[Aquaman2112]

It is possible to breed and select cuttings from plants that grow, flower, and mature faster. Some plants will naturally be better than others in this regard, and it is easy to select not only the most potent plants to clone or breed, but the fastest growing/flowering plants as well. Find your fastest growth plant, and breed it with your "best high" male for fast flowering, potent strains. Clone your fastest, best high plant for the quickest monocrop garden possible. Over time, it will save you a lot of waiting around for your plants to mature.
When a male is starting to flower (2-4 weeks before the females) it should be removed from the females so it does not pollinate them. It is taken to a separate area. Any place that gets just a few hours of light per day will be adequate, including close to a window in a separate room in the house. Put newspaper or glass under it to catch the pollen as the flowers drop it.
Keep a male alive indefinitely by bending the top severely and putting it in mild shock that delays it is maturity. Or take the tops as they mature and put the branches in water, over a piece of plate glass. Shake the branches every morning to release pollen onto the glass and then scrap it with a razor blade to collect it. A male pruned in this fashion stays alive indefinately and will continue to produce flowers if it gets suitable dark periods. This is much better than putting pollen in the freezer! Fresh pollen is always best.
Save pollen in an air tight bag in the freezer. It will be good for about a month. It may be several more weeks before the females are ready to pollinate. Put a paper towel in the bag with it to act as a desecant.
A plant is ready to pollinate 2 weeks after the clusters of female flowers first appear. If you pollinate too early, it may not work. Wait until the female flowers are well established, but still all while hairs are showing.
Turn off all fans. Use a paper bag to pollinate a branch of a female plant. Use different pollen from two males on separate branches. Wrap the bag around the branch and seal it at the opening to the branch. Shake the branch vigorously. Wet the paper bag after a few minutes with a sprayer and then carefully remove it. Large plastic zip-lock bags also. Slip the bag over the male branch and shake the pollen loose. Carefully remove the bad and zip it up. It should be very dusty with pollen. To pollinate, place it over a single branch of the female, zipping it up sideways around the stem so no pollen leaks out. Shake the bag and the stem at the same time. Allow to settle for an hour or two and shake it again. Remove it a few hours later. Your branch is now well pollinated and should show signs of visible seed production in 2 weeks, with ripe seeds splitting the calyxes by 3-6 weeks. One pollinated branch can create hundreds of seeds, so it should not be necessary to pollinate more than one or two branches in many cases.
When crossing two different varieties, a third variety of plant will be created. If you know what characteristics your looking for in a new strain, you will need several plants to choose from in order to have the best chance of finding all the qualities desired. Sometimes, if the two plants bred had dominant genes for certain characteristics, it will be impossible to get the plant you want from one single cross. In this case, it is necessary to interbreed two plants from the same batch of resultant seeds from the initial cross. In this fashion, recesive genes will become available, and the plant character you desire may only be possible in this manner.
Usually, it is desirable only to cross two strains that are very different. In this manner, one usually arrives at what is refered to as "hybrid vigor". In other words, often the best strains are created by taking two very different strains and mating them. Less robust plants may be the result of interbreeding, since it opens up recesive gene traits that may lead to reduced potency.
Hybrid offspring will all be very different from each other. Each plant grown from the same batch of seeds collected from the same plant, will be different. It is then necessary to try each plant separately and decide it is individual merits for yourself. If you find one that seems to be head and shoulders above the rest in terms of early flowering, high yield and get buzz, that is the plant to clone and continue breeding.
In depth genetics is beyond the scope of this work. See Marijuana Botany; Smith, for more detailed info in this area.

[Aquaman2112]

How to create amazing new strains with a discerning palate, careful selection and some hard work.
Perhaps the most important aspect to consider in the breeding of fine quality cannabis is that of selection. Selective breeding is where all of today's varieties evolved from.

In the past, this chore was made easier by the fact that most of the commercially available herb was seeded and imported from outdoor plantations, usually near-equatorial in origin. These "land-race" Sativa varieties were the building blocks of the burgeoning domestic productions of the times.

The Indica (Afghan, Kush, Skunk, etc.) genetics were specially imported by West Coast interests and available to the general public around 1978. It was shortly after this time that the variance of domestic cannabis increased exponentially, as people began experimenting with crossing these two different types of pot.

Beginning breeding

The typical way to begin a breeding program is to carefully select P1 parents of pure Sativa and pure Indica, crossing them to produce an f1 hybrid that is uniform in its phenotypic growth patterns. The next step is the crossing of the f1 type with itself, which produces a very wide variation witnessed in the f2 growth patterns and expressions.

It is in this f2 second-generational cross and beyond that the art of selection really comes into play. There are a number of factors to consider at this point, such as what the male and female will each contribute; and most of all, what will the overall quality of the finished product be like?

Defining a goal and constructing a plan to accomplish it is called "top-down" programming, and this "top-down" approach applies well to cannabis breeding. It helps considerably to have a specific goal in mind when attempting to selectively breed a variety of ganja. This simple fact I cannot emphasize enough.

One must at least have an idea of what one is aiming for before beginning. For me this has little to do with plant structure and much to do with the quality of the finished product, no matter what form it is in. Having an experienced and educated palate (both mentally aesthetic and physically discernable) is key in the art of breeding fine quality cannabis.

The "goal" at the center of most of my breeding targets would be to replicate, as near as possible, the experiences produced by the great land-race varieties of old: Highland Oaxacan or Thai, Santa Marta or Acapulco Gold, Guerrero Green, Panama Red or Hawaiian Sativa… or the hash from regions such as Lebanon, Afghanistan or Nepal.

The indoor grow environment is too generic to fully replicate the great old legends. Therefore, it was necessary to settle for the next best thing: happy Sativa/Indica crosses that would perform well indoors. (It is interesting to note here that most of the fine land-race Sativa were hermaphroditic, though sometimes only minimally.)


Outdoor Australian Sativa; inset: seeded bud
Selection process

Obviously, you seek the parents that will produce the desired progeny. Paradoxically, this process requires selecting the best after they've been harvested. The solution is to keep samples from each plant of a test crop. This can be done via rooted clones from earlier cuttings, or re-greened mothers and fathers kept in a vegetative state and a high-nitrogen diet. Once you have chosen among the harvested plants, you can use the rooted cuttings for future consideration and possible breeding.

Pollen may also be gathered and immediately stored via vacuum sealing and deep-freezing. It is crucial to vacuum seal and freeze pollen immediately after it is collected and to use stored pollen immediately after it thaws. Dry seeds also store well over indefinite periods of time in an undisturbed deep-freeze, with some desiccant.

