。据统计,仅吉林省每年因玉米螟危害损失玉米产量5亿kg以上,因此了解玉米螟发展态势及防治措施非常必要。 相似文献
2.
大豆食心虫预报防治指标的确定 总被引：1，自引：0，他引：1
大豆收获前,选当地主栽品种,虫食率在60～80％的大豆地15～20块。每块地用大五点取样法,每个点取10株,共50株,自然干燥后,逐荚脱粒。混合均匀,随机取样,重复4次。每次取完整粒和虫食粒各1000粒,称百粒重。 1.大豆食心虫率与产量损失的关系 用完整粒百粒重减去虫食粒百粒重的差值是绝对产量损失,再除以完整粒百粒重所得是绝对重量减少百分率,然后乘以虫食率即为产量损失率。例如,嫩丰10号大豆田间虫食率6％,完整粒百粒重 相似文献
3.
<正> 近几年来,随着农业种植业结构的调整及抗虫棉种植面积的连年扩大,主要害虫棉铃虫已经降为次要害虫,而以往的次要害虫棉盲蝽为害却逐年加重。据笔者今年调查,平均百株虫量达20～30头,最高达65头,棉花平均百株受害率57%,叶片平均受害率82%,蕾铃脱落中有50%～60%是由棉盲蝽为害造成的。棉盲蝽常造成叶片破 相似文献
4.
5.
湖南省棉铃虫对棉花的为害和防治指标研究 总被引：3，自引：0，他引：3
用自然感虫与人工控制虫量的方法,研究棉铃虫三代和四代的虫口密度与棉花产量之间的关系.结果表明,棉花对于三代棉铃虫为害的补偿能力比四代的强.根据田间小区试验结果得出百株虫量与产量损失的关系为,Y三代＝1.0+1.379lnx±2.4;Y四代＝-7.910+3.855lnx±1.92,按照防治的直接收益与直接成本,确定了本省的不同产量水平下棉铃虫的经济阈值,即三代为百株幼虫6～10条,或百株累计卵量36～60粒;四代为百株幼虫17～20条,或百株累计卵量60～96粒. 相似文献
6.
甘蓝型三系杂交油菜秋播制种母本打薹及适宜施肥技术研究 总被引：1，自引：1，他引：0
油菜打薹杆株需要有较强的长势,才能使其再生分枝和花蕾角果较多。研究表明:在密度为3万株/公顷的情况下,以施纯氮207kg/公顷的处理,冬前绿叶数达13.7—14.5片,最大叶长达37—40cm;成熟期小分枝数在100个以上,单株有效角1286.4个;产量达到1046kg—1326kg/公顷,与施纯氮276kg的产量差异不显著;杂种不育株率为13％左右,比施氮量为276kg/公顷的不育株率低4.6％—5.0％。 相似文献
7.
亚洲玉米螟发生动态及释放松毛虫赤眼蜂防治效果 总被引：2，自引：1，他引：1
于2007年6月和9月对秦皇岛亚洲玉米螟在春玉米田间落卵量和亚洲玉米螟为害春玉米的严重程度及7月29日分别在春玉米地和夏玉米地释放松毛虫赤眼蜂防治第二代亚洲玉米螟效果进行了调查与研究,结果表明,亚洲玉米螟在该地区全年共发生两代,产卵高峰期分别发生在6月中旬和8月上旬,高峰期卵粒数分别达到了800粒和748粒;田间花叶率、百株蛀茎孔数、蛀茎株率和百株蛀穗孔数、蛀穗株率分别达到了78%、340个、96%和102个、74%;松毛虫赤眼蜂在春玉米地和夏玉米地卵块寄生率分别达到了80.00%和81.44%,在夏玉米地,放蜂区和对照区相比,蛀茎虫孔减退率为53.05%,蛀穗虫孔减退率为69.63%。通过本文分析得出亚洲玉米螟在秦皇岛地区发生及危害严重,释放松毛虫赤眼蜂防治效果较好。 相似文献
8.
9.
