NoCeilings
Well-Known Member
Source: Marijuana Botany, An Advanced Study. by Robert C Clarke
Some stuff i saved from a pdf a few days ago. Then deleted the pdf. You could probably google it and download the whole thing.
Sex - Attempts to breed offspring of only one sexual
type have led to more misunderstanding than any other
facet of Cannabis genetics. The discoverieas 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.
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.
Galoch (1978] indicated that gibberellic acid (GA3)
promoted stamen production while indoleacetic acid (IAA),
ethrel, and kinetin promoted pistil production in prefloral
dioecious Cannabis. Hormones might be used to change the sex of a cutting from the desirable plant, and this cutting used to mate with it.
This is most easily accomplished by changing a pistillate
cutting to a staminate (pollen) parent, using a spray of 100
ppm gibberellic acid in water each day for five consecutive
days. Within two weeks staminate flowers may appear.
Pollen can then be collected for selfing with the original
pistillate parent. Offspring from the cross should also be
mostly pistillate since the breeder is selfing for pistillate
sexuality. Staminate parents reversed to pistillate floral
production make inferior seed-parents since few pistillate
flowers and seeds are formed.
good stuff
Some stuff i saved from a pdf a few days ago. Then deleted the pdf. You could probably google it and download the whole thing.
Sex - Attempts to breed offspring of only one sexual
type have led to more misunderstanding than any other
facet of Cannabis genetics. The discoverieas 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.
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.
Galoch (1978] indicated that gibberellic acid (GA3)
promoted stamen production while indoleacetic acid (IAA),
ethrel, and kinetin promoted pistil production in prefloral
dioecious Cannabis. Hormones might be used to change the sex of a cutting from the desirable plant, and this cutting used to mate with it.
This is most easily accomplished by changing a pistillate
cutting to a staminate (pollen) parent, using a spray of 100
ppm gibberellic acid in water each day for five consecutive
days. Within two weeks staminate flowers may appear.
Pollen can then be collected for selfing with the original
pistillate parent. Offspring from the cross should also be
mostly pistillate since the breeder is selfing for pistillate
sexuality. Staminate parents reversed to pistillate floral
production make inferior seed-parents since few pistillate
flowers and seeds are formed.
good stuff