'EarliGrande' peach [Prtmus persiea (L.) Balsch] trees were sprayed before
budbreak in the last week of Dec with 0.5, 1.0, 1.5, and 2.0 % Dorey 50 (hydrogen
cyanamide 49% wfw; HC) in two successive seasons (2000 & 2001). In the first
season. 2.5% HC was used and was excluded in the second season because of the
excessive thinning. Fruits were stereo at 2 or 4 °e and 60-85% RH. Fruits were
sampled al harvest (zero time) and at 10-day intervals up to 40 days. The objective
was to determine the effect of pre-bud break HC spray on peach (growing in Ismailia)
yield ami quality at harvest and after cold storage at different temperatures. In the first season, fruit number/tree decreased by HC treatments while thi'
average weight (in both seasons) of the individual fruit was increased. The comroi
fruit (no HC treatments) had the lowest fruit weight in both seasons. HC treatments at
1 5, 2.0 (in both seasons), and 2.5% (in the first season) revealed the highest (ruft
weigh!. He at high concentrations (1.5 - 2.5%) increased fruit length and diameter
over the control and lower HC concentrations. Also. fruit acidity and 'L' and -b: colour
values were maintained. However, SSC and 'a' colour values were increased by HC
treatments while firmness decreased by increasing HC concentration Storage at z'c resulted in a reduction in fruit weight loss, phenolic acids (%).
'a' colour value. and a higher fruit firmness than storage at 4°C. No differences were
noticed in fruit acidity, SSC, 'L' and 'b' colour values between storage at 2 or 4"C,
During storage for 40 days, weight loss, SSC, phenolic acids, and 'a' colour
values increased while fruit length, diameter, firmness, acidity, and 'b' colour values
were decreased. The combination of 2 or 2.5% HC and Irurt storage at 2°e resulted in a
reduction of weight loss (%) than using Ihe same HC concentrations and storage at
4'e. In addition. He treatments in combination with 2°C storage temperature resulted
in higher iruil firmness and SSC and a reduction in 'L' and '8' colour values than
Llsing the same HC concentrations and 4°e storage temperature in both seasons.