GROWING MELONS ON TREES 
The Papaya an Important Tropical Fruit Which Offers Great Opportunities to 
Breeders—Remarkable Irregularities in Sex—Changing Male 
Trees into Females! 
J.B Hiceins 
Horticulturist, Hawait Agricultural Experiment Station, Honolulu, T. H. 
HE papaya, or melon tree, is one 
of the most important tropical 
fruits and because of its delicious 
quality and great yield is des- 
tined, I believe, to be one of the valu- 
able crops in the world’s horticulture 
in the future. 
Its future inportance will depend 
largely on the work of plant breeders, 
to whom it offers some unusually 
interesting features which I propose to 
consider in this paper. 
To those unfamiliar with the tropics, 
it may be said that this tree grows from 
a small seed to a height of 10 or 15 feet 
in a single year, takes on a load of fruit 
equal to that of a 10-year-old apple tree, 
and begins to ripen it about twelve 
months from planting. The large and 
beautiful yellow fruits, weighing on an 
average from three to six pounds, are 
much appreciated in the parts of the 
tropics where attention has been given 
to their cultivation, and are eaten by 
all classes of people. As fruit they 
fit into the same place in the dietary as 
the muskmelon, but to one who would 
inquire what they taste like the only 
reply is—they taste like the papaya. 
The species has been known by many 
common names in Mexico, Central 
America and the West Indies, all of 
which countries have been mentioned 
by different writers as its probable 
home. In English-speaking countries 
it has frequently been called the papaw, 
but this term should be dropped since 
its application to the North American 
papaw, a wholly unrelated species 
(Asimina triloba), is well established. 
The papaya will continue to bear for 
many years, but its period of profitable 
production is only two or three years, 
after which it is cut down to give place 
to young and vigorous stock. The 
growth is so rapid and the tissue so 
soft that a single stroke with a cane 
knife will sever the entire trunk, al- 
though it may be more than a foot in 
diameter. It might be supposed that 
so soft a structure could not support 
the several hundred pounds of fruit 
which not infrequently are borne, but 
since it is all carried close to the trunk 
and the strain is practically vertical, 
the breaking of a papaya tree is rare, 
although the large, picturesque, palm- 
like leaves expose a large surface to the 
wind. 
PECULIARITIES OF SEX 
From a plant breeder’s point of view, 
the most remarkable thing about the 
papaya is its sex. Speaking broadly, 
one would say that the male and female 
flowers are borne on different trees. 
This is an unsatisfactory situation, for 
male trees are of no value to the grower, 
except in the limited number necessary 
for pollination. Yet when the papaya 
is grown from seed, as has usually been 
done in the past, most of the resulting 
plants are males, and the grower’s 
profit is thereby much decreased. 
There are two ways of avoiding this 
difficulty. One which is already being 
used is to propagate the trees not by 
seeds but by grafting. Then one will 
propagate only female fruit-bearing 
trees, with just a few males. This 
method is very useful in prolonging the 
existence of valuable seedlings, but it is 
1In the present paper the author has quoted freely from The Papaya in Hawaii,” by J. E. 
Higgins and Valentine S. Holt. 
208 
Hawaii Agr. Exp. Sta. Bul. No. 32, 1914. 
