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Hellin, J.

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Hellin
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Hellin, J.
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0000-0002-2686-8065

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Now showing 1 - 3 of 3
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    Adapting maize production to climate change in sub-Saharan Africa
    (Springer Verlag, 2013) Cairns, J.E.; Hellin, J.; Sonder, K.; Araus, J.L.; MacRobert, J.; Thierfelder, C.; Prasanna, B.M.
    Given the accumulating evidence of climate change in sub-Saharan Africa, there is an urgent need to develop more climate resilient maize systems. Adaptation strategies to climate change in maize systems in sub-Saharan Africa are likely to include improved germplasm with tolerance to drought and heat stress and improved management practices. Adapting maize systems to future climates requires the ability to accurately predict future climate scenarios in order to determine agricultural responses to climate change and set priorities for adaptation strategies. Here we review the projected climate change scenarios for Africa?s maize growing regions using the outputs of 19 global climate models. By 2050, air temperatures are expected to increase throughout maize mega- environments within sub-Saharan Africa by an average of 2.1°C. Rainfall changes during the maize growing season varied with location. Given the time lag between the development of improved cultivars until the seed is in the hands of farmers and adoption of new management practices, there is an urgent need to prioritise research strategies on climate change resilient germplasm development to offset the predicted yield declines.
    Publication
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    Manejo de semillas y diversidad del maiz
    (Asociación Ecología,Tecnología y Cultura en los Andes, 2007) Hellin, J.; Bellon, M.
    México es el centro del origen y diversidad del maíz. Según la evidencia arqueológica, su cultivo en Mesoamérica es de aproximadamente 6.000 años, pero los datos genéticos indican cerca de 9.000. Entre la población nativa la planta de maíz representa el origen mismo de la vida. Principalmente se utilizan dos de sus tipos: maíz de grano blanco para el consumo humano directo y maíz de grano amarillo para el consumo indirecto como uno de los componentes de la alimentación del ganado y animales menores, la mayor parte en la producción de aves de corral, huevos y carne de cerdo. Los usos secundarios incluyen: los tallos de maíz como cercos, las hojas de la planta como forraje y las hojas o pancas que cubren la mazorca del maíz para envolver alimentos tradicionales, como los tamales. Las prácticas tradicionales de manejo de las semillas de maíz incluyen la utilización de semillas guardadas de la última cosecha u obtenidas de familiares o amigos. Esto contribuye a introducir nueva diversidad genética al sistema, proporcionando de esta manera rasgos que los agricultores consideran importantes, por ejemplo, rendimiento, facilidad de manejo y sabor. Muchos agricultores mantienen diversas variedades locales de maíz dentro de un mismo sistema de cultivo. Esta es una manera de lidiar con el estrés y los altos riesgos que implica la producción agrícola en ambientes marginales.
    Publication
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    Estimating maize genetic erosion in modernized smallholder agriculture
    (Springer, 2009) Heerwaarden, J. van; Hellin, J.; Visser, R.G.F.; Eeuwijk, F. van
    Replacement of crop landraces by modern varieties is thought to cause diversity loss. We studied genetic erosion in maize within a model system; modernized smallholder agriculture in southern Mexico. The local seed supply was described through interviews and in situ seed collection. In spite of the dominance of commercial seed, the informal seed system was found to persist. True landraces were rare and most informal seed was derived from modern varieties (creolized). Seed lots were characterized for agronomical traits and molecular markers. We avoided the problem of non-consistent nomenclature by taking individual seed lots as the basis for diversity inference. We defined diversity as the weighted average distance between seed lots. Diversity was calculated for subsets of the seed supply to assess the impact of replacing traditional landraces with any of these subsets. Results were different for molecular markers, ear- and vegetative/flowering traits. Nonetheless, creolized varieties showed lowdiversity for all traits. These varieties were distinct from traditional landraces and little differentiated from their ancestral stocks. Although adoption of creolized maize into the informal seed system has lowered diversity as compared to traditional landraces, genetic erosion was moderated by the distinct features offered by modern varieties.
    Publication