Marijuana Botany An Advanced Study: The Propagation and Breeding of Distinctive Cannabis
by Robert Connell Clarke
FOREWORD vii
INTRODUCTION ix
PREFACE xiii
CHAPTER 1 Sinsemilla Life Cycle of Cannabis
CHAPTER 2 Propagation of Cannabis 13
CHAPTER 3 Genetics and Breeding of f Cannabis 49
CHAPTER 4 Maturation and Harvesting of Cannabis 129
Introduction
Cannabis, commonly known in the United States as marijuana, is a wondrous plant an ancient plant and an ally of humanity for over ten thousand years. The pro- found impact Cannabis has had on the development and spread of civilization and conversely, the profound effects we've had on the plant's evolution are just now being discovered.
Cannabis was one of the earliest and most important plants placed under cultivation by prehistoric Asian peoples. Virtually every part of the plant is usable. From the stem comes hemp, a very long, strong fiber used to make rope, cloth, and paper renowned for durability. The dried leaves and flowers become the euphoriant, marijuana, and along with the root, are also used for numerous medi- cines. The seeds were a staple food in ancient China, one of their major "grains." Cannabis seeds are somewhat unpala- table and are now cultivated mainly for oil or for animal feed. The oil is similar to linseed and is used for paint and varnish making, fuel, and lubrication.
Cultivated Cannabis quickly spread westward from its native Asia and by Roman times hemp was grown in almost every European country. In Africa, marijuana was the pre- ferred product, smoked both ritually and for pleasure. When the first colonists came to America they, quite naturally, brought hemp seed with them for rope and home-spun cloth. Hemp fiber for ships' rigging was so im- portant to the English navy that colonists were paid boun- ties to grow hemp and in some states, penalties were imposed on those who didn't. Prior to the Civil War, the hemp industry was second only to cotton in the South.
Today, Cannabis grows around the world and is, in fact, considered the most widely distributed of all culti- vated plants, a testimony to the plant's tenacity and adapt- able nature as well as to its usefulness and economic value. Unlike many plants, Cannabis never lost the ability to flourish without human help despite, perhaps, six millennia of cultivation.
Whenever ecological circumstances permit, the plants readily "escape" cultivation by becoming weedy and estab- lishing "wild" populations. Weedy Cannabis, descended from the bygone hemp industry, grows in all but the more arid areas of the United States. Unfortunately, these weeds usually make a very poor grade marijuana.
Such an adaptable plant, brought to a wide range of environments, and cultivated and bred for a multitude of products, understandably evolved a great number of dis- tinctive strains or varieties, each one uniquely suited to local needs and growing conditions. Many of these varieties may be lost through extinction and hybridization unless a concerted effort is made to preserve them. This book pro- vides the basis for such an undertaking.
There are likely more varieties of marijuana being grown or held as seeds in this country than any other. While traditional marijuana growers in Asia and Africa, typically, grow the same, single variety their forebears grew, American growers seek and embrace varieties from all parts of the world. Very potent, early-flowering varieties are especially prized because they can complete maturation even in the northernmost states. The Cannabis stock in the United Nations seed bank is at best, depleted and in dis- array. American growers are in the best position to prevent further loss of valuable varieties by saving, cataloguing, and propagating their seeds.
Marijuana Botany-the Propagation and Breeding of Distinctive Cannabis is an important and most welcome book. Its main thrust is the presentation of the scientific and horticultural principles, along with their practical ap- plications, necessary for the breeding and propagation of Cannabis and in particular, marijuana. This book will appeal not only to the professional researcher, but to the mari- juana enthusiast or anyone with an eye to the future of Cannabis products.
To marijuana growers who wish to improve or up- grade their varieties, the book is an invaluable reference. Basic theories and practices for breeding pure stock or hybrids, cloning, grafting, or breeding to improve quali ties such as potency or yield, are covered in a clear, easy- to-follow text which is liberally complemented with draw- ings, charts, and graphs by the author. Rob Clarke's drawings reflect his love of Cannabis. They sensitively capture the plant's elegance and ever-changing beauty while being always informative and accurately rendered.
