scholarly journals Reactions in the Annual Medicago spp. Core Germ Plasm Collection to Phoma medicaginis

Plant Disease ◽  
2003 ◽  
Vol 87 (5) ◽  
pp. 557-562 ◽  
Author(s):  
Nichole R. O'Neill ◽  
Gary R. Bauchan ◽  
Deborah A. Samac
Keyword(s):  
Disease Resistance ◽  
Leaf Spot ◽  
Core Collection ◽  
Germ Plasm ◽  
Severity Scale ◽  
Forage Crop ◽  
The Core ◽  
Phoma Medicaginis ◽  
Disease Severity Scale ◽  
Annual Medicago

The annual Medicago spp. core collection, consisting of 201 accessions, represents the genetic diversity inherent in 3,159 accessions from 36 annual Medicago spp. This germ plasm was evaluated for resistance to spring black stem and leaf spot caused by Phoma medicaginis. Spring black stem and leaf spot is a major destructive disease in perennial alfalfa (Medicago sativa) grown in North America, Europe, and other temperate regions. Disease control is based principally on the use of cultivars with moderate levels of resistance. Evaluation of the core collection was conducted using standardized environmental conditions in growth chambers, and included the M. sativa standard reference cultivars Ramsey (resistant) and Ranger (susceptible). The degree of resistance found among accessions within species was variable, but most annual species and accessions were susceptible. Most accessions from 10 species exhibited high disease resistance. These included accessions of M. constricta, M. doliata, M. heyniana, M. laciniata, M. lesinsii, M. murex, M. orbicularis, M. praecox, M. soleirolii, and M. tenoreana. Most of the accessions within M. arabica, M. minima, M. lanigera, M. rotata, M. rugosa, M. sauvagei, and M. scutellata were highly susceptible. Disease reactions among some accessions within species were highly variable. On a 0-to-5 disease severity scale, ratings ranged from 0.67 (PI 566873) to 4.29 (PI 566883) within accessions of M. polymorpha. Most of the M. truncatula accessions were susceptible, with a mean of 3.74. Resistant reactions were similar to those found in incompatible interactions with P. medicaginis and alfalfa, which have been associated with specific genes leading to the production of isoflavonoid phytoalexins. The large genetic variability in annual Medicago spp. offers potential for locating and utilizing disease resistance genes through breeding or genetic engineering that will enhance the utilization of Medicago spp. as a forage crop.

scholarly journals Sources of Resistance to Anthracnose in the Annual Medicago Core Collection

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Nichole R. O'Neill ◽  
Gary R. Bauchan
Keyword(s):  
Core Collection ◽  
Seedling Survival ◽  
Plant Introduction ◽  
Sources Of Resistance ◽  
Forage Crop ◽  
Colletotrichum Trifolii ◽  
Resistant Varieties ◽  
Medicago Sativa L ◽  
Annual Medicago ◽  
Medicago Species

The annual genus Medicago core collection, consisting of 201 accessions, represents the genetic diversity inherent in 3,159 accessions from 36 annual Medicago species. This germ plasm was evaluated for resistance to anthracnose caused by Colletotrichum trifolii. Anthracnose is a major disease in perennial alfalfa (Medicago sativa L.) grown in North America and disease control is based principally on the use of resistant varieties. Evaluation of the core collection was conducted using standardized environmental conditions in growth chambers, and included the M. sativa standard reference cvs. Arc (resistant) and Saranac (susceptible). The degree of resistance found among accessions within species was highly variable; however, most annual species and accessions were susceptible. Only 14 accessions from seven species exhibited resistance greater than 40% seedling survival. These included accessions of M. murex, M. muricoleptis, M. polymorpha var. brevispina, M. polymorpha var. polymorpha, M. radiata, M. soleirolii, M. truncatula, and M. turbinata. Of the 12 accessions of M. polymorpha var. polymorpha, 4 exhibited more than 50% resistance, but 3 accessions were 100% susceptible. Most of the M. truncatula and M. turbinata accessions exhibited significantly more resistance than accessions of other species. Plant introduction (PI) accession number PI 495401 of M. muricoleptis exhibited 90.3% resistance. Accessions of M. scutellata were uniformly susceptible. Histological examinations of 14 of the most anthracnose-resistant accessions revealed that C. trifolii spores germinated and produced typical appressoria, but failed to penetrate and produce the primary and secondary hyphae characteristic of susceptible interactions. Resistant reactions were similar to those found in incompatible interactions with C. trifolii and alfalfa, which have been associated with specific genes leading to the production of isoflavonoid phytoalexins. The large genetic variability in annual Medicago spp. offers potential for locating and utilizing disease resistance genes through breeding or genetic engineering that will enhance the utilization of Medicago spp. as a forage crop.

