Resumo

RUIZ CORRAL, José Ariel et al. Mexican maize races as a germplasm source for adpatation to climate change. Rev. Mex. Cienc. Agríc [online]. 2011, vol.2, n.spe2, pp.365-379. ISSN 2007-0934.

The maize production in Mexico facing the climatic change phenomenon is a complex problem that needs to be comprehensively addressed due to the very difficult social problems that it may generate. The aim of this paper was to characterize and to identify the environmental adaptability associated with high temperature and low moisture availability conditions from 48 Mexican maize races. The study was conducted in 23 586 accessions of 48 Mexican maize races; using geographical coordinates, the average major agro-climatic conditions were characterized, in which are currently developing maize races. In this characterization the following parameters were considered: precipitation (P), potential evapotranspiration (PET), humidity index (HI)= P/PET, mean maximum temperature (Txm), mean minimum temperature (Tim), average temperature (Tm), thermal oscillation (OT)= Txm-Tim and, number of days with temperature >35 °C (NDT35). All but the latter one, of these parameters were managed at annual, seasonal (May-October) and monthly (August and September), producing a total of 36 variables of agroclimatic characterization of the accession sites. With the environmental averaging by race, an analysis of numerical taxonomy was performed; through a cluster with the option of product-moment correlation between races. Using this analysis, four racial groups were identified, one of them brought together races with adaptation to high temperatures and moisture deficits during the cycle from May to October and, concluding that, it's in this racial group where exists the greatest probability of finding genes that may contribute to developed maize genotypes with resistance to high temperatures and, water deficit.

Palavras-chave : Zea mays L.; genetic diversity; environmental factors.

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