Screening of Chemical Control for Potato Blight

To screen chemicals for controlling potato blight effectively, randomized block experiment was adopted, the control efficiency of five chemicals for Carbendazim, Metalaxyl, Dithane mancozeb, Curzate, Cymoxanil mancozeb was explored. The results showed that the efficiency of Metalaxyl was much better than that of other conventional chemicals in controlling potato blight, up to 70.59% ; the mean control efficiency of Curzate and Cymoxanil mancozeb was 68.76% and 67.05% ; the control efficiency of Carbendazim was lower, 55.76%. Big and middle tuber rate, tuber weight per hole, plot yield, unit area yield of potatoes in Metalaxyl treatment were the highest, 78.05%, 437.24 g/hole, 34.0 kg/21.6 m2 and 15 748.61 kg/hm2, 49.12% higher than the control yield. The indexes of potatoes in Cymoxanil mancozeb treatment were the second highest, 73.33%, 385.31 g/hole, 32.8 kg/21.6 m2 and 15 192.78 kg/hm2, 43.86% higher than the control yield.

Potato late blight caused by Phytophthora infestans:From molecular interactions to integrated management strategies

Over 170 years after the infamous Irish Potato Famine,potato late blight(PLB)caused by Phytophthora infestans remains the single most devastating disease of global potato production,causing up to 10 billion USD in yield loss and management costs.Through decades of research,growers and agronomists in the field as well as laboratory scientists have made significant progress in understanding the molecular pathogenesis process of this critical pathosystem and effective management strategies to control PLB.Yet,the need to feed an ever-increasing global population under changing climate demands continued improvement in efficient and sustainable PLB management schemes that can be implemented across a broad economic spectrum.In this review,we briefly summarize the current understanding of the molecular interaction between P.infestans and its host plants,highlight the current integrated pest management strategy to control PLB on local and continental scales,and discuss the potential of further improvement of sustainable PLB control through genetic enhancement of crop resistance and emerging crop protection technologies.

Control Efficacy of 45% Propamocarb·Denamidone SC against Potato Late Blight

The effects of different doses of 45% pmpamoearb · fenamidone SC on potato late blight were studied in the paper. The results showed that the overall control effect of 45% propamocarb · fenamidone SC against potato late blight on the 14^th day after the third spraying were 67.64% -83.78%. The yield of potato reached 19 972.5 -23 302.5 kg/hm^2, with higher marketable tuber rate and lower rotten tuber rate. With the increase in fungicide dose, the difference in control effect against late blight was significant, but the yield-increasing effect on potatoes was not significant. The appropriate application dosage of 45% propamecarb · fenamidone SC were 450 -675 g/hm^2.

Occurrence and Damage and Pathogene of Potato Early Blight in Winter in Yunnan Province,China

[Objectives]The paper was to understand the species and pathogenicity of the pathogen causing potato early blight in winter.[Methods]The occurrence of potato early blight was investigated in 5 winter potato growing areas in Yunnan Province.The disease samples were collected from two locations(Zhutang Village and Zhanai Village,Pu'er City)where the occurrence of early blight was severe.The pathogen was isolated and purified in laboratory and identified by morphological characteristics and phylogenetic analysis of ITS gene sequence.And it was further verified via re-inoculation by Koch's rules.The growth characteristics and pathogenicity of isolates in different seasons were analyzed with 4 strains of Alternaria isolated in spring(EYZ,EYAX,TA1 and TAC)as controls.[Results]Early blight occurred in varying degrees in the 5 winter potato growing areas,and the incidence of early blight was up to 100%in some plots in Lancang County,Pu'er City.A total of 35 strains of Alternaria were isolated from plots with high incidence,which were divided into two types according to colony morphology.The first type was round colonies with smooth edges and gray white fronts,and the second type was round colonies with rough edges and gray black fronts.Three strains LC1,LC2,LC3 of the first type and two strains ZT3 and ZT8 of the second type were selected and identified as Alternaria alternata through morphological and molecular identification.Re-inoculation test further confirmed that the pathogen was A.alternata.Meantime,it was found that the growth rate of colonies isolated in winter was relatively slow,and there was no significant difference between the pathogenicity of LC1 and TA1,but the pathogenicity of strains isolated in winter was generally higher than that isolated in spring.[Conclusions]It is confirmed that the pathogen causing potato early blight in winter is A.alternata in Yunnan Province.The results will lay a foundation for the research of pathogenesis,occurrence regularity and disease control of A.alternata in winter potato.

