Classification of Crop Tolerance to Heat and Drought: A Deep Convolutional Neural Networks Approach
Environmental stresses such as drought, and heat can cause substantial yield loss in corn hybrids. As such, corn hybrids which are tolerant to drought, and heat would produce more consistent yields compared to the hybrids which are not tolerant to these stresses. In the 2019 Syngenta Crop Challenge, Syngenta released several large datasets that recorded the yield performances of 2,452 maize hybrids planted in 1,560 locations between 2008 and 2017 and asked participants to classify the corn hybrids as either tolerant or susceptible to heat stress, drought stress, and stress due to the combination of heat and drought. As one of the winning teams, we designed a two-step approach to solve this problem in an unsupervised way since no dataset was provided that classified any set of hybrids as tolerant or susceptible to any stress. First, we designed a deep convolutional neural network (CNN) that took advantage of state-of-the-art modeling and solution techniques to extract stress metrics for each types of stress. Our CNN model was found to successfully distinguish between the low and high stress environments due to considering multiple factors such as plant/harvest dates, daily weather, and soil conditions. Then, we conducted a linear regression of the yield of hybrids against each stress metric, and classified the hybrids based on the slope the regression line, since the slope of the regression line showed how sensitive a hybrid was to a specific environmental stress. Our results suggested that only 14 were tolerant to at least one type of stress.
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