Physiological response of cotton seeds treated with thiamethoxam under heat stress

This study aimed to verify the effect of seeds treated with thiamethoxam on the emergence, growth and chlorophyll content of seedlings of two cotton cultivars subjected to abiotic stress. The seeds used were from the DeltaOpal and NuOpal cultivars, each one represented by three lots, previously subjected to determination of moisture content, germination and vigor (low temperature germination). Then, the seeds from each lot, treated with thiamethoxam at a dose of 600 mL of product per 100 kg-1 seed or not, were exposed to temperature (18, 25 and 35 °C) and water availability (40, 60 and 80%) stress conditions. The emergence percentage, the root and shoot length, and the chlorophyll content were evaluated. The growth of cotton seedlings from the DeltaOpal and NuOpal cultivars, subjected to low temperature conditions and water availability of 40 to 60%, is favored by seed treatment with thiamethoxam. Seed treatment with thiamethoxam increases chlorophyll content during the development of cotton plants.