Variability of Root and Shoot Traits Under PEG-Induced Drought Stress at an Early Vegetative Growth Stage of Maize

Development of maize varieties with enhanced tolerance to drought stress has become a high-priority goal for maize breeding programs worldwide. In order to assess the variability of root and shoot traits in response to drought at an early vegetative stage, a set of 32 maize single-cross hybrids available on the Croatian market was grown under polyethylene glycol 8000 induced drought stress and well-watered control treatments. The induced drought stress negatively affected the growth and development of the maize seedlings. Significant differences among the hybrids, water treatments, and their interaction were found for the four directly measured traits (root and shoot length, and root and shoot fresh weights), as well as for the majority of four derived traits (root and shoot dry matter content, root-to-shoot length ratio, and root fresh weight to shoot fresh weight ratio). In the studied set of hybrids, heritabilities for the four directly measured traits were generally high, and the correlations among traits were strong under both water treatments, indicating their suitability for assessment of drought tolerance at the seedling stage.