Macro- and microclimate conditions may alter grapevine deacclimation: variation in thermal amplitude in two contrasting wine regions from North and South America

ANTIVILO, FRANCISCO GONZALEZ; PAZ, ROSALÍA CRISTINA; KELLER, MARKUS; BORGO, ROBERTO; TOGNETTI, JORGE; JUÑENT, FIDEL ROIG

INTERNATIONAL JOURNAL OF BIOMETEOROLOGY

SPRINGER

Lugar: Berlin; Año: 2017

0020-7128

Low temperature is a limiting factor that affectsvineyard distribution globally. The level of cold hardinessacquired during the dormant season by Vitis sp. is crucial forwinter survival. Most research published on this topic hasbeen generated beyond 40° N latitude, where daily mean tem-peratures may attain injurious levels during the dormant sea-son resulting in significant damage to vines and buds.Symptoms of cold injury have been identified in Mendoza(32?35° S latitude), a Southern Hemisphere wine region char-acterized by a high thermal amplitude, and warm winds duringthe dormant season. These symptoms have usually been at-tributed to drought and/or pathogens, but not to rapiddeacclimation followed by injurious low temperatures. Because local information on meteorological events as prob-able causes is scarce, this research was designed to test andstudy this assumption by comparing macro-, meso-, and mi-croclimatic data from Mendoza, Argentina, and easternWashington, USA. The goal was to unveil why freezing dam-age has occurred in both regions, despite the existence of largeclimatic differences. Because environmental parameters underfield conditions may not correspond to data recorded by con-ventional weather stations, sensors were installed in vineyardsfor comparison. Microclimatic conditions on grapevines werealso evaluated to assess the most vulnerable portions of field-grown grapevines. In order to better understand if it may bepossible to modify cold hardiness status in a short period withhigh thermal amplitude conditions, deacclimation was in-duced using a thermal treatment. Hence, despite the fact thatMendoza is warmer, and temperatures are not as extreme as inWashington, high daily thermal amplitude might be partiallyinvolved in plant deacclimation, leading to a differential coldhardiness response.