scholarly journals The Formation of Test Arrays and a Core Collection in Cucumber Using Phenotypic and Molecular Marker Data

2002 ◽  
Vol 127 (4) ◽  
pp. 558-567 ◽  
Author(s):  
Jack E. Staub ◽  
Fenny Dane ◽  
Kathleen Reitsma ◽  
Gennaro Fazio ◽  
Anabel López-Sesé
Keyword(s):  
Genetic Diversity ◽  
Heat Stress ◽  
Disease Resistance ◽  
Downy Mildew ◽  
Core Collection ◽  
Genetic Relationships ◽  
Population Variation ◽  
Fruit Rot ◽  
Plant Introductions ◽  
The Core

Genetic relationships among 970 cucumber (Cucumis sativus L.) plant introductions (PIs) in the U.S. National Plant Germplasm System (NPGS) were assessed by observing variation at 15 isozyme loci. Allozyme frequency data for these PIs were compared to allozyme variation in heirloom and modern (H&M) cultivars released from 1846-1985 (H&M cultivars; 178 accessions), and experimental commercial (EC) germplasm (EC germplasm; 82 accessions) in use after 1985. Multivariate analysis defined four distinct groups of accessions (Groups A-D), where Group A consisted of PIs received by the NPGS before 1992, Group B contained PIs from India and China obtained by NPGS after 1992, Group C consisted of EC germplasm, and Group D contained H&M cultivars. Morphological, abiotic stress (water and heat stress tolerance) and disease resistance evaluation data from the Germplasm Resources Information Network (GRIN) for the PIs examined were used in conjunction with estimates of population variation and genetic distance estimates to construct test arrays and a core collection for cucumber. Disease resistance data included the evaluation of angular leafspot [Pseudomonas lachrymans (E.F. Smith) Holland], anthracnose [Colletotrichum lagenarium (Ross.) Ellis & Halst], downy mildew [Pseudoperonospora cubensis (Berk. & Curt) Rostow], rhizoctonia fruit rot (Rhizoctonia solani Kuhn), and target leafspot [Corynespora cassiicola (Berk. & Curt) Wei] pathogenicity. The test arrays for resistance-tolerance to angular leafspot, anthracnose, downy mildew, rhizoctonia fruit rot, target leafspot, and water and heat stress consisted of 17, 16, 17, 16, 17, 16, and 16 accessions, respectively. The core collection consisted of accessions in these test arrays (115) and additional 32 accessions that helped circumscribe the genetic diversity of the NPGS collection. The core collection of 147 accessions (115 + 32) represents ≈11% of the total collection's size (1352). Given estimates of genetic diversity and theoretical retention of diversity after sampling, this core collection could increase curatorial effectiveness and the efficiency of end-users as they attempt to identify potentially useful germplasm.

Resistance in annual Medicago species to Phoma medicaginis and Leptosphaerulina trifolii under field conditions

1995 ◽  
Vol 35 (2) ◽  
pp. 209 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Disease Resistance ◽  
Field Conditions ◽  
Breeding Lines ◽  
Disease Progress Curve ◽  
Leaf Disease ◽  
Progress Curve ◽  
Phoma Medicaginis ◽  
Annual Medicago ◽  
Medicago Species ◽  
New Cultivars

