The Biology of Linum usitatissimum L. (Flax)

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Table of content

1 General administrative information

1.1 Background

The Canadian Food Inspection Agency's Plant and Biotechnology Risk Assessment (PBRA) Unit is responsible for assessing the potential risk to the environment from the release of plants with novel traits (PNTs) into the Canadian environment. The PBRA Unit is also responsible for assessing the pest potential of plant import and plant species new to Canada.

Risk assessments conducted by the PBRA Unit require biological information about the plant species being assessed. Therefore, these assessments can be done in conjunction with species-specific biology documents that provide the necessary biological information. When a PNT is assessed, these biology documents serve as companion documents to Dir94-08: Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits.

1.2 Scope

This document is intended to provide background information on the biology of Linum usitatissimum, its identity, geographical distribution, reproductive biology, related species, the potential for gene introgression from L. usitatissimum into relatives, and details of the life forms with which it interacts.

Such information will be used during risk assessments conducted by the PBRA Unit. Specifically, it may be used to characterize the potential risk from the release of the plant into the Canadian environment with regard to weediness/invasiveness, gene flow, plant pest properties, impacts on other organisms, and impact on biodiversity.

2 Identity

2.1 Name(s)

  • Linum usitatissimum L.

2.2 Family

  • Linaceae, commonly known as the flax family

2.3 Synonym(s)

  • L. crepitans (Boenn.) Dumort. and L. humile Mill (United States Department of Agriculture (USDA-ARS, 2018).

2.4 Common name(s)

  • Linum usitatissimum is commonly known as flax when grown for the fibre extracted from the stem and as linseed or oilseed flax when grown for the oil extracted from the seed.

2.5 Taxonomy and genetics

Linum usitatissimum is one of the nearly 230 species of the family Linaceae which comprises about 14 genera. L. usitatissimum is an annual herbaceous whose genus Linum includes nearly two thirds of the total species of the Linaceae family. Despite this remarkable diversity, flax is the only cultivated species in that family (Bailey 1976; CABI 2018). The USDA-NRCS (2010) taxonomy of flax is as follows:

  • Kingdom: Plantae (plants)
  • Subkingdom: Tracheobionta (vascular plants)
  • Superdivision: Spermatophyta (seed plants)
  • Division: Magnoliophyta (flowering plants)
  • Class: Magnoliopsida (dicotyledons)
  • Subclass: Rosidae
  • Order: Linales
  • Family: Linaceae
  • Genus: Linum L.
  • Species: Linum usitatissimum L.

Flax is a self-pollinated species with a genome size approximately 370 Mb (Ragupathy et al., 2011). The haploid chromosome number of L. usitatissimum is n = 15 (Cloutier et al., 2012). Other species have 8, 9, 10, 14, and 15 pairs (Beard and Comstock, 1965). Colchicine treatments have reportedly caused tetraploidy, phenotypic changes such as sterility and lower yield (Beard and Comstock, 1965), lower seed oil and iodine content (Ross and Boyce, 1946), larger size of petals, pollen grain, seed, and stomata in seed flax, and lower seed size and plant height in fiber flax (Pandey, 1956). World gene banks store approximately 48,000 accessions of flax germplasm (Diederichsen, 2007). In Canada, a world collection of approximately 3,500 accessions of cultivated flax is maintained by Plant Gene Resources of Canada (PGRC, 2018).

2.6 General description

Flax is an erect, herbaceous annual which branches corymbosely above the main stem (Fernald, 1950). Divergent selection applied over thousands of years has resulted in fiber and linseed flax types which are the same species but differ considerably in morphology, anatomy, physiology and agronomic performance (Diederichsen and Ulrich, 2009). The linseed type, grown for oil extracted from the seed, is a relatively short plant which produces many secondary branches compared to the flax type, grown for the fiber extracted from the stem, which is taller and less branched (Gill, 1987). L. usitatissimum has a short tap root with fibrous branches which may extend 90-120 cm in light soils. Leaves are simple, sessile, linear-lanceolate with entire margins, and are borne on stems and branches. The inflorescence is a loose terminal raceme or cyme. Flowers are borne on long erect pedicels, are hermaphroditic, hypogynous and are composed of five sepals, five petals (blue, pink, white), five stamens, and a compound pistil of five carpels each separated by a false septum (Fig. 1 a, b). The fruit is a capsule, composed of 5 carpels and may contain up to 10 seeds (Fig. 1 c). The seed is oval, lenticular, 4-6 mm long with a smooth, shiny surface, and is brown to golden colour. Seeds contain 35-45% oil and 20-25% protein (Gill, 1987; Fernald, 1950).

Flax has been a source of food, feed, fiber, and medicine for more than 8,000 years (van Zeist and Bakker-Heeres, 1975). Linseed oil provides health benefits mainly due to its high content in omega-3 alpha linolenic acid (55-57%). Moreover, linseed oil has valuable attributes in paints and varnishes because of its unique drying properties that result from its distinctive fatty acid composition (Przybylski, 2001). The lignans contained in linseeds have been shown to have beneficial properties against breast, colon, prostate and thyroid cancer, and in lowering relative risk factors for heart disease (Westcott and Muir, 2003). Canada is the first country to allow a health-related claim for flaxseed use on food labels, linking ground whole flaxseed to lower cholesterol (Health Canada, 2014).

3 Geographical distribution

3.1 Native range

Two theories have attempted to explain the origin of Linum. usitatissimum. The first holds that flax was developed from wild species through human selection. L. angustifolium Huds., a wild species prevalent throughout the Mediterranean region, is the most likely progenitor and readily crosses with L. usitatissimum (de Candolle, 1885; and Schilling, 1931). The second holds that cultivated flax arose from polyphyletic activities (Vavilov, 1926).

The contribution of flax to human culture can be traced back over 8,000 years (van Zeist and Bakker-Heeres, 1975). There is a general consensus that the species may have originated in the regions east of the Mediterranean Sea towards India (Vavilov, 1951, Zeven and Zhukovsky, 1975) and spread throughout Asia and Europe, prior to its introduction into the Americas. Flax was first domesticated in the region known as the Fertile Crescent which includes the following modern-day countries of Egypt, Palestine, Israel, Iraq, Syria, Turkey, Iran, Lebanon, Cyprus and Jordan (Fu, 2011). The use of the crop spread in Europe reaching Switzerland and Germany 5,000 years ago (Barber, 1991). Domesticated flax was also cultivated in China and India at least 5,000 years ago (Cullis, 2007). The Phoenicians are believed to have introduced flax to Western Europe through their extensive trading network which had reached as far west as the British Isles. The development of the flax industry in Western Europe was encouraged by policies of Charlemagne (AD 742-814) and later by Napoleon. As colonization of the New World and other regions by European powers occurred, the flax industry spread with it (CABI, 2018).

