Comportamento de híbridos de milho em sucessão a soja, ao nematoide Pratylenchus brachyurus

Abstract

Due to economical damage caused by nematodes in soy bean crop, arises the necessity of identification of maize hybrids which present resistance and reduce the population of this pathogen in successive cultivations of soy bean. This work aimed at evaluating the reaction of maize hybrids to the nematode Pratylenchus brachyuru, responsible for root lesions, in different locations in the State of Mato Grosso. Two experiments were installed in the 2010/2011 agricultural year. The first, in March 13th 2011, in the municipality of Tapurah, and the second, in March 14th 2011, in the municipality of Sorriso, both under no-tillage system. Ten maize hybrids were sown in succession to soy bean, in areas with the root lesions nematode infestation symptoms. A completely randomized block design with three replicates in a time subdivided parcel scheme was used. The number of nematodes per gram of root and the reproductive capability (RC) at 50 and 90 days after sowing were evaluated. The results allowed the identification of maize hybrids tolerant to the analyzed nematode. The hybrids which demonstrated smaller populations per gram of root and smaller reproductive capacity for the nematode Pratylenchus brachyurus must be preferred for sowing in infested areas.