The reader not familiar with botanical terms need not be intimidated by a quick glance at the text. All terms are defined when they are introduced and there is also a glos- sary with definitions geared to usage. Anyone familiar with the plant will easily adopt the botanical terms.
Years from now, many a marijuana smoker may un- knowingly be indebted to this book for the exotic varieties that will be preserved and new ones that will be developed. Growers will especially appreciate the expert information on marijuana propagation and breeding so attractively and clearly presented.
Mel Frank author, Marijuana Growers' Guide
Preface
Turn again our captivity, 0 Lord, as the streams in the dry land. They that sow in tears shall reap in joy. He that goeth forth and weepeth, bearing precious seed, shall doubtless come again with rejoicing, bringing his sheaves with him. -Psalms 126: 4-6
Cannabis is one of the world's oldest cultivated plants. Currently, however, Cannabis cultivation and use is illegal or legally restricted around the globe. Despite constant official control, Cannabis cultivation and use has spread to every continent and nearly every nation. Cultivated and wild Cannabis flourishes in temperate and tropical climates worldwide. Three hundred million users form a strong un- dercurrent beneath the flowing tide of eradication. To judge by increasing official awareness of the economic potentials of Cannabis, legalization seems inevitable al- though slow. Yet as Cannabis faces eventual legalization it is threatened by extinction. Government-sanctioned and -supported spraying with herbicides and other forms of eradication have chased ancient Cannabis strains from their native homes.
Cannabis has great potential for many commercial uses. According to a recent survey of available research by Turner, Elsohly and Boeren (1980) of the Research Insti- tute of Pharmaceutical Sciences at the University of Missis- sippi, Cannabis contains 421 known compounds, and new ones are constantly being discovered and reported. Without further understanding of the potentials of Cannabis as a source of fiber, fuel, food, industrial chemicals and medi- cine it seems thoughtless to support eradication campaigns.
World politics also threaten Cannabis. Rural Cannabis farming cultures of the Middle East, Southeast Asia, Cen tral America and Mrica face political unrest and open aggression. Cannabis seeds cannot be stored forever. If they are not planted and reproduced each year a strain could be lost. Whales, big cats, and redwoods are all protected in preserves established by national and international laws. Plans must also be implemented to protect Cannabis cul- tures and rare strains from certain extinction.
Agribusiness is excited at the prospect of supplying America's 20 million Cannabis users with domestically grown commercial marijuana. As a result, development of uniform patented hybrid strains by multinational agricul- tural firms is inevitable. The morality of plant patent laws has been challenged for years. For humans to recombine and then patent the genetic material of another living or- ganism, especially at the expense of the original organism, certainly offends the moral sense of many concerned citi- zens. Does the slight recombination of a plant's genetic material by a breeder give him the right to own that organ- ism and its offspring? Despite public resistance voiced by conservation groups, the Plant Variety Protection Act of 1970 was passed and currently allows the patenting of 224 vegetable crops. New amendments could grant patent holders exclusive rights for 18 years to distribute, import, export and use for breeding purposes their newly devel- oped strains. Similar conventions worldwide could further threaten genetic resources. Should patented varieties of Cannabis become reality it might be illegal to grow any strain other than a patented variety, especially for food or medicinal uses. Limitations could also be imposed such that only low-THC strains would be patentable. This could lead to restrictions on small-scale growing of Cannabis; commercial growers could not take the chance of stray pollinations from private plots harming a valuable seed crop. Proponents of plant patenting claim that patents will encourage the development of new varieties. In fact, patent laws encourage the spread of uniform strains devoid of the genetic diversity which allows improvements. Patent laws have also fostered intense competition between breeders and the suppression of research results which if made pub- lic could speed crop improvement. A handful of large cor- porations hold the vast majority of plant patents. These conditions will make it impossible for cultivators of native strains to compete with agribusiness and could lead to the further extinction of native strains now surviving on small farms in North America and Europe. Plant improvement in itself presents no threat to genetic reserves. However, the support and spread of improved strains by large cor- porations could prove disastrous.
