Convergent Adaptations: Bitter Manioc Cultivation Systems in Fertile Anthropogenic Dark Earths and Floodplain Soils in Central Amazonia


Autoria(s): Fraser, James Angus; Alves-Pereira, Alessandro; Junqueira, Andre Braga; Peroni, Nivaldo; Clement, Charles Roland
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

25/09/2013

25/09/2013

2012

Resumo

Shifting cultivation in the humid tropics is incredibly diverse, yet research tends to focus on one type: long-fallow shifting cultivation. While it is a typical adaptation to the highly-weathered nutrient-poor soils of the Amazonian terra firme, fertile environments in the region offer opportunities for agricultural intensification. We hypothesized that Amazonian people have developed divergent bitter manioc cultivation systems as adaptations to the properties of different soils. We compared bitter manioc cultivation in two nutrient-rich and two nutrient-poor soils, along the middle Madeira River in Central Amazonia. We interviewed 249 farmers in 6 localities, sampled their manioc fields, and carried out genetic analysis of bitter manioc landraces. While cultivation in the two richer soils at different localities was characterized by fast-maturing, low-starch manioc landraces, with shorter cropping periods and shorter fallows, the predominant manioc landraces in these soils were generally not genetically similar. Rather, predominant landraces in each of these two fertile soils have emerged from separate selective trajectories which produced landraces that converged for fast-maturing low-starch traits adapted to intensified swidden systems in fertile soils. This contrasts with the more extensive cultivation systems found in the two poorer soils at different localities, characterized by the prevalence of slow-maturing high-starch landraces, longer cropping periods and longer fallows, typical of previous studies. Farmers plant different assemblages of bitter manioc landraces in different soils and the most popular landraces were shown to exhibit significantly different yields when planted in different soils. Farmers have selected different sets of landraces with different perceived agronomic characteristics, along with different fallow lengths, as adaptations to the specific properties of each agroecological micro-environment. These findings open up new avenues for research and debate concerning the origins, evolution, history and contemporary cultivation of bitter manioc in Amazonia and beyond.

Leverhulme Trust

Leverhulme Trust [F/00 230/W]

CNPq (Brazilian National Research Council) (CT Amazonia) [575588/08-0]

CNPq (Brazilian National Research Council) (CT Amazonia)

Identificador

PLOS ONE, SAN FRANCISCO, v. 7, n. 8, supl. 4, Part 1-2, pp. 491-500, AUG 29, 2012

1932-6203

http://www.producao.usp.br/handle/BDPI/33720

10.1371/journal.pone.0043636

http://dx.doi.org/10.1371/journal.pone.0043636

Idioma(s)

eng

Publicador

PUBLIC LIBRARY SCIENCE

SAN FRANCISCO

Relação

PLOS ONE

Direitos

openAccess

Copyright PUBLIC LIBRARY SCIENCE

Palavras-Chave #MANIHOT-ESCULENTA CRANTZ #GENETIC DIVERSITY #TRADITIONAL AGROECOSYSTEMS #CASSAVA #MANAGEMENT #DYNAMICS #ECOLOGY #BRAZIL #SEED #MICROSATELLITES #MULTIDISCIPLINARY SCIENCES
Tipo

article

original article

publishedVersion