Annona Species Monograph.pdf - Crops for the Future

Chapter 10. Agronomy
commercial production, since it guarantees significantly higher production
and better fruit quality than open pollination. Cogez and Lyannaz (1996)
compared natural and hand pollination in two sugar apple cultivars: ‘Thai
Lup’ and ‘New Caledonia’. Natural pollination had 0% and 3.6% success in
‘Thai Lup’ and ‘New Caledonia’, respectively, while hand pollination
success was 100% in ‘Thai Lup’ and 90-93% in ‘New Caledonia’. When
intravarietal and intervarietal pollen was combined with hand pollination, the
success rate was 90.9% and 92.6% success, respectively, in New Caledonia.
Pinto and Ramos (1999) obtained 26% fruit set with natural pollination of
soursop in the Brazilian Cerrado conditions (Brazilian savannah), while fruit
set was 73% when hand pollination with a paint brush was used.
Allogamous hand pollination is also effective with cherimoya. Duarte and
Escobar (1998) applied self pollen on cherimoya cultivar Cumbe in El
Zamorano, Honduras, as well as cultivar Bronceada, in the morning (6-8 h)
and in the late afternoon (16-18 h). The highest fruit set (46.4%) was
obtained with cross pollen, as compared with 30.3% and 23.1% with self
pollen applied in the morning and in the afternoon, respectively. Fruit set was
also better at the beginning of the flowering period.
The success of hand pollination depends on the technique, as well as the
species and conditions. Economically effective hand pollination of
cherimoya was carried out for the first time in California by Dr. Schroeder in
1941 (Grossberger, 1999) and to date the technique has varied little. Several
authors (Agustín and Alviter, 1996; Mansour, 1997; Bonaventure, 1999;
Grossberger, 1999) have described the hand pollination technique as follows.
The cherimoya flowers that will serve as the pollen source are gathered and
held in a small paper bag until the pollen is shed. The operator should
remove the 3 petals of the external whorl of freshly opened flowers that will
be pollinated. The 3 petals of the internal whorl are then held open with one
hand, while, with the other, the pollen is applied onto the pistils with a small
camel hair brush, using several back and forth strokes. Pollen can also be
blown onto the pistils with special blowers (e.g., the Aluminum Hand
Blower, Technes Industry, São Paulo, Brazil; Bonaventure, 1999). A small
cylindrical plastic container (such as those used for rolls of film: Plate 3) is
an important tool used by soursop growers of the Brazilian Cerrados to carry
pollen, which can be kept in the operator's shirt pocket (Plate 5), leaving the
grower's hands free to execute the hand pollination.
Hand pollination of cherimoya is generally practiced in the morning or the
afternoon as it is too warm and dry at midday and a lower fruit set is obtained
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