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

GONZÁLEZ ANTIVILO, FRANCISCO ALBERTO; PAZ ROSALIA CRISTINA; MARKUS KELLER; ROBERTO BORGO; JORGE TOGNETTI; FIDEL ROIG JUÑENT

INTERNATIONAL JOURNAL OF BIOMETEOROLOGY

SPRINGER

Lugar: Berlin; Año: 2017 vol. 61 p. 2033 - 2045

0020-7128

Low temperature is a limiting factor that affects vineyard distribution globally. The levelof cold hardiness acquired during the dormant season by Vitis sp. is crucial for wintersurvival. Most research published on this topic has been generated beyond 40° Nlatitude, where daily mean temperatures may attain injurious levels during the dormantseason resulting in significant damage to vines and buds. Symptoms of cold injuryhave been identified in Mendoza (32-35° S latitude), a Southern Hemisphere wineregion characterized by a high thermal amplitude, and warm winds during the dormantseason. These symptoms have usually been attributed to drought and/or pathogens,but not to rapid deacclimation followed by injurious low temperatures. Because localinformation on meteorological events as probable causes is scarce, this research wasdesigned to test and study this assumption by comparing macro-, meso-, andmicroclimatice data from Mendoza, Argentina and eastern Washington, USA. The goalwas to unveil why freezing damage has occurred in both regions, despite the existenceof large climatic differences. Because environmental parameters under field conditionsmay not correspond to data recorded by conventional weather stations, sensors wereinstalled in vineyards for comparison. Microclimatic conditions on grapevines were alsoevaluated to assess the most vulnerable portions of field-grown grapevines. In order tobetter understand if it may be possible to modify cold hardiness status in a short period with high thermal amplitude conditions, deacclimation was induced using a thermaltreatment. Hence, despite the fact that Mendoza is warmer, and temperatures are notas extreme as in Washington, high daily thermal amplitude might be partially involvedin plant deacclimation, leading to a differential cold hardiness response.