Natural Product Phenolic Diglycosides Created from Wildfires, Defining Their Impact on California and Oregon Grapes and Wines.

Forest fires produce malodorous phenols, bioaccumulated in grapes as odorless phenol glycosides (mono- to tri-), and produce unpleasant smoke tainted wines when these complexes are transformed by glycosidases in saliva. Metabolomic analyses were used to further understand smoke taint by quantitating marker phenolic diglycosides via UHPLC separations and MS/MS multiple reaction monitoring. A collection of grapes and wines provided data to forecast wine quality of grapes subjected to wildfire smoke infestations; the analytics used a panel of reference compounds (1-6). Overall, eight different Vitis vinifera varietals were examined from 2017-2021 vintages involving >218 distinct samples (wines and/or grapes) from 21 different American Viticulture Areas. Results acquired allowed correlation of phenolic diglycoside levels as a function of grape cultivar, varietal clones, and intensity of wildfire smoke. Baseline data were tabulated for nonsmoked samples (especially, Cabernet Sauvignon having a sum 1-6 of <6 µg/L) and then compared to those exposed to six other levels of smoke. Outcomes established that (1) analyzing paired samples (bottled wines versus smoke-exposed grapes) can provide diagnostic metabolomic data, (2) phenolic diglycosides are stable in wines aged for >2.5 years, and (3) major gaps exist in our current understanding of this pool of metabolites.

Assessment of carbon in woody plants and soil across a vineyard-woodland landscape.

BACKGROUND: Quantification of ecosystem services, such as carbon (C) storage, can demonstrate the benefits of managing for both production and habitat conservation in agricultural landscapes. In this study, we evaluated C stocks and woody plant diversity across vineyard blocks and adjoining woodland ecosystems (wildlands) for an organic vineyard in northern California. Carbon was measured in soil from 44 one m deep pits, and in aboveground woody biomass from 93 vegetation plots. These data were combined with physical landscape variables to model C stocks using a geographic information system and multivariate linear regression. RESULTS: Field data showed wildlands to be heterogeneous in both C stocks and woody tree diversity, reflecting the mosaic of several different vegetation types, and storing on average 36.8 Mg C/ha in aboveground woody biomass and 89.3 Mg C/ha in soil. Not surprisingly, vineyard blocks showed less variation in above- and belowground C, with an average of 3.0 and 84.1 Mg C/ha, respectively. CONCLUSIONS: This research demonstrates that vineyards managed with practices that conserve some fraction of adjoining wildlands yield benefits for increasing overall C stocks and species and habitat diversity in integrated agricultural landscapes. For such complex landscapes, high resolution spatial modeling is challenging and requires accurate characterization of the landscape by vegetation type, physical structure, sufficient sampling, and allometric equations that relate tree species to each landscape. Geographic information systems and remote sensing techniques are useful for integrating the above variables into an analysis platform to estimate C stocks in these working landscapes, thereby helping land managers qualify for greenhouse gas mitigation credits. Carbon policy in California, however, shows a lack of focus on C stocks compared to emissions, and on agriculture compared to other sectors. Correcting these policy shortcomings could create incentives for ecosystem service provision, including C storage, as well as encourage better farm stewardship and habitat conservation.

Effect of Fenarimol Application Timing on Fruit Shape of Bartlett Pear.

Plots were established at Ukiah and Davis, California, and Medford and Hood River, Oregon, to evaluate the effect of fenarimol (Rubigan 1 EC), applied at various stages of bloom development, on fruit shape of Bartlett pear. At each location, 10 different treatment schedules were applied at various combinations of bud burst (BB), green cluster (GC), white bud (WB), and full bloom (FB). In schedules that included an application at FB, the fruit length:diameter (L/D) ratio was significantly reduced in at least three of four locations when compared to untreated controls. When fenarimol was applied at BB, GC, WB, and FB, the L/D ratio was reduced at all locations. Treatment at BB only did not affect L/D ratio. Schedules involving GC or WB, but not FB, resulted in reduced L/D ratios at only one or two locations. When data from all four locations were combined, L/D ratios were significantly reduced by all fenarimol treatments except BB alone, and the smallest L/D ratios resulted from treatments which included applications at both WB and FB. Fruit stem length was significantly reduced by all timings of fenarimol application except GC at Medford, and all timings except BB and GC at Ukiah. Fruit weight did not differ among treatments.