Chap 3: Genetics and Breeding of Cannabis Part 3/3

Chapter 3 - Genetics and Breeding of Cannabis


6. Gross Phenotypes of Cannabis Strains

The gross phenotype or general growth form is deter mined by size, root production, branching pattern, sex, maturation, and floral characteristics. Most imported varieties have characteristic gross phenotypes although there tend to be occasional rare examples of almost every phenotype in nearly every variety. This indicates the complexity of genetic control determining gross phenotype. Hybrid crosses between imported pure varieties were the beginning of nearly every domestic strain of Cannabis. In hybrid crosses, some dominant characteristics from each parental variety are exhibited in various combinations by the F1 offspring. Nearly all of the offspring will resemble both parents and very few will resemble only one parent. This sounds like it is saying a lot, but this F1 hybrid generation is far from true-breeding and the subsequent F2 generation will exhibit great variation, tending to look more like one or the other of the original imported parental varieties, and will also exhibit recessive traits not apparent in either of the original parents. If the F1 offspring are desirable plants it will be difficult to continue the hybrid traits in subsequent generations. Enough of the original F1 hybrid seeds are produced so they may be used year after year to pro-duce uniform crops of desirable plants.

Phenotypes and Characteristics

of Imported Strains

Following is a list of gross phenotypes and characteristics for many imported strains of Cannabis.

1. Fiber Strain Gross Phenotypes (hemp types)

2. Drug Strain Gross Phenotypes

a) Colombia - highland, lowland (marijuana)

b) Congo - (marijuana)

c) Hindu Kush - Afghanistan and Pakistan (hashish)

d) Southern India - (ganja marijuana)

e) Jamaica - Carribean hybrids

f) Kenya - Kisumu (dagga marijuana)

g) Lebanon - (hashish)

h) Malawi, Africa - Lake Nyasa (dagga marijuana)

i) Mexico - Michoacan, Oaxaca, Guerrero (marijuana)

j) Morocco - Rif mountains (kif marijuana and hashish)

h) Nepal - wild (ganja marijuana and hashish)

1) Russian - ruderalis (uncultivated)

m) South Africa - (dagga marijuana)

n) Southeast Asia - Cambodia, Laos, Thailand, Vietnam (ganja marijuana)

3. Hybrid Drug Phenotypes

a) Creeper Phenotype

b) Huge Upright Phenotype

In general the F1 and F2 pure-bred offspring of these imported varieties are more similar to each other than they are to other varieties and they are termed pure strains.

However, it should be remembered that these are average. Gross phenotypes and recessive variations within each trait will occur. In addition, these representations are based on unpruned plants growing in ideal conditions and stress will alter the gross phenotype. Also, the protective environment of a greenhouse tends to obscure the difference between different strains. This section presents information that is used in the selection of pure strains for breeding.

1. Fiber Strain Gross Phenotypes Fiber strains are characterized as tall, rapidly maturing, limbless plants which are often monoecious. This growth habit has been selected by generations of fiber-producing farmers to facilitate forming long fibers through even growth and maturation. Monoecious strains mature more evenly than dioecious strains, and fiber crops are usually not grown long enough to set seed which interferes with fiber production. Most varieties of fiber Cannabis originate in the northern temperate climates of Europe, Japan, China and North America. Several strains have been selected from the prime hemp growing areas and offered commercially over the last fifty years in both Europe and America. Escaped fiber strains of the midwestern United States are usually tall, skinny, relatively poorly branched, weakly flowered, and low in cannabinoid production. They represent an escaped race of Cannabis sativa hemp. Most fiber strains contain CBD as the primary cannabinoid and little if any THC.


2. Drug Strain Gross Phenotypes Drug strains are characterized by Delta1-THC as the primary cannabinoid, with low levels of other accessory cannabinoids such as THCV, CBD, CBC, and CBN. This results from selective breeding for high potency or natural selection in niches where Delta1-THC biosynthesis favors survival.

a) Colombia - (0 to 10 north latitude)

