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1.
Ingo Hein Paul R. J. Birch Sarah Danan Véronique Lefebvre Damaris Achieng Odeny Christiane Gebhardt Friederike Trognitz Glenn J. Bryan 《Potato Research》2009,52(3):215-227
Cultivated potato is susceptible to many pests and pathogens, none of which is more of a threat to potato agriculture than
the late blight disease, caused by the oomycete Phytophthora infestans (Mont.) de Bary. To date all efforts to thwart this most adaptive of pathogens have failed, and early attempts to deploy
‘R genes’ introgressed from the wild Mexican hexaploid Solanum demissum ended in abject failure. With the advent of facile gene mapping and cloning, allied to knowledge of plant resistance gene
structure, renewed efforts are leading to mapping and isolation of new sources of late blight resistance in potato wild species,
many of which are being performed under the auspices of the BIOEXPLOIT project (Sub-project 2). We document recent advances
in late blight resistance gene mapping and isolation, and postulate how these genes, allied to knowledge of pathogen effectors
and their recognition specificity, may greatly enhance our chances of halting the progress of late blight disease in potato
crops worldwide. 相似文献
2.
Cisgenesis Does Not Solve the Late Blight Problem of Organic Potato Production: Alternative Breeding Strategies 总被引:3,自引:2,他引:1
Average potato yields in Dutch organic farming systems vary from 15 to 29 Mg/ha and are limited by low input of nitrogen and
severe late blight attacks caused by the oomycete Phytophthora infestans. Under Dutch late blight regulations it is mandatory to kill the haulm at 7% infestation. The late blight attacks have been
so early in the organic potato production of the past few years that its acreage is now gradually decreasing whereas consumer
demand is increasing. Agronomic control strategies have limited success. First priority lies in breeding for highly resistant
varieties to safeguard organic potato production in the Netherlands. Cisgenesis, however, is not an option for the organic
sector. Although the product of cisgenesis does not contain genes from non-crossable species it is a result of a genetic engineering
process which is excluded from use in organic agriculture. As the principles and standards of organic agriculture are process-based,
cisgenesis does not comply with the norms and standards of organic agriculture. The arguments of the organic sector go well
beyond the alleged risks of the gene technology and relate to the technology itself. Breeding at DNA-level, instead of at
whole-plant level, violates the integrity of life as described in the concept of naturalness. The Dutch organic sector is
now aiming at increasing the traditional breeding activities including the participation of farmer-breeders in close cooperation
with the formal breeding companies. Additional selection methods need to be developed to include required traits other than
late blight resistance, such as nutrient efficiency. Recently two varieties have been released with high resistance against
late blight based on introgressing genes from Solanum bulbocastanum. Organic agriculture can benefit from marker assisted breeding to achieve adequate pyramiding of different, new sources of
resistance. 相似文献
3.
In an experimental breeding scheme to improve late blight (Phytophthora infestans) and white potato cyst nematode (Globodera pallida) resistance of tetraploid potato over three generations of crossing and selection, 15 clones survived the final selection,
and these were derived from 15 great-grandparents. There was no direct selection for resistance to Potato virus Y (PVY), but 14 out of the 15 great-grandparents were resistant to PVY and three had extreme resistance. Thirteen of the 15
descendants had PVY resistance and one extreme resistance. This was within the range expected for a random (unselected) sample
from the genotypes of the great-grandparents. Hence, we found no evidence for any positive or negative association between
PVY resistance and the attributes selected. The conclusion is that laborious selection is not required in every generation
when many parents have PVY resistance, including some with more than one copy of a PVY resistance gene or resistance at more
than one locus. However, in the future, determining the major virus resistance genes present in potential parents in each
generation using diagnostic molecular markers would prevent susceptible × susceptible crosses being made and maximise the
number of resistant × resistant ones. 相似文献
4.
Marker-assisted Breeding for Disease Resistance in Potato 总被引:1,自引:1,他引:0
A. Carrasco J. E. Chauvin B. Trognitz A. Pawlak O. Rubio-Covarruvias E. Zimnoch-Guzowska 《Potato Research》2009,52(3):245-248
Sub-project 5 of BIOEXPLOIT aims to design durable disease resistance through marker-assisted breeding by converting existing
markers for high-throughput application, developing and validating high-throughput marker technologies and pyramiding major
R genes and/or quantitative trait loci into elite material. Activities include (1) the fine mapping of the quantitative trait
locus PiXspg which accounts for a large proportion of the variation in late blight resistance, (2) converting SNP-based markers and an
AFLP marker to easy-to-use-markers, (3) testing of progenies with combined sources of late blight resistance for presence
of R genes and agronomic features, (4) backcrossing new sources of resistance to S. tuberosum and molecular screening of breeding materials with marker GP94 linked with gene Rpi-phu1 conferring late blight resistance, (5) evaluating potato clones with enhanced resistance against Phytophthora infestans under field conditions of Toluca (México), and (6) developing populations and marker-assisted breeding for disease resistance. 相似文献
5.
