18份广东香蕉种质对枯萎病的抗性评价

【背景】香蕉枯萎病是世界性的香蕉毁灭性病害,尚无有效药剂防控,筛选抗病品种是目前理想的防治方法。【方法】采用组培苗伤根接种法,研究了18份香蕉种质对香蕉枯萎病菌4号生理小种的抗性水平,并根据病情指数进行抗性分级。【结果】在供试的18份香蕉种质中,2份(东莞大蕉、抗枯5号)高抗,2份(碧盛、大丰)抗病,3份(抗枯1号、粉杂、农科1号)中抗,7份(粤优抗1号、广东-741、泰国B9、大蕉、台湾8号、海贡蕉、威廉斯8818)感病,4份(巴西、广东2号、广粉1号、粉蕉)高感。【结论与意义】不同香蕉种质对香蕉枯萎病菌4号生理小种的抗病性存在较大差异,本研究初步筛选出7份抗枯萎病的香蕉种质,为香蕉枯萎病抗病育种提供了依据,为病区种植香蕉品种提供了有效参考。     

不同品种花生的抗旱能力及其与内源ABA的关系

本文探讨10个花生（Arachis hypogaea L．）品种的抗旱能力与其内源ABA的关系。采用的花生品种有：‘粤油9’、‘粤油13’、‘粤油14’、‘粤油20’、‘粤油40’、‘粤油114’、‘湛油52’、‘秋45’、‘秋49’、‘秋86’,由广东省农业科学院作物研究所提供。     

烟草根黑腐病拮抗内生细菌的筛选及其抑菌作用

【目的】从烟草根、茎中分离获得对烟草根黑腐病菌(Thielaviopsis basicola)有较好控病作用的内生细菌。【方法】采用平板对峙培养,测定分离获得的306个内生细菌对烟草根黑腐病菌的抑制作用;通过菌株形态特征、生理生化特性及16S rDNA序列对菌株进行分类鉴定。【结果】筛选获得6个菌株对烟草根黑腐病菌有较强拮抗作用,室内测定其对病原菌的抑菌带宽达6.5 mm-11.0 mm,温室控病效果达11.9%-77.1%,其中来自茎部的内生细菌T295菌株对烟草根黑腐病的防效达77.1%;无菌滤液实验表明,拮抗内生细菌T295无菌滤液在实验浓度范围内对病菌菌丝生长、孢子萌发有较好地抑制作用。【结论】菌株T295对烟草根黑腐病具有较好的防治作用,经鉴定为枯草芽孢杆菌(Bacillussubtilis)。     

综合隶属函数法评价花生品种抗旱性与AhNCED1基因表达的关系

利用综合隶属函数法评价不同产地8个花生品种幼苗的抗旱能力, 同时分析各品种花生在模拟干旱处理2小时和12小时后叶片AhNCED1基因表达量的变化, 探讨花生品种抗旱性与叶片AhNCED1基因表达的关系, 建立花生(Arachis hypogaea)幼苗时期通过AhNCED1基因表达变化检测花生抗旱性等级的方法。结果显示, 干旱处理2小时, 各品种叶片AhNCED1基因表达量迅速增加, 与处理前相比差异极显著; 干旱处理12小时, 各品种花生叶片AhNCED1基因表达量均降低, 但仍均高于处理前水平。综合隶属函数值定量反映各品种抗旱性强弱顺序为: 花育24号>福花13号>粤油7号>中花15号>中花16号>航花2号>福花9号>北海1号。干旱处理2小时各品种花生叶片AhNCED1表达量变化大小依次为: 福花13号>花育24号>中花16号>中花15号>航花2号>粤油7号>北海1号>福花9号。其中, 抗旱性强的品种为花育24号和福花13号, 抗旱性弱的品种为福花9号和北海1号, 其余4个品种为中等抗旱。该抗旱性评价结果与这些品种在生产上的表现一致, 干旱胁迫2小时花生品种叶片AhNCED1基因的表达量变化与其抗旱性一致。因此, AhNCED1基因表达量可作为苗期花生品种抗旱性等级的量化指标之一。     

不同花生品种响应干旱胁迫后叶片内ABA与AhNCEDl的分布

以粤油7号和汕优523两个不同抗旱性品种为材料,研究响应干旱胁迫后叶片ABA（abscisicacid,脱落酸）和AhNCEDl（Arachishypogaeanine-cis-epoxycarotenoiddioxygenase）的分布以及含量变化。结果表明,两种花生品种响应干旱胁迫后叶片的维管组织中ABA分布增强且含量增加,AhNCEDl蛋白分布也增强;且在水分胁迫初期粤油7号花生AhNCEDl蛋白分布强于汕优523,其体内ABA分布水平也高于汕优523;经ABA生物合成抑制剂N印roxen处理后,两种花生叶片ABA分布减弱,但粤油7号叶片维管组织ABA分布水平仍高于汕优523。结果表明维管组织是干旱胁迫下花生叶片中ABA和AhNCEDl分布的主要区域,且粤油7号花生抗旱性强可能与其体内AhNCEDl和ABA的分布量较高有关。     

