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971.
Exploring and utilizing resistant germplasm resources plays a pivotal role in breeding for disease resistance, while screening resistant germplasm is important for selecting and breeding varieties resistant to disease. In the present study, we used PCR to detect the ratoon stunting disease (RSD) bacterium Leifsonia xyli subsp. xyli (Lxx) in 137 sugarcane core germplasms from the National Nursery of Sugarcane Germplasm Resources (NNSGR, Kaiyuan, China) in 2009, 2010 and 2011. A total of 21 germplasms that tested negative for Lxx in 2009 and 2010 were selected for further Lxx detection after being subjected to artificial inoculation in 2011 and 2012. The 21 core germplasms that were negative for Lxx after natural infection and artificial inoculation can provide elite resistance source materials and reference frames for the effective breeding of RSD-resistant sugarcane varieties. Under natural conditions, 116 (84.67%) and 21 (15.33%) out of 137 germplasms were positive and negative for Lxx, respectively, as determined by PCR detection, which suggests that a relatively high ratio of sugarcane core germplasms was sensitive to RSD, while few were resistant to RSD. The sequencing and analysis of 30 randomly selected PCR products showed that all 30 sequences were identical or highly homologous to the corresponding Lxx genome region published in GenBank (99.54–100% similarity). Lxx can be detected effectively and precisely by PCR. We therefore recommend PCR as a rapid, low cost and simple procedure to score sugarcane core germplasms for RSD resistance.  相似文献   
972.
介绍了冷凉地区繁育的百合种球的采收和冷处理技术,包括采收时间和标准、挖球、冷库消毒及摆放等.  相似文献   
973.
为探明Mn2+在植物抗冷性中的作用,试验以黄瓜幼苗为试材,研究不同Mn2+浓度对黄瓜抗冷性的影响。结果表明,提高Mn2+浓度可显著增强黄瓜幼苗抗冷性,以Mn2+标准浓度的10倍处理效果最显著。  相似文献   
974.
本研究利用鲜血琼脂和营养琼脂培养基,从自然发病的鸭体内成功分离出链球菌19株,革兰氏染色镜检可见革兰氏阳性球菌呈长链状排列,生化试验和动物接种试验结果表明,所分离的细菌对鸭有致病性。药敏试验结果表明,分离的菌株耐药性均很强,除7株对丁胺卡那中度敏感外,其余菌株对丁胺卡那、头孢曲松钠、氧氟沙星等14种药物低度敏感或不敏感。说明鸭链球菌耐药性在不断增强,给鸭链球菌病的防治带来了一定的困难。  相似文献   
975.
在不同低温处理下,分别对引进的3个品系欧洲报春叶片和花进行相对电导率及游离脯氨酸含量测定,分析其抗寒性的差异,结果表明:3个品系的欧洲报春花叶片伤害度、半致死温度和游离脯氨酸含量变化较为相符,其叶片和花的耐寒性强弱为:丹若娃的叶片>里拉的叶片>妃纯的叶片;妃纯的花>丹若娃的花>里拉的花,与其在露地栽培中观察到的结果相符。  相似文献   
976.
从探险家发现南极鱼到科学家在南极鱼体内找到抗冷冻蛋白,联想到如何挖掘骆驼所具有的抗逆性。围绕骆驼特有的耐热、耐渴、耐寒、耐饿、耐粗饲料等生物学特性,对驼产业的开发与利用提出了新的思路。  相似文献   
977.
23个欧美杨无性系苗期叶锈病抗性测定   总被引:2,自引:0,他引:2  
以引进23个欧美杨无性系为研究对象,通过对苗木叶锈病感病指数的调查,借助SPSS统计软件对调查数据进行统计分析,结果表明:对叶锈病的抗性表现超过对照品种I108的有19个,其中02-36-1、02-36-4、N177、N197和N195这5个无性系对叶锈病完全免疫;无性系02-34-334对叶锈病表现为高度抗病;02-01-119、324、03-04-111、03-04-97和02-34-278表现为抗病;03-04-141、03-04-170、02-34-347和03-05-184表现为感病;02-01-219、03-04-167、03-04-288和02-34-228表现为高感;对叶锈病的抗性表现不及对照品种I108的有3个,即03-05-206、03-04-171和03-05-156,均表现为高感。  相似文献   
978.
设计了一种多功能电话电路,能够防止他人非法串线盗打和窃听电话,通过单片机控制自动存储并显示电话号码和所打电话的时刻及用时,且可通过打印机接口打印以上信息。  相似文献   
979.
