Análise de trilha da contaminação por aflatoxinas em grãos de milho armazenados

Abstract

Resumo -O objetivo deste trabalho foi determinar a magnitude dos efeitos diretos e indiretos de parâmetros físico-químicos e microbiológicos sobre a ocorrência de aflatoxinas em grãos de milho armazenados, por meio da análise de trilha. Os dados foram coletados em dois experimentos: um cultivo de inverno (colheita do milho em julho de 2012) e um cultivo de verão (colheita em fevereiro de 2013). Os grãos foram armazenados por 12 meses, em dois tipos de acondicionamentos: em sacarias convencionais de polipropileno e a granel em silo metálico. Avaliaram-se 14 características dos grãos. Calculou-se a matriz de correlações de Pearson entre todos os parâmetros, realizou-se o diagnóstico de multicolinearidade e, posteriormente, aplicou-se a análise de trilha com regressão em crista. Observou-se forte influência das condições ambientais entre as safras de inverno e de verão, e entre época e tipo de armazenagem, nos coeficientes de análise de trilha. As variáveis teor de umidade, conteúdo de cinzas, proteínas, lipídios, grãos sem defeitos, massa volumétrica, incidência de Penicillium sp., Aspergillus sp. e Fusarium sp. devem ser consideradas conjuntamente na definição da possibilidade de ocorrência de aflatoxinas na massa de grãos armazenados.Termos para indexação: Zea mays, armazenagem, micotoxinas, multicolinearidade. Path analysis of aflatoxin contamination on stored maize kernelsAbstract -The objective of this work was to determine the magnitude of the direct and indirect effects of the physicochemical and microbiological parameters on the occurrence of aflatoxins on stored maize kernels, through path analysis. Data were collected in two experiments: one winter crop (maize harvest in July 2012) and one summer crop (harvest in February 2013). Grains were stored for 12 months in two types of packaging: in conventional polypropylene sacks and bulk storage in metallic silo. Fourteen grain characteristics were evaluated. The matrix of Pearson's correlations was calculated between all parameters, the diagnosis of multicollinearity was performed, and subsequently path analysis was applied with ridge regression. A strong influence of environmental conditions was observed between winter and summer crops, and between season and type of storage, in path analysis coefficients. The variables moisture content, ash, proteins, lipids, undamaged kernels, volumetric weight, incidence of Penicillium sp., Aspergillus sp., and Fusarium sp. should be considered together for defining the probability of aflatoxin occurrence in the bulk of stored kernels.

Losses Incurred in Soybean Depending on the Water Content at Grains Harvest

“…The results obtained corroborate withMarques et al (2011),Schuh et al (2011) and DiDomenico et al (2015), who predict that the physiological maturity point would be the phenological stage in which the soybean grains present the highest quality and accumulation of dry mass and reduced incidence of pathogens, once in this phenological stage the maximum values were obtained in population of plants and 100 grains mass, however, the reduction of the yield obtained (measured) due to the high water content, is due to the difficulty of threshing of the pods and grains and cleaning, causing them injuries by kneading and losses with retained grains in the pods and plant, corroborating withHoltz & Reis (2013), who report that in the harvest the grains damages, immediate or latent, because the damage can be presented at the time of harvest or in future consequences for the storage and sowing. Both immediate and latent mechanical damage originates at the time of threshing, when considerable forces are applied to the seeds in order to separate them from the pods, mainly because of impacts from the track cylinder.…”

Selecting Corn Agronomic Traits in Breeding high potential Yield: effects of Stem Structure

“…Secondly, adopting correlation analysis [10,11,13,22,23] further clarifies the relation is positive or negative. Finally, utilizing path analysis [2,3,4,5,6,9,12,14] decomposes simple positive and negative correlation coefficient into direct and indirect effects. Thus certain which of the 5 agronomic traits had the biggest direct and indirect influence at positive and negative correlation relationship.…”

Perdas Ocorridas Na Colheita Do Milho Em Função Do Teor De Água Dos Grãos Na Colheita

“…O ponto de maturidade fisiológica é considerado o momento ideal para se realizar a colheita, pois é nesse estádio fenológico que os grãos de milho apresentam a máxima qualidade e acúmulo de massa seca, com reduzida incidência de patógenos (Marques et al, 2011;Schuh et al, 2011;Di Domenico et al, 2015), sem considerar que o atraso na colheita também promove perdas nutricionais e quantitativas dos grãos (Weinberg et al, 2008).…”