Colombian Cannabis originally could be divided into two basic strains: one from the low-altitude humid coastal areas along the Atlantic near Panama, and the other from the more arid mountain areas inland from Santa Marta. More recently, new areas of cultivation in the interior plateau of southern central Colombia and the highland valleys stretching southward from the Atlantic coast have become the primary areas of commercial export Cannabis cultivation. Until recent years high quality Cannabis was available through the black market from both coastal and highland Colombia. Cannabis was introduced to Colombia just over 100 years ago, and its cultivation is deeply rooted in tradition. Cultivation techniques often involve transplanting of selected seedlings and other individual attention. The production of "la mona amarilla" or gold buds is achieved by girdling or removing a strip of bark from the main stem of a nearly mature plant, thereby restricting the flow of water, nutrients, and plant products. Over several days the leaves dry up and fall off as the flowers slowly die and turn yellow. This produces the highly prized "Colombian gold" so prevalent in the early to middle 1970s (Partridge 1973). Trade names such as "punta roja" (red tips [pistils] ), "Cali Hills," "choco," "lowland," "Santa Marta gold," and "purple" give us some idea of the color of older varieties and the location of cultivation.

In response to an incredible demand by America for Cannabis, and the fairly effective control of Mexican Cannabis importation and cultivation through tightening border security and the use of Paraquat, Colombian farmers have geared up their operations. Most of the marijuana smoked in America is imported from Colombia. This also means that the largest number of seeds available for domes tic cultivation also originate in Colombia. Cannabis agri-business has squeezed out all but a few small areas where labor-intensive cultivation of high quality drug Cannabis such as "Ia mona amarilla" can continue. The fine marijuana of Colombia was often seedless, but commercial grades are nearly always well seeded. As a rule today, the more remote highland areas are the centers of commercial agriculture and few of the small farmers remain. It is thought that some highland farmers must still grow fine Cannabis, and occasional connoisseur crops surface. The older seeds from the legendary Colombian strains are now highly prized by breeders. In the heyday of "Colombian gold" this fine cerebral marijuana was grown high in the mountains. Humid lowland marijuana was characterized by stringy, brown, fibrous floral clusters of sedative narcotic high. Now highland marijuana has become the commercial product and is characterized by leafy brown floral clusters and sedative effect. Many of the unfavorable characteristics of imported Colombian Cannabis result from hurried commercial agricultural techniques combined with poor curing and storage. Colombian seeds still contain genes favoring vigorous growth and high THC production. Colombian strains also contain high levels of CBD and CBN, which could account for sedative highs and result from poor curing and storage techniques. Domestic Colombian strains usually lack CBD and CBN. The commercial Cannabis market has brought about the eradication of some local strains by hybridizing with commercial strains.

Colombian strains appear as relatively highly branched conical plants with a long upright central stem, horizontal limbs and relatively short internodes. The leaves are characterized by highly serrated slender leaflets (7-11) in a nearly complete to overlapping circular array of varying shades of medium green. Colombian strains usually flower late in temperate regions of the northern hemisphere and may fail to mature flowers in colder climates. These strains favor the long equatorial growing seasons and often seem insensitive to the rapidly decreasing daylength during autumn in temperate latitudes. Because of the horizontal branching pattern of Colombian strains and their long growth cycle, pistillate plants tend to produce many flowering clusters along the entire length of the stem back to the central stalk. The small flowers tend to produce small, round, dark, mottled, and brown seeds. Imported and domestic Colombian Cannabis often tend to be more sedative in psychoactivity than other strains. This may be caused by the synergistic effect of THC with higher levels of CBD or CBN. Poor curing techniques on the part of Colombian farmers, such as sun drying in huge piles resembling com post heaps, may form CBN as a degradation product of THC. Colombian strains tend to make excellent hybrids with more rapidly maturing strains such as those from Central and North America.

b) Congo - (5 north to 5 south latitude)

Most seeds are collected from shipments of commercial grade seeded floral clusters appearing in Europe.

c) Hindu Kush Range - Cannabis indica (Afghanistan and Pakistan) - (30 to 37 north latitude)

This strain from the foothills (up to 3,200 meters [10,000 feetj) of the Hindu Kush range is grown in small rural gardens, as it has been for hundreds of years, and is used primarily for the production of hashish. In these areas hashish is usually made from the resins covering the pistil late calyxes and associated leaflets. These resins are re moved by shaking and crushing the flowering tops over a silk screen and collecting the dusty resins that fall off the plants. Adulteration and pressing usually follow in the production of commercial hashish. Strains from this area are often used as type examples for Cannabis indica. Early maturation and the belief by clandestine cultivators that this strain may be exempt from laws controlling Cannabis sativa and indeed may be legal, has resulted in its proliferation throughout domestic populations of "drug" Cannabis. Names such as "hash plant" and "skunk weed" typify its acrid aroma reminiscent of "primo" hashish from the high valleys near Mazar-i-Sharif, Chitral, and Kandahar in Afghanistan and Pakistan.

