The Unsorted BBS Collection/thegreatunsorted.tar/thegreatunsorted/texts/txtfiles_misc/pot28

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                 -+- The Merry Pranksters from Menlo Park -+-
                               10.1990.01.01.28

                 Marijuana Grower's Handbook - part 28 of 33
                               by pH Imbalance
                                  "Breeding"

                                     from

                         Marijuana Grower's Handbook
                         [Indoor/Greenhouse Edition]
                                 Ed Rosenthal


   Humans have been breeding marijuana informally for thousands of years.
The first farmers chose seeds from the best plants.  Over many generations
the plant was differentiated into varieties which had different uses and
thrived under various environmental conditions.
   Scientific breeding did not begin until Gregor Mendel's experiments on
inherited characteristics were discovered.  Mendel crossed peas with
differing characteristics and found that the offspring plants inherited
traits from their parents in a logical, predictable, statistical way.
[pH:You ever wonder what possesses these people to do shit like that?  Don't
they have lives to lead or something?]
   Today we know that each cell contains a set of chemical blueprints
regarding every aspect of its existence.  These chemical codes are called
chromosomes and they consist of long double strands of sugar which have
"bases" consisting of one of four amino acids.  Sets of three of these amino
acid bases form genes which are "read" by structures in the cell and direct
it in its life processes.
   Chromosomes are found in pairs in most cells.  Half of each pair of
chromosomes is contributed by the male through pollen and half by the
female.  Marijuana has 10 pairs or 20 chromosomes.  Each chromosome's genes
are lined up in a specific order.  The other member of the pair has a
corresponding gene in the same location.  Sometimes, a single gene is
responsible for a characteristic.  In other cases, several genes are
responsible, often in a complex series of reactions.
   There has been very little formal genetic work on marijuana.  Almost all
of the research is the result of observation by cultivators.  However, the
cell and its chromosomes are easily observed using a high-powered
microscope.  Even an inexpensive instrument allows one to see the
chromosomes during mitosis (cell division).  The chromosomes line up in
pairs and then reproduce themselves as the cell splits into two.  When the
reproductive cells are produced, the pairs of chromosomes split and only one
chromosome of each pair goes into each reproductive cell.  (Photographs can
be taken with the aid of a 35 mm SLR camera and an inexpensive adapter
tube.)
   About 2% of the time, the genes "jump" from one member of the pair of
chromosomes to the other.  This is a significant fact in breeding because it
gives individual chromosomes a means of changing information regarding the
characteristics for which they are coded.
   Breeding would be a relatively simple task if only one trait or
characteristic were involved.  However there are many factors to consider
when choosing plants for breeding.  These include:potency, taste, aroma,
color, maturation time, yield, height, branching habits, adaption to
low-light conditions, resistance to pests or diseases, leaf drop at
maturity, and sterility.
   When a plant "breeds true" it means that most of the corresponding genes
on each of the pairs of chromosomes of the 10 pairs have the same
information.  However, plants of different varieties which are crossed are
hybrids, and many of the corresponding genes on the two sets of chromosomes
have information which is in conflict.  For instance, the first generation
cross (an F1 hybrid) may contain genes from one parent programmed for tall
plants and genes from the other parent programmed for short stature.  In
this case the plants all have approximately the same height, intermediate
between the two parents.  When two F1 hybrids are crossed, however, the
plants are either tall, intermediate, or short.  The reason is that some of
the plants have genes for tallness, some for shortness and others for both.
   Many of the important characteristics of marijuana seem to be coded for
"partial dominance" as was just described.  Aroma, taste, and potency seem
to fall into this category.  When more than one gene is involved, there can
be enormous numbers of possible combinations.
   Some characteristics are coded on genes which are either dominant or
recessive.  According to Robert Connell Clarke, author of Marijuana Botany,
tall height, unwebbed leaves, green rather than purple coloring on calyxes
(seed bracts), and large-size seeds are all dominant genes.  A cross between
two plants with conflicting genes would result in the F1 generation all
showing the dominant trait.  A cross between two F1 plants results in a
majority of the plants indicating the dominant trait and onlt a few, those
without the dominant gene on either chromosome, indicating the information
found on the recessive gene.
