scholarly journals Environmentally Induced Variability in the Host Reaction of Barley to Net Blotch

1969 ◽  
Vol 22 (5) ◽  
pp. 1237 ◽  
Author(s):  
TN Khan ◽  
WJR Boyd
Keyword(s):  
Environmental Conditions ◽  
Susceptible Variety ◽  
Post Inoculation ◽  
Net Blotch ◽  
Host Reaction ◽  
Drechslera Teres ◽  
Resistant Varieties

The host reaction of two Ethiopian and four Manchurian resistant varieties, and one susceptible variety of barley to isolate 177 of Drechslera teres was studied under a range of environmental conditions. The effects were specific to the variety(ies) used, with the exception of the factor of post-inoculation temperature. High post-inoculation temperatures brought about the breakdown of resistance in all the varieties.

INHERITANCE OF RESISTANCE TO NET BLOTCH IN BARLEY. I. FACTORS AFFECTING THE PENETRANCE AND EXPRESSIVITY OF GENE(S) CONDITIONING HOST RESISTANCE

1969 ◽  
Vol 11 (3) ◽  
pp. 587-591 ◽  
Author(s):  
T. N. Khan
Keyword(s):  
Environmental Conditions ◽  
Net Blotch ◽  
Host Reaction ◽  
Susceptible Parent ◽  
Breeding Programs ◽  
Genetic Studies ◽  
Factors Affecting ◽  
Drechslera Teres ◽  
Resistant Varieties ◽  
High Level

Variability in the host-reaction of barley to infection by Drechslera teres was examined in the parents and progeny of selected crosses under different environmental conditions of testing.The Ethiopian variety C.I. 5791 exhibits a consistently high level of resistance under a range of environmental conditions, which is in contrast to the Manchurian variety C.I. 2330. The sensitivity of the genes for resistance possessed by these varieties to environmental modifications is considered to depend upon their respective genetic backgrounds. Furthermore, variability of host reaction in the progeny of these resistant varieties was shown to be influenced by the genetic background of the susceptible parent used.The implications of these findings in the conduct and interpretation of genetic studies and in backcross breeding programs is discussed.

scholarly journals Hormonal and metabolites responses in Fusarium wilt-susceptible and -resistant watermelon plants during plant-pathogen interactions

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Deepak M. Kasote ◽  
G. K. Jayaprakasha ◽  
Kevin Ong ◽  
Kevin M. Crosby ◽  
Bhimanagouda S. Patil
Keyword(s):  
Fusarium Wilt ◽  
Leaf Tissue ◽  
Defense Responses ◽  
Susceptible Variety ◽  
Post Inoculation ◽  
Resistant Varieties ◽  
Before And After ◽  
Amino Acid Profiles ◽  
Plant Pathogen Interactions ◽  
Indole 3 Acetic Acid

Abstract Background Fusarium oxysporum f. sp. niveum (FON) causes Fusarium wilt in watermelon. Several disease-resistant watermelon varieties have been developed to combat Fusarium wilt. However, the key metabolites that mount defense responses in these watermelon varieties are unknown. Herein, we analyzed hormones, melatonin, phenolic acids, and amino acid profiles in the leaf tissue of FON zero (0)-resistant (PI-296341, Calhoun Grey, and Charleston Grey) and -susceptible (Sugar Baby) watermelon varieties before and after infection. Results We found that jasmonic acid-isoleucine (JA-Ile) and methyl jasmonate (MeJA) were selectively accumulated in one or more studied resistant varieties upon infection. However, indole-3-acetic acid (IAA) was only observed in the FON 0 inoculated plants of all varieties on the 16th day of post-inoculation. The melatonin content of PI-296341 decreased upon infection. Conversely, melatonin was only detected in the FON 0 inoculated plants of Sugar Baby and Charleston Grey varieties. On the 16th day of post-inoculation, the lysine content in resistant varieties was significantly reduced, whereas it was found to be elevated in the susceptible variety. Conclusions Taken together, Me-JA, JA-Ile, melatonin, and lysine may have crucial roles in developing defense responses against the FON 0 pathogen, and IAA can be a biomarker of FON 0 infection in watermelon plants.