This strain is characterized by short, broad plants with thick, brittle woody stems and short internodes. The main stalk is usually only four to six feet tall, but the relatively unbranched primary limbs usually grow in an upright fashion until they are nearly as tall as the central stalk and form a sort of upside-down conical shape. These strains are of medium size, with dark green leaves having 5 to 9 very wide, coarsely serrated leaflets in a circular array. The lower leaf surface is often lighter in color than the upper surface. These leaves have so few broad coarse leaflets that they are often compared to a maple leaf. Floral clusters are dense and appear along the entire length of the primary limbs as very resinous leafy balls. Most plants produce flowering clusters with a low calyx-to-leaf ratio, but the inner leaves associated with the calyxes are usually liberally encrusted with resin. Early maturation and extreme resin production is characteristic of these strains. This may be the result of acclimatization to northern temperate latitudes and selection for hashish production. The acrid smell associated with strains from the Hindu Kush appears very early in the seedling stage of both staminate and pistillate individuals and continues throughout the life of the plant. Sweet aromas do often develop but this strain usually loses the sweet fragrance early, along with the clear, cerebral psychoactivity.

Short stature, early maturation, and high resin production make Hindu Kush strains very desirable for hybridizing and indeed they have met with great popularity. The gene pool of imported Hindu Kush strains seems to be dominant for these desirable characteristics and they seem readily passed on to the F1 hybrid generation. A fine hybrid may result from crossing a Hindu Kush variety with a late-maturing, tall, sweet strain from Thailand, India, or Nepal. This produces hybrid offspring of short stature, high resin content, early maturation, and sweet taste that will mature high quality flowers in northern climates. Many hybrid crosses of this type are made each year and are currently cultivated in many areas of North America. Hindu Kush seeds are usually large, round, and dark grey or black in coloring with some mottling.

d) India Centra1 Southern - Kerala, Mysore, and Madras regions (10 to 20 north latitude)

Ganja (or flowering Cannabis tops) has been grown in India for hundreds of years. These strains are usually grown in a seedless fashion and are cured, dried, and smoked as marijuana instead of being converted to hashish as in many Central Asian areas. This makes them of considerable interest to domestic Cannabis cultivators wishing to reap the benefits of years of selective breeding for fine ganja by Indian farmers. Many Europeans and Americans now live in these areas of India and ganja strains are finding their way into domestic American Cannabis crops.

Ganja strains are often tall and broad with a central stalk up to 12 feet tall and spreading highly-branched limbs. The leaves are medium green and made up of 7 to 11 leaf lets of moderate size and serration arranged in a circular array. The frond-like limbs of ganja strains result from extensive compound branching so that by the time floral clusters form they grow from tertiary or quaternary limbs. This promotes a high yield of floral clusters which in ganja strains tend to be small, slender, and curved. Seeds are usually small and dark. Many spicy aromas and tastes occur in Indian ganja strains and they are extremely resinous and psychoactive. Medicinal Cannabis of the late 1800s and early 1900s was usually Indian ganja.

e) Jamaica - (18 north latitude)

Jamaican strains were not uncommon in the late 1960s and early 1970s but they are much rarer today. Both green and brown varieties are grown in Jamaica. The top-of-the-line seedless smoke is known as the "lamb's bread" and is rarely seen outside Jamaica. Most purported Jamaican strains appear stringy and brown much like low land or commercial Colombian strains. Jamaica's close proximity to Colombia and its position along the routes of marijuana smuggling from Colombia to Florida make it likely that Colombian varieties now predominate in Jamaica even if these varieties were not responsible for the original Jamaican strains. Jamaican strains resemble Colombian strains in leaf shape, seed type and general morphology but they tend to be a little taller, thinner, and lighter green. Jamaican strains produce a psychoactive effect of a particularly clear and cerebral nature, unlike many Colombian strains. Some strains may also have come to Jamaica from the Caribbean coast of Mexico, and this may account for the introduction of cerebral green strains.

