Dinâmica de fitonematoides, respostas nutricionais e enzimáticas da cana-de-açúcar

Abstract

Brazil is the largest producer of sugar cane, however, the northeast region has low productivity, when compared to the center-south of the country. This low productivity is related to several factors, abiotic and biotic, among them the ones caused by plant parasitic nematodes. To know the effects of the management attributed to sugarcane in the conditions of the Northern Pernambuco Forest on the dynamics of populations of phytonematoids, in particular Meloidogyne sp. and Pratylenchus sp., soil chemical attributes, enzymatic and biometric responses of the plant are fundamental for understanding the variations in the activity of the population of these organisms and consequent effects on agricultural productivity. The objectives of this study were: 1) to observe seasonal changes and evaluate the relationship between nematode communities and parameters of plants in sugarcane; 2) evaluate the seasonal changes and the relationship between fitonematides Meloidogyne and Pratylenchus, the growth parameters of the plant and changes in the levels of antioxidant enzymes SOD and APX in different densities of plant parasitic nematodes in sugarcane under field conditions; 3) evaluate relations between the spatial-temporal distribution of endoparasites nematodes Meloidogyne and Pratylenchus and biometric attributes, nutritional and enzymatic of sugarcane (cane plant and ratoon cane). The study was conducted in two areas cultivated with sugarcane in dryland management located at the Olho D'água Plant, in the municipality of Camutanga, Pernambuco / Brazil. The results indicated that abundance of Meloidogyne and Pratylenchus, plant nutrients and growth parameters in sugarcane plantations respond differently to environmental variation. In general, populations of Meloidogyne and Pratylenchus were positively associated with growth parameters of sugarcane, suggesting that the varieties planted in both areas were tolerant to these nematodes. The results also suggest that sugar cane infection by Pratylenchus and Meloidogyne is associated with an increase in the activity of the SOD enzyme, with a protective role to reduce oxidative damage in sugarcane. In area 1, the spatial-temporal distribution patterns of Meloidogyne sp. and Pratylenchus sp. differed according to the time of sampling, becoming in general more homogeneous over time; The development of sugarcane in area 2 was affected by regions of high population density of Pratylenchus sp., which coincided with regions with low levels of K and Mg.