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1.
Development of potato cultivars resistant to Erwinia species (Erwinia carotovora subspeciesatroseptica, E. carotovora subspeciescarotovora, andErwinia chrysanthemi) causing soft rot of stems and tubers involves identification and transfer of the resistance to breeding lines possessing desirable agronomic traits. In total, 363 accessions of six wildSolanum species, three somatic hybrids and nine sexual progeny of somatic hybrids were screened for stem soft rot resistance. Thirty-one, 50, and 67 percent of accessions ofSolanum boliviense, Solanum chacoense, and Solanumsanctarosae, respectively, were resistant or highly resistant, whereas, 100, 97, and 95 percent of accessions ofSolanum canasense, Solanum tarijense, andSolanum spegazzinii were susceptible or highly susceptible, respectively. Two tuber soft-rot resistant somatic hybrids, A937 and T355-11 produced earlier by the fusion ofSolanum brevidens (PI 218228) andSolanum tuberosum (PI203900) orS. tuberosum cv. Russet Burbank, respectively, and the sexual progeny of A937 andS. tuberosum cv. Katahdin were also highly resistant. Transfer of resistance fromS. brevidens to somatic hybrid (A937) and subsequently to the progeny suggests that the resistance is simply inherited. In addition to the identification of 65 resistant or highly resistant clones of wildSolanum species, this study has identified three tuber soft rot-resistant clones that are also resistant to stem soft rot. Potato cultivars showed a range of responses to the pathogen.  相似文献   

2.
为发现抗白绢病的抗源材料,以花生28个种质为材料,在阳逻和武昌两地开展了白绢病抗性鉴定,并在温室条件下对其中11个材料进行抗性检测。结果表明:材料间白绢病发病率存在显著性差异(P<0.05);两试点鉴定获得5份中等抗病材料,其收获前死亡率低于30%。在温室接种条件下,2份材料鉴定为中等抗病。综合田间和温室试验结果,中花212和麻阳小子为中抗白绢病材料,为我国首次报道;中花212还兼抗细菌性青枯病。  相似文献   

3.
为明确山东省主栽花生品种对疮痂病的抗性及疮痂病对花生产量的影响,2018-2019年在山东省莱西市对36个主栽品种进行了抗疮痂病鉴定,鉴定通过人工接种分别在田间和温室大棚内进行,并分析了病害对产量影响。结果表明,供试品种有高感品种8份,占鉴定品种总数的22.22%;感病品种4份,占鉴定品种总数的11.11%;中抗品种2份,占鉴定品种总数的5.56%;抗病品种11份,占鉴定品种总数的30.56%;高抗品种11份,占鉴定品种总数的30.56%。花生疮痂病病情与产量损失率呈指数关系,病情指数越高,花生产量损失率越大。  相似文献   

4.
The aim of this work was to identify Vicia faba germplasm resistant both to rust and chocolate spot. A collection of 43 accessions of V. faba previously identified as chocolate-spot resistant was evaluated for rust and chocolate spot resistance in Egypt and in Spain. The genotype and genotype × environment (GGE) biplot analyses allowed the selection of 11 accessions resistant to both diseases in those locations. These 11 accessions were evaluated for rust in an additional field trial in Spain, all performing better than the susceptible check. The joint analysis of the 11 accessions in the four field trials where they had been evaluated revealed no significant effects either for genotype, environment or the genotype × environment interaction. They are hence promising sources of resistance, both for their low severities and their stable responses across the studied environments. This collection was also tested under controlled conditions against the Egyptian and the Spanish isolates of rust present in the field trials further underlining the stable performance of these genotypes. Finally, the effect of previous infection with chocolate spot on rust resistance was assessed under controlled conditions and no influence of it was found.  相似文献   

