ANNONAS: CHERIMOYA, ATEMOYA AND SWEETSOP - Tropical Fruits - page 137

Clonal propagation by cuttings, layering, inarching, grafting and budding
have been tried (Table 6.2). Inconsistent results have been obtained with
cherimoya when 1-year-old cuttings are treated with rooting hormones, and
cuttings from mature trees have been dii cult to root (Duarte et al. , 1974b).
Atemoya, as a hybrid, has to be propagated asexually by cuttings from selected
trees or grafting or budding. There are cultivar dif erences in the rooting ability
of atemoya, with 'African Pride' having a higher rooting response (60-80%)
than 'Pink's Mammoth' and cherimoya (<20%). Atemoya tip cuttings are
superior to stem cuttings, with rooting percentages between 50 and 60%,
as compared with about 25% for stem cuttings (Sanewski, 1991). Time of
cutting removal is crucial for success, cuttings taken at the end of the cool
season showing the greater success. Roots should occur in 8-12 weeks and
the cuttings are ready to pot in 16-20 weeks. Air-layering can be used with
some cultivars, although cherimoya is not propagated easily. A modifi cation
where the new shoot is clamped and only the shoot tip is exposed is successful.
Inarching of A. squamosa , A. cherimola , A. glabra and atemoya to A. reticulata
rootstock has been successful, with only A. glabra giving less than 70% success.
Although inarching has given good results, it is time-consuming and costly for
large-scale propagation (George and Nissen, 1987b).
Cherimoyas are normally grafted or budded. Grafting is superior to budding
in percentage takes and subsequent growth, with side-whip graft and cleft-
graft techniques giving the best results (Duarte et al. , 1974b). The branches
should be defoliated 1-2 weeks before scion wood is cut to induce bud swelling.
T-budding and chip-budding methods are successful. There are considerable
graft incompatibilities among Annona (Table 6.3) and Rollinia species and types.
Cherimoya has been found to be a vigorous rootstock for 'Pink's Mammoth'
(atemoya), although atemoya is not compatible with A. glabra , A. montana ,

Table 6.2. Propagation methods and success for Annona spp. (after George and
Nissen, 1987b). Root-cutting success rate is unknown.
Method Species

Atemoya Sweetsop Cherimoya

Seedling
Genetically Variable Uniform Variable

Use Not recommended Good Rootstock

Tip and stem cutting Some cvs only Some cvs only Not successful

Micropropagation Possibly high Unknown Unknown

Layering Unknown High if modi fi ed

techniques used

Unknown

Air-layering <5% <5%

< 8.3%

Budding >70% >70% >70%

Grafting >70% >70% >70%