RT Journal Article SR Electronic T1 The Effects of Hydrogen Cyanamide on Enhancing the Time and Amount of Budbreak in Young Grape Vineyards JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 47 OP 51 DO 10.5344/ajev.1989.40.1.47 VO 40 IS 1 A1 Asfaw Zelleke A1 W. Mark Kliewer YR 1989 UL http://www.ajevonline.org/content/40/1/47.abstract AB Dormant two-, three-, and four-year-old Thompson Seedless and Cabernet Sauvignon vines and two-year-old Grenache vines grown at the University of California, Davis, were treated with either 1% or 2% H2CN2 one day after pruning and compared to untreated control vines. The average number of days to initial budburst after treatment of dormant canes with H2CN2 was two to four days less (p < 0.05%) than untreated vines for two-year-old Thompson Seedless and four-year-old Cabernet Sauvignon vines. Hydrogen cyanamide at either 1% or 2% significantly increased the percentage budburst on the basal two-thirds portion of canes of all varieties and age groups. All portions of canes from four-year-old Cabernet Sauvignon vines treated with 2% H2CN2 had greater percentage budburst than control vines. Hydrogen cyanamide applied at a rate of 1% induced significantly (p < 0.05) greater percent budburst on two-year-old Grenache vines compared to a rate of 2%, whereas the latter treatment was most effective in inducing earlier budbreak on canes of Thompson Seedless and Cabernet Sauvignon vines.