Evaluation of Germination and Seedling Root Parameters in Local Maize Landraces Under Drought Stress

Drought is regarded as the most significant environmental factor affecting the productivity of maize (Zea mays L.) worldwide. The integration of maize landraces, conserved in germplasm bank collections, into elite breeding programs could increase the resilience of modern hybrids to drought and mitigate the genetic erosion identified within the genetic base of cultivated maize. In this study, seeds of fifteen Croatian maize landraces were exposed to four levels of drought stress induced by polyethylene glycol (PEG) to evaluate the effect of drought on their seed germination and seedling root parameters. Analysis of variance revealed significant differences among landraces (G) and applied drought stress treatments (PEG) for all traits, as well as a significant PEG × G interaction for all traits except germination potential. The application of the highest drought stress level, caused by a 20% PEG water solution, reduced germination percentage by 51%, germination potential by 99%, root length by 87%, root diameter by 26%, root area by 91% and root volume by 93% compared to the control. Three landraces, MAK7, MAK11 and MAK15, showing high germination potential, long roots and large root area and volume under drought conditions, were identified as pre-breeding candidates for possible reintroduction into modern breeding programs aimed at increasing drought tolerance. The applied method of PEG-induced drought effectively identified drought-tolerant landraces and can be used for rapid screening of drought tolerance in large numbers of genebank accessions conserved in genebanks.