Pdf assessing genetic diversity in peronosclerospora. Identification of downy mildew resistance gene candidates. Sclerophthora macrospora is the only downy mildew pathogen on maize under growing conditions in slovenia. Shaw is a major impediment to maize production and productivity. The scientific and technical content of this document is current to the date published and all efforts. Diseases in maize plant diseases biology discussion. Control of sorghum downy mildew peronosclerospora sorghi of. Age of the maize plant is an important factor in infection 25. Whether you grow ornamental plants or fruits and vegetables, there are forms of downy mildew which might develop in your garden. Seed transmission of maize downy mildew peronosclerospora. These are two of several downy mildew diseases that occur in china, india, indonesia, nepal, pakistan. Sorghum downy mildew sdm caused by the oomycete, peronosclerospora sorghi weston and uppal c.
In this study, we analyzed the quantitative trait loci qtls involved in resistance to peronosclerospora sorghi sorghum dm, p. Look for the yellow to white stripes, and the white downy growth that occurs on both sides of the leaves. Maize zea mays, oats, sugarcane, wild sugarcane, sorghum. Ten downy mildew dm diseases are identified on maize. Identifying genomic regions qtls, contributing to sdm resistance will aid in a markerassisted resistant breeding program. Response to selection for downy mildew peronosclerospora. Identification of downy mildew resistance gene candidates by. Mapping of qtl for downy mildew resistance in maize. Results obtained from this research provides a good explanation for frequent breakdown of resistance in downy mildewresistant cultivars and is essential for devising more effective strategies to reduce the impact of downy mildew in maize.
Biological control of downy mildew of maize caused by. Seed transmission of maize downy mildew peronosclerospora sorghi in nigeria v. All the peronoslerospora incited diseases are of old world origin, three of which namely, p. The potential use of dna based molecular techniques in the. Wt plants showed severe symptoms of downy mildew, with angular chlorotic lesions throughout the foliage fig 5a, red stars. International symposium on downy mildew of maize by hiroshi fuji department of plant pathology and entomology, national institute of agricultural science downy mildew is one of the most impor tant diseases of maize, sugarcane, and sor ghum in tropical and subtropical countries. Recovery plan for philippine downy mildew and brown stripe.
Unraveling the genetic diversity of maize downy mildew in indonesia. Epidemiology of downy mildew diseases of maize, sorghum. Csivp functions in vasculature development and downy. Pale green to yellow or brown areas usually develop on the upper leaf surface opposite the downy growth. Do not plant maize close to sugarcane in case of crosscontamination. Philippine downy mildew of maize pdm, caused by the oomycete peronosclerospora philippinensis and brown stripe downy mildew bsdm caused by sclerophthora. Seed transmission of maize downy mildew british society for plant. Cultivars of all these genera, except echinochloa sp. Studies on downy mildew of maize in indonesia with special reference to the perennation of the fungus.
Downy mildew on sweet corn is one of these diseases, a fungal infection that can stunt plants and reduce or destroy the harvest. On the undersides, these areas are covered with white to grayish, cottonlike fungi. Seed treatment with metalaxyl at 4 g kg controlled brown stripe downy mildew sclerophthora rayssiae var. A variety of dm strains have been reported, and the resistance to them is polygenically controlled. Efforts to control the disease by using resistant maize varieties and fungicides often did not give the expected results, this might be due to the variations. Pdf unraveling the genetic diversity of maize downy mildew. None of the downy mildew diseases originated on maize. Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildew dm is a major disease of maize that causes significant yield loss in subtropical and tropical regions around the world. The downy mildews of maize, sorghum and pearl millet are among the most destructive diseases in the tropics and subtropics. Mycelial hyphae growing intercellularly in all parts of host except roots, branched, slender, approx. Brown stripe downy mildew sclerophthora rayssiae var.
Three downy mildew diseases have been reported on corn in the united states. Disease symptoms appear late in the season, infected seeds remain symptomless, and the myriad of fungi inhabiting maize tissue make isolation. Forming linear or irregular whitish yellow to pale spots, often entirely discolouring the leaves and deforming the host. Growing maize in nigeria choice of land any well drained sandy loam or loamy soil can be used for planting maize but if in doubt, contact your nearest extension office or agroservice center. Cardwell international institute of tropical agriculture, pmb 5320, oyo rd, ibadan, nigeria in an area of nigeria where downy mildew of maize is present, histological assessment of maize seed revealed the. Downy mildew is one of the major diseases in maize that may decrease maize production in indonesia. Fortunately, however, it rarely affects soybean productivity in wisconsin. Telle et al 2011 has discovered one downy mildew pathogen species, i. The disease is caused by an oomycete or water mould, not a fungus.
