The Degradation of Starch in Apples Removed From the Tree at Different Stages of Development

The viruses cucumber mosaic (CMV), turnip mosaic (TuMV), broad bean wilt (BBWV), tomato aspermy (TAV) and tobravirus were isolated from field-grown spinach in Britain and identified by host range, electron microscopy and serology. CMV was most prevalent and widespread. Infected CMV-sensitive spinach cultivars usually showed diverse symptoms that were either associated with individual viruses or a mixture of TuMV and CMV. CMV-tolerant cultivars were symptomless when infected with CMV alone but produced diverse symptoms when infected with other viruses. In field experiments there was an association between trap catches of winged aphids and CMV incidence. Virus incidence was greatest in summer-sown crops, less in spring-sown and least in autumn-sown. Sap transmission tests showed CMV incidence to be similar in the CMV-tolerant and sensitive cultivars and that visual assessment underestimated virus incidence. A variant of a spinach CMV isolate overcome CMV tolerance with the production of severe symptoms and concomitant increase in virus content. CMV and BBWV reduced growth in a sensitive and BBWV in a tolerant cultivar.     

冬瓜人工接种5种病毒后的症状观察

选择5种在葫芦科作物上常见的病毒病原：小西葫芦黄花叶病毒（Zucchini yellow mosaic virus,ZYMV ）、西瓜花叶病毒（Watermelon mosaic virus,WMV）、黄瓜花叶病毒（Cucumber mosaic virus,CMV）、番木 瓜环斑病毒（Papaya ringspot virus,PRSV）、南瓜花叶病毒（Squash mosaic virus,SqMV）,人工接种子叶 期的冬瓜幼苗,观察分析5种病毒在冬瓜上的症状差异。结果表明：这5种病毒均可侵染冬瓜,且不同病毒在冬瓜 上的发病时间、发病率及症状存在明显差异：显症最早的是SqMV,最迟的是WMV;发病率普遍较低,都在30 %以下 ,ZYMV的发病率仅为4 %。     

新疆哈密瓜病毒的DAS-ELISA检测和分子鉴定

为了明确当前新疆哈密瓜病毒病的主要毒原种类及其遗传分化,为哈密瓜病毒病害的防治提供科学依据,对吐鲁番、鄯善、昌吉等哈密瓜主产区的病毒病调查、采样,采用双抗体夹心酶联免疫吸附法（DAS–ELISA）和RT-PCR技术对侵染哈密瓜的7种主要病毒及瓜类重要检疫性病毒--黄瓜绿斑驳花叶病毒（Cucumber green mottle mosaic virus,CGMMV）进行检测和分子鉴定。结果表明：在所检测的121个样品中,黄瓜花叶病毒（Cucumber mosaic virus,CMV）的检出率最高,为70.2%;西瓜花叶病毒（Watermelon mosaic virus,WMV）和小西葫芦黄花叶病毒（Zucchini yellow mosaic virus,ZYMV）次之,分别为62.0%和37.2%,甜瓜坏死斑点病毒（Melon necrotic spot virus,MNSV）的检出率仅为2.5%,CGMMV、南瓜花叶病毒（Squash mosaic virus,SqMV）、番木瓜环斑病毒（Papaya ring spot virus W,PRSV-W）和烟草坏死病毒（Tobacco necrosis virus,TNV）未检测到。CMV、WMV、ZYMV在田间分布广泛,2种及3种病毒的复合侵染发生普遍（60.19%）。对各病毒分离物进行CP基因扩增、序列测定和系统发育分析,确定了CMV新疆哈密瓜分离物归属于CMV亚组ⅠB。ZYMV、WMV和MNSV与已报道的病毒株系CP基因核苷酸序列具有较高的同源性,但存在一定的变异,ZYMV和WMV具有明显的地域分化现象。     

侵染节瓜的3种病毒多重PCR检测体系的建立

 根据侵染节瓜3种病毒——小西葫芦黄花叶病毒（ZYMV）、番木瓜环斑病毒（PRSV）和黄瓜花叶病毒（CMV）的外壳蛋白基因保守区序列设计特异引物,在建立各种病毒单项PCR技术的基础上,通过优化多重PCR反应条件,初步建立了能同步、快速、灵敏地检测这3种病毒的多重PCR检测体系,为节瓜病毒病原的检测提供了理论与技术支持。     

Three new vectors of papaya viruses

Seven aphids were tested for their ability to transmit 3 viruses of papaya. Mild mosaic virus (MMV) was transmitted by Aphis craccivora, A. gossypii and Myzus persicae. Distortion ringspot virus (DRV) was transmitted by A. nerii, Lipaphis pseudobrassicae and M. persicae. Ringspot virus (RSV) was transmitted only by M. persicae. Specificity of transmission by the aphid vectors of MMV and DRV was demonstrated. A. craccivora, A. nerii and L. pseudobrassicae are reported as new vectors of these viruses.     

PaLCuCNV和TYLCCNV复合侵染引起更严重的番茄黄化曲叶病

 从四川攀枝花市田间采集36份表现严重矮化、黄化和曲叶症状的番茄病株样本,利用双生病毒简并引物PA/PB从所有样本中均扩增得到约500 bp的片段,经全序列测定及分析,检测出中国番木瓜曲叶病毒（Papaya leaf curl China virus,PaLCuCNV）和中国番茄黄化曲叶病毒（Tomato yellow leaf curl China virus,TYLCCNV）,这两种双生病毒的复合侵染率达97.2%。系统进化分析表明,这两种双生病毒分别与已报道的PaLCuCNV河南番茄分离物（PaLCuCNV-[HeNZMI]）及TYLCCNV云南元谋烟草分离物（TYLCCNV-[Y295]）的核苷酸序列相似性最高,分别为99.1%和97.9%。检测发现,所有分离物均伴随有卫星DNA β分子,全序列测定表明所得9个DNA β分子均为TYLCCNV的卫星TYLCCNB,且与其四川番茄分离物（TYLCCNB-[SC65]）的核苷酸序列相似性最高,为87.7% ~ 94.5%。本文首次报道PaLCuCNV与TYLCCNV/TYLCCNB病害复合体复合侵染番茄引起更严重的番茄黄化曲叶病。     

早熟番茄新品种津粉207的选育

津粉207是利用自交系09-163为母本、10-202为父本杂交育成的番茄杂交一代品种。无限生长类型,耐低温,早熟、果实粉红、果形美观,单果质量在220 g以上,产量高,抗番茄黄化曲叶病毒病、烟草花叶病毒病和番茄灰叶斑病等,适宜华北地区早春保护地栽培。     

北京地区南瓜病毒病病原种类鉴定

为明确北京地区南瓜病毒病种类及其主要侵染病原,2016~2017年在北京周边采集疑似感染病毒的南瓜病样84份,并根据南瓜上的6种病毒特异性引物对其进行反转录PCR(RT-PCR)检测。结果表明:共有79份南瓜病样检测显示阳性,其中黄瓜花叶病毒(Cucumber mosaic virus,CMV)的检出率最高,为52.38%;其次是小西葫芦黄花叶病毒(Zucchini yellow mosaic virus,ZYMV)和西瓜花叶病毒(Watermelon mosaic virus,WMV),检出率分别为44.01%、14.29%,其他病毒暂未检出。此外,16.67%的样品受2种病毒复合侵染,CMV和ZYMV复合侵染占7.14%,ZYMV和WMV复合侵染占9.52%。北京地区南瓜上优势病毒种类为CMV,且存在病毒复合侵染现象。     

西瓜PRSV-W和ZYMV-CH抗性的遗传与连锁分析

番木瓜环斑病毒西瓜株系（PRSV—W）和小西葫芦黄化花叶病毒中国株系（ZYMV—CH）是危害我国西瓜的主要病害。以抗病毒病西瓜野生种质P．I．595203与感病普通西瓜自交系98R为亲本，采用单粒遗传方式得到109个F3代株系。分别对亲本、F1及F3代109个株系群体进行了苗期抗PRSV—W和ZYMV—CH接种鉴定，通过F3代群体的抗感分离情况来推测F2代单株的基因型，并分别对PRSV—W与ZYMV—CH抗性遗传及其这2个抗性基因的连锁关系进行分析。研究结果发现P．I．595203对PRSV—W的抗性是由单隐性基因控制，同时可能存在微效修饰基因，将此基因暂定名为prs—W；同时进一步证实了西瓜对ZYMV—CH的抗性由单隐性基因zym-CH控制，zym-CH和prs-W2个抗性基因在遗传上存在一定连锁关系，其遗传距离是27cM。     

