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An improved simulation model to predict pre-harvest aflatoxin risk in maize

Chauhan, Yashvir and Tatnell, Jeff and Krosch, Stephen and Karanja, James and Gnonlonfin, Benoit and Wanjuki, Immaculate and Wainaina, James and Harvey, Jagger (2015) An improved simulation model to predict pre-harvest aflatoxin risk in maize. Field Crops Research, 178 . pp. 91-99. ISSN 0378-4290

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Article Link(s): http://dx.doi.org/10.1016/j.fcr.2015.03.024

Publisher URL: http://www.sciencedirect.com/science/article/pii/S037842901500115X

Abstract

Aflatoxin is a potent carcinogen produced by Aspergillus flavus, which frequently contaminates maize (Zea mays L.) in the field between 40° north and 40° south latitudes. A mechanistic model to predict risk of pre-harvest contamination could assist in management of this very harmful mycotoxin. In this study we describe an aflatoxin risk prediction model which is integrated with the Agricultural Production Systems Simulator (APSIM) modelling framework. The model computes a temperature function for A. flavus growth and aflatoxin production using a set of three cardinal temperatures determined in the laboratory using culture medium and intact grains. These cardinal temperatures were 11.5 °C as base, 32.5 °C as optimum and 42.5 °C as maximum. The model used a low (≤0.2) crop water supply to demand ratio—an index of drought during the grain filling stage to simulate maize crop's susceptibility to A. flavus growth and aflatoxin production. When this low threshold of the index was reached the model converted the temperature function into an aflatoxin risk index (ARI) to represent the risk of aflatoxin contamination. The model was applied to simulate ARI for two commercial maize hybrids, H513 and H614D, grown in five multi-location field trials in Kenya using site specific agronomy, weather and soil parameters. The observed mean aflatoxin contamination in these trials varied from <1 to 7143 ppb. ARI simulated by the model explained 99% of the variation (p ≤ 0.001) in a linear relationship with the mean observed aflatoxin contamination. The strong relationship between ARI and aflatoxin contamination suggests that the model could be applied to map risk prone areas and to monitor in-season risk for genotypes and soils parameterized for APSIM.

Item Type:Article
Business groups:Crop and Food Science
Keywords:APSIM Aspergillus flavus Drought Mycotoxin Temperature Zea mays L.
Subjects:Science > Statistics > Simulation modelling
Plant culture > Field crops > Corn. Maize
Plant pests and diseases > Plant pathology
Deposited On:09 Feb 2016 00:51
Last Modified:15 Feb 2016 23:03

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