U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Northeast Area Geneva, New York Grape Genetics Research Unit (GGRU) Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            GEE, CHRISTOPHER - CORNELL UNIVERSITYitem
                                            GADOURY, DAVID - CORNELL UNIVERSITYitem
                                            Cadle-Davidson, Lance
  Submitted to: Plant Disease
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 2/17/2008
                                    Publication  Date: 7/1/2008
                                    Citation: Gee, C., Gadoury, D., Cadle Davidson, L.E. 2008. Ontogenic resistance to Uncinula necator varies by genotype and tissue type in a diverse collection of Vitis spp. Plant Disease. 92:1067-1073.Interpretive Summary: As plants or plant tissues age, their susceptibility to pathogens changes via a phenomenon known as ontogenic resistance.  Grapevine berries susceptible to grapevine powdery mildew become ontogenically resistant approximately 2 to 3 weeks post-bloom, as demonstrated in several cultivars of Vitis vinifera and in V. labruscana ‘Concord.’  To identify genetic variation for ontogenic resistance, we screened a diverse collection of species and interspecific hybrids maintained in the USDA-ARS cold-hardy Vitis germplasm collection in Geneva, NY.  Of the 79 genotypes whose fruit clusters were screened for susceptibility to powdery mildew under field conditions, 50 were resistant to powdery mildew irrespective of the stage of berry development at the time of inoculation.  Of the susceptible genotypes, 23 exhibited a statistically significant gain of ontogenic resistance as berries aged.  These 23 genotypes with ontogenic resistance included four species as well as several interspecific hybrids of Vitis spp.  Typically, ontogenic resistance functioned by reducing the frequency of successful penetration by U. necator.  Some genotypes developed ontogenic resistance earlier or later than most.  Ontogenic resistance ratings of the rachis and pedicels did not match those for the berries for the majority of genotypes studied.  Despite the broad conservation of the presence of ontogenic resistance, one genotype (V. rupestris ‘R-65-44’) remained persistently susceptible well past the onset of ripening, over one month later than reported previously for V. vinifera and V. labruscana.  The genetic variation identified in ontogenic resistance could facilitate further study of ontogenic resistance through characterization of new genetic resources.
                                Technical Abstract: Berries of grapevine (Vitis spp.) have a limited window of susceptibility to Uncinula necator, the causal agent of grapevine powdery mildew, corresponding to approximately 2 to 3 weeks post-bloom.  This phenomenon has been demonstrated in several cultivars of V. vinifera and in V. labruscana ‘Concord’, which all exhibited a similar temporal distribution of susceptibility.  To identify novel genetic variation for ontogenic resistance, we screened a diverse collection of species and interspecific hybrids maintained in the USDA-ARS cold-hardy Vitis germplasm collection in Geneva, NY.  Of the 79 genotypes whose fruit clusters were screened for susceptibility to powdery mildew under field conditions, 50 exhibited a high basal level of resistance to powdery mildew and did not develop more than trace levels of disease when inoculated, irrespective of the stage of berry development at the time of inoculation.  Twenty-three genotypes exhibited a statistically significant gain of resistance as berries aged.  This ontogenic resistance was conserved across four species and several interspecific hybrids of Vitis spp., though the timing of the onset of ontogenic resistance varied by genotype.  The mechanism of ontogenic resistance was assayed for three of the genotypes and reduced the frequency of successful penetration by U. necator on each.  Despite the broad conservation of ontogenic resistance across species, one genotype (V. rupestris ‘R-65-44’) remained susceptible past the onset of ripening, over one month later than reported previously for V. vinifera and V. labruscana.  Variation in the resistance phenotype was observed between the rachis, pedicels and berries within clusters of the majority of genotypes studied.  The multiple facets of genetic variation identified in ontogenic resistance could facilitate further study of the inheritance and molecular basis of ontogenic resistance.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov