Abstract
The polyamines Spermidine at 10-4
M, Putrescine at 10-3
M and 10-4
M, Spermine at 10-4
M and
aminoxyacetic acid at 500 ppm were applied, at full bloom to whole trees or branches of Fuerte,
in a young six year-old avocado orchard in the area of Chania Crete to increase fruit-set. In other
trials Fuerte trees were sprayed with GA3 at 50, 100, 200, 400 ppm and 100 ppm applied four
times at regular 10-day intervals. Further a mixture of 200 ppm GA3 25 ppm BAP
(benzylaminopurine) and 10 ppm NAA (naphthaleneacetic acid) was applied to young trees of
the cvs Hass and Fuerte.
As it was found gibberellic acid (50-400) ppm applied on Fuerte at full bloom increased
parthenocarpic fruits 40 to 80 times while four repeated, at weekly intervals, sprays of 100 ppm
of gibberellic acid increased parthenocarpic fruits more than 200 times. A mixture of 25 ppm
BAP plus 10 ppm of NAA and 200 ppm GA sprayed at bloom induced the setting of
parthenocarpic fruits in both Hass and Fuerte. Sper- midine or Spermine at 10-4
M or 10-3
M of
Putrescine sprayed at bloom increased fruit- set in Fuerte.
Additional index words: hormones, fruit drop, parthenocarpic fruits