Relationship between Vegetation Indices and Pinoxaden Toxicity in Two Populations of Avena fatua L.

Objective: To study the relationship between vegetation indices and the toxicity of the herbicide pinoxaden on two populations of Avena fatua L. Design/methodology/approach: A completely randomized design with a 2x4 factorial arrangement was used in the laboratory, with factor A being the two populations of Avena fatua and factor B being the four concentrations of the pinoxaden herbicide (0, 30, 60 and 120 g a.i. ha-1). The percentage of control, plant height and the GA and GGA vegetation indices were evaluated. The data were analyzed with an ANOVA and a comparison of means was performed with the Tukey test (α=0.05). The relationship between the control percentage and vegetation indices was determined by Pearson correlation analysis. Results: There was a higher percentage of control, plant height, GA index and GGA index in the Avena fatua population from alfalfa compared to the wheat population, indicating that pinoxaden has greater phytotoxicity for the alfalfa population. A negative correlation was observed between the control percentage and the GA index for the two populations regardless of the evaluation time, a similar negative correlation was found for the GGA index in both populations. This indicates that the GA and GGA indices decrease as the control percentage increases. Findings/conclusions: The GA and GGA indices were inversely correlated with the control percentage of the herbicide pinoxaden. The GA and GGA indices obtained through digital camera images are feasible to estimate the toxicity levels of the herbicide pinoxaden.