南瓜品种对自粉病的抗病性与叶绿素含量和气孔密度的相关性

不同南瓜品种对白粉病的抗病性测定结果表明,供试的10个南瓜品种中存在明显的抗病性差异,品种三星、红栗、甜栗表现为高抗;品种二星、日本、金钩、京域表现为抗病;品种光板、天然、红福表现为感病。品种抗病性与南瓜叶号叶绿素含量的高低和叶片气孔数量关系的研究结果表明,南瓜叶片中叶绿素的含量与南瓜品种对白粉病的抗性呈正相关,而气孔密度与抗病性呈负相关。     

2011—2020年河南省审定小麦品种抗病性评价

为了解河南省小麦品种抗病性水平,对2011年以来河南省审定的302个小麦品种进行条锈病、叶锈病、纹枯病、白粉病和赤霉病等5种病害的抗病性评价。结果表明,供试材料中具有抗病性的品种数量比例较小,未发现对叶锈病、白粉病和赤霉病表现高抗的品种;65%以上的品种对条锈病、叶锈病、白粉病和纹枯病表现中感,95%以上的品种对赤霉病表现高感;2个品种兼抗3种病害,35个品种兼抗2种病害,兼抗多种病害的品种比例少。今后河南省小麦育种中应加大抗病育种的研发力度。同时,做好小麦主要病害的防控。     

白粉菌侵染后田间小麦叶绿素含量与冠层光谱反射率的关系

 本文对白粉菌侵染后田间小麦叶片叶绿素含量与光谱反射率的关系进行了研究。用不同浓度的药液控制田间病害的发生梯度,于灌浆期对不同严重度小麦冠层的光谱反射率进行了测量,同时测定小麦叶绿素含量并调查病情指数,分析叶绿素含量与病情指数、冠层光谱反射率的关系。结果表明,药剂对叶绿素含量无显著影响;受白粉病危害后,小麦叶片叶绿素含量明显降低,抗性不同的品种之间下降速度存在差异,与病情指数之间也有极显著的相关性。绿光波段与叶绿素含量之间的相关性达到了显著水平;基于多波段建立的模型要优于单波段,可以利用绿光、红光波段的反射率估计叶绿素含量。红边参数与叶绿素含量之间也有较好的相关性,其中以红边面积的相关系数最大。     

棉花叶片中叶绿素、蜡质含量和叶片厚度与抗绿盲蝽的关系

为明确不同棉花品种(系)对绿盲蝽的抗性及其机制,通过网室内抗性鉴定和室内生化物质测定分析,系统研究了不同棉花品种(系)对绿盲蝽的抗性水平及棉花叶片中叶绿素和蜡质含量及叶片厚度与抗绿盲蝽的关系。结果表明,不同棉花品种对绿盲蝽抗性水平存在明显差异,其中石亚系1号综合抗性指数为179.49,达高抗水平。不同棉花品种(系)不同时期叶片中叶绿素和蜡质含量及叶片厚度均存在显著差异;苗期和蕾期棉花叶片中叶绿素含量和蕾期叶片中蜡质含量与其对绿盲蝽的抗性呈显著正相关;花铃期棉花叶片中叶绿素含量、苗期和花铃期叶片中蜡质含量及不同时期叶片厚度与其对绿盲蝽的抗性无明显相关性。     

陕西省小麦抗白粉病基因及新育成小麦品种(系)抗白粉病分析

为明确已知小麦抗白粉病基因载体品种以及2005—2007年陕西省新育成小麦品种(系)的抗病性,采集陕西关中不同地区小麦白粉病菌作为菌源,分年度在人工诱发病圃中对32份已知抗白粉病基因品种及578份新育成小麦品种(系)进行鉴定。结果表明,目前在陕西省仅Pm21、Pm4a、Pm5 6、Pm2 Talent及小黑麦具有优良的抗病性;Pm4b、Pm5(Mli)、Pm13、Pm19、Pm"Era"、Pm2 Mld的抗病性较弱;其它基因抗病性较差。新育成的小麦品种(系)中绝大部分对白粉病表现感病,苗期和成株期均抗病的材料仅27份,占4.67%,成株期抗病性的46份,占7.96%,其中,簇毛麦后代材料抗病性较高。     

