2010 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). These cultivars represent a core collection of worldwide Vitis germplasm maintained at the USDA-ARS Vitis Clonal Repository in Davis, CA. The 36 polyphenolic compounds, were identified and quantified. Abundant variation was found for these groups of compounds. Briefly, the most abundant anthocyanins were Malvidin 3-O-glucoside and malvidin 3-O-(6-O-coumaryl)-glucoside, each accounting for about 32% of the total anthocyanins. Procyanidin B1 being the most abundant compound and accounting for 50% of the total variation in the group of flavaonls. Quercetin 3-O-glucuronide and quercetin 3-O-glucoside were the most abundant compounds in the group of flavonols. For the group of hydroxycinnamic acids, with caftaric acid being the most abundant compound and accounting for 73.7% of the total variation. 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. Positive correlations were found among these groups of compounds. As expected, these groups of compounds, all negatively correlated with berry weight. From these analyses, several cultivars with high contents of total and individual polyphenols were identified.
Also completed the HPLC analysis on more than 300 berry samples of wild Vitis species collected from the USDA-ARS Vitis Clonal Repository in Geneva, NY. Data analysis is in progress.
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.