Fibre flax cultivars are grown in the cool-temperate regions of China, the Russian Federation and Western Europe. Linseed cultivars are grown over a wider area in continental climate regions of Canada, India, China, the United States and Argentina (Green et al. 2008; Marchenkov et al. 2003). In terms of production, Canada is a major producing country along with Argentina, India, the United States, China, Ukraine, Khazkstan, and Russia. Most Canadian flaxseed is exported as linseed (Flax Council of Canada 2015; Marchenkov et al. 2003).

The history of flax across continents is summarized below:

Landmarks in the chronology of flax from ancient to contemporary times (Adapted from Vaisey-Genser and Morris , 2003)

Years B.C.E. (B.C.E. = Before the Common Era)
8000

Wild flaxseed (L. bienne) dated in the Fertile Crescent (Helbaek, 1969; van Zeist, 1970; van Zeist, 1972)

7000

Agriculture fully established in the Fertile Crescent; flax among the first crops domesticated (van Zeist and Bakker-Heeres, 1975; Smith, 1995)

6000

Remains of linen artifacts identified in the Dead Sea area (Schick, 1988)

5000

Earliest dated Egyptian linen cloth (Judd, 1995)

4000

European use of flax: artifacts of the Swiss Lake dwellers (Zohary and Hopf, 1993)

2000

The first industry? Babylonians twisted flax fibers into thread for weaving (Harris, 1993)

1400

Egyptians used linseed oil for embalming and linen for binding mummies (Judd, 1995); linen was the primary fabric for Egyptian cloth (Barber, 1994)

1000

Flaxseed used in breads in Jordan and Greece (Stitt, 1994)

500

Flaxseed used as a laxative and, by Hippocrates, as a poultice ( Judd, 1995); Phoenicians' linen sails may have introduced flax to Flanders and Britain (Wilson, 1979)

Years C.E. (C.E. = Common Era. The Common Era is understood to begin about 1 A.D.)
800

Charlemagne prescribed flaxseed production for all subjects in the Roman Empire (Anonymous, 1999b)

1000

Flanders was a leading centre of the linen industry (Wilson, 1979)

1400

The Renaissance: Van Eyck pioneered linseed oil in oil painting preservation (Judd, 1995)

1500

The Reformation: Huguenots took linen-producing skills to the British Isles (Baines, 1985)

1600

Colonization: French immigrants took flax to North America (Atton, 1989)

1617

Introduction of flax in Canada (New France) by Louis Hébert

1800

Industrial Revolution began. Linoleum flooring patented in Britain (Judd, 1995); invention of the cotton gin in 1793 forecast the end of the dominance of linen and the 1920s' collapse of the flax industry (Duder, 1992)

1980

Consumer emphasis on environmentally friendly, natural products renewed producer interest in flax in North America and Europe (Prentice, 1990)

1995

Emergence of flaxseed as a functional food

3.2 Introduced range

Flax has been observed as far north as 69.7N, 19.0 E in Norway, and in the southern hemisphere, as far south as 49.8S, 72.1W in Argentina. (GBIF, 2018). Flax is currently grown commercially mainly in Western and Eastern Europe, with the largest land areas devoted to flax occurring in Eastern Europe (Russia, Ukraine, Belarus, Poland), but with the best agronomic yields and processing technology in Western Europe (France, Belgium, Netherlands) (FAO, 1994; CABI, 2018). L. usitatissimum was initially introduced to Canada in 1617 by Louis Hébert to New France (Quebec) (Kenaschuk and Rowland 1995; Flax Council of Canada 2015). In the USA, flax production peaked in 1869. However, increasing competition from Gossypium spp. (cotton) and imported Corchorus olitorius (jute) led to the gradual decline of flax production in the USA (CABI, 2018).

Global Distribution of Linum usitatissimum (CABI, 2018)

Asia

Afghanistan, Armenia, Bangladesh, China, India, Iraq, Japan, Kazakhstan, Korea, Kyrgyzstan, Nepal, Pakistan, Turkey, Uzbekistan.

Africa

Egypt, Eritrea, Ethiopia, Kenya, Morocco, Tunisia.

North America

Canada, USA, Mexico.

South America

Argentina, Brazil, Chile, Ecuador, Peru, Uruguay.

Europe

Austria, Belarus, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Germany, Italy, Latvia, Lithuania, Netherlands, Poland, Portugal, Romania, Russian Federation, Slovakia, Spain, Sweden, United Kingdom, Ukraine.

Oceania

Australia, New Zealand.

3.3 Habitat

Globally, the majority (96%) of flax is grown between 49° and 53°N latitude. The plant can grow in other latitudes, such as between 22° and 65°N latitude and 30° and 45°S latitude, but yields of fibre and seed are typically much lower in these other areas. Best performances are obtained in moderate to cool temperature conditions, in northern latitudes receiving 150 to 200 mm rainfall during the main growing period (April-June), in fertile, well-drained, medium- to heavy-textured soils with a pH between 5.5 and 7.0. (CABI, 2018). Outside of cultivation in North America, flax occurs in disturbed areas, roadsides, abandoned homesteads and fields at altitudes between 0–2400 m (eFlora.org, 2018).

4 Biology

4.1 Reproductive biology

Cultivated flax is an annual herbaceous plant that reproduces by means of seed. Because of its perfect flower structure and because its "sticky pollen" is rarely transferred by insects (Beard and Comstock, 1980), flax is a highly self-pollinated species. The pollen is viable for only a few hours, from the time of anther dehiscence until about the time the petals dehisce - between 4 and 7 hours (Lay and Dybing, 1989; Dillman, 1938). As the flower opens, the anthers come together and form a cap over the stigma. Dillman (1938), in studying natural crossing in flax, reported the range of natural outcrossing to be between 0-5%. In over 8,000 observations of the flax variety "Bison", no natural outcrossing was observed.

4.2 Breeding and seed production

Early in the 20th century, only a few Balkan, Russian, and Dutch flax landraces were grown across Europe. The first pure line cultivar, 'J.W.S., was released in 1921 (Dempsey, 1975; CABI, 2018). This period is marked by a substantial increase in breeding activities in Western Europe, especially in the Netherlands where breeding programs focused on breeding white-flowered varieties (CABI, 2018). However in flax, the trait blue flower (corresponding cultivars are sometimes listed as L. usitatissimum var. vulgare) is genetically dominant to the white-flower (corresponding cultivars sometimes listed as L. usitatissimum var. album). Blue-flowered cultivars tend to produce finer fibres, while the white-flowered cultivars tend to be more hardy and disease resistant, and generally produce greater fibre yields (CABI, 2018). Today, breeding efforts in Western Europe focus on disease and lodging resistance, as well as on understanding and breeding for flax that has both high seed oil and high fibre yields (Heyland and Hemkar, 1991; CABI, 2018). In U.S., breeding efforts peaked during World War II, with limited official interest before or since (Hurst et al., 1953; CABI, 2018). In Russia, breeding efforts have stretched throughout the 20th century, and despite the climatic constraints that affect flax quality, years of research have resulted in varieties with good yields of fibre and seed, as well as some resistance to common flax diseases caused by Melampsora, Fusarium and Colletotrichum (CABI, 2018).

