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vol 6 no 2 table of contents vol 6 no 2 table of contents vol 6 no 2 next article

Agronomic characteristics of some hemp genotypes

Vito Mediavilla, Paolo Bassetti and Marianne Leupin

Swiss Federal Research Station for Agroecology and Agriculture (FAL),
Reckenholzstrasse 191, CH-8046 Zurich, Switzerland; e-mail: <vito.mediavilla@fal.admin.ch>

Eric Mosimann

Swiss Federal Research Station for Plant Production (RAC),
Changins, CH-1260 Nyon 1, Switzerland


Mediavilla, Vito, Paolo Bassetti, Marianne Leupin and Eric Mosimann 1999. Agronomic characteristics of some hemp genotypes. Journal of the International Hemp Association 6(2): 45, 48-53. In various field experiments carried out in Switzerland between 1993 and 1998, important agronomic characteristics of 29 hemp varieties were studied. These experiences allowed us to classify the maturation rates of each variety and the ratio of male to female plants in the population. The result of THC analyses confirmed those found in laboratories of other countries and the relevance of Swiss legislation. These varieties were tested with the aim of their utilisation for fibre, seed oil and essential oil.



Figure 1. Hemp cultivars growing in Switzerland.

Introduction

It is assumed that the origin of hemp (Cannabis sativa L.) is central Asia. From there it spread to the East and to the West, where it was used by the Chinese, Greeks and Romans. In Europe, it was cultivated widely until the First World War as a fibre crop (Bòcsa and Karus 1997). Afterwards, the cultivation of hemp in most Central European countries almost disappeared, as it did in North America. Hemp fibre was not competitive compared with synthetic fibres. In addition, prohibitions made its cultivation difficult. Interest in this crop awoke about ten years ago for various reasons. Today, in numerous European and Asiatic countries, hemp is cultivated as a fibrous raw material. On the African continent, it is used predominantly for its medical and psychoactive properties. In Switzerland, the cultivation of hemp for drug production is forbidden. On the other hand, the use of hemp as raw materials (fibres, food or body-care) is permitted and even promoted.

Because all strains within the genus Cannabis intercross readily, it is today generally thought that Cannabis consists of only one species C. sativa L. Depending upon agronomic characteristics and cannabinoid content, hemp populations are divided into truly wild and naturalised populations, fibre land races, fibre cultivars, ornamental and drug strains. It is additionally assumed that most rural populations (so-called C. ruderalis, C. sativa ssp. ruderalis and C. sativa var. spontanea) descend from previously cultivated fibre crops. The fibre varieties available today descend from strains, last developed in the mid-20th Century in Germany, France, Italy, Hungary and the former Soviet Union. This material was selected particularly with the aim of a high fibre yield and non-psychoactivity (De Meijer 1995).

Historical reports show that in Switzerland in 1943, Hungarian, German and Italian cultivars ("Bolognese Hemp") were cultivated. There were apparently no Swiss varieties at that time (Anonymous 1943). In the 1990's, as hemp cultivation was reintroduced within Switzerland, cultivation of the "Genuine Swiss Farmer Hemp" or "Natural Hemp" was publicised (Bonin 1994, Rabara 1999). Such seed was sold at excessive prices, had a very low germinability and were a variety mixture, the so-called "Swissmix". Its Swiss origin is very doubtful, as there was no Swiss cultivation between 1950 and 1990, (1), and no Swiss germaplasm was ever recorded in a gene bank.

 

Table 1. Trial description 1993-1998.


