........ " Attempts to breed offspring of only one sexual type have led to more misunderstanding than any other
facet of Cannabis genetics. The discoveries of McPhee (1925) and Schaffner (1928) showed that pure
sexual type and hermaphrodite conditions are inherited and that the percentage of sexual types could be
altered by crossing with certain hermaphrodites. Since then it has generally been assumed by researchers
and breeders that a cross be- tween ANY unselected hermaphrodite plant and a pistillate seed-parent
should result in a population of all pistillate offspring. This is not the case. In most cases, the offspring
of hermaphrodite parents tend toward hermaphrodism, which is largely unfavorable for the production
of Cannabis other than fiber hemp. This is not to say that there is no tendency for hermaphrodite crosses
to alter sex ratios in the offspring. The accidental release of some pollen fro predominantly pistillate
hermaphrodites, along with the complete eradication of nearly every staminate and stami- nate
hermaphrodite plant may have led to a shift in sexual ratio in domestic populations of sinsemilla drug
Cannabis. It is commonly observed that these strains tend toward 60% to 80% pistillate plants and a few
pistillate hermaph- rodites are not uncommon in these populations.
However, a cross can be made which will produce nearly all pistillate or staminate individuals. If the
proper pistillate hermaphrodite plant is selected as the pollen- parent and a pure pistillate plant is
selected as the seed- parent it is possible to produce an F1, and subsequent generations, of nearly all
pistillate offspring. The proper pistillate hermaphrodite pollen-parent is one which has grown as a pure
pistillate plant and at the end of the sea- son, or under artificial environmental stress, begins to develop a
very few staminate flowers. If pollen from these few staminate flowers forming on a pistillate plant is
applied to a pure pistillate seed parent, the resulting F1 generation should be almost all pistillate with
only a few pistillate hermaphrodites. This will also be the case if the selected pistillate hermaphrodite
pollen source is selfed and bears its own seeds. Remember that a selfed hermaphrodite gives rise to more
hermaphrodites, but a selfed pistillate plant that has given rise to a limited number of staminate flowers
in response to environmental stresses should give rise to nearly all pistillate offspring. The F1 offspring
may have a slight tendency to produce a few staminate flowers under further environmental stress and
these are used to produce F2 seed. A monoecious strain produces 95+% plants with many pistillate and
staminate flowers, but a dioecious strain produces 95+% pure pistillate or staminate plants. A plant from
a dioecious strain with a few inter- sexual flowers is a pistillate or staminate hermaphrodite. Therefore,
the difference between monoecism and her- maphrodism is one of degree, determined by genetics and
environment.
Crosses may also be performed to produce nearly all staminate offspring. This is accomplished by
crossing a pure staminate plant with a staminate plant that has pro- duced a few pistillate flowers due to
environmental stress, or selfing the latter plant. It is readily apparent that in the wild this is not a likely
possibility. Very few staminate plants live long enough to produce pistillate flowers, and when this does
happen the number of seeds produced is limited to the few pistillate flowers that occur. In the case of a
pistillate hermaphrodite, it may produce only a few staminate flowers, but each of these may produce
thou- sands of pollen grains, any one of which may fertilize one of the plentiful pistillate flowers,
producing a seed. This is another reason that natural Cannabis populations tend toward predominantly
pistillate and pistillate hermaphro- dite plants. Artificial hermaphrodites can be produced by hormone
sprays, mutilation, and altered light cycles. These should prove most useful for fixing traits and sexual
type. " ........... Robert C Clarke
