Could raking over the ashes of past civilisations help tackle the current food crisis? at the University of Cincinnati, Ohio, thinks so.
Genetic information from wild strains of domestic crops could help to improve crop yield, he says, making it important to identify the point of domestication.
That makes his controversial theory that the sunflower was domesticated in Mexico at least 4000 years ago more than just a matter of ancient history.
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鈥淚f we are to improve the sunflower crop, we need to look at its full genetic base,鈥� Lentz says. 鈥淏ut conventional wisdom is that sunflowers were cultivated in eastern North America, and so Mexico has been ignored.鈥�
Although the crop is now present in Mexico, the traditional view is that the Spanish Conquistadors introduced it to the area from the north in the 16th century.
Rare find
Lentz challenged that view in 2001. His team unearthed a 4100-year-old achene, or fruit, at San Andr茅s in Mexico. , a world authority on sunflowers, identified the achene as belonging to the domesticated sunflower. This raised the intriguing possibility that the sunflower was first domesticated in Mexico.
But critics argued that the single sunflower achene was no more than an anomaly. 鈥淧eople have been taking pot shots at me for a long time because the San Andr茅s achene was an isolated find,鈥� Lentz says.
Now, his team has dug deeper into Mexican culture to show that the sunflower has an ancient history in the area.
If the sunflower was a foreign introduction by the Spanish, Lentz argues that it should be known by the Spanish name for 鈥渟unflower鈥� across Mexico 鈥� in much the same way that Japanese sushi carries a similar name across Europe. Instead, his team found that 11 of 14 indigenous Mexican groups each had a unique name for the plant.
鈥楾enuous evidence鈥�
Crucially, Lentz鈥� team also reports the discovery of three more Mexican sunflower achenes, this time from Cueva del Gallo in Morelos, which date to around 300 BC. 鈥淲ith this additional evidence, my view 鈥� and that of my co-authors 鈥� is that the evidence [of Mexican domestication] is so strong as to be almost irrefutable,鈥� says Lentz.
Not so, according to at the Smithsonian National Museum of Natural History, Washington, DC. 鈥淭he archaeological evidence is extremely tenuous to the point of being non-existent,鈥� he says.
He points out that, even with the new finds, the Mexican archaeological record contains barely a handful of sunflower seeds. 鈥淭o provide some context, more than 3000 sunflower seeds, achenes, and discs have been recovered from sites in eastern North America,鈥� Smith says.
Smith is not even convinced that the Mexican seeds found belong to the sunflower. Earlier this year, Heiser changed his mind about the San Andr茅s achene 鈥� he now says its morphology is suggestive of a bottle gourd, and he is sceptical that the sunflower was domesticated in Mexico.
Lentz points out that the new seeds, from Cueva del Gallo, are so well preserved that their identification is beyond question. 鈥淚 don鈥檛 see how any objective viewpoint can maintain that the sunflower was not a pre-Columbian domesticate in Mesoamerica,鈥� he says.
Descriptive clues
, a linguistic anthropologist at Northern Illinois University in DeKalb, says that borrowing the Spanish word for sunflower would be just one strategy open to indigenous Mexicans encountering the sunflower for the first time in the 16th century.
鈥淧robably just as common is to make up a descriptive name for that new thing,鈥� he says. All of the 11 unique names for 鈥渟unflower鈥� listed by Lentz鈥檚 team, including 鈥渂ig sun鈥� or 鈥渟hield flower鈥�, are descriptive. This is consistent, he says, with the idea that the crop was introduced by the Spanish.
鈥淭he linguistic evidence actually indicates rather robustly that [the sunflower] was introduced from outside the area,鈥� Brown says.
However, Lentz thinks that most of the hostility against his work is due to a misunderstanding. He suggests domestication did not occur just once, either in Mexico or in eastern North America.
鈥淭his is not all or nothing. Sunflower was an easy crop to domesticate鈥� Lentz says. 鈥淭he fact that we find domesticated sunflower in pre-Columbian Mexico doesn鈥檛 preclude a second domestication event in eastern North America.鈥�
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