scholarly journals Molecular Strategies to Enhance the Genetic Resistance of Grapevines to Powdery Mildew

2015 ◽  
pp. 317-344
2018 ◽  
Vol 10 (4) ◽  
pp. 279-284
Author(s):  
Zh. Ivanova ◽  
K. Vasileva ◽  
N. Velkov ◽  
S. Grozeva

Abstract. Powdery mildew, caused by Podosphaera xanthii and Golovinomyces cichoracearum, is an economically important disease in melon worldwide. Genetic resistance is one of the most suitable strategies to control powdery mildew. During the last few years several races of the pathogens have been reported. The need to develop resistant varieties is a challenge for each breeding program. Leaf disc assay was used in phytopathology and breeding programs as a rapid and reliable method for evaluation of disease resistance in a large number of plant materials. The purpose of this study was to establish species and races of powdery mildew in Plovdiv region, South Central Bulgaria; to develop a suitable system of pathogen isolation and cultivation; to determine the resistance levels in different melon genotypes available in Maritsa Vegetable Crops Research Institute (MVCRI) - Plovdiv collection by the leaf disc assay. Fifty-three melon genotypes, including lines, varieties, hybrids and ten differential lines were tested. The data showed that causal agent of powdery mildew was race 1 of P. xanthii in Plovdiv region. Our experimental results indicated that for the long-term storage of powdery mildew it is preferable to keep a whole plant under in vitro conditions. This allows the preservation of powdery mildew for two months before transferring on a new tissue. Thirty-four of the tested melon genotypes reacted as immune or resistant and nineteen as susceptible. Resistant melon genotypes are a suitable source in initiating a new breeding program aimed to increase resistance to powdery mildew.


Author(s):  
Reginah Pheirim ◽  
Noren Singh Konjengbam ◽  
Mayurakshee Mahanta

Powdery mildew is caused by an obligate parasite Erysiphe pisi and considered as one of the most important constraints causing yield reductions in pea. Development and utilization of genetic resistance is acknowledged as the most effective, economic and environmental friendly method of control. Therefore, development of cultivars with improved resistance to biotic stresses is a primary goal of plant breeding programs throughout the world. Three monogenic sources er1, er2 and Er3 have been described to govern the powdery mildew disease resistance. Several markers have been reported linked to resistant genes at varying distances in different mapping populations. Genetic markers linked to the disease resistance gene make the breeding process more efficient for the use of Marker Assisted Selection (MAS) strategy to aid in obtaining a complete powdery mildew resistance in pea.


Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 971 ◽  
Author(s):  
Antonín Dreiseitl

Powdery mildew caused by the airborne ascomycete fungus Blumeria graminis f. sp. hordei (Bgh) is one of most common diseases of barley (Hordeum vulgare). This, as with many other plant pathogens, can be efficiently controlled by inexpensive and environmentally-friendly genetic resistance. General requirements for resistance to the pathogens are effectiveness and durability. Resistance of barley to Bgh has been studied intensively, and this review describes recent research and summarizes the specific resistance genes found in barley varieties since the last conspectus. Bgh is extraordinarily adaptable, and some commonly recommended strategies for using genetic resistance, including pyramiding of specific genes, may not be effective because they can only contribute to a limited extent to obtain sufficient resistance durability of widely-grown cultivars. In spring barley, breeding the nonspecific mlo gene is a valuable source of durable resistance. Pyramiding of nonspecific quantitative resistance genes or using introgressions derived from bulbous barley (Hordeum bulbosum) are promising ways for breeding future winter barley cultivars. The utilization of a wide spectrum of nonhost resistances can also be adopted once practical methods have been developed.


Author(s):  
S. Priyanka ◽  
S. Rangaiah ◽  
R. Pavan

An effective and durable genetic resistance in black gram genotypes against powdery mildew provides a cost effective and reliable strategy to reduce the yield losses and save quality of the harvest. The identification of potential resistant source(s) is the most crucial step in disease resistance breeding. In the present study, out of 116 genotypes screened, genotype LBG-645 recorded lowest per cent disease severity of 0.77 and was found to be highly resistant to powdery mildew under green house condition. Under in vitro condition also, LBG-645 which was found to be highly resistant with 3.33×103 conidia colony, 0.94 per cent of leaf area covered by powdery mildew and 1.00 colony per leaflet was recorded. Hence, resistant genotype LBG-645 must be used in further breeding programme for the development of resistant varieties of black gram against powdery mildew.