Debate on the Exploitation of Natural Plant Diversity to Create Late Blight Resistance in Potato 总被引:1,自引:1,他引:0
This paper reports on a debate on intriguing propositions relating to the scientific, agronomic, societal and economic impact
of the BIOEXPLOIT project, focusing on late blight resistance in potato. It discusses (i) whether identifying pathogen effectors
will facilitate selecting durable R genes, (ii) whether breeding for durable late blight resistance requires deploying Rpi (for Resistance to P
hytophthora
i
nfestans) genes, (iii) whether breeding strategies and cultural practices determine the durability of new resistance genes, (iv) whether
marker-assisted breeding for Phytophthora infestans resistance is already in the stage of adoption, (v) to what extent genetically-modified organism technology can advance realizing
late-blight resistant potato cultivars, and (vi) whether modifying R genes will result in novel broad spectrum resistance. 相似文献
6.
Societal Costs of Late Blight in Potato and Prospects of Durable Resistance Through Cisgenic Modification 总被引:6,自引:4,他引:2
A. J. Haverkort P. M. Boonekamp R. Hutten E. Jacobsen L. A. P. Lotz G. J. T. Kessel R. G. F. Visser E. A. G. van der Vossen 《Potato Research》2008,51(1):47-57
In the European Union almost 6 Mha of potatoes are grown representing a value of close to €6,000,000,000. Late blight caused
by Phytophthora infestans causes annual losses (costs of control and damage) estimated at more than €1,000,000,000. Chemical control is under pressure
as late blight becomes increasingly aggressive and there is societal resistance against the use of environmentally unfriendly
chemicals. Breeding programmes have not been able to markedly increase the level of resistance of current potato varieties.
New scientific approaches may yield genetically modified marker-free potato varieties (either trans- and/or cisgenic, the
latter signifying the use of indigenous resistance genes) as improved variants of currently used varieties showing far greater
levels of resistance. There are strong scientific investments needed to develop such improved varieties but these varieties
will have great economic and environmental impact. Here we present an approach, based on (cisgenic) resistance genes that
will enhance the impact. It consists of five themes: the detection of R-genes in the wild potato gene pool and their function related to the various aspects in the infection route and reproduction
of the late blight causing pathogen; cloning of natural R-genes and transforming cassettes of single or multiple (cisgenic) R-genes into existing varieties with proven adaptation to improve their value for consumers; selection of true to the wild
type and resistant genotypes with similar qualities as the original variety; spatial and temporal resistance management research
of late blight of the cisgenic genetically modified (GM) varieties that contain different cassettes of R-genes to avoid breaking of resistance and reduce build-up of epidemics; communication and interaction with all relevant stakeholders
in society and transparency in what research is doing. One of the main challenges is to explain the different nature and possible
biological improvement and legislative repercussions of cisgenic GM-crops in comparison with transgenic GM-crops. It is important
to realize that the present EU Directive 2001/18/EC on GM crops does not make a difference between trans- and cisgenes. These
rules were developed when only transgenic GM plants were around. We present a case arguing for an updating and refinement
of these rules in order to place cisgenic GM-crops in another class of GM-plants as has been done in the past with (induced)
mutation breeding and the use of protoplast fusion between crossable species. 相似文献
7.
8.
Summary Increased virulence associated with fungicide resistance and variablePhytophthora infestans populations has been recorded in many potato growing regions with enormous economic effects. The current emphasis on disease
management in East Africa includes the use of potato varieties with durable resistance to late blight. Seven promising clones
from Population B with quantitative resistance (no R-genes), two advanced clones from Population A (with Rgenes) and three
control varieties were grown for three cropping seasons in order to determine their reaction and stability of late blight
resistance. Late blight occurrence was detected in all cropping seasons. The analysis of variance of disease data (AUDPC)
for genotypes, locations x seasons was highly significant (P<0.001) indicating the differential response of the geno-types
and the need for stability analysis. The Additive Main Effects and Multiplicative Interaction (AMMI) statistical model, showed
that the most stable genotypes were 392127.256, 381471.18, 387121.4 (resistant) and 391049.255 (susceptible to late blight).
