Qualidade fisiológica de sementes de populações de milho crioulo da zona da mata de Minas Gerais

Abstract

O objetivo deste trabalho foi avaliar a qualidade fisiológica das sementes de populaçOes locals de "milho de paiol" coletadas em propriedades agricolas na regiao de Viçosa, na Zona da Mata de Minas Gerais, em 2001. Doze popu1açes locals de poliniza0o aberta de milho, nomeadas corn a inicial B, foram avaliadas quarto a qualidade fisiológica das sementes. 0 delineamento experimental foi o inteiramente casualizado nos experimentos de laboratóno. Os testes-padrao de germinação (TPG), primeira contagem e envelhecimento acelerado foram conduzidos corn quatro repedOes de 50 sementes. Foram realizados doffs testes de envelhecimento acelerado, urn corn fungicida e outro sem. Ds resultados da germinação, avaliados pelo TPG, mostraram que somente tits cultivates foram inferiores aos demais, e destes somente doffs apresentaram valores abaixo de 85%, limite minimo para lote corn qualidade comercial. 0 vigor das sementes, avaliado pela primeira contagem, mostrou que somente as populaOes B 20, B 19 e B 17 foram superiores s populaoes B 21, B 25 e B 10, as demais apresentaram valores i ntermedi an o s . 0 teste de envelhecimento acelerado revelou valores medios de 62 a 91% nas sementes nao-tratadas e de 76 a 99% nas tratadas. Nas populaçöes locals B 9, B 11, B 17, B 18 e B 21 o fungicida contribuiu pars inibir o desenvolvimento de microrganismos. Conclui-se que as populaçöes locals de milho apresentam alts qualidade fisiológica de sementes, nAo sendo causa dosbaixos estandes das lavouras na região, e os microrganismos são devidos ao armazenamento inadequado, que pode diminuir a qualidade das sementes.The objective of this work was to evaluate the physiological quality of local maize seeds collected on farms in Viçosa region, Zona da Mata, Minas Gerais, Brazil, in 2001. Twelve open-pollinated local varieties were evaluated as to their physiological quality. The experimental design was completely randomized. The standard germination test (SGT), first counting and accelerated aging test were carried out with four replications of 50 seeds. Two accelerated aging test were conducted, one with fungicide and the other without fungicide. The germination results, evaluate by SGT, showed that only three cultivars were inferior to the rest, with only two showing values below 85%, the minimum commercial value limit. Seed vigor, evaluated by first counting, showed that only the populations B 20, B 19 and B 17 were superior to populations B 21, B 25 and BIO, with the rest showing intermediary- values. The accelerated aging test showed mean values ranging from 62 to 91% for the non-treated seeds and from 76 to 99% for the treated seeds. For the populations B 9, B 11, B 17, B 18 and B 21, fungicide application inhibited microorganisms develºpment. It was concluded that local maize populations have high physiological quality seeds, thus not being the cause for the low stands in the region, and that the presence of microorganisms is due to inadequate storage, which can decrease seed quality.