This process of post-harvest selection works fine for selecting desired female plants. But what about males? What is the best and most simple way to select males for breeding? Due to the fact that it is the female plants that we are ultimately familiar with, selecting males is a bit more involved.

The process is basically the same as it is with female plants, except with males the numbers are first limited down via a process of elimination, and selections made by comparing the remainder. Selecting males also takes a little more time initially as the quality of the male is not fully determined until after the seeds it produces are grown out and tested. As one becomes more familiar with a particular strain, the specific characteristics of the desirable males become apparent.

Ideally, the more seeds one starts with the better. This is, after all, a numbers game. I will assume that any basic breeding project starts with at least 20 different plants, from 20 viable seeds of high quality, professionally stabilized varieties. This would give a minimum of 10 male and 10 female plants hopefully sexed by two weeks into a flowering light cycle (short day/long night).

Once sexed, the process of elimination may begin. All of the females are kept and regularly examined to prevent unwanted hermaphroditism. Unwanted males and all hermaphrodites must be eliminated before they begin to shed pollen – usually by the third week in the flowering cycle. The female plants need to be checked for hermaphroditism until harvest.

(A quick word on "backward" hermaphrodites – declared males that eventually sport female flowers – as opposed to the usual female-to-male hermaphrodites. These are semi-rare occurrences, usually sterile but sometimes viable, that I have found at times to be valuable in their genetic contributions. Some of the most resinous and desirable males I have encountered exhibited this trait. This trait almost seems to guarantee against unwanted hermaphroditism in subsequent generations as it also increases the female to male ratio in its progeny.)

[Aquaman2112]

Recessivecombination

A word needs to be said about the not-too-common probabilities of what I generally refer to as a recessive combination phenomenon. Sometimes, though not often, two parents that appear to express a common desirable trait – let's say a sweet/fruity bouquet – are crossed and the progeny do not express the desirable trait.

This usually means that one or both parents possessed some sort of recessive alleles in their genotype for this characteristic. But it could also mean that the progeny had a different environment that the parents.

If environment can be ruled out then it is likely that some sort of a genetic recessive combination is the cause. If none of the progeny express the desired characteristic one may want to cross the progeny with itself and see what the outcome is.

If a common "Punnet ratio" such as 25% of a progeny express the desirable trait, then the trait is more than likely recessive and the trait may be stabilized via crossing any two of the 25% (or whatever common ratio) that show the desired trait with each other. This process is time consuming and is generally followed only if no other alternatives exist.


Male plants showing their sex.
Selecting males

I prefer to remove all of the males from the grow-room to a separate, isolated space shortly after they declare their sex and well before they begin to shed pollen. A small space lit with simple fluorescent light will suffice for the males for the next few weeks. During this time the female buds will fatten with more flowers while your collection of males is selected down.

I generally employ a simple process of elimination while selecting males. First, any auto-flowering or very early-declared males are eliminated. (Auto-flowering means that male flowers form regardless of light cycle timing.) This is mainly to insure against hermaphroditism or unwanted flowering traits, but also as a means to insure quality. The very early declared males have a tendency to be less desirable in terms of their contributions to the quality of the finished product. (If you are trying to specifically create an early-flowering strain, then your priorities may be different.)

Next, any male plant that grows too tall or too fast is usually eliminated. The reason for this is that most plants which dedicate so much energy to fiber production generally are best for making fiber. The exception to this rule is when an over-productive plant also exhibits a number of the desirable characteristics mentioned later.

The next criteria for elimination is borrowed from Michael Starks' book, Marijuana Potency, and involves stem structure. Large, hollow main stems are sought while pith-filled stems are eliminated. Backed by years of observation, I agree that hollow stems do seem to facilitate THC production.

Another consideration is the type of floral clusters that develop. Even on males, clusters which are tight, compact and yet very productive are desired over an airy, loose structure. These observations are most notable in the indoor environment. Outdoors, the differences in stem and floral structures are more difficult to discern.

The next and perhaps most important characteristic to examine is that of odor, flavor and trichome development. Again, the females will prove themselves by their finished product, but the males are a bit trickier.

I usually begin with a Sativa female and an Indica male. It has been my observation that the females primarily contribute the type of flavor and aroma and the males contribute the amount of flavor and odor. The "Sativa/Indica" aspects of this formula are mainly apparent in the P1 or very early filial crosses (to about f3). Beyond the f3 generation the apparent "Sativa/Indica" ratio in a given individual is less important than the odor/flavor and trichome development aspects it exhibits. Therefore, one of the main aspects to consider when selecting a male is the depth of its aroma and flavor. (If you are seeking to develop a low-odor indoor strain you might wish to begin with a low-odor Sativa male and an Indica female.)

With the remaining males I usually employ an odor/flavor test. Using males at least two or three weeks into the flowering cycle (and preferably beyond if a separate, isolated space is being used), a sort of "scratch-and-sniff" technique is first employed. With clean, odor-free fingers, gently rub one plant at a time, on the stem where it is well developed and pliable, above the woody part and below the developing top (approximately at the spot where a clone would be cut). The newer leaves at their halfway point of development may also be rubbed and sniffed.

These are the places that the earliest chemical signatures of a developing plant present themselves, and it is our intent to gently disturb these chemicals and inspire an odor/flavor reaction on the fingers and on the plant. By examining these various aromas in this way one may be able to determine certain desirable (and also undesirable) characteristics. After clearing one's palate and refreshing one's fingers, another plant may be tested.

The finalists are best compared for at least a week and at different times of day, to determine who performs best over a period of time.

A few of the "good" aromas which I have found to be associated with both male and female high quality cannabis are: sweet, floral, fruity, berry, wine/brandy, other savory spirits, skunky and spearmint. Some of the "bad" aromas associated with both male and female cannabis are: grassy, chlorophyll (green), celery, parsley, carrots, cinnamon, pepper-mint or wintergreen, gear-oil and gasoline. Some of the aromas that are considered "good" from females but not necessarily from males are: woody, cedar, pine, citrus, tropical fruit, chocolate, vanilla, coffee, garlic and astringent.

Worldwide weed

It is sad that due to the Unfortunate State of Assholes in the world today we herbalists are treated criminally. Sad because given saner times we would be able to produce vast amounts of fine quality herb by virtue of no more than the great outdoors, large numbered populations and trial and error.

Someday perhaps, but in the meantime I have few alternate suggestions. Holland, Denmark, Switzerland, Spain and other parts of Europe are opening up more and more toward herbal tolerance. It is relatively easy in these places to score some high quality product.

It is advisable for the newbie to a scene to buy many small samples of herbals at first until one finds what one likes. Just like in any other travel situation, special surprises await those willing to venture out from the centralized tourist areas (except in Christiania where "one stop shopping" is greatly enjoyed).