Host range and physiologic specialization in Rhynchosporium secalis

1974 ◽  
Vol 25 (1) ◽  
pp. 21 ◽  
Author(s):  
SM Ali ◽  
WJR Boyd
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Environmental Conditions ◽  
Host Specialization ◽  
Rhynchosporium Secalis ◽  
Host Reaction ◽  
Genetic Studies ◽  
Barley Cultivars ◽  
Adequate Sampling ◽  
Pathogenic Variability

The pathogenic variability of isolates of R. secalis collected in Western Australia has been examined on different host genera of the Gramineae and on selected barley cultivars. Depending on the host-isolate combination and the conditions of the test, evidence has been obtained of inter- and intra-isolate variability in both host reaction and isolate pathogenicity. This complicates definitive interpretation of the results, militates against identification of conventional 'races' of the pathogen and shows that R. secalis does not exhibit strict host specialization. Hosts which consistently express resistance or susceptibility under different environmental conditions, and isolates which express their pathogenic characteristics consistently, have been identified. The need for more precise genetic studies and adequate sampling of genetic diversity is emphasized.

SOURCES OF RESISTANCE IN BARLEY TO PYRENOPHORA TERES

1965 ◽  
Vol 45 (2) ◽  
pp. 189-193 ◽  
Author(s):  
K. W. Buchannon ◽  
W. C. McDonald
Keyword(s):  
North Dakota ◽  
Quality Characteristics ◽  
Seedling Stage ◽  
Malting Quality ◽  
Western Canada ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Sources Of Resistance ◽  
Highly Pathogenic ◽  
Resistant Varieties

The reaction to infection by Pyrenophora teres Drechs., the incitant of net blotch of barley, was determined for 6,174 varieties in the U.S.D.A. World Barley Collection. Forty varieties, seventeen of them from Ethiopia, were resistant in the seedling stage to a highly pathogenic strain of the fungus prevalent in Western Canada and to composites of isolates from Manitoba, Saskatchewan, Alberta, Ontario, North Dakota, California, and Mexico. They were also resistant in the field at three locations in Western Canada. Agronomic and malting quality characteristics for the resistant varieties were also recorded.

scholarly journals A metabolomics characterisation of natural variation in the resistance of cassava to whitefly

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Laura Perez-Fons ◽  
Adriana Bohorquez-Chaux ◽  
Maria L. Irigoyen ◽  
Danielle C. Garceau ◽  
Kris Morreel ◽  
...  
Keyword(s):  
Time Course ◽  
Management Strategies ◽  
Resistance Mechanism ◽  
Central Africa ◽  
Susceptible Variety ◽  
Induced Response ◽  
Genotypic Differences ◽  
Germplasm Collections ◽  
Resistant Varieties ◽  
Quantitative Changes

Abstract Background Cassava whitefly outbreaks were initially reported in East and Central Africa cassava (Manihot esculenta Crantz) growing regions in the 1990’s and have now spread to other geographical locations, becoming a global pest severely affecting farmers and smallholder income. Whiteflies impact plant yield via feeding and vectoring cassava mosaic and brown streak viruses, making roots unsuitable for food or trading. Deployment of virus resistant varieties has had little impact on whitefly populations and therefore development of whitefly resistant varieties is also necessary as part of integrated pest management strategies. Suitable sources of whitefly resistance exist in germplasm collections that require further characterization to facilitate and assist breeding programs. Results In the present work, a hierarchical metabolomics approach has been employed to investigate the underlying biochemical mechanisms associated with whitefly resistance by comparing two naturally occurring accessions of cassava, one susceptible and one resistant to whitefly. Quantitative differences between genotypes detected at pre-infestation stages were consistently observed at each time point throughout the course of the whitefly infestation. This prevalent differential feature suggests that inherent genotypic differences override the response induced by the presence of whitefly and that they are directly linked with the phenotype observed. The most significant quantitative changes relating to whitefly susceptibility were linked to the phenylpropanoid super-pathway and its linked sub-pathways: monolignol, flavonoid and lignan biosynthesis. These findings suggest that the lignification process in the susceptible variety is less active, as the susceptible accession deposits less lignin and accumulates monolignol intermediates and derivatives thereof, differences that are maintained during the time-course of the infestation. Conclusions Resistance mechanism associated to the cassava whitefly-resistant accession ECU72 is an antixenosis strategy based on reinforcement of cell walls. Both resistant and susceptible accessions respond differently to whitefly attack at biochemical level, but the inherent metabolic differences are directly linked to the resistance phenotype rather than an induced response in the plant.

