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

MARKUS KELLER; FIDEL ALEJANDRO ROIG; ROSALIA CRISTINA PAZ; JORGE TOGNETTI; FRANCISCO GONZALEZ ANTIVILO; ROBERTO BORGO

INTERNATIONAL JOURNAL OF BIOMETEOROLOGY

SPRINGER

Lugar: Berlin; Año: 2017

0020-7128

Lowtemperature is a limiting factor that affects vineyard distributionglobally.  The level of cold hardinessacquired during the dormant season by Vitis sp. is crucial for winter survival.Most research published on this topic has been generated beyond 40° N latitude,where daily mean temperatures may attain injurious levels during the dormantseason resulting in significant damage to vines and buds. Symptoms of coldinjury have been identified in Mendoza (32-35° S latitude), a SouthernHemisphere wine region characterized by a high thermal amplitude, and warmwinds during the dormant season. These symptoms have usually been attributed todrought and/or pathogens, but not to rapid deacclimation followed by injuriouslow temperaturs. Because local information on meteorological events as probablecauses is scarce, this research was designed to test and study this assumptionby comparing macro-, meso-, and microclimatie data from Mendoza, Argentina andeastern Washington, USA. The goal was to unveil why freezing damage hasoccurred in both regions, despite the existence of large climatic differences.Because environmental parameters under field conditions may not correspond todata recorded by conventional weather stations, sensors were installed in  vineyards for comparison. Microclimaticconditions on grapevines were also evaluated to assess the most vulnerableportions of field-grown grapevines. In order to better understand if it may bepossible to modify cold hardiness status in a short period with high thermalamplitude conditions, deacclimation was induced using a thermal treatment.Hence, despite the fact that Mendoza is warmer, and temperatures are not asextreme as in Washington, high daily thermal amplitude might be partiallyinvolved in plant deacclimation, leading to a differential cold hardinessresponse.