I am willing to bet that some of the many herbal "sweet spots" around the globe may once again be producing their specialties. I am eager to verify any rumor of such possibilities. These sweet spots would include many equatorial and near equatorial regions such as Colombia, Highland Mexico, parts of Thailand, Burma and Bhutan to name a few. Places such as Nepal and Jamaica have been ideal for herbal expeditions as well. These are some of the places one could venture in search of educating one's herbal palate and expanding one's experience. n

[Aquaman2112]

Constant testing

After selections are made, it is also necessary to remember to test for these qualities across a number of clone generations. Do the desirable characteristics present in a new plant (from seed) persist through the following clone generations of that plant? Does the plant from clones of the original carry the same odor/flavor quality? The same potency? Overall desirability? The answers most definitely need to be "yes" if that individual is to be considered for future breeding.

With much practice and years of experience it becomes apparent to those with a sensitive palate which individuals possess the most desirable characteristics from a given sample.
I suggest that your taste and smell be augmented with the use of an illuminated magnifier, either 30X, 60X or 100X power
will do.

Look at the same aforementioned spot on the stem or developing leaves any time after the second week in the bud cycle and look for the greatest abundance of developing trichomes or secretory hairs (hairs that secrete fluid obvious at 30X and above magnification). More fully developed trichomes with very clear heads are generally the most desirable.

These observations need to be done over a period of time (that is, not just a one-time look) and at different times of the day to determine which individuals perform best. Many various phenomena become apparent to those who are able to pay close attention over a period of time. To that effect I suggest you compile and composite detailed notes on one's observations, and to compare those notes over time. Detailed, comprehensive notes are the hallmark of any successful breeding program.

It is possible to test males by smoking or otherwise consuming them. This practice may be somewhat beneficial to beginners as it does involve a sort of obvious discretion. I suggest using only fresh tips, properly cured and rolled into a joint. Also, make sure that this test smoke is the first smoke one consumes in a day in order to best discern its qualities, or lack thereof.

Some other aspects to consider

There are a number of aesthetic considerations to consider regarding fine quality cannabis breeding, such as color, overall structure, growth patterns and various bouquets. My primary goal involves finding the finished product with the most desirable and pleasant effects. So I focus on those aspects and stabilize them first. Once stabilized, a backcross or a cross to another variety may be utilized to further improve the line and/or increase vigor, if necessary.

On the experimental level the finished product is expected to be either pleasant or powerful, depending on the individual. I prefer an herb that is pleasantly powerful or powerfully pleasant! So that is the sought-after goal. The range of experiences elicited by cannabis can vary from bliss to panic to stupefying. I much prefer the bliss aspects.

The best descriptive dichotomy in this case would be comfort vs. discomfort. I also suppose some personality types may enjoy a more exciting experience – perhaps only once in awhile – a feeling somewhat akin to the entertainment of a roller coaster ride or a horror movie.

Cannabis is unusual in its varying effects on our vascular-circulatory system. Some cannabis strains seem to act as a vasodilator and others as a vasoconstrictor. A vasoconstrictor is a substance that constricts blood vessels. It tends to elicit tension, excitement, anxiety, and even panic. A vasodilator is a substance that dilates blood vessels and tends to relax a person more easily into a blissful state. Therefore, I tend to prefer cannabis that seems to act as a vasodilator, simply not to the point of couch lock sedation.

I have nothing against powerfully stony herb. It is just that as long as my breeding space is limited, I will choose to work with the more pleasant varieties – those that elicit a generally happy experience. Someday I look forward to working at stabilizing many different varieties of herb. After all, to each their own.

Tinnitus and dyskinesia are common symptoms of a vasoconstrictor reaction. Tinnitus is ringing in the ears, and dyskinesia, in this instance, is usually felt as a tingling in the extremities, especially the little fingers, toes and ears. Another bad sign would be any form of tension headache or unwanted body load. If these symptoms occur regularly after indulging in a particular herb, the herb may be contributing to the sensation.

[Aquaman2112]

Does it pass the acid test?

To borrow and paraphrase a disclaimer from Dr Hunter S Thompson; "I cannot condone drug usage, but I must admit it has worked well for me." In particular, the psychedelics (entheogens, entactogens, and hallucinogens included) are paramount as a testing tool when breeding fine quality cannabis.

A favored testing formula of mine involves preparations being made days in advance. One needs to have a perfectly cured sample of the herb one wishes to test ready at hand before the test. Fasting (from substances primarily, but also some foods) and cleansing (exercise, sweating or sauna, re-hydration and meditation, etc.) are employed for a period prior to the test. This is to as fully as possible re-calibrate one's baseline state of consciousness to its most basic, clean state.

A time is selected, a toast made and the trip material is ingested. I generally like to eat a simple meal of soup or juice and bread after I ingest a substance and before I begin to alert (first noticing the effect of a substance).

Do not ingest any herb, or any other consciousness-altering substance until after one has alerted, preferably prior to the peak of the trip. Ingest only a small amount of the herb to be tested at first, one toke at a time, unless this is a follow-up test and one is already familiar with the experience.

Ideally, the psychedelic substance will further the range of noticeable subtleties by one's psyche and allow a broader appreciation of the effect from the herb. An herb that is truly powerful and pleasant will usually profoundly express its experience upon the opened mind. That is, if the herb is truly blissful it will become more readily apparent under such psychedelic examination. Likewise, if the herb is somewhat "panicky" or "anxious" in experience, the psychedelic will exacerbate these qualities as well.

I am assuming, and offering fair warning, that those who attempt such a test are well-experienced psychic travelers. That is, all necessary considerations of set and setting must be satisfied before attempting such a trial. The psychedelic substance almost seems to act as a sort of mental catalyst when combined with herb. This combination is able to cause both desirable and undesirable traits of the herb experience to become more so apparent to the initiated mind.

These are some of the techniques, selections and considerations that I employ when breeding fine quality cannabis. Famed horticulturist Luther Burbank's quote: "select the best and reject all others" is the single most important aspect to consider.

With time, focus and patience the knack for recognizing desirable and undesirable traits becomes more apparent. Having an open and curious mind, along with a developed sense of intuition, is beneficial.

May your ventures be fruitful.

Recessivecombination

A word needs to be said about the not-too-common probabilities of what I generally refer to as a recessive combination phenomenon. Sometimes, though not often, two parents that appear to express a common desirable trait – let's say a sweet/fruity bouquet – are crossed and the progeny do not express the desirable trait.

This usually means that one or both parents possessed some sort of recessive alleles in their genotype for this characteristic. But it could also mean that the progeny had a different environment that the parents.

