Single-node cuttings for budbreak phenotyping in grapevine

Budbreak is a critical stagein terms of vulnerability tospring frost, a major issue accentuated by the advancement of grapevine development due to global warming. Recognizing the determinants of budbreak regulation is essential to allow the selection, or generation, of genotypes better suited to dealwith a changing climate. Due to the practical difficulties and inherent variability in observing complexphenomena such as spring phenology in field, standardized alternatives are desirable. For these reasons, the potential of characterizingdormancy release using single-node cuttings was tested using cultivars Chardonnay and Cabernet Sauvignon, known for their different budburst timing in the field. Visual phenotyping was employed, in concert with Differential Thermal Analysis (DTA), to evaluate differences in deacclimation and dormancy release. The results confirmed that in field differences remain noticeable in single-node cuttings, corroboratedby macroscopic differences and different deacclimation kinetics. In conclusion, single-node cuttings candelineate inter-varietal differences in bud burst timing under standardized conditions and can be considered for use in screening activities.