<i>In vitro</i>and greenhouse evaluation for resistance to early blight of potato isolated from <i>Alternaria alternata</i>

Early blight of potato is caused by the fungus Alternaria alternata, one of the most destructive foliar diseases, especially in hot climates under irrigation. In this study, the virus free potato seedlings were obtained from the National Plant Gene Bank of Iran and were inoculated in vitro with a culture filtrate of A. alternate. The leaflets received a 1000-μl droplet of the A. alternata culture filtrate and were inoculated by spraying with a suspension of 105 conidia/ml of isolate A. alternata in the greenhouse method. The experimental design was a completely randomized design (CRD) with three replications and seven genotypes, which have been infected with the two leaves of each iteration. In vitro selection of fungal isolates of A. alternata, chlorotic and necrotic symptoms began 1 to 2 days after inoculation, but the assessment of greenhouse symptoms appeared 6-10 days after inoculation. The area under the disease progress curve values were presented by analysis of variance (ANOVA), and they were compared using Duncan’s test (a = 0.01%). In both methods, there was a significant difference between the potato genotypes (P In vitro selection and evaluation greenhouse, Casmos were resistant to at least figure and Marfona genotype had the highest resistance.

Population Improvement of Resistance to Late Blight in Tetraploid Potato:A Case Study in Combination with AFLP Marker Assisted Background Selection

Cultivated potato with high level of horizontal resistance against late blight is one of the most important goals of potato breeding.The recurrent selection has been adopted to increase the level of potato horizontal resistance and a B3C1 population without R1-R11 dominant genes has been released by the International Potato Center at the short-day condition of Peru.The present research was carried out to further improve the resistance and the agronomic traits of B3C1 population under long-day condition of Hubei,China,with maximized retention of its genetic diversity.Twenty-seven individual clones of B3C1 were used to generate population B3C2 by in-population crossing with the bulk pollens aiming to elevate the frequency of late blight resistance genotypes and to improve the adaptation to local long-day conditions.The late blight resistance and the main agronomic traits including the maturity,the plant characters and the tuber traits were evaluated for the foreground selection in three years,by which 130 pedigrees were maintained as the basic population of B3C2 for further selection.A total of 312 polymorphic loci detected by 9 AFLP marker combinations were used to monitor the genetic diversity of the populations for the background selection.The B3C2 population of 51 clones was finally selected,of which the frequency of resistant genotypes increased by 23.8% points and the genetic diversity was maintained by about 96% as referred to B3C1.Our results strongly suggested that combination of the foreground selection for target traits and the background selection for the genetic diversity is an efficient strategy in the recurrent selection of tetraploid potato to improve quantitative traits.

Assessment on early blight of potato in order to compare the two methods<i>in vitro </i>using pathogenic fungi <i>Alternaria solani</i>

Potato (Solanum tuberosum) early blight, caused by Alternaria solani is one of the most destructive fungal foliar diseases. This research was done in order to study methods comparison of evaluation by culture filtrate of A. solani in in vitro condition for selecting resistance cultivars to early blight. Plantlets of potato viruse free were obtained from the National plant gene bank of Iran, and were inoculated in vitro methods with a culture filtrate of A. solani. In in vitro selection by droplet of culture filtrate method, leaflet received a 10 μl droplet of the A. solani culture filtrate and in in vitro selection by direct using of culture filtrate method, plantlets were placed in test tubes that include 5 μl A. solani culture filtrate. The experimental design was factorial on basis of completely randomized design (CRD) with two factors, three replications and six genotypes. During droplet method assay, the A. solani symptoms appeared 1 - 2 days until 6 days and during direct method they appeared 2 - 3 days until 6 days. The AUDPC values were submitted to the analysis of varience (ANOVA) and AUDPC means were compared by using Duncan test (α = 0.01%). In each method, significant difference among potato cultivars was observed for disease to early blight (p < 0.01). Results show that casmos cultivar is susceptible for resistance to early blight and in vitro methods experiment had the same result.