Year


Location


Seed density
kg/ha


N-fertilisation
kg/ha

1993

Zurich-Reckenholz, alt. 440 m above sea level

*

*

1993

Cadenazzo, TI, alt. 207 m above sea level

*

*

1994

Zurich-Reckenholz, alt. 440 m above sea level

60

115

1994

Cadenazzo, TI, alt. 207 m above sea level

60

120

1995

Zurich-Reckenholz, alt. 440 m above sea level

60

90

1995

Cadenazzo, TI, alt. 207 m above sea level

60

?120

1995

Changins VD, ... 430 m ü.M. alt. 440 m above sea level

60

90

1996

Zurich-Reckenholz, alt. 440 m above sea level

60

120

1997

Tenniken BL, alt. 604 m above sea level

40

120

1998

Moehlin AG, alt. 330 m above sea level

40

120

* Preliminary test without yield investigations


Materials and Methods

From 1993 to 1998, field tests at several locations in the North, the West and the South of Switzerland were carried out using various fibre hemp genotypes originating both from Europe and from new Swiss breeding activities. Test plots were sown in randomised blocks with three to four replications (Table 1). Sowing took place, using a cereal sowing machine, at the end of April with a seed density of between 40 and 60 kg/ha with. Soil nitrogen supplementation varied between 90 and 120 kg/ha. No weed control took place. Due to seed availability, not all varieties could be examined at all locations in every year. For this reason, the results are not fully statistically valid.

 

Table 2. Characteristics of the tested genotypes

Genotype
 


 

Alp King

Beniko

Bialobrzeskie

Fasamo

Fedora 19

Fedrina 74

Felina 34

Ferimon 12

Fibramulta

Futura 77

FxT

Helvetica 01

Helvetica 02

Helvetica 03

Helvetica Tell

Irene

Kompolti

Kompolti Hybrid TC

Livoniae

Lovrin 110

Moldovan

Novosadska

Novosadska plus

Secuieni 1

Swissmix

Uniko-B

USO 14

USO 31

Walliser Queen

Characteristics
 

Male
plants

Maturity rate*

Origin

 
 

 
 

Suitability

 
 

%
 

 
 

 
 

Switzerland CH

European
Union EU

 

Dioecious strain

50

Middle

CH

 

 

 

Monoecious cultivar

1

Early

PL

1999

 

Grains, GLA, fibres

Monoecious cultivar

1

Middle early

PL

 

 

Essential oil, fibres, (GLA)

Monoecious cultivar

1

Very early

D

1998

 

Grains, GLA

Monoecious cultivar**

1

Early

F

1994

 

Grains, (GLA, stem)

Monoecious cultivar**

1

Middle

F

1999

 

Stem

Monoecious cultivar**

1

Early

F

1994

 

Grains, essential oil, GLA

Monoecious cultivar

1

Early

F

1999

 

Grains

Dioecious cultivar

50

Middle

RM

 

 

Essential oil

Monoecious cultivar

1

Middle

F

1994

 

Stem, essential oil

Monoecious strain

10

Middle early

H

1997

 

Stem, grains

Dioecious strain

50

Middle early

CH

 

 

 

Dioecious strain

50

Middle early

CH

 

 

 

Dioecious strain

50

Middle

CH

1998

 

unknown

Dioecious strain

50

Middle early

CH

 

 

 

Monoecious cultivar

1

Middle early

RM

 

 

 

Dioecious cultivar

50

Late

H

1994

 

Stem, fibres, essential oil

Dioecious cultivar

50

Late

H

 

 

(essential oil)

Dioecious land race

50

Middle

Latvia

 

 

Grains

Dioecious cultivar

50

Middle

RM

1999

 

Essential oil

Dioecious land race

50

Middle

RM

 

 

Essential oil, (fibres)

Dioecious strain

50

Late

YU

 

 

(fibres)

Dioecious strain

50

Late

YU

 

 

 

Monoecious cultivar

5

Middle early

RM

 

 

(essential oil)

Dioecious strain mixture

50

Early

CH

 

 

 

Dioecious cultivar

30

Middle

H

1996

 

stem

Monoecious cultivar

1

Very early

Ukraine

 

 

Grains, GLA

Monoecious cultivar

1

Very early

Ukraine

1999

 

Grains, (GLA)

Dioecious strain

50

Very early

CH

 

 

 

*    Approximate time of the flowering in Central Switzerland: very early 4th week of July; early 1st week of August; middle early 2nd
      week of August; middle 3rd week of August; late 4th week of August.
**  Hybrid populations with about 50% female and 50% monoecious plants (Bòcsa personal communication 1999).


Results

Phenological characteristics

Hemp populations are composed of male, female and monoecious plants (Table 2). Varieties with male and female individuals are called dioecious (e.g., Kompolti or Lovrin 110). Monoecious varieties were selected from dioecious populations (e.g., French cultivars). They are reputed to have a more uniform fibre quality and higher grain and flower yields.

