Percent budbreak and average days to budbreak (ADBB) for single-node cane segments repeatedly sampled from field-grown Cabernet Sauvignon (CS) and Chardonnay (CH) grapevines from July 2011 through Jan 2012. Percent budbreak was estimated after a 60-day exposure to day/night temperatures of 25/20°C with a 15-hr photoperiod. ADBB was calculated as:
, where ni is the number of buds that reached stage 4 or beyond within consecutive days, Di is the number of days elapsed since the beginning of the test, and N is total number of buds that reached stage 4 or beyond during the 60-days of the assay.