Agriculture Reference
In-Depth Information
covered with conical or rounded protuberances. The mature fruit is soft and
can easily be opened to show its white, juicy fl esh, of pleasing aroma and
subacid fl avour, containing numerous - sometimes few - brown or black, hard
and glossy, bean-like seeds. Atemoya has smaller seeds, while sweetsop has the
largest seed number.
Fruit growth shows the typical sigmoidal curve, with maturation
occurring in 16-24 weeks, depending upon species and growing conditions
(Fig. 6.6). Low humidity (<60% RH) and temperature (<13°C) near fruit
maturity can increase the severity of fruit skin russeting, as well as delaying
fruit maturation. High temperature can cause premature fruit ripening and
fermentation of the fruit.
CULTIVAR DEVELOPMENT
Genetics, cytogenetics and breeding
The chromosome numbers of
A. cherimola
,
A. reticulata
,
A. squamosa
and
atemoya are 2n = 14.
A. glabra
has been shown to be a tetraploid (2n = 28),
Weeks from anthesis
Fig. 6.6.
Increase in fruit diameter from anthesis for sweetsop and cherimoyas (after
Thakur and Singh, 1965).