Hemp varieties differ also in their maturation rates. In Central Switzerland, the time of flowering (Mediavilla et al. 1998) was for the very early maturing cultivars like 'Fasamo' and 'USO 14' in the fourth week of July. For the late cultivars like 'Kompolti' and 'Novosadska', flowering took place in the fourth week of August (Table 2). The maturation rate greatly influenced plant height and, therefore, the stem yield (Fig. 2b).


Figure 2. THC content (a), plant height (b), stem yield (c) and seed yield (d) of different hemp genotypes. Trials 1993-1998

THC and other cannabinoids

Cannabinoids are a group of secondary compounds (terpenolic phenols), which are found only in Cannabis. They are localised mainly in the perigonal bracts of female inflorescences. Only Δ9-tetrahydrocannabinol (THC) seems to have significant psychoactive activity. The THC content in the inflorescences of our specimens was analysed according to the method valid in the European Union (Anonymous 1998, modified according De Meijer et al. 1992, as well as Mediavilla and Brenneisen 1996) and was expressed in percent drug present relative to the dry matter. Investigations in Switzerland showed that the THC content is mainly determined genetically and that the cultivation altitude does not have significant influence (Mediavilla and Brenneisen 1996).

Results of the THC analyses are similar to those available references (e.g., De Meijer et al. 1992). In Swissmix and in several other genotypes, the THC content was clearly higher than the threshold value of the 0.3% valid in the European Union and in Switzerland for industrial hemp (Fig. 2a). On the basis of these results, new low THC varieties were registered in the Swiss variety catalogue, as contributions to hemp cultivation.

Numerous references state that resistance against insects, fungi, bacteria and nematodes and also fibre quality and the crop husbandry depend on the THC content of a hemp population (e.g., Pate 1994, Rabara 1999). This hypothesis has yet to be confirmed (De Meijer 1993, McPartland 1997). We have found that drug strains - which are not adapted to Swiss conditions - are more susceptible to several diseases. It is well-known that Swissmix is very susceptible to Botrytis cinerea when cultivated outdoors. Our past experience showed that plant THC content does not have agronomic importance. McPartland (1997) assumes that disease resistance or robustness of hemp is based on a multiplicity of other compounds, and that the cannabinoids play only a minor role.

 

Table 3. Important characteristics of different genotypes for the fibre production. Bark content: average 1995-1998 (4 trials); diameter: average 1996-1998 (3 trials); fibre content, chemical composition and decortication facility: 1997 (1 trial).

Genotype
 

Bark
content

Fibre
content

Chemical composition
% bark

Diameter
 

Decortication facility
index*


 

 


 

 

 
 

% stem
 

% bark
 

Uronic acid
content**

Pentose
content**

Lignin
content

stem
mm

 
 

Beniko

46.1

66.0

5.47

4.65

1.44

6.30

0.73

Bialobrzeskie

41.9

65.2

5.57

5.06

1.61

6.55

0.73

Fasamo

32.7

59.0

6.78

6.04

1.93

4.90

0.61

Fedora 19

33.6

62.8

6.27

5.24

1.52

6.54

0.76

Felina 34

36.2

65.6

4.62

3.94

1.73

6.62

0.76

Futura 77

35.2

65.1

5.54

5.24

1.84

6.73

0.56

FxT

33.2

66.1

5.33

4.78

1.82

6.49

0.80

Irene

37.9

66.8

5.26

5.25

 

6.85

 

Kompolti

43.8

59.8

5.15

5.03

1.52

6.79

0.81

Kompolti Hybrid TC

41.5

60.7

5.34

5.15

1.52

7.60

 

Lovrin 110

39.3

66.7

5.85

5.51

 

7.35

 

Moldovan

41.5

66.7

6.08

6.26

1.66

9.15

0.86

Novosadska

35.9

66.3

5.87

4.87

1.73

7.37

0.88

Novosadska plus

29.8

62.2

5.44

5.06

1.64

7.16

0.79

Secuieni 1

40.8

68.4

4.80

3.91

1.80

6.69

0.80

Swissmix

33.7

65.2

7.41

5.91

1.61

7.20

0.83

Uniko-B

37.3

68.6

5.42

4.73

1.60

6.72

0.75

USO 14

27.8

57.1

6.35

5.29

1.61

6.03

0.76

USO 31

38.1

64.0

6.41

5.43

1.58

5.83

0.58

Alp King

28.0

 