Within environments, the ranking of genotypes was not consistent. The variety Kabale was ranked as the most susceptible genotype
while clone 381471.18 and Rutuku were ranked the most resistant. Selective deployment of resistant and stable varieties is
critical in minimizing economic loss and damage attributed to late blight in low input farming systems. 相似文献
9.
In order to optimize potato crop management in organic farming systems, knowledge of crop growth processes in relation to
limitations and reductions by nitrogen (N) and disease is necessary. This paper examines the effect of different prevention
measures (seed tuber pre-sprouting, choice of cultivars: resistance to Phytophthora infestans; earliness of tuber initiation) against disease-related constraints on yields, depending on the N-mediated growing conditions
of organic potato crops. Under conditions of a relatively high N supply, accelerating the early development and tuber initiation
of potato crops by seed tuber pre-sprouting (yield increase of c. 18–23%) or the selective choice of cultivars with an earlier
tuber initiation (yield increase of c. 0–21%) are the most effective strategies in combating late blight. They bring forward
the crop development c. 7–10 days, escaping the negative impact of the fungus on tuber growth. Under conditions of a relatively
low N supply, these strategies do not affect final tuber yield. The reason for the differences of the effect depending on
N supply of the crops is, that the lower the N supply, the shorter the period of time over which tuber growth takes place,
independent of whether P. infestans becomes severe or not. Tuber growth of organic crops low in N has mostly ceased by the time late blight becomes potentially
important for limiting yield, with the consequence that preventative measures against P. infestans are meaningless. Surprisingly, the level of cultivar haulm resistance to late blight did not affect tuber yields in years
with an early and strong late blight development. Probably, the positive effect of a longer resistance to the fungus (c. 1 week)
was counterbalanced by a later tuber initiation (also c. 1 week). In years with a moderate late blight incidence, less susceptible
cultivars were able to produce higher tuber yields on fields with a lower N availability (c. 17–20%), probably due to higher
N use efficiency and a better match of N mineralization and N uptake. Under conditions of a relatively high N supply, the
tested cultivars with a higher haulm resistance to late blight were not able to improve tuber yields. 相似文献
10.
Potato late blight caused by the oomycete Phytophthora infestans is a devastating disease of potato worldwide. Most of the potato cultivars grown in conventional agriculture are susceptible, or at best moderately resistant, and require frequent applications of fungicides to avoid heavy yield losses.In field trials spanning four years, we have investigated the effect of potassium phosphite, an inorganic salt on potato late blight. Potassium phosphite is known to induce defence responses in potato and to also have direct toxic effects on oomycetes, which in turn counteract late blight and tuber blight development. However, the use of this salt is not yet implemented and approved in European potato cultivation. We compared the effect of phosphite alone with fungicides currently used in Swedish potato cultivation. We also investigated the combined use of potassium phosphite and reduced doses of fungicides. Table potato cultivars and starch potato cultivars with different levels of resistance were used.We found that potassium phosphite in combination with reduced doses of fungicides results in the same level of protection as treatments with the recommended full dose of fungicides. These combined treatments reduce the need of traditional fungicides and may also decrease the selection pressure for fungicide resistance development in the pathogen. In relatively resistant starch potato cultivars using phosphite alone gave sufficient protection against late blight. Furthermore, in starch potato a combination of phosphite and fungicides at two-week intervals provided similar protection to weekly applications of fungicide at the recommended dose. Foliar treatment with phosphite also gave protection against tuber blight at similar levels to that of the best-performing fungicide. Our data suggests that potassium phosphite could be used in potato cultivation in temperate regions such as in Sweden, at least in combinations with reduced rates of fungicides. The implementation of the use of phosphite in practical potato crop protection as part of an IPM strategy is discussed. Doses, intervals and combinations could be adjusted to the level of cultivar resistance. 相似文献
11.
C. Cerato L. M. Manici S. Borgatti R. Alicchio R. Ghedini A. Ghinelli 《Potato Research》1993,36(4):341-351
Summary Cells of seven potato cultivars were selectedin vitro with culture filtrate (CF) ofPhytophthora infestans (Mont.) de Bary. Regenerated plants were tested for late blight resistance. The aim of the study was to check the efficacy
of CF in the selection of potatoes for resistance to late blight and to evaluate the effects of additive factors on general
resistance. One selection cycle, applied to a cell culture system, selected cells resistant to toxic metabolites of CF.In vivo screening of clones regenerated from selected cells was done in two steps: on whole plants, assessing foliage late blight,
and on detached leaves, assessing single factors of horizontal resistance.
