Agriculture Reference
In-Depth Information
Table 11.5.
Fruit and tree characteristics of
fi
ve Hawaiian cultivars. Data are
averages from tests con
ducted at three locations (winter harvest only).
Characteristics
Cultivar
Kapoho
Higgins
Line 8
Waimanalo
Sunrise
Height to
fi
rst
fl
ower
(cm)
147
97
169
76
91
Fruit weight (g)
343
367
516
695
425
Soluble solids (%)
15.7
15.9
15.0
15.2
14.5
Flesh colour
Yellow
Yellow
Yellow
Yellow
Red
Carpellodic fruit (%)
0
1.0
1.0
0.8
-
Other culls (%)
16
12
5
10
-
Marketable (kg/tree)
17
31
26
39
-
Phytophthora
resistance
a
I
S
R
R
I
Virus resistance
b
IT
HT
S
S
S
a
R = resistant; I = intermediate; S = susceptible.
b
HT = high tolerance; IT = intermediate tolerance; S = susceptible.
CULTURAL PRACTICES
Propagation
Papaya is almost entirely propagated from seeds in commercial cultivation.
Sound seeds usually germinate after 2 weeks in the polybags and are ready
to transplant at the 8-12-leaf stage, after about 6 weeks. The seeding rate for
papaya is very low as dry papaya seeds are light, weighing about 14.5 g per
1000 seeds. To establish a hectare of papaya, about 100 g of seed is required.
Approximately 100-150 g of seeds with 80% germination are needed to
produce the 2000 plants needed for one hectare.
Papaya seed can be harvested when the fruits reach 'colour break' stage.
Growers select trees with desirable characteristics, from which seeds, generally
from open-pollinated fruit, are saved. This seed produces uniform progenies
if from a single cultivar. The seeds are non-recalcitrant and can be dried to
moisture levels of 9-12% for long-term storage. Seeds harvested fresh from
fruit have very low and variable germination. Removal of the sarcotesta and
soaking in gibberellic acid promotes germination; uniformity of germination
is further enhanced by seed drying and cool-temperature storage at 15°C
for 30-50 days. Papaya seeds without the sarcotesta that are well-dried and
stored at 5°C retain 60-70% germination for 5 years (Chan and Tan, 1990).
Seeds may be sown in trays fi lled with a suitable medium, peat pots,
polyethylene bags or directly in the fi eld. Germination occurs in 12-20 days.
Seedlings are transplanted into 7.6 cm peat pots or into 10 cm plastic bags