 

 

 

 

 

Fedrina 74

35.6

 

 

 

 

 

 

Ferimon 12

37.2

 

 

 

 

 

 

Fibramulta 151

35.0

 

 

 

 

 

 

Helvetica 01

27.5

 

 

 

 

 

 

Helvetica 02

27.1

 

 

 

 

 

 

Helvetica Tell

28.1

 

 

 

 

 

 

Livoniae

32.0

 

 

 

 

7.91

 

Walliser Queen

31.4

 

 

 

 

 

 

*     Mechanical decortication measured according to Keller 1999 (personal communication). Higher numbers indicate easier decortication.
**   Uronic acid content is a marker for pectin content.
***  Pentose content is a marker for hemicellulose content (Leupin 1996).


Fibre production

Traditional breeding in Eastern Europe and France always emphasised fibre production (De Meijer 1995). Cultivars which have a high stem yield, a high bark and fibre content as well as a low stem diameter are generally desirable for this purpose. Additionally, a good decorticability (mechanical separation of the bark from the stem) and a low content of fibre cement substances (so-called "gums", such as lignin, pectin and hemicellulose) are favourable.

In our experiments, the highest stem yields were approximately 13 tons dry matter (DM) per hectare. Late ripening varieties such as 'Kompolti' and 'Fedrina 74' showed a higher stem yield than early ripening varieties like 'USO 14', 'USO 31' and 'Fasamo' (Fig. 2c). The highest fibre and bark contents were measured with Hungarian, Polish, Ukrainian and Yugoslav varieties. Strains originating from Switzerland had a very low bark content (Table 3). The content of fibre cement substances was unclear and varied depending on the cultivar. 'Felina 34' had, for example, a low content of pectin and hemicellulose, but a high lignin content. 'Beniko' has a very low lignin content, but relatively highly pectin and hemicellulose contents. The stem diameter correlated negatively with maturation, late ripening cultivars having thicker stems. This may represent a certain disadvantage for fibre production. 'Fasamo', 'Futura 77' and 'USO 31' were not suited to mechanical decortication (Table 3).

 

Table 4. Grain quality and essential oil smell of different genotypes. Grain characteristics: average 1996-1998 (3 trials), essential oil: average 1996-1997 (2 trials).

 
Genotype

 
Oil

 
Crude

Grains
                                                  Fatty acids (weight-%)                                                

 
Number

Essential oil
smell

  
 
 

content
 
% DM

protein
content
% DM

Palmitic
 
C16:0

Stearic
 
C18:0

Oleic
 
C18:1

Linoleic
 
C18:12

-Linolenic
 
C18:3

-Linolenic
 
C18:3

Eicosenic
 
C20:0

Residue
 
 

Trials
 
 

%*
 
 

Alp King

32.5

30.8

7.1

2.6

10.2

55.2

1.3

21.7

0.4

1.6

1

 

Beniko

29.4

30.2

6.7

2.6

11.1

56.8

3.2

16.9

1.6

1.2

4

40

Bialobrzeskie

35.3

28.1

6.5

3.0

12.1

55.8

2.6

17.5

1.4

1.1

3

65

Fasamo

30.7

30.6

7.0

2.5

10.1

54.5

3.2

19.8

1.7

1.2

4

55

Fedora 19

31.4

28.1

6.5

2.9

11.9

55.7

2.7

17.6

1.2

1.4

6

45

Fedrina 74

33.8

27.5

7.0

2.6

10.3

56.5

1.9

19.7

0.4

1.8

1

 

Felina 34

31.7

26.6

6.4

2.8

11.3

55.8

3.0

18.0

1.4

1.4

5

60

Ferimon 12

33.2

29.6

7.4

2.6

11.6

56.8

2.7

16.6

0.5

2.0

1

55

Fibramulta

 

 

 

 

 

 

 

 

 

 

 

