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.

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.

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

Variability Studies in Melon (Cucumis melo.L) F2 Population of Kashi Madhu x COHB38 for Powdery Mildew Resistance

2019 ◽  
Vol 7 (4) ◽  
pp. 407-413
Author(s):  
K.R. Kavya ◽  
Manchali Shivapriya
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Continuous Distribution ◽  
F2 Population ◽  
Progress Curve ◽  
Powdery Mildew Disease ◽  
Percent Disease Index ◽  
Natural Field Condition ◽  
Moderately Resistant ◽  
Segregating Population

The present investigation was carried at College of Horticulture, Bengaluru. Evaluation of melon F2 population (Kashi Madhu X COHB38) was conducted during rabi 2016 for resistance to powdery mildew disease under natural field condition. Percent Disease Index (PDI) and AUDPC (Area Under Disease Progress Curve) value was calculated to assess the reaction of F2 (Kashi Madhu X COHB38) segregating population of melon along with the parents (COHB38 and Kashi Madhu) and F1. Based on PDI for powdery mildew disease, 152 F2 plants were classified into different categories. Twenty five F2s were resistant (0-25% PDI), 27 were moderately resistant (25.1-40% PDI), 88 were susceptible (40.1-60% PDI) and 12 F2s were highly susceptible (>60% PDI). Among 152 F2 plants,    F2 -34 was found to be highly resistant with zero PDI and zero AUDPC value (no disease) followed by F2- 46 and 92 with PDI of 13.89 % and 16.11 % and 46.94 and 55.00 AUDPC value, respectively. The PDI of the disease showed a continuous distribution from highly resistant to highly susceptible phenotypes, without showing any typical segregation pattern. Int. J. Appl. Sci. Biotechnol. Vol 7(4): 407-413

scholarly journals MORTALITY AND DEVELOPMENT OF PEAR PSYLLA NYMPHS ON EAST EUROPEAN PEAR GERMPLASM

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1131d-1131 ◽  
Author(s):  
Richard L. Bell ◽  
L. Claire Stuart
Keyword(s):  
Plant Resistance ◽  
Host Plant Resistance ◽  
East Asian ◽  
Asian Origin ◽  
European Origin ◽  
European Pear ◽  
East European ◽  
Pear Psylla ◽  
Susceptible Control ◽  
Moderately Resistant

Four genotypes of pear (Pyrus spp.) of East European origin, a susceptible control, `Bartlett' (P. communis L.), and a moderately resistant control, NY 10352 (P. ussuriensis Maxim. × P. communis B C1 hybrid), were artificially infested with pear psylla (Cacopsyll a pyricol a Foerster) nymphs in the laboratory. Ten neonate first instars were placed on each of the two youngest leaves of four small trees per genotype. On PI 506381 and PI 506382, wild seedlings of P. nivalis Jacq., all nymphs died within 5 days. Mortality and development of nymphs on PI 502173, a wild P. communis seedling, was similar to that observed on `Bartlett', with 43% and 45% of the nymphs surviving to adulthood, respectively. On `Karamanlika' (PI 502165) and NY 10352, 15% of the nymphs developed into adults. Increased mortality and delayed development of nymphs was associated with feeding inhibition. The mode of host plant resistance to pear psylla nymphs in these accessions of East European pear is, therefore, similar to that previously characterized for NY 10352, in which the resistance is derived from germplasm of East Asian origin.

Incidence of powdery mildew on cucurbit plants in Katsina, Nigeria

2019 ◽  
pp. 05-09
Keyword(s):  
Powdery Mildew ◽  
Low Cost ◽  
Frequency Of Occurrence ◽  
Sphaerotheca Fuliginea ◽  
Causal Organism ◽  
Powdery Mildews ◽  
Powdery Mildew Disease ◽  
Important Disease

The presence study deals with powdery mildews in various cucurbits in Katsina city (Barhim Estate, Kofar Durbi, Kofar Sauri, Kofar Marusa and Low Cost), Nigeria. The finding shows that the areas infested with powdery mildew is one of the important disease of cucurbits. The Sphaerotheca fuliginea was identified to be the causal organism present on all observed cucurbits in the study. Highest frequency of disease was found in Kofar Sauri(79%) fallowed by Kofar Marusa (68%), Kofar Durbi (66%), Barhim Estate (65%) and the lowest frequency of occurrence of disease was found in Low Cost (55%).The intensity of the disease was moderate to severe in general but it was high in many fields, the area-wise variation was also noticed. On vegetables, the highest frequency of occurrence of powdery mildew disease was observed on L. cylindrica (76.4%) followed by C. moschata (60%), C. sativus (59.3%), C. vulgaris (53.9%) and lowest was found on C. melo (44.4%). The highest intensity of disease was found on C. moschata, followed by L. cylindrica, C. sativus, C. vulgaris and C. melo.

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