该试验设计49 500～79 500株/hm~25个密度梯度对玉米品种顺单7号母本产量性状、产量构成因素及制种产量进行研究。结果表明:1)随着种植密度的增加,产量性状中的空杆率不断增加,以最高密度79 500株/hm~2时的空杆率最高,为5.9%。双穗率逐渐下降,当密度高于72 000株/hm~2时,双穗率为0;2)产量与产量构成因素中的有效穗数呈正相关,与穗行数、行粒数、百粒重呈负相关,有效穗数的增产效应有效弥补了穗行数、行粒数、百粒重的减产效应;3)产量与密度之间存在一元二次函数关系,回归方程为:Y=-0.000 003 X2+0.413 793 X-10 344.489 6,顺单7号制种密度为68 966株/hm~2时,理论产量达到最大值3 924.2kg/hm~2。 相似文献
10.
苏棉15是江苏沿海地区农科所1985年配置的杂交组合(冀合328×泗棉2号)×徐州576,通过病圃筛选,南繁加代,多次连续单株选择于1991年得到株行1186。1999年4月通过江苏省农作物品种审定委员会审定。丰产性突出 1996~1997年参加江苏省中熟抗病棉区域试验,平均子棉产量3645kg/hm2,皮棉产量1469.4kg/hm2分别比对照泗棉3号增产12.40％和7.38％,差异均达极显著水平。1998年参加江苏省中熟抗病棉生产试验,平均子棉产量3553.95kg/hm2,皮棉产量1440.45kg/hm2,分别比对照泗棉3号增产9.82％和7.37％。纤维品质优良 经品质测试和大样试 相似文献
11.
12.
昆虫取食诱导棉花和玉米多酚氧化酶和过氧化物酶的活性研究 总被引：2，自引：0，他引：2
为了明确昆虫取食诱导植物间的通讯作用机制,研究了棉蚜取食和机械损伤诱导棉花及其邻近玉米,以及玉米螟取食和机械损伤诱导玉米及其邻近棉花的诱导防御机制。利用分光光度计法测定不同处理棉花和玉米的多酚氧化酶及过氧化物酶的活性。结果表明棉蚜取食和机械损伤诱导棉花多酚氧化酶和过氧化物酶的活性增加,棉蚜取食诱导棉花多酚氧化酶的活性是对照的1.61倍,机械损伤诱导棉花过氧化物酶的活性是对照的1.84倍,2种处理与对照相比差异均显著。玉米螟取食和机械损伤诱导玉米多酚氧化酶的活性增加但与对照比差异都不显著,而其相应过氧化物酶的活性显著高于对照,分别为对照的4.79和3.56倍。棉蚜取食和机械损伤诱导相应邻近健康玉米及玉米螟取食和机械损伤诱导其相应健康棉花的多酚氧化酶和过氧化物酶活性都没有增加。由此认为,多酚氧化酶和过氧化物酶在昆虫取食诱导的棉花和玉米通讯中的作用不明显。 相似文献
13.
G. Wang M. Gutierrez R. K. Asiimwe M. Zarnstorff 《Journal of Agronomy and Crop Science》2011,197(2):155-163
Cotton response to fruiting branch removal (FBR) is critical information in estimating plant recovery potential and making management decisions after hail storms or other physical damages. Fruiting branches were removed at first bloom (R8), 2.5‐cm boll (R12) and peak bloom (R16) growth stages. Five FBR treatments were conducted at each of the above three growth stages: 0 %, 25 %, 50 %, 75 % and 100 %. At harvest, five plants were randomly chosen from each plot and branches separated into three groups: vegetative, lower and upper fruiting branches. Lower fruiting branches were from the nodes where FBR treatments were conducted, whereas upper fruiting branches were the new branches developed after FBR. Seed cotton weight, open boll number and node number in each group were recorded. Fruiting branch removal increased boll number, boll size and boll/node on the upper fruiting branches, which compensated yield loss on lower fruiting branches. Generally, FBR at the first bloom reduced cotton yield more than it did at the 2.5‐cm boll and peak bloom growth stages when FBR percentage was lower than 75 %. The removal of all 16 fruiting branches at peak bloom reduced cotton yield by 16.8 %, indicating remarkable compensation ability by cotton plants in climates with a long growing season. 相似文献
14.
