scholarly journals Comparison of Resistant Cultivars for Management of Bacterial Spot in Peppers

1999 ◽  
Vol 9 (4) ◽  
pp. 645-655
Author(s):  
Brent Rowell ◽  
R. Terry Jones ◽  
William Nesmith ◽  
John C. Snyder
Keyword(s):  
Capsicum Annuum ◽  
Xanthomonas Campestris ◽  
Bell Pepper ◽  
Bacterial Spot ◽  
Eastern Kentucky ◽  
Breeding Lines ◽  
Resistant Cultivars ◽  
Bacterial Spot Resistance ◽  
Free Environment

Bacterial spot epidemics, caused by Xanthomonas campestris pv. vesicatoria (Doidge) Dye, continue to plague bell pepper (Capsicum annuum L.) growers in a number of southern and midwestern states. A 3-year study designed to compare cultivars and breeding lines under induced bacterial spot epidemic and bacterial spot-free conditions began soon after the first release of cultivars having the Bs2 gene for resistance to races 1 to 3 of the pathogen. Bacterial spot epidemics were created by transplanting `Merlin' plants (inoculated with races 1 to 3) into plots of each test cultivar at an isolated location in eastern Kentucky. Plots of the same trial entries at a second location were kept free of bacterial spot for 2 of the 3 years of trials; however, a moderate natural epidemic occurred at this location in 1996. Bacterial spot resistance had the greatest impact on yields and returns per acre in the inoculated trials. Cultivars with only Bs1 or a combination of Bs1 and Bs3 were highly susceptible in the inoculated trials. There were statistically significant and economically important differences in resistance among cultivars and breeding lines having the Bs2 gene; some were nearly as susceptible as susceptible checks. Although many Bs2-gene cultivars showed satisfactory levels of resistance, only a few were highly resistant, horticulturally acceptable, and comparable in yields to the best susceptible hybrids in a bacterial spot-free environment.

scholarly journals Bacterial Spot Resistance, Yield, and Quality of Bell and Specialty Peppers

2001 ◽  
Vol 11 (4) ◽  
pp. 648-657 ◽  
Author(s):  
Brent Rowell ◽  
R. Terry Jones ◽  
William Nesmith ◽  
April Satanek ◽  
John C. Snyder
Keyword(s):  
Capsicum Annuum ◽  
Fruit Quality ◽  
Xanthomonas Campestris ◽  
Bell Pepper ◽  
Bacterial Spot ◽  
Eastern Kentucky ◽  
Resistant Cultivars ◽  
Yield And Quality ◽  
Bacterial Spot Resistance

Bacterial spot epidemics, caused by Xanthomonas campestris pv. vesicatoria (Xcv), are still considered serious risks for commercial pepper (Capsicum annuum) growers in a number of eastern, southern and midwestern states. Newly released bell pepper cultivars with the Bs2 gene for resistance to Xcv races 1, 2, and 3 were compared in 2000 under bacterial spot-free and severe (natural) bacterial spot epidemic conditions in central and eastern Kentucky where similar trials had been conducted from 1995 to 1997. In addition to the replicated bell pepper trials, 49 hot and specialty pepper cultivars were grown for observation in single plots at the same two locations. As in previous trials, there were economically important differences in resistance and marketable yields among bell pepper cultivars having the Bs2 gene; some resistant cultivars were as susceptible as susceptible checks. Others were highly resistant in spite of the presence of Xcv races 3 and 6 in the eastern Kentucky trial. Only a few were highly resistant with excellent fruit quality. With a few notable exceptions, most of the hot and specialty cultivars were very susceptible to bacterial spot. Two of the three new jalapeño cultivars carrying Bs2 were highly resistant to bacterial spot and high yielding under severe epidemic conditions.

scholarly journals Field Tolerance of Bell Pepper Cultivars to Bacterial Leaf Spot under Epidemic Conditions

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 568f-569
Author(s):  
Brent Rowell ◽  
R. Terry Jones ◽  
William Nesmith
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Field Resistance ◽  
Fresh Market ◽  
Bacterial Leaf Spot ◽  
Breeding Lines ◽  
Epidemic Development ◽  
Race 2 ◽  
Free Environment ◽  
Disease Free

Bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vesicatoria is the scourge that has devastated and continues to limit expansion of both fresh-market and processing pepper production in Kentucky. Fourteen new BLS-resistant varieties and breeding lines were evaluated together with two standard (susceptible) varieties in 1995 at two locations. Twenty advanced lines and commercial varieties were tested at the same locations in 1996. All entries were exposed to an induced BLS epidemic at one location, but were kept disease-free at the second location. Epidemic development was slow and field resistance to four races of BLS was high for all but one of the lines tested, which claimed resistance to races 1, 2, and 3 in 1995. Six entries performed well both under BLS epidemic conditions and in the disease-free environment in 1995. Cultivars with resistance to only race 2 or races 1 and 2 of the pathogen were no different from susceptible checks in terms of yields and disease resistance and were not tested in 1996; combined results form 1995 and 1996 are discussed.