Efficacy of Some Botanical Extracts on the Control of Late Blight Disease in Experimental Potato Field

Late blight caused by Phytophthora infestans (Mont.) De Bary is the most devastating disease of potato. This study was carried out to evaluate the efficacy of ten botanical extracts against the late blight disease incidence and severity in experimental potato field at University of Rajshahi, Bangladesh during 2019-2020. Crude aqueous extract of leaves of Syzygium cumini, Psidium guajava, Eucalyptus globusus, Carica papaya and Lawsonia inermis;fruits of Terminalia bellirica, T. chebula and Piper nigrum;flower buds of Syzygium aromaticum and cloves of Allium sativum were used at 5% (w/v) concentration for evaluation. Out of ten botanicals, Syzygium cumini leaves extract was found most effective in controlling the late blight disease incidence and severity up to 66 DAS (days after sowing) and increased the potato yield by 71.29% compare to untreated control. The efficacy of Lawsonia inermis extract against late blight disease was found promising and increased the potato yield by 48.51%. Other four botanical extracts (Terminalia chebula, Piper nigrum, Syzygium aromaticum and Carica papaya) showed moderate efficacy against the incidence and severity of late blight disease, and increased 30% more potato yield compare to control. These results suggest that botanical extract of Syzygium cumini has a great potential as an alternative of chemical fungicides to control the late blight disease of potato in eco-friendly way.

117份高抗晚疫病马铃薯种质资源遗传多样性分析

以117份高抗晚疫病马铃薯种质资源为试验材料,通过遗传多样性指数、变异系数及聚类分析等方法,对117份试验材料的26个性状进行分析。结果表明,20个质量性状的遗传多样性指数变化范围为0.35~1.61,6个数量性状变异系数大小排序依次为:主茎数>块茎产量>株高>干物质含量>茎粗>淀粉含量,遗传多样性指数变化范围为0.99~1.50。通过聚类分析,117份试验材料被划分为4类,第Ⅰ类材料多样性丰富,整体性状表现优良,比较符合现有栽培品种的性状特点;第Ⅱ类材料平均产量较高,聚合了我国主栽的4个高抗晚疫病马铃薯品种,可作为晚疫病抗性育种亲本;第Ⅲ类材料主茎数较多,植株整体表现为短日照类型,可作为抗性育种的抗原材料;第Ⅳ类材料包含4份资源,产量最高,可直接用于生产和育种亲本。对117份材料进行R8分子标记检测,其中104份资源含有R8基因,可作为晚疫病抗性基因聚合育种的基础材料。

卷积神经网络结合改进光谱处理方法用于马铃薯病害检测

针对马铃薯早疫病不同染病时期光谱数据受到杂散光和噪声等因素的干扰,以及波段数众多、数据量大且谱带复杂会对光谱的定量和定性分析产生不利影响,研究9种光谱预处理方法,结合实验结果,将预处理方法进行排列组合,扩展改进为16种光谱预处理方法,并与连续投影算法、竞争自适应重加权算法和遗传算法3种特征波段提取方法进行组合得到64种光谱处理方法对原始光谱数据进行优化处理。在卷积神经网络(CNN)分类模型中,大部分经过光谱处理方法优化后的光谱数据分类精度相比原始数据的总体分类精度86.67%明显提高,其中12种光谱处理方法的分类精度达到100%,实现对马铃薯早疫病不同染病时期的理想分类。为进一步对马铃薯早疫病不同染病时期进行定量分析,将经过光谱处理方法处理后的光谱数据使用构建的CNN定量估算模型进行定量分析,结果表明,光谱预处理在优化数据的同时,也会损失数据中对目标变量有用的光谱信息,从而导致经过光谱分析方法处理后的数据结果相对于原始光谱数据的R^(2)和RMSE会出现下降的结果,通过研究使用的融合光谱处理方法对原始光谱数据优化能够进一步提升模型性能,其中基于均值中心化、多元散射校正、移动平均平滑相结合的光谱处理方法的CNN定量估算模型取得了最好的结果,其R^(2)为1说明估算的马铃薯早疫病不同染病时期和实际值拟合程度达到100%拟合,其RMSE仅为0.001 1,表明马铃薯早疫病不同染病时期的估算值与真实值之间的偏差接近0,说明该模型能够对马铃薯早疫病不同染病时期进行完美预测。结果表明提出的CNN能够对马铃薯早疫病不同染病时期进行有效地分类检测和定量分析,将各类预处理和特征波段提取方法按优化目的进行有效组合能够有效提高建模效果,为农作物病害无损、精准、智能化检测提供理论和技术支持。