When testing the response of species of the genusNicotiana to 14 isolates of potato viruses A (PVA), X (PVX) and Y (PVY) and tobacco mosaic virus (TMV), sections and section parts of the genus could be divided into five groups according to the overall reaction of their species. Species from arid regions of australia and belonging to the sectionSuaveolentes (subgenusPetunioides) were most sensitive and least resistant, whereas the sectionsPaniculatae (subgenusRustica),Tomentosae (Tabacum) andNoctiflorae (Petunioides) appeared least sensitive and most resistant. Sixty-one percent of the accessions of the latter sections proved resistant to at least two of the viruses. The most resistant species have their main geographical distribution in the central Andes (southern Peru, Bolivia and north-western Argentina), where the viruses may have originated. One other resistant species wasN. africana (Suaveolentes) indigenous to south-western Africa. The most sensitive American sections, viz.Genuinae (Tabacum) andTrigonophyllae, Alatae, Acuminatae andBigelovianae (Petunioides), were generally more sensitive than species of theSuaveolentes section from outside the arid regions of Australia. The remaining part of the genus, viz. the American sectionsThyrsiflorae andRusticae (Rustica) andUndulatae, Repandea andNudicaules (Petunioides) was intermediate between the latter group ofSuaveolentes species and the resistant group of sections with regard to sensitivity and resistance, but had a high rate of tolerance to PVA, PVX and PVY and of hypersensitivity-associated resistance to TMV. The results indicate that the viral respons in the genusNicotiana is mainly determined geographically and to a lesser extent taxonomically.Samenvatting Na inoculatie van een grote collectieNicotiana-soorten met 14 isolaten van de aardappelvirussen A (PVA), X (PVX) en Y (PVY) en tabaksmozaïekvirus (TMV), konden de secties of sectiedelen van het genus op basis van de gemiddelde reactie van hun soorten in vijf groepen worden verdeeld. Soorten uit Australische woestijngebieden en taxonomisch behorend tot de sectieSuaveolentes (subgenusPetunioides) bleken het meest gevoelig en het minst resistent, terwijl de sectiesPaniculatae (subgenusRustica),Tomentosae (Tabacum) enNoctiflorae (Petunioides) het minst gevoelig en het meest resistent waren. Van de collectienummers van de laatstgenoemde secties bleek 61% resistentie tegen minstens twee van de virussen te bezitten. De meest resistente soorten hebben hun verspreidingsgebied vooral in het centrale deel van het Andesgebergte (het zuidelijk deel van Peru, Bolivia en noord-westelijk Argentinië). Mogelijk is dit het ontstaansgebied van deze virussen. De einge andere resistente soort wasN. africana (Suaveolentes) uit zuid-westelijk Afrika. De meest gevoelige Amerikaanse secties, te wetenGenuinae (Tabacum) enTrigonophyllae, Alatae, Acuminatae enBigelovianae (Petunioides), waren gemiddeld gevoeliger danSuaveolentes-soorten die niet uit de Australische woestijnen afkomstig zijn. Het resterende deel van het genus, bestaande uit de Amerikaanse sectiesThyrsiflorae enRusticae (Rustica) enUndulatae, Repandae enNudicaules (Petunioides), stond met betrekking tot gevoeligheid en resistentie tussen laatstgenoemd deel van de sectieSuaveolentes en de groep resistente secties in, maar vertoonde in hoge mate tolerantie voor PVA, PVX en PVY en met overgevoeligheid samengaande resistentie voor TMV. Uit de resultaten blijkt dat de reacties van het genusNicotiana op virussen vooral geografisch bepaald zijn en in mindere mate taxonomisch.  相似文献   
980.
The morphological basis of resistance to the whiteflyBemisia tabaci Genn. (Aleyrodidae: Hemiptera) was studied. The plant characters examined were leaf area, thickness of leaf lamina, hair density, hair length, angle of insertion of leaf hair, and density of gossypol glands. Hair density and leaf thickness were positively correlated with the population ofB. tabaci, and a positive correlation was obtained between the adult whitefly population and gossypol glands on stem internodes. Cotton genotype USA-22 (sparsely hairy) was found to be more tolerant toB. tabaci than was genotype USA-13 (velvety hairy). The use of thinner and glabrous leaved cotton varieties is suggested to minimize the whitefly menace in cotton.  相似文献   
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