TY - JOUR
T1 - A global perspective of the richness and evenness of traditional crop-variety diversity maintained by farming communities
AU - Jarvis, Devra I.
AU - Brown, Anthony H.D.
AU - Pham, Hung Cuong
AU - Collado-Panduro, Luis
AU - Latournerie-Moreno, Luis
AU - Gyawali, Sanjaya
AU - Tanto, Tesema
AU - Sawadogo, Mahamadou
AU - Mar, Istvan
AU - Sadiki, Mohammed
AU - Hue, Nguyen Thi Ngoc
AU - Arias-Reyes, Luis
AU - Balma, Didier
AU - Bajracharya, Jwala
AU - Castillo, Fernando
AU - Rijal, Deepak
AU - Belqadi, Loubna
AU - Rana, Ram
AU - Saidi, Seddik
AU - Ouedraogo, Jeremy
AU - Zangre, Roger
AU - Rhrib, Keltoum
AU - Chavez, Jose Luis
AU - Schoen, Daniel
AU - Sthapit, Bhuwon
AU - De Santis, Paola
AU - Fadda, Carlo
AU - Hodgkin, Toby
PY - 2008/4/8
Y1 - 2008/4/8
N2 - Varietal data from 27 crop species from five continents were drawn together to determine overall trends in crop varietal diversity on farm. Measurements of richness, evenness, and divergence showed that considerable crop genetic diversity continues to be maintained on farm, in the form of traditional crop varieties. Major staples had higher richness and evenness than nonstaples. Variety richness for clonal species was much higher than that of other breeding systems. A close linear relationship between traditional variety richness and evenness (both transformed), empirically derived from data spanning a wide range of crops and countries, was found both at household and community levels. Fitting a neutral "function" to traditional variety diversity relationships, comparable to a species abundance distribution of "neutral ecology," provided a benchmark to assess the standing diversity on farm. In some cases, high dominance occurred, with much of the variety richness held at low frequencies. This suggested that diversity may be maintained as an insurance to meet future environmental changes or social and economic needs. In other cases, a more even frequency distribution of varieties was found, possibly implying that farmers are selecting varieties to service a diversity of current needs and purposes. Divergence estimates, measured as the proportion of community evenness displayed among farmers, underscore the importance of a large number of small farms adopting distinctly diverse varietal strategies as a major force that maintains crop genetic diversity on farm.
AB - Varietal data from 27 crop species from five continents were drawn together to determine overall trends in crop varietal diversity on farm. Measurements of richness, evenness, and divergence showed that considerable crop genetic diversity continues to be maintained on farm, in the form of traditional crop varieties. Major staples had higher richness and evenness than nonstaples. Variety richness for clonal species was much higher than that of other breeding systems. A close linear relationship between traditional variety richness and evenness (both transformed), empirically derived from data spanning a wide range of crops and countries, was found both at household and community levels. Fitting a neutral "function" to traditional variety diversity relationships, comparable to a species abundance distribution of "neutral ecology," provided a benchmark to assess the standing diversity on farm. In some cases, high dominance occurred, with much of the variety richness held at low frequencies. This suggested that diversity may be maintained as an insurance to meet future environmental changes or social and economic needs. In other cases, a more even frequency distribution of varieties was found, possibly implying that farmers are selecting varieties to service a diversity of current needs and purposes. Divergence estimates, measured as the proportion of community evenness displayed among farmers, underscore the importance of a large number of small farms adopting distinctly diverse varietal strategies as a major force that maintains crop genetic diversity on farm.
KW - Conservation on farm
KW - Diversity estimates
KW - Traditional varieties
UR - http://www.scopus.com/inward/record.url?scp=44449097007&partnerID=8YFLogxK
U2 - 10.1073/pnas.0800607105
DO - 10.1073/pnas.0800607105
M3 - Artículo
SN - 0027-8424
VL - 105
SP - 5326
EP - 5331
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 14
ER -