Like most major crops, Cannabis originated outside North America in still-primitive areas of the world. Thou- sands of years ago humans began to gather seeds from wild Cannabis and grow them in fields alongside the first culti- vated food crops. Seeds from the best plants were saved for planting the following season. Cannabis was spread by no- madic tribes and by trade between cultures until it now ap- pears in both cultivated and escaped forms in many nations. The pressures of human and natural selection have resulted in many distinct strains adapted to unique niches within the ecosystem. Thus, individual Cannabis strains possess unique gene pools containing great potential diversity. In this diversity lies the strength of genetic inheritance. From diverse gene pools breeders extract the desirable traits in- corporated into new varieties. Nature also calls on the gene pool to ensure that a strain will survive. As climate changes and stronger pests and diseases appear, Cannabis evolves new adaptations and defenses.
Modern agriculture is already striving to change this natural system. When Cannabis is legalized, the breeding and marketing of improved varieties for commercial agri- culture is certain. Most of the areas suitable for commercial Cannabis cultivation already harbor their own native strains. Improved strains with an adaptive edge will follow in the wake of commercial agriculture and replace rare native strains in foreign fields. Native strains will hybridize with introduced strains through wind-borne pollen dispersal and some genes will be squeezed from the gene pool.
Herein lies extreme danger! Since each strain of Can- nabis is genetically unique and contains at least a few genes not found in other strains, if a strain becomes extinct the unique genes are lost forever. Should genetic weaknesses arise from excessive inbreeding of commercial strains, new varieties might not be resistant to a previously unrecog- nized environmental threat. A disease could spread rapidly and wipe out entire fields simultaneously. Widespread crop failure would result in great financial loss to the farmer and possible extinction of entire strains.
In 1970, to the horror of American farmers and plant breeders, Southern corn leaf-blight (Helm in thosporium maydis) spread quickly and unexpectedly throughout corn crops and caught farmers off guard with no defense. H. maydis is a fungus which causes minor rot and damage in corn and had previously had no economic impact. How- ever, in 1969 a virulent mutant strain of the fungus ap- peared in Illinois, and by the end of the following season its wind-borne spores had spread and blighted crops from the Great Lakes to the Gulf of Mexico. Approximately 15% of America's corn crop was destroyed. In some states over half the crop was lost.
Fortunately the only fields badly infected were those containing strains descended from parents of what corn breeders called "the Texas strain." Plants descended from parents of previously developed strains were only slightly infected. The discovery and spread of the Texas strain had revolutionized the corn industry. Since pollen from this strain is sterile, female plants do not have to be detasseled by hand or machine, saving farmers millions of dollars annually. Unknown to corn breeders, hidden in this im- proved strain was an extreme vulnerability to the mutant leaf-blight fungus.
Total disaster was avoided by the around-the clock efforts of plant breeders to develop a commercial strain from other than Texas plants. It still took three years to develop and reproduce enough resistant seed to supply all who needed it. We are also fortunate that corn breeders could rise to the challenge and had maintained seed re- serves for breeding. If patented hybrid strains of Cannabis are produced and gain popularity, the same situation could arise. Many pathogens are known to infect Cannabis and any one of them has the potential to reach epidemic pro- portions in a genetically uniform crop. We can not and should not stop plant improvement programs and the use of hybrid strains. However, we should provide a reserve of genetic material in case it is required in the future. Breeders can only combat future problems by relying on primitive gene pools contained in native strains. If native gene pools have been squeezed out by competition from patented commercial hybrids than the breeder is helpless. The forces of mutation and natural selection take thousands of years to modify gene pools, while a Cannabis blight could spread like wildfire.
