梨种质资源对黑星病抗性评价

采用人工接种黑星病菌的方法,对国家果树种质兴城梨资源圃保存的197份梨种质资源进行了抗病性鉴定,结果表明:不同梨种类发病率差异很大,其中白梨和砂梨最易感病,秋子梨和种间杂交选育品种较易感病,新疆梨较抗病,西洋梨最抗病;对病情指数在各梨种类分布进行了分析;在白梨、砂梨、秋子等各系统分别筛选出黄鸡腿、甩梨、酸梨、锦香等一批抗病资源;对田间自然感病与人工接种感病结果进行了比较。     

梨黑星菌粗毒素对抗病和感病梨离体叶片生理特性的影响

以不同抗病性梨品种为材料,研究了梨黑星菌粗毒素对梨离体叶片的过氧化物酶(POD)活性、苯丙氨酸解氨酶(PAL)活性、丙二醛(MDA)含量、细胞膜相对透性以及叶绿素含量变化的影响.研究表明,毒素接种后抗病和感病品种叶片的POD和PAL活性、MDA含量和相对电导率均呈上升趋势,其间会有1个或2个峰值出现,且抗病品种叶片的POD和PAL活性高于感病品种,而细胞内MDA含量和相对电导率增加比率低于感病品种;同时,毒素使梨离体叶片的叶绿素、类胡萝卜素含量下降,且感病品种的下降幅度大于抗病品种.总之,梨离体叶片POD和PAL的活性变化与梨品种抗病性呈正相关,叶片MDA含量和相对电导率变化与梨品种抗病性呈负相关,抗病品种离体叶片对毒素的毒害有更强的抵抗力.     

珍珠柴粗提物对13种植物病原菌的抑制活性

以生长速率法测定了珍珠柴7种溶剂粗提物对棉花黄萎病菌V991、棉花黄萎病菌V43-1、棉花枯萎病菌、茄子黄萎病菌、稻曲病病菌、苹果黑星病菌、番茄枯萎病菌、番茄叶霉病菌、黄瓜黑星病菌、西瓜炭疽病菌、芦笋茎枯病菌、扩展青霉和梨黑斑病菌13种植物病原菌的抑制活性。结果表明,不同溶剂粗提物的抑菌活性差异很大,某些溶剂粗提物对个别病菌表现出较强的抑制作用,如水粗提物对棉花黄萎病菌V991,石油醚粗提物对苹果黑星病菌的抑制率分别达100%和91.89%;有的溶剂粗提物的病菌抑制作用较弱,如二氯甲烷粗提物对13种病菌的抑菌率均较低;有些还表现出一定的促进生长作用,如甲醇粗提物对梨黑斑病菌表现为明显的促进生长作用。     

黄瓜抗黑星病不同基因源的遗传分析

基于苗期人工接种鉴定结果,获得2份抗黑星病黄瓜材料(HX1,Cucumis sativus var.sativus,DI=5;HX5,C.sativusvar.xishuangbannesis,DI=38.7)和1份感病材料(HX8,C.sativus var.sativus,DI=80)。利用上述3份材料构建了2个组合(HX1×HX8,HX5×HX8)的6世代群体(P1、P2、F1、F2、B1和B2),并分别进行黑星病苗期人工接种鉴定。采用主基因+多基因联合遗传分析方法进行遗传分析,结果表明2份材料抗黑星病的遗传规律不同。组合HX1×HX8的F1单株表现为抗病,而组合HX5×HX8的F1单株基本表现为感病。HX1对黑星病的抗性符合两对加性-显性-上位性主基因+加性-显性多基因混合遗传模型(E_1模型),HX5的抗性遗传符合加性-显性多基因模型(C模型)。在组合HX1×HX8中,两对主基因的加性效应均大于显性效应,B1、B2和F2群体的主基因遗传率分别为72.51%、98.19%和96.91%,多基因遗传率均为0,表明HX1对黑星病的抗性以主基因遗传为主;HX5对黑星病的抗性遗传以多基因的显性效应为主。     