基于CARAH预警系统对8种马铃薯晚疫病新型杀菌剂的防效评估

[目的]筛选马铃薯晚疫病防控新型高效绿色杀菌剂及生物农药,为科学合理使用高效杀菌剂开展马铃薯晚疫病绿色防控提供指导。[方法]在优化的马铃薯晚疫病CARAH预警系统指导下,采用随机区组设计对6种新型杀菌剂及2种植物源农药在马铃薯主栽品种合作88上进行大春马铃薯晚疫病田间药效评估,评价不同杀菌剂对马铃薯叶部和茎部的晚疫病防效。从预测中心病株开始,晚疫病每完成一代侵染进行一次防控。[结果]预警系统预测合作88将在7月2-4日出现中心病株,田间调查显示,对照处理7月3日出现马铃薯晚疫病中心病株,优化的预警系统预测中心病株出现时间的准确率达100%;根据预警系统指导,从7月1日第一次施药至8月30日最后一次施药共开展9次防控。对马铃薯叶部和茎部晚疫病调查显示:8种杀菌剂对马铃薯叶部和茎部晚疫病的防效分别在85.50%和87.50%以上,其中31%噁酮·氟噻唑的防效最高,分别达到95.00%和96.75%;植物源杀菌剂0.3%丁子香酚的防效较高,分别达到90.50%和92.50%。预警系统指导下应用8种杀菌剂对马铃薯增产显著,增产幅度在116.29%~257.69%,对照处理的商品薯率仅为38.27%,杀菌剂防控的商品薯率为71.60%~79.94%。[结论]CARAH系统测报与田间晚疫病的实际发生高度吻合,可精准指导晚疫病防控。6种化学杀菌剂和2种植物源农药对马铃薯晚疫病均有较高防效,推荐在生产中用于晚疫病防控,尤其是植物源农药丁子香酚替代化学杀菌剂的应用可以显著减少化学杀菌剂的使用量。

中国马铃薯晚疫病监测预警系统“China-blight”的组建及运行

马铃薯晚疫病是严重威胁世界马铃薯生产和粮食安全的重要病害之一,同时也是植物病害中流行速度最快的病害之一。由于品种多不抗病,目前国内外主要依靠化学防治控制该病害。为了提高用药的时效性,将信息技术与植物病害流行学原理相结合,设计并组建了中国马铃薯晚疫病监测预警系统"China-blight"(www.china-blight.net)。该系统由"中国晚疫病实时分布"、"未来48小时不同区域晚疫病菌侵染危险性预测"和"晚疫病化学防治决策支持系统"等子系统构成,此外还包括"晚疫病防治方法"、"品种抗病性"、"化学药剂库"、"其他病虫害"、"问题与经验交流"和"用户田间管理电子档案"等知识信息与服务功能。通过对2009年我国北方马铃薯一作区6-7月份病害侵染时段出现次数与晚疫病实际发生情况进行比较,预测信息与病害实际发生程度相符,该系统可以用于对马铃薯晚疫病田间防治的指导。