In general, the frequency of resistant variants selected with CF did not differ from that of resistant somaclonal variants.
Nevertheless, high concentrations of CF in the growth medium seemed to induce an improvement of some partial resistance factors
as compared with the source plants. 相似文献
12.
For organic potato producers the two main challenges are disease and nutrient management. Both factors are limited by regulations that on the one hand prohibit the use of chemical fertilisers, especially nitrogen and, on the other hand, most synthetic pesticides. Late blight, caused by Phytophthora infestans is commonly thought to be the factor most limiting yield. However, because there is no really effective fungicide available to control late blight, there are virtually no yield loss data available for organic farming conditions. In this paper the state of the art of organic potato management with respect to disease and nutrient management is summarised. In a second part, the interactive effects of N-availability in the soil, climatic conditions and late blight were studied in the presence and absence of copper fungicides from 2002–2004 for the mid-early main-crop potato cv. Nicola. From the experimental work it became clear that copper fungicides in most cases do slow down epidemics adding an average of 3 days to the growth duration. However, only 30% of the variation in yield could be attributed to disease reduction. A model including disease reduction, growth duration and temperature sum from planting until 60% disease severity was reached, and soil mineral N contents at 10 days after emergence could explain 75% of the observed variation in yield. However, the model failed when N-supply was extremely high. The implications of the results on the management of organic potatoes with respect to cultivar choice, nutrient and disease management are discussed. In conclusion, several points emerge from the results: In organic farming, yields are foremost limited by nutrient availability in spring and early summer. The effects of late blight on yields may often be overestimated and cannot be deducted from results in conventional farming because of the strong interaction with nutrient status. Resistance clearly remains the most important strategy against late blight in organic potato production. However, as important or even more important than resistance is the early development and bulking behaviour and the ability of a cultivar to make use of organic nutrients efficiently. In the absence of efficient organic pesticides it is possible to reduce blight pressure to a certain extent by arranging the crop in small narrow fields perpendicular to the main wind direction neighboured either by non-hosts or completely resistant potatoes. 相似文献
13.
William W. Kirk Kimberly J. Felcher David S. Douches Brendan A. Niemira Raymond Hammerschmidt 《American Journal of Potato Research》2001,78(4):319-322
Late blight is an important disease of potato(Solanum tuberosum L.) worldwide, and therefore, many potato-breeding programs have prioritized the development of late blight-resistant potato cultivars. Although the emphasis has been to enhance foliar resistance, it is also necessary to evaluate tuber late blight resistance in new breeding lines and new sources of late blight resistance. We report here on the assessment of foliar and tuber resistance and the correlation between these aspects of resistance in a sample of Michigan State University potato breeding lines. Two MSU breeding lines had significantly less infected foliage than the susceptible check cultivars. Tuber susceptibility was significantly different (P < 0.05) only between the most susceptible and the least susceptible breeding lines/cultivars. Foliar and tuber susceptibility to potato late blight were not correlated as low tuber susceptibility was associated both with extremely low (e.g., MSG274-3) and high (e.g., MSE202-3Rus) foliar susceptibility. 相似文献
14.
Summary Tests for systemic induced resistance (SIR) to late blight were performed with different potato cultivars in field trials
and in growth chamber experiments.
The non-pathogenPhytophthora cryptogea (Pc) and salicylic acid (Sa) were used as inducer agents. In the field, plants were naturally infected byPhytophthora infestans while the indoor plants were inoculated. The degree of SIR obtained varied with the cultivar used and also with the type
of inducer. For example in the field the susceptible cv. St. Cecilia had enhanced resistance with Pc whereas Sa caused increased
susceptibility. Inbred resistant cvs acquired increased resistance after treatment with Sa.
In a separate pilot experiment in a growth chamber, Sa at two different concentrations was injected into potato seed tubers
before planting. The higher Sa concentration increased resistance in genetically resistant cultivars while the lower Sa concentration
brought about increased susceptibility. 相似文献
15.
M. Van Oijen 《Potato Research》1991,34(2):123-132
Summary Potato cultivars of different maturity classes and levels of resistance toPhytophthora infestans were grown under several disease intensities in three field trials. Seasonal courses of ground cover by green foliage and
final tuber yields were determined. Light use efficiencies (LUE) were calculated from regression analyses of yield on cumulative
light interception.