5.
《Field Crops Research》2005,91(2-3):125-130
Stem rot, a fungal disease caused by Sclerotinia trifoliorum Eriks., is often a serious problem in many important forage legumes including faba beans (Vicia faba L.). Understanding the inheritance of resistance to the disease is essential for effective breeding of resistant cultivars. Experiments were conducted to study the inheritance of resistance to stem rot of faba beans. The F1, F2, and the backcross generations of five crosses between four resistant and four susceptible populations (Alto × Polycarpe, A-90 × Polycarpe, ILB-1814 × A-247, A-90 × A-244, VT × Tanagra) were used. The eight populations were crossed properly in the field, and progenies of F1 and F2, as well as backcross progenies of F1 with each of their parents, were evaluated for resistance to stem rot disease under controlled conditions after artificial inoculation of the plants with carrot root pieces colonized by the fungus. On the assumption that inheritance of stem rot resistance is governed by a single dominant gene, no significant differences were found between the observed and the expected frequencies of resistance for progenies, except for one cross. As the expression of resistance to the disease fits the expected ratios for a single dominant gene model, it is concluded that the inheritance of resistance to sclerotinia stem rot in the evaluated faba bean populations is controlled by a single dominant gene.  相似文献   

6.
In recent years, peanut yield and quality are more seriously affected by pod rot disease in China. However, managing this disease has proven challenging due to the wide host range of its pathogens. In this study, four soil samples were collected from fields with pod rot disease in Hebei Province, and 454 pyrosequencing was used to analyze the fungal communities structure within them. All 38 490 ITS high-quality sequences were grouped into 1203 operational taxonomic units, the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index. The results showed that members of Ascomycota were dominant, followed by Basidiomycota. According to the BLAST results at the species level, Guehomyces had the highest abundance, accounting for about 7.27%, followed by Alternaria, Fusarium, and Davidiella. The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control, indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area. This study delved into the broader fungal community associated with peanut pod rot, providing a theoretical foundation for preventing and treating this disease in agriculture.  相似文献   

7.
为筛选花生黑斑病抗源材料,以50个花生品种为材料,在山东省莱西市田间开展黑斑病抗性调查,并在温室条件下对其中7份材料进一步开展抗性鉴定。结果表明,不同花生品种在田间对黑斑病抗性存在差异,共获得4份中等抗病材料;在温室接种条件下,3份材料鉴定为中等抗病。综合田间自然发病和温室人工接种鉴定结果,获得冀农G94、豫花47号和晋花10号3份中抗黑斑病的材料。  相似文献   

8.
采用自然病圃鉴定法,对76个花生品种(系)进行了花生果腐病抗性评价,以期为抗病育种及田间病害防 治提供理论依据和抗性材料。结果表明,不同花生品种间对花生果腐病的抗性存在着显著差异,供试76份花生品 种(系)中未发现对果腐病免疫的品种,获得高抗品种2个,抗病品种7个,中抗品种12个,感病品种21个,高感品种 33个。聚类分析结果表明,分支I中的9个品种(尤其是花育9115)抗性较好,可进一步加以利用。花生对果腐病的 抗感性与荚果鲜重之间不存在显著相关。  相似文献   

9.
From 1993 to 1996 three groups of potato genotypes were evaluated for resistance toErwinia spp.: (1) 31 interspecific diploid hybrids (28 resistant and three susceptible), (2) five hexaploid or pentaploid somatic hybrids ofSolanum tuberosum (tbr) ×S. brevidens (brd), and (3) eight cultivars. Two evaluation methods were applied: tuber point inoculation with eitherErwinia carotovora ssp.atroseptica (Eca) orE. chrysanthemi (Ech) to test tuber soft rot resistance and stem base inoculation with Eca to test blackleg resistance. Some resistant diploid hybrids and somatic hybrids oftbr × brd were superior to cultivars for both tuber and stem resistance. Tuber and stem resistance toErwinia spp. in the most resistant diploid hybrids were equal to the highly resistant somatic hybrids oftbr xbrd. Tuber resistance to Eca was highly correlated to tuber resistance to Ech (r=0.815***). In two years of evaluation for stem resistance, three diploid hybrids and a derivative of one of the somatic hybrids (USA M 264) failed to develop symptoms of blackleg following inoculation with Eca, Analyses of variance for tuber and stem resistance indicated significant effects of genotype, year and genotype × year interaction. A positive relationship between tuber and stem resistance toErwinia spp. has been found, however the genetic control of resistance in tuber and stem is partially independent. In the case of Eca the correlation coefficient was r = 0.725***. Therefore it should be possible to obtain resistant genotypes to both blackleg and tuber soft rot. Several resistant diploid hybrids were selected from among those tested, which also have several other characters desirable for potato breeders.  相似文献   