Sorghum downy mildew sdm, caused by obligate biotrophic fungi peronosclerospora sorghi, is an economically important disease of maize. Downy mildew dm is a major disease of maize that causes signi. When combined with seed treatment, one foliar application of metalaxyl 225 ppm on the 30th day after. Plant health australia contingency plan downy mildew of maize and downy mildew of sorghum page 5 1 purpose of this contingency plan this contingency plan provides background information on the pest biology and available control. Incidence and geographical distribution of downy mildew on. In origin, the downy mildews are old world diseases that now are very damaging and prevalent on the new world crop maize shaw, 1975. Control of sorghum downy mildew peronosclerospora sorghi. Managing downy mildew in organic and conventional vine crops d owny mildew can be a serious disease on any. Plants grown from seeds treated with metalaxyl, or any mixture containing metalaxyl, remained free from the disease and had significantly higher grain yield than plants grown from seeds treated with thirambased fungicides or from untreated seeds. Hyo chul kim 1, kyunghee kim 1, kitae song 1, jae yoon kim 2 and byungmoo lee 1. Abstract incidence and geographical distribution of downy mildew peronosclerospora sorghi on maize zea mays were determined in a systematic survey of 181 maize fields in the major maize. Downy mildew in maize caused by peronosclerospora sorghi weston and uppal.
Pdf assessing genetic diversity in peronosclerospora sorghi. Hence, we employed two molecular marker systems, namely ssr simple sequence repeat and ardra amplified ribosomal dna restriction analysis markers, to study the. Some species that cause downy mildew can also be seed borne, although this is largely restricted to seed that is fresh and has high moisture content. Jan 02, 2019 downy mildew on maize tends to cause yellow streaking down the fibrous leaves. Of 16 chemicals tried, bleaching powder, rhizoctol, captan, plantvax and fennite inhibited sporangial germination in the labora tory test and had some effect when they were sprayed or used as a soil drench. Genes free fulltext identification and validation of. The downy mildew fungus, peronospora manshurica, is biotrophic, which means it can only grow in association with the soybean plant. Maize downy mildew 227 common name sugarcane downy mildew scientific name peronosclerospora sacchari distribution asia, africa nigeria only, oceania. Up to the present, nine species 2 genera of fungi are found to cause downy mildew on maize, each of which shows specific host range and geographical distribution. Downy mildew pathogens of maize among the various maize diseases, downy mildews are considered to be the major diseases. Field tests of 94 rils were conducted over two growing seasons. Executive summary philippine downy mildew of maize pdm, caused by the oomycete peronosclerospora philippinensis and brown stripe downy mildew bsdm caused by sclerophthora rayssiae var. Downy mildew dm, caused by several species of peronosclerospora and scleropthora, is a major maize zea mays l. White, gray, bluish, or violet downy patches of mildew form mostly on the undersides of leaves in damp weather.
Choose hybrid varieties with known resistance to maize downy mildew. Sweet corn is the taste of summer, but if you grow it in your garden, you could lose your crop to pests or disease. In 1959 it has been found in nasice croatia for the first time. Response to selection for downy mildew peronosclerospora sorghi and maize streak virus resistance in three quality protein maize populations in mozambique by david mariote bsc. These downy masses are most often noticed after rain or heavy dew and disappear soon after sunny weather resumes. Identity of a downy mildew in maize in nigerian guinea savanna.
Brown stripe downy mildew is not a systemic disease, and the pathogen will only be present in infected leaves. Bonde abstract the downy mildews of maize, sorghum and pearl millet are among the most destructive diseases in. The different strains of downy mildew can be very host specific, or it can infect many members of the daisy family, including this rudbeckia. Downy mildew causes a variety of symptoms depending on cucurbit type.
Zinc defficient soils are known to predispose the maize crop to the downy mildew infection 28. Shaw, was significantly controlled by foliar spray of phosphonic acid 20% and its formulations like aliette 0. Expression profiles of candidate genes for downy mildew resistance determined using quantitative rtpcr. Uppal shaw, is an economically important disease on maize zea mays l. Metalaxyl apron 35sd, used as a seed treatment, was highly effective in controlling sorghum downy mildew of maize induced by peronosclerospora sorghi. Using 10 to 60dayold maize plants in artificial inoculation tests it has been determined that infec tivity was reduced with the increase in the age of the host plants. Downy mildew in maize is caused by peronosclerospora spp. Assessment of loss in yield due to sorghum downy mildew peronosclerospora sorghi of maize in nigerian guinea savanna.
Efficacy of three systemic fungicides against downy mildew peronosclerospora maydis rac. Identifying genomic regions qtls, contributing to sdm resistance will aid in a markerassisted resistant breeding pr. Downy mildews exclusively belong to peronosporaceae. Amusa and others published control of downy mildew disease of maize in forest agroecologies of.
