32
Genetic future of hemp
David P. Watson and Robert C. Clarke
International Hemp Association
Postbus 75007, 1070 AA Amsterdam, The Netherlands
What will be the traits required for future industrial hemp varieties? Many industrial hemp cultivators will desire increased cellulose content for biomass fuel production, higher primary fiber yields for pulping, or high yields of extra fine fibers for textiles. Seed growers and processors will require high-yielding varieties with increased levels of fatty acids or other target compounds. Included in this list would also be common agronomic traits such as tolerance to drought, wet heavy soils, salt, cold, heat or humidity and resistance to pests and diseases. The general agronomic suitability of hemp varieties for specialized altitudes or latitudes beyond the limited present-day European range of industrial hemp growing is also a particularly important future consideration.
Table 1. Registered industrial hemp varieties (47 total) and their commercial availability (21 total).
France - 10 Available: 'Fedora 19' 'Felina 34' 'Fedrina 74' 'Futura 77' Unavailable: 'Fibrimon 21' 'Fibrimon 24' 'Fibrimon 56' 'Férimon 12' 'Epsilon 68' 'Santhica 23' Hungary - 5 Available: 'Kompolti' 'Kompolti Sárgasázrú' 'Uniko-B' 'Kompolti Hibrid TC' 'Fibriko' Poland - 3 Available: 'Bialobrzeskie' 'Beniko' Unavailable: 'Dolnoslaskie' |
Romania - 4 Available: 'Fibramulta 151' 'Lovrin 110' 'Sequeni' 'Irene' Bulgaria - 2 Unavailable: 'Mecnaja copt.' 'Silistrensi' Ukraine - 11 Available: 'YUSO 13' 'YUSO 31' 'Glukhov 33' 'Zenica' Unavaillable: 'Dneprovskaya Odnodomnaya 6' 'Kuban' 'YUSO 11' 'YUSO 14' 'YUSO 15' 'YUSO 16' |
Italy - 5 Unavailable: 'Carmagnola' 'Carmagnola Selezionata' or 'CS' 'Fibranova' 'Eletta Campana' 'Suprafibra' Slovenia - 2 Unavailable: 'Rudnik' 'Pesnica' Spain - 2 Unavailable: 'Delta 405' 'Delta-Llosa' Czechoslovakia - 1 Unavailable: 'Rastslaviska' Yugoslavia - 1 Available: 'Novosadska Konoplja' Germany - 1 Available: 'Fasamo' |
No developed hemp varieties exist that are
suitable for equatorial or even subtropical latitudes. Of the 47 hemp varieties
registered or in commercial trade (Table 1), European varieties account for all of them.
All were developed in (and for) regions north of the 45th parallel and in general
will not perform well if moved closer to the equator by even as little as 10-15 degrees,
as demonstrated by recent field trials in South Africa (Dippenaar et al.
1996). The limited production of hemp crops in subtropical Asia relies solely on
unimproved landraces of variable cannabinoid content. The International Hemp
Association (IHA) often receives requests for low-THC, EU-registered industrial hemp
varieties that would be suitable for Brazil, Cambodia, Jamaica, Hawaii, Nigeria, Viet Nam,
The Congo (formerly Zaire) and other tropical and sub-tropical regions. We are
forced to respond that none of the available registered varieties will perform well in
those regions. Northern temperate varieties are adapted to long summer daylength
and flower in Europe in the Autumn, when the days become shorter. In equatorial
regions, the daylength is never long enough to prevent flowering and these northern
varieties only reach a meter or two in height before they flower. European varieties
growing in foreign environments are also attacked by a wide range of pests and diseases
for which they have no resistance. We suggest that there is an immediate need for a
tropical hemp collection and equatorial facilities to be established for tropical
industrial hemp variety development. Currently, only unimproved landraces (with
fiber content below 20% and THC levels that may reach 3%) satisfy the daylength
restrictions of tropical areas.
Canadian and northern European farmers have the
opposite problem with the available selection of European cultivars. Few European
varieties will mature early enough to allow seed production and variety multiplication in
the climatic and daylength conditions of Canada and northern Europe. In 1925, R. J.
