利用低温或高温防控仓储绿豆象可行

<正>湖北省农科院粮食作物研究所近期研究证实,利用低温或高温而不用农药防控仓储绿豆象是可行的。研究人员首先在-5和40℃下,分别对绿豆象卵、幼虫、蛹和成虫进行处理,确定最耐受低温或者高温的虫态。在此基础上,对低温(-5、-10、-20℃)以及高温(40、45、50℃)下最耐受虫态做进一步的生物测定,从而得到完全防控绿豆象的时间。结果表明,绿豆象幼虫和蛹耐寒能力较强,卵、幼虫、蛹和成虫在-5℃的LT50(50%致死温度)分别是12.57、24.93、30.54和15.76小时;绿豆象蛹耐热能力较强,卵、幼虫、蛹和     

利用浅圆仓安全储藏小麦过程中技术应用分析

分析了利用3个浅圆仓分别储存小麦33和37个月的技术使用及粮情变化情况。结果表明适时使用机械通风技术和磷化氢双回路环流熏蒸技术可实现小麦安全储藏。仓温和平均粮温的最高值同时出现,且仓温高于平均粮温8.9℃;1～5月,平均粮温低于20℃,呈逐渐升高趋势;10月以后,平均粮温呈逐渐下降趋势。在小麦储藏期间,仓内相对湿度保持在60%左右。试验仓储藏期小麦品质符合宜存指标。     

温湿度对谷蠹（Rhyzopertha dominica）生长发育的影响

本试验通过全麦粉饲养,观察了谷蠹在不同温、湿度条件下的生物学习性和个体生态学特征,结果表明:1、谷蠹的发育温区为18-38℃,32-36℃为最适温度.2、不同温湿度条件下,谷蠹幼虫的龄数不完全一样,在适温范围内,低温低湿时其龄数较多,高温高湿龄数少,通常在3-8龄间变化,但以3或4龄居多.3、不同温湿度条件下,各虫态及幼虫各龄期和世代历期不一样,就虫态而言,以幼虫历期最长,蛹历期最短,就幼虫各龄而论,以1龄历期最长,低温低湿历期长,高温高湿历期短,世代历期在32.52～226.41天之间.4、该虫的发育起点温度和世代有效积温随相对湿度变化而不同,相对湿度为45%、55%、65%、75%、85%时,发育起点温度分别为:20.1、18.4、18、17.7、17.8℃,平均世代有效积温分别为:798.8,768.1,674.8,661.0,642.5日度.5、各虫态之间的转化率随温湿度变化也有差别,高温高湿,由卵向成虫的转化率较高(即死亡率低),低温低湿由卵向成虫的转化率低.在供试的温湿条件下,1龄幼虫的死亡率最高,蛹的死亡率极低.一旦化成蛹,几乎都能羽化为成虫.     

绿豆和小豆种子仓贮时绿豆象的防治

绿豆象又名豆牛、豆猴,是绿豆、小豆的主要仓库害虫.绿豆象成虫将卵散产于种子表面,孵化后幼虫蛀入粒中危害,10～17 d化蛹,蛹4～5 d羽化成虫.成虫寿命一般5～20 d,第2～4 d卵量最大.一年发生四五代,在24～30℃时繁殖最快,也在田间繁殖危害,10℃以下停止发育.一般被蛀的绿豆、小豆种子中空或种内成粉状,丧失发芽能力,严重时全部贮存种子被蛀空.为了保证绿豆、小豆种子的净度和发芽率,保证农业生产用种安全,可采取以下几种办法防治.     

地下仓小麦粮堆热湿传递试验研究

为了研究地下仓储粮期间小麦粮堆的温湿度变化,采用TOPRIE-TP700多路数据记录仪和TOPRIE-TP2305温湿度传感器对模型仓内小麦粮堆的温湿度进行了96 h实仓测试,并利用数值模拟软件COMSOL,通过简化内置质量守恒方程、能量守恒方程和动量守恒方程,对相同尺寸的地下仓进行了相同时长的数值模拟.通过模拟和实测数据进行对比得出:仓内空气域温度随外界环境温度变化而变化,波动幅度最大为1.2℃,且表现出滞后性,滞后时长达4h;随着纵向深度的增加,环境温度对小麦粮堆温度的影响越来越小,且浮升力的存在使得湿空气向空气域逸散,进而粮堆的相对湿度降低.     