The objectives of most breeding programs are: i) to develop and evaluate genetic material to improve agronomic characteristics such as seed yield, oil yield and quality, tolerance to wilt (Fusarium oxysporum f. sp. Lini) and pasmo (Septoria linicola), resistance to known North American races of rust Melampspora sp.), and seed color; ii) to develop and maintain populations with useful genetic variability to support the development of improved cultivars. Most conventional breeding programs follow a pedigree breeding scheme (You et al. 2016).

Today, flax production in Canada is mainly concentrated in the Western provinces of Saskatchewan, Manitoba, and Alberta (Kenaschuk and Rowland, 1995; Flax Council of Canada, 2018a). There once were three major flax breeding programs in Western Canada, namely (i) the Agriculture and Agri-Food Canada (AAFC) program located at the Morden Research and Development Centre in Morden, Manitoba; (ii) the Crop Development Centre (CDC) program located at the University of Saskatchewan in Saskatoon, Saskatchewan; and (iii) the Saskatoon Research and Development facility of Crop Production Services Canada Inc. (CPS), (Duguid 2009; Flax Council of Canada 2018a). These three breeding programs have released 18, 16, and 11 cultivars, respectively, since 1981 (You et al. 2016). In addition to these three western breeding programs, CÉROM (Centre de Recherche sur les Grains), located in Saint- Mathieu-de-Beloeil, Québec, has developed since 2000 a breeding program targeting flax for crop diversification (Flax Council of Canada 2018a). Currently the Crop Development Centre is the sole flax breeding program in the Canadian prairies.

Oil quantity and quality are the primary traits targeted in Canadian breeding programs (You et al. 2016).Most programs aim at optimizing grain yield while maintaining high seed oil (>45%) and alpha-linolenic acid (ALA) content (>50%), resistance to diseases, increased lodging resistance, and shorter time to maturity (Duguid 2009; Hall et al. 2016; Flax Council of Canada 2018a). Between 1910 and 2015, a total of 84 flax cultivars have been registered in Canada. Of these, 58 were developed by Canadian breeders and 24 were introduced from foreign countries. A total of 6, 12, 18, and 23 cultivars were released from 1910–1950, 1951–1980, 1981–2000, and 2001–2015, respectively. Of the total registered cultivars, 72 are linseed, four (J.W.S., Liral Prince, Stormont Motley, and Weira) are fiber types, and six have uncertain end-uses (You et al., 2016). Pedigree data of Canadian flax cultivars were collated in 2016 and their genetic base quantified via pedigree analysis and coefficient of parentage (You et al., 2016). A fairly high mean of coefficient of parentage of 0.14 was observed between all registered cultivars; this value was even higher (0.23) when only the 46 cultivars released from 1981–2015 were considered. The registered cultivars traced back to 46 ancestors; 72% originated from foreign countries and contributed 83% of the genetic base of all cultivars, illustrating the dominant role played by foreign germplasm in the genetic improvement of Canadian flax. The top 11 ancestors contributed 70%–93% of the genetic base of modern flax cultivars released in the last three decades and formed the core gene pool of Canadian flax cultivars. The genetic base of Canadian cultivars is relatively narrow, although it has gradually expanded, especially in the last two decades. Broadening the genetic base through the introduction of new exotic germplasm is needed to invigorate the gene pool of Canadian flax breeding programs.

While many breeding efforts have employed conventional crossing to develop flax, several molecular approaches and technologies have been used including high-density microarray platforms (Fenart et al., 2010), physical and genetic maps (Ragupathy et al., 2011), molecular markers (Kumar et al., 2012), and metabolomics and proteomics (Day et al., 2013). The sequencing of the flax genome (Wang et al., 2012) has also opened the way for flax genomics leading to rapid advances in the structural identification of genes and gene families (Barvkar et al., 2012; Barbu et al., 2012). However, while all of these approaches have allowed the identification of a large numbers of genes potentially involved in a wide variety of different biological processes, the confirmation of their biological role(s) requires functional characterization. Thus, flax has been genetically engineered and a limited number of genes have been up-/down-regulated in this species thereby providing important functional information about the role of these genes in flax (Roach et al., 2011; Wróbel-Kwiatkowska et al. 2007; Day et al., 2009).

4.3 Cultivation and use as a crop

Flax is grown as an oilseed or fibre crop in over 30 countries across the five continents of the world. Oil production is however the dominant component of flax cultivation. In 2014, world production of flax (linseed) was 2.65 million tonnes, led by Canada with 33% of the global total (FAO, 2014). Other major producers were Kazakhstan, China, and Russia. Flax adapts and fits well in various cropping systems and soil types. Flax is the most important industrial fibre crop in Russia where it is grown principally on acidic non-chernozemic soils (pH ≤ 5.5) (Marchenkov et al., 2003). In North America, flax is mainly grown in in the Brown, Dark Brown, Black, and Dark Gray Chernozemic soils of the Canadian Prairies and the southern extensions of these soil zones in the states of North and South Dakota. The flax that is grown on the Prairies is almost exclusively of the oilseed type (Anonymous, 1996). In India, the principal flax-growing zones are the states of Pradesh and Maharashtra where it is grown on black-cotton soils, , Uttar Pradesh and Bihar states on lighter gangetic alluvium soils, and on paddy lands in the Punjab (Gill, 1987). Flax production in China is located in agroecological zones with high elevation (1,000–2,500 m), low annual precipitation (50–500 mm) and low annual temperatures (2.5–10°C) (Pan, 1990). The major factors that affect flax performances are environmental (e.g., drought, waterlogging, high temperature at flowering), ecological (weed pressure), and agronomic management (e.g., weed management, rotations). In the past two decades, the fibre industry has developed some high-value products from linseed stems with applications in the pulp, technical fiber and biofuel industries (Diederichsen and Ulrich, 2009; Cullis, 2011).

4.3.1 Effect of preceding crops on flax

Most research carried out on the Canadian Prairies indicates that previous crop and cropping sequences have a significant impact on flax production and flax yield (Flax Council of Canada, 2018a).

Canola

Flax performs relatively poorly when it succeeds canola or mustard (Brassica) or when it grows along canola volunteer seedlings (Flax Council of Canada, 2018a) This adverse impact of canola on the succeeding flax has been postulated to be the result of the weedy effect of canola volunteers, the allelopathic effect of canola stubble, and the greater exhaustive capacity of canola in terms of soil moisture and nutrients.