Advanced breeding lines and potential new cultivars of annual Medicago species were screened for resistance to phoma leaf and stem disease (caused by Phoma medicaginis) and pepper spot (caused by Leptosphaerulina trifolii) in the field, and their performances were compared with appropriate control cultivars. Medicago murex had the best overall disease resistance of the Medicago species tested. There were large differences between varieties in the incidence of both diseases. Based on end-of-season scores, the most resistant to phoma leaf disease included M. murex cv. Zodiac and SAR 3490, M. tornata SA10012, and M. truncatula cv. Parabinga, with scores 52.8 on a 0-10 scale (0, nil disease; 10, >90% leaves affected). On the basis of area under disease progress curve (AUDPC), the most resistant to phoma leaf disease, with AUDPC values of <157, included all M. murex varieties except 87FB2.30, and M. truncatula cv. Caliph. Based on end-of-season scores, the most resistant to phoma stem disease, all with scores c4, included M. murex cv. Zodiac, SAR 3490, and 87F01.48; M. sphaerocarpos cv. Orion (SEP 29.1), SEP 29.2, and SEP 30.3; and M. tornata cv. Tornafield and SA10012. Resistance to phoma stem disease in these lines was confirmed by AUDPC values, especially for M. murex cv. Zodiac, SAR3490, and 87FO1.48, and for M. tornata SA10012, with values <154. Based on end-of-season scores, the most resistant to pepper spot leaf disease included M. polymorpha cvv. Serena and Circle Valley, with scores 52.8. On the basis of AUDPC, all M. murex varieties except SAR3490 and 87FO1.5 could be included among those most resistant to pepper spot leaf disease, with AUDPC values <275. Coumestrol levels in stems ranged from 117 to 1420 mg/kg DW, with lowest levels (5330 mg/kg) in M. murex cv. Zodiac, 87FO 1.48, and GRC 87; M. sphaerocarpos cv. Orion (SEP 29.1), SEP 29.2, and SEP 26.2.1; M. tornata cv. Tornafield; and M. truncatula Z601. There was positive correlation between the severity of phoma disease on stems and end-of-season (September-November) coumestrol concentrations.

scholarly journals Identification of Sources of Multiple Disease Resistance in Mini-core Collection of Chickpea

Plant Disease ◽  
2006 ◽  
Vol 90 (9) ◽  
pp. 1214-1218 ◽  
Author(s):  
S. Pande ◽  
G. Krishna Kishore ◽  
H. D. Upadhyaya ◽  
J. Narayana Rao
Keyword(s):  
Disease Resistance ◽  
Fusarium Wilt ◽  
Root Rot ◽  
Core Collection ◽  
Germ Plasm ◽  
Gray Mold ◽  
Ascochyta Rabiei ◽  
Mini Core Collection ◽  
Multiple Disease Resistance ◽  
Moderately Resistant

Host plant resistance is the major component in the management of fungal diseases in chickpea (Cicer arietinum). We screened a chickpea mini-core collection composed of 211 germ plasm accessions representing the diversity of the global chickpea germ plasm collection of 16,991, maintained at the International Crops Research Institute for the Semi-Arid Tropics to identify sources of multiple disease resistance. The accessions were screened for resistance against As-cochyta blight (Ascochyta rabiei), Botrytis gray mold (Botrytis cinerea), Fusarium wilt (Fusarium oxysporum f. sp. ciceris), and dry root rot (Rhizoctonia bataticola) under a controlled environment. High levels of resistance were observed to Fusarium wilt (FW), where 21 accessions were asymptomatic and 25 resistant. In all, 3, 55, and 6 accessions were moderately resistant to Ascochyta blight (AB), Botrytis gray mold (BGM), and dry root rot (DRR) respectively. ICC 11284 was the only accession moderately resistant to both AB and BGM. Combined resistance also was identified for DRR and FW in 4 accessions, and for BGM and FW in 11 accessions. Through this study, chickpea germ plasm accessions were identified that possess high levels of resistance to more than one fungal disease and would be useful in chickpea multiple disease resistance breeding programs.

scholarly journals Evaluation of Disease Resistance among 57 Cultivars of Zinnia

2001 ◽  
Vol 11 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Linda Gombert ◽  
Mark Windham ◽  
Susan Hamilton
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Disease Severity ◽  
Xanthomonas Campestris ◽  
Zinnia Elegans ◽  
Severity Scale ◽  
Alternaria Blight ◽  
Erysiphe Cichoracearum ◽  
Landscape Use ◽  
Disease Severity Scale

Fifty-seven cultivars of zinnia (Zinnia elegans Jacq.) were studied for 17 weeks to determine their resistance to alternaria blight (Alternaria zinniae Pape), powdery mildew (Erysiphe cichoracearum DC ex Merat) and bacterial leaf & flower spot [Xanthomonas campestris pv. zinniae (syn. X. nigromaculans f. sp. zinniae Hopkins & Dowson)]. A disease severity scale was used to determine acceptability for landscape use. At week 4, all cultivars were acceptable. At week 10, eleven cultivars were acceptable. At week 17, all cultivars were unacceptable. Ten cultivars had been killed by one or more pathogens by week 17. Only two cultivars showed any tolerance to any disease (powdery mildew) at week 17.