10.
Bacterial soft rot is a serious disease in potato (Solanum tuberosum L.), causing rapid tuber tissue maceration and, consequently, marketable yield loss. Soft rot bacteria, including Pectobacterium carotovorum subsp. carotovorum (Pbc), are favored by moist conditions, which are prevalent in large potato storage facilities. However, although most potatoes in North America are stored before use, there are no published surveys of soft rot resistance in cultivars exposed to long-term storage conditions. Thus, we tested 65 cultivars and 13 breeding lines for soft rot resistance after 6 months of storage. There was a significant effect of cultivar and production environment on soft rot resistance score. During 6 months of storage, tuber soft rot resistance in resistant clones did not change, while it changed in susceptible clones. The three most resistant cultivars to soft rot were Freedom Russet, Anett, and Alaska Red Eye.  相似文献   

11.
为给河南省抗茎基腐病品种合理布局提供品种支撑,以河南省小麦茎基腐病的高致病力假禾谷镰孢菌菌株PY20-20为接种物,对参加河南省主要区域试验的308个小麦新品系进行苗期抗病鉴定。结果发现,供试品系中,95.7%的品系表现为高感(病情指数大于30.00),仅1.95%的品系表现为中抗(病情指数在10.01~20.00之间),3.25%的品系表现为中感(病情指数在20.01~30.00之间),无免疫和高抗品种,表明参加河南省小麦区域试验的新品系对小麦茎基腐病的整体抗性水平较低。为获得茎基腐病抗性稳定的品系,对苗期表现为中抗和中感的品系进行了2次重复验证,发现6个中抗品系(西农1125、郑麦9134、中研麦906、阜麦1008、泰禾麦6号和民研186)和4个中感品系(徐麦14017、周麦36、新麦9389和囤麦257)的抗性水平较为稳定。进一步对6个中抗品系进行成株期抗性鉴定,发现这些品系的病情指数在12.67~15.50之间,成株期对小麦茎基腐病的抗性也达到了中抗水平。综上,西农1125、郑麦9134、中研麦906、阜麦1008、泰禾麦6号和民研186这6个中抗茎基腐病的品系可以在小麦生产...  相似文献   

12.
花生白绢病是世界花生上发生的一种重要土传真菌性病害,近十年来在我国山东、河南、广东、辽宁、江西等主要花生产区发生为害逐年加重,已成为制约花生产量和质量的重要因素。本文对花生白绢病的发生为害、病原菌的生物学特性与变异、病害流行和防治等方面进行综述,并对今后花生白绢病研究提出一些建议,以期为我国花生白绢病工作者提供参考。  相似文献   

13.
为选育抗线虫花生品种,在北方花生根结线虫分布较均匀的自然病田中种植了102份花生种质,收获时对其进行抗性鉴定调查,得到高感材料14份、中感材料76份、中抗材料12份、耐病材料1份,未发现免疫和高抗种质材料;调查发现种间杂种的杂交后代抗性较强,中抗材料较多;自然病田田间观察发现,紫色种皮花生种质的抗性表现较好。  相似文献   

14.
Crown rot caused by Phytophthora capsici is becoming an increasingly important disease of vegetable crops in southeastern U.S. In recent years, the practice of grafting watermelon onto rootstocks belonging to other Cucurbitaceae genera has also been slowly gaining adoption in the U.S. However, it is not known how these rootstocks, developed mainly in Asia, will respond to diseases prevalent in local production areas. We evaluated the available commercial watermelon rootstocks for resistance to Phytophthora crown rot by inoculating them with a zoospore suspension of P. capsici in four different trials. Disease development on rootstocks was rated on a 1–9 scale (1 = no symptoms, 9 = plant dead). Based on all the four trials, the commercial Lagenaria siceraria (bottle gourd) rootstocks, FR-Strong, Emphasis, Macis and WMXP-3938 were resistant (Mean rating ≤3) to crown rot when compared to susceptible watermelon checks (mean rating >8). All Cucurbita inter-specific hybrid rootstocks and a watermelon rootstock Ojakkyo, were highly susceptible to crown rot (mean rating >8). Real-time quantitative polymerase chain reaction (qPCR) using two different P. capsici specific primers (ITS and β-tubulin) indicated the presence of significantly (P < 0.0001) greater amounts of P. capsici DNA g−1 plant tissue in susceptible Cucurbita inter-specific hybrid rootstocks (β-tubulin, mean = 2895 ng) and watermelon (2665 ng) compared to the L. siceraria rootstocks (357 ng). Crown rot resistant bottle gourd rootstocks may be useful in areas where P. capsici is a recurring problem. The present study identified several commercial bottle gourd rootstocks with resistance to Phytophthora crown rot, and confirmed their levels of resistance using qPCR.  相似文献   