f) Kenya - Kisumu (5 north to 5 south latitude)

Strains from this area have thin leaves and vary in color from light to dark green. They are characterized by cerebral psychoactivity and sweet taste. Hermaphrodites are common.

g) Lebanon - (34 north latitude)

Lebanese strains are rare in domestic Cannabis crops but do appear from time to time. They are relatively short and slender with thick stems, poorly developed limbs, and wide, medium-green leaves with 5 to 11 slightly broad leaflets. They are often early-maturing and seem to be quite leafy, reflecting a low calyx-to-leaf ratio. The calyxes are relatively large and the seeds flattened, ovoid and dark brown in color. As with Hindu Kush strains, these plants are grown for the production of screened and pressed hashish, and the calyx-to-leaf ratio may be less important than the total resin production for hashish making. Lebanese strains resemble Hindu Kush varieties in many ways and it is likely that they are related.

h) Malawi, Africa - (10 to 15 south latitude)

Malawi is a small country in eastern central Africa bordering Lake Nyasa. Over the past few years Cannabis from Malawi has appeared wrapped in bark and rolled tightly, approximately four ounces at a time. The nearly seedless flowers are spicy in taste and powerfully psycho active. Enthusiastic American and European Cannabis cultivators immediately planted the new strain and it has be come incorporated into several domestic hybrid strains. They appear as a dark green, large plant of medium height and strong limb growth. The leaves are dark green with coarsely serrated, large, slender leaflets arranged in a narrow, drooping, hand-like array. The leaves usually lack serrations on the distal (tip portion) 20% of each leaflet. The mature floral clusters are sometimes airy, resulting from long internodes, and are made up of large calyxes and relatively few leaves. The large calyxes are very sweet and resinous, as well as extremely psychoactive. Seeds are large, shortened, flattened, and ovoid in shape with a dark grey or reddish brown, mottled perianth or seed coat. The caruncle or point of attachment at the base of the seed is uncommonly deep and usually is surrounded by a sharp edged lip. Some individuals turn a very light yellow green in the flowering clusters as they mature under exposed conditions. Although they mature relatively late, they do seem to have met with acceptance in Great Britain and North America as drug strains. Seeds of many strains appear in small batches of low-quality African marijuana easily available in Amsterdam and other European cities. Phenotypes vary considerably, however, many are similar in appearance to strains from Thailand.

i) Mexico - (15 to 27 north latitude)

Mexico had long been the major source of marijuana smoked in America until recent years. Efforts by the border patrols to stop the flow of Mexican marijuana into the United States were only minimally effective and many varieties of high quality Mexican drug Cannabis were continually available. Many of the hybrid strains grown domestic ally today originated in the mountains of Mexico. In recent years, however, the Mexican government (with monetary backing by the United States) began an intensive pro gram to eradicate Cannabis through the aerial spraying of herbicides such as Paraquat. Their program was effective, and high quality Mexican Cannabis is now rarely available. It is ironic that the NIMH (National Institute of Mental Health) is using domestic Mexican Cannabis strains grown in Mississippi as the pharmaceutical research product for chemotherapy and glaucoma patients. In the prime of Mexican marijuana cultivation from the early 1960s to the middle 1970s, strains or "brands" of Cannabis were usually affixed with the name of the state or area where they were grown. Hence names like "Chiapan," "Guerreran," "Nayarit," "Michoacan," "Oaxacan," and "Sinaloan" have geo graphic origins behind their common names and mean something to this very day. All of these areas are Pacific coastal states extending in order from Sinaloa in the north at 27; through Nayarit, Jalisco, Michoacan, Guerrero, and Oaxaca; to Chiapas in the south at 15 - All of these states stretch from the coast into the mountains where Cannabis is grown.

Strains from Michoacan, Guerrero, and Oaxaca were the most common and a few comments may be ventured about each and about Mexican strains in general.