scholarly journals Tomato Bacterial Spot Resistance Derived from PI 114490; Inheritance of Resistance to Race T2 and Relationship across Three Pathogen Races

2003 ◽  
Vol 128 (5) ◽  
pp. 698-703 ◽  
Author(s):  
J.W. Scott ◽  
D.M. Francis ◽  
S.A. Miller ◽  
G.C. Somodi ◽  
J.B. Jones
Keyword(s):  
Disease Severity ◽  
Xanthomonas Campestris ◽  
The Other ◽  
Bacterial Spot ◽  
Resistance Level ◽  
Narrow Sense Heritability ◽  
Backcross Population ◽  
Locus Model ◽  
Bacterial Spot Resistance ◽  
Inbred Backcross

Crosses were made between tomato (Lycopersicon esculentum Mill.) inbreds susceptible to races T2 and T3 of bacterial spot (Xanthomonas vesicatoria and Xanthomonas campestris pv. vesicatoria, respectively) and accession PI 114490 with resistance to races T1, T2, and T3. Resistance to race T2 was analyzed using the parents, F1, and F2 generations from one of the crosses. The F1 was intermediate between the parents for disease severity suggesting additive gene action. The segregation of F2 progeny fit a two-locus model (χ2 = 0.96, P = 0.9-0.5) where four resistance alleles are required for a high resistance level, two or three resistance alleles provide intermediate resistance, and zero or one resistance allele results in susceptibility. The narrow sense heritability of resistance to T2 strains was estimated to be 0.37 ± 0.1 based on F2 to F3 parent-offspring regression. A second cross was developed into an inbred backcross (IBC) population to facilitate multilocation replicated testing with multiple races. Segregation for T2 resistance in the inbred backcross population also suggested control was by two loci, lending support to the two-locus model hypothesized based on the F2 segregation. To determine if the same loci conferred resistance to the other races, selections for race T2 resistance were made in the F2 and F3 generations and for race T3 resistance in the F2 through F4 generations. Six T3 selections (F5), 13 T2 selections (F4's that diverged from seven F2 selections), and control lines were then evaluated for disease severity to races T1, T2, and T3 over two seasons. Linear correlations were used to estimate the efficiency of selecting for resistance to multiple races based on a disease nursery inoculated with a single race. Race T1 and race T2 disease severities were correlated (r ≥ 0.80, P< 0.001) within and between years while neither was correlated to race T3 either year. These results suggest that selecting for race T2 resistance in progeny derived from crosses to PI 114490 would be an effective strategy to obtain resistance to both race T1 and T2 in the populations tested. In contrast, selection for race T3 or T2 will be less likely to result in lines with resistance to the other race. PI 114490 had less resistance to T3 than to T2 or T1. Independent segregation of T2 and T3 resistance from the IBC population derived from PI 114490 suggests that T3 resistance is not controlled by the same genes as T2 resistance, supporting the linear correlation data.

scholarly journals Genetic Mapping and Functional Analysis of the Tomato Bs4 Locus Governing Recognition of the Xanthomonas campestris pv. vesicatoria AvrBs4 Protein

2001 ◽  
Vol 14 (5) ◽  
pp. 629-638 ◽  
Author(s):  
Agim Ballvora ◽  
Michéle Pierre ◽  
Guido van den Ackerveken ◽  
Sebastian Schornack ◽  
Ombeline Rossier ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Resistance Locus ◽  
Bacterial Spot ◽  
Dna Templates ◽  
Nuclear Localization Signals ◽  
Bulked Dna ◽  
Capsicum Spp ◽  
Bacterial Spot Disease ◽  
Bacterial Spot Resistance ◽  
Susceptible Tomato

Xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper (Capsicum spp.) and tomato (Lycopersicon spp.). Analysis of 17 different Lycopersicon accessions with avrBs4-expressing X. campestris pv. vesicatoria strains identified 15 resistant and two susceptible tomato genotypes. Genetic analysis revealed that AvrBs4 recognition in tomato is governed by a single locus, designated Bs4 (bacterial spot resistance locus no. 4). Amplified fragment length polymorphism and bulked DNA templates from resistant and susceptible plants were used to define a 2.6-cM interval containing the Bs4 locus. A standard tomato mapping population was employed to localize Bs4- linked markers on the short arm of chromosome 5. Investigation of X. campestris pv. vesicatoria hrp mutant strains revealed that AvrBs4 secretion and avirulence activity are hrp dependent. Agrobacterium-based delivery of the avrBs4 gene into tomato triggered a plant response that phenotypically resembled the hypersensitive response induced by avrBs4-expressing X. campestris pv. vesicatoria strains, suggesting symplastic perception of the avirulence protein. Mutations in the avrBs4 C-terminal nuclear localization signals (NLSs) showed that NLSs are dispensable for Bs4-mediated recognition. Our data suggest that tomato Bs4 and pepper Bs3 employ different recognition modes for detection of the highly homologous X. campestris pv. vesicatoria avirulence proteins AvrBs4 and AvrBs3.

scholarly journals Inheritance of bacterial spot resistance in Capsicum annuum var. annuum

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
L.R.A. Silva ◽  
R. Rodrigues ◽  
S. Pimenta ◽  
J.W.S. Correa ◽  
M.S.B. Araújo ◽  
...  
Keyword(s):  
Capsicum Annuum ◽  
Bacterial Spot ◽  
Bacterial Spot Resistance

scholarly journals Comparison of Greenhouse Methods for Assessing Resistance to Bacterial Leaf Spot in Plum

1993 ◽  
Vol 118 (5) ◽  
pp. 667-671 ◽  
Author(s):  
B.L. Topp ◽  
W.B. Sherman ◽  
R.E. Stall ◽  
G.V. Minsavage ◽  
C.J. Wilcox
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Field Performance ◽  
Bacterial Spot ◽  
Plant Genotype ◽  
Adaxial Side ◽  
Prunus Salicina ◽  
Leaf Mesophyll ◽  
Bacterial Spot Resistance ◽  
Spearman’S Correlation

Four greenhouse leaf inoculation methods for screening Japanese plum (Prunus salicina L. and hybrids) for resistance to Xanthomonas campestris pv. pruni (Smith) Dye were compared for repeatability, ability to differentiate among plant genotype responses, and correlations with field ratings. Clonally propagated trees were inoculated artificially in a greenhouse by immersing leaves in 2.5 × 108 cfu/ml inoculum (DIP), rubbing the adaxial side of leaves with a slurry of 2.5 × 108 cfu/ml inoculum and Carborundum powder (CARB), infiltrating leaves with 5 × 105 cfu/ml inoculum using a needle-less syringe (INFS), and infiltrating with 5 × 106 cfu/ml inoculum (INF6). No greenhouse method was superior in all assessment categories. The CARB method was most repeatable (t = 0.78) but had a low Spearman's correlation (rs = 0.29), indicating that greenhouse rankings did not correspond closely with field rankings. The INF6 method was unsuitable because it did not differentiate between plant genotypes. The DIP method appeared most suitable, having moderate repeatability (t = 0.46) for four observations per leaf and moderate Spearman's correlation with field performance (rs = 0.56). The INF5 method may be appropriate for identifying bacterial spot resistance that is associated with resistance in the leaf mesophyll.

scholarly journals RESISTANCE TO BACTERIAL SPOT IN CUCURBITA SPECIES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1064d-1064
Author(s):  
Dermot P. Coyne ◽  
Lisa Sutton ◽  
Debra Fujimoto
Keyword(s):  
Xanthomonas Campestris ◽  
Block Design ◽  
Bacterial Spot ◽  
Sources Of Resistance ◽  
Breeding Lines ◽  
Disease Reaction ◽  
Round Shape ◽  
Randomized Complete Block Design ◽  
Early Maturing ◽  
Greenhouse Tests

No sources of resistance to Xanthomonas campestris pv. cucurbitae (X.c.c.) in the Cucurbita species have been reported. Cultivars, breeding lines, landraces, and PI lines of 5 Cucurbita species were screened for resistance to X.c.c. in 3 greenhouse tests (GH). A `florist`s frog' was used to inoculate the first fully expanded leaves using a X.c.c. suspension (107 CFU/ml). The disease reaction was recorded as the percentage of inoculated leaf area with necrotic lesions and/or chlorosis. Butternut (b n) breeding lines were also evaluated for reaction to X.c.c. under uniform natural in feetion in 2 field (F) trials. A randomized complete block design was used in all GH and F experiments. C. moschata Nebr. BN PM1-88-8 and C. martinezii had high resistance to X.c.c. All other entries in all tests were susceptible. BN PM-88-8 is an early maturing small stable (no crookneck fruit) near-round BN type squash. The fruit are resistant to black–rot, but the leaves are susceptible to powdery mildew. BN PM-88-8 is ideal for microwave cooking because of its near-round shape permitting more uniform cooking. Release is expected in 1990.

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