As Cannabis conservationists, we must fight the further amendment of plant patent laws to include Cannabis, and initiate programs immediately to collect, catalogue, and propagate vanishing strains. Cannabis preserves are needed where each strain can be freely cultivated in areas resemb- ling native habitats. This will help reduce the selective pressure of an introduced environment, and preserve the genetic integrity of each strain. Presently such a program is far from becoming a reality and rare strains are vanishing faster than they can be saved. Only a handful of dedicated researchers, cultivators, and conservationists are concerned with the genetic fate of Cannabis. It is tragic that a plant with such promise should be caught up in an age when ex- tinction at the hands of humans is commonplace. Respon- sibility is left with the few who will have the sensitivity to end genocide and the foresight to preserve Cannabis for future generations.
Marijuana Botany presents the scientific knowledge and propagation techniques used to preserve and multiply vanishing Cannabis strains. Also included is information concerning Cannabis genetics and breeding used to begin plant improvement programs. It is up to the individual to use this information thoughtfully and responsibly.
Chapter 1 - Sinsemilla Life Cycle of Cannabis
Cannabis is a tall, erect, annual herb. Provided with an open sunny environment, light well-drained composted soil, and ample irrigation, Cannabis can grow to a height of 6 meters (about 20 feet) in a 4-6 month growing season. Exposed river banks, mead- ows, and agricultural lands are ideal habi- tats for Cannabis since all offer good sun- light. In this example an imported seed from Thailand is grown without pruning and becomes a large female plant. A cross with a cutting from a male plant of Mexi- can origin results in hybrid seed which is stored for later planting. This example is representative of the outdoor growth of Cannabis in temperate climates.
Seeds are planted in the spring and usually germinate in 3 to 7 days. The seed- ling emerges from the ground by the straightening of the hypocotyl (embryonic stem). The cotyledons (seed leaves) are slightly unequal in size, narrowed to the base and rounded or blunt to the tip.
The hypocotyl ranges from 1 to 10 centimeters (1A to 3 inches) in length. About 10 centimeters or less above the cotyledons, the first true leaves arise, a pair of oppo- sitely oriented single leaflets each with a distinct petiole (leaf stem) rotated one- quarter turn from the cotyledons. Subse- quent pairs of leaves arise in opposite formation and a variously shaped leaf se- quence develops with the second pair of leaves having 3 leaflets, the third 5 and so on up to 11 leaflets. Occasionally the first pair of leaves will have 3 leaflets each rather than 1 and the second pair, 5 leaflets each.
If a plant is not crowded, limbs will grow from small buds (located at the inter- section of petioles) along the main stem. Each sinsemilla (seedless drug Cannabis) plant is provided with plenty of room to grow long axial limbs and extensive fine roots to increase floral production. Under favorable conditions Cannabis grows up to 7 centimeters (21A inches) a day in height during the long days of summer.
Cannabis shows a dual response to daylength; during the first two to three months of growth it responds to increasing daylength with more vigorous growth, but in the same season the plant requires shorter days to flower and complete its life cycle. LIFE CYCLE OF CANNABIS I Juvenile Stage
Cannabis flowers when exposed to a critical daylength which varies with the strain. Critical daylength applies only to plants which fail to flower under continu- ous illumination, since those which flower under continuous illumination have no criti- cal daylength. Most strains have an absolute requirement of inductive photoperiods (short days or long nights) to induce fertile flowering and less than this will result in the formation of undifferentiated primor- dia (unformed flowers) only.
The time taken to form primordia varies with the length of the inductive pho- - toperiod. Given 10 hours per day of light a strain may only take 10 days to flower, whereas if given 16 hours per day it may take up to 90 days. Inductive photoperiods of less than 8 hours per day do not seem to accelerate primordia formation. Dark (night) cycles must be uninterrupted to in- duce flowering (see appendix).
Cannabis is a dioecious plant, which means that the male and female flowers develop on separate plants, although mono- ecious examples with both sexes on one plant are found. The development of branches containing flowering organs varies greatly between males and females: the male flowers hang in long, loose, multi- branched, clustered limbs up to 30 centi- meters (12 inches) long, while the female flowers are tightly crowded between small leaves.
