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1.
Robert Park Tom Fetch Dave Hodson Yue Jin Kumarse Nazari Mohinder Prashar Zacharias Pretorius 《Euphytica》2011,179(1):109-117
Surveillance of wheat rust pathogens, including assessments of rust incidence and virulence characterization via either trap
plots or race (pathotype) surveys, has provided information fundamental in formulating and adopting appropriate national and
international policies, investments and strategies in plant protection, plant breeding, seed systems, and in rust pathogen
research. Despite many successes from national and regional co-ordination of rust surveillance, few attempts were made to
extend rust surveillance to international or even global levels. The Global Cereal Rust Monitoring System was established
to address this deficiency. It is underpinned by an information platform that includes standardized protocols for methods
and systems used in surveys, preliminary virulence testing, data, sample transmission and management at the field and national
and global levels, and includes two web-based visualization tools. While considerable progress has been made towards a global
system for monitoring variability in the wheat stem rust pathogen, and linking this to the threat posed by this pathogen to
regional wheat production, some challenges remain, including ongoing commitment to support rust surveillance, and the ability
to share and compare surveillance data. 相似文献
2.
A. Morgounov I. Ablova O. Babayants L. Babayants L. Bespalova Zh. Khudokormov N. Litvinenko V. Shamanin V. Syukov 《Euphytica》2011,179(2):297-311
Leaf rust represents the major threat to wheat production in Russia and Ukraine. It has been present for many years and epidemics
of the pathogen occur in different regions on both winter and spring wheat. In some regions there is evidence of more frequent
epidemics, probably due to higher precipitation as a result of climate change. There is evidence that the virulence of the
leaf rust population in Ukraine and European Russia and on winter wheat and spring wheat is similar. The pathogen population
structure in Western Siberia is also similar to the European part, although there are some significant differences based on
the genes employed in different regions. Ukrainian wheat breeders mostly rely on major resistance genes from wide crosses
and have succeeded in developing resistant varieties. The North Caucasus winter wheat breeding programs apply the strategy
of deploying varieties with different types of resistance and genes. This approach resulted in decreased leaf rust incidence
in the region. Genes Lr23 and Lr19 deployed in spring wheat in the Volga region were rapidly overcome by the pathogen. There are continuing efforts to incorporate
resistance from wild species. The first spring wheat leaf rust resistant varieties released in Western Siberia possessed gene
LrTR which protected the crop for 10–15 years, but was eventually broken in 2007. Slow rusting is being utilized in several breeding
programs in Russia and Ukraine, but has not become a major strategy. 相似文献
3.
Genes which confer partial resistance to the rusts in wheat figure prominently in discussions of potential durable resistance strategies. The positional cloning of the first of these genes, Lr34/Yr18 and Yr36, has revealed different protein structures, suggesting that the category of partial resistance genes, as defined by phenotype, likely groups together suites of functionally heterogenous genes. With the number of mapped partial rust resistance genes increasing rapidly as a result of ongoing advances in marker and sequencing technologies, breeding programs needing to select and prioritize genes for deployment confront a fundamental question: which genes or gene combinations are more likely to provide durable protection against these evolving pathogens? We argue that a refined classification of partial rust resistance genes is required to start answering this question, one based not merely on disease phenotype but also on gene cloning, molecular functional characterization, and interactions with other host and pathogen proteins. Combined with accurate and detailed disease phenotyping and standard genetic studies, an integrated wheat-rust interactome promises to provide the basis for a functional classification of partial resistance genes and thus a conceptual framework for their rational deployment. 相似文献
4.
5.
R. N. Sawhney 《Euphytica》1987,36(1):49-54
Summary Variation for resistance toPuccinia graminis f.sp.tritici, P. recondita f.sp.tritici andP. striiformis was induced in theTriticum aestivum cultivar Lalbahadur using nitrosomethyl urea. Variations were isolated from the M2 population in the post-seedling stage in the field when infected with a mixture of races of each of the three rusts. Plants exhibiting simultaneous resistance to stem rust, leaf rust and yellow rust were indentified. Repeated screening in the subsequent generations confirmed the resistance of the mutant lines that are morphologically similar to the parental cultivar. The rust resistance of 20 mutant lines was also confirmed at the seedling stage using individual races of stem rust and leaf rust. The different patterns observed in the mutant lines tested against a wide range of races show that these lines can be used as components of a multiline. The patterns of variation compared with those of the known genes for resistance against the Indian races of the pathogens suggest that the mutations for rust resistance are due to factor different from those already known in bread wheat, providing a broadened genetic base for future breeding programmes. 相似文献
6.