水晶梨病虫害防治预测模型

[目的]为提高水晶梨病虫害防治工作效率,进一步提升病虫害的预测效果和精度。[方法]深入研究了灰色模型(GM),利用GM对水晶梨环境因子数据进行建模得到病虫害预测公式,通过差分方程推导出时间响应式和参数估计,建立了优化初始值的灰色模型(OIVGM),将OIVGM与BP神经网络预测模型(BP)进行组合,建立了优化初始值的灰色BP神经网络预测组合模型(OIVGM-BP)。[结果]通过单位根检验法测量模型的稳定性,OIVGM-BP一阶差分处理后,T统计量(-5.487654)小于5%临界值(-2.878073),数据序列表明平稳,OIVGM-BP可以稳定进行预测。通过白噪声检验方法测量OIVGM-BP的适应性,OIVGM-BP的残差P值从第二阶开始,均大于0.05,说明OIVGM-BP的适应性较好,各阶均通过了白噪声检验。LRM、GM、TSM、BP、OIVGM-BP对梨锈病、白粉病、腐烂病、梨黄粉蚜、梨二叉蚜、梨木虱6种病虫害的预测准确率的平均值分别为70.81%、70.09%、69.74%、65.64%、83.01%,OIVGM-BP的预测准确率优于其他4种预测模型。[结论]OIVGM-BP能够对水晶梨病虫害进行有效预测,能够更好地指导农业生产。     

秦冠苹果品种对苹果黑星病的组织学抗性研究

为揭示苹果抗病品种秦冠在组织细胞学水平上抗苹果黑星病的特征,本研究采用扫描和透射电镜技术,将苹果黑星菌Venturia inaequalis接种侵染寄主后,系统观察抗病品种秦冠和感病品种嘎啦的叶片组织和细胞结构变化。扫描电镜观察结果表明,黑星菌分生孢子悬浮液接种秦冠和嘎啦叶片48 h后,病菌沿叶脉生长扩展,其菌丝可从叶片气孔或直接侵入。透射电镜观察结果表明,秦冠叶片的角质层厚度明显高于嘎啦,其中秦冠角质层平均厚度为1.75 μm,嘎啦为1.06 μm。透射电镜观察结果表明,黑星菌菌丝在寄主叶肉细胞间扩展,导致嘎啦栅栏组织细胞萎缩,排列松散,叶绿体变形受损,细胞内出现较大淀粉粒和胞内物质外渗流失,并在后期发展成大量细胞坏死;而秦冠虽症状类似,但受损程度明显小于嘎啦。以上结果表明,秦冠在组织细胞学上对苹果黑星病具有抗侵染、抗扩展和延缓病程发展的作用,可作为苹果黑星病抗性育种材料加以利用。     

壳寡糖诱导黄瓜抗黄瓜黑星病的初步研究

本文研究了壳寡糖诱导黄瓜对黑星病的抗性作用。利用6 mg/mL壳寡糖溶液对苗期黄瓜诱导,进行病情调查统计及测定处理前后黄瓜叶片的主要防御酶系———苯丙氨酸解氨酶,过氧化物酶,多酚氧化酶,超氧化物歧化酶,过氧化氢酶的活性变化。结果显示,壳寡糖对黄瓜黑星病在10 d和17 d的诱抗效果分别为60.25%和47.59%,且作为诱导因子可显著提高黄瓜叶片内苯丙氨酸解氨酶(PAL)活性,过氧化物酶(POD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)活性也有所提高,但叶片内过氧化氢酶(CAT)活性无较明显变化。研究结果表明壳寡糖对黄瓜抗黑星病产生诱导作用,为研究壳寡糖作为新型生物农药提供了依据。     

吹扫捕集-热脱附-气质联用法分析竹醋蒸馏液成分及其水果采后防腐研究

采用吹扫捕集-热脱附-气相色谱质谱(PT-TD-GC-MS)法,比较分析了竹醋原液及竹醋蒸馏液的化学组分,在离体和活体条件下评价竹醋蒸馏液对植物病原真菌的抑制活性。结果表明,竹醋原液中检出挥发性成分的数量为24种,竹醋蒸馏液中检出挥发性成分的数量为26种。2种竹醋液中相对含量≥2%的共有成分为:乙酸甲酯、乙酸、糠醛、苯酚、愈创木酚。离体抑菌结果表明,竹醋原液和竹醋蒸馏液均具有明显的抑制真菌效果,竹醋蒸馏液对番茄灰霉菌、苹果炭疽菌、小麦赤霉菌和梨黑星菌的半抑制浓度(IC_(50))值(处理48 h后)分别为:18. 01、16. 04、15. 70和11. 24 mL/L。活体抑菌结果表明,接种了苹果炭疽菌和梨黑星菌的苹果和梨,经竹醋蒸馏液浸渍处理后表现出了明显的抑菌效果,防治效果分别为72. 18%(苹果)和79. 76%(梨)。本研究旨在为竹醋蒸馏液在果蔬防腐剂产品的研发提供基础。     