Flax

As is the case with most crops (lowest yields and quality occur when seeding on its own stubble), reduced productivity of flax on flax stubble is observed and may be attributed to a build-up of soil pathogens (fusarium wilt and pasmo); a drier seed bed due to reduced soil water storage and conservation; and soil crusting (lower amount of flax residue to protect the soil).

Cereals

Research conducted in western Canada shows that flax responds better on cereal stubble, particularly when it is sown on barley and wheat stubble versus oat stubble.

Legumes

According to the Flax Council of Canada (2018a) citing research conducted in western Canada and North Dakota, flax that succeeds pea has yield similar to flax that succeeds wheat and barley. This may be in part attributed to soil moisture availability and/or the residual nitrogen from the legume.

4.3.2 Plant stand establishment

The recommended optimal plant density in western Canada is 300 plants per square meter (Flax Council of Canada). Lower densities result in loss of yield potential, whereas plant densities above 400 plants/m2 (~ 400 plants/yd2) do not necessarily increase yield and may lead to crop lodging. Optimum seeding rates in rainfed production systems are between 40 and 45 kg/ha (35 and 40 lbs/acre), and 50 kg/ha or 45 lbs/acre in irrigated cropping systems.

4.3.3 Growth and development

The life cycle of the flax plant comprises a vegetative period that lasts between 45 to 60 days and a 15- to 25-day flowering phase, reproductive phase and a maturation period of 30 to 40 days. Although the flax maturity cycle is typically 90 to 125 days, environmental conditions such as cool weather and wet conditions can extend the cycle, whereas drought and high temperature can shorten it (Flax Council of Canada, 2018a).

4.3.4 Crop uses

Flax products have been used by man for over 5000 years. The ancient population used flax for a wide variety of uses including food, illumination, medicine and fiber. Nowadays, food, feed, and industrial uses of flax are prominent.

4.3.4.1. Food

Several food products are manufactured from flax seed including breads, cereals, crackers, energy bars, meal, mixes, oil, omega-3 eggs, pasta, snacks, and waffles (Flax Council of Canada (2018b). Flaxseed sprouts are edible, with a slightly spicy flavor. In northern India, flaxseed, called tisi or alsi, traditionally is roasted, powdered, and eaten with boiled rice, a little water, and a little salt (Chopra et al., 1933). Flaxseed is a source of carbohydrates, fats, proteins, vitamins, and minerals (Table 2).

Table 2. Nutritional value per 100 g (3.5 oz) of flaxseed. Percentage values are rough approximation of US adult recommendations
Energy 2,234 kJ (534 kcal)
Carbohydrates 28.88 g
Sugars 1.55 g
Dietary fiber 27.3 g
Fat 42.16 g
Saturated 3.663 g
Monounsaturated 7.527 g
Polyunsaturated 28.730 g
omega-3 22.8 g
omega-6 5.9 g
Protein 18.29 g
Vitamins
Thiamine (B1) 1.644 mg (143%)
Riboflavin (B2) 0.161 mg (13%)
Niacin (B3) 3.08 mg (21%)
Pantothenic acid (B5) 0.985 (20%)
Vitamin B6 0.473 mg (36%)
Folate (B9) 0 μg (0%)
Vitamin C 0.6 mg (1%)
Minerales  
Calcium 255 mg (26%)
Iron 5.73 mg (44%)
Magnesium 392 mg (110%)
Phosphorus 642 mg (92%)
Potassium 813 mg (17%)
Zinc 4.34 mg (46)

USDA Database entry

Units

  • μg = micrograms
  • mg = milligrams
  • IU = International units

Percentages are roughly approximated using US recommendations for adults.

Source: USDA Nutrient Database

4.3.4.2 Feed

Traditionally, flax is crushed to produce linseed oil for industrial applications, and the resultant flaxseed (also called linseed) meal is used as a protein supplement in livestock feeds. Some studies have reported that products, such as eggs and beef, from animals-fed flax have increased levels of omega-3 fatty acids (Scheideler et al., 1994; Maddock et al., 2003).

Nutritive value of flax

Similar to most grains and oilseeds, the composition of flax can vary based on variety, environmental factors and method of analysis (Daun et al., 2003). Most commonly used data regarding the nutritive value of flax are 41 percent oil, 20 percent protein and 28 percent dietary fiber (Canadian Grain Commission, 2001; DM basis). Reported protein values range from 18.8 percent to 24.4 percent (Daun and Pryzbylski, 2000).

When compared to other oilseeds (Table 3), flax falls between soybeans and sunflowers (oil type) in energy content and is similar to sunflowers, canola and cottonseeds for crude protein content. The amino acid composition of flax is similar to soybeans (Table 4).

With respect to alphalinolenic acid (ALA), an essential omega-3 fatty acid that is a precursor for eicosapentaenoic acid (EPA), which in turn is a precursor for the formation of eicosanoids (Eicosanoids are hormone-like compounds that play an essential role in immune response), a summary of data from the Flax Council of Canada (1997) and the NRC (1998) by Maddock et al. (2005) indicates that the ALA content is about five times higher in flax oil than in canola and soybean oils; and more than ten times higher in comparison to sunflower and cottonseed oils.

Table 3 Nutrient content of flaxseed, canola, soybean, sunflower, and cottonseed (DM basis) (Maddock et al., 2005)
Flax Table Note 1 Canola Table Note 1 Soybean Table Note 1 Sunflowers Table Note 1 Table Note 3 Cottonseed Table Note 2
DM (%) 94 92 90 94 91
TDN (%) 110 115 91 121 95
NEm (Mcal/kg) 2.82 2.95 2.11 3.12 2.38
CP (%) 22.8 21.0 41.7 17.9 23.0
Lipid (%) Table Note 4 35.0 40.0 18.8 41.0 17.5
ADF (%) 8.0 12.0 10.0 39.0 40.0
Ca (%) 0.26 0.35 0.27 0.18 0.16
P (%) 0.56 0.68 0.63 0.56 0.62

Table Notes

Table note 1

Adapted from Alternative Feeds for Ruminants, Lardy and Anderson, 1999 (except lipid).

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Table Note 2

NRC, 1996.

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Table Note 3

Sunflowers are oil type.

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Table Note 4

Lipid percentages are adapted from McDonald, 1994 (except soybeans and cottonseed, which were adapted from NRC, 1996).

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Table 4. Amino acid composition of flaxseed, soybean, and sunflower (g/100 g protein) (Maddock et al., 2005)
Flax Table Note 5 Soybean Table Note 6 Sunflowers Table Note 6
Arginine 9.2 7.32 8.18
Cystine 1.1 1.5 1.77
Histidine 2.2 2.77 2.60
Isoleucine 4.0 4.56 4.09
Leucine 5.8 7.81 6.41
Lysine 4.0 6.29 3.56
Methionine 1.5 1.44 2.29
Phenylalanine 4.6 5.26 4.62
Threonine 3.6 3.96 3.72
Tryptophan 1.8 1.26 1.19
Valine 4.6 4.64 4.95

Table Notes

Table Note 5

Adapted from Oomah and Mazza, 1993.

