Agriculture Reference
In-Depth Information
40
Thailand (max.)
30
Australia (max.)
Thailand (min.)
20
Spain (max.)
Australia (min.)
10
Spain (min.)
0
JFMA
MJJ
Month
ASOND
Fig. 6.3.
Seasonal changes in mean monthly minimum temperature for areas suited
to sweetsop (Bangkok, Thailand), atemoya (Mareeba, Australia) and cherimoya
(Malaga, Spain) in southern-hemisphere equivalents (after Marler
et al.
, 1994).
the end of winter and the beginning of spring, during which many leaves
fall, followed by fl owering by the end of spring. In areas with year-round good
growing temperatures and no dry period, atemoyas can be forced to complete
their fl owering and fruit cycle in 8 months. An 8-month fruit cycle allows for
three harvests in 2 years. To achieve three cycles in 2 years requires careful
management of irrigation, fertilization, pruning and defoliation.
Poor pollination is a frequent problem with all three species and
occurs under high temperature (30°C) and low humidity (30% RH).
Lower temperature (25°C) and high humidity (80% RH) greatly improves
pollination. Hand-pollination is recommended for cherimoya and atemoya to
achieve more uniform fruit shape (Fig. 6.4). Sweetsop exposed to >30°C and
relative humidity <60% leads to poor pollination, even if hand-pollinated.
At 25°C and a relative humidity >80% sweetsop pollination is greatly
improved, with too high RH and rain negatively af ecting anther dehiscence.
High temperatures will induce strong vegetative growth in atemoya and
cherimoya. A temperature of 22-28°C is ideal for fruit set in atemoya, while
cherimoya needs slightly lower temperatures for fruit set.