60

Futura 77

33.6

24.1

5.9

2.9

11.3

55.7

2.1

19.8

0.9

1.4

3

60

FxT

31.7

27.1

6.6

2.9

13.1

55.5

1.9

17.8

1.1

1.2

6

50

Helvetica 01

33.2

31.8

6.4

2.4

10.4

55.8

1.2

21.8

0.4

1.7

1

 

Helvetica 02

32.8

31.5

6.4

2.5

10.1

55.5

1.1

22.6

0.4

1.5

1

 

Irene

31.3

30.9

6.2

2.9

14.0

54.5

1.7

18.1

1.6

0.9

3

55

Kompolti

24.9

23.5

6.8

2.7

11.8

55.2

2.0

18.7

1.8

1.0

1

60

Kompolti Hybrid TC

27.7

27.6

6.3

2.9

13.7

54.9

1.8

18.4

1.1

1.2

2

65

Livoniae

33.2

24.9

6.2

2.9

11.7

56.3

2.4

18.5

0.5

1.8

2

40

Lovrin 110

33.1

31.3

6.8

2.5

12.6

56.0

1.6

18.4

1.0

1.1

2

60

Moldovan

34.0

30.7

6.3

2.9

13.0

54.2

2.0

19.1

1.7

0.8

1

65

Novosadska

23.3

28.2

6.6

2.7

12.4

55.4

1.8

18.4

1.7

1.0

1

50

Novosadska plus

19.5

27.3

6.7

2.7

13.6

55.4

1.8

17.3

1.6

0.9

1

55

Secuieni 1

33.4

27.5

6.6

2.8

12.5

55.4

1.7

19.0

0.9

1.3

5

60

Swissmix

29.9

26.6

6.4

2.7

11.5

56.0

1.8

19.5

1.1

1.2

6

55

Uniko-B

32.9

26.6

6.2

2.8

11.8

55.8

1.8

19.8

0.8

1.2

3

50

USO 14

25.9

27.5

7.0

2.8

13.3

55.5

3.4

15.2

1.5

1.3

3

 

USO 31

29.4

28.9

6.6

3.1

13.4

54.8

2.9

16.6

1.5

1.2

3

 

Walliser Queen

29.2

26.3

7.0

2.6

10.3

54.4

1.5

22.1

0.5

1.8

1

 

Average

31.1

28.0

6.5

2.8

12.0

55.6

2.3

18.4

1.2

1.3

 

56

*  Result of smell tests. 100% best, 50% average, 0% very bad


Suitability for the food industry

Hemp seeds are a valuable source of unsaturated fatty acids for human nutrition (Deferne and Pate 1996, Mediavilla et al. 1997). For this use, a high grain yield is desired. At the same time, a low crop height is decisive, because of easier threshing (Bassetti et al. 1998). In our regions, earliness is essential with respect to bird damage. All these characteristics were observed, in particular, on monoecious and early maturing cultivars (Table 2, Fig. 2b). The grain quality characteristics (fat, protein content and fatty acid composition) of different genotypes are represented in Table 4. Seed oil output is important and was higher for early maturing cultivars (between 30 and 36%). The content of gamma-linolenic acid (GLA) was best with the 'USO 14', 'USO 31', 'Fasamo', 'Beniko', 'Felina 34' and 'Fedora 19'. Swiss strains had a lower GLA and a higher alpha-linolenic acid content.

Essential oil of hemp is produced by steam distillation of the inflorescences (Meier and Mediavilla 1997). This essence is used as a taste carrier in some foods (e.g., for beverages and sweets) and cosmetics. The smell quality is more important than the extracted quantity. In our tests, it could be shown that the essential oil produced from 'Felina 34', 'Futura 77', 'Kompolti', 'Kompolti Hybrid TC', Moldovan and 'Bialobrzeskie' was particularly good smelling (Table 4). We suppose that these cultivars would be probably also profitable for the production of hemp beverages (e.g., tea), if they have a low THC content (Fig. 2a).

Conclusion

Hemp varieties differ in their agronomic characteristics and psychoactivity. Important traits include yield and the quality of stems, fibres, grains, GLA and essential oil (Table 2).