湖北省小麦品种(系)对赤霉病、条锈病、白粉病和纹枯病的抗性评价

为了解湖北省小麦品种(系)的抗病性水平,对2001年以来湖北省审定的46个小麦品种和在湖北省进行区域试验的447份小麦品系进行赤霉病、条锈病、白粉病和纹枯病等4种主要病害的抗病性评价。结果表明:1)参试品系中有1份材料对赤霉病表现高抗,未发现对纹枯病表现高抗或免疫的材料;对赤霉病和纹枯病的平均抗性评价分值分别为14.30和3.49,介于中感和高感之间;对条锈病和白粉病的平均抗性评价分值分别为13.43和8.34,介于中抗和中感之间。2)审定品种的综合抗性水平不高,对条锈病的抗性评价分值为12.47,介于中抗和中感之间,对其他3种病害的抗性介于中感和高感之间;审定品种的单产呈增加趋势,株高在不断降低,生育期相应延长,综合抗病性也在增强。3)审定品种的综合抗病性与对条锈病抗性的相关系数最高,为0.738;对纹枯病的抗性与株高呈显著正相关,与单产呈显著负相关;对赤霉病的抗性与株高无显著相关。鉴于此,湖北省需加强抗病育种力度,同时应充分做好小麦病害的防控。     

BTH处理对甜瓜叶片活性氧代谢的诱导作用

为了明确活性氧（reactive oxygen species,ROS）代谢在甜瓜抗病性诱导中的作用,以抗白粉病甜瓜品种Tam Dew和感病品种卡拉克赛幼苗为材料,通过盆栽试验研究了苯丙噻二唑（BTH）喷雾或白粉菌接种后甜瓜叶片超氧阴离子（O2.-）产生速率、过氧化氢（H2O2）含量及超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、苯丙氨酸解氨酶（PAL）活性的变化。BTH处理或白粉菌接种均可诱导甜瓜叶片SOD、PAL活性升高,抑制CAT活性,导致叶组织O2.-产生速率和H2O2含量增加,BTH喷雾＋白粉菌接种比二者单独处理效果更好。结果表明,BTH处理后叶片O2.-产生速率提高和H2O2积累是甜瓜抗白粉病能力提高的重要机制,BTH通过诱导ROS代谢酶活性调节H2O2含量,且BTH诱导的甜瓜抗病性与品种的基础抗性有关。     

干旱条件下糜子叶片衰老与保护酶活性变化

在干旱棚栽培条件下以宁糜13号、内糜5号和晋糜4号糜子品种为材料,观测分析不同品种花后叶片叶绿素含量、保护酶活性(SOD、CAT、POD)以及丙二醛含量变化。结果表明,参试品种各功能叶片叶绿素含量及SOD、CAT、POD活性均在开花14 d后逐渐下降,MDA含量随着叶片的衰老而升高;参试品种叶片衰老的总体变化趋势一致,但衰老进程存在差异。与内糜5号和晋糜4号相比,宁糜13号叶绿素下降幅度小,各功能叶片衰老过程中SOD、CAT活性下降较慢,POD活性下降较快,MDA含量增加幅度小,叶片功能期长,衰老缓慢,有利于光合产物的积累;干旱条件下,叶绿素含量、过氧化氢酶CAT、超氧化物歧化酶SOD与单株产量呈正相关,而过氧化物酶POD、丙二醛MDA与单株产量呈负相关。     