If environment can be ruled out then it is likely that some sort of a genetic recessive combination is the cause. If none of the progeny express the desired characteristic one may want to cross the progeny with itself and see what the outcome is.

If a common "Punnet ratio" such as 25% of a progeny express the desirable trait, then the trait is more than likely recessive and the trait may be stabilized via crossing any two of the 25% (or whatever common ratio) that show the desired trait with each other. This process is time consuming and is generally followed only if no other alternatives exist.

[Aquaman2112]

Ganja Godesses

One of the things I learned a long time ago was that something more than genetics or biological environment plays a role in the desirability of herb. During the 70's and 80's, as the number of growers proliferated, it became apparent to those privy to the info that a grower's personal vibe somehow became part of the plant's vibe.

Generally speaking, mellow, laid-back growers tended to produce mellow, laid-back herb, whereas uptight, sinister growers tended to produce uptight, sinister herb. Perhaps it was just the vibe of the grower following the product to market expressing itself along the chain of trade, I am not certain, nor do I believe any form of scientific observation will ever confirm such a debate. It has simply been one of those givens in the trade. In that regard, I have further noticed that much of the finest domestic herb I've encountered was grown by women.

I used to call it the "Great Pumpkin" effect, but perhaps it is better termed the "Ganja Goddess" effect. The most sincere herbal patches being visited upon by the subtle and ethereal spirits of benevolence. And subtle is a very key word when considering the desirable characteristics of fine quality cannabis. Subtleties have a way of being very powerful, indeed. While we are considering such aesthetic topics let's have a look at femininity. It is, after all, the female plant we are primarily concerned with.

One of the most profound aspects of the cannabis experience for me is its ability to act as a counter-balance to my personal, male-dominance syndrome.

Cannabis allows me a reprieve from the otherwise distracting male-conditioned response of attempting to dominate my environment. My conditioning of aggressive competitiveness is temporarily quelled, and I am allowed to experience reality in a much more non-linear relationship. The routine desire to compete and conquer is replaced with a sense of cooperation and community. In a word, I have learned to become a feminist.

By "feminist" I mean the protected right to be feminine, cooperative, community-centered and globally concerned, able and free to discern subtleties, intuitive and submissive without the fear of dominator conquest and control. The fine quality cannabis experience allows me to better understand, accept, and serve fate.

One of the things I have learned about "us" (the cooperators) and "them" (the dominators) is that they need us much more than we need them. This is one fact that I wish very much for our community to realize. Toward realizing that end, I have found the finest quality cannabis to be an invaluable resource.

"The greatest service which can be rendered to any country is to add a useful plant to its culture."
- Thomas Jefferson

Genetics
Although it is possible to breed Cannabis with limited success without any knowledge of the laws of inheritance, the full potential of diligent breeding, and the line of action most likely to lead to success, is realized by breeders who have mastered a working knowledge of genetics.
As we know already, all information transmitted from generation to generation must be contained in the pollen of the staminate parent and the ovule of the pistillate parent. Fertilization unites these two sets of genetic information, a seed forms, and a new generation is begun. Both pollen and ovules are known as gametes, and the transmitted units determining the expression of a character are known as genes. Individual plants have two identical sets of genes (2n) in every cell except the gametes, which through reduction division have only one set of genes (in). Upon fertilization one set from each parent combines to form a seed (2n).
In Cannabis, the haploid (in) number of chromosomes is 10 and the diploid (2n) number of chromosomes is 20. Each chromosome contains hundreds of genes, influencing every phase of the growth and development of the plant.
If cross-pollination of two plants with a shared genetic trait (or self-pollination of a hermaphrodite) results in off spring that all exhibit the same trait, and if all subsequent (inbred) generations also exhibit it, then we say that the strain (i.e., the line of offspring derived from common ancestors) is true-breeding, or breeds true, for that trait. A strain may breed true for one or more traits while varying in other characteristics. For example, the traits of sweet aroma and early maturation may breed true, while off spring vary in size and shape. For a strain to breed true for some trait, both of the gametes forming the offspring must have an identical complement of the genes that influence the expression of that trait. For example, in a strain that breeds true for webbed leaves, any gamete from any parent in that population will contain the gene for webbed leaves, which we will signify with the letter w. Since each gamete carries one-half (in) of the genetic complement of the offspring, it follows that upon fertilization both "leaf shape" genes of the (2n) offspring will be w. That is, the offspring, like both parents, are ww. In turn, the offspring also breed true for webbed leaves because they have only w genes to pass on in their gametes.
On the other hand, when a cross produces offspring that do not breed true (i.e., the offspring do not all resemble their parents) we say the parents have genes that segregate or are hybrid. Just as a strain can breed true for one or more traits, it can also segregate for one or more traits; this is often seen. For example, consider a cross where some of the offspring have webbed leaves and some have normal compound-pinnate leaves. (To continue our system of notation we will refer to the gametes of plants with compound-pinnate leaves as W for that trait. Since these two genes both influence leaf shape, we assume that they are related genes, hence the lower-case w and upper-case W notation instead of w for webbed and possibly P for pinnate.) Since the gametes of a true-breeding strain must each have the same genes for the given trait, it seems logical that gametes which produce two types of offspring must have genetically different parents.
Observation of many populations in which offspring differed in appearance from their parents led Mendel to his theory of genetics. If like only sometimes produces like, then what are the rules which govern the outcome of these crosses? Can we use these rules to predict the outcome of future crosses?
Assume that we separate two true-breeding populations of Cannabis, one with webbed and one with compound-pinnate leaf shapes. We know that all the gametes produced by the webbed-leaf parents will contain genes for leaf-shape w and all gametes produced by the compound-pinnate individuals will have W genes for leaf shape. (The offspring may differ in other characteristics, of course.)
If we make a cross with one parent from each of the true-breeding strains, we will find that 100% of the off spring are of the compound-pinnate leaf phenotype. (The expression of a trait in a plant or strain is known as the phenotype.) What happened to the genes for webbed leaves contained in the webbed leaf parent? Since we know that there were just as many w genes as W genes combined in the offspring, the W gene must mask the expression of the w gene. We term the W gene the dominant gene and say that the trait of compound-pinnate leaves is dominant over the recessive trait of webbed leaves. This seems logical since the normal phenotype in Cannabis has compound-pinnate leaves. It must be remembered, however, that many useful traits that breed true are recessive. The true-breeding dominant or recessive condition, WW or ww, is termed the homozygous condition; the segregating hybrid condition wW or Ww is called heterozygous. When we cross two of the F1 (first filial generation) offspring resulting from the initial cross of the ~1 (parental generation) we observe two types of offspring. The F2 generation shows a ratio of approximately 3:1, three compound pinnate type-to-one webbed type. It should be remembered that phenotype ratios are theoretical. The real results may vary from the expected ratios, especially in small samples.
In this case, compound-pinnate leaf is dominant over webbed leaf, so whenever the genes w and W are combined, the dominant trait W will be expressed in the phenotype. In the F2 generation only 25% of the offspring are homozygous for W so only 25% are fixed for W. The w trait is only expressed in the F2 generation and only when two w genes are combined to form a double-recessive, fixing the recessive trait in 25% of the offspring. If compound-pinnate showed incomplete dominance over webbed, the genotypes in this example would remain the same, but the phenotypes in the F1 generation would all be intermediate types resembling both parents and the F2 phenotype ratio would be 1 compound-pinnate :2 intermediate :1 webbed.
The explanation for the predictable ratios of offspring is simple and brings us to Mendel's first law, the first of the basic rules of heredity:

[Aquaman2112]

I. Each of the genes in a related pair segregate from each other during gamete formation.
A common technique used to deduce the genotype of the parents is the back-cross. This is done by crossing one of the F1 progeny back to one of the true-breeding P1 parents. If the resulting ratio of phenotypes is 1:1 (one heterozygous to one homozygous) it proves that the parents were indeed homozygous dominant WW and homozygous-recessive ww.
The 1:1 ratio observed when back-crossing F1 to P1 and the 1:2:1 ratio observed in F1 to F1 crosses are the two basic Mendelian ratios for the inheritance of one character controlled by one pair of genes. The astute breeder uses these ratios to determine the genotype of the parental plants and the relevance of genotype to further breeding.
This simple example may be extended to include the inheritance of two or more unrelated pairs of genes at a time. For instance we might consider the simultaneous inheritance of the gene pairs T (tall)/t (short) and M (early maturation)/m (late maturation). This is termed a polyhybrid instead of monohybrid cross. Mendel's second law allows us to predict the outcome of polyhybrid crosses also:
II. Unrelated pairs of genes are inherited independently of each other.
If complete dominance is assumed for both pairs of genes, then the 16 possible F2 genotype combinations will form 4 F2 phenotypes in a 9:3:3:1 ratio, the most frequent of which is the double-dominant tall/early condition. In complete dominance for both gene pairs would result in 9 F2 phenotypes in a 1:2:1:2:4:2:1:2:1 ratio, directly reflecting the genotype ratio. A mixed dominance condition would result in 6 F2 phenotypes in a 6:3:3:2:1:1 ratio. Thus, we see that a cross involving two independently assorting pairs of genes results in a 9:3:3:1 Mendelian phenotype ratio only if dominance is complete. This ratio may differ, depending on the dominance conditions present in the original gene pairs. Also, two new phenotypes, tall/late and short/early, have been created in the F2 generation; these phenotypes differ from both parents and grand parents. This phenomenon is termed recombination and explains the frequent observation that like begets like, but not exactly like.
A polyhybrid back-cross with two unrelated gene pairs exhibits a 1:1 ratio of phenotypes as in the mono-hybrid back-cross. It should be noted that despite dominance influence, an F1 back-cross with the P1 homozygous-recessive yields the homozygous-recessive phenotype short/late 25% of the time, and by the same logic, a back cross with the homozygous-dominant parent will yield the homozygous dominant phenotype tall/early 25% of the time. Again, the back-cross proves invaluable in determining the F1 and P1 genotypes. Since all four phenotypes of the back-cross progeny contain at least one each of both recessive genes or one each of both dominant genes, the back-cross phenotype is a direct representation of the four possible gametes produced by the F1 hybrid.
So far we have discussed inheritance of traits con trolled by discrete pairs of unrelated genes. Gene inter action is the control of a trait by two or more gene pairs. In this case genotype ratios will remain the same but phenotype ratios may be altered. Consider a hypothetical example where 2 dominant gene pairs Pp and Cc control late-season anthocyanin pigmentation (purple color) in Cannabis. If P is present alone, only the leaves of the plant (under the proper environmental stimulus) will exhibit accumulated anthocyanin pigment and turn a purple color. If C is present alone, the plant will remain green through out its life cycle despite environmental conditions. If both are present, however, the calyxes of the plant will also exhibit accumulated anthocyanin and turn purple as the leaves do. Let us assume for now that this may be a desirable trait in Cannabis flowers. What breeding techniques can be used to produce this trait?
First, two homozygous true-breeding ~1 types are crossed and the phenotype ratio of the F1 offspring is observed.
The phenotypes of the F2 progeny show a slightly altered phenotype ratio of 9:3:4 instead of the expected 9:3:3:1 for independently assorting traits. If P and C must both be present for any anthocyanin pigmentation in leaves or calyxes, then an even more distorted phenotype ratio of 9:7 will appear.
Two gene pairs may interact in varying ways to pro duce varying phenotype ratios. Suddenly, the simple laws of inheritance have become more complex, but the data may still be interpreted.

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Summary of Essential Points of Breeding
1 - The genotypes of plants are controlled by genes which are passed on unchanged from generation to generation.
2 - Genes occur in pairs, one from the gamete of the staminate parent and one from the gamete of the pistillate parent.
3 - When the members of a gene pair differ in their effect upon phenotype, the plant is termed hybrid or heterozygous.
4 - When the members of a pair of genes are equal in their effect upon phenotype, then they are termed true-breeding or homozygous.
5 - Pairs of genes controlling different phenotypic traits are (usually) inherited independently.
6 - Dominance relations and gene interaction can alter the phenotypic ratios of the F1, F2, and subsequent generations.

