2011 Annual Report
1a.Objectives (from AD-416)
The objective of this research is to characterize trait variation of the USDA-ARS Vitis germplasm collections. The phenotypic trait information collected from this study, in combination with the genotypic information generated from the grape SNP discovery project led by Dr. Ed Buckler at ARS, will significantly advance our knowledge and capability in identifying useful allelic variation in the Vitis germplasm for grape improvement. In addition, one mapping population relevant to winegrape breeding will also be characterized to examine how well the research results of trait variation from Vitis germplasm can be extended to practical breeding material.
1b.Approach (from AD-416)
Phenotype USDA-ARS Vitis germplasm collections:
1. Phenotyping berry shape, berry color, berry length and width, and cluster size per Standard Biodiversity International Descriptors for all non-hybrid Vitis germplasm accessions (about 700) from the USDA-ARS Geneva Vitis Clonal Repository. This work will be closely coordinated with the ongoing phenotyping effort at the USDA-ARS Davis Vitis Clonal Repository and the ARS grape SNP discovery project of Dr. Ed Buckler et al.
2. Analyzing key primary and secondary metabolites of 600 Vitis germplasm accessions from the USDA-ARS Vitis Clonal Repositories at Davis, CA and Geneva, NY. A total of 3,600 samples (3 replicates x 2 years x 600 accessions) will be analyzed.
Phenotype one mapping population relevant to winegrape breeding:
1. Analyzing key primary and secondary metabolites of the Horizon x Illinois 547-1 mapping population developed by Dr. Bruce Reisch at Cornell. A total of 400 samples (2 replicates x 2 years x 100 lines) will be analyzed.
Analyze phenotypic data and carry out marker-trait association analysis:
1. Characterizing properties of the phenotypic trait variation investigated.
2. Collaborating with Dr. Ed Buckler and his group to carry out marker-trait association analysis.
3. Validating association analysis results with linkage mapping data.
Evaluated the profiles of 36 polyphenolic compounds in the ripe berry samples of 344 European grape (Vitis vinifera) cultivars for two successive years (2008 and 2009 seasons). These cultivars represent a core collection of worldwide Vitis germplasm maintained at the USDA-ARS Vitis Clonal Repository in Davis of California, USA. The 36 polyphenolic compounds, including 16 anthocyanins, 6 flavonols and 6 flavanols, 6 hydroxycinnamic acids, and 2 hydroxybenzoic acids, were identified via HPLC-MS and quantified by HPLC-DAD. In general, wine grapes had higher concentrations than table grapes for all of these compounds except for hydroxycinnamic acids for which no significant differences were found between wine and table grapes. Berry colors affected the total contents of anthocyanins, but had no apparent impacts on other groups of compounds. The relative abundances of these five groups of compounds are in the order of anthocyanins, flavaonls, flavonols, hydroxycinnamic acids, and hydroxybenzoic acids which explained 52.1%, 23.3%, 5%, 17.6% and 2% of the total phenolic variation, respectively. From these analyses, several cultivars with high contents of total and individual polyphenols were identified.
Characterized the polyphenolic composition and content in the ripe berries of 147 grape accessions representing 16 Vitis species maintained in the USDA-ARS Vitis Clonal Repository in Geneva, New York. A total of 48 polyphenolic compounds, including 28 anthocyanins, 6 flavonols, 6 flavanols, 6 hydroxycinnamic acids, and 2 hydroxybenzoic acids, were identified. The wild grape species had unique presence of abundant di-glucoside derivatives of anthocyanins which were predominantly nonacylated. The mean contents for anthocyanins, flavanols, flavonols, hydroxycinnamic acids, and hydroxybenzoic acids in the wild species were about 2 to 10 folds higher than their respective counterparts in the most widely cultivated grape species V. vinifera.
This research will provide an assessment of the range of variation of the important grape polyphenols in the USDA Vitis germplasm, which will in turn accelerate the development of grape varieties with superior fruit quality.
The project progress has been closely monitored through regular meetings, updates, and site visits. Research plans and activities are being reviewed on a regular basis.