白色种皮花生皮色及农艺性状遗传的研究

为育成白色种皮的高产花生品种,了解白色种皮的遗传规律,用自育的白皮1号品种与在福建省生产上推广的红皮良种粤油116、汕油对和泉花10号进行杂交,杂种F1植株的种皮全为红色．F2红皮植株与白皮植株的分离比例符合15:1的分离规律,红皮F2代的F3代株系中,有4/15株系符合红：白为3:1的分离比例。由此推断白皮性状是两对隐性基因控制,白皮性状与产量性状没有连锁。主要农艺性状的遗传力顺序为：单株结果数＞单株饱果重和生物产量＞单株饱果数。经F3代、F4和F5代的株系鉴定,选出稳定、综合性状优良的重组类型;再经过产量鉴定和多点比较试验,选出了丰产性较好的二个品种参加福建省花生新品种区域试验．     

黄瓜资源对黄瓜绿斑驳病毒广东分离物的抗性水平鉴定

【背景】黄瓜绿斑驳花叶病毒(Cucumber green mottle mosaic virus,CGMMV)是严重威胁葫芦科作物生产的毁灭性病原之一,该病毒已入侵我国十多个省份,危害西瓜、黄瓜等作物并造成严重的经济损失。早在2009年广东即发现CGMMV为害西瓜和黄瓜,但黄瓜等葫芦科作物对其抗性情况尚不清楚。【方法】采用人工机械摩擦接种方法,测定了14份黄瓜种质资源对CGMMV广东分离物的抗性水平。【结果】从广东葫芦病样中分离获得CGMMV,该病毒分离物MP基因序列与国内报道的各分离物同源率均在99%以上;14份黄瓜种质资源对该病毒分离物均表现为感病。【结论与意义】广东主要黄瓜资源对CGMMV均表现为感病,这为我省防控该病毒病提供了科学依据,也为黄瓜抗病育种提供了指导。     

新疆油用型向日葵种质资源对2种新入侵病害的抗性鉴定与评价

【目的】向日葵白锈病、黑茎病是2种危害严重的新入侵病害,新疆地区新源县和特克斯县为这2种病害发生区。研究目前种植的油用型向日葵品种对向日葵白锈病和黑茎病的抗性差异,可为新疆伊犁地区向日葵品种选育及其病害综合防控提供理论依据。【方法】选择伊犁地区广泛种植的16种油用型向日葵种质资源为供试品种,试验地设在新源县和特克斯县田间,于2015年5—9月调查样地的病叶数,并计算病情指数,同时测定样地的平均产量,最后综合以上结果确定各品种的抗性水平。【结果】不同向日葵品种在同一供试条件下对白锈病和黑茎病存在明显的抗性差异,在新源县NX19012(西域朝阳)的病情指数分别为7.83和25.62,而品种KWS204的病情指数为21.04和39.50;部分品种在不同的供试地点表现出一致的抗性水平,品种新引S31感染白锈病后在新源县的病情指数为9.41,在特克斯县为9.38;另有部分品种在不同地点存在不同的抗性水平,如G101感染白锈病后在新源县和特克斯县的病情指数分别为9.16和11.78,而感染黑茎病后在新源县和特克斯县的病情指数分别为31.05和37.79。【结论】通过对白锈病和黑茎病病情指数、向日葵产量及当地气象数据的综合研究,发现NX19012(西域朝阳)最适宜在新疆伊犁地区种植,品种S606、TO12244、NX01025(西部骆驼)也可作为多样化种植的候选品种,而新葵杂系列品种中新葵杂5号可作为今后品种选育的试验材料。     

烟草抗黑胫病突变体的细胞筛选

经实验我们成功地建立了在细胞水平上筛选烟草抗黑胫病突变体的筛选体系。该体系的主要内容为:γ-射线500—2000拉德诱变高度感病品种的花药后用50—80％的黑胫病菌粗毒素为选择压力,筛选出抗毒素花粉植株,用离体叶片法测定选出抗病植株,再从后代鉴定中选出抗病性能够稳定遗传的突变系。γ-射线及高浓度毒素处理均能得到抗病植株。选自感病品种的花粉植株中约有9—50％是真正抗病的。这些抗病植株中有一部分的抗病性能够稳定遗传。用该法已从感病优质品种小黄金1025及乔庄黑苗中选出6个突变系。并自N.C.628(抗)×小黄金1025(感)及N.C.628(抗)×庆胜2号(感)的F_1花粉植株中选出4个抗病系。所有的抗病系经3—4代后均表现出稳定抗性。其中一个突变体(R400)的抗性似由不完全显性多基因控制。     