黄瓜抗黑星病相关基因的差异表达分析

以抗黑星病黄瓜材料HX1为试材,接种黑星病菌（Cladosporium cucumerinum）2h、8h、20h、32h和72h的叶片作为试验方（Tester）,相应的未接种叶片作为对照方（Driver）,利用SSH技术,构建了黑星病菌侵染初期的正向和反向cDNA-SSH文库。用巢式引物PCR检测插入片段,获得了200个阳性克隆,通过测序,除去重复序列,共得到105个Unique ESTs。与非冗余蛋白数据库进行BLASTx比对,结果显示,17条ESTs未找到同源序列,88条非重复序列和已知基因的同源性较高,占全部ESTs序列的83.8%,其中86条ESTs与非冗余蛋白数据库已知功能的蛋白具有高度的相似性。结合高密度点阵膜杂交差异筛选,阳性率为75.0%。经初步分析这些序列的功能,差异表达的ESTs功能涉及能量和基础代谢、信号转导、蛋白和核酸代谢、光合作用及逆境中特异表达的基因等方面。为研究黄瓜抗黑星病基因提供了依据。     

安徽梨主栽品种对锈病的抗性差异及其空间格局的数学分析

安徽梨主栽品种对锈病的抗性差异分析结果显示,最为感病的是砀山酥梨,其次为明月、大青皮．莱阳梨居中．较抗病的是开桦梨和康德梨．感病品种锈病在大田中呈聚集分布．抗病品种开桦梨也属聚集分布,而康德梨和莱阳梨锈病在田间为均匀分布．树上病情分布格局分析结果显示,无论感病或抗病品种均为聚集分布．     

A new pear scab resistance gene Rvp1 from the European pear cultivar ‘Navara’ maps in a genomic region syntenic to an apple scab resistance gene cluster on linkage group 2

Scab, caused by the ascomycete fungus Venturia pirina, leads to severe damage on European pear varieties resulting in a loss of commercial value and requiring frequent use of fungicides. Identifying scab resistance genes, developing molecular markers linked to these genes and establishing marker-assisted selection would be an effective way to improve European pear breeding for scab resistance. Most of the European pear cultivars (Pyrus communis) are currently reported to be sensitive. The pear cultivar ‘Navara’ was shown to carry a major scab resistance gene whose phenotypic expression in seedling progenies was a typical stellate necrosis symptom. The resistance gene was called Rvp1, for resistance to V. pirina, and was mapped on linkage group 2 of the pear genome close to microsatellite marker CH02b10. This genomic region is known to carry a cluster of scab resistance genes in apple indicating a first functional synteny for scab resistance between apple and pear.     

Formation and Development of Pseudothecia of Venturia nashicola

Conidia are believed to be the main source of primary inoculum for pear scab, caused by Venturia nashicola, in northern China. Experiments were conducted to investigate the development and potential role of V. nashicola ascospores in northern China. Leaves with pear scab lesions were collected from commercial orchards in November 2003 and 2004 to monitor pseudothecia formation under various environments. Pseudothecium production was shown to occur readily in northern China. The key requirement for pseudothecium production is the occurrence of rain during the winter and early spring, although the exact timing of these rain events appeared not to affect their development. Excess water may lead to the accelerated leaf decay and hence lead to production of fewer pseudothecia. More than 80% scabbed leaves, placed in a pear orchard, produced pseudothecia. Leaves with only non‐sporulating scab lesions in autumn were also able to produce a large number of pseudothecia. Both airborne ascospores and conidia of V. nashicola were caught in a pear orchard. Most ascospores were released by late‐May, a month after pear blossom. These results suggest that ascospores may play an important role in the early stage of pear scab epidemics in spring in northern China.     