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Table note 6

Adapted from NRC, 2001.

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Regarding the vitamin content, flaxseed meal is lower in choline and higher in thiamin than soybean meal or sunflower meal; it is similar to soybean meal in most other vitamins (Table 5) (Maddock et al., 2005). Flax is similar to soybeans in mineral content, with the exception that flax is much lower in potassium. Flax also is higher in magnesium than either soybeans or cottonseed (Table 6) (Maddock et al., 2005).

Table 5. Vitamin content of flaxseed, soybean, and sunflower meals (mg/kg as fed) (Maddock et al., 2005)
Flax Soybean Sunflower
Biotin 0.41 0.26 1.45
Choline 1512 2731 3150
Folacin 1.30 1.37 1.14
Niacin 33 22 220
Pantothenic Acid 14.7 15.0 24.0
Riboflavin 2.9 3.1 3.6
Thiamin 7.5 3.2 3.5
Vitamin B6 6.0 6.4 Not given
Vitamin E 2.0 2.3 9.1
Beta Carotene 0.2 0.2 0.0

Adapted from Nutrient Requirements of Swine (NRC, 1998).

Table 6. Mineral content of flaxseed, cottonseed, and soybean oils (dry matter basis) (Maddock et al., 2005)
Flax Table Note 7 Cottonseed Table Note 8 Soybean Table Note 8
Calcium, % 0.24 0.16 0.27
Magnesium, % 0.43 0.35 0.27
Phosphorus, % 0.62 0.62 0.65
Potassium % 0.83 1.22 2.01
Copper, ppm 10 10 20
Iron, ppm 50 160 180
Manganese, ppm 30 10 40
Sodium, ppm 270 300 400
Zinc, ppm 40 40 60

Table Notes

Table Note 7

Adapted from the Flax Council of Canada, 1997.

Return to table note 7  referrer

Table note 8

NRC, 1996.

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4.3.4.3. Industrial use

The primary industrial use for flaxseed other than seed for planting is for processing to obtain linseed oil and linseed meal.

Linseed oil can be used as a drying oil vehicle in paints, varnishes, lacquers, enamels, oilcloth, linoleum, oil clothing, tarpaulins and tenting, patent leather, textiles, printing inks, soap, shoe polish and other specialty items.

Linseed meal is a byproduct of flaxseed after it is crushed for linseed oil. The product is used as a high-protein animal and poultry feed. Linseed meal has a unique combination of amino acids in the protein, which produces a glossy, healthy coat for animals. Because of this, horse breeders throughout the United States use linseed meal.

Flax is also grown for the fiber produced from the stem of the plant. The fiber is processed to make the finest paper and linen products. High-quality flax line fibers are used in applications where strength and fineness are desired. Such uses include fine linens, clothing, draperies, furniture, lace and thread. Coarser grades are used where strength is important, but where fabric fineness is not as crucial, such as twine, canvas and bags. The short tow fibers are often used in high-quality paper, such as for cigarettes, writing paper and currency. Newer applications include composite panels for 'recyclable' automobile construction. Because of the durability of the fiber, it is also used to make mulches for horticultural use.

4.4 Gene flow during commercial seed and biomass production

Gene flow during commercial seed and biomass production can occur directly through pollen transfer (Pollen-mediated gene flow or PMGF) or through contamination of sowing seeds, inadvertent admixture of seeds during sowing, harvest or transport, and gene persistence in volunteer populations (Seed-mediated gene flow or SMGF) (Jhala et al., 2010; Dexter et al., 2010ab). PMGF in flax depends on the position of anthers in relation to the stigma, receptivity of the stigma, viability of pollen, and availability of pollinators (Henry and Tu, 1928; Yermanos and Kostopoulos, 1970), but may also vary with genotype and environment (Dillman, 1938). Previous reports have indicated outcrossing rates in flax in the range of 1–5%, when flax plants were grown in close proximity (Howard et al., 1919; Graham and Roy, 1924; Bolley, 1927; Dillman and Stoa, 1935; Dillman and Goar, 1937; Joshi, 1994). Field experiments conducted in western Canada and aiming at quantifying pollen-mediated gene flow between two cultivars of flax showed that the frequency of gene flow was highest near the source: averaging 0.0185 at 0.1 m but declined rapidly with distance to 0.0013 and 0.00003 at 3 and 35 m, respectively (Jhala et al., 2011). Gene flow was reduced to 50% and 90% between 0.85 to 2.64 m, and 5.68 to 17.56 m, respectively. No gene flow was detected at any site or year > 35m distance from the pollen source, suggesting that frequency of gene flow was ≤ 0.00003 (P = 0.95). While PMGF could contribute to adventitious presence of a PNT, isolation distances between fields are usually sufficient to reduce adventitious presence from PMGF below the 0.9% labeling threshold for adventitious presence of approved traits by the European Union (Beckie and Hall 2008; Devos et al. 2009). Because SMGF involves several components of production systems (seeding, harvesting, transportation, etc…) and occurs over time, it is more complex and is more difficult to mitigate.

4.5 Cultivated L. usitatissimum as a volunteer weed

Volunteer flax is a common weed in fields where flax crop is grown in western Canada and it had been ranked as the 26th most abundant weed (Leeson et al. 2005). Volunteer flax emerges over an extended period of time during the growing season with 50% emergence occurring after the in-crop herbicide application (Dexter et al. 2010a). The population densities of volunteer flax ranged from 31 to 4,597 plants m-2 in 20 commercial fields surveyed in the Canadian Prairies. Naked seeds and flax seed bolls can be lost before or after harvest and are the primary contributor to the seed bank and the reason for volunteer persistence over time. In a study conducted in 10 commercial fields in Alberta, Dexter et al. (2011) reported higher seed losses associated with direct harvesting methods when compared to the windrow harvest methods. The maximum yield loss was found to be 44 kg ha-1 or 2.3% of the estimated crop yield. With respect to seed persistence in the soil, it varied with years and the burial depth (longer seed persistence at 10 cm). In a survey of 20 Western Canadian fields following flax production, volunteers continued to emerge in some fields for three growing seasons at low densities (Dexter et al. 2010a). Cultural, mechanical, chemical, and integrated strategies can be used to control volunteer flax.