不同花生品种响应干旱胁迫后叶片内ABA与AhNCED1的分布

以粤油7号和汕优523两个不同抗旱性品种为材料,研究响应干旱胁迫后叶片ABA(abscisic acid,脱落酸)和AhNCED1(Arachis hypogaea nine-cis-epoxycarotenoid dioxygenase)的分布以及含量变化。结果表明,两种花生品种响应干旱胁迫后叶片的维管组织中ABA分布增强且含量增加,AhNCED1蛋白分布也增强;且在水分胁迫初期粤油7号花生AhNCED1蛋白分布强于汕优523,其体内ABA分布水平也高于汕优523;经ABA生物合成抑制剂Naproxen处理后,两种花生叶片ABA分布减弱,但粤油7号叶片维管组织中ABA分布水平仍高于汕优523。结果表明维管组织是干旱胁迫下花生叶片中ABA和AhNCED1分布的主要区域,且粤油7号花生抗旱性强可能与其体内AhNCED1和ABA的分布量较高有关。     

云南30个水稻品种对水稻白叶枯病的抗性评价

【目的】水稻白叶枯病是一种严重危害水稻的细菌性病害,培育抗性品种是治理该病害的重要途径。因此,明确云南水稻材料对检疫性病害水稻白叶枯病的抗性,可以为该病害的防治与监测、水稻栽培的合理布局和良好抗性资源的获取提供依据。【方法】采用剪叶接种法测定云南稻区30个品种对7个不同致病型白叶枯病菌的抗性。【结果】在供试的30个云南水稻品种中,2个品种(玉粳16和JS42糯稻)对7个不同致病型菌株均表现为抗性;15个品种对7个致病型菌株均表现感病;对HEN11、SCYC-6、YN7、YN11、FUJ、YN241和PX099等7个致病型菌株表现抗性的水稻品种分别占26.67%、16.67%、23.33%、13.33%、6.67%、10.00%和20.00%。此外,区试材料的抗性比例高于主栽品种,地方稻未发现抗性品种。【结论】现在生产上的大部分水稻品种对优势致病型病原菌入侵的抵抗能力降低甚至丧失。针对云南地区的优势致病小种FUJ筛选得到2个抗性品种:玉粳16和JS42糯稻。     

Susceptibility of eight potato cultivars to tuber infection by Phytophthora erythroseptica and Pythium ultimum and its relationship to mefenoxam-mediated control of pink rot and leak

In addition to cultural practices, the application of the fungicide mefenoxam is an important disease management tactic used to control both pink rot and leak on potato tubers grown in the USA. Mefenoxam resistance has been identified in many of the potato growing regions, and therefore resistance management strategies are very important for retaining this fungicide as a tool to manage these storage rot diseases. The relationship between mefenoxam efficacy and cultivar susceptibility to pink rot and leak was assessed in post‐harvest inoculation studies. Mefenoxam was applied to potato (Solanum tuberosum) cultivars known to express varying levels of susceptibility to pink rot and leak caused by Phytophthora erythroseptica and Pythium ultimum, respectfully. Tubers harvested from plants treated with in‐furrow and foliar applications of mefenoxam were inoculated with isolates sensitive to the fungicide. Incidence and severity of both diseases ranged widely among cultivars. Russet Norkotah was the most susceptible to infection by P. erythroseptica, while cvs Pike and Atlantic were the most resistant. Cultivars Dark Red Norland, Russet Norkotah, Goldrush and Russet Burbank were most susceptible to infection by P. ultimum whereas Snowden was most resistant. Control of pink rot differed significantly among cultivars following mefenoxam treatment, ranging from 28% (cv. Goldrush) to 67% (cv. Snowden) and generally provided the greatest level of disease control on susceptible and moderately susceptible cultivars such as Russet Norkotah and Snowden, respectively. In contrast, the impact of mefenoxam on leak development was minimal and disease control did not differ significantly among the cultivars. The fungicide failed to control leak in the susceptible cvs Atlantic and Pike and control ranged from 1.7% to 5.2% in cvs Goldrush, Russet Norkotah, Dark Red Norland, Russet Burbank and Kennebec. The greatest level of leak control was achieved with the moderately resistant cv., Snowden, at 12.7%. Cultivars most likely to benefit from mefenoxam treatments should be targeted as part of a pink rot management programme. Judicious use of the fungicide, when matched with the level of cultivar susceptibility, may prove to be an efficient and effective approach to reduce infection rates and possibly manage mefenoxam resistance thereby maintaining longevity of the compound.     

