title: Impedance of the grape berry cuticle as a novel phenotypic trait to estimate resistance to Botrytis cinerea.
abstract: Warm and moist weather conditions during berry ripening provoke Botrytis cinerea (B. cinerea) causing notable bunch rot on susceptible grapevines with the effect of reduced yield and wine quality. Resistance donors of genetic loci to increase B. cinerea resistance are widely unknown. Promising traits of resistance are represented by physical features like the thickness and permeability of the grape berry cuticle. Sensor-based phenotyping methods or genetic markers are rare for such traits. In the present study, the simple-to-handle I-sensor was developed. The sensor enables the fast and reliable measurement of electrical impedance of the grape berry cuticles and its epicuticular waxes (CW). Statistical experiments revealed highly significant correlations between relative impedance of CW and the resistance of grapevines to B. cinerea. Thus, the relative impedance Zrel of CW was identified as the most important phenotypic factor with regard to the prediction of grapevine resistance to B. cinerea. An ordinal logistic regression analysis revealed a R2McFadden of 0.37 and confirmed the application of Zrel of CW for the prediction of bunch infection and in this way as novel phenotyping trait. Applying the I-sensor, a preliminary QTL region was identified indicating that the novel phenotypic trait is as well a valuable tool for genetic analyses.
authors.affiliation: Julius Kühn-Institut-Federal Research Centre of Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, Siebeldingen 76833, Germany. Katja.herzog@jki.bund.de.
authors.forename: Katja
authors.initials: K
authors.lastname: Herzog
authors.affiliation: Julius Kühn-Institut-Federal Research Centre of Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, Siebeldingen 76833, Germany. rolf.wind@kdwelt.de.
authors.forename: Rolf
authors.initials: R
authors.lastname: Wind
authors.affiliation: Julius Kühn-Institut-Federal Research Centre of Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, Siebeldingen 76833, Germany. reinhard.toepfer@jki.bund.de.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Töpfer
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D020171:Botrytis / Q000472:pathogenicity*; D060467:Disease Resistance; D017097:Electric Impedance; D005638:Fruit / Q000737:chemistry* / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D010641:Phenotype; D010935:Plant Diseases; D040641:Quantitative Trait Loci / Q000235:genetics; D015203:Reproducibility of Results; D027843:Vitis / Q000737:chemistry* / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D014885:Waxes
chemical_list: D014885:Waxes
keywords: Vitis vinifera; berry skin; bunch compactness; grapevine breeding; objective data; phenotyping; sensor development