Geographical variation in seed germination of Hemp (Cannabis sativa L.) ecotypes under salinity conditions

Abstract

Seed germination is a critical phase during the life cycle of plants, which is strongly influenced by environmental and genetic properties such as salinity and ecotype. Accordingly, in this laboratory experiment the germination and seedling growth response of ten hemp ecotypes, collected from ten different regions of Iran, was studied to salinity stress levels (0, 68, 136, 203, 271, 339, 407, and 474 mM NaCl, correspond to a water potential of 0, − 0.3, − 0.6, − 0.9, − 1.2, − 1.5, − 1.8, and − 2.1 MPa, respectively), using a factorial experiment based on a completely randomized design. Seed germination characteristics encompass the first (FDG) and the last day of germination (LDG), which were recorded. Subsequently, the germination period (GP), final germination percentage (FGP), germination rate (GR), and germination index (GI) were computed. Root and shoot length (RL and SL), root and shoot fresh and dry weight, and seedling dry weight (RFW, RDW, SFW, SDW, and SeDW) were quantified, and the allometric