过表达三七PnSS基因调控马铃薯对交链格孢引起的早疫病抗性

[目的]研究马铃薯中过表达三七PnSS基因对早疫病抗性的影响。[方法]从三七叶中克隆PnSS基因,使用邻接法构建三七PnSS及其同源物的系统发育树,通过农杆菌介导法转化马铃薯“剑川红”,随机挑选2个转基因株系在自然条件下接种病原菌交链格孢(Alternaria alternata)并统计病情指数,利用PCR方法检测生长素基因StYUCCA8、StPIN1和StPIN2的表达水平。[结果]从三七中克隆PnSS基因,系统发育树显示三七PnSS基因与西洋参中的同源物处于同一聚类中,但与茄科植物的同源物处于不同的聚类。三七PnSS基因转化马铃薯后获得12个转基因株系,随机挑选2个株系并接种交链格孢,发现表达PnSS的转基因马铃薯植株对早疫病显示出抗性,进一步发现StYUCCA8和StPIN2的表达水平在转基因马铃薯接种交链格孢前后均降低,StPIN1的表达水平在转基因植株接种交链格孢前升高,而接种交链格孢后降低。[结论]PnSS基因的过表达降低了生长素基因StYUCCA8、StPIN1和StPIN2的表达而提高马铃薯对早疫病的抗性,为利用PnSS基因开展马铃薯育种并获得抗早疫病马铃薯品种建立理论基础。

马铃薯早疫病病原菌分离鉴定及不同植物提取物、茵陈二炔酮抑菌活性研究

[目的]明确曲靖市会泽县马铃薯早疫病的病原菌,并探究不同植物提取物和茵陈二炔酮对病原菌的抑菌活性,为马铃薯早疫病的生物防治提供科学依据。[方法]采用组织分离法分离纯化病原菌,通过形态学和分子生物学方法鉴定病原菌,利用菌丝生长速率法筛选对病原菌有抑制效果的植物提取物,同时测定茵陈二炔酮抑菌毒力以及对菌丝形态、干重、还原糖、总蛋白含量的影响。[结果]曲靖市会泽县马铃薯病叶分离纯化的病原菌经鉴定为交链格孢菌(Alternaria alternata)。12种植物提取物(1 mg/mL)中椴叶鼠尾草和紫茎泽兰提取物的抑菌效果最好,抑菌率分别为55.19%和40.76%。茵陈二炔酮抑菌效果随着浓度升高而增强,经毒力测定其EC_(50)在16.418~46.576μg/mL。茵陈二炔酮使菌丝形态发生细微变化,干重显著减轻,还原糖、总蛋白含量显著降低。[结论]曲靖市会泽县马铃薯早疫病病原菌为交链格孢菌,椴叶鼠尾草和紫茎泽兰提取物对交链格孢菌有良好的抑菌效果,茵陈二炔酮通过阻碍菌丝细胞物质合成与能量代谢,影响菌丝正常生长以达到较好的抑菌效果。

地质高背景区晚疫病马铃薯根际土壤细菌群落对重金属胁迫的响应

探究地质高背景区重金属胁迫下晚疫病马铃薯根际土壤细菌群落变化及其影响因素,对马铃薯安全生产具有重要意义。采集马铃薯(‘青薯9号’‘威芋5号’和‘威芋3号’)健康植株和晚疫病发病植株根际土壤,检测土壤p H、有机质和重金属含量,用Illumina MiSeq高通量测序技术分析细菌群落;采集马铃薯块茎,测定重金属含量。试验区土壤Cd、Cr和Zn含量均值分别为2.14、170和220 mg/kg,Cd含量超过国家土壤质量标准风险管制值,Cr和Zn含量超筛选值。马铃薯块茎仅1个样品Cd含量为0.103 mg/kg,超过国家食品安全限值标准。发病马铃薯根际土壤优势细菌门及其相对丰度主要为变形菌门(Proteobacteria)33.16%~39.09%、放线菌门(Actinobacteria)13.45%~17.11%;优势菌属主要为鞘脂单胞菌属(Sphingomonas)8.78%~12.30%、芽单胞菌属(Gemmatimonas)6.22%~7.61%,发病植株优势菌相对丰度与健康植株存在差异。不同品种间细菌多样性与丰度不同,马铃薯感染晚疫病后根际土壤细菌群落多样性升高,细菌菌群丰度下降。主成分分析显示发病植株与健康植株细菌群落差异性贡献率为29.59%。冗余分析结果表明,土壤重金属和pH显著影响土壤细菌群落组成和结构,对优势菌群的影响尤为明显,健康与发病植株间细菌群落的差异受土壤Pb、Cr胁迫的影响更大。因此,地质高背景区重金属胁迫下马铃薯可实现安全生产,染病马铃薯植株根际土壤细菌群落多样性降低,丰富度上升,土壤Pb、Cr通过改变根际土壤细菌群落有益菌类而影响晚疫病的发生和发展。