Polyploidy
Polyploidy is the condition of multiple sets of chromosomes within one cell. Cannabis has 20 chromosomes in the vegetative diploid (2n) condition. Triploid (3n) and tetraploid (4n) individuals have three or four sets of chromosomes and are termed polyploids. It is believed that the haploid condition of 10 chromosomes was likely derived by reduction from a higher (polyploid) ancestral number (Lewis, W. H. 1980). Polyploidy has not been shown to occur naturally in Cannabis; however, it may be induced artificially with colchicine treatments. Colchicine is a poisonous compound extracted from the roots of certain Colchicum species; it inhibits chromosome segregation to daughter cells and cell wall formation, resulting in larger than average daughter cells with multiple chromosome sets. The studies of H. E. Warmke et al. (1942-1944) seem to indicate that colchicine raised drug levels in Cannabis. It is unfortunate that Warmke was unaware of the actual psychoactive ingredients of Cannabis and was therefore unable to extract THC. His crude acetone extract and archaic techniques of bioassay using killifish and small freshwater crustaceans are far from conclusive. He was, however, able to produce both triploid and tetraploid strains of Cannabis with up to twice the potency of dip bid strains (in their ability to kill small aquatic organisms). The aim of his research was to "produce a strain of hemp with materially reduced marijuana content" and his results indicated that polyploidy raised the potency of Cannabis without any apparent increase in fiber quality or yield.
Warmke's work with polyploids shed light on the nature of sexual determination in Cannabis. He also illustrated that potency is genetically determined by creating a lower potency strain of hemp through selective breeding with low potency parents.
More recent research by A. I. Zhatov (1979) with fiber Cannabis showed that some economically valuable traits such as fiber quantity may be improved through polyploidy. Polyploids require more water and are usually more sensitive to changes in environment. Vegetative growth cycles are extended by up to 30-40% in polyploids. An extended vegetative period could delay the flowering of polyploid drug strains and interfere with the formation of floral clusters. It would be difficult to determine if cannabinoid levels had been raised by polyploidy if polyploid plants were not able to mature fully in the favorable part of the season when cannabinoid production is promoted by plentiful light and warm temperatures. Greenhouses and artificial lighting can be used to extend the season and test polyploid strains.
The height of tetraploid (4n) Cannabis in these experiments often exceeded the height of the original diploid plants by 25-30%. Tetraploids were intensely colored, with dark green leaves and stems and a well developed gross phenotype. Increased height and vigorous growth, as a rule, vanish in subsequent generations. Tetraploid plants often revert back to the diploid condition, making it difficult to support tetraploid populations. Frequent tests are performed to determine if ploidy is changing.
Triploid (3n) strains were formed with great difficulty by crossing artificially created tetraploids (4n) with dip bids (2n). Triploids proved to be inferior to both diploids and tetraploids in many cases.
De Pasquale et al. (1979) conducted experiments with Cannabis which was treated with 0.25% and 0.50% solutions of colchicine at the primary meristem seven days after generation. Treated plants were slightly taller and possessed slightly larger leaves than the controls, Anomalies in leaf growth occurred in 20% and 39%, respectively, of the surviving treated plants. In the first group (0.25%) cannabinoid levels were highest in the plants without anomalies, and in the second group (0.50%) cannabinoid levels were highest in plants with anomalies, Overall, treated plants showed a 166-250% increase in THC with respect to controls and a decrease of CBD (30-33%) and CBN (39-65%). CBD (cannabidiol) and CBN (cannabinol) are cannabinoids involved in the biosynthesis and degradation of THC. THC levels in the control plants were very low (less than 1%). Possibly colchicine or the resulting polyploidy interferes with cannabinoid biogenesis to favor THC. In treated plants with deformed leaf lamina, 90% of the cells are tetraploid (4n 40) and 10% diploid (2n 20). In treated plants without deformed lamina a few cells are tetraploid and the remainder are triploid or diploid.
The transformation of diploid plants to the tetraploid level inevitably results in the formation of a few plants with an unbalanced set of chromosomes (2n + 1, 2n - 1, etc.). These plants are called aneuploids. Aneuploids are inferior to polyploids in every economic respect. Aneuploid Cannabis is characterized by extremely small seeds. The weight of 1,000 seeds ranges from 7 to 9 grams (1/4 to 1/3 ounce). Under natural conditions diploid plants do not have such small seeds and average 14-19 grams (1/2-2/3 ounce) per 1,000 (Zhatov 1979).
Once again, little emphasis has been placed on the relationship between flower or resin production and polyploidy. Further research to determine the effect of polyploidy on these and other economically valuable traits of Cannabis is needed.
Colchicine is sold by laboratory supply houses, and breeders have used it to induce polyploidy in Cannabis. However, colchicine is poisonous, so special care is exercised by the breeder in any use of it. Many clandestine cultivators have started polyploid strains with colchicine. Except for changes in leaf shape and phyllotaxy, no out standing characteristics have developed in these strains and potency seems unaffected. However, none of the strains have been examined to determine if they are actually polyploid or if they were merely treated with colchicine to no effect. Seed treatment is the most effective and safest way to apply colchicine. * In this way, the entire plant growing from a colchicine-treated seed could be polyploid and if any colchicine exists at the end of the growing season the amount would be infinitesimal. Colchicine is nearly always lethal to Cannabis seeds, and in the treatment there is a very fine line between polyploidy and death. In other words, if 100 viable seeds are treated with colchicine and 40 of them germinate it is unlikely that the treatment induced polyploidy in any of the survivors. On the other hand, if 1,000 viable treated seeds give rise to 3 seedlings, the chances are better that they are polyploid since the treatment killed all of the seeds but those three. It is still necessary to determine if the offspring are actually polyploid by microscopic examination.
The work of Menzel (1964) presents us with a crude map of the chromosomes of Cannabis, Chromosomes 2-6 and 9 are distinguished by the length of each arm. Chromosome 1 is distinguished by a large knob on one end and a dark chromomere 1 micron from the knob. Chromosome 7 is extremely short and dense, and chromosome 8 is assumed to be the sex chromosome. In the future, chromosome *The word "safest" is used here as a relative term. Coichicine has received recent media attention as a dangerous poison and while these accounts are probably a bit too lurid, the real dangers of exposure to coichicine have not been fully researched. The possibility of bodily harm exists and this is multiplied when breeders inexperienced in handling toxins use colchicine. Seed treatment might be safer than spraying a grown plant but the safest method of all is to not use colchicine. mapping will enable us to picture the location of the genes influencing the phenotype of Cannabis. This will enable geneticists to determine and manipulate the important characteristics contained in the gene pool. For each trait the number of genes in control will be known, which chromosomes carry them, and where they are located along those chromosomes.

