scholarly journals Inheritance of Phytophthora Root Rot and Foliar Blight Resistance in Pepper

1999 ◽  
Vol 124 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Stephanie J. Walker ◽  
Paul W. Bosland
Keyword(s):  
Root Rot ◽  
Phytophthora Capsici ◽  
Dominant Gene ◽  
Segregation Ratio ◽  
Stem Cutting ◽  
Blight Resistance ◽  
Phytophthora Root Rot ◽  
Resistant Parent ◽  
Foliar Blight ◽  
Foliar Resistance

The inheritance of resistance to Phytophthora capsici Leonian root rot and foliar blight was compared in two different Capsicum annuum L. var. annuum pod types. The seedling was screened for phytophthora root rot, while a genetically identical stem cutting was screened for phytophthora foliar blight to determine if the same gene(s) confer resistance to both disease syndromes. The susceptible parents were `Keystone Resistant Giant #3' (`Keystone'), a bell pepper type, and `Early Jalapeño', while `Criollo de Morelos-334' was the resistant parent. Resistance was observed in both F1 populations screened for phytophthora root and foliar infection indicating dominance for resistance. Reciprocal effects were not detected. To determine if the same gene(s) conferred root rot and foliar resistance, root rot screening results were matched to the corresponding foliar blight stem cutting reaction. The segregation of resistance in the F2 generations was dependent on the susceptible parent. In the F2 generation derived from `Early Jalapeño', root rot resistance and foliar blight resistance segregated in a 9:3:3:1 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. One independent, dominant gene was necessary for root rot resistance, and a different independent, dominant gene was needed for foliar blight resistance. In the F2 generation derived from `Keystone', root rot and foliar blight resistance segregated in a 7:2:2:5 (root resistant/foliar resistant: root resistant/foliar susceptible: root susceptible/foliar resistant: root susceptible/foliar susceptible) ratio. This segregation ratio is expected when one dominant gene is required for root resistance, and a different dominant gene is required for foliar resistance. In addition to these two genes, at least one dominant allele of a third gene must be present for expression of root rot and foliar blight resistance.

scholarly journals Inheritance of Phytophthora Stem Blight Resistance as Compared to Phytophthora Root Rot and Phytophthora Foliar Blight Resistance in Capsicum annuum L.

2005 ◽  
Vol 130 (1) ◽  
pp. 75-78 ◽  
Author(s):  
Ousmane Sy ◽  
Paul W. Bosland ◽  
Robert Steiner
Keyword(s):  
Root Rot ◽  
Single Gene ◽  
Phytophthora Capsici ◽  
Blight Resistance ◽  
Limiting Factor ◽  
Stem Cuttings ◽  
Phytophthora Root Rot ◽  
Stem Blight ◽  
Foliar Blight ◽  
Genetic Mechanisms

The pathogen Phytophthora capsici Leon. is known to be a limiting factor of chile pepper (Capsicum L.) production around the world. The genetics of the resistance is becoming better understood due to the specific nature of the host-pathogen interaction, i.e., all plant organs are subject to infection. It has been shown that phytophthora root rot resistance and phytophthora foliar blight resistance are under different genetic mechanisms. This study aimed at understanding the inheritance of resistance of phytophthora stem blight and to determine whether phytophthora stem blight was the same disease syndrome as phytophthora root rot and phytophthora foliar blight. Stem cuttings of a segregating F2 population and testcross progeny facilitated the ability to screen for two disease syndromes concurrently. When the three disease syndromes were compared separately, the F2 populations fit a 3 resistant (R): 1 susceptible (S) ratio and the testcross progenies fit a 1R:1S ratio. When comparative studies were performed (stem vs. foliar and stem vs. root), the F2 populations fit a 9R/R:3R/S:3S/R:1S/S ratio and the testcross fit a 1R/R:1R/S:1S/R:1S/S ratio. These ratios are consistent of a single gene controlling the resistance of each system. Therefore, phytophthora stem blight, root rot, and foliar blight are three separate disease syndromes.

