首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 562 毫秒
1.
The susceptibility of leaves and berries of five night-shade species to infection by the potato late blight pathogenPhytophthora infestans was tested. American black nightshade (Solanum americanum) and eastern black nightshade (Solanum ptycanthum) were resistant to infection. However, two accessions (entire-edged and dentate-edged leaf) of hairy nightshade (Solanum sarrachoides), cutleaf nightshade (Solanum triflorum), and bitter or climbing nightshade (Solanum dulcamara) were susceptible. Survival of the pathogen in susceptible species was tested under different environmental conditions. The pathogen survived for at least 2 wk in both hairy nightshade accessions when plant material was kept in soil at a temperature of 20 C. However,P. infestans survived 48 h at ?15 C only in the entire-leaf hairy nightshade accession. In the laboratory, oospores of the pathogen were formed in inoculated plants of the two hairy nightshade accessions, cutleaf nightshade, and ‘Russet Burbank’ potato, but not in American black nightshade, bitter nightshade, or eastern black nightshade.  相似文献   

2.
Organophosphate and carbamate insecticides exert their neurotoxic effects by inhibiting acetylcholinesterase (AChE), thereby, prolonging the action of acetylcholine at cholinergic synapses, resulting in neuronal hyperexcitation. Mutations at the AChE target site confer modified acetylcholinesterase (MACE) phenotypes. Target-site insensitivity of AChE was characterized in field-collected, tobacco-adapted forms of the green peach aphid, Myzus persicae (Sulzer), from nine different states in the eastern United States from 2004 to 2007. The specific activity of the AChE among the 65 aphid colonies screened by Ellman's assay ranged from 0.017–0.259 U/min/mg protein. Eight colonies, with a wide range of specific activities were chosen to study the inhibition of AChE in the presence of two carbamate insecticides, methomyl and pirimicarb. IC50 values for methomyl ranged from 0.35 to 2.4 μM, while six out of eight colonies had lower values that ranged from 0.16 to 0.30 μM for pirimicarb. Two colonies that were inhibited by methomyl had very high IC50 values for pirimicarb, 40.4 and 98.6 μM respectively. The target-site insensitivity in these two colonies that are resistant to pirimicarb could be due to an ace2 gene mutation. This is the first instance where MACE phenotypes in M. persicae from the United States were studied and confirmed. The results indicate that the possible insensitivity due to MACE resistance in some colonies may render selected carbamate insecticides ineffective. Concerns of MACE resistance in managing the tobacco-adapted form of the green peach aphid on tobacco in the United States are discussed.  相似文献   

3.
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   

4.
Aleurotrachelus socialis is one of the most important pests of cassava (Manihot esculenta Crantz) in the Neotropics. In Colombia, high whitefly populations can reduce crop yields by 79%; and although the farmers intensify the use of insecticides, this practice is highly contaminating, costly and leads to the development of resistance in the insect. An alternative for managing whitefly populations is to develop genetically resistant varieties. Wild parents of Manihot are a useful source of genes against pests for the cultivated species of cassava. Based on prior research that showed the existence of moderate-to-high levels of resistance to A. socialis in Manihot flabellifolia, a wild species of cassava, this study was proposed to characterize this new source of resistance, evaluating the biology and demographics of A. socialis on eight accessions of M. flabellifolia, a susceptible check (CMC-40) and a resistant (MEcu72) check. The averages of A. socialis longevity and fecundity on the accessions were not significantly different to MEcu72, but different from CMC-40 (P < 0.05). Development time was not significantly different, ranging from 35–40 days on accessions and MEcu72 and 33.5 days on CMC-40 (P < 0.05). In contrast, the population growth rate (rm) was significantly lower on the M. flabellifolia accessions, with Fla 61 standing out with a growth rate 98 and 99% less than that obtained on MEcu72 and CMC-40, respectively. Once the resistant levels have been identified to A. socialis on the M. flabellifolia accessions, interspecific crosses of M. esculenta subsp. M. flabellifolia and backcross programs could be developed to incorporate the desirable characteristics from the wild relatives into elite progenitors of M. esculenta.  相似文献   