scholarly journals Port Governance and Cruise Tourism

2021 ◽  
Vol 13 (9) ◽  
pp. 4877
Author(s):  
Alejandro Vega-Muñoz ◽  
Guido Salazar-Sepúlveda ◽  
Nicolás Contreras-Barraza ◽  
Lorena Araya-Silva
Keyword(s):  
Core Collection ◽  
Web Of Science ◽  
Selection Process ◽  
Meta Analysis ◽  
Eligibility Criteria ◽  
The Core ◽  
Cruise Ships ◽  
Governance Model ◽  
Cruise Tourism ◽  
Governance Models

Cruise activities, until 2020, have presented a significant increase in revenue, as well as number of cruises and passengers transported, and it has become a challenge for ports to respond to this demand for services. In response to this, the world’s ports have implemented different governance models. In this context, in this paper, we aim to review the different governance models, as well as port cooperation, competition, and stakeholders. For this purpose, using science metric meta-analysis, an article set is extracted that strictly refers to the governance model of two databases integrated into the Core Collection Web of Science, whose selection process is polished with the PRISMA guidelines, establishing the eligibility criteria of studies using PICOS tool, to which a qualitative meta-analysis is applied. A limited studies set is identified, that includes governance model implementations, private strategies and internalization patterns in the port sector and cruise ships, patterns of port cooperation and governance, governance models in cruise ports, structures and strategies, and changes in the cruise market. Finally, various governance model forms are determined, all documented in the scientific research worldwide, discussing the various components of study topics.

scholarly journals OP0009 DERIVATION AND VALIDATION OF THE SCLERODERMA LUNG 3-STAGE INDEX (SL3SI), A NEW FUNCTIONAL INDEX FOR INTERSTITIAL LUNG DISEASE WITH PROGNOSTIC IMPLICATIONS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 7.2-7
Author(s):  
A. Santaniello ◽  
C. Bellocchi ◽  
L. Bettolini ◽  
M. Cassavia ◽  
G. Montanelli ◽  
...  
Keyword(s):  
At Risk ◽  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Disease Severity ◽  
Disease Duration ◽  
Functional Model ◽  
Severity Scale ◽  
Predictive Capability ◽  
Patients At Risk ◽  
Disease Severity Scale