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All of the Cannabis grown in North America today originated in foreign lands. The diligence of our ancestors in their collection and sowing of seeds from superior plants, together with the forces of natural selection, have worked to create native strains with localized characteristics of resistance to pests, diseases, and weather conditions. In other words, they are adapted to particular niches in the ecosystem. This genetic diversity is nature's way of protecting a species. There is hardly a plant more flexible than Cannabis. As climate, diseases, and pests change, the strain evolves and selects new defenses, programmed into the genetic orders contained in each generation of seeds. Through the importation in recent times of fiber and drug Cannabis, a vast pool of genetic material has appeared in North America. Original fiber strains have escaped and become acclimatized (adapted to the environment), while domestic drug strains (from imported seeds) have, unfortunately, hybridized and acclimatized randomly, until many of the fine gene combinations of imported Cannabis have been lost.
Changes in agricultural techniques brought on by technological pressure, greed, and full-scale eradication programs have altered the selective pressures influencing Cannabis genetics. Large shipments of inferior Cannabis containing poorly selected seeds are appearing in North America and elsewhere, the result of attempts by growers and smugglers to supply an ever increasing market for marijuana. Older varieties of Cannabis, associated with long standing cultural patterns, may contain genes not found in the newer commercial varieties. As these older varieties and their corresponding cultures become extinct, this genetic information could be lost forever. The increasing popularity of Cannabis and the requirements of agricultural technology will call for uniform hybrid races that are likely to displace primitive populations worldwide.
Limitation of genetic diversity is certain to result from concerted inbreeding for uniformity. Should inbred Cannabis be attacked by some previously unknown pest or disease, this genetic uniformity could prove disastrous due to potentially resistant diverse genotypes having been dropped from the population. If this genetic complement of resistance cannot be reclaimed from primitive parental material, resistance cannot be introduced into the ravaged population. There may also be currently unrecognized favorable traits which could be irretrievably dropped from the Cannabis gene pool. Human intervention can create new phenotypes by selecting and recombining existing genetic variety, but only nature can create variety in the gene pool itself, through the slow process of random mutation.
This does not mean that importation of seed and selective hybridization are always detrimental. Indeed these principles are often the key to crop improvement, but only when applied knowledgeably and cautiously. The rapid search for improvements must not jeopardize the pool of original genetic information on which adaptation relies. At this time, the future of Cannabis lies in government and clandestine collections. These collections are often inadequate, poorly selected and badly maintained. Indeed, the United Nations Cannabis collection used as the primary seed stock for worldwide governmental research is depleted and spoiled.
Several steps must be taken to preserve our vanishing genetic resources, and action must be immediate:
• Seeds and pollen should be collected directly from reliable and knowledgeable sources. Government seizures and smuggled shipments are seldom reliable seed sources. The characteristics of both parents must be known; consequently, mixed bales of randomly pollinated marijuana are not suitable seed sources, even if the exact origin of the sample is certain. Direct contact should be made with the farmer-breeder responsible for carrying on the breeding traditions that have produced the sample. Accurate records of every possible parameter of growth must be kept with carefully stored triplicate sets of seeds.
• Since Cannabis seeds do not remain viable forever, even under the best storage conditions, seed samples should he replenished every third year. Collections should be planted in conditions as similar as possible to their original niche and allowed to reproduce freely to minimize natural and artificial selection of genes and ensure the preservation of the entire gene pool. Half of the original seed collection should be retained until the viability of further generations is confirmed, and to provide parental material for comparison and back-crossing. Phenotypic data about these subsequent generations should be carefully recorded to aid in understanding the genotypes contained in the collection. Favorable traits of each strain should be characterized and catalogued.
• It is possible that in the future, Cannabis cultivation for resale, or even personal use, may be legal but only for approved, patented strains. Special caution would be needed to preserve variety in the gene pool should the patenting of Cannabis strains become a reality.
• Favorable traits must be carefully integrated into existing strains.
The task outlined above is not an easy one, given the current legal restrictions on the collection of Cannabis seed. In spite of this, the conscientious cultivator is making a contribution toward preserving and improving the genetics of this interesting plant.
Even if a grower has no desire to attempt crop improvement, successful strains have to be protected so they do not degenerate and can be reproduced if lost. Left to the selective pressures of an introduced environment, most drug strains will degenerate and lose potency as they acclimatize to the new conditions. Let me cite an example of a typical grower with good intentions.
A grower in northern latitudes selected an ideal spot to grow a crop and prepared the soil well. Seeds were selected from the best floral clusters of several strains avail able over the past few years, both imported and domestic. Nearly all of the staminate plants were removed as they matured and a nearly seedless crop of beautiful plants resulted. After careful consideration, the few seeds from accidental pollination of the best flowers were kept for the following season, These seeds produced even bigger and better plants than the year before and seed collection was performed as before. The third season, most of the plants were not as large or desirable as the second season, but there were many good individuals. Seed collection and cultivation the fourth season resulted in plants inferior even to the first crop, and this trend continued year after year. What went wrong? The grower collected seed from the best plants each year and grew them under the same conditions. The crop improved the first year. Why did the strain degenerate?
This example illustrates the unconscious selection for undesirable traits. The hypothetical cultivator began well by selecting the best seeds available and growing them properly. The seeds selected for the second season resulted from random hybrid pollinations by early-flowering or overlooked staminate plants and by hermaphrodite pistil late plants. Many of these random pollen-parents may be undesirable for breeding since they may pass on tendencies toward premature maturation, retarded maturation, or hermaphrodism. However, the collected hybrid seeds pro duce, on the average, larger and more desirable offspring than the first season. This condition is called hybrid vigor and results from the hybrid crossing of two diverse gene pools. The tendency is for many of the dominant characteristics from both parents to be transmitted to the F1 off spring, resulting in particularly large and vigorous plants. This increased vigor due to recombination of dominant genes often raises the cannabinoid level of the F1 offspring, but hybridization also opens up the possibility that undesirable (usually recessive) genes may form pairs and express their characteristics in the F2 offspring. Hybrid vigor may also mask inferior qualities due to abnormally rapid growth. During the second season, random pollinations again accounted for a few seeds and these were collected. This selection draws on a huge gene pool and the possible F2 combinations are tremendous. By the third season the gene pool is tending toward early-maturing plants that are acclimatized to their new conditions instead of the drug-producing conditions of their native environment. These acclimatized members of the third crop have a higher chance of maturing viable seeds than the parental types, and random pollinations will again increase the numbers of acclimatized individuals, and thereby increase the chance that undesirable characteristics associated with acclimatization will be transmitted to the next F2 generation. This effect is compounded from generation to generation and finally results in a fully acclimatized weed strain of little drug value.
With some care the breeder can avoid these hidden dangers of unconscious selection. Definite goals are vital to progress in breeding Cannabis. What qualities are desired in a strain that it does not already exhibit? What characteristics does a strain exhibit that are unfavorable and should be bred out? Answers to these questions suggest goals for breeding. In addition to a basic knowledge of Cannabis botany, propagation, and genetics, the successful breeder also becomes aware of the most minute differences and similarities in phenotype. A sensitive rapport is established between breeder and plants and at the same time strict guidelines are followed. A simplified explanation of the time-tested principles of plant breeding shows how this works in practice.