Epidemiological research of twig scab on pear as basis for a rational and ecological disease management

Scab is one of the key parasites in fruit growth. In favourable weather conditions for the pathogen, a complete harvest can be destroyed if no control measurements are undertaken. The scab fungi on pear and apple are two distinct species. They have, however, a similar biological cycle. Despite the similarities, there are also clear differences and these differences are significant for the control of the pathogen. Pear scab does not only infect fruit and leaves as apple scab does, but also infects twigs. Especially in organic fruit growing, twig scab is a big problem. Once twig scab occurs, it seems to be impossible to get rid of scab in these orchards. The only possibility for the fruit grower in this case is a strict spraying schedule to ensure no further spread of the infection. The main goal of the project is a thorough study of the pear scab fungi (biology, sensitivity of different plant parts and cultivars, dispersal of the fungi and infection conditions, the pathogenicity and characterization of different biotypes) to unravel the life of the fungi and to develop a better control strategy. A better control strategy means a reduced fungicide use and a reduction of fungicide residue on the fruits at harvest, without a reduction of the quality of the fruits and cost effectiveness for the fruit grower. Special attention in the project goes to the role and the control of twig scab. The first results of this project will be shown.     

Genetic mapping of the pear scab resistance gene Vnk of Japanese pear cultivar Kinchaku

Pear scab (caused by Venturia nashicola) is one of the most harmful diseases of pears, especially Japanese and Chinese pear species. The molecular identification and early selection of resistant plants could greatly improve pear breeding. We have identified the position of the scab resistance gene, designated Vnk in an indigenous Japanese pear cultivar Kinchaku, within the pear genome by using simple sequence repeat (SSR) markers derived from pear and apple. The position of Vnk was identified in the central region of linkage group 1 of Kinchaku. Several amplified fragment length polymorphism (AFLP) markers linked to Vnk were obtained by bulked segregant analysis. Among them, the AFLP marker closest to Vnk was converted into a sequence tagged site (STS) marker. Four random amplified polymorphic DNA (RAPD) markers previously found to be loosely associated with Vnk (Iketani et al. 2001) were successfully converted into STS markers. Six markers (one SSR Hi02c07 and five STSs converted from AFLP and RAPD) showed tight linkages to Vnk, being mapped with distances ranging from 2.4 to 12.4 cM. The SSR CH-Vf2, which was isolated from a BAC clone of the contig containing the apple scab gene Vf, was mapped at the bottom of linkage group 1 in Kinchaku, suggesting that the Vnk and Vf loci are located in different genomic regions of the same homologous linkage group.     

Pear scab resistance QTLs via a European pear (Pyrus communis) linkage map

Pear scab caused by Venturia pyrina is an economically important disease throughout the world and can cause severe crop loss in susceptible cultivars. The varying range of susceptibility to pear scab in F1 populations has made it possible to identify quantitative trait loci (QTLs). Ninety-five seedlings derived from the cross ‘Abbè Fétel’ (AF) × ‘Max Red Bartlett’ (MRB) were evaluated for scab resistance in greenhouse tests, with 39% being classified as resistant, 33 as moderately susceptible and 28 as highly susceptible. Amplified fragment length polymorphisms (157) and simple sequence repeats (41) were used to construct two maps, one of 908.1 cM (AF) and the other of 879.8 cM (MRB). The analysis of the resistance data collected made it possible to identify two major QTLs on linkage groups 3 and 7 associated with resistance to V. pyrina. Both QTLs explained 88% of the phenotypic variance and the log of odds values were higher than 10, suggesting the involvement of two major genes in pear scab resistance. L. Pierantoni and L. Dondini have contributed equally to this work.     

马铃薯品种(系)资源的疮痂病抗性鉴定

为了筛选出高抗疮痂病马铃薯品种(系),本研究以36份马铃薯品种(系)资源为材料,分别在南宁市和玉林市种植,通过调查发病率和病情指数,用隶属函数法对36份材料的疮痂病抗性田间自然病圃鉴定结果进行分析。结果表明,发病率(x)和病情指数(y)呈正态分布,y是x的指数函数;明确了其中有2份高抗疮痂病马铃薯品种(系)和1份高感疮痂病马铃薯材料,田间种植法与人工接种鉴定结果基本一致,为马铃薯疮痂病情预测和抗疮痂病育种提供了参考。     

梨果实表面积新测算方法的建立

基于对梨果形的分析,提出用随圆及线性方程描述梨果实,由这些方程推导出测算梨果袂表面积的新公式的新方法,新方法测量简便快速,只需一把游标卡尺即可,测出果实横径、纵径、梗端果宽、萼洼深及最大横径与果项间的长度,即可用新公式计算出果实表面积,在两个品种上对新公式测算精度进行检验,其平均测算误差分别为１．８６％和２．５２％,说明用新方法可相当准确地测算梨果实表面积。