Correlação entre fitonematoides e produtividade de soja em lavouras de alto e baixo rendimento

Abstract

Soy is one of the most economically important crops. However, in the last two decades, the average yield has shown less progress compared to the evolution of the planted area. Thus, the Strategic Committee of Soja Brasil (CESB) seeks to encourage the development of innovative cultivation practices, which enable the extraction of the maximum potential of the crop. However, the decrease in soybean yield is subject to different factors. Among these, nematodes are one of the microorganisms that cause the most damage. The aim of this study was to correlate the effects of phytonematodes on soybean production in low and high yield crops at CESB. Samples were collected from 63 low and high yield soybean crops in the State of Mato Grosso. These were then sent for processing at the Nematology Laboratory of the Federal University of Mato Grosso, in the municipality of Barra do Garças. The flotation-centrifugation methodology (Jenkins, 1964) and the extraction of nematodes from plant tissues by grinding, followed by flotation and centrifugation (Coolen & D’herde, 1972) were adopted to extract nematodes from the soil and roots, respectively. The population estimate was performed by means of Peters slide counting, using an optical microscope. The nematological and soybean productivity data were analyzed with the aid of the statistical program MINITAb 14. An analysis of the correlation between productivity and nematological variables was made, and Pearson's coefficient was selected when significant at 5% probability. Thus, it is concluded that high populations of Pratylenchus brachyurus and Heterodera glycines are correlated with high productivity values in high-yield soybean crops; and larger populations of P. brachyurus are correlated with low productivity values in low-yield soybean crops.