15.
The aim of this work was to find new sources of resistance to chocolate spot disease, and to validate their stability across different environments. In order to do so, a collection of 307 accessions of Vicia faba was screened for resistance to Botrytis fabae under field conditions; stability of resistance of the 40 most-resistant accessions was tested in a multi-location experiment in Austria, Chile, Egypt, France and Spain over two field seasons. Although complete resistance was not found, nine accessions showed interesting levels of incomplete resistance (ranging from 10 to 20% of average severity across environments, maximum average severity being 47.9%). Genotype × environment interaction accounted for 22% of the sum of squares of the multi-environment evaluation, revealing instability of the phenotypic expression across environments. This usually hampers the efficiency of selection and reduces the adaptability of the plant material. Three accessions stand out for their consistent resistance, both in terms of reduced disease severity and high stability, which make them good candidates for breeding programs. As for environments, those with the highest total severity mean were the most discriminant between accessions. In contrast, those with lower severity means were the most representative of the whole range of environments. It can be concluded that validation of resistance to chocolate spot in different environments is an essential step when screening for material of interest and should be taken into account for further works.  相似文献   

16.
花生茎点霉(Phoma arachidicola Marasas Pauer & Boerema)引起的花生网斑病在生产上普遍流行、危害严重,2018-2019年通过2年的田间接种试验对国内65份花生种质资源网斑病抗性进行测评。以采自山东莱西的病原菌菌株Wb2制备105/mL的孢子悬浮液喷洒于花生叶片表面进行接种,对照区喷施50%咯菌腈WP防治花生网斑病菌。结果表明,65份种质中,抗病(resistant,R)资源8份,占鉴定资源总数的12.3%;中度抗病(moderately resistant,MR)资源9份,占比13.8%;感病(susceptible,S)资源37份,占比56.9%;高度感病(high susceptible,HS)资源11份,占比16.9%。测定抗病性不同资源产量损失差异,结果表明,花生网斑病菌对花生产量影响显著,产量损失率随抗病性的降低而升高。本研究为花生抗网斑病育种提供抗源材料,并为病害产量损失评估提供理论依据。  相似文献   

17.
In North Carolina (NC), USA, Pythium stem rot on tobacco is caused by Pythium aphanidermatum. During the past 10 years, Pythium stem rot incidence has been reported more frequently in tobacco fields than before. Since 1997, tobacco flue-cured cultivars carrying the Ph gene that confers immunity to race 0 of Phytophthora parasitica var. nicotianae (Ppn) have also been deployed in NC. It has been questioned whether the introduction of cultivars carrying this resistance gene contributes to the increased incidence of Pythium stem rot. We used a strain of P. aphanidermatum expressing the β-glucuronidase (GUS) reporter gene to investigate the susceptibility of stem and root tissues of four flue-cured tobacco cultivars to Pythium stem rot. Cultivars NC71 (carries the Ph gene) and RJR15 (no Ph gene, but highly resistant to Ppn) were less susceptible (P < 0.05) to P. aphanidermatum than K326 and K346 cultivars that do not carry the Ph gene. Furthermore, different parts of the plant demonstrated significant differences (P < 0.0001) to P. aphanidermatum infection although the significance depended on the cultivar. That is, in K326 and NC71 the highest percent infection was in the adventitious roots, followed by the stems and lastly the true roots, whereas in K346 and RJR15 the highest percent infection was in the adventitious roots, then the true roots and last in the stems. These results do not support the hypothesis that cultivars carrying the Ph gene may be more susceptible to Pythium stem rot than cultivars without the gene. It is likely that other reasons such as the reduction or absence of mefenoxam application in fields where cultivars carrying the Ph gene are planted or reduction in competition for infection cites with Ppn have contributed to the increase of Pythium stem rot incidence in tobacco fields in NC.  相似文献   