5.
This study investigated the transmission efficiency of Potato leafroll virus (PLRV) by four potato colonizing aphid species, Myzus persicae, Macrosiphum euphorbiae, Aphis gossypii and Aphis fabae, reported from leaves and yellow water trap. Physalis floridana was used as a test plant for virus transmission. DAS-ELISA was used for virus screening of samples as well as virus detection on the test plant after transmission experiment. A 2-h period was sufficient for the tested aphids to acquire PLRV virions. However, a difference in the transmission potential occurred according to the aphid species. The highest potential was recorded for M. persicae and M. euphorbiae, at 90 and 80%, respectively. For the first time, the study revealed the PLRV transmission efficiency of A. fabae, estimated at 50%. The lowest potential rate of 30% was recorded for A. gossypii. This study highlights the PLRV transmission capacities of four potato colonizing aphids suspected to play a key role in the spread of PLRV in potato seed production sites.  相似文献   

6.
The electronic traces resulting from the interaction of aphid salivation and plant fluid ingestion from acceptable and non-acceptable food sources are shown for the four potato-infesting aphid species,Myzus persicae (Sulzer),Macrosiphum euphorbiae (Thomas),Aphis nasturtii Kaltenbach, andAulacorthum solani (Kaltenbach). The behaviour of the four species on the aphid susceptible potato variety Katahdin, is described as a standard and the range of salivation intervals is used to describe the initial feeding behaviour of the aphid on its food source. The different periods spent in salivation prior to ingestion are further described and used to develop five categories of host acceptability, ranging from very acceptable (V), to unacceptable (I), based on the frequency of interruptions (aborts). This provides a means of screening potato materials for their resistance to aphid exploitation. It is shown that host discrimination occurs very early in the feeding approach.  相似文献   

7.
Multiple Allium accessions (garlic, and wild and ornamental Allium species) were screened for resistance using Penicillium allii and A. sativum (positive control). Single accessions of A. aflatunense, A. atroviolaceum, A. stipitatum, and Allium sp. remained asymptomatic. Single accessions of A. roseum and A. senescens, two accessions each of A. acuminatum and A. ampeloprasum and a single accession of A. moly displayed lesion expansion rates not exceeding 22%, 26%, 46%, 50%, 61%, 67% and 67%, respectively, of positive controls. Single accessions of A. sativum var. ophioscordon and A. scorodoprasum displayed rates not exceeding 68% and 55%, respectively, of positive controls with deep wounding, but did not consistently differ with shallow wounding. Accessions of A. canadense, A. sativum or A. longicuspis did not differ, differed inconsistently, or differed insubstantially from positive controls. Lesion expansion rates for A. acuminatum, A. ponticum and A. scorodoprasum were significantly less than in positive controls, but their small bulbs often rotted completely. Results document publicly available germplasm possessing significant resistance to P. allii.  相似文献   

8.
Several broomrape species including Orobanche crenata, Orobanche foetida and Phelipanche aegyptiaca are reported to infect various grain and forage legumes in the Mediterranean and West Asia. Pea (Pisum sativum) is severely damaged by O. crenata, but there are no reports on O. foetida or P. aegyptiaca infection. We report here that pea can induce high germination of seeds of O. crenata, O. foetida and P. aegyptiaca but only O. crenata success infecting pea roots and developing further. Some differences in levels of infection by O. crenata were observed among pea accessions what can be exploited in pea resistance breeding programmes. On the contrary, all pea accessions studied were highly resistant to infection by both O. foetida and P. aegyptiaca, preventing any tubercle attachment and development. This makes pea a promising candidate as trap crop for O. foetida and P. aegyptiaca seed bank demise in infested soils.  相似文献   

