Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

This research was flimsy and unscientific at best, and ever since this report, many cannabis growers have attempted inducing polyploidy in many varieties, none leading to agronomic success.
    Diploid plants are considered normal and have one set of chromosomes, which occur in pairs within each plant cell. Polyploid plants have more than one set of chromosomes per cell. Polyploid plant chromosomes occur in groups of 3-4 instead of in pairs. Tetraploid plants groups occur with four chromosomes in each cell.
    At one time, breeders believed that polyploid and tetraploid plants would produce a superior resin-packed plant.
    The polyploid characteristic can be induced with an application of colchicine. Just remember, colchicine is a poison, and polyploid plants do not contain more THC-potent resin.
Mutagenesis-lnducing Variation
    If variation does not exist for the trait or traits of interest, or cannot be found in other populations, it is theoretically possible to induce variation by exposing seeds or other tissues to radiation, alkylating agents, or other mutagens such as colchicine or EMS (ethylmethylsulfonate). These treatments cause changes at the DNA level that have the remote potential to result in desirable, novel phenotypes.
    There is much rumour and speculation about this technique amongst breeders and growers. It’s a common myth that treating seeds with colchicine and growing the plants results in more potent cannabis plants. Let’s put this myth to rest; it is completely untrue. While the possibility does exist on a theoretical level, no valid experiments have ever shown this to be true. Potential breeders would be better off using their time and space for selecting better plants than trying this technique as a method for improving plant stock.
    That being said, let’s take a look at the theory behind the concept.
    Imagine you have a population of plants which, when grown from seed and inbred within the population, consistently produces high-THC plants. It is theoretically possible to treat many of these seeds with a mutagen, grow and inbreed the seeds, and find plants in subsequent generations that produce no THC. These mutagens can destroy genes along a chromosome, and when copies of this chromosome are inherited by future generations, a new or “novel” phenotype can appear. In our example, the no THC condition is the novel phenotype.
    These mutations, however, occur at random and are extremely unreliable. The probability of finding plants which have a desired mutation in the gene of interest is very low. A breeder may treat many thousands of seeds, grow 100,000 plants, and still not see the desired altered phenotypes. This technique is costly in both time and space. It is often used in the breeding of “legal plants” when growing out thousands of individuals and searching for these novel phenotypes is not problematic. Performing such population screens in cannabis is not practical, especially for clandestine breeders. The potentially hazardous nature of these mutagenic agents is another very good reason to choose other breeding options. Inducing variability is likely not the best option, at least for the hobby breeder.
    If you are serious about breeding cannabis, check out Marijuana Botany, An Advanced Study: The Propagation and Breeding of Distinctive Cannabis, by Robert Connell Clarke, Ronin Press. Using understandable scientific detail, Clarke discusses genetics and breeding, chemistry, and much more of interest to the budding breeder. This book is worth its weight in ‘Haze’ buds. If you can’t find it at the bookstore, check out our web site: www.marijuanagrowing.com .

APPENDIX
Conversion Charts and Tables
Carbon Dioxide Facts and Figures
    molecular weight = 44 grams/mole
    sublimes (solid to gas) at 78.5°C at 1 atmosphere - air density = 1.2928 grams/liter (i.e., at equal temperatures and pressures carbon dioxide is heavier than air, and CO 2 will fall to the bottom of an air/ CO 2 mixture.
    psi = 1 atmosphere
    Physical properties of Propane:

Calculations for Metric Users
    1 cubic meter = 1 m × 1 m × 1 m = 1000 liters
    fans are rated at liters per minute or liters per second
    cubic feet = L × W × H
    cubic meters = L × W × H
    Buy a fan that will clear the grow room volume of air in one to five minutes. Run the fan for twice the time to theoretically clear the grow room of air.
    Work out the amount of CO 2 gas to add:
    For example, if you want 1500 ppm and ambient CO 2 is 350 ppm, you