scholarly journals Development of a single uredinium inoculation method for Puccinia kuehnii, the causal agent of sugarcane orange rust

2018 ◽  
Vol 44 (4) ◽  
pp. 311-316 ◽  
Author(s):  
Lis Natali Rodrigues Porto ◽  
Alfredo Seiiti Urashima
Keyword(s):  
Phenotypic Diversity ◽  
Susceptible Variety ◽  
Resistant Genotype ◽  
Puccinia Kuehnii ◽  
Inoculation Techniques ◽  
Resistant Varieties ◽  
Injured Area ◽  
Significant Difference ◽  
Ideal Method

ABSTRACT The use of resistant varieties is the ideal method to control rusts. Nevertheless, knowing the pathogen’s diversity is fundamental to the success of this measure. Diversity can be analyzed phenotypically and/or genotypically. For phenotypic diversity, the reaction of genotypes is assessed by means of inoculations of the pathogen generally obtained from several uredinia. One handicap of this technique is its impossibility to detect diversity among these uredinia, assuming that they are all homogenous. Therefore, the aim of the present study was to develop a single uredinium technique for Puccinia kuehnii to be used in studies of rust diversity in sugarcane. The comparison between the two inoculation methods was done by employing urediniospores from SP89-1115 on the varieties SP89-1115 (susceptible) and RB975201 (resistant). The adopted design was completely randomized with five and seven replicates, respectively, examining incubation, latency, disease score, and injured area at 14 and 21 days. The two inoculation techniques were significantly equal for the susceptible variety, considering all evaluated parameters. For the resistant genotype, a significant difference was identified in the injured area and such difference did not interfere in the classification of the reaction of the material since values were below 1%. The single uredinium technique developed in this study showed to be reliable since the genotypic profile of the inoculated fungus was similar to that of pathogens from the produced lesions.

Epidemiology and control of spot form of net blotch (Pyrenophora teres f. maculata) of barley: a review

2009 ◽  
Vol 60 (4) ◽  
pp. 303 ◽  
Author(s):  
Mark S. McLean ◽  
Barbara J. Howlett ◽  
Grant J. Hollaway
Keyword(s):  
Cost Effective ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Stubble Retention ◽  
Resistant Varieties ◽  
Cost Effective Method ◽  
Barley Germplasm ◽  
Grain Yield And Quality ◽  
The 1960S ◽  
And Control

Spot form of net blotch (SFNB), caused by the fungus Pyrenophora teres f. maculata, was first described in Denmark in the 1960s and is now a prevalent foliar disease of barley in many countries. This disease should be controlled as a separate disease-causing organism from the net form of net blotch (NFNB), which is caused by P. teres f. teres. The increase in prevalence of SFNB is primarily due to stubble retention and cultivation of susceptible varieties, which have resulted in increased inoculum. Infected barley stubble is the primary inoculum source for SFNB, producing both asexual spores (conidia) and sexual spores (ascospores) from pseudothecia. Spot form of net blotch causes significant losses in grain yield and quality in situations where inoculum is present, susceptible varieties are cultivated, and where the climate is cool and moist. Cultivation of resistant varieties is the most cost-effective method for control of SFNB and more than 12 different resistance sources have been identified in barley germplasm and wild barley relatives. The resistance loci of 11 of these have been mapped. Control of SFNB can also be achieved with application of foliar fungicides, crop rotation, and stubble destruction.

The control of bacterial blight in rain-grown cotton. II. Some effects of infection on growth and yield

1965 ◽  
Vol 65 (1) ◽  
pp. 29-40 ◽  
Author(s):  
M. H. Arnold
Keyword(s):  
Bacterial Blight ◽  
Susceptible Variety ◽  
Growth And Yield ◽  
Crop Loss ◽  
Seed Cotton ◽  
The Third ◽  
Seed Dressing ◽  
Resistant Varieties ◽  
Series Of Experiments ◽  
Moderately Resistant