转Bt基因玉米对亚洲玉米螟的抗性评价 总被引：7，自引：0，他引：7
转Bt基因抗虫玉米为诺华公司含Bt11转化系的杂交种NX4777,能全株表达Cry1Ab杀虫蛋白,以其非转基因受体玉米品种NX4906为对照。在玉米生长至心叶中期(50~60cm高)、抽雄前期和抽丝散粉期分别进行人工接亚洲玉米螟[Ostrinia furnacalis (Guenée)]初孵幼虫40~60头。以食叶级别、存活幼虫数、蛀孔数、隧道长度和雌穗被害级别等,分别作为评价玉米心叶期和穗期的抗性标准。结果表明,Bt玉米食叶级别仅为1级,显著低于对照的7级。Bt玉米平均每株存活幼虫0.04~0.20头、蛀孔0.11~0.15个、隧道长度0.13~0.41cm,雌穗被害级别为0,植株折茎率为0,而对照玉米平均每株存活幼虫6.19~12.41头、蛀孔4.48~7.05个、隧道长度12.41~24.09cm,雌穗被害级别为5.9,植株折茎率高达73.6%~95.5%。室内生测结果亦表明,取食Bt玉米心叶、雄穗的初孵幼虫3d全部死亡,取食花丝7d死亡率达到99%,相比之下取食常规玉米的存活率在88.7%以上。表明表达Cry1Ab杀虫蛋白的Bt对亚洲玉米螟具有很高的抗虫性,能够保护玉米全生育期免受玉米螟的危害。 相似文献
15.
亚洲玉米螟优良球孢白僵菌菌株的筛选 总被引：4，自引：1，他引：3
本研究选择从亚洲玉米螟和桃蛀螟僵虫中分离纯化到的5个球孢白僵菌野生菌株,进行了毒力、菌株生长速率、产孢量和孢子萌发率的测定,筛选出了两株高毒力菌株B6和B17,在108孢子/mL浓度下对亚洲玉米螟的致死率分别为95.4％和90.8％,僵虫率分别为94.4％和87.8％,LT50分别为4.4d和4.7d;其LC50分别为1.3×106孢子/mL和2.8×106孢子/mL。而且这两株菌株显现出良好的生物学特性,具有较大生产潜力。 相似文献
16.
[Objective] Waterlogging adversely affects cotton growth and development, and continuous waterlogging may further result in considerable yield loss or crop failure. Enhancing the ability of cotton to adapt to waterlogging stress to preserve yield and quality is therefore critical. Ethylene is an important signal molecule, which plays a vital role in the process of plant stress resistance. However, the mechanism of ethylene in mitigating cotton waterlogging damage is still unclear. [Method] In this study, we setup an experiment with a cotton (Gossypium hirsutum L.) variety K638 in an electric rain shelter at the experimental station of the Shandong Cotton Research Center at Linqing, Shandong. We treated the cotton plants by waterlogging for 10 d during the flowering stage and used a non-waterlogged treatment as the control. During the waterlogging stress treatment, cotton plants were treated with an ethylene signal transduction inhibitor (1-MCP) or ethylene synthesis precursor (ACC) to detect the effects of ethylene content on cotton waterlogging injury and its physiological mechanism. [Result] The results revealed that a foliar spray of 1-MCP significantly inhibited ethylene synthesis in the stressed cotton plants, the content of ethylene and malondialdehyde (MDA) decreased by 5.3% and 39.2%, and the activities of alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC), and lactate dehydrogenase (LDH) decreased by 37.8%, 20.5%, and 8.2%, respectively. The photosynthetic rate, dry weight of the whole plant, and seed cotton yield increased by 13.5%, 3.3%, and 4.6%, respectively. The effect of ACC on the plants was the opposite because spraying ACC promoted ethylene accumulation in the waterlogged cotton. The ethylene and MDA content increased by 8.0% and 19.5%, respectively. The activities of ADH, PDC, and LDH increased by 17.5%, 11.2%, and 8.0%, respectively, while the photosynthetic rate, dry weight of the whole plant, and seed cotton yield decreased by 6.0%, 7.7%, and 8.0%, respectively. [Conclusion] In summary, reducing ethylene content in waterlogged cotton plants can significantly alleviate hypoxia damage caused by waterlogging stress and subsequently promote cotton growth and development by restoring physiological metabolism. 相似文献
17.