基于CARAH模型的重庆春马铃薯晚疫病侵染特征模拟分析

马铃薯晚疫病是影响马铃薯产量的首要病害,研究其在山地立体气候条件下的发生流行特征具有重要意义。本文利用重庆地区260个地面气象观测站2019年-2023年小时级温湿度数据,采用CARAH模型模拟分析了春马铃薯晚疫病侵染频度、严重程度、关键侵染周期等时空特征,并采用巫溪县2022年马铃薯田间小气候监测数据对模拟精度进行了检验。结果表明,采用小时级地面气象观测数据模拟的晚疫病侵染空报率、漏报率均在20%以内,整体精度较佳。5年气象数据模拟结果显示,重庆地区气候条件有利于春马铃薯晚疫病的发生发展,早、晚熟品种栽培期普遍发生4~8代(11~20次)、8~12代(21~40次)侵染;严重程度呈现“两极化”特点,轻度和极重度侵染次数具有明显优势。第3代第1次和第5代第1次2个关键侵染周期的开始期分别在3月上旬至4月下旬、3月下旬至5月中旬,高峰期分别为3月下旬和4月中旬。春马铃薯晚疫病侵染的空间分异特征明显,东北部主产区侵染代数、次数、极重度侵染次数均少于其他产区,是晚疫病发生最轻的地区。关键侵染周期的开始时间随海拔升高而推迟,中西部丘陵低山地区早,东部武陵山与大巴山区晚。

利用最大熵和CARAH模型评估重庆春马铃薯晚疫病气候风险

基于2019-2023年2-6月重庆市260个地面气象观测站逐小时平均气温、平均相对湿度数据,利用CARAH晚疫病模型模拟重庆春马铃薯晚疫病侵染风险的空间分布,通过气候网格数据构建最大熵模型,筛选马铃薯晚疫病气候影响因子,评估春马铃薯晚疫病气候风险,为春马铃薯晚疫病预测与科学防控提供参考依据。结果表明:基于CARAH模型采用小时级气象数据模拟晚疫病侵染的准确性较高,空发生率为12.5%,漏发生率为18.5%,TS评分为0.73。降水量是影响重庆春马铃薯晚疫病风险分布的主导因子,相对湿度和气温是重要因子,其幼苗期、现蕾开花期气候变量对晚疫病风险的影响较大。各马铃薯熟性(早/晚)与感病性(抗病/感病)组合的晚疫病低风险区面积少于或接近1万km^(2),平均面积占比为10.2%,中风险区和高风险区面积均超过3万km^(2),平均面积占比分别为43.7%和46.1%。重庆春马铃薯晚疫病气候风险呈中间高、周边低的空间分布特征,高风险区集中于重庆的川东平行岭谷地区,中风险区主要分布于渝东北大巴山区、渝东南武陵山区以及渝西川中丘陵一带,低风险区多呈片状分散在重庆边缘地带。重庆春马铃薯生产面临较高的晚疫病气候风险,空间分异特征显著,应通过合理生产布局和改进栽培技术加以应对。

不同药剂混配使用对榆林地区马铃薯早疫病的田间防效试验

采用田间喷雾施药,在陕西省榆林市进行了马铃薯早疫病防治技术研究。开展不同药剂混配的防效比较试验。试验结果表明:不同处理均对早疫病有抑制作用,且存在显著差异,其中:苯酰锰锌+精甲霜锰锌、吡唑醚菌酯+枯草芽孢杆菌、代森锰锌+氟噻唑吡乙酮药剂组合对早疫病防效较好,防效分别为74.2%、70.3%、67.6%,兼有防控晚疫病作用,建议推广使用;丙森锌+烯酰吗啉、苯酰锰锌+精甲霜锰锌、氟啶胺+氟菌·霜霉威、嘧菌酯+噁酮·霜脲氰处理的防效较差,依次为:58.9%、54.6%、50.8%和50.5%。