不同花椒品种抗旱性比较研究

以3个花椒品种1年生实生苗为试材,采用盆栽试验,研究了干旱胁迫条件下3个品种叶片相对含水量、可溶性蛋白质含量、MDA含量、SOD、POD活性、叶绿素含量、净光合速率、茎生物量、根生物量、总生物量和根茎比的变化,利用隶属函数对其抗旱性进行了综合评价。结果表明,随干旱胁迫程度的增加,3个花椒品种叶片相对含水量均呈下降趋势;MDA含量、POD活性均呈上升趋势;可溶性蛋白含量先减少后增加;SOD活性、叶绿素含量、净光合速率季变化平均值先增加后下降;净光合速率季变化曲线呈单峰型或双峰型,但峰值出现的时间不同;茎生物量、根生物量和总生物量均呈下降趋势;豆椒根茎比降低,二红袍根茎比先降后升,大红袍根茎比上升。3个花椒品种抗旱性强弱排序为:豆椒二红袍大红袍。     

向日葵品种叶片组织结构与抗锈病的关系

向日葵锈病是向日葵的重要病害之一,在世界向日葵生产地区普遍发生,给向日葵产业带来巨大的经济损失。本研究通过比较向日葵抗、感锈病品种叶片组织结构的差异,以揭示此类病菌与寄主间的相互作用及其寄主抗病机理,研究结果表明：抗病品种叶片蜡质含量高于感病品种,且栅栏组织双层,排列整齐、紧密,可以抵抗病菌的侵入和扩展,而气孔密度与抗病性没有相关性。     

玉米灰斑病抗性机制中活性氧代谢的作用

研究了玉米灰斑病菌侵染四个抗病和感病的玉米品种时，叶片内部活性氧代谢酶及细胞过氧化产物含量的动力学变化。结果表明，抗、感病品种的SOD、CAT及POD酶活性在病茵侵染后都变化显著，抗病品种各酶活性变化幅度比感病品种大。叶片内过氧化产物MDA含量则相反，抗病品种沈试29在接种第13天时叶片MDA含量只为18．46nmol／g，而感病品种铁单9为23．14nmol／g，抗病品种比感病品种增加幅度小。说明活性氧代谢在植物抗病机制中起着重要作用，抗病品种对活性氧代谢的酶调节能力强，病菌侵染后细胞过氧化程度低，在痛菌侵染时活性氧清除酶活性最大增加值与发病程度呈显著正相关。     

Evaluation of screening methods and fruit composition in relation to anthracnose fruit rot resistance in blueberries

Anthracnose fruit rot is an important disease of blueberries, and losses are common in humid growing regions. Most commercial cultivars are susceptible and the disease is usually managed with fungicides. However, a few cultivars are considered resistant. The objectives of this study were to: (i) compare different inoculation techniques for anthracnose fruit rot resistance screening, (ii) screen ripe fruit from a range of blueberry cultivars using selected techniques, and (iii) investigate the role of fruit characteristics in anthracnose fruit rot resistance. The following inoculation methods were evaluated on ripe fruit of a susceptible and resistant cultivar using a conidial suspension: spray, droplet, and injection inoculation of whole fruit; and droplet inoculation of the open surface of cut fruit. All whole‐fruit inoculations yielded similar results. Despite the removal of the epidermis, resistance was also expressed in cut fruit but relatively fewer conidia were produced. The cut‐fruit assay required substantially less time and half the amount of fruit to accomplish than whole‐fruit assays. Detached ripe fruit from 24 cultivars in 2008 and 26 cultivars in 2009 were screened for resistance. Results from the cut‐fruit assay correlated best with published resistance ratings. To determine the possible role of fruit characteristics in resistance, fruit pH, titratable acidity, sugar content and firmness were regressed against various fruit rot resistance measures. Fruit rot resistance was positively correlated with sugar content. On defined media, mycelial growth was restricted as sugar concentration increased and pH decreased, suggesting that fruit composition may play a role in the resistance phenotype.     