9.
Reciprocal grafts were done between potato (Solanum tuberosum) and six wildSolanum species known to be resistant to the Colorado potato beetle (Leptinotarsa decemlineata (Say)). Potato or wildSolanum foliage from each reciprocal graft was fed to first instar beetles or adult potato aphids (Macrosiphum euphorbiae (Thomas)). The proportion of second instar larvae after 48 h and survival and fecundity (number of nymphs per female) of the aphids were used to i estimate the resistance level of the foliage. Survival and fecundity of potato aphid were reduced on wildSolanum foliage (except withS. circaeifolium ssp.capsicibaccatum andS. okadae) used as scion or rootstock, but were not different from the control (potato-potato graft) on potato foliage. Development of Colorado potato beetle onSolanum foliage was reduced. In some cases, potato foliage grafted to wildSolanum became resistant to the beetle. Results suggest that a chemical factor or factors providing resistance to Colorado potato beetle are translocated from foliage of some wildSolanum species to potato foliage. They also indicate that mode of resistance to the two insects differs quantitatively or qualitatively.  相似文献   

10.
Increasing prevalence of potato leafroll virus (PLRV) and potato virus Y (PVY) has been reported in seed and commercial potato production, resulting in the rejection of potatoes for certification and processing. Host plant resistance to PLRV and PVY and their primary vector, green peach aphid,Myzus persicae, could limit the spread of these viruses. Host plant resistance to PLRV, PVY, and green peach aphid has been identified in non-tuber-bearingSolanum etuberosum (PI 245939) and in its backcross 2 (BC2) progeny. Resistance to green peach aphid involved a reduction in fecundity and adult aphid size. In addition, one BC2 individual was identified as possessing a genetic factor that was detrimental to nymph survival. PVY resistance was identified in all five BC2 progenies evaluated in a field screening under intense virus pressure. PLRV resistance was identified in two of the five BC2 progeny. This resistance was stable in field and cage evaluations with large populations of viruliferous aphids. Based on the segregation of virus resistances in the BC2 , PVY and PLRV resistances appear to result from the action of independent genetic mechanisms that reduce the levels of primary and secondary virus infection. Two BC2 individuals, Etb 6-21-3 and Etb 6-21-5 were identified as having multiple resistances to PLRV, PVY, and green peach aphid derived fromS. etuberosum. This germplasm could prove useful to potato breeders in the development of virus-resistant cultivars.  相似文献   

11.
Wild potatoes are important sources of genes for resistance to disease and insect pests. A collection of wild Mexican and South AmericanSolarium species from the US potato Genebank was evaluated under laboratory and/or field conditions for their reaction to late blight (Phytophthora infestans), Colorado potato beetle (CPB,Leptinotarsa decemlineata Say), and blackleg (Erwinia carotovora subsp.atroseptica (van Hall) Dye) in order to identify individual genotypes with multiple resistance genes. Late blight inoculations using aggressive isolates (US-8/A2 and US-11/A1 mating types) of P.infestans revealed a wide range of variation for resistance between and within the accessions of the wild species tested. For late blight, susceptible as well as moderately to highly resistant genotypes were observed in all the species tested. However, at least one accession from the three Mexican and one South American wild diploid species tested showed a relatively uniform high level of resistance toP. infestans. These includedS. bulbocastanum, S. pinnatisectum, S. cardiophyllum, andS. circaeifolium. Two accessions from South American speciesS. commersonii were highly susceptible to late blight. For the Colorado potato beetle test, only one species,S. pinnatisectum appeared uniformly resistant to CPB under field conditions. Results of screening for blackleg resistance showed that there were major differences between genotypes in the wild species. Accessions ofS. circaeifolium PI 498119 andS. bulbocastanum PI 243504 were identified as having significantly higher blackleg resistance than cultivated potato and the other wild species tested. However, genotypes from these two accessions were more susceptible to late blight and CPB. Characterization of theP. infestans isolate P1801C.16 used for late blight evaluation and multi-locus isolate tests using US-8/A2 and US-11/A1 races revealed that the resistance inS. pinnatisectum genotypes tested corresponded to a race-non-specific genetic system, which was different from any existing R genes.Solanum pin-natisectum genotypes with both high levels of late blight and CPB resistance as well as blackleg resistance genotypes identified in the present study represent a diverse gene pool that may be useful for development of new potato cultivars with multiple disease and insect resistance. The potential utilization of these valuable sources for improvement of cultivated potato is discussed.  相似文献   

