Morphological Characteristics of Safflower Seedlings Under Compaction Levels in a Clayey Latosol

This study aimed to evaluate the effect of soil compaction levels on initial development of safflower genotypes (Carthamus tinctorius). The experimental design was 2 × 2 × 6, composed of two sowing seasons (May and June 2017), two genotypes (IMA-2103 and IMA-4409) and six levels of soil density (1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 g cm-3), with three replicates. After 30 days of planting, percentage of emergence, emergence speed index, mean time of emergence and mean speed of emergence were analyzed. Among the morphological characteristics, plant height, stem diameter, root length, shoot and root fresh mass, shoot dry mass and number of healthy and wilted leaves were evaluated. The compaction states did not significantly interfere in the emergence of the safflower seedlings that were sown in the uncompacted surface layer. As soil compaction increased, root length, shoot fresh mass, shoot dry mass and root fresh mass were reduced in both genotypes. Soil density considered critical to safflower root growth was 1.3 g cm-3. The IMA-4409 genotype, in relation to IMA-2103, was more tolerant to soil compaction levels.