Helianthus annuus

• English: sunflower
• French: tournesol

see more European names

A striking feature of sunflowers is that all flowering heads seem to look eastwards. The young plant, before flower opening, looks eastwards in the early morning, and follows the sun during the day. At night, it comes back to its original position. But when flowers open, they stop eastwards.

• subsp. lenticularis (Dougl.) Cockerell (1914) is the wild form from western North America. It has many branches with small heads.
• subsp. annuus var. annuus is a weedy form from eastern North America.
• subsp. annuus var. macrocarpus (DC). Cockerell (1914) includes cultivated forms, which have only one stem and a terminal big head.

• Cultivars used for their seeds eaten as snacks have usually big heads and big akenes striped with brown and white.
• Cultivars grown for the extraction of oil have small heads and small black akenes.
  • Usual oil sunflower cultivars give an oil with 24% oleic acid and 65% linoleic acid.
  • High oleic cultivars give an oil with 50% to 90% oleic acid. They must be grown in isolation from usual cultivars (more than 500 m apart) because pollen contamination would cause a lower oleic acid content.
• Ornamental cultivars show flowers with diverse colors, or double flowers. Many cultivars are interspecific hybrids.

Domestication in North America

Sunflower has been domesticated by Amerindians. They used the seeds either roasted or crushed into a paste. This paste had a cosmetic use, or was mixed with maize flour into cakes. But oil was not extracted.

The plant was grown as individual plants near or in maize fields. Cultivars with high stem and big heads were selected.

Introduction to Europe in the 16th century

• Historical illustrations
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  Chrysanthemum perunianum (Dodoens 1568)

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  Chrysanth. perunianum (Dodoens 1569)

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  Chrysanthemum peruvianum (Dodoens 1583)

Dodoens's illustrations from the same wood engraving. It represents a cultivated type with only one big head. Leaves are drawn as alternate, although they are in fact opposite decussate.

During centuries, sunflower was grown as an ornamental. Targioni-Tozzetti mentions it as an ornamental, and Candolle omits it because he did not deal with ornamentals.

The use as poultry feed may have begun then, and is still practiced up to now (as entire heads).

Adoption as an oil crop in Russia

This change is largely due to the Orthodox Church ! There were then long periods of fast, during Lent and Christmas. A long list of prohibited oil-rich foods was compiled in the 18th century, but sunflower oil was not on the list, as it was new and unknown. Farmers began growing the plant in Ukraine and Kuban, and the first crushing factories were created in 1830.

In the first half of the 20th century, Russian breeders improved the oil content, and choosed a cultivar-type with small stem and medium-sized head. Russian cultivars began spreading to western Europe. It is said that Hitler invaded the Soviet Union partly to have access to sunflower oil, because Germany eagerly needed cooking oil.

Discovery of a male-sterility character in France

In the second half of the 20th century, Europe (and particularly France) began investing in research in "metropolitan" oil crops, as it could no longer rely on tropical oils. In 1969, at the Clermont-Ferrand INRA research station, the French Patrice Leclercq discovered a cytoplasmic male-sterility character by crossing a sunflower with Helianthus petiolaris Nuttall. This was the key event allowing an easy production of F1 hybrid seeds. This character is now used worldwide, and the world crop of sunflower has doubled. It has also come back to North America as a commercial crop, which it was not previously.

Read Targioni-Tozzetti (1853), Gray & Trumbull (1883) and Sturtevant (1919) articles.

• Anderson E., 1956. Man as a maker of new plants and new plant communities. in W.L. Thomas (ed.), Man’s role in changing the face of the earth. Chicago. 763 p.
• Bonjean Alain (éd.), 1986. Tournesols de France. Saint-Jean d'Angély, CST. 189 p.
• Bonjean Alain, 1993. Le tournesol. Paris, Editions de l’Environnement. 242 p.
• Harter Abigail V., Gardner Keith A., Falush Daniel, Lentz David L., Bye Robert A. & Rieseberg Loren H., 2004. Origin of extant domesticated sunflowers in eastern North America. Nature, 430: 201-205.
• Heiser Charles B. Jr., 1976. The sunflower. Norman (Oklahoma), Univ. of Oklahoma Press. 198 p.
• Heiser Charles B. Jr., 1995. Sunflowers. in Smartt J. & Simmonds N.W. (eds), Evolution of crop plants. 2nd ed., pp. 51-53. (including H. tuberosus)
• Heiser Charles B. Jr., 1998. The domesticated sunflower in Mexico ? Genetic Res. Crop Evol., 45 : 447-449.
• Heiser Charles B. Jr., 2008. The sunflower ( Helianthus annuus ) in Mexico: further evidence for a North American domestication. Genetic Res. Crop Evol., 55(1): 9-13.
• Lentz David L., Pohl Mary E.D., Alvarado José L., Tarighat Somayeh & Bye Robert, 2008. Sunflower (Helianthus annuus L.) as a pre-Columbian domesticate in Mexico. Proc. Nat. Acad. Sci. USA, 105(17): 6232-6237.
• Lentz David L., Pohl Mary E.D., Pope Kevin O. & Wyatt Andrew R., 2001. Prehistoric sunflower (Helianthus annuus L.) domestication in Mexico. Econ. Bot., 55(3): 370-376.
• Pappalardo Joe, 2008. Sunflowers: the secret history: the unauthorized biography of the world's most beloved weed. Woodstock, Overlook Press. 256 p.
• Saramandu Nicolae & Uritescu Donin, 1997. Tournesol. Carte de motivations. Commentaire XXXV. in Atlas Linguarum Europae (ALE). Vol. I - Commentaires. Fasc. 5 : 129-139.
• Sauer Jonathan D., 1994. Historical geography of crop plants. A select roster. Boca Raton, CRC Press. 309 p.

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