scholarly journals Genetic Analysis of Phytophthora Root Rot Race-specific Resistance in Chile Pepper

2008 ◽  
Vol 133 (6) ◽  
pp. 825-829 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland
Keyword(s):  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Single Gene ◽  
Phytophthora Capsici ◽  
Segregation Ratio ◽  
Descent Method ◽  
Chile Pepper ◽  
Phytophthora Root Rot ◽  
Multiple Alleles ◽  
Seven Generations

Phytophthora capsici Leon., causal agent of phytophthora root rot, is one of the most devastating pathogens attacking chile pepper (Capsicum annuum L.) plants. Many studies have tried to better understand phytophthora resistance, but the genetic behavior is not completely understood. To determine if phytophthora root rot resistance in chile pepper is controlled by multiple alleles at a few loci, or multiple genes at different loci, five recombinant inbred lines (RILs) were evaluated. The resistant accession, Criollo de Morelos-334, and the susceptible cultivar, Early Jalapeno, were hybridized to develop multiple RILs. After seven generations of selfing using the single seed descent method, four RILs were selected based on their phenotypic response to inoculation by five P. capsici isolates. The RILs were hybridized to each other to obtain F1 and F2 populations. The F2 populations were inoculated with single and a pair of races of P. capsici. When the F2 populations were inoculated with a single race, ratios of three resistant:one susceptible were obtained in the majority of the populations, indicating the action of an independent single gene. When the F2 populations were inoculated with a combination of two races, segregation ratios of 15 resistant:one susceptible were observed in two populations out of the four populations. The presence of susceptible individuals in all of the F2 population indicates that the resistant genes for the different P. capsici races are located at different loci. However, the rejection of the segregation ratio in one of the F2 population under a single race inoculation and in two of the F2 populations challenged with a combination of two races suggest a linkage phenomenon between some of the R genes. None of the RILs evaluated in this study displayed allelism for phytophthora root rot resistance.

scholarly journals Phytophthora Root Rot Resistance and Its Correlation with Fruit Rot Resistance in Capsicum annuum

HortScience ◽  
2020 ◽  
Vol 55 (12) ◽  
pp. 1931-1937
Author(s):  
Rachel P. Naegele ◽  
Mary K. Hausbeck
Keyword(s):  
Broad Spectrum ◽  
Root Rot ◽  
Partial Resistance ◽  
Phytophthora Capsici ◽  
Fruit Rot ◽  
Multiple Sources ◽  
Sources Of Resistance ◽  
Phytophthora Root Rot ◽  
Foliar Blight ◽  
Moderate Resistance

Phytophthora capsici causes root and fruit rot and foliar blight of pepper. Multiple sources of resistance to Phytophthora root rot have previously been identified, but most display only partial resistance. One source, CM334, has broad spectrum root rot resistance to multiple pathogen isolates but has only low to moderate fruit rot resistance. This study evaluated previously identified pepper lines for resistance to two P. capsici isolates, OP97 and 12889, and compared root rot resistance to fruit rot resistance and genetic structure. CM334 was confirmed as a broad spectrum resistance genotype, whereas all other sources of resistance evaluated were susceptible to infection by one or both isolates evaluated. Although not completely resistant, PI 566811 displayed moderate resistance to fruit and root rot to both P. capsici isolates. Fruit rot resistance had a significant but small to moderate positive correlation (r = 0.26–0.63) with root rot resistance depending on the isolate and length of exposure. Pepper accessions with resistance to Phytophthora root and fruit rot belonging to different genetic subpopulations were identified and could serve as candidates for partial-resistance loci to incorporate into pepper breeding programs.

scholarly journals Differentiation of Race Specific Resistance to Phytophthora Root Rot and Foliar Blight in Capsicum annuum

