33 
may be known, but those of the male plant are utterly unknown. 
The parent stock from which both came may be known, but since 
there is wide variation in the fruit of two pistillate trees from the 
same stock it is reasonable to suppose that there will be the same 
wide variation in the male or staminate trees. The variation between 
the pistillate trees can easily be determined because their fruits are 
in evidence and can be tested; but the characters which are inherent 
in the male or staminate tree, and winch will be transmitted by it 
to its progeny, can be determined only through the long process 
of actual hand pollination, the sowing of the seed thus produced, and 
the testing of the fruit. Even then what portion of its excellent 
or indifferent qualities may have been inherited from its male parent 
can not be known. Furthermore, the difficulty becomes aggravated 
by the fact that papaya trees usually degenerate after a few years. 
At least pistillate trees usually fail to produce good fruit after a few 
years of growth, although they may continue to produce indifferent 
fruit for many years. Therefore, even if the inherent characters 
of the male or staminate tree could be determined with reasonable 
accuracy, before any such determination could be made the tree 
would have become too old to be in a reliable state of virility if it 
degenerates as rapidly as the pistillate tree. The new methods 
of asexual propagation referred to on page 9 will aid in overcoming 
this difficulty, but it appears reasonable to suppose that the process 
of producing a stable variety of good qualities by the use of this 
dioecious type would be extremely long and tedious. The hope, 
therefore, must he in the use of a hermaphrodite type. Here it is 
possible to select an individual of known qualities. This may be 
used as the sole parent stock or may be combined with another 
parent of known qualities. What mixtures there may be in the 
individual at the start may not be known; but through repeated selec- 
tions and the elimination of undesirable characters, it should be 
possible to produce a reasonably pure strain, provided, of course, 
that the stock is kept pure by constantly avoiding cross-pollinations 
with plants of different characters, a process which is necessary in 
all plants reproduced by seed and whose flowers are subject to acci- 
dental cross-pollination. 
A further practical difficulty in the use of the dioecious type, from 
the standpoint of the papaya grower, as well as the breeder, is the fact 
that a very large proportion of the trees from any given lot of seed are 
liable to be staminate, or males, and therefore useless, only a few trees 
being necessary to pollinate all the pistillate trees. It is impossible 
so far to distinguish the staminate from the pistillate trees in the 
early stages of their development. Therefore, in any papaya orchard 
planted with the dioecious type, a very large percentage of the trees 