Summary Hexaploid and octoploid tritordeums and their parents Hordeum chilense and Triticum spp. were screened for resistance to isolates of wheat and barley yellow and brown rusts. All H. chilense lines were highly resistant to both wheat and barley brown rust, few lines were susceptible to wheat yellow rust while susceptibility to barley yellow rust was common. In general the resistance of tritordeum is predominantly contributed by the wheat parent and apparently the genes for resistance in H. chilense are inhibited in their expression by the presence of the wheat genome.Abbreviations WYR
wheat yellow rust
- WBR
wheat brown rust
- BYR
barley yellow rust
- BBR
barley brown rust 相似文献
7.
Summary Seedling responses to one Australian isolate of each of the stripe rust, stem rust and leaf rust pathogens were determined for 541 accessions of T. dicoccoides collected from 23 locations in Israel. Resistance to stripe rust was more frequent than resistance to stem rust. Stripe rust responses showed a wide range of variability indicative of a number of genes for resistance. Comparison of the present stem rust data and that reported for the same accessions tested in Israel indicated that different genes were operating in each country. Only moderately resistant responses to stem rust were obtained. This level of resistance is probably inadequate for transfer to commercial wheat cultivars. We found no potentially useful seedling resistance to leaf rust. 相似文献
8.
This paper offers projections of potential effects of climate change on rusts of wheat and how we should factor in a changing
climate when planning for the future management of these diseases. Even though the rusts of wheat have been extensively studied
internationally, there is a paucity of information on the likely effects of a changing climate on the rusts and their influence
on wheat production. Due to the lack of published empirical research we relied on the few published studies of other plant
diseases, our own unpublished work and relevant information from the vast literature on rusts of wheat to prepare this overview.
Three broad areas of potential risks from a changing climate were described: increased loss from wheat rusts, new rust pathotypes
evolving faster and the reduced effectiveness of rust resistances. Increased biomass of wheat crops grown in the presence
of elevated CO2 concentrations and higher temperatures will increase the leaf area available for attack by the pathogen leading to increased
inoculum production. If changed weather conditions were to accelerate the life cycle of a pathogen, the increased inoculum
can lead to severe rust epidemics in many environments. Likewise should the effects of climate change result in more conducive
conditions for rust development there will also be a corresponding increase in the rate of evolution of new pathotypes which
could increase the rate of appearance of new virulences. The effectiveness of some rust resistance genes is influenced by
temperature and crop development stage. Climate change may directly or indirectly influence the effectiveness of some resistance
genes but this can not be ascertained due to a complete lack of knowledge. Since disease resistance breeding is a long term
strategy it is important to determine if any of the important genes may become less effective due to climate change. Studies
must be made to acquire new information on the rust disease triangle to increase the adaptive capacity of wheat under climate
change. Leadership within the Borlaug Global Rust Initiative (BGRI) is needed to broker research on rust evolution and the
durability of resistance under climate change. 相似文献
9.
Stem rust of wheat, caused by Puccinia graminis f. sp. tritici, was under control worldwide for over 30 years by utilizing genetic resistance. The emergence of stem rust in 1998 in eastern Africa in form of race Ug99 and its evolving variants with virulence to many resistance genes were recognized as potential threats to wheat production. In this study we identified genomic regions contributing to putatively durable, adult plant resistance (APR) to wheat stem rust. A recombinant inbred line (RIL) population of 298 lines was previously developed at CIMMYT from a cross between ‘Avocet S’ and ‘Pavon 76’. Pavon 76 has been described to carry APR to stem rust. Avocet S carries the race-specific resistance gene Sr26. A subset of RILs without Sr26 segregated for APR to stem rust race Ug99 when evaluated in Kenya for three years. Single year and joint year analysis by inclusive composite interval mapping using 450 DArT markers identified five quantitative trait loci (QTL) that contributed to the resistance of wheat to stem rust race Ug99. Three of these, including QSr.cim-3B, which probably represents the Sr2 gene, were contributed by Pavon 76 whereas the remaining two QTL were contributed by Avocet S. QSr.cim-3B, or putatively Sr2, on chromosome arm 3BS explained 32 % of the phenotypic variation while the additional QTL in Pavon contributed 24 and 20 %, respectively. Two QTL from Avocet S explained 8 and 6 % of phenotypic variance, respectively. A combination of APR QTL from the two parents resulted in transgressive segregants expressing higher levels of resistance than Pavon 76. Our results indicate that it is possible to accumulate several minor resistance genes each with a small to intermediate effect resulting in a variety that exhibits negligible disease levels even under high stem rust pressure. 相似文献
10.