The haustorial interface in a resistant interaction of Erysiphe pisi with Pisum sativum

The interface between Erysiphe pisi and pea cv. JI 1049 was studied at the ultrastructural and cytochemical levels and compared with those in two susceptible cultivars. Haustorial efficiencies, as indexed by the length of mycelium associated with each haustorium, and growth rates on the resistant and one susceptible cultivar were also compared.The interaction in the resistant cultivar differed from those in the susceptible cultivars in the following ways: (i) there was no contact between the host plasmalemma and the A neckband region; (ii) papillae were contiguous with the surface of the neck and thus were probably formed before haustoria and (iii) there appeared to be less polysaccharide in the extrahaustorial membrane. The extrahaustorial membrane in the resistant cultivar lacked ATPase activity, whereas the rest of the host plasmamembrane had normal activity.Each haustorium supported a significantly greater total hyphal length in the resistant than in the susceptible cultivars. Growth rates of superficial hyphae were very similar on the susceptible and resistant cultivars but there was a delay in the onset on hyphal growth on the resistant cultivar which correlated with the previously reported delay in formation of the first haustorium. In contrast to hyphal growth rates, the rate of haustorium production was significantly less in the resistant cultivar. It is proposed that resistance in cv. JI 1049 operates at the stages prior to haustorium formation, similarly to that in some non-host and partial resistance systems. Once formed, however, the function of the haustorium seems to be unimpaired, despite the observed interfacial differences.     

Susceptibility of Broccoli Cultivars to Bacterial Head Rot: In Vitro Screening and the Role of Head Morphology in Resistance

Head rot is a major disease of broccoli caused by the soft rot pathogens Pseudomonas fluorescens and Erwinia carotovora. Two in vitro pathogenicity tests were evaluated as a methods to identify broccoli cultivars susceptible or resistant to bacterial head rot. One test used mature heads excised from the plant and inoculated with squares of cotton lint which had been soaked in a bacterial suspension. The other test involved stab-inoculating axenically grown seedlings. With the excised head test, susceptible cultivars showed a black soft rot, whilst less susceptible or moderately resistant cultivars showed only watersoaking, or browning and slight softening of the tissue. No cultivar was completely resistant. Ten cultivars were tested, and their susceptibility ratings corresponded with previously recorded field data, with one exception. This laboratory test could be used to screen for susceptibility to head rot in broccoli breeding programmes. The seedling test distinguished differences in aggressiveness among bacterial isolates but not cultivar susceptibility. Increasing head size correlated negatively with disease resistance. Head shape, i.e. cultivars which showed a domed shape rather than a flat shape, was positively correlated with disease resistance. Thus small domed heads are more resistant to head rot than large flat heads. Other morphological characteristics, viz. floret prominence and number, and sepal stomatal number were not correlated with host resistance.     

小麦品种混种对白粉病的调控及其对部分产量性状及蛋白质含量的影响

对品种混合种植控制小麦白粉病的效果以及对小麦穗重、千粒重、蛋白质等指标的影响进行了研究,为混合种植控制白粉病提供理论依据和品种组合。在对37个小麦品种进行SSR多样性分析的基础上,选用8个生产品种（后备品种）,按品种数3、4、5、6、8进行组合,在田间以随机区组设计种植混播组合和单播小区,人工接种白粉菌,比较各小区中小麦白粉病的AUDPC值、穗重、千粒重和粗蛋白差异。结果表明,8个品种亲缘关系较远;4品种混种时AUDPC最小,穗重最重。26个品种混种组合中有防治效果的组合占到73.08%,相对防效为1.23%~56.65%;混种未对穗重和粗蛋白含量造成负面影响。品种多样性种植可以用做调控小麦白粉病的一项措施。     

