J. Carreno et al., The effects of hydrogen cyanamide on budburst and fruit maturity of 'Thompson Seedless' grapevine, J HORT SCI, 74(4), 1999, pp. 426-429
The effect of hydrogen cyanamide (H2CN2) on budburst and fruit maturity of
'Thompson Seedless' grapes was examined. Nine year old vines of cv. Thompso
n Seedless grafted on R.110 rootstock and supported on overhead tendone tre
llis (parral), were treated with either 2% or 4% of H2CN2, 53 and 67 d befo
re expected budbreak and compared with unsprayed vines. The earliest treatm
ent with 4% H2CN2 enhanced budbreak and advanced fruit maturity by 17 d. Ho
wever, the same concentration applied 53 d before natural budbreak advanced
the date of maturity by only 4 d. All the treatments increased significant
ly the percentage of budburst compared with the control. H2CN2 had no signi
ficant effect on yield, but a positive effect on fruit quality. A higher in
dex of maturity was obtained by the treatment: 4% H2CN2, 67 d before budbre
ak. All the treatments of H2CN2 induced more uniform budburst compared with
the control. The best uniformity was obtained by the earliest spray using
the higher concentration (3%).