1 Viewed from Centre of Eternity 615.552.5747 -+- 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] (818-752-2572) XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XX XX XX Altered States XX XX XX XXXXXXXXXXXXXXXXX | XXXXXXXXXXXXXXXXX XX | XX XXXXXXXXXXXXXXXXX | XXXXXXXXXXXXXXXXX X V