不同百合品种对百合灰霉病的抗病性鉴定

为明确不同百合品种对灰霉病的抗病能力,本试验采用离体叶片菌丝块接种和田间孢子液喷雾2种方法测定了百合7个不同品种对百合灰霉病的抗病性。离体测定结果表明,供试的7个品种对百合灰霉病的抗病性存在显著差异,其中‘法兰西’和‘罗蒂娜’为高感品种,‘康斯坦萨’和‘索邦’为高抗品种,‘马可波罗’、‘提拔’和‘西伯利亚’为中抗品种;田间接种发病的测定结果除‘西伯利亚’为高抗品种外其余结果与离体接种结果一致;离体接种和田间接种发病情况的系统调查分析得知,感病品种‘法兰西’和‘罗蒂娜’发病早,病情发展速度快,病情指数高;‘提拔’、‘康斯坦萨’、‘西伯利亚’和‘索邦’等抗病品种发病晚,病情发展缓慢,病情指数低;随着品种抗病性的增强,发病速度和病情指数逐渐降低。     

Variation in susceptibility of lettuce cultivars to fusarium wilt caused by Fusarium oxysporum f.sp. lactucae

Lettuce cultivars adapted to Californian growing conditions were screened for resistance to fusarium wilt caused by Fusarium oxysporum f.sp. lactucae in order to determine if differences in susceptibility among currently grown cultivars might contribute to management of this disease. Based on a preliminary evaluation of 46 cultivars, eight that were among the most resistant of their horticultural type (iceberg, romaine or leaf) were selected for further testing. The relative susceptibility of these cultivars was assessed by: (i) root-dip inoculation, (ii) sowing seeds into infested potting mix and (iii) transplanting seedlings into an infested field. Evaluations of disease severity showed that both methods (i) and (ii) produced cultivar rankings that were significantly correlated with rankings from field trials [method (iii)]. Two romaine and two leaf cultivars were highly resistant to fusarium wilt (mean disease severity rating of ≤1·3 on a 1–4 scale) under all test conditions. Other romaine and leaf cultivars, however, were highly susceptible in root–dip tests, so there was no consistent association between cultivar type and susceptibility to fusarium wilt. Likewise, there was considerable variation in susceptibility to wilt among iceberg cultivars, but all were significantly more susceptible than the most resistant romaine and leaf cultivars.     

品种布局防治小麦条锈病的模拟研究

 用小麦条锈病大区流行模型PANCRIN进行的模拟试验结果指出:抗病品种的合理布局能有效地延缓和减轻抗病性丧失,但其效果易受品种面积、流行速率和越夏区面积浮动的影响。布局策略上首先要按照小麦条锈病菌越夏途径中不同成熟期的麦田进行细致的布局,也就是布局要和"打越夏"结合,效果才更显著。其次要控制每个抗病品种的面积而增多抗病品种的数目,在所用模型规定的条件下,每一抗病品种的种植面积百分比不可超过15%,抗病品种总数争取≥ 6个。此外,要尽量压缩感病品种面积,减少大区流行菌量,感病品种面积最好不超过10%。流行系统的定量控制是个极其复杂的问题,因此上述初步结果只能供作研究参考,还不能视为应用指标。合理布局的设计应以深入掌握越夏规律为基础,这需要进一步开展有关研究。目前情况下,生产上尽量增多抗病品种数目,只要上下游品种雷同的不多,也能多少延长抗病品种的使用年限。     

猕猴桃品种酚类物质及可溶性蛋白含量与抗溃疡病的关系

以安徽省猕猴桃主栽品种金魁、早鲜、魁蜜、华美2号、秦美、金丰为研究对象,于展叶孕蕾期分别取发病的枝条、叶片,以未发病健株的相应组织为对照,分析枝条、叶片中酚类物质和可溶性蛋白的含量变化。结果表明：抗病品种健株枝条、叶片中可溶性蛋白含量显著高于易感病品种,说明枝条中可溶性蛋白含量与品种抗性成正相关。自然发病后,感病品种枝条中可溶性蛋白含量增加,抗病品种可溶性蛋白含量降低。抗病品种健枝条、叶片中酚类物质含量高于易感病品种的健枝、叶,发病后抗感品种酚类物质含量都增加。