Changes in Peroxidase Activity during Potato Ring Rot Infection

The effects of the ring rot causal agent Clavibacter michiganensis subsp. sepedonicus (a virulent strain 5369) on the peroxidase activity of various tissues of potato plants grown under axenic conditions were studied. Root infection enhanced peroxidase activity in all plant tissues (roots, leaves, and stems). In the resistant cv. Lugovskoi, peroxidase activity was much higher than in the susceptible cv. Luk'yanovskii. Co-culturing of the suspension cells of these potato cultivars with the bacterial pathogen also activated peroxidase in the cells of the resistant cultivar; in the cells of the susceptible cultivar, peroxidase activation was less pronounced. Treating suspension cell with exopolysaccharides secreted by the pathogen enhanced the activity of extra- and intracellular peroxidases, and the degree of this enhancement differed in the two potato cultivars.     

Slow Rusting of Wheat to Puccinia recondita

Seven cultivars of winter wheat were studied in field trials to determine their level of slow rusting ability towards brown rust. Cv. Bouquet was the most resistant, with greatly reduced infection levels, areas under die disease progress curve and infection rate compared with those measured on the control cv. Armadda. Cultivars Atou and Maris Freeman also showed evidence of slow rusting, but the responses of cultivars Waggoner and Flinor were not consistent in successive trials. Cv. Flanders appeared to be almost as susceptible as cv. Armada. The use of the Gompertz transformation of desease progress data for the calculation of apparent infection rates allowed better comparison of rates between cultivars than when the logistic transformation was used.     

甘蔗鞭黑粉菌侵染甘蔗的早期可视化观察

[目的]甘蔗鞭黑粉菌(Sporisorium scitamineum)引起的甘蔗黑穗病是我国甘蔗生产重要的病害.示踪甘蔗鞭黑粉菌侵染甘蔗的过程将有助于揭示其致病性和甘蔗抗黑穗病机制,为抗病品种的选育以及黑穗病的防治奠定基础.[方法]利用农杆菌介导的遗传转化技术对甘蔗鞭黑粉菌进行黄色荧光标记,对转化子进行配合及致病力检测...     

Oviposition and larval survival of Dasineura tetensi on four blackcurrant Ribes cultivars

Monitoring of an unsprayed infested fieldsite using watertraps in S.E. Kent revealed four generations of Dasineura tetensi (Rubs) (Diptera: Cecidomyiidae) occurring between April and September 1996. Ribes nigrum L. cultivars 'Baldwin' (susceptible), 'Ben Alder' (susceptible) and 'Ben Connan' (resistant) were sampled for eggs in the field and assessed for midge damage throughout the season. Oviposition was indiscriminate, but plant damage varied significantly between cultivars. In laboratory choice experiments, mated female midges showed no preference between susceptible shoots of 'Ben Alder' and resistant shoots of 'Ben Connan' for oviposition. Olfactory responses of D. tetensi to leaf volatiles of 'Ben Alder' and 'Ben Connan' were also tested in a 4-way olfactometer. Mated females did not discriminate between volatiles of susceptible and resistant host plants. Larvae reared on cv. 'Ben Connan' shoots were significantly smaller than those reared on shoots of cv. 'Ben Alder'. Larval antibiosis and not female antixenosis appears to be the main mechanism for resistance to D. tetensi in 'Ben Connan'.     

Der mit der Versuchsdauer anwachsende Resistenzfaktor

Abstract

Pseudomonas spp. strains capable of inducing systemic resistance were applied to sugarcane by sett treatment followed by soil applications in the field. Later the fungal pathogen Colletotrichum falcatum causing red rot disease of sugarcane was inoculated in the treated canes and its colonization was assessed by ELISA at different nodal positions above the point of inoculation. Studies with three cvs showed a significant variation in pathogen colonization only in disease susceptible cv CoC 671 and not with cvs Co 8021 and BO 91, moderately susceptible and moderately resistant to the disease, respectively. In further studies when pathogen colonization was assessed on the entire stalks of cv CoC 671, the pathogen titre was significantly reduced from three nodes upwards in the treated canes. In the upper nodes no pathogen colonization was noticed in bacteria-treated canes, whereas in the control all the nodes recorded higher titre for pathogen infection. Incorporation of chitin in the talc formulation caused further reduction in fungal colonization in the stalks.