12.
Sorghum accessions from Uganda were evaluated for grain mold and anthracnose resistance during the 2005 and 2006 growing seasons at the Texas A&M University Research Farm, near College Station, TX. Accession PI534117 and SC719-11E exhibited the lowest grain mold severities of 2.4, whereas, accessions PI534117, PI534144, PI576337, PI297199, PI533833, and PI297210, with SC748-5 were highly resistant to anthracnose in both years. Accessions PI534117, PI297134, PI297156 exhibited low grain mold severities in 2006. Significant negative correlation was recorded between grain mold and percent germination and high temperature in both years. In 2006, daily precipitation recorded significant positive correlation with grain mold. The seed mycoflora was analyzed across sorghum lines and treatments. In 2005, Curvularia lunata and Fusarium thapsinum were the most frequently recovered fungal species with 31 and 21% incidence, respectively, followed by Alternaria spp. (19%) and F. semitectum (13%). In 2006, predominant colonizers were F. thapsinum (58%), followed by Alternaria and F. semitectum with 15 and 10, percent respectively, while C. lunata had a 6% incidence. In this study, PI534117 holds promise for multiple disease resistance, as it had the lowest disease severity of grain mold and was highly resistant to anthracnose in both years. It also has a high germination rate, a high seed weight, and its short stature is more advantageous for the new A-line conversion program.  相似文献   

13.
Fifteen accessions ofSolarium berthaultii Hawkes andS. berthaultii xS. tarijense Hawkes were assessed for resistance to field infestations of the green peach aphid,Myzus persicae (Sulzer), potato leafhopper,Empoasca fabae (Harris), and potato fleabeetle,Epitrix cucumeris (Harris). Accessions bearing both Type A and Type B glandular trichomes were much more resistant to the green peach aphid and potato leafhopper than accessions bearing Type A hairs alone. All accessions had significantly smaller populations of these 3 pests than S.tuberosum cultivars. Total glycoalkaloid (TGA) content of foliage and tubers was not correlated with insect populations. Foliar TGA levels of field-grown plants varied among accessions, ranging from < 2–240 mg/100 g fresh wt. Solasonine and solamargine were the major foliar glycoalkaloids while solamarines predominated in tubers.  相似文献   

14.
This study aimed to determine the resistance/susceptibility to fire blight of apple germplasm resources from the province of Erzincan in eastern Turkey. In total, 32 native apple accessions from four regions within the province were tested under greenhouse conditions by inoculating the shoot tips with pathogenic bacterium. Shoot tips were wounded for inoculation. Genotypical susceptibility index (GSI%) values were computed for each genotype based on the length of the lesion that developed on each shoot. Accessions were grouped into five classes of resistance/susceptibility, as follows: Class A (resistant); Class B (moderately resistant); Class C (moderately susceptible); Class D (susceptible); and Class E (highly susceptible). GSI% values differed significantly among accessions (p < 0.01). Five accessions received a rating of Class A, and 7 accessions received a rating of Class B. This was followed by 9 accessions with a rating of Class C, 5 accessions with a rating of Class D and 6 accessions with a rating of Class E. The findings of this study are expected to contribute to breeding efforts with respect to apple resistance to fire blight.  相似文献   

15.
Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.  相似文献   

16.
Potato viruses in China   总被引：5，自引：0，他引：5  
Potato (Solanum tuberosum L.) is globally the fourth largest staple crop after rice, wheat and maize. China is the largest potato producer worldwide, accounting for 26.3% and 22.2% of the global total area and yield, respectively. Viral diseases have been a limiting factor for sustainable production of potato in China. This article provides update and comprehensive information on the most important viruses, their effect on yield and their control in China. Meristem culture is currently the most widely used technique for production of virus-free potato plants and these plants are used as nuclear stock for the production of certified seed tubers. Although a significant increase in tuber yield has been achieved using certified seed potatoes, lack of application of a national seed potato production scheme has hindered progress. Conventional breeding using virus-resistant cultivars introduced from other countries as parents has already led to the production of Chinese cultivars. Use of virus-resistant wild Solanum species and genetic transformation techniques will provide new virus-resistant varieties in the future to further enhance control of potato viruses in China.  相似文献   