   It is difficult for the hobbyist or grower to istitute a scientific
breeding program because thousands of plants must be grown to find one
specimen which meets ideal breeding requirements.  Growers have a limited
amount of space to devote to the plants and thus have trouble sorting out
the crosses.  Cultivators can select the best plants in the garden for
breeding.  Sometimes a plant has one outstanding characteristic but is
unexceptional in other respects.  This characteristic can be introduced into
the breeding pool and then the undesirable traits can be "sorted out".
   Marijuana is especially difficult to breed scientifically because half
the plants, those bearing pollen, carry genetic information for hidden
factors.  An observer has few means of judging the genetic potential of male
plants regarding yield, bud structure, and even potency.  There is some
correlation between the male's potency and that of its daughters.  One way
to solve this problem is to induce male flowers on female plants.  Then the
characteristics of both parents are known and all the resulting plants have
only female chromosomes.
   As in humans, gender in cannabis is determined by the "X" and "Y"
chromosomes.  The female has two X chromosomes and the male has one X and
one Y.  When the male plant produces pollen, half of the reproductive cells
receive X and half Y.  However, when the male flowers are artificially
induced in female plants, the pollen contains only X chromosomes, the only
sex chromosomes the female plant has.  All the resulting seeds contain two X
chromosomes, one from each parent.
   To induce male flowers in a female, the plants are sprayed with a
gibberellic acid or watered with an aspirin/water solution.
   Gibberellic acid is a plant hormone originally isolated from
mold-infested rice.  Symptoms of the infection include extraordinary
vertical growth.  Gibberellic acid affects plants in a variety of ways.  In
marijuana, it cases extension of all stems on which it is sprayed, and if
used before flowers develop, it occasionally induces a "sex reversal" in
females: male flowers develop on sprayed areas.  The plant's genetic
structure remains the same, however, the sex characteristics are altered.
In a general way this is similar to a sex change operation; the genetic
information contains information for one sex, but the hormones which are
introduced by the pill or injection artificially induce physiological
changes in the body, including development of the other sex's sexual
characteristics.
   Several correspondents have described the results of adding aspirin to
their water.  One grower used two aspirin in a gallon of water when the
plants were in their third week of flowering.  He said that the plants grew
thousansd of pollen sacs which contained fertile pollen.
   The most methodical way to breed marijuana using these substances is to
allow the plants to flower after taking several clones from each plant.
Once the plants are harvested, cured and testing, the cuttings of all except
those plants selected as the best for breeding are eliminated.  When the
plants are large enough to produce adequate amounts of seed for the
breeder's purposes, some of the plants are kept as females, and male flowers
induced in others.  Then the plants are bred.
   The first step involves gathering the pollen.  Since cannabis is usually
wind-pollinated, it produces an abundance of pollen which floats easily in
the air.  The male plants are placed in a seperate draft-free location and
the pollen drops onto unprinted paper placed underneath the plant.  However,
if there are several plants in the same room, the different plants' pollen
may become contaminated with each other.  If the plants are bent or turned
on their sides so that the pollen has to drop through less air, more pollen
collects.  Plants placed in a cardboard box are even less susceptible to
draft.
   Some growers collect pollen by cutting the flower spikes off the plants
just as the flowers are to open.  These spikes are placed in a paper bag so
no pollen is lost.  Pollen can also be collected by placing a white paper
bag around flower spikes.  White paper is used so that light rays are
reflected rather than absorbed by the bag and turned into heat, which may
damage the plant.  Non-coated parchment paper breathe and eliminates
humidity problems.
   Once the pollen is collected, the female flowers are fertilized.  (If
pollen is scarce, it is diluted 10-100 parts by weight with flour).
Pollination can be accomplished simply by placing a bag filled with pollen
around a bud then shaking it.  The pollen settles for a day or two and then
is removed.  Another method is to "paint" the pollen onto the female flowers
using a small watercolor brush.  [pH:Painting HAPPY marijuana plants!]  One
grower insists that it is easiest to pollinate using your fingers.
   The best time to pollinate marijuana is when the flowers are well
developed but still fresh, and have gone through several stages of growth
and filling out.
   Breeding is a very detailed subject and this is just a cursory discussion
of it.  For more information, I recommend the book, Marijuana Botany by R.C.
Clarke.  [pH:Next on my list]