Fluxo gênico em milho sob diferentes tamanhos de amostras e distâncias de amostragem

Abstract

The concern about gene flow between transgenic and conventional maize farming has been received increasing attention in technical and political scope in Brazil. Thus, the objective of this work was to estimate the gene flow in commercial maize farms, as well as the establishment of an adequate sample size to estimate the contamination rate by transgenic in conventional maize fields, using systematic sampling. The samples collections were carried out in fields of grain commercial production in the Itumirim and Madre de Deus municipalities, both in Minas Gerais state, in 2010/2011 crop season and in Ingaí, also Minas Gerais state, in 2011/2012 crop season. Samples were collected at five distances between conventional and transgenic field: 5, 10, 20, 50 and 100 m. Four different sample sizes were also collected: 1, 5, 10 and 15 spikes, with four replications. After collection, a portion of 300 seeds of each sample was used in a real-time PCR for the gene flow estimation. There was no statistical difference among the different sample sizes analyzed at the three sites. In Itumirim and Madre de Deus also no statistical difference was observed among the distances analyzed; the samples collected in Ingaí field in a distance of 10 m had a higher rate of contamination by transgenics when compared to the other samples. The average contamination was below of 1% in all fields.