马铃薯StRac5、StRac7和StRac13基因的克隆及其表达模式分析

探究马铃薯基因的表达模式,为后续研究基因对马铃薯病害的抗性影响提供理论依据。以马铃薯为试验材料,克隆获得3个马铃薯内源小G蛋白基因StRac5、StRac7、StRac13,并对其进行生物信息学分析和表达模式分析。结果表明,StRac5、StRac7、StRac13与拟南芥和水稻中的小G蛋白含有相似的保守序列,均属于ROP蛋白。StRac5和StRac13的蛋白结构域与拟南芥AtRop1、AtRop3、AtRop5、AtRop6及水稻OsRac5、OsRac6、OsRac7相同,StRac7与拟南芥AtRop9的蛋白结构域相同。系统进化树分析表明,StRac7属于第Ⅱ类,与拟南芥AtRop9遗传距离最近;StRac13属于第Ⅲ类,与拟南芥AtRop7遗传距离最近;StRac5属于第Ⅳ类,与水稻OsRac5和OsRac6遗传距离最近。在马铃薯不同组织中,StRac5、StRac7、StRac13基因的相对表达量均为叶>根>茎;与其在茎中表达量比较,StRac5、StRac7和StRac13在叶中的表达量分别增加了1222.4%,2531.3%,468.2%;接种晚疫菌后,StRac5、StRac7和StRac13基因的相对表达量均出现先升高后降低的趋势,StRac5和StRac13基因的相对表达量在接菌24 h后较0 h分别上调了62.2%,40.4%,StRac7基因的相对表达量在接菌72 h后较0 h上调了827.8%;经过ABA、SA、GA和6-BA处理后,StRac5、StRac7、StRac13基因的相对表达量呈现下调的趋势;JA和IAA处理后,StRac5、StRac7、StRac13基因的相对表达量呈现上调的趋势。因此,StRac5、StRac7和StRac13基因能够响应马铃薯晚疫病的侵染,在不同组织和不同激素处理下表达模式也存在一定差异。

3种施药方案对马铃薯晚疫病的防治效果及经济效益分析

马铃薯晚疫病是马铃薯生产上的重要病害,目前化学药剂防治仍是防控该病害的重要手段。本研究共设计3种马铃薯晚疫病药剂防控方案:方案1为0.3%丁子香酚可溶液剂+10%烯酰吗啉水乳剂160 g/(667 m^(2)·次);方案2为0.3%丁子香酚SL+10%烯酰吗啉EW 120 g/(667m^(2)·次)+代森锰锌60 g/(667m^(2)·次)+增效酮梨15 g/(667m^(2)·次);方案3为代森锰锌60 g/(667m^(2)·次)+增效酮梨15 g/(667m^(2)·次)+68.75%氟菌·霜霉威悬浮剂60 mL/(667m^(2)·次)/10%氟噻唑吡乙酮可分散油悬浮剂15 mL/(667m^(2)·次)/50%氟啶胺悬浮剂30 mL/(667m^(2)·次)(其中68.75%氟菌·霜霉威悬浮剂、10%氟噻唑吡乙酮可分散油悬浮剂、50%氟啶胺悬浮剂依次交替使用),根据田间马铃薯晚疫病发病进展,并结合晚疫病预警系统信息进行田间施药,对其防治效果和防治成本进行比较评价。结果表明,在整个防控期内,3种药剂方案对马铃薯晚疫病均具有较好的防控效果,田间防效均在90%以上;3种药剂方案处理的增产效果显著,产量均极显著高于清水对照CK的产量,3种方案间防效和产量无显著性差异;方案1药剂投入成本最低,方案2投入产出比最小,其中方案1中含有0.3%丁子香酚植物源药剂,不仅节约了成本,且减少了化学农药的使用。在实际生产中几种方案可交替使用,避免长期单一使用某种农药而产生抗药性。