番茄分子抗病育种研究进展

番茄生产中发生的严重病害多达40种,现从青枯病、烟草花叶病毒病、叶霉病、枯萎病、黄化曲叶病、番茄根结线虫病等主要病害上综述了番茄抗病分子育种的研究进展,并探讨了今后番茄分子抗病育种需要解决的问题和发展方向。     

江苏省番茄黄化曲叶病毒和褪绿病毒复合侵染的分子检测

2014年对江苏地区的番茄黄化曲叶病进行调查时发现,采自南京温室大棚的17份表现矮化,上部叶片上卷、变小、叶缘黄化,下部叶片脉间褪绿、上卷、变厚症状的番茄病株样本中除了感染烟粉虱传双生病毒外,还有一种长线形病毒,序列分析结果显示烟粉虱传双生病毒为番茄黄化曲叶病毒(Tomato yellow leaf curl virus,TYLCV),长线形病毒为番茄褪绿病毒(Tomato chlorosis virus,ToCV)。同时还对发病棚室中采集的烟粉虱进行了两种病毒的检测,结果两种病毒在烟粉虱体内都有检测到。     

Nucleotide sequencing and an improved diagnostic for screening okra (Abelmoschus esculentus L.) genotypes for resistance to a newly described begomovirus in India

Ten okra (Abelmoschus esculentus L.) plants showing distinct yellow vein mosaic disease (YVMD) symptoms were collected from different fields in Karnataka State, India. The genomic DNA of the isolated viruses was amplified, cloned, and sequenced. Sequence analysis revealed that the DNA-A-like sequences of all ten isolates were identical. Sequence analysis of a representative virus isolate (OYSK2) with other begomovirus sequences available in GenBank showed ≥90% sequence identity with Bhendi yellow vein Maharashtra virus (BYVMaV; EU482411) and ≤89% homology with full-length Bhendi yellow vein mosaic virus (BYVMV) infecting okra on the Indian subcontinent. These results suggested that a new strain of BYVMaV was present in all ten samples collected from the field. A source of resistance to BYVMaV and naturally present virus isolates causing YVMD was identified by screening okra genotypes under artificial and natural inoculation conditions, respectively. None of the genotypes tested showed complete immunity to BYVMaV. However, the okra genotypes ‘Tulasi’ and ‘Trisha’ were only moderately susceptible under glasshouse and field conditions. The new begomovirus strain could be detected by dot-blot hybridisation using a non-radioactive DNA probe in the virus samples collected from both symptomless and symptomatic okra plants.     

石河子地区加工番茄坏死条斑病毒原的ELISA检测及品种抗病性鉴定

用番茄花叶病毒、蚕豆萎蔫病毒和黄瓜花叶病毒的单克隆抗体对田间表现坏死条斑症状的315个加工番茄自然病株进行了ELISA检测。结果表明,这3种病毒的检测侵染率很高,分别为69.3 %、66.7 %和75.1 %,但其单一病毒的侵染率却很低,仅分别为1.5 %、2.4 %和8.5 %。表明这3种病毒是石河子地区加工番茄上的主要病毒种类,其复合侵染极可能是造成田间大量病株呈现严重坏死条斑症状的主要因素。并且对田间自然发病的21个加工番茄品种的上述3种病毒带毒情况进行了ELISA检测,虽然供试品种体内带毒量都较高,但品种之间却表现出一定的抗病性差异。     