Summary In former Czechoslovakia virulence of rusts attacking wheat was studied since the sixties. Since the same time genes for resistance in the registered cultivars were identified. The role of Berberis and Thalictrum as alternate hosts for stem rust and leaf rust, respectively, was investigated as well. Determined changes of virulence in rust populations could only partially be ascribed to changes of resistance genes in the grown cultivars. Unnecessary genes for virulence had no negative effect on the fitness of the pathogen. All tested samples of aeciospores from barberries attacked rye, not wheat. None of Thalictrum species occurring in the Czech and Slovak Republics was found to host wheat leaf rust. However, the sexual stage of wheat stem rust and wheat leaf rust could be induced on Berberis vulgaris and Thalictrum speciosissimum, respectively. General epidemiological conclusions are drawn from the results and experience of the last 35 years. 相似文献
11.
小麦野生近缘植物具有优良的抗病特性,是改良普通小麦的宝贵遗传资源,是基因改良和培育高产、优质和高抗病性小麦的基础。为此,主要对小麦赤霉病、白粉病、叶锈病、条锈病、秆锈病等小麦主要病害的发生及危害情况进行简述,阐述了利用小麦野生近缘植物进行小麦主要病害的抗病性鉴定研究进展,包括苗期及成株期鉴定、温室及田间试验、分子标记辅助鉴定等,指出了小麦近缘野生植物与普通小麦直接或间接杂交转移优异基因情况,并对其发展前景进行了展望。 相似文献
12.
Z. M. Ziyaev R. C. Sharma K. Nazari A. I. Morgounov A. A. Amanov Z. F. Ziyadullaev Z. I. Khalikulov S. M. Alikulov 《Euphytica》2011,179(1):197-207
Wheat is the most important cereal in Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) and the
Caucasus (Armenia, Azerbaijan and Georgia). Stripe rust, caused by Puccinia striiformis f. sp. tritici is considered the most important disease of wheat in Central Asia and the Caucasus (CAC). Although stripe rust has been present
in the region for a long time, it has become a serious constraint to wheat production in the past 10 years. This is reflected
by the occurrence of five epidemics of stripe rust in the CAC region since 1999, the most recent in 2010. Several wheat varieties
occupying substantial areas are either susceptible to stripe rust or possess a low level of resistance. Information on the
stripe rust pathogen in terms of prevalent races and epidemiology is not readily available. Furthermore, there is an insufficient
understanding of effective stripe rust resistance genes in the region, and little is known about the resistance genes present
in the commercial varieties and advanced breeding lines. The deployment of resistant varieties is further complicated by putative
changes in virulence in the pathogen population in different parts of the CAC. Twenty four out of 49 improved wheat lines
received through international nurseries or other exchange programs showed high levels of resistance to stripe rust to local
pathogen populations in 2009. Fifteen of the 24 stripe rust resistant lines also possessed resistance to powdery mildew. It
is anticipated that this germplasm will play an important role in developing stripe rust resistant wheat varieties either
through direct adoption or using them as parents in breeding programs. 相似文献
13.