Background:The staging of interstitial lung disease (ILD) is important to monitor disease progression and for prognostication. A disease severity scale of Systemic Sclerosis (SSc)-related lung disease has long been proposed (i.e. Medsger’s severity scale). This scale was mostly developed by discussion and consensus and stage thresholds were not computed by a data-driven approach. Hidden Markov models (HMM) are methods to estimate population quantities for chronic diseases with a staged interpretation which are diagnosed by markers measured at irregular intervals.Objectives:To build a SSc-ILD specific disease severity scale with prognostic relevance via HMM modeling.Methods:A total of 358 SSc patients at risk for or with ILD were enrolled in a discovery (207 cases, Milan1) and in a validation (151 cases, Milan2, Pavia and Rome) cohort. Patients were included if satisfied the following criteria: 1) Diagnosis of SSc according to the EULAR/ACR 2013 criteria, 2) absence of anticentromere antibodies, 3) dcSSc subset or 4) other subsets with either 4a) ILD-related antibodies (Scl70, PmScl, Ku) or 4b) evidence of ILD on HRCT, 5) disease duration < 5 years at the time of the first pulmonary function test (PFT). Serial PFTs were retrieved and the time up to the last available visit -if the patient alive-, or to death due to pulmonary complications, was recorded. HMM were used to estimate the threshold of a 3-stage model (SL3SI, Scleroderma Lung 3-Stage Index) based on PFT functional values (normal/mild, moderate, severe involvement) in the discovery cohort. Survival estimates of the SL3SI model were compared to Medsger’s severity classes estimates and their predictive capability evaluated via the explained residual variation (R2) of prediction errors (the higher the better). One-hundred random replicates were generated to simulate the prediction effort in patients with different disease duration and lung severity.Results:Patients characteristics are summarized in the Table. Fifteen-years survival estimates for Mesdger’s classes in the discovery set were: normal=0.88, mild=0.86, moderate=0.84 and severe=0.71. The SL3SI was defined by the following thresholds: normal/mild, FVC and DLco >=75%; moderate FVC or DLco 74-55%; severe, FVC or DLco <55%. SL3SI 15-yrs survival estimates were: normal/mild=0.89, moderate=0.82 and severe=0.63. Prediction analysis showed a higher R2values at 15 yrs for the SL3SI compared to Medsger’s classes, providing evidence for a better predictive capability of the former (discovery: 0.31 vs 0.25; validation: 0.28 vs 0.19).Conclusion:The SL3SI, a simplified 3-stage functional model of SSc-ILD, yields better survival estimates and long-term prognostic information than Medsger’s classes. Its reproducibility and ease of use make it a useful tool for the functional and prognostic evaluation of SSc patients at risk for or with ILD.Table:VariablesDiscovery (n=207)Replication (n=151)DcSSc62 (30%)98 (64%)Age at first PFR48.6±1249.1±14.4Disease duration at first PFR1.7±1.61.3±2.4FVC90.5±18.191.1±20.2DLco70.7±19.861.3±20.1ILD on HRCT179 (86%)125 (80%)Scl70157 (76%)153 (78%)SSA63 (30%)32 (21%)n of visits38571473Follow-up time, yrs11±5.610.6±5.7Deaths27 (13%)23 (15%)Disclosure of Interests:Alessandro Santaniello: None declared, Chiara Bellocchi: None declared, Luca Bettolini: None declared, Marcello Cassavia: None declared, Gaia Montanelli: None declared, Adriana Severino: None declared, Monica Caronni: None declared, Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Enrico De Lorenzis: None declared, Gerlando Natalello: None declared, Paolo Delvino: None declared, Claudio Tirelli: None declared, Lorenzo Cavagna: None declared, Giacomo De Luca Speakers bureau: SOBI, Novartis, Celgene, Pfizer, MSD, Silvia Laura Bosello: None declared, Lorenzo Beretta Grant/research support from: Pfizer

scholarly journals Genotype Heterogeneity in Accessions of a Winter Barley Core Collection Assessed on Postulated Specific Powdery Mildew Resistance Genes

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 513
Author(s):  
Antonín Dreiseitl
Keyword(s):  
Resistance Genes ◽  
Core Collection ◽  
Powdery Mildew Resistance ◽  
Gene Bank ◽  
Winter Barley ◽  
The Core ◽  
Genotype Identification ◽  
Environmentally Safe ◽  
Mla Locus ◽  
Resistance Tests

Gene bank accessions are necessary for implementing many research and breeding projects. However, a great number of accessions are contaminated or confused. If such accessions are used, the results obtained from these projects are inaccurate and non-reproducible. There are methods that allow almost perfect genotype identification; nevertheless, they are relatively recent and results cannot be compared with the characteristics of the original accessions. Growing resistant cultivars is an environmentally safe and cheap way of disease management and knowledge of diverse resistance genes and their combinations can be used to identify varieties and verify their authenticity and homogeneity. For this purpose, all 172 accessions of the core collection (CC) of the Czech winter barley (Hordeum vulgare) gene bank, originating from 35 countries, were studied. For resistance tests, 51 reference isolates of Blumeria graminis f. sp. Hordei, collected in all nonpolar continents over a period of 63 years and representing the global virulence/avirulence diversity of the pathogen, were used. Only 25 barley accessions were homogeneous (genetically uniform), whereas 147 accessions were heterogeneous due to presence of different genotypes. In total, 17 resistance genes were found singly or in combinations; 76.3% of accessions with identified resistance genes carried alleles at the Mla locus. To purify the CC, progenies of individual plants must be multiplied and authenticity and homogeneity of the seed should be confirmed with resistance tests, and subsequently can be studied with more advanced methods.

A Core Collection for the United States Annual Medicago Germplasm Collection

Crop Science ◽  
1994 ◽  
Vol 34 (1) ◽  
pp. 279-285 ◽  
Author(s):  
Noa Diwan ◽  
Gary R. Bauchan ◽  
Marla S. McIntosh
Keyword(s):  
United States ◽  
Core Collection ◽  
Germplasm Collection ◽  
The United States ◽  
Annual Medicago
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