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Selection is the first and most important step in the breeding of any plant. The work of the great breeder and plant wizard Luther Burbank stands as a beacon to breeders of exotic strains. His success in improving hundreds of flower, fruit, and vegetable crops was the result of his meticulous selection of parents from hundreds of thou sands of seedlings and adults from the world over.
Bear in mind that in the production of any new plant, selection plays the all-important part. First, one must get clearly in mind the kind of plant he wants, then breed and select to that end, always choosing through a series of years the plants which are approaching nearest the ideal, and rejecting all others.
• Luther Burbank (in James, 1964)
Proper selection of prospective parents is only possible if the breeder is familiar with the variable characteristics of Cannabis that may be genetically controlled, has a way to accurately measure these variations, and has established goals for improving these characteristics by selective breeding. A detailed list of variable traits of Cannabis, including parameters of variation for each trait and comments pertaining to selective breeding for or against it, are found at the end of this chapter. By selecting against unfavorable traits while selecting for favorable ones, the unconscious breeding of poor strains is avoided.
The most important part of Burbank's message on selection tells breeders to choose the plants "which are approaching nearest the ideal," and REJECT ALL OTHERS! Random pollinations do not allow the control needed to reject the undesirable parents. Any staminate plant that survives detection and roguing (removal from the population), or any stray staminate branch on a pistillate her maphrodite may become a pollen parent for the next generation. Pollination must be controlled so that only the pollen- and seed-parents that have been carefully selected for favorable traits will give rise to the next generation.
Selection is greatly improved if one has a large sample to choose from! The best plant picked from a group of 10 has far less chance of being significantly different from its fellow seedlings than the best plant selected from a sample of 100,000. Burbank often made his initial selections of parents from samples of up to 500,000 seedlings. Difficulties arise for many breeders because they lack the space to keep enough examples of each strain to allow a significant selection. A Cannabis breeder's goals are restricted by the amount of space available. Formulating a well defined goal lowers the number of individuals needed to perform effective crosses. Another technique used by breeders since the time of Burbank is to make early selections. Seedling plants take up much less space than adults. Thousands of seeds can be germinated in a flat. A flat takes up the same space as a hundred 10-centimeter (4-inch) sprouts or six-teen 30-centimeter (12-inch) seedlings or one 60-centimeter (24-inch) juvenile. An adult plant can easily take up as much space as a hundred flats. Simple arithmetic shows that as many as 10,000 sprouts can be screened in the space required by each mature plant, provided enough seeds are available. Seeds of rare strains are quite valuable and exotic; however, careful selection applied to thousands of individuals, even of such common strains as those from Colombia or Mexico, may produce better offspring than plants from a rare strain where there is little or no opportunity for selection after germination. This does not mean that rare strains are not valuable, but careful selection is even more important to successful breeding. The random pollinations that produce the seeds in most imported marijuana assure a hybrid condition which results in great seed ling diversity. Distinctive plants are not hard to discover if the seedling sample is large enough.
Traits considered desirable when breeding Cannabis often involve the yield and quality of the final product, but these characteristics can only be accurately measured after the plant has been harvested and long after it is possible to select or breed it. Early seedling selection, therefore, only works for the most basic traits. These are selected first, and later selections focus on the most desirable characteristics exhibited by juvenile or adult plants. Early traits often give clues to mature phenotypic expression, and criteria for effective early seedling selection are easy to establish. As an example, particularly tall and thin seedlings might prove to be good parents for pulp or fiber production, while seed lings of short internode length and compound branching may be more suitable for flower production. However, many important traits to be selected for in Cannabis floral clusters cannot be judged until long after the parents are gone, so many crosses are made early and selection of seeds made at a later date.
Hybridization is the process of mixing differing gene pools to produce offspring of great genetic variation from which distinctive individuals can be selected. The wind performs random hybridization in nature. Under cultivation, breeders take over to produce specific, controlled hybrids. This process is also known as cross-pollination, cross-fertilization, or simply crossing. If seeds result, they will produce hybrid offspring exhibiting some characteristics from each parent.
Large amounts of hybrid seed are most easily produced by planting two strains side by side, removing the staininate plants of the seed strain, and allowing nature to take its course. Pollen- or seed-sterile strains could be developed for the production of large amounts of hybrid seed without the labor of thinning; however, genes for sterility are rare. It is important to remember that parental weak nesses are transmitted to offspring as well as strengths. Because of this, the most vigorous, healthy plants are al ways used for hybrid crosses.
Also, sports (plants or parts of plants carrying and expressing spontaneous mutations) most easily transmit mutant genes to the offspring if they are used as pollen parents. If the parents represent diverse gene pools, hybrid vigor results, because dominant genes tend to carry valuable traits and the differing dominant genes inherited from each parent mask recessive traits inherited from the other. This gives rise to particularly large, healthy individuals. To increase hybrid vigor in offspring, parents of different geo graphic origins are selected since they will probably represent more diverse gene pools.
Occasionally hybrid offspring will prove inferior to both parents, but the first generation may still contain recessive genes for a favorable characteristic seen in a parent if the parent was homozygous for that trait. First generation (F1) hybrids are therefore inbred to allow recessive genes to recombine and express the desired parental trait. Many breeders stop with the first cross and never realize the genetic potential of their strain. They fail to produce an F2 generation by crossing or self-pollinating F1 offspring. Since most domestic Cannabis strains are F1 hybrids for many characteristics, great diversity and recessive recombination can result from inbreeding domestic hybrid strains. In this way the breeding of the F1 hybrids has already been accomplished, and a year is saved by going directly to F2 hybrids. These F2 hybrids are more likely to express recessive parental traits. From the F2 hybrid generation selections can be made for parents which are used to start new true-breeding strains. Indeed, F2 hybrids might appear with more extreme characteristics than either of the P~ parents. (For example, P1 high-THC X P1 low-THC yields F1 hybrids of intermediate THC content. Selfing the F1 yields F2 hybrids, of both P1 [high and low THC] phenotypes, inter mediate F1 phenotypes, and extra-high THC as well as extra-low THC phenotypes.)
Also, as a result of gene recombination, F1 hybrids are not true-breeding and must be reproduced from the original parental strains. When breeders create hybrids they try to produce enough seeds to last for several successive years of cultivation, After initial field tests, undesirable hybrid seeds are destroyed and desirable hybrid seeds stored for later use. If hybrids are to be reproduced, a clone is saved from each parental plant to preserve original parental genes.
Back-crossing is another technique used to produce offspring with reinforced parental characteristics. In this case, a cross is made between one of the F~ or subsequent offspring and either of the parents expressing the desired trait. Once again this provides a chance for recombination and possible expression of the selected parental trait. Back-crossing is a valuable way of producing new strains, but it is often difficult because Cannabis is an annual, so special care is taken to save parental stock for back-crossing the following year. Indoor lighting or greenhouses can be used to protect breeding stock from winter weather. In tropical areas plants may live outside all year. In addition to saving particular parents, a successful breeder always saves many seeds from the original P1 group that produced the valuable characteristic so that other P1 plants also exhibiting the characteristic can be grown and selected for back-crossing at a later time.