聚苯乙烯（EPS）泡沫板粮面压盖隔热试验

应用聚苯乙烯（EPS）泡沫板对基建房式仓储存稻谷粮面进行压盖,经过21个月储存,两年的高温度夏试验表明,试验仓的粮温要比对照仓的粮温上升幅度低3℃～4℃,接近准低温储粮标准,粮温上升速度延缓2个月,储粮品质仍控制在“宜存”指标内,无黄粒米,虫口密度减少,未发生微虫物危害等.达到了隔热控温,延缓品质劣变,防虫抑霉的目的.     

高温处理对绿豆象不同虫态的致死效果

为明确绿豆象最耐受高温的虫态,获得该虫态完全防控温度和时间,为防治仓储绿豆象提供理论支撑。试验选择35℃、45℃、55℃3个温度对绿豆象的卵、幼虫、蛹、成虫分别处理30min、60min、90min、120min、150min、180min,测定不同温度条件不同处理时间后绿豆象各虫态的死亡率。结果显示：4种虫态中耐热性最强的虫态为绿豆象蛹期,绿豆象蛹期经55℃处理150min后,其死亡率达100%。因此,利用高温方法防治仓储绿豆象是可行的。     

浅圆仓大豆内环流均温试验研究

浅圆仓在冬季进行降温通风后,基础粮温较低(平均粮温5℃左右),入夏后"热皮冷心"现象比较明显,受外界高温影响,仓温、表层粮温升温明显,温度相对较高,仓温最高可达35℃以上,表层平均粮温在29℃左右,在此情况下,若储粮水分偏高,则上层粮面极易孳生虫霉,严重时可能引起表层储粮发热。因此,冬季对储粮仓房开展机械通风作业降低基础粮温进行蓄冷,夏季利用小功率风机将粮堆内部的冷空气通过地槽通风口抽出,通过仓壁回风管送到仓内空间,气流在粮堆内以下行的方式形成闭合回路,从而实现降低仓温、仓湿和表层粮温,达到控温储粮的目的。通过采用内环流均温通风的方式,利用粮堆内部冷源降低仓温及表层粮温,从而抑制表层大豆虫霉的孳生,延缓大豆品质劣变速度。试验期间,为确保对照仓储粮安全度夏,采取了夜间轴流风机排积热、单管处理异常粮情。同时期单吨费用对比,试验仓比对照仓节约0.1元/t左右。     

几种作物种子"双15"处理后低温贮藏生活力跟踪研究

利用IBPGR的"双15"(温度15℃、相对温度15%)干燥葙,将水稻、花生、小麦、兰豆、绿豆等种子进行"双15"干燥处理,分别在-1℃和-10℃两个低温干燥库贮藏149个月后检测,水稻含水量均比干燥前降低38.2%,发芽率保持在84%～96%,年降速率0.247%;未经"双15"处理进入同样低温干燥库贮藏的稻种最高年降速率3.05%;兰豆、小麦、绿豆种子在-1℃和-10℃两个低温干燥库贮藏含水量分别比干燥前降低44.67%、44.0%,发芽率为74%～93%,年降速率0.467%;花生种子在-1℃和-10℃两个低温干燥库贮藏含水量分别比干燥前降低41.5%、44.6%,发芽率为73%～92%,年降速率0.133%.作物种子含水量、发芽率的年降速率不同,豆类较大,水稻次之,花生较小,其下降值介于0.242%～0.54%和0.133%～0.467%之间.作物种子贮藏年限与发芽率呈极显著相关.表明作物种子资源用"双15"干燥处理后再低温贮藏可行.     

平房仓菱镁板隔热低温储粮应用试验

在平房仓仓顶铺设菱镁板,可有效控制仓温上升,使粮温保持相对较低状态;同时,对延长仓顶防水材料使用寿命、提高防水性能具有积极作用。4月至7月,铺设菱镁板的试验仓比对照仓的仓温和表层粮温低5℃左右,有效抑制了仓内害虫活动和繁殖,低温储粮效果得到增强。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...