为了探究简化栽培措施对不同类型棉花品种产量和纤维品质性状的影响程度,以3种类型棉花品种为试验材料,在中等密度（5.2万株/hm2）条件下研究常规整枝和不整枝2种栽培方式对棉花产量及纤维品质性状的影响。结果表明整枝措施对不同类型棉花品种的铃重、籽指、衣分、纤维长度、马克隆值、整齐度指数、伸长率均没有显著影响,对纤维比强度影响显著(F=7.27);整枝和品种类型对棉花产量构成因素（铃重、籽指、衣分）和纤维品质性状均没有互作效应。在种植密度5.2万株/hm2时,整枝措施能提高棉花品种的纤维比强度,对棉花产量构成因素（铃重、籽指、衣分）无显著影响。 相似文献
18.
《European Journal of Agronomy》2011,34(4):285-292
Soil salinity is often heterogeneous, yet plant response to unequal salt distribution (USD) in the root zone is seldom studied in cotton (Gossypium hirsutum L.). Our objective was to evaluate the effects of USD on growth and yield, as well as its potential application for increasing cotton production. To achieve this objective, greenhouse and field experiments were conducted. In the first experiment, potted cotton plants were grown in a split-root system in the greenhouse. Each root half was irrigated with either the same or two concentrations of NaCl. Plant biomass, leaf chlorophyll (Chl), photosynthesis (Pn) and transpiration (Tr), Na+ and K+ accumulation, as well as biological and economic yields were determined. In the second experiment, plants were grown in furrow-beds in saline fields with those grown on flat beds as controls. Root-zone salinity, yield and yield components and earliness (the percentage of the first two harvests to total harvests) were monitored. When the entire root system was exposed to the same concentration of NaCl, shoot dry weight, leaf area, plant biomass, leaf Chl, Pn and Tr were markedly reduced relative to the NaCl-free control at 2 weeks after salinity stress (WAS). Significant reductions in biological (23.6–73.8%) and economic yields (38.1–79.7%) were noticed at harvest. However, when only half of the root system was exposed to low-salinity, the inhibition effect of salinity on growth and yield was significantly reduced. Plant biomass and seed cotton yield were increased by 13 and 23.9% with 50/150 mM/mM NaCl, 40 and 44.5% with 100/300 mM/mM NaCl, and 85.7 and 127.8% with 100/500 mM/mM NaCl relative to their respective equal salt distribution (ESD) controls (100/100, 200/200, and 300/300). Unequal salt distribution also decreased concentrations of Na+ and increased leaf K+ and Chl content, K+/Na+ ratio, Pn and Tr, compared with ESD. Furrow-bed seeding induced unequal distribution of salts in the surface soil during the field experiment. Under furrow planting, soil salinity was much higher, but soil osmotic potential was much lower on the ridged part than the furrows. Yield and earliness were increased 20.8 and 5.1% by furrow seeding relative to flat seeding. These enhancements were mainly attributed to unequal distribution of salts in the root zone. Thus, specific cultural practices that induce unequal salt distribution such as furrow-bed seeding can be used to improve cotton production in saline fields. 相似文献
19.
留叶枝去早果枝对抗虫棉生长发育及产量的影响 总被引：2，自引：1，他引：2
为探索留叶枝去早果枝对抗虫棉生长发育和产量的影响，于2004—2005年以两个不同熟性的抗虫棉品系K640和K9918为材料，在济南和临清进行了留叶枝去早果枝试验研究。结果表明，与正常整枝（去叶枝）相比，留叶枝去早果枝显著促进了两个品系的株高增长和叶面积扩展，叶面积系数提高了24%~94%。早熟品系K640在2004年和2005年分别比正常整枝增产7.4%和15.6%，而中早熟品系K9918的产量在2004年与正常整枝相当、2005年减产12.0%。留叶枝去早果枝显著减少了伏前桃比例，而相应提高了伏桃和秋桃的比例。留叶枝去早果枝对平均衣分影响不大，但显著影响铃数。分析认为，留叶枝去早果枝对棉花生长发育和产量的效应主要是通过提高叶源、降低库源比实现的，只有在叶源相对不足的情况下采取该措施才有增产作用。 相似文献