Annona Species Monograph.pdf - Crops for the Future

Chapter 10. Agronomy
branches above 2.5 m height to avoid excessive growth and alternate yield,
and to promote better quality fruits. Pruning for rejuvenation is done in old
soursop orchards, where the semi-abandoned tall trees (Fig. 10-11 A) have
excessive branching with low yield capacity. All vertical branches are
eliminated including the thick lateral and terminal ones (Fig. 10-11 B), in
order to attain a plant height of 2.5-3.0 m, then training the new lateral
branches into horizontal positions at a later date (Fig. 10-11 C).
Figure 10-11. Pruning for rejuvenation of a soursop tree: A) canopy of
an old soursop tree before pruning; B) pruning of lateral and terminal
branches; C) training of lateral branches into horizontal positions.
Adapted from Torres and Sánchez (1992)
Pruning is not usually carried out on sugar apple trees in arid regions, except
to remove unproductive old branches (Singh, 1992). No information is
available for custard apple. Methods of pruning have not been worked out for
wild soursop, but the trees respond well to coppicing (FAO, 1988).
Pruning for plant production is very common in cherimoya and sugar apple
(Agustín and Alviter, 1996; Bonaventure, 1999). However, the literature does
not mention pruning for production in soursop (Torres and Sánchez, 1992;
Pinto and Ramos, 1997). The position of the bud may be the reason for this,
since soursop has its lateral buds in the leaf axil while cherimoya and sugar
have subpetiolar buds ('buried buds') in the base of the swollen leaf petiole
(Nakasone and Paull, 1998).
Leaf shed in cherimoya and sugar apple generally occurs prior to the
elongation of the 'buried buds', so that mechanical removal of leaves, by
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