2003 ◽  
Vol 128 (2) ◽  
pp. 213-218 ◽  
Author(s):  
Lisa M. Oelke ◽  
Paul W. Bosland ◽  
Robert Steiner
Keyword(s):  
New Mexico ◽  
Capsicum Annuum ◽  
Root Rot ◽  
Specific Resistance ◽  
Phytophthora Capsici ◽  
Significant Implication ◽  
Phytophthora Root Rot ◽  
Physiological Races ◽  
Foliar Blight ◽  
Extensive Breeding

Despite extensive breeding efforts, no pepper (Capsicum annuum L. var. annuum) cultivars with universal resistance to phytophthora root rot and foliar blight (Phytophthora capsici Leon) have been commercially released. A reason for this limitation may be that physiological races exist within P. capsici, the causal agent of phytophthora root rot and phytophthora foliar blight. Physiological races are classified by the pathogen's reactions to a set of cultivars (host differential). In this study, 18 varieties of peppers were inoculated with 10 isolates of P. capsici for phytophthora root rot, and four isolates of P. capsici for phytophthora foliar blight. The isolates originated from pepper plants growing in New Mexico, New Jersey, Italy, Korea, and Turkey. For phytophthora root rot, nine of the 10 isolates were identified as different physiological races. The four isolates used in the phytophthora foliar blight study were all determined to be different races. The identification of physiological races within P. capsici has significant implication in breeding for phytophthora root rot and phytophthora foliar blight resistance.

scholarly journals Evaluating the Efficacy of the Systems Approach at Mitigating Five Common Pests in Oregon Nurseries

2014 ◽  
Vol 32 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Nancy K. Osterbauer ◽  
Melissa Lujan ◽  
Gary McAninch ◽  
S. Lane ◽  
Aaron Trippe
Keyword(s):  
Root Rot ◽  
Systems Approach ◽  
Phytophthora Root Rot ◽  
Potted Plants ◽  
Foliar Blight ◽  
Total Percentage ◽  
Phytophthora Spp ◽  
Root Weevils ◽  
Pest Incidence ◽  
Point Inspection

In Oregon, the U.S. Nursery Certification (USNCP), Grower Assisted Inspection (GAIP), and Shipping Point Inspection (SPI) programs are used to certify nursery plants as pest free. To compare the programs' effectiveness for mitigating pest risk, potted plants grown within two USNCP, two GAIP, and two SPI nurseries were surveyed for Phytophthora root rot (Phytophthora spp.), Phytophthora foliar blight (Phytophthora spp.), bittercress (Cardamine spp.), snails and slugs (Class Gastropoda), and root weevils (Otiorhynchus spp.). A total of 1,635 plots were surveyed in the nurseries, with one or more pests detected in 1,003 plots. Based on the total percentage of plots found infested with a pest, significantly fewer were detected in the GAIP nurseries (55%) than in the USNCP nurseries (68%). However, bittercress incidence was significantly higher in GAIP nurseries (21%), while snails and slugs incidence was significantly higher in USNCP nurseries (49%), and Phytophthora root rot incidence was significantly higher in SPI nurseries (31%). Also, the plant families grown by the nurseries had a significant impact on pest incidence for two of the target pests, Phytophthora root rot and root weevils. While the GAIP seemed the best at mitigating pest incidence overall, none of the certification programs was consistently the most effective against all five target pests.

scholarly journals An Inexpensive Disease Screening Technique for Foliar Blight of Chile Pepper Seedlings

HortScience ◽  
1994 ◽  
Vol 29 (10) ◽  
pp. 1182-1183 ◽  
Author(s):  
Tito P. Alcantara ◽  
Paul W. Bosland
Keyword(s):  
Root Rot ◽  
Fungal Pathogen ◽  
Phytophthora Capsici ◽  
Symptom Development ◽  
Sources Of Resistance ◽  
Screening Technique ◽  
Land Race ◽  
Foliar Blight ◽  
Leaf Surfaces ◽  
Test Plants