北京、山东和广东黄瓜病毒检测

采集北京顺义和昌平、山东寿光及广东深圳等地田间感染病毒病的黄瓜材料284份,利用黄瓜花叶病毒(CMV)、西瓜花叶病毒(WMV)、小西葫芦黄花叶病毒(ZYMV)、黄瓜绿斑驳花叶病毒(CGMMV)及番木瓜环斑病毒(PRSV)5种黄瓜病毒抗体采用酶联免疫吸附(ELISA)法对其进行病毒病种类鉴定。结果表明,顺义和昌平采集到的126份和124份病毒样品,均在其叶片上检测到CMV、WMV、ZYMV 3种病毒,其中CMV检出率最高,均为100.00%;其次是ZYMV,检出率分别为80.95%和66.94%;WMV检出率最低,分别为51.59%和53.23%;在感病果实上只检测到CMV。在寿光采集的28份发病叶片中,检测到CMV、WMV、ZYMV、PRSV 4种病毒,其检出率分别为100.00%、35.71%、35.71%、17.86%。在深圳采集的6份黄瓜感病材料中,检测到CMV、WMV、PRSV 3种病毒,其检出率分别为100.00%、50.00%、50.00%。调查结果还发现,在北京顺义和昌平、山东寿光及广东深圳均存在2种或2种以上病毒复合侵染的现象。     

番茄抗病育种研究概况及展望

综述了近年来番茄在抗病育种中取得的进展,分别对抗黄化曲叶病毒病、青枯病、枯萎病及烟草花叶病毒病番茄育种现状进行总结,提出以常规杂交育种为主,同时结合分子标记辅助选择等生物技术手段的可行性育种方法及策略,并对今后番茄抗病育种及番茄产业的发展方向进行讨论与展望。     

The Production of Virus-Free Rhubarb by Apical Tip-Culture

The apical tip-culture technique has been used to produce virus-free rhubarb from infected plants of the varieties Timperley Early, Victoria and Prince Albert. Growth on various nutrient media was compared. The survival rate of the tips was directly related to their size within the range 300–2,500 μ (diam.). After initial culture on filter paper in sterile tubes, the young plants were transferred to autoclaved sand watered with mineral nutrient on which they made better growth than on other media.

Turnip mosaic, cherry leaf-roll, strawberry latent ringspot and cucumber mosaic viruses, in various combinations, were eliminated by this method. Arabis mosaic was removed from most plants but a few retained this virus. This retention was not related to the size of the tip taken.     

化学农药与芽胞杆菌M3、S11菌株对西芹黄萎病的防治效果

利用化学药剂与生防菌结合,对由尖孢镰刀菌芹菜专化型引起的西芹黄萎病进行综合防治研究。结果表明：苗期使用50 %多菌灵可湿性粉剂（WP）、50 %福美双•多菌灵WP（活根菌灭）或40 %噁霉灵WP（噁霉敌）灌根均能显著消除育苗基质中的病原菌孢子,孢子下降率达99.00 %以上;大田继续使用上述3种化学药剂或改用生防菌芽孢杆菌S11和M3,都能够显著降低西芹黄萎病发病率,防治效果最高为85.98 %;其中持续单独使用50 %多菌灵WP或苗期使用50 %多菌灵WP、大田改用生防菌芽孢杆菌对西芹的生长没有不良影响。     

芹菜斑枯病研究概述

芹菜斑枯病又叫晚疫病,是威胁芹菜生产的一种重要病害,在世界范围内都有发生,造成的损失高达50 ％～90 ％。本文综述了国内外学者对该病害的病原菌特性、发病症状、发病规律、防治措施、抗病性鉴定、遗传规律和抗病育种等方面的研究进展。     

优质芹菜新品种‘申芹2号’

‘申芹2号’芹菜是从‘荷兰红芹’和‘黄心芹’杂交后代中经多代分离纯化,选育而成的优质新品种。植株直立,株高55 ~ 60 cm。外叶黄绿色,心叶嫩黄色,叶柄黄绿带红,叶柄长35.6 cm,叶柄宽0.85 cm,叶柄基部宽1.15 cm。质地脆嫩,味清香,富含铁元素和芹菜素,纤维素含量低。生长速度快,定植后50 d开始收获,单株质量266 g,平均产量43 t · hm^-2。耐热性好,适宜长江中下游地区保护地和露地栽培。