4.5.1 Cultural/mechanical control

Tillage and fire are common practices used for weed management. For instance, in Russia where fibre flax production is prominent, plowing and incorporation of residues are carried out in the fall, whereas harrowing is achieved in the spring (Marchenkov, 2003). In contrast to the situation with fibre flax production in Russia, oilseed flax on the Canadian Prairies usually follows a cereal or legume crop and therefore the tillage practices are less intensive. Fall tillage on the Prairies to prepare land for flax seeding has become less common in recent years and is primarily used as a tool for controlling weed through harrowing.

4.5.2 Chemical control

Because flax is a broadleaf species, control of volunteer flax in field crops is particularly difficult to achieve. However, the Saskatchewan Flax Development Commission (2018) recommends the use of quinclorac herbicide which provides excellent control of volunteer flax in wheat. Products or mixtures that contain dichlorprop will provide some suppression of volunteer flax in cereal crops. Use the maximum recommended rates. Products that include 2,4-D LV ester will have slightly more effect on the flax than 2,4-D amine or MCPA.

4.5.3 Integrated weed management

Because of the poor level of control likely to be achieved with herbicides, cultural practices are important in minimizing problems caused by volunteer flax. A competitive cereal crop managed for maximum competitiveness (early, shallow seeding; adequate, banded fertilizer; maximum seeding rate for the area) and treated with one of the herbicides mentioned above should maximize the level of suppression.

4.5.4 Biological control

Bio-preparations, chitosan and its derivatives have been shown to exhibit fungicidal properties against soil-borne fungus that infect flax seeds (Wielgusz et al., 2010). Thus, Pythium oligandrum displayed greater seed protection than the control fungicide; Pseudomonas aureofaciens and P. fluorescens generally produced similar control as the fungicide control; and Chitosan and its derivatives provided a lesser level of control than the fungicide control.

4.6 Means of movement and dispersal

Flax plants disperse their seeds through their own agency (Horwood and Fitch, 2016). When the 5-celled fruit is ripe and dry, the capsule opens by 10 slits and the seeds are dispersed around the parent plant. The outer seed coat swells when moistened and produces mucilage which glues the seed to the ground. Due to its ability to absorb and maintain water, the hydrophilic mucilage is responsible for specific surface properties which are essential for seed dispersal in different ways. It is still unclear if it spreads by other means. However results from laboratory experiments have suggested that fully hydrated mucilage with its low viscosity gives optimal sliding conditions for endozoochory, whereas water loss provides conditions for the epizoochory (Kreitschitz et al. 2015). L. usitatissimum and its progenitors are plants of disturbed habitats. In unmanaged ecosystems these species may be considered as "primary colonizers", i.e., plant species that are the first to take advantage of disturbed land where they would compete against plants of similar types for space. Unless the habitats are disturbed on a regular basis, such as on cliff edges, open sites where soil is light or sandy and windblown, river edges and the edges of pathways made by animals, populations of these types of plants will become displaced by intermediaries and finally by plants that will form climax ecologies such as perennial grasses on prairies and tree species and perennial shrubs in forests.

5 Related species of L. usitatissimum

Table 7. The Linum genus and occurrences. (Adapted from Scoggan (1978); eFloras.org; and Canadensys)
Species Ploidy (2n) Occurrence
Linum alatum ("Winged flax") 30 TX, LA (1 occurrence)
Linum allredii ("Allred's flax") ? NM, TX
Linum arenicola ("Sand flax") 36 FL
Linum aristatum ("Bristle or Broom flax") 30 AZ, CO, NM, TX, UT; Mexico
Linum austral ("Southern flax") Table Note 9 Table Note 10 ? AB, MT, WY, CO, NM
Linum australe var. australe Table Note 9 Table Note 10 ? AB, MT, WY, CO, NM, AZ, UT, NV, Mex
Linum australe var. glandulosum ? AZ, TX, Mex
Linum berlandieri (Berlandier yellow flax" 30 CO, NM, TX, NE, KS, OK, LA, AR, Mex
Linum bienne ("Pale flax") aka Linum angustifolium Table Note 10 30 BC, CA, OR, PA, Europe, N. Africa, New Zeland, Argentina, Chile
Linum carteri (Carter's flax") 60 FL
Linum catharticum ("fairy or purging flax") Table Note 10 16 BC, NB, NL, NS, ON, PE, QC, ME, MA, MI, NH, NY, PA, VT, Europe, Asia, Arg, Aust, NZ
Linum compactum ("Wyoming flax") aka Linum rigidum Table Note 10 30 AB, SK, CO, IL, KS, MO, MT., NB., NM, ND, OK, SD, TX, WY
Linum elongatum ("Laredo flax") 30 TX, Mex
Linum floridanum ? TX, LA, MS, AL, GA, FL, SC, NC, VA, Jamaica
Linum grandiflorum ("Crimson flax") 16 CA, CO, FL, KY, NE, NY, OH, PA, TX, UT; N Africa.
Linum harperi ("Harper's flax") 30 Al, FL, GA
Linum hudsonioides ("Texas flax") 30 KS, NM, OK, TX
Linum imbricatum ("Tufted flax") 30 LA., OK, TX
Linum intercursum ("Sandplain flax") 36 Al, CT, DE, DC, GA, IN, MD, MA, NJ, NY, NC, PA, RI, SC, TN, VA
Linum kingii ("King's flax") 26 CO, ID, NE, UT, WY
Linum lewisii ("Wild blue flax") Table Note 10 18 Across Canada and US
Linum lundellii ("Sullivan City flax") 30 TX, Mex
Linum macrocarpum ("Spring Hill flax") ? AL., FL, LA, MS
Linum medium ("Stiff Yellow flax") Table Note 10 ? ON, Mid-W, US, East US, South-East US, Bahamas
Linum neomexicanum ("New Mexico Yellow flax") 26 AZ, NM; Mex
Linum perenne ("Blue flax") Table Note 10 18 BC, ON, YT; AZ, CO, ID, IL, IA, ME, MI, MT, NE, NV, NY, OH, OR, PA, UT, VA, WV, WI; Eurasia; Mex
Linum pretense ("Meadow flax") 18 AZ, CO, KS, NM, OK, TX
Linum puberulum ("Plain flax") 30 AZ, CA, CO, NE, NV, NM, TX, UT, WY; Mex
Linum rigidum ("Stiffstern flax" aka linum compactum) Table Note 10 30 AB, SK, MB, Mid-West US, Mex
Linum rupestre ("Rock flax") 36 NM, TX; Mex, Guatemala
Linum schiedeanum ("Schiede's flax") 36 NM, TX, Mex
Linum striatum ("Ridged Yellow flax") Table Note 10 36 ON; AL, AR, CT, DL, DC, FL, GA, IL, IN., KY, LA, MD, MA, MI, MS, MO, NJ, NY, NC, OH, OK, PA, RI, SC, TN, TX, VA, WVA.
Linum subtrees ("Sprucemont flax") 30 AZ, NV, NM, UT
Linum sulcatum ("Grooved Yellow flax") Table Note 10 30 MB, ON, QC; AL, AR, CT, FL, GA, IL, IN, IA, KS, KY, LA, MD, MS, MI, MN, MS, MO, NE, NH, NJ, NY, NC, ND, OH, OK, PA, RI, SD, TN., TX, VT, VA, WVA, WI
Linum trigynum ("French flax") 20 CA, Europe, Asia, Africa, Hawaii, New Zealand, Australia
Linum vernale ("Red-eye flax") 30 NM, TX; Mex
Linum virginianum ("Woodland flax") Table Note 10 36 ON, AL, CT, DE, DC, GA, IL, IN, IA, KY, MD., MA., MI, MO, NJ, NY, NC, OH, PA, RI, SC, TN, VA., WVA
Linum westii ("West's flax") 36 FL

Table Notes

Table note 9

Occurrence reported exclusively by eFlora.org.