An inexpensive, rapid, and reliable seedling screening technique was developed to identify sources of resistance to foliar blight of Capsicum annuum L. caused by the fungal pathogen Phytophthora capsici Leon. Leaf surfaces of test plants were inoculated with 500 to 1000 zoospores prepared in distilled water. Seedlings were incubated for 5 days in an easy-to-construct dew chamber and observed for symptom development. `Criollo de Morelos 334' chile seedlings, a Mexican land race resistant to root rot caused by the same fungal pathogen, were highly resistant to foliar blight. All commercial cultivars tested in this study, however, were highly susceptible. No root rot symptoms were observed in any of the foliar-inoculated plants.

scholarly journals A Rapid Technique for Multiple-race Disease Screening of Phytophthora Foliar Blight on Single Capsicum annuum L. Plants

HortScience ◽  
2010 ◽  
Vol 45 (10) ◽  
pp. 1563-1566 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland
Keyword(s):  
Capsicum Annuum ◽  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Phytophthora Capsici ◽  
Pepper Plant ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Physiological Races ◽  
Foliar Blight

Phytophthora blight, caused by the oomycete Phytophthora capsici Leon., is a major disease that threatens production and long-term viability of the chile pepper (Capsicum annuum L.) industry. For each phytophthora disease syndrome such as root rot, foliar blight, and stem blight separate and independent resistant systems have evolved in the host. In addition, several physiological races of the pathogen have been identified. A novel, effective, and accurate screening technique is described that allows for multiple races to be evaluated on a single plant of C. annuum. The P. capsici resistant line Criollo de Morelos-334, a susceptible cultivar, Camelot, and three New Mexico Recombinant Inbred Lines, -F, -I, -S, were used to evaluate the new technique for phytophthora foliar blight multiple-race screening. Using three P. capsici physiological races, no interaction among the physiological races was observed with this technique. This novel technique provided a rapid disease screen evaluating multiple physiological races for phytophthora foliar blight resistance in a single chile pepper plant and can assist plant breeders in selecting for disease-resistant plants.

Ultrastructural changes in roots of peppers resistant and susceptible to Phytophthora capsici

1995 ◽  
Vol 53 ◽  
pp. 982-983
Author(s):  
H. Ilarslan ◽  
A.S. Ustun ◽  
R. Yilmazer
Keyword(s):  
Root Rot ◽  
Host Plants ◽  
Phytophthora Capsici ◽  
Host Cells ◽  
Ultrastructural Changes ◽  
Ultrastructural Examination ◽  
Susceptible Host ◽  
Ultrastructural Studies ◽  
Foliar Blight ◽  
Crown And Root Rot

The infection by Phytophthora capsici Leonian causes foliar blight and crown and root rot of pepper plants. The ultrastructural examination of resistant and susceptible host-pathogen interactions was conducted in the pepper cultivars Ince Sivri-35, PM217, and PM702=CM 334 following inoculation with Phytophthora capsici. Responses were characterized and compared with healthy non-inoculated controls at 2,4 and 6 days after inoculation. Numerous ultrastructural studies have been made of the interaction of various host plants Phytophthora spp. No ultrastructural studies comparing the resistant and susceptible reactions of pepper cultivars to P. capsici. have been reported. It is important to examine the ultrastructural changes in inoculated and infected tissue of resistant and susceptible pepper cultivars to P. capsici. Information reported here characterizes the processes of pathogen containment in resistant interactions and compares these with the processes occuring in susceptible interactions.After 2 days in susceptible interactions, the pathogen grew intercellularly in roots, whereas in resistant interactions only a few intercellular hyphae were observed penetrating the host cells and forming haustoria.