2021 ◽  
Vol 34 ◽  
pp. 02001
Author(s):  
Elena Ilnitskaya ◽  
Marina Makarkina ◽  
Valeriy Petrov

Downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator) are the most common and economically significant fungal diseases in vineyards. The task of this work is to study the genotypes of new promising hybrid forms of table grapes for the presence of resistance genes to downy mildew (Rpv10 and Rpv3) and powdery mildew (Ren9) using DNA-markers. The study was carried out on table grape hybrids under the working names Agat dubovskiy, Akelo, Arabella, Artek, Dubovskiy rozovyi, Gamlet, Ispolin, Kishmish dubovskiy, Kurazh, Pestryi, Valensiya and registered variety Liviya. The studied genes were analyzed using markers UDV305 and UDV737 (Rpv3), GF09-46 (Rpv10), CenGen6 (Ren9). The following cultivars were used as reference genotypes: Saperavi severnyi (carries Rpv10 gene) and Regent (Rpv3 and Ren9). It was established that Rpv3 gene is carried by hybrids Kishmish dubovskiy, Agat dubovskiy, Kurazh, Valensiya, Akelo, Gamlet, Dubovskiy rozovyi, Pestryi. Ren9 gene was found in Artek, Agat dubovskiy, Kurazh, Ispolin, Valensiya, Arabella, Gamlet, Dubovskiy rozovyi, Pestryi. The Rpv10 gene was not detected in any of the analyzed grapevine samples. genotypes Agat dubovskiy, Kurazh, Gamlet, Dubovskiy rozovyi, Pestryi, Valensiya carry Rpv3 and Ren9 genes simultaneously. These grapevines have an elegant bunch and large berries that are attractive to consumers.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 888a-888 ◽  
Author(s):  
James D. McCreight ◽  
Michael D. Coffey ◽  
Thomas A. Turini ◽  
Michael E. Matheron

Races 1 and 2 of Podosphaera xanthii (syn. Sphaerotheca fuliginea) were defined in Imperial Valley, Calif. 1938 when P. xanthii overcame genetic resistance in `PMR 45'. Race 3 was first observed in the U.S. in 1976 in Texas; 15 additional races of P. xanthii have been reported in the literature since 1996. Races 1 and 2 have been common in Arizona and California based upon the effectiveness of the powdery mildew resistance genes in commercially available melon cultivars grown in these states. Field data from 11 commonly used melon P. xanthii race differentials in 2001 and 2002 indicated the presence of race 1 in the Imperial Valley and San Joaquin Valley of California, and Yuma, Arizona. In spring 2003, the powdery mildew race situation changed. The first evidence was the occurrence of a severe and widespread infection of powdery mildew in a commercial cantaloupe field. The 11 powdery mildew race differentials were susceptible to powdery mildew in a nearby replicated field test. PI 313970, a melon from India, was resistant to this apparent new race of powdery mildew.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 404A-404
Author(s):  
James W. Olmstead ◽  
Gregory A. Lang ◽  
Gary G. Grove

Most sweet cherry (Prunus avium L.) cultivars grown commercially in the Pacific Northwest U.S. are susceptible to powdery mildew caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. The disease is prevalent in the irrigated arid region east of the Cascade Mountains in Washington State. Little is known about genetic resistance to powdery mildew in sweet cherry, although a selection (`PMR-1') was identified at the Washington State Unive. Irrigated Agriculture Research and Extension Center that exhibits apparent foliar immunity to the disease. The objective of this research was to characterize the inheritance of powdery mildew resistance from `PMR-1'. Reciprocal crosses between `PMR-1' and three high-quality, widely-grown susceptible cultivars (`Bing', `Rainier', and ëVaní) were made to generate segregating progenies for determining the mode of inheritance of `PMR-1' resistance. Progenies were screened for susceptibility to powdery mildew colonization using a laboratory leaf disk assay. Assay results were verified by natural spread of powdery mildew among the progeny seedlings in a greenhouse and later by placement among infected trees in a cherry orchard. Progenies from these crosses were not significantly different (P > 0.05) when tested for a 1:1 resistant to susceptible segregation ratio, indicating that `PMR-1' resistance is conferred by a single gene, which we propose to designate as PMR-1.


