Distribution of Diplodia maydis e Diplodia macrospora in the main areas producing of corn seeds in Brazil. / Distribuição de Diplodia maydis e Diplodia macrospora nas principais regiões produtoras de sementes de milho no Brasil.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

In fields of production of seeds from the South, Southeast and Center-west regions of Brazil it was determined the frequency and incidence of fungus associated to the corn seed in 68 samples of seeds of hybrid corn, cultivated in the normal harvest and 24 samples of seeds of hybrid corn, cultivated in the second harvest in 2001/2002 season. The incidence and total frequency of fungus was determined in samples of corn seed, collected after process of manual selection of ears corn with symptoms of ear rot. The incidence and the frequency of D. maydis and D. macrospora was determined in samples of corn seeds reject, constituted of ears of corn with symptoms of ear rot, collected during the process of manual selection of ears of corn accomplished in the Unit of Improvement of Seeds. In the normal harvest, the data were analyzed according to analysis of Cluster through the similarity of the behavior of the hybrid. It was detected three groups of hybrid distributed in three different altitude levels, being Fusarium spp. the fungus with more frequency and incidence, in the sample seed, for three groups. The analysis of the sample reject presented larger incidence of D. macrospora, for the three groups of altitudes, being the largest incidence observed at the Center-west region, in altitudes of 800-1200 msnm., while D. maydis presented the largest incidence in the South region, in altitudes of 350-600 msnm. In the second harvest, it was observed lowers total incidence of fungus, being the largest incidence of Fusarium spp.

ASSUNTO(S)

diplodia maydis agronomia milho fungos diplodia macrospora sementes

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