摘要：In order to study the effect of drought stress on germination indices in sesame ( Sesamum indicum L.), a factorial experiment, using a completely randomized design with three replications was conducted. In this experiment, 22 confirmed sesame mutants induced through gamma ray treatment and their respective three parental sources were evaluated for five levels of drought stress (ψs= 0, -0.5, -1, -1.5 and -2 MPa) using aqueous solutions of PEG-6000. For each treatment, germination was checked every 48 h. Emerged seedling percentages as well as seedling root length were recorded after 7 days of experiment. Results evidence significant differences among genotypes and drought stress levels. Germination, emergence and root length were significantly reduced against control from a drought stress level ≤-1 MPa. Seeds did not germinate at all at an osmotic potential ≤-1.5 MPa whereas emergence was completely inhibited by -1 MPa. In present experimental conditions, a mild drought stress (-0.5 MPa) improved root growth in most genotypes studied as compared to controls. Emergence was the parameter the most affected by drought stress and germination the least affected. Genotypes hsc105, lc162, mc112, ef147 and hc107 were found to be more drought tolerant than their respective parents. Although sesame is reputed to be a drought tolerant crop, it is very susceptible to drought at germination stage and sufficient soil moisture is required for sesame seed emergence.