Return to table note 9  referrer

Table note 10

Canadian occurrences.

Return to table note 10  referrer

5.1 Inter-species/genus hybridization

Important in considering the potential environmental impact following the unconfined release of genetically modified L. usitatissimum is an understanding of the possible development of hybrids through interspecific and intergeneric crosses between the crop and related species. Development of hybrids could result in the introgression of the novel traits into these related species and resulting in:

  • the related species becoming more weedy
  • the introduction of a novel trait with potential for ecosystem disruption into the related species

The genus Linum, to which L. usitatissimum belongs, contains approximately 230 species differing in chromosome number from 2n = 16, 18, 30, 36 and 60 (Seetharam, 1972). Among nine Linum species with chromosome 2n = 30, Gill and Yermanos (1967a) reported the following successful hybridization events with L. usitatissimum as one of the parents:

  • L. usitatissimum x L. angustifolium
  • L. usitatissimum x L. africanum
  • L. corymbiferum x L. usitatissimum
  • L. usitatissimum x L. decumbens
  • L. nervosum x L. usitatissimum
  • L. pallescens x L. usitatissimum

Seetharam (1972) reported the following successful crosses among Linum species with 2n = 30:

  • L. angustifolium x L. usitatissimum
  • L. hirsutum x L. usitatissimum
  • L. floccosum x L. usitatissimum
  • L. tenue x L. usitatissimum
  • L. africanum x L. usitatissimum
  • L. pallescens x L. usitatissimum

And, Bari and Godward (1970) the following:

  • L. africanum x L. usitatissimum
  • L. pallescens x L. usitatissimum

Seetharam (1972) attempted crosses between different species having different chromosome numbers, but without any success. Gill and Yermanos (1976b) reported similar results. Hybridization of flax with many other wild relatives has either not been studied or reported.

5.2 Potential for introgression of genetic information from L. usitatissimum into relatives

Based on cytogenic and hybridization studies between flax and wild or weedy relatives, gene flow between flax and related species is possible in in North America, depending on species distribution, sympatry, concurrent flowering, ploidy level, and sexual compatibility (Jhala et al., 2008). Out of the nine related species that have been successfully crossed with L usitatissimum (L. pallescens, L. africanum, L. tenue, L. floccosum, L. hirsutum, L. angustifolium, L. nervosum, L. decumbens, L. corymbiferum),Linumangustifolium, also known as Linum bienne or pale flax, is the only one that grows in Canada, in British Columbia where it had been introduced (eFlora.org, 2018a; Brouillet et al., 2010+). There are two additional related species, with the same chromosome number as L. usitatissimum (2n = 30) that grow in Canada: Linum rigidum, also known as Linum compactum, and Linum sulcatum. These two species have the potential to hybridize with L. usitatissimum.

L. bienne is thought to be the progenitor of L. usitatissimum (Ockendon, 1971). Given that the flowering periods of L. bienne and L. usitatissimum overlap, and that artificial hybridizations between the two species have been shown feasible, gene flow between the two species is likely, in natural or semi-natural environments, if the two species are in close proximity. Jhala et al. (2011) have demonstrated that pollen-mediated gene flow between two cultivars of flax was possible when they were within a radius of 35 m from each other.

Regarding L. rigidum and L. sulcatum, there are no reports of hybridization with L. usitatissimum. However, because the two species are related and possess the same number of chromosomes as L. usitatissimum, the possibility of natural hybridization in Canada cannot be discarded, notably in the three Prairies provinces (AB, SK, MB) where Linum rigidum is reported as a native species (Brouillet et al., 2010+), and in Ontario and Quebec where L. sulcatum occur.

5.3 Summary of the ecology of relatives of Linum usitatissimum

Linum bienne grows in British Columbia where it has been introduced. It flowers between March and August in grasslands, woodlands, and disturbed ecosystems (eFlora.org, 2018a).

Moss (1983) reported L. rigidum, a large, yellow-flowered annual, on open slopes and grasslands of southern Alberta. It has also been reported on dry open soil in Manitoba (Fernald, 1950). Budd (1987) reported L. rigidum on sandhills and on very light sandy soils. Scoggan (1978) reported a similar distribution.

Linum sulcatum grows in Manitoba, Ontario, and Quebec where it flowers between May and September on sandy, gravelly fields, calcareous ledges and barrens, diabase barrens, cedar glades, prairies, alvars, sometimes in open woods, interdunal flats; at 0 to 800 m elevation (eFlora.org, 2018b)

6 Potential interaction of Linum usitatissimum with other life forms

Table 1. Examples of potential interactions of Linum usitatissimum with other life forms during its life cycle in a natural environment

Fungus
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Alternaria linicola J.W. Groves & Skolko ;
A. alternata, (Fr.: Fr.) Keissl. and
A. infectoria E.G. Simmons
(Alternaria Blight)
Pathogen Present Rashid (2003)
CABI (2018)
Botryotinia fuckeliana (de Bary) Whetzel
Syn.: Botrytis cinerea Pers.: Fr
(Gray Mould)
Pathogen Widespread Rashid (2003)
AAFC (2013)
Colletotrichum lini (Westerdijk) Tochinai,
Syn.: C. linicola Pethybr. & Lafferty
(Anthracnose)
Pathogen Present (AB, MB, ON, SK) Rashid (2003)
AAFC (2013)
Discosphaerina fulvida (Sanderson) Sivan.
Syn.: Aureobasidium pullulans var. lini (Lafferty) W.Cooke; Polyspora lini Lafferty.
(Stem Break and Browning)
Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
(CABI 2018)
Fusarium oxysporum f.sp. lini (Bolley) Snyder & H.N. Hansen(Fusarium Wilt) Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
CABI (2018)
Fusarium; Pythium;
Rhizoctonia solani J.G. Kühn
(Seedling Blight and Root Rot)
Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
AAFC (2013)
Melampsora lini (Ehrenb.) Lév.
(Flax rust)
Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
AAFC (2013)
Oidium lini Skoric
(Powdery Mildew)
Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
AAFC (2013)
Mycosphaerella linicola NaumovSyn.: Septoria linicola (Speg.) Garass.(Pasmo) Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
AAFC (2013)
Sclerotinia sclerotiorum (Lib.) de Bary
(Sclerotinia Stem Rot)
Pathogen Widespread Flax Council of Canada (2018a); Rashid (2003)
AAFC (2013)
Verticillium dahliae Kleb; Verticillium albo-atrum Reinke & Berthold.
(Verticillium Blight)
Pathogen Widespread Rashid (2003)
AAFC (2013)
Phytoplasma
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Aster Yellows Pathogen (Transmitted by the six-spotted leafhopper (Macrosteles fascifrons Uhl.)) Widespread Flax Council of Canada (2018a); Rashid (2003)
AAFC (2013)
Virus
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Oat blue dwarf virus (OBDV)
Crinkle
Pathogen (Transmitted by the six-spotted leafhopper (Macrosteles fascifrons Uhl.)) Present (MB) Flax Council of Canada (2018a)
AAFC (2013)
BCTV
The Beet Curly Top Virus (BCTV)
Pathogen (transmitted by the leafhopper (Eutettix tenellus Baker) Present (BC, NB, ON) Rashid (2003)
AAFC (2013)