Overcoming chronic malnutrition in a future warming world: the key importance of mungbean and vegetable soybean 总被引:1,自引:0,他引:1
J. D. H. Keatinge W. J. Easdown R. Y. Yang M. L. Chadha S. Shanmugasundaram 《Euphytica》2011,179(1):129-141
Stripe rust, caused by Puccinia striiformis, has been an important disease of wheat, barley, rye, triticale and certain graminaceous hosts for centuries. The significance
of the disease on cultivated cereals has waxed and waned according to the vagaries of climate, inoculum levels and susceptible
varieties. A progressive understanding of pathogen biology has revealed levels of specialisation between and within host groups,
and these had varying impacts on the hosts concerned. The most economically important form is P. striiformis f. sp. tritici (Pst), the causal pathogen of stripe (yellow) rust of wheat, which is the major focus of this paper. The recent discovery of the
perfect stage of Pst on Berberis spp. will encourage further work to uncover the potential importance of the sexual stage in pathogen biology in regions where
Berberis spp. occur. A review of the evolution of pathotypes within Pst over the past 50 years reveals recurrent pandemics emanating from a combination of specific virulence in the pathogen population,
wide scale cultivation of genetically similar varieties, and agronomic practices that led to high yield potential. When these
factors operate in concert, regional stripe rust epidemics have proven to be dramatic, extensive and serious in terms of the
magnitude of losses and the economic hardships endured. A review of these epidemics suggests that little progress has been
made in containing the worst effects of epidemics. The current status of stripe rust was gauged from a survey of 25 pathologists
and breeders directly associated with the disease. It was evident that Pst remains a significant threat in the majority of wheat growing regions of the world with potential to inflict regular regional
crop losses ranging from 0.1 to 5%, with rare events giving losses of 5–25%. Regions with current vulnerability include the
USA (particularly Pacific North West), East Asia (China north-west and south-west), South Asia (India, Pakistan, Nepal), Oceania
(Australia, New Zealand), East Africa (Ethiopia, Kenya), the Arabian Peninsula (Yemen) and Western Europe (east England).
The resources deployed to contain the worst effects of Pst will need to find a balance between training a new generation of breeders and pathologists in host-pathogen genetics, and
an investment in infrastructure in IARCs and NARs. 相似文献
14.
Andrzej Gąsowski 《Euphytica》1990,48(3):211-214
Summary The relation between flag leaf position and leaf rust severity was investigated in field experiments. Different leaf angles were obtained by attaching ends of flag leaves to strings stretched at different heights along wheat rows. Leaves with angles between lamina and stem of 0° and 45° were significantly less diseased than leaves with horizontal and pendulous positions. In the experiment with seedlings, spore settling and uredia number were significantly lower on erect than on horizontal leaves. The influence of wheat leaf position changes on leaf rust severity was discussed. It has been suggested that breeding of wheat cultivars with erect leaves can improve their resistance to airborne pathogens. 相似文献
15.
Past,present and future opportunities in breeding for disease resistance,with examples from wheat 总被引:6,自引:0,他引:6
Roy Johnson 《Euphytica》1992,63(1-2):3-22
Summary This introductory chapter contains some general comments about plant breeding and breeding for disease resistance. The use of disease resistant crop plants is an environmentally favourable method of controlling disease but the process of breeding for disease resistance is subject to several constraints. Among them is the variability of pathogens in relation to host resistance. Some parts of this variation can be resolved into gene-for-gene interactions, but the boundaries within which such interactions can be detected are not sharp. The discussion of this variation is illustrated by reference to some important diseases of wheat, especially yellow rust, septoria and eyespot. The objective of obtaining durable resistance is discussed and some contributions of new genetical and molecular techniques to breeding for resistance are considered. It is suggested that new technology will enhance breeding for disease resistance but that established techniques of plant breeding will remain relevant and important. 相似文献
16.
Practical breeding for durable resistance to rust diseases in self-pollinating cereals 总被引:3,自引:0,他引:3
R. Johnson 《Euphytica》1978,27(2):529-540
Summary The rust pathogens of cereals exist as populations of races that differ in their ability to attack various varieties. Varieties that are resistant when first released often become susceptible later due to the spread of previously undetected races but the time taken for this to occur in very variable. It often occurs so rapidly as to curtail the commercial use of otherwise satisfactory varieties.Some varieties, however, are widely grown for many years and remain adequately resistant to the prevalent rust diseases. They may aptly be described as having durable resistance. This durable or long-lasting resistance can be detected without any assumptions about, or detailed knowledge of, whether durability depends on any particular mechanisms of resistance, on various degrees of racespecificity or on many or few genes. Cappelle-Desprez is given as an example of a wheat variety with durable resistance to yellow rust.The most powerful test for the detection of durable resistance occurs when a variety is widely grown commercially for several years. A much weaker test is obtained by growing varieties in small disease nursery plots even when the test is repeated for several years. Usually, resistance which is durable is also partial or incomplete. Often, however, partial resistance of wheat to yellow rust has not been durable. Thus the observation that resistance is partial is not, of itself, a satisfactory criterion for the detection of durable resistance.It is suggested that the most obvious sources of durable resistance for use in breeding programmes are varieties which have been widely grown and have displayed this character. The transfer of such resistance during breeding may be achieved if the creation or incorporation of higher levels of resistance that have not been tested for durability is avoided. It should then be possible to derive resistance from the durably. resistant parent. Methods of achieving this are discussed. 相似文献
17.
