Agriculture Reference
In-Depth Information
GENERAL CHARACTERISTICS
Flowers
The fl owers of
Annona
species are hermaphroditic and are produced singly
or in small clusters in a compound infl orescence on an enlarged receptacle.
Flowers arise on the current season's growth and occasionally on old wood.
Cherimoya and atemoya fl owers are fragrant and are solitary or in groups of
two or three on short, hairy stalks. The fl owers are multi-staminate and multi-
pistilate. New fl owers continue to appear towards the apex of the shoot as
fl owers produced earlier at the basal portions mature (Fig. 6.5). Defoliation of
cherimoya or atemoya
manually or by using ethephon spray promotes lateral
branch growth and induces additional fl ower formation, since it exposes the
buds covered by the petiole base.
Annona
species generally require 27-35 days for fl ower-bud development
from initiation to anthesis. Dif erences in fl oral behaviour in the various
areas may be attributed to both genetic variability and climatic dif erences
(Kshirsaga
et al.
,
1976). Flowering can extend from 3 to 6 months or even
longer, with heavy peaks. In sweetsop, two major fl owering periods occur after
periods of vegetative fl ushes, with the second peak coinciding with the onset of
the monsoon in India (Kumar
et al.
,
1977). Atemoyas in Australia produce the
25
80
20
60
Flowers set
15
40
10
Flowers
20
5
Shoot
0
0
0
2
4 6 8
Weeks from the start of bud break
10
12
14
Fig. 6.5.
Atemoya: newly emerging vegetative-
fl
ush shoot increment, total number
of
fl
owers produced per week and percentage
fl
owers set per week. Peak fruit set
occurs after completion of vegetative
fl
ush (after George and Nissen, 1988).