Hutchinson, the Canadian Chief Officer of the Division of Economic Fiber Production
observed:
A considerable handicap to the growing of hemp in Canada is the difficulty of obtaining good seed at a reasonable price. While our climate is favorable for producing hemp for fiber, the growing season, in most districts, is not long enough to fully mature the seed. Subsequently, hemp seed production trials were undertaken near Ottawa and other stations in areas with longer growing seasons: Summerland, B.C.; Sidney, B.C.; Sanichton, B.C.; Harrow, Ontario; and Kentville, Nova Scotia. These experiments demonstrated that the only areas in Canada with a growing season suitable to reliably mature seed of such a high fiber yielding variety as Minnesota No. 8 [extinct American cultivar] was the southern tip of the Niagara Peninsula near Harrow.
This situation has not changed for Canada in the last 70 years.
Confusion in the publics mind between
rope and dope continues to plague the industrial hemp industry in many parts
of the world. Producers of recently registered monoecious varieties with trace or
claimed null levels of THC, such as the newest Ukrainian YUSO-15 or the French
Epsilon 68 and Santhica 23 can only hope to solve the THC
problem for a limited portion of hemps potential range. While it is
easier to reduce the THC content of monoecious varieties through in-breeding, growing
these types may suffer serious drawbacks, e.g., decreased vigor due to inbreeding
depression resulting in lowered fiber and seed yield. The present European Union
(EU) THC limit of 0.3% is certainly low enough to prevent any diversion of industrial hemp
to drug purposes and no further reductions are necessary. However, as a strategic
economic and political maneuver, the French may use their newest varieties to push for
unneeded EU legislation that would forbid the cultivation of any industrial hemp variety
containing more than 0.1% THC, mimicking regulations in the former Soviet Union.
This legislation would, in effect, outlaw all registered varieties except those of the
French and a few Ukrainian varieties.
The EU recently adopted a resolution that
subsidies will be paid only to hemp growers who do not harvest their hemp until its seeds
have ripened (see pg. 38). If the stand is harvested
before the seeds are ripe, the farmer will not only be refused the subsidy, but may also
be liable for a 50,000 DM fine (Bócsa 1996)! This resolution is especially damaging
to the southern Italian varieties, and may prevent the registration of high yielding
dioecious varieties such as Kompolti Hibrid TC and Novosadska
Konoplja because they take longer to mature than the French varieties.
However, any farmer north of France trying to allow the crop to mature its seed in the
often cold, wet and foggy Autumn harvest weather will encounter difficulties in most
years. The fact that harvesting hemp crops to seed maturity compromises fiber
quality also seems to have escaped the EU regulators.
To date, there is only one hemp variety
(Uniko-B) specifically designed for high-yield seed production. One to 1.5 t/ha is
presently the maximum possible seed yield using this high yielding Hungarian unisexual
variety. Seed yields from the dioecious variety Novosadska Konoplja in
Yugoslavia also approach these levels. Additional high-yielding seed varieties must
be developed if hemp seed is to compete in price with other grains. With a seed
variety developed for high yield and mechanized harvesting, the yields might be greatly
increased. Drug varieties developed for high flower yield have produced more than a
kilogram of seed per plant. Cultivars also will be developed for the food industry
with specific desirable protein and oil profiles. The nutritional value and
implications of hemp seed have recently been reviewed by Deferne and Pate (1996).
Interest in hemp food varieties is increasing,
as shown by Theimer and Mölleken (1997) in their world survey of seed fatty acid and
protein profiles (see pg. 13). They are examining the entire Vavilov Research
Institute (VIR) collection of more than 400 Cannabis accessions, the 45 currently
registered hemp varieties and about 100 landraces from around the world.
Canadas $60,000 research grant to Ruth Shamai, President of The Natural Order, will
kick-start a North American research into hemp seed and oil production. The
pioneering work of Callaway and Laakkonen (1996) in Finland may accelerate this
process. Callaway et al. (1996) announced a new fatty acid discovery that
reveals the nutritional superiority of, and possible nutriceutical
applications for, high-latitude hemp seed suitable for cultivation across Canada and the
Nordic countries. This break-through would not have been possible without VIR 313
and VIR 315, the initial breeding materials that originated from the VIR Cannabis
germplasm collection. Other genetically determined seed traits to be explored may
include special amino acid profiles, better balanced essential fatty acid (EFA) contents
for food use, or unusual oil components for industrial uses.