Late blight reduced tuber yields by decreasing cumulative light interception without affecting LUE. No differences in LUE
between cultivars or cultivar classes were detected. Therefore, the maintenance of green leaf area is important when breeding
potatoes for optimal performance in the presence of late blight.
The results support the hypothesis that the correlation between lateness and reported resistance of potato cultivars is due
to the vigorous foliage growth of late cultivars. 相似文献
16.
Summary Phenylamide-based fungicides were reintroduced to the Irish market in 1985. Mixtures of phenylamides and mancozeb were recommended
for no more than 3 sprays in potato late blight control programmes with the last systemic spray to be applied not later than
31 July. Samples of potato foliage infected withP. infestans were collected from the main potato growing areas in Ireland over a five-year period starting in 1985. Using the floating
disc method, 11% of the crops sampled in 1985 were found to have phenylamide-resistant strains ofP. infestans present. The number of crops with resistant strains increased rapidly up to 1988 when 83% of the crops sampled had resistance.
Factors affecting the distribution of resistance and the efficacy of a phenylamide-based spray programme are discussed. 相似文献
17.
Summary In this paper we present observations made during three years in a potato field in Sweden that indicated the presence of soil
borne inoculum ofPhytophthora infestans. In 1994, a fungicide trial against late blight was left in the field with various degrees of late blight infection. In 1995,
cereals was grown in the field. In 1996, certified potato seed tubers were planted and blight appeared early in the season
in a pattern corresponding to the heavily infected areas in 1994. No volunteer potato plants were found in 1995 or 1996. Both
mating types A1 and A2 were isolated in 1996 and 1997 and oospores were found in leaves, stems as well as in stolons. 相似文献
18.
Summary This contribution presents highlights of the oral and poster presentations in the various sessions of the 14th Triennial Conference of the European Association for Potato Research, held in Sorrento, Italy, May 1999. It is based on the
reports of the session chairpersons and the book of abstracts. The paper reports the progress made in many aspects of potato
research, but also stresses the need for further collaborative work, especially in the fields of molecular physiology, marker
assisted breeding, control of late blight, potato tuber moth and other pests and diseases, stress physiology and stress resistance,
and sustainable cropping systems with both short and long cycle potato crops. 相似文献
19.
20.
Modern potato breeding requires over 100,000 seedlings per new variety. Main reasons are (1) the increasing number of traits
that have to be combined in this tetraploid vegetatively propagated crop, and (2) an increasing number of traits (e.g., resistance
to biotic stress) originates from wild species. Pre-breeding by introgression or induced translocation is an expensive way
of transferring single traits (such as R-genes, coding for resistance to biotic stress) to the cultivated plant. The most important obstacle is simultaneous transfer
of undesired neighbouring alien alleles as linkage drag. Stacking several genes from different wild sources is increasing
this linkage drag problem tremendously. Biotechnology has enabled transformation of alien genes into the plant. Initially,
transgenes were originating mainly from microorganisms, viruses or non-crossable plant species, or they were chimeric. Moreover,
selection markers coding for antibiotic resistance or herbicide resistance were needed. Transgenes are a new gene source for
plant breeding and, therefore, additional regulations like the EU Directive 2001/18/EC were developed. Because of a strong
opposition against genetic modification of plants in Europe, the application of this Directive is strict, very expensive,
hampering the introduction of genetically modified (GM) crops and the use of this technology by small and medium-sized enterprises
(SMEs). Currently, GM crops are almost the exclusive domain of multinationals. Meanwhile, not only transgenes but also natural
genes from the plant species itself or from crossable plant species, called cisgenes, are available and the alien selection
genes can be avoided in the end product. This opens the way for cisgenic crops without alien genes. The existing EU directive
for GM organisms is not designed for this new development. The cisgenes belong to the existing breeders’ gene pool. The use
of this classical gene pool has been regulated already in agreements regarding breeders’ rights. We are proposing a step by
step approach starting with a crop and gene specific derogation and monitoring towards a general exemption of cisgenic plants
from the Directive. Two examples, i.e. development of cisgenic potato for resistance to Phytophthora infestans and cisgenic apple for resistance to Venturia inaequalis are discussed shortly for illustration of the importance of cisgenesis as a new tool for traditional plant breeding. Cisgenesis
is simplifying introgression and induced translocation breeding tremendously and is highly recommended for SMEs and developing
countries. 相似文献