Ling Huang, Patty Skinkis, James Osborne, Qin Zhou, Yanping Qian, and Michael Qian*
*Oregon State University, 3051 NW Campus Way, Corvallis, OR 97331 (michael.qian@oregonstate.edu)

Grapevine red blotch disease has a negative effect on the grape berry developing process and decreases sugar accumulation. Endogenous abscisic acid (ABA) is an im- portant plant growth regulator that triggers berry ripening. We examined the impact of exogenous ABA on red blotch-affected vines with regard to wine composition. ABA was sprayed on red blotch-affected grapevines around veraison, while control groups were left unsprayed. Total monomeric anthocyanin was determined with a spectrophotometer by the absorbance change of anthocyanin at different pH. Total phenolic content was analyzed using the Folin-Ciocalteu colorimetric method. Volatile profiles of wines made from grapes of the ABA trial were analyzed using headspace (HS)-GC-FID, stable isotope dilution approach with solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) and SBSE-GC-MS techniques. Compared to control, ABA treatment led to lower levels of total monomeric anthocyanin and total phenolic content in wines. ABA treatment had no significant effect on important volatile aroma compounds of wines.

Funding Support: Oregon State University