Detached-petiole inoculation method to evaluate Phytophthora root rot resistance in soybean plants

2017 ◽  
Vol 68 (6) ◽  
pp. 555
Author(s):  
Yinping Li ◽  
Suli Sun ◽  
Chao Zhong ◽  
Zhendong Zhu
Keyword(s):  
Root Rot ◽  
Dominant Gene ◽  
Phytophthora Sojae ◽  
Single Dominant Gene ◽  
Phytophthora Root Rot ◽  
Inoculation Methods ◽  
Inoculation Technique ◽  
Soybean Cultivars ◽  
F2 Population ◽  
Soybean Resistance

Phytophthora root rot (PRR) caused by Phytophthora sojae, is one of the most destructive soybean diseases. The deployment of resistant cultivars is an important disease management strategy. To this aim, the development of a fast and effective method to evaluate soybean resistance to P. sojae is strategic. In this study, a detached-petiole inoculation technique was developed and its reliability was verified in soybean cultivars and segregant populations for PRR resistance. The detached-petiole and hypocotyl inoculation methods were used to assess the resistance of soybean cultivars, the F2 population of a Zhonghuang47 × Xiu94-11 cross, and the derived F2:3 population. The reactions of 13 analysed cultivars to three P. sojae isolates were consistent between the two inoculation techniques. The reactions of the F2 and F2:3 populations to isolate PsMC1 were 95.20% similar between the two inoculation methods. The segregation of the resistance and susceptibility fit a 3 : 1 ratio. Our results suggest that the detached-petiole technique is a reliable method, and reveal that the PRR resistance in Xiu94-11 is controlled by a single dominant gene. The phenotypic ratios of the tested Jikedou2 × Qichadou1 F2 population using the detached-petiole inoculation technique fit a 3 : 1 ratio (Resistance : Susceptibility). This demonstrated that Qichadou1 contains a single dominant gene conferring resistance to P. sojae. Our new detached-petiole inoculation technique is effective, reliable, non-destructive to the plant, and does not require an excessive amount of seeds. It may be suitable for the largescale screening of soybean resistance to multiple P. sojae isolates.

scholarly journals Resistance to Crown and Root Rot Caused by Phytophthora capsici in a Tomato Advanced Backcross of Solanum habrochaites and Solanum lycopersicum

Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 829-835 ◽  
Author(s):  
L. M. Quesada-Ocampo ◽  
A. M. Vargas ◽  
R. P. Naegele ◽  
D. M. Francis ◽  
M. K. Hausbeck
Keyword(s):  
Root Rot ◽  
Phytophthora Capsici ◽  
Defense Responses ◽  
Vegetable Crops ◽  
Backcross Population ◽  
Phytophthora Root Rot ◽  
Disease Response ◽  
Advanced Backcross ◽  
Solanum Habrochaites ◽  
Crown And Root Rot

Phytophthora capsici causes devastating disease on many vegetable crops, including tomato and other solanaceous species. Solanum habrochaites accession LA407, a wild relative of cultivated tomato, has shown complete resistance to four P. capsici isolates from Michigan cucurbitaceous and solanaceous crops in a previous study. Greenhouse experiments were conducted to evaluate 62 lines of a tomato inbred backcross population between LA407 and the cultivated tomato ‘Hunt 100’ and ‘Peto 95-43’ for resistance to two highly virulent P. capsici isolates. Roots of 6-week-old seedlings were inoculated with each of two P. capsici isolates and maintained in the greenhouse. Plants were evaluated for wilting and plant death three times per week for 5 weeks. Significant differences were observed in disease response among the inbred tomato lines. Most lines evaluated were susceptible to P. capsici isolate 12889 but resistant to isolate OP97; 24 tomato lines were resistant to both isolates. Heritability of Phytophthora root rot resistance was high in this population. Polymorphic molecular markers located in genes related to resistance and defense responses were identified and added to a genetic map previously generated for the population. Resistant lines and polymorphic markers identified in this study are a valuable resource for development of tomato varieties resistant to P. capsici.

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