Mexican strains are thought of as tall, upright plants of moderate to large size with light to dark green, large leaves. The leaves are made up of long, medium width, moderately serrated leaflets arranged in a circular array. The plants mature relatively early in comparison to strains from Colombia or Thailand and produce many long floral clusters with a high calyx-to-leaf ratio and highly cerebral psychoactivity. Michoacan strains tend to have very slender leaves and a very high calyx-to-leaf ratio as do Guerreran strains, but Oaxacan strains tend to be broader-leafed, often with leafier floral clusters. Oaxacan strains are generally the largest and grow vigorously, while Michoacan strains are smaller and more delicate. Guerreran strains are often short and develop long, upright lower limbs. Seeds from most Mexican strains are fairly large, ovoid, and slightly flattened with a light colored grey or brown, unmottled perianth. Smaller, darker, more mottled seeds have appeared in Mexican marijuana during recent years. This may indicate that hybridization is taking place in Mexico, possibly with introduced seed from the largest seed source in the world, Colombia. No commercial seeded Cannabis crops are free from hybridization and great variation may occur in the offspring. More recently, large amounts of hybrid domestic seed have been introduced into Mexico. It is not uncommon to find Thai and Afghani phenotypes in recent shipments of Cannabis from Mexico.

j) Morocco, Rif Mountains - (35 north latitude)

The Rif mountains are located in northernmost Morocco near the Mediterranean Sea and range up to 2,500 meters (8,000 feet). On a high plateau surrounding the city of Ketama grows most of the Cannabis used for kif floral clusters and hashish production. Seeds are broad-sown or scattered on rocky terraced fields in the spring, as soon as the last light snows melt, and the mature plants are harvested in late August and September. Mature plants are usually 1 to 2 meters (4 to 6 feet) tall and only slightly branched. This results from crowded cultivation techniques and lack of irrigation. Each pistillate plant bears only one main terminal flower cluster full of seeds. Few staminate plants, if any, are pulled to prevent pollination. Although Cannabis in Morocco was originally cultivated for floral clusters to be mixed with tobacco and smoked as kif, hashish production has begun in the past 30 years due to Western influence. In Morocco, hashish is manufactured by shaking the entire plant over a silk screen and collecting the powdery resins that pass through the screen. It is a matter of speculation whether the original Moroccan kif strains might be extinct. It is reported that some of these strains were grown for seedless flower production and areas of Morocco may still exist where this is the tradition.

Because of selection for hashish production, Moroccan strains resemble both Lebanese and Hindu Kush strains in their relatively broad leaves, short growth habit, and high resin production. Moroccan strains are possibly related to these other Cannabis indica types.

k) Nepal - (26 to 30 north latitude)

Most Cannabis in Nepal occurs in wild stands high in the Himalayan foothills (up to 3,200 meters [10,000 feet]). Little Cannabis is cultivated, and it is from select wild plants that most Nepalese hashish and marijuana originate. Nepalese plants are usually tall and thin with long, slightly branched limbs. The long, thin flowering tops are very aromatic and reminiscent of the finest fresh "temple ball" and "finger" hashish hand-rubbed from wild plants. Resin production is abundant and psychoactivity is high Few Nepalese strains have appeared in domestic Cannabis crops but they do seem to make strong hybrids with strains from domestic sources and Thailand.

I) Russian - (35 to 60 north latitude) Cannabis ruderalis (uncultivated)

Short stature (10 to 50 centimeters [3 to 18 inches]) and brief life cycle (8 to 10 weeks), wide, reduced leaves and specialized seeds characterize weed Cannabis of Russia. Janischewsky (1924) discovered weedy Cannabis and named it Cannabis ruderalis. Ruderalis could prove valuable in breeding rapidly maturing strains for commercial use in temperate latitudes. It flowers when approximately 7 weeks old without apparent dependence on daylength. Russian Cannabis ruderalis is nearly always high in CBD and low in THC.

m) South Africa - (22 to 35 south latitude)

Dagga of South Africa is highly acclaimed. Most seeds have been collected from marijuana shipments in Europe. Some are very early-maturing (September in northern latitudes) and sweet smelling. The stretched light green floral clusters and sweet aroma are comparable to Thai strains.

n) Southeast Asia - Cambodia, Laos, Thailand and Vietnam (10 to 20 north latitude)

Since American troops first returned from the war in Vietnam, the Cambodian, Laotian, Thai, and Vietnamese strains have been regarded as some of the very finest in the world. Currently most Southeast Asian Cannabis is produced in northern and eastern Thailand. Until recent times, Cannabis farming has been a cottage industry of the northern mountain areas and each family grew a small garden. The pride of a farmer in his crop was reflected in the high quality and seedless nature of each carefully wrapped Thai stick. Due largely to the craving of Americans for exotic marijuana, Cannabis cultivation has become a big business in Thailand and many farmers are growing large fields of lower quality Cannabis in the eastern lowlands. It is suspected that other Cannabis strains, brought to Thailand to replenish local strains and begin large plantations, may have hybridized with original Thai strains and altered the resultant genetics. Also, wild stands of Cannabis may now be cut and dried for export.

Strains from Thailand are characterized by tall meandering growth of the main stalk and limbs and fairly extensive branching. The leaves are often very large with 9 to 11 long, slender, coarsely serrated leaflets arranged in a drooping hand like array. The Thai refer to them as "alligator tails" and the name is certainly appropriate.

Most Thai strains are very late-maturing and subject to hermaphrodism. It is not understood whether strains from Thailand turn hermaphrodite as a reaction to the extremes of northern temperate weather or if they have a genetically controlled tendency towards hermaphrodism. To the dismay of many cultivators and researchers, Thai strains mature late, flower slowly, and ripen unevenly. Retarded floral development and apparent disregard for changes in photoperiod and weather may have given rise to the story that Cannabis plants in Thailand live and bear flowers for years. Despite these shortcomings, Thai strains are very psychoactive and many hybrid crosses have been made with rapidly maturing strains, such as Mexican and Hindu Kush, in a successful attempt to create early-maturing hybrids of high psychoactivity and characteristic Thai sweet, citrus taste. The calyxes of Thai strains are very large, as are the seeds and other anatomical features, leading to the misconception that strains may be polyploid. No natural polyploidy has been discovered in any strains of Cannabis though no one has ever taken the time to look thoroughly. The seeds are very large, ovoid, slightly flattened, and light brown or tan in color. The perianth is never mottled or striped except at the base. Greenhouses prove to be the best way to mature stubborn Thai strains in temperate climes.

3. Hybrid Drug Phenotypes

a) Creeper Phenotype - This phenotype has appeared in several domestic Cannabis crops and it is a frequent phenotype in certain hybrid strains. It has not yet been deter mined whether this trait is genetically controlled (dominant or recessive), but efforts to develop a true-breeding strain of creepers are meeting with partial success. This phenotype appears when the main stalk of the seedling has grown to about 1 meter (3 feet) in height. It then begins to bend at approximately the middle of the stalk, up to 700 from the vertical, usually in the direction of the sun. Sub sequently, the first limbs sag until they touch the ground and begin to grow back up. In extremely loose mulch and humid conditions the limbs will occasionally root along the bottom surface. Possibly as a result of increased light exposure, the primary limbs continue to branch once or twice, creating wide frond-like limbs of buds resembling South Indian strains. This phenotype usually produces very high flower yields. The leaves of these creeper phenotype plants are nearly always of medium size with 7-11 long, narrow, highly serrated leaflets.

b) Huge Upright Phenotype - This phenotype is characterized by medium size leaves with narrow, highly serrated leaflets much like the creeper strains, and may also be an acclimatized North American phenotype. In this phenotype, however, a long, straight central stalk from 2 to 4 meters (6.5 to 13 feet) tall forms and the long, slender primary limbs grow in an upright fashion until they are nearly as tall or occasionally taller than the central stalk. This strain resembles the Hindu Kush strains in general shape, except that the entire domestic plant is much larger than the Hindu Kush with long, slender, more highly branched primary limbs, much narrower leaflets, and a higher calyx-to-leaf ratio. These huge upright strains are also hybrids of many different imported strains and no specific origin may be determined.

The preceding has been a listing of gross phenotypes for several of the many strains of Cannabis occurring world wide. Although many of them are rare, the seeds appear occasionally due to the extreme mobility of American and European Cannabis enthusiasts. As a consequence of this extreme mobility, it is feared that many of the world's finest strains of Cannabis have been or may be lost forever due to hybridization with foreign Cannabis populations and the socio-economic displacement of Cannabis cultures worldwide. Collectors and breeders are needed to preserve these rare and endangered gene pools before it is too late.

Various combinations of these traits are possible and inevitable. The traits that we most often see are most likely dominant and the improvement of Cannabis strains through breeding is most easily accomplished by concentrating on the dominant phenotypes for the most important traits. The best breeders set high goals of limited scope and ad here to their ideals.