2011 ◽  
Vol 48 (No. 5) ◽  
pp. 217-223 ◽  
Author(s):  
J.H. Czembor ◽  
H.J. Czembor

Powdery mildew on barley (Hordeum vulgare L.) caused by the pathogen Blumeria graminis f.sp. hordei occurs worldwide and can result in severe yield loss. Because agronomical methods to control the disease are not completely effective, cultivars with genetic resistance are needed. Therefore, there is a need to describe new sources of genes that confer resistance to barley powdery mildew. This study was conducted to determine the genetic basis of resistance to powdery mildew in three selections 995-1-1, 995-1-2, 995-1-3 from barley landrace 995 (ICB 112840) collected in Al Aziziyah district, Tripolitania, Libya. Landrace originated from InternationalCenter for Agricultural Research in the Dry Areas – ICARDA, Aleppo, Syria. To determine the number of genes, the types of genes action and the gene loci in tested lines two types of crosses were made: (1) the lines were crossed to the susceptible cultivar Pallas, (2) the lines were crossed with Pallas isoline P22 carrying gene mlo5. The parents and progeny F2 were evaluated with isolate R303.1 for the powdery mildew resistance. Based on segregation ratios we found that resistance in these three selections was determined by a single recessive gene allelic to the Mlo locus occurring in Pallas isoline P22. In addition tested lines showed resistance reaction type 0(4) characteristic only for genes mlo. The value of new identified sources of highly effective powdery mildew resistance to breeding programs and barley production is discussed.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Antonín Dreiseitl

Abstract Powdery mildew, a common cereal disease caused by the fungus Blumeria graminis, is a major limiting factor of barley production and genetic resistance is the most appropriate protection against it. To aid the breeding of new cultivars and their marketing, resistance genes can be postulated in homogeneous accessions. Although hybrid cultivars (F1) should be homogeneous, they are often not genetically uniform, especially if more than two genotypes are involved in their seed production or due to undesirable self-pollination, out-crossing and mechanical admixtures. To overcome these problems the accepted method of postulating specific resistance genes based on comparing response type arrays (RTAs) of genetically homogeneous cultivars with RTAs of standard genotypes was substituted by analysing the frequency of response types to clusters of pathogen isolates in segregating F2 generations. This method combines a genetic and phytopathological approach for identifying resistance genes. To assess its applicability six hybrid cultivars were screened and from three to seven with a total of 14 resistance genes were found. Two genes were newly located at the Mla locus and their heritability determined. In addition, three unknown dominant genes were detected. This novel, comprehensive and efficient method to identifying resistance genes in hybrid cultivars can also be applied in other cereals and crops.


2020 ◽  

This specially curated collection features four reviews of current and key research on fusarium in cereal crops. The first chapter describes how progress can be built over current agricultural practices in integrated pest management plans. It also addresses the disease cycle of Fusarium head blight, host–pathogen interactions, genetic resistance, the role of mycotoxins, as well as the impact of the disease on yields and loss of crop quality. The second chapter reviews current research on the main fungal diseases affecting barley, as well as what we know about the mechanisms of barley genetic resistance to fungal pathogens. It features detailed discussions on biotrophic foliar diseases such as stem rust and powdery mildew and necrotrophic diseases such as spot blotch and Fusarium head blight. The third chapter reviews control measures for Fusarium head blight, wheat blast and powdery mildew, including the development of resistant cultivars. The final chapter considers the current status of global wheat production, the impact of crop loss on food security and the emergence of the current regulatory environment surrounding pesticides. It also features discussions on the current status of the global fungicide market.


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