Twenty-one bread-wheat entries were selected after careful screening for complete or near-complete resistance to yellow rust (Puccinia striiformis), stem rust (P. graminis), and leaf rust (P. recondita). In 1987, the 21 entries were intercrossed in a near-half diallel scheme. The resulting 190 F2 populations were advanced to F7 under selection for complete resistance to the three rusts and for good agronomic types. In 1992 the 21 parents and 140 selected F7 lines were assessed for their resistance to the three rusts. Of the 21 parents, 12 showed a breakdown of yellow rust resistance, five a breakdown of stem rust resistance and two a breakdown of leaf rust resistance. In addition, several of the 140 selected F7 lines, all still resistant in F6, had become susceptible to one or more of the rusts. It appears that a progression towards more complex races, especially of yellow rust, is inevitable for the wheat-cereal rust patho-systems when the selection is for complete or near-complete resistance. 相似文献
18.
Summary Seedling resistance to wheat stem rust was determined in populations of wild emmer wheat, Triticum dicoccoides, and characterized by means of ecological factors and allozyme genotypes. Reactions to wheat stem rust were studied in 102 single plant accessions of T. dicoccoides from ten populations by inoculation with Puccinia graminis tritici race 14, isolate GSR-739. Six populations displayed different degrees of response polymorphism with reactions ranging from high resistance to complete susceptibility, whereas four populations contained only susceptible plants. In some of the accession, unexplained intrasib variation in resistance and intraplant variation of infection-types were found. Resistance to stem rust was negatively correlated with two ecological factors, altitude and number of Sharav (hot-dry) days which are unfavorable to disease development. Variation in stem rust response was shown to exist in ecogeographic regions where climatic variables enhanced the development of the fungus, conceivably maintained by natural selection. Likewise, allozyme genotypes, single or in multiple loci combinations, appeared to be associated with resistance or susceptibility to rust. Such association need to be verified by genetic studies in order to become established as useful markers. 相似文献
19.
20.
Seedling resistance to stem rust race Ug99 and marker analysis for Sr2, Sr24 and Sr31 in South African wheat cultivars and lines 总被引:1,自引:0,他引:1
The appearance and spread of races of Puccinia graminis f. sp. tritici with virulence for the Sr31 resistance gene has renewed interest in breeding for durable resistance to stem rust of wheat. Since the occurrence of stem
rust has been low in South Africa until the detection of race TTKSF in 2000, breeding for resistance to this disease has not
been a primary objective. The aim of this study was to test bread wheat cultivars and lines at the seedling stage for their
infection response to stem rust, thus determining their level of resistance or vulnerability. A collection of 65 bread wheat
entries was tested with one USA race, two Eastern African races, and three South African races of P. graminis f. sp. tritici. The Eastern African and South African races all belong to the Ug99 lineage. The cultivars Duzi, Caledon, Elands, PAN 3364,
PAN 3191, SST 047, SST 399, and Steenbras produced resistant infection types (IT < 3) to all races. The molecular marker Sr24#50
indicated the presence of Sr24 in 12 entries. In cultivars resistant to TTTTF, TTKSF, and TTKSP but susceptible to TTKSK and PTKST, the iag95 DNA marker
indicated the presence of Sr31 in five wheat lines. Using the cleaved amplified polymorphic sequence marker csSr2, Sr2 was detected in PAN 3377, Inia, and Steenbras. Few South African wheat cultivars appear to have a broad-based resistance
to stem rust, as 88% of the entries were susceptible as seedlings to at least one of the races tested. Diversification of
resistance sources and more directed breeding for stem rust resistance are needed in South Africa. 相似文献