Chilling requirements and dormancy evolution in grapevine buds

Abstract

Fluctuations in winter chilling availability impact bud dormancy and budburst. The objective of this work was to determine chilling requirements to induce and overcome endodormancy (dormancy controlled by chilling) of buds in different grape cultivars. ‘Chardonnay’, ‘Merlot’ and ‘Cabernet Sauvignon’ shoots were collected in Veranópolis-RS vineyards in 2010, and submitted to a constant 3 °C temperature or daily cycles of 3/15 °C for 12/12h or 18/6h, until reaching 1120 chilling hours (CH, sum of hours with temperature ≤ 7.2 °C). Periodically, part of the samples in each treatment was transferred to 25 °C for budburst evaluation (green tip). Chilling requirements to induce and overcome endodormancy vary among cultivars, reaching a total of 136 CH for ‘Chardonnay’, 298 CH for ‘Merlot’ and 392 CH for ‘Cabernet Sauvignon’. Of these, approximately 39, 53 and 91 CH are required for induction of endodormancy in the three cultivars, respectively. The thermal regimes tested (constant or alternating) do not influence the response pattern of each cultivar to cold, with 15 °C being inert in the CH accumulation process. In addition, time required to start budburst reduces with the increase in CH, at a rate of one day per 62 CH, without significant impacts on budburst uniformity.

Cold Hardiness Dynamics and Spring Phenology: Climate-Driven Changes and New Molecular Insights Into Grapevine Adaptive Potential

“…Cold acclimation is a process in which physiological, biochemical, and epigenetic changes driven by cold temperatures confer freezing tolerance ( Wisniewski et al, 2018 ). Exposure to chilling temperatures, with difference depending on cultivar ( Anzanello et al, 2018 ), is required to resume bud responsiveness to environmental signals and avoid growth start if mild temperatures occur during winter ( Rohde and Bhalerao, 2007 ). Internal signals also prevent growth resumption in late summer or early autumn, which would cause the death of the bud in unfavorable environmental conditions ( Lang et al, 1987 ; Horvath et al, 2003 ).…”

Alternative budburst management in Campanha Gaúcha vineyards

“…Grapevines require a chilling exposure, depending on genotype, ranging between 50 and 400 chilling hours (CH, sum of hours with air temperature below 7.2°C) for normal budburst (TREJO-MARTÍNEZ et al, 2009). 'Merlo' (Vitis vinifera L.) is a cultivar that demands an average of 300 CH during the winter period to overcome bud endodormancy (ANZANELLO et al, 2018). The average number of CH from May to September in Santana do Livramento varied from 340 CH, based on a 1966-2003 data series (MATZENAUER et al, 2005), to 364 CH, based on a 1981-2010 data series (ALVES et al, 2019).…”

Controle de gemas laterais sobre a evolução da dormência de gemas apicais em macieira

“…Um exemplo clássico é a ação inibitória em que o ápice exerce efeito sobre a brotação das gemas laterais durante as fases do ciclo vegetativo (Cook e Jacobs, 1999). A suspensão do crescimento da gema pode também ser dada pela endodormência e ecodormência (Anzanello et al, 2018).…”