Abscisic acid treatment to avoid late spring frosts damage during ‘Chardonnay’ vines budbreak

Abstract

The production of early budbreak Vitis vinifera L. cultivars in southern Brazilian highlands has been limited by the occurrence of late spring frosts. This study aimed to evaluate the abscisic acid (ABA) application on different dates to delay 'Chardonnay' vines budbreak, avoiding periods of greatest probability of frost occurrence. Experiments were carried out in a commercial vineyard, in Sao Joaquim, Santa Catarina, Brazil, at 1,270 m a.s.l., 1,270 m altitude, 28°14'51”S, 49°57'42”W, in two cycles. Five ABA concentrations were adopted on each cycle, ranging from 0 to 2000 mg L-1 and applications were made on the traditional date of pruning, which in this area represents the time when budbreak starts on shoots' apical buds, and two anticipated dates up to thirty days from this last. ABA was incorporated into lanolin and the resulting ointment was applied on the top of pruned shoots. On 2012/2013 cycle, vines treated 22 days before traditional date of pruning (DBP) sprouted in 29 days after treatment (DAT), while those treated on traditional pruning date sprouted in 18 DAT. The maximum delay observed with ABA comparing to control was four days. Treatments applied 30 DBP on 2013/2014 cycle resulted in sprouting in 37 DAT, while treatments applied on traditional pruning date, in 15 DAT. Control vines sprouted in 25 DAT and those treated with 2000 mg L-1 ABA in 28 DAT, delaying budbreak by three days. The latest pruning date and the highest ABA concentration (2000 mg L-1) presented better effect on vine budbreak delay. Changes were in general more expressively caused by the change in application dates. There were no problems with non-broken buds and the production was only slightly changed by ABA treatments. ABA application through this methodology was little effective on delaying grapevines budbreak and is not recommended for commercial use.