Insects

Belowground and seedling feeders
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Agrotis orthogonia Morrisson
Pale western cutworm
Pest (consumer) of flax (Hall et al. 2016). Present in the prairie regions of AB SK MB (MPG 2014). Flax Council of Canada (2018a)
Euxoa auxiliaris (Grote)
Army cutworm
Pest (consumer) of flax (Hall et al. 2016). A migrant from AB to SK and rarely to MB, though not at economic levels in MB (Cutworms In Field Crops). Present in AB and SK (MPG 2014). Flax Council of Canada (2018a)
Euxoa ochrogaster (Guenée)
Redbacked cutworm
Pest (consumer) of flax (Hall et al. 2016). Present, widespread in Canada (MPG 2014). Flax Council of Canada (2018a)
Euxoa tristicula (Morrison)
Early cutworm
Pest (consumer) of flax (Hall et al. 2016). Present, widespread in suitable habitat (MPG 2014).
Wireworms, e.g. Agriotes lineatus (L.) (lined click beetle), Agriotes obscurus (L.) (the dusky wireworm), Agriotes sputator L. (common click beetle) Pest (consumer) of flax (Gavloski et al. 2011). Present. A. lineatus and obscurus: BC, NS, PE, NF, A. sputator: NB, NS, PE (Bousquet et al. 2013). Flax Council of Canada (2018a)
Sap feeders
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Macrosiphum euphorbiae (Thomas)
Potato aphid
Pest (consumer) of flax (Hall et al. 2016). Particularly damaging to the boll, causing reductions in flax yield (Gavloski et al 2011). Present and widespread in Canada (Maw et al. 2000). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Lygus lineolaris (Palisot de Beauvois)
Tarnished plant bug
Pest (consumer) of flax (Hall et al. 2016). Replaced in importance by other Lygus species (L. keltoni, L. elisus) depending on local climatic conditions (Gavloski et al 2011). Present and widespread in Canada (Maw et al. 2000). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Macrosteles quadrilineatus Forbes
Aster leafhopper
Pest (consumer) of flax (Hall et al. 2016). An introduced species, and a generalist feeder: it is of
economic importance in flax because of its potential to vector aster yellows (Candidatus
phytoplasma asteris; Gavolski et al 2011).
Present and widespread in Canada (Maw et al. 2000). Flax Council of Canada (2018)a
Wise and Soroka, (2003)
Thrips linarius Uzel Not reported in Canada, but present in Europe to Russia. Wise and Soroka, (2003)
Defoliators
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Heliothis ononis Denis and Schiffermüller
flax bollworm
Pest (consumer) of flax (Hall et al. 2016). High populations are sporadic, and populations are usually kept low by parasites and diseases (Gavloski et al 2011). Primarily in SK and AB (MPG 2014). From south-central MB west to BC, north to NWT and YK, and AK and south to CO. Also found in Eurasia (U. of Alberta 2014). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Melanoplus bivittatus (Say)
Twostriped grasshopper
Pest (consumer) of flax (Gavloski et al. 2011). Present and widespread in Canada to Mexico (Belov and Moisset 2018). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Mamestra configurata Walker
Bertha armyworm
Caterpillar
Pest (consumer) of flax (Hall et al. 2016). Feeding on flax can be damaging when late-instar larvae feed on the flowers and immature capsules (Gavloski et al 2011). Present BC to MB (Mason et al 2012). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Loxostege sticticalis L.
Beet webworm
Pest (consumer) of flax (Hall et al. 2016). Larvae are migratory and will move to new fields once one is destroyed (Gavloski et al 2011). Present. Widely distributed throughout the Nearctic and Palaearctic regions. In North America, across Canada, north into the Northwest Territories and the Yukon, south to Arizona (U. of Alberta 2014). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Anarta trifolii (Hufnagel)
Syn.: Discestra trifolii
Nutmeg moth or clover cutworm
Pest (consumer) of flax, albeit occasional (Gavloski et al. 2011). Present and widespread in Canada and across the global temperate zone (Belov and Moisset 2018). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Melanchra picta (Harris)
Zebra caterpillar
Not a significant pest of flax (Flax Council of Canada 2018). Present across southern Canada (MPG 2014, Belov and Moisset 2018). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Euptoieta claudia (Cramer)
Variegated fritillary
Pest (consumer) of flax (Gavloski et al. 2011), but usually not numerous enough to be significant (Flax Council of Canada 2018). Present across southern Canada as a summer migrant from the southern US (MPG 2014, Belov and Moisset 2018). Flax Council of Canada (2018a)
Wise and Soroka, (2003)
Aphthona euphorbiae Schrank
Large flax flea beetle
No evidence to suggest presence in North America. Was not found in previous PHRA documents. Not reported in Canada, but present in Europe. Wise and Soroka, (2003)
Longitarsus
parvulus Paykull
Flax flea beetle
No evidence to suggest presence in North America. Was not found in previous PHRA documents. Not reported in Canada, but present in Europe. Wise and Soroka, (2003)
Midges
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Dasyneura lini Barnes
Linseed blossom midge or bud fly
No evidence to suggest presence in North America. Was not found in previous PHRA documents. Not reported in Canada.
Present in India
Wise and Soroka, (2003)
Plant
Other Life Forms Interaction with L. usitatissimum (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Linum angustifolium, aka Linum bienne Gene transfer Present (eFlora.org, 2018a; Canadensys, 2018)
Linum rigidum, aka Linum compactum Potential gene transfer Present Moss (1983); (Fernald, 1950);

7 References

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