Maize in the us is susceptible to other downy mildew diseases, including sorghum downy mildew, caused by peronosclerospora sorghi, and crazy top, caused by sclerophthora macrospora. We conducted a genomewide association study for sorghum downy mildew sdm. In indonesia, downy mildew at first only occurs in some maize production areas, but along with the spread of maize, downy mildew has spread in several provinces. Epidemiology of downy mildew diseases of maize, sorghum and pearl millet based on a paper presented at the international conference on the graminaceous downy mildew diseases 28 november3 december 1979, bellagio, italy bonde, 1980b. Maize zea mays, oats, sugarcane, wild sugarcane, sorghum symptoms. Epidemiology of downy mildew diseases of maize, sorghum and pearl millet. In commercial agriculture, they are a particular problem for growers of crucifers, grapes and vegetables that grow on vines. Downy mildew is one of the most impor tant diseases of maize, sugarcane, and sor ghum in tropical and subtropical countries. Water that sits on the leaves of the plant gives the downy mildew a way to infect. Pdf unraveling the genetic diversity of maize downy. Bonde abstract the downy mildews of maize, sorghum and pearl millet are among the most destructive diseases in the tropics and. Geographical distribution of peronosclerospora spp. The expression intensity was calculated using the 2ct method livak and schmittgen, 2001, with b73 healthy as the control. Philippine downy mildew of maize pdm, caused by the oomycete peronosclerospora.
Downy mildew on sweet corn is a fungal infection that can stunt plants and reduce or destroy the harvest. The pathogens causing the diseases are peronosclerospora sorghi, p. Philippine downy mildew of maize perenosclerospora philippensis and. Most of maize varieties grown in nigeria are highly susceptible to downy mildew disease. Downy mildew plasmopara viticola affects many plants and appears as yellow to white patches on the upper surfaces of older leaves. The best control of downy mildew is to make sure that your plants do not get it in the first place. Downy mildew was observed in the forest and guinea savanna ecologies, but no disease was detected in other ecologies. Quantitative trait loci qtls of maize involved in mediating resistance to peronosclerospora sorghi, the causative agent of sorghum downy mildew sdm, were detected in a population of recombinant inbred lines rils derived from the zea mays l. Shaw, was significantly controlled by foliar spray of phosphonic acid. Qtl mapping for sorghum downy mildew disease resistance in. It depends on the type of downy mildew, and there are a lot. Sep 14, 2018 some species that cause downy mildew can also be seed borne, although this is largely restricted to seed that is fresh and has high moisture content. Varying effectiveness of metalaxyl fungicides and disease incidences caused by downy mildew to maize in several places in indonesia led to the speculation that genetic variation of peronosclerospora species in indonesia exists. Downy mildew is a common disease of soybean that occurs wherever soybean is grown.
Controlling downy mildew of maize caused by peronosclerospora. Because of this very close relationship with the soybean. Bp68w diseases of landscape plants purdue extension. Philippine downy mildew of maize pdm, caused by the oomycete peronosclerospora philippinensis and brown stripe downy mildew bsdm. Total rna from leaves from heathy or downy mildewinfected 6wkold maize plants was used to synthesize cdna. The causal pathogens, also called dms, are oomycetes not true fungi and are obligate parasites of higher plants. Epidemiology of downy mildew diseases of maize, sorghum and. Downy mildew disease, caused by peronosclerospora sorghi, is one of the most serious diseases of maize. At the onset of the growing season, at soil temperatures above 20c, oospores in the soil germinate in response to root exudates from susceptible maize seedlings. Field tests of 94 rils were conducted over two growing seasons using artificial.
Because downy mildew needs water to survive, the very best thing you can do to prevent downy mildew is to water your plants from below. Downy mildew on maize tends to cause yellow streaking down the fibrous leaves. Downy mildew, disease of plants, especially in cool humid regions, caused by several funguslike organisms of the phylum oomycota. Chlorotic stripes or overall yellowing on the first true and successive leaves. Globally, downy mildews are among the important foliar diseases of maize that cause significant yield losses. The genetics of resistance was reported to be polygenic. Sao paulo brazil a thesis submitted in fulfilment of the requirements for the degree of doctor of philosophy in. Pdf in 1999 a pronounced infection of maize with fungus sclerophthora macrospora occurred in slovenia, especially in its northeastern and.
Managing downy mildew in organic and conventional vine. Conferring resistance to downy mildew in maize zea mays l. Threat specific contingency plan plant health australia. Sweet corn downy mildew control managing downy mildew on. Pdf qtl mapping for sorghum downy mildew disease resistance. In contrast, symptoms in csivprnai r5 plants were greatly reduced, and r3 and r2 lines only showed mild symptoms fig 5a, red star in r5. Csivp functions in vasculature development and downy mildew. Of these, seven are caused by peronoslerospora species, two by sclerospora and one by euclerospora. Knowing how to prevent downy mildew in corn and how to control an infection if you see it in your garden is important. Nov, 2008 epidemiology of downy mildew diseases of maize, sorghum and pearl millet based on a paper presented at the international conference on the graminaceous downy mildew diseases 28 november3 december 1979, bellagio, italy bonde, 1980b.
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