Note: Female Cannabis flowers and plants will be referred to as pistillate and male flowers and plants will be referred to as staminate in the remainder of this text. This convention is more accurate and makes examples of complex aberrant sexuality easier to understand.
The first sign of flowering in Cannabis is the appearance of undifferentiated flower primordia along the main stem at the nodes (intersections) of the petiole, behind the stipule (leaf spur). In the prefloral phase, the sexes of Cannabis are indistinguishable except for general trends in shape.
When the primordia first appear they are undifferentiated sexually, but soon the males can be identified by their curved claw shape, soon followed by the differen- tiation of round pointed flower buds having five radial segments. The females are recog- nized by the enlargement of a symmetrical tubular calyx (floral sheath). They are easier to recognize at a young age than male pri- mordia. The first female calyxes tend to lack paired pistils (pollen-catching appen- dages) though initial male flowers often mature and shed viable pollen. In some in- dividuals, especially hybrids, small non- flowering limbs will form at the nodes and are often confused with male primordia. Cultivators wait until actual flowers form to positively determine the sex of Cannabis
The female plants tend to be shorter and have more branches than the male. Female plants are leafy to the top with many leaves surrounding the flowers, while male plants have fewer leaves near the top with few if any leaves along the extended flowering limbs.
*The term pistil has developed a special meaning with respect to Cannabis which differs slightly from the precise botanical definition. This has come about mainly from the large number of culti- vators who have casual knowledge of plant anatomy but an intense interest in the reproduction of Can- nabis. The precise definition of pistil refers to the combination of ovary, style and stigma. In the more informal usage, pistil refers to the fused style and stigma. The informal sense is used throughout the book since it has become common practice among Cannabis cultivators.
The female flowers appear as two long white, yellow, or pink pistils protruding from the fold of a very thin membranous calyx. The calyx is covered with resin- exuding glandular trichomes (hairs). Pistil- late flowers are borne in pairs at the nodes one on each side of the petiole behind the stipule of bracts (reduced leaves) which conceal the flowers. The calyx measures 2 to 6 millimeters in length and is closely applied to, and completely contains, the ovary.
In male flowers, five petals (approxi- mately 5 millimeters, or 3/16 inch, long) make up the calyx and may be yellow, white, or green in color. They hang down, and five stamens (approximately 5 milli- meters long) emerge, consisting of slender anthers (pollen sacs), splitting upwards from the tip and suspended on thin filaments. The exterior surface of the staminate calyx is covered with non-glandular trichomes. The pollen grains are nearly spherical slightly yellow, and 25 to 30 microns (p) in diameter. The surface is smooth and ex- hibits 2 to 4 germ pores.
Before the start of flowering, the phyllotaxy (leaf arrangement) reverses and the number of leaflets per leaf decreases until a small single leaflet appears below each pair of calyxes. The phyllotaxy also changes from decussate (opposite) to alter- nate (staggered) and usually remains alter- nate throughout the floral stages regardless of sexual type.
The differences in flowering patterns of male and female plants are expressed in many ways. Soon after dehiscence (pollen shedding) the staminate plant dies, while the pistillate plant may mature up to five months after viable flowers are formed if little or no fertilization occurs. Compared with pistillate plants, staminate plants show a more rapid increase in height and a more rapid decrease in leaf size to the bracts which accompany the flowers. Staminate
plants tend to flower up to one month ear- lier than pistillate plants; however, pistillate plants often differentiate primordia one to two weeks before staminate plants.
Many factors contribute to determin- ing the sexuality of a flowering Cannabis plant. Under average conditions with a nor- mal inductive photoperiod, Cannabis will bloom and produce approximately equal numbers of pure staminate and pure pistil- late plants with a few hermaphrodites (both sexes on the same plant). Under conditions of extreme stress, such as nutrient excess or deficiency, mutilation, and altered light cycles, populations have been shown to de- part greatly from the expected one-to-one staminate to pistillate ratio.
Just prior to dehiscence, the pollen nucleus divides to produce a small repro- ductive cell accompanied by a large vegeta- tive cell, both of which are contained within the mature...
Lexian