A minor role for environmental adaptation in local–scale maize landrace distribution : results from a common garden experiment in Oaxaca, Mexico

Periodo de realización: 1900/01/01 al 2014/06/01

Tipo: Artículo científico

Resumen: "Agronomists usually assume that yieldis a primary selection trait for farmers practicing traditional agriculture. They hypothesize that thelandraces grown in farmers’ fields produce higher yields than other local landraces would, ifgrown in the same fields.We test this hypothesis in experimental gardens using maize landracesgrown by indigenous farmers in a low– to mid–elevation region in Oaxaca, Mexico.We selectedfour villages, two Chatino and twoMixtec, two in low and two in middle elevations.We plantedreciprocal common gardens in each village, in order to test whether or not local maize landraceswere higher yielding in their respective villages—a finding that would suggest they are selectedbecause they are better adapted to local conditions than landraces from other villages. We alsotested resistance to a fungal disease (ear rot caused by Fusarium) that is cited by farmers in theregion as a major problem for maize production. We found that maize samples planted in theirvillages of origin did not in general have higher yields than samples from other villages. There aresignificant interactions among common garden site, fertilizer use, and seed source.We found thatlandraces fromthe Chatino lowlands village performwell in most sites, with andwithout fertilizer.Regarding ear rot, there is some evidence that landraces are less susceptible when grown awayfrom their villages of origin. These results suggest that social factors, such as seed networks andethno–linguistic membership, may be more important than local environmental adaptation indetermining the distribution of landraces in this region."

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