18.
Peanut fields are monitored for pod rot, which is typically caused by Pythium spp. and Rhizoctonia solani, in order to determine need, and the type and timing of fungicide applications. Pod rot can lead to damaged peanut kernels and when damage exceeds 2.49%, substantial price reductions occur. Nine fields or tests were sampled weekly for pod rot during the 2009 through 2012 growing seasons. The sampling was conducted on fields treated uniformly with fungicides for pod rot or within large research plots with various fungicide treatments. Pythium myriotylum was the most frequently identified pathogen species, although Rhizoctonia spp. were also recovered from diseased pods at all sites. Pod rot incidence was related to percent damaged kernels at harvest in 3 of 5 sites. Collection of 304 samples (sample unit = 46 cm of row) in a field was required to estimate 1% pod rot accurately (CV = 20%). There was a linear relationship between average % pod rot in a field, and the percentage of sampling units (absence/presence) with pod rot at low disease incidences. Scouting for pod rot of peanuts to make in-season fungicide applications will be hampered by high sample number, destructive sampling of plants, frequent sampling (due to rapid increase of disease), and the poor relationship between disease during the season and kernel damage at harvest. Making one preventative application at 60–70 days after planting may be a better practice than timing the initial fungicide application based on sampling for disease.  相似文献   

19.
Mechanically harvested tubers of 14 potato cultivars grown on both loamy sand and silt loam soils were evaluated for resistance to bacterial soft rot caused byErwinia carotovora subsp.atroseptica. Cultivars were also assayed for calcium and dry matter content to determine possible correlations with soft rot resistance. Resistance of potato tubers to bacterial soft rot was assayed after harvest by inoculating tubers and determining percent surface area decayed after four days in a mist chamber. Tubers of the cultivars differed widely in resistance to bacterial soft rot. The ranking of the resistance of tubers from different cultivars to bacterial soft rot was similar for both soils, although disease severity in tubers from a particular soil type varied with the season. Of the cultivars tested, tubers of Butte, Russet Burbank, and Nor-gold Russet were ranked as the most resistant, whereas tubers of Redsen, Norchip, Norland and Belchip were rated as the most susceptible. Tubers of Rhinered, Red La Soda, Superior, Pontiac, Atlantic, and Nooksack were intermediate in resistance. Neither calcium concentration in medullar tissues nor dry matter of potato tubers alone could be correlated with ranking of the cultivars with respect to severity of bacterial soft rot. However, a multiple linear regression model incorporating both variables indicated that tubers with a high content of both calcium and dry matter were likely to be less susceptible to bacterial soft rot than were tubers with lower percentages of these variables.  相似文献   

20.
Greenhouse assays were carried out to characterizeSolanum accessions previously reported to be late blight resistant and to identify individuals within the accessions with high levels of resistance to late blight. Foliage of wildSolanum species accessions or hybrid cultivated potato x wild species (diploid or tetraploid) from Mexico, Russia, or South America was inoculated withPhytophthora infestans (US-8) and was scored for severity of foliar symptoms at 7 and 14 days after inoculation (DAI). Mexican accessions (S. brachycarpum,S. pinnatisectum,S. guerreroense, andS.fendleri) were significantly more resistant (1.1% infection at 14 DAI) than either Russian (59.1% infection at 14 DAI) or South American (53.4% infection at 14 DAI) accessions. Moreover, the genotypes within the Mexican accessions tended to be more uniformly resistant whereas genotypes within the Russian and South American accessions tended to segregate for resistance. The more resistant genotypes of Russian and South American accessions (176/546) were retested, and 56 genotypes were identified as having potential for use in potato breeding programs for resistance to late blight. Fifty percent of the selected genotypes were fromS. microdontum accessions PI498124, PI595510, and PI595511. The potential of these species for incorporation into breeding programs for late blight resistance is discussed.  相似文献   

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