17.
The susceptibility of three sweet potato cultivars (Ipomoea batatas L.) C4, TIS 3290 and TIS 9162 was evaluated against 156 isolates of Meloidogyne spp. with the aim to include resistant/tolerant sweet potato cultivars in a crop rotation scheme for the management of root-knot nematodes. The nematode isolates corresponded to races 1, 2 and 3 of Meloidogyne arenaria (n = 7), races 1, 2, 3 and 4 of M. incognita (n = 131) and Meloidogyne javanica (n = 18). Also, the isolates of M. incognita were differentiated in virulence groups: Pepper (n = 35), Pepper-Mi (n = 25), Tomato (n = 41) and Tomato-Mi (n = 30), depending on their ability to parasitize resistant pepper and tomato cultivars. The tested isolates of M. javanica parasitized C4 and TIS 3290, but not TIS 9162, whereas M. arenaria parasitized C4 and TIS 9162, but not TIS 3290, and M. incognita was able to parasitize the three sweet potato cultivars tested. C4 was the most susceptible cultivar to all nematode species tested, especially M. incognita, TIS 3290 was the most resistant and TIS 9162 was in between (7.2, 62.9 and 26.9% of resistant plants, respectively). Susceptibility of the sweet potato cultivars showed slight variations depending on the race or virulence group of M. incognita. The results suggest that sweet potato cultivars TIS 3290 and TIS 9162 may be used as rotation crops in fields where root-knot nematodes are present, their selection depending on the Meloidogyne isolates present. The use of resistant sweet potato cultivars would be preferably combined with other management practices to avoid virulence selection in nematode isolates.  相似文献   

18.
Summary Plants ofSolanum brevidens graft-inoculated with potato leaf roll virus (PLRV) grew vigorously and had a normal healthy appearance. Although presence of the virus was confirmed in all inoculated plants by graft tests to potato and/orDatura stramonium, recovery of PLRV fromS. brevidens PI 218228 usingPhysalis floridana and the aphidMyzus persicae was erratic and only few test seedlings became infected. Ease of recovery of the virus using aphids was not influenced by presence of a continuous graft union with infected potato. Testing ofS. brevidens PI 245763 withM. persicae was not possible due to poor aphid survival on plants of this accession.  相似文献   

19.
A total of 258 Plant Introductions (PI) belonging to 69Solarium species were evaluated in the greenhouse for their reaction to the tobacco veinal necrosis strain of potato virus Y (PVY N). One hundred and thirty-one (50.7%) of the PI accessions produced mosaic symptoms ranging from mild to severe. Local lesion and veinal necrosis symptoms were observed in 19 PI accessions (7.3%) and a variety of other symptoms were observed in another 11 PI accessions (4.2%). Only 97 PI accessions (37.5%) were symptomless carriers of PVYN. PI accession 473505 ofS. sparsipilum and PI accession 498021 ofS. brachycarpum developed local lesions and veinal necrosis with PVYN, but necrotic spots and mosaic with PVYo. Common mechanically-transmitted potato viruses A, S, M, and X did not interfere with PVY symptom development inS. sparsipilum andS. brachycarpum. Thus, PI 473505 and PI 498021 can be used as indicator plants for specific identification of PVYN. PI accession 472819 ofS. chacoense developed local lesions with systemic spread in PVYo, but without systemic spread in PVYN. Thus, this can be used as a differential host plant for PVY strains. Two PI accessions ofS. stoloniferum, PI 160372 and 161171 were immune to PVYN.  相似文献   

20.
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号