Three series of experiments are described from which minimum estimates of crop loss caused by bacterial blight were obtained. In the first two, the estimates were derived from seed-dressing trials, and in the third, seed dressing was used in conjunction with resistant varieties.Losses amounted to as much as 354 ± 39 lb. seed cotton/acre for a susceptible variety but could be reduced both by seed dressing and by using resistant varieties. The effectiveness of resistance in moderately resistant varieties varied from one season to the next, an effect comparable with the genotype-environment interactions previously described for reactions to inoculation.

scholarly journals PENGARUH PENYAKIT KRUPUK TERHADAP HASIL DAN MUTU DELAPAN VARIETAS TEMBAKAU VIRGINIA

2020 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
GEMBONG DALMADIYO ◽  
MOCH. AMIR KARTAMIDJAJA
Keyword(s):  
Block Design ◽  
Susceptible Variety ◽  
Diseased Plant ◽  
Yield And Quality ◽  
Randomized Block Design ◽  
Resistant Varieties ◽  
Tobacco Seedlings ◽  
Grade Index ◽  
Leaf Curl Disease

<p><strong>The effect of tobacco curl disease on the yield and quality of eight Virginia tobacco varieties</strong></p><p>Tobacco leaf curl disease is one of the important diseases on Virginia tobacco which especially occurs in dry condition. The use of resistant varieties is one of the most effective way to control the disease. This experiment was lo evaluate the effect of tobacco curl disease on tobacco varieties (DB 101, Coker 319, Coker 176, Coker 48, Coker 86, and Coker 371 Gold) and two promising lines (T.45/T.65 and T.45/T.69). The experiment was conducted in Pekuwon, Sumberrejo, Bojonegoro from April to October 1997. The experiment was arranged in randomized block design with three replications. The tobacco seedlings wee transplanted in 0.9 m x 0.6 m spacing and 9.0 m x 9.0 m plot size. The fertilizer dosage applied are 300 kg ZA + 108 kg SP-36 + 156 kg ZK per ha The parameters observed including percentage of diseased plant, productive leaves, as well as the yield and quality of leaves. The esults showed that Coker 371 Gold variety showed the lowest disease percentage (6.89%), decrease in productive leaves was high (71.86%), Whereas the two promising lines, were T.45/T.6S and T.45/T.69 showed that the percentage of diseased plants wee not significantly different compared with DB 101, Coker 319, and Coker 48, but the decrease in productive leaves was lower. The yield of these promising lines were 10.12-10.30 kg/81 m!, grade indexes 86.04-87.27, and crop indexes are 88.31-88.63. Coker 176 was the most susceptible variety. The percentage of diseased plant, flue- cured yield, grade index, and crop index on Coker 176 wee 42.67%, 7.77 kg/81 m!, 86.09, and 66.89, respectively.</p>

scholarly journals The use of detached leaf inoculation for selecting Cercospora kikuchii resistance in soybean genotypes

2021 ◽  
Author(s):  
Takeshi Kashiwa ◽  
Miguel Angel Lavilla ◽  
Antonio Diaz Paleo ◽  
Antonio Juan Gerardo Ivancovich ◽  
Naoki Yamanaka
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Screening Method ◽  
Post Inoculation ◽  
Soybean Genotype ◽  
Resistant Varieties ◽  
Soybean Genotypes ◽  
Soybean Resistance ◽  
Soybean Leaves ◽  
Resistant Genotypes

Cercospora leaf blight (CLB) causes extensive losses in soybean production in worldwide, including major soybean producing countries such as Argentina. C. kikuchii, C. cf. sigesbeckiae, C. cf. flagellaris, and C. cf. nicotianae are identified as pathogen of CLB. Soybean resistance for CLB is still unknown. Also, chemical control for CLB is losing effectiveness by fungicide resistance of the pathogen, such as C. kikuchii. We urgently need to breed a CLB resistant cultivar. Unfortunately, efficient methods for the screening of a resistant soybean genotype have not yet been established. In this study, we designed new, high-throughput inoculation method for identifying resistance against one of the CLB pathogen, C. kikuchii. We used liquid-cultured mycelia of the pathogen C. kikuchii on detached soybean leaves. Lesions on soybean leaflets appeared nine days post inoculation by this method. We used this method to select four C. kikuchii resistant genotypes from 80 genotypes in the World Soybean Core Collection. High-throughput screening method developed in this study can contribute to the research about C. kikuchii resistance by facilitating identification of resistant varieties.

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