The number of varieties suitable for the cultivation is, despite the large number of tested strains, low. Many factors limit the choice in Switzerland. Further restrictions result from the drug law and food regulations. Hemp cultivation in countries recently cultivating hemp (e.g., Canada or Italy) have led to a shortage of available seed. Protectionism by certain breeding organisations can further limit seed production and the commerce. The EU is intending from the year 2001 to allow only varieties with a THC content lower than 0.2%. The effect of these regulations for Switzerland is still open. [Editor's note: See the Letters section concerning EU regulations.]

References

Anonymous 1943. Eidgenössische Landwirtschaftliche Versuchsanstalt Zürich-Oerlikon und Vereinigung "Flachs und Hanf". Anleitung für den Anbau von Flachs und Hanf. [Guidance for the cultivation of flax and hemp] Die Grüne, 1-8. [in German]

Anonymous 1998. Oft wird behauptet, die Resistenz der Hanfpflanzen gegenüber Insekten, Nematoden, Pilzen, Bakterien und anderen Pflanzen sei auf das THC zurückzuführen. Mehrere Arbeiten haben aber gezeigt, dass dies nicht der Fall ist. Erfahrungsgemäss leiden beispielsweise Drogensorten, die nicht an unsere Bedingungen angepasst sind, wenn sie auf dem Feld angebaut werden, unter Krankheiten.

Bassetti, P., V. Mediavilla, E. Spiess, H. Ammann, H. Strasser and E. Mosimann 1998. Hanfanbau in der Schweiz - Geschichte, aktuelle Situation, Sorten, Anbau- und Erntetechnik, wirtschaftliche Aspekte und Perspektiven. [Cultivation of hemp in Switzerland - history, current situation, varieties, cultivation and harvest technique, economic aspects and perspectives.] FAT-Berichte, 516. [in German and French]

Bonin, G., 1994. Hanf Dampf auf allen Äckern. [Hemp steam on all the fields]. Cash. 22:87. [in German]

Bòcsa, I. and M. Karus 1997. Der Hanfanbau - Botanik, Sorten, Anbau und Ernte. [Hemp cultivation - botany, varieties and harvest.] C.F. Müller Verlag, Heidelberg. [in German]

Deferne, J. L. and D. W. Pate 1996. Hemp seed oil: a source of valuable essential fatty acids. Journal of the International Hemp Association 3(1):1-7.

De Meijer, E. P. M., H. J. Van der Kamp and F. A. Van Eeuwijk 1992. Characterisation of Cannabis accessions with regard to cannabinoid content in relation to other plant characters. Euphytica 62:187-200.

De Meijer, E. P. M. 1993. Evaluation and verification of resistance to Meloidogyne hapla chitwood in a Cannabis germaplasm collection. Euphytica 71:49-56.

De Meijer, E. P. M. 1995. Fibre hemp cultivars: A survey of origin, ancestry, availability and brief agronomic characteristics. Journal of the International Hemp Association 2 (2):66-76.

Leupin, M. 1996. Bakterielle Degummierung von Ramie (Boehmeria nivea): I. Erfassung und Beurteilung der Faserqualität, II. Degummierung mit Faserbakterien. [Bacterial degumming of Ramie (Boehmeria nivea): I. Registration and evaluation of the fibre quality, II. Degumming with fibre bacteria.] Doctoral thesis, Swiss Federal Institute of Technology, Zurich, Switzerland, 11 893. [in German]

McPartland, J. M. 1997. Cannabis as a repellent and pesticide. Journal of the International Hemp Association 4 (2):89-94.

Mediavilla, V. and R. Brenneisen 1996. THC-Gehalt von Industriehanf-Sorten. [THC content of industrial hemp varieties.] Mitt Ges. Pflanzenbauwiss. 9:243-244. [in German]

Mediavilla, V., R. Derungs, A. Känzig and A. Mägert 1997. Qualität von Hanfsamenöl aus der Schweiz. [Quality of Swiss hemp seed oil.] Agrarforschung 4 (11-12):445-451. [in German]

Mediavilla, V., M. Jonquera., I. Schmid-Slembrouck and A. Soldati 1998. Decimal code for growth stages of hemp (Cannabis sativa L.). Journal of the International Hemp Association 5 (2):65, 68-74.

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