Hemp varieties with extremely small seeds for
baking, very large seeds for easier hulling and thin and soft-shelled variants for snack
foods, are possible to develop for whole seed use. The variability of hemp seed size
is striking. Industrial hemp varieties normally produce seeds of 40-60 seeds per
gram, but wild Cannabis growing at 3000 meters in Kashmir produces tiny seeds of
more than 1000 to the gram. Extremely large seeds of 15-25 to the gram from
Afghanistan, Chile, China, Japan, Korea and Pakistan have been reported. One of the
largest expenses in hemp fiber growing is seed cost. If hemp seeds were half their
current weight, then farmers could buy and sow half as many kilograms of seed to achieve
the same crop density.
Varieties could be developed with gross
morphological markers to help agricultural inspectors identify approved industrial
varieties. Suggestions have included red, yellow or purple plants, those having
leaves with different shapes or with even numbers of leaflets, and varieties with THC
genes that could be turned off or disabled permanently. Hemp with yellow stems has
been developed for paper (e.g., Kompolti Sárgaszárú) thereby
producing a better color paper using less bleach during pulping. It has been
suggested that the use of Kompolti Sárgaszárú as a five percent admixture
to approved commercial hemp seed would facilitate field recognition of industrial hemp
crops by simply observing the color of the stalks (Bócsa 1994).
Late-maturing bulky hemp varieties with little
fiber, but high total cellulose yield might better suit biomass projects. Dr. James
Burke has grown hemp in Carlow, Ireland for four years to determine the effectiveness of
burning hemp for electrical energy production, rather than to continue to rely solely on
rapidly dwindling peat reserves. In addition, he has announced a contest for the
best power plant design to use this new fuel. The power plant will run on hemp,
paper wastes, and chicken manure and may be operational as soon as 1999, supplying power
to 30,000 homes, a significant percentage of Irish electrical needs. A cultivar
should be developed to suit the needs of such biomass energy producers.
Pharmaceutical varieties that are rich in
cannabinoids are currently being developed that can potentially relieve suffering for
millions worldwide. Natural THC can be grown and extracted at a fraction of the cost
of the synthetic equivalent and will successfully compete in the legitimate cannabinoid
pharmaceutical market, currently valued at over US$ 20 million. A host of other
naturally occurring cannabinoids (e.g. CBD) could also be approved for a wide
range of indications and varieties would be developed to supply any of these cannabinoids
in high concentrations.
Modifying or increasing the secondary
metabolites produced by Cannabis may help promote its resistance against attack
by pests. Unfortunately, we have even heard of considerations for incorporating
herbicide or pesticide resistance into industrial hemp varieties, similar to that found in
soybean varieties genetically engineered to be resistant to the broadleaf herbicide,
Roundup®. We believe that this would be tragic. We must be careful not to
create the next agro-nightmare, as is cotton, the largest user of farm chemicals of any
crop. Hemp already offers us an environmentally compatible fiber, seed and
medicinal crop that is free of a dependence upon agricultural chemicals. There is
nothing wrong with hemp and there is no need to fix it.
Breeders need only develop cultivars for specific uses and regions of cultivation.
Questions arise as to who will develop these
desired new varieties and where will they obtain the initial genetic raw materials
required to develop them? The 46 currently registered varieties were developed
primarily by starting with a few promising local landraces selected over hundreds of years
by peasant farmers in areas of traditional hemp cultivation. The modern
industrial hemp varieties are descendant from very few ancestors. The European
varieties are based on only three gene pools: Northern and Central European ecotypes,
Southern European ecotypes and East Asian ecotypes (de Meijer 1995). The 33
registered hemp varieties for which pedigree information is available consist of 23
monoecious, 14 dioecious and one unisex types. All originated entirely, or in part,
from landraces of the Central and Southern European ecotypes and only two of the Hungarian
varieties incorporate ancestors from the Far Eastern ecotype. All of the monoecious
and unisex varieties derived their monoecious trait from Fibrimon. Seven
of the nine dioecious varieties include genes from Hungarian landraces and varieties that
were all originally derived from Italian landraces. A single accession from China
was used to establish the hybrid triple cross varieties from Hungary.
Italian landraces, combined with the single monoecious line Fibrimon and a
single Chinese landrace (along with a few other Central and Southern European accessions)
were used to breed all current industrial hemp varieties (Table 2). This is an
extremely narrow gene pool for an entire crop plant and explains why industrial hemp
varieties are so poorly suited to growing in regions outside Europe.
Table 2. Country of origin, ancestors, geographical origins and ecotype/gene pool classification of the currently available registered hemp varieties (de Maijer 1995).
Country/ Sexual type |
Ancestors | Geographical Origins |
Ecotype/ Gene pool |
||
France 10 monoecious |
'Fibrimon' with exotic |
Russia Italy/Turkey Russia, Hungary and Italy |
Central European Southern European Central European Southern European |
||
Hungary 4 dioecious 1 unisex |
Fleischmann 'Kompolti' 'Fibrimon' Kinai |
Hungary/Italy Hungary/Italy Russia Italy/Turkey China |
Southern European Southern European Central European Southern European Far Eastern |
||
Poland 3 monoecious |
'Kompolti' 'Fibrimon' 'LKCSD' |
Italy Russia Italy/Turkey Russia Russia |
Southern European Central European Southern European Central European Central European |
||
Romania 2 dioecious 2 monoecious |
'ICAR 42-118' Silistra landrace 'Fibrimon' |
Italy/Turkey Bulgaria Russia Italy/Turkey |
Southern European Southern European Central European Southern European |
||
Ukraine 2 dioecious 7 monoecious |
'Szegedi' 'Fibrimon' |
Hungary Russia Italy/Turkey |
Southern European Central European Southern European |
||
Yugoslavia 1 dioecious |
Fleischmann | Hungary/Italy | Southern European | ||
Germany 1 monoecious |
'Bernburg' and 'Schurigs' |
Russia | Central European | ||
Italy | 'Carmagnola' 'Bredemann Elite' |
Italy Russia |
Southern European Central European |
Cannabis most likely originated in
Central Asia and soon spread to Europe, India and China, following ancient trade routes,
and eventually reached Africa and the New World. Local landraces evolved in all of
these introduced climates and new cultural settings. Until the 1970s, many
indigenous cultures still used hemp and continued to grow their own local landraces each
year. Today, few traditional cultures still grow and process hemp. Almost all
have stopped using hemp and now prefer to buy market cloth or spin and weave flax, cotton,
wool or synthetics. Increased availability, lower cost, ease of use, and better
performance for some applications like wool (for warmth) and synthetics (for maritime
uses) have pushed hemp into relative obscurity in a short time. When a local
landrace is not reproduced every five to ten years, the seeds will most likely die and
that germplasm may be gone forever. Seeds must be properly stored in a gene bank and
reproduced periodically under ideal conditions. The vast majority of landraces may
already be extinct simply because of neglect resulting from modern market pressures.
Another obstacle for breeders intending to work
with industrial hemp is the confused legal status of the genus Cannabis. In
many countries, even in traditional hemp cultivation areas, all Cannabis is
illegal to grow, regardless of its intended end use. In some regions, even hemp seed
is illegal. Plants with little THC content are often destroyed even when found
growing wild, because they look like marijuana. The last 60-70 years have been
disastrous for the Cannabis gene pool, and many local landraces, the result of
hundreds of years of selection for local use, have been lost because of Cannabis
eradication, neglect on the part of agricultural officials and industry, anti-Cannabis
propaganda and the general trend (until recently) to reduce industrial hemp breeding and
research. Genetic materials are a living heri-tage and we are their custodians.
We must concentrate our efforts to collect, preserve, characterize and utilize the
remaining Cannabis genetic resources before it is too late.
As the worldwide reduction in diversity of
local hemp landraces used by indigenous farmers continues, the importance of gene banks
becomes obvious. Unfortunately, few comprehensive Cannabis germplasm
collections exist. Most of them are held by national gene banks that may or may not
share their valuable inventories with other breeders. The largest collection of hemp
germplasm is maintained by the Vavilov Institute of Plant Research (VIR) in St.
Petersburg, Russia, and, with a cooperative development agreement, they will share small
amounts of varieties for which they have sufficient seed.
In 1992, in order to preserve the VIRs
collection for future breeders, the International Hemp Association (IHA) negotiated a
humanitarian aid project, the VIR/IHA Cannabis Germplasm Preservation Project, to
ensure the timely reproduction and survival of the entire VIR Cannabis seed
collection. The project work began in 1993. From 1993 to 1996, the IHA has
donated US$ 50,000 for project funding. Unfortunately, because of the disjunctions
associated with the changeover from a centralized command economy to a capitalist market
system, science in general and the VIR in particular, have suffered tremendously.
Three quarters of the VIR staff of 2000 have been laid off, salaries are up to 6
months late, and there is no funding to reproduce the 400,000 seed accessions of other
economic plants and their wild relatives held by the largest and oldest gene bank in the
world!
In 1993, the IHA/VIR project developed two key
criteria be fulfilled before a Cannabis accession was considered adequately
reproduced. The primary goal of the germplasm preservation project is the
conservation of the entire gene pool of each accession. It is very important that
the population size is large enough to ensure that as many of the genes as possible within
the accessions gene pool are reproduced in the resultant seed. A minimum limit
of 1,000 plants was set for monoecious varieties, and 2,000 plants for dioecious ones.
This assures that 99% of the gene pool will be reproduced with each reproduction
(Crossa et al. 1993). Unfortunately the seed reserves of many of the
accessions consisted of less than 1,000 viable seeds, making our goal impossible to
achieve. The secondary goal is to reproduce the accessions in sufficient quantities
to maintain a reserve for future reproductions and to distribute seed to researchers
worldwide. A minimum limit of 300 grams of seed was set for long term storage and
later reproductions. Seeds can be released to the research community only if more
than this amount is held by the VIR. Three hundred grams is approximately 15,000
seeds and will allow the following three storage regimes:
1.) 5,000 seeds stored at an ambient temperature of 15 degrees Celsius and moisture content of about 10%, in an active collection for reproduction,
2.) 5,000 seeds kept at 4-6 degrees Celsius and 7% moisture content in refrigerated medium-term storage, and
3.) 5,000 seeds archived in a reserve collection at -20 degrees Celsius and 6% moisture in frozen long-term storage.
About 40 percent of the seed accessions are now stored in refrigerated or frozen
storage.
The IHA, with the generous support of our
members, has nearly saved the VIRs Cannabis germplasm collection from
extinction, but to use this resource to its full potential, the entire collection must be
grown out in common gardens at appropriate latitudes and evaluated for uniqueness, variety
purity and the relative value of its agronomic traits. The VIR made a limited
evaluation of the collection in 1975 and the results were published by the VIR in Russian,
but this effort should be repeated and expanded from a modern breeders perspective.
Breeders worldwide could then more easily understand and utilize this valuable
resource.
Because of the technical and financial
difficulties in reproducing the VIR Cannabis collection, there has likely been
considerable loss of genetic diversity and purity through low population sizes and
incomplete isolation. In addition, many of their accessions may be so similar to
each other that they need no longer be represented and reproduced as separate accessions,
which only results in pointless extra maintenance, storage and reproduction costs.
VIR materials are also present in limited amounts in other gene banks and research
institutes, where they are adequately maintained and stored.
A common goal of hemp breeders should be to
establish a smaller and broader core collection of Cannabis germplasm that has
been exhaustively characterized agronomically, in the field and at the molecular and
chemical levels in the laboratory. Only then can we see what diversity really is
available for future research. This core collection could then be maintained with
optimal reproduction and storage methodology. The individual accession evaluations
should also be presented in a concise form making it accessible to a wide range of plant
breeders.
Unfortunately, the 1997 VIR/IHA Cannabis
Germplasm Preservation Project is currently slowed due to insufficient funding.
While most of the collection is not presently at risk, the planned grow-out and
evaluation of the entire collection will not happen this year. Anyone who can help
locate sources of funding for next years VIR project is invited to contact the IHA.
References