Characterization of Strawberry Host Plant Resistance to Powdery Mildew caused by Podosphaera aphanis

2021 ◽  
Author(s):  
Michael Palmer ◽  
Gerald Holmes
Keyword(s):  
Powdery Mildew ◽  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Disease Incidence ◽  
Strawberry Cultivar ◽  
Plant Disease Management ◽  
Relative Differences ◽  
Moderately Resistant

Host plant resistance is an essential tool in plant disease management worldwide. Evaluations of strawberry cultivar resistance to powdery mildew were done previously in California, but many new cultivars have been released since the last evaluation in 1996 and merit evaluation for today’s growers. Two studies were conducted over the winter and summer of 2020, evaluating ten commonly grown cultivars. Powdery mildew-free plants were established in 3 L pots under high plastic tunnels and after three weeks (four- to five-leaf stage) moved into a powdery mildew-infested greenhouse. Disease incidence and severity ratings were taken weekly beginning at the first sign of disease. Ratings taken at 40 (winter) and 41 (summer) days after transfer to the greenhouse were used to make comparisons among cultivars. Significant differences were found in foliar disease severity among cultivars, but none were totally free of disease. Moderately resistant cultivars were ‘San Andreas’ and ‘Sweet Ann’. Highly susceptible cultivars were ‘BG 3.324’ and ‘Royal Royce’. Two field evaluations of the ten cultivars confirmed the observed relative differences in host resistance under field conditions. This information is valuable to California strawberry growers who select cultivars based in part on their susceptibility to economically important diseases such as powdery mildew.

Evaluation of Aegilops tauschii (Coss.) germplasm for Karnal bunt resistance in a screen house with simulated environmental conditions

2008 ◽  
Vol 6 (02) ◽  
pp. 79-84 ◽  
Author(s):  
Parveen Chhuneja ◽  
Satinder Kaur ◽  
Kuldeep Singh ◽  
H. S. Dhaliwal
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Environmental Conditions ◽  
Host Plant Resistance ◽  
Aegilops Tauschii ◽  
Karnal Bunt ◽  
Tilletia Indica ◽  
D Genome ◽  
Moderately Resistant ◽  
Screen House

Karnal bunt (KB) of wheat, caused byTilletia indica(Mitra) Mundkur, adversely affects international wheat trading and the movement of germplasm between countries due to quarantine restrictions. Breeding for host plant resistance requires the identification of KB resistance sources. Accessions of the D genome progenitor of bread wheat,Aegilops tauschii, were screened in a specially designed screen-house, where the optimum environmental conditions conducive for KB development were simulated by controlling temperature, humidity, fogging and shading. The 183 accessions were subjected to artificial inoculation with a mixture of nine KB isolates, and seven proved highly resistant and four moderately resistant over three rounds of screening over 3 years.

Management of Dry Root Rot in Chickpea (Cicer arietinum L.) Caused By Macrophomina phaseolina by Utilizing Host Plant Resistance, Fungicides and Bioagents

2020 ◽  
Author(s):  
H. Manjunatha ◽  
M. Saifulla
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Root Rot ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Resistant Varieties ◽  
Paper Technique ◽  
Blotter Paper ◽  
Cent Disease

Background: For the management of soil borne disease like dry root rot of chickpea caused by Macrophomina phaseolina, by using fungicides alone is not feasible due to environmental and health hazards. Hence integrated management of the disease by using resistant varieties, fungicides and bio-control agents is the best alternative. So the present study was aimed to identify resistant varieties, best fungicide and bioagent for management of dry root rot in chickpea. Methods: Two hundred and twelve genotypes were screened using blotter paper technique for identifying resistant genotypes for dry root rot. The experiment on management of dry root rot was conducted during Kharif and Rabi of 2013-14 using a susceptible chickpea variety JG-11 with 14 treatments including control with 3 replications. Result: Of two hundred and twelve chickpea genotypes screened for host plant resistance against Macrophomina phaseolina by blotter paper technique only one genotype ie. PBG-5 showed moderately resistant reaction. Among fourteen treatments including fungicides and bioagents imposed for the management of dry root rot, seed treatment with tebuconazole @ 2 g/kg recorded lowest per cent disease incidence of 9.43, with a highest yield of 722.81 kg/ha compared to untreated control which recorded the highest per cent disease incidence (40.10) with a lowest mean yield of 362.02 kg/ha.

scholarly journals Screening of sesame genotypes against powdery mildew disease caused by Erysiphe cichorecearum

2020 ◽  
Vol 13 (2) ◽  
pp. 175-179
Author(s):  
S.D. Jagtap ◽  
B.C. Game ◽  
P.E. More
Keyword(s):  
Powdery Mildew ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Combining Ability ◽  
Yield Losses ◽  
Night Temperature ◽  
Genetic Character ◽  
Powdery Mildew Disease ◽  
Sesame Genotypes ◽  
Moderately Resistant

Powdery mildew disease of sesame occurs on epidemic scale in areas of high rainfall and humidity coupled with low night temperature causing considerable yield losses. Use of host plant resistance is the practical approach to manage this disease, but proper resistance sources with combining ability for the trait are unknown. Hence, an experiment was conducted to determine resistance in sesame genotypes against powdery mildew disease. Among the twenty four genotypes screened, none was found resistant while, nine genotypes exhibited moderately resistant to tolerant reaction and 15 genotypes exhibited susceptible reaction. Apparent rate of infection value varied and at times they did not remain consistent for given genotype and also did not show a particular trend which is attributed to genetic character of the genotype. The AUDPC values differed considerably for different genotypes. The values of AUDPC and apparent rate of infection of susceptible varieties were high as compared to moderately susceptible varieties. Genotype ‘JLS-302-11’ and ‘JLT-7’ having minimum AUDPC and apparent rate of infection value showed lowest intensity of powdery mildew while, genotype ‘JLT-408’ having maximum AUDPC and apparent rate of infection value showed highest intensity of powdery mildew.

scholarly journals Effects of Host Plant Resistance and Fungicides on Severity of Cucumber Downy Mildew

HortScience ◽  
2013 ◽  
Vol 48 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Adam D. Call ◽  
Todd C. Wehner ◽  
Gerald J. Holmes ◽  
Peter S. Ojiambo
Keyword(s):  
Host Plant ◽  
Downy Mildew ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Maximum Yield ◽  
Plant Size ◽  
High Yield ◽  
High Yields ◽  
A Minor ◽  
Moderately Resistant

Cucurbit downy mildew caused by the oomycete Pseudoperonospora cubensis (Berk. And Curt) Rostov is a major disease of cucumber (Cucumis sativus L.) (Palti and Cohen, 1980) globally. Chemical control of downy mildew is necessary to achieve high yields in the absence of adequate host plant resistance. Most of the currently grown cultivars have some resistance to downy mildew. Before the resurgence of the disease in 2004, host plant resistance was sufficient to control the disease without fungicide use, and downy mildew was only a minor problem on cucumber. There are currently no cultivars that show resistance at a level equal to that observed before 2004. However, differences in resistance exist among cultivars, ranging from moderately resistant to highly susceptible. In this study, we evaluated the disease severity and yield of four cucumber cultivars that differed in disease resistance and were treated with fungicide programs representing a range of efficacy levels. The experiment was a split plot design with six replications and four years. Disease was evaluated as chlorosis, necrosis, and reduction in plant size on a 0 to 9 scale. Cultigen had a large effect in all four years. Fungicide has a smaller effect on resistance component traits and a larger effect on yield traits. The effects of cultivar resistance and fungicides appear to be additive until a threshold where maximum yield is reached. Highly resistant cultigens such as PI 197088 required only the least effective fungicides to achieve highest yields, whereas moderately resistant cultigens required a more effective fungicide to reach a similar level of yield. Susceptible cultigens did not achieve high yield even with the most effective fungicide treatments. It is likely that, even as highly resistant cultivars are released, growers will need to continue a minimal fungicide program to achieve maximum yield.

scholarly journals Improved host-plant resistance to Phytophthora rot and powdery mildew in soybean (Glycine max (L.) Merr.)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jegadeesan Ramalingam ◽  
Ganesh Alagarasan ◽  
Palanisamy Savitha ◽  
Kelsey Lydia ◽  
Govindan Pothiraj ◽  
...  
Keyword(s):  
Glycine Max ◽  
Powdery Mildew ◽  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Glycine Max L ◽  
Phytophthora Rot

scholarly journals Bio-control of Stem Rot in Jerusalem Artichoke (Helianthus tuberosus L.) in Field Conditions

2021 ◽  
Vol 37 (5) ◽  
pp. 428-436
Author(s):  
Chutsuda Junsopa ◽  
Weerasak Saksirirat ◽  
Suwita Saepaisan ◽  
Patcharin Songsri ◽  
Thawan Kesmala ◽  
...  
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Control Method ◽  
Disease Incidence ◽  
Jerusalem Artichoke ◽  
Field Conditions ◽  
Stem Rot ◽  
Effective Control ◽  
The Impact

Stem rot is a serious disease in Jerusalem artichoke (JA). To reduce the impact of this disease on yield and quality farmers often use fungicides, but this control method can be expensive and leave chemical residues. The objective of this study was to evaluate the efficacy of two biological control agents, Trichoderma harzianum T9 and Bacillus firmus BSR032 for control of Sclerotium rolfsii under field conditions. Four accessions of JA (HEL246, HEL65, JA47, and JA12) were treated or notreated with T. harzianum T9 and B. firmus BSR032 in a 4 × 2 × 2 factorial experiment in two fields (environments), one unfertilized and one fertilized. Plants were inoculated with S. rolfsii and disease was evaluated at 3-day intervals for 46 days. T. harzianum T9 and B. firmus BSR032 reduced disease incidence by 48% and 49%, respectively, whereas T. harzianum T9 + B. firmus BSR032 reduced disease incidence by 37%. The efficacy of T. harzianum T9 and B. firmus BSR032 for control of S. rolfsii was dependent on environments and genotypes. The expression of host plant resistance also depended on the environment. However, HEL246 showed consistently low disease incidence and severity index in both environments (fertilized and unfertilized). Individually, T. harzianum T9, B. firmus BSR032, or host plant resistance control stem rot caused by S. rolfsii in JA. However, no combination of these treatments provided more effective control than each alone.

scholarly journals Characterization of host plant resistance to zebra chip disease from species-derived potato genotypes and the identification of new sources of zebra chip resistance

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183283 ◽  
Author(s):  
Mahnaz Rashidi ◽  
Richard G. Novy ◽  
Christopher M. Wallis ◽  
Arash Rashed
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Zebra Chip ◽  
Zebra Chip Disease

scholarly journals Morphological and Chemical Factors Related to Western Flower Thrips Resistance in the Ornamental Gladiolus

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1384
Author(s):  
Dinar S. C. Wahyuni ◽  
Young Hae Choi ◽  
Kirsten A. Leiss ◽  
Peter G. L. Klinkhamer
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Resistance Breeding ◽  
Breeding Programs ◽  
Triterpenoid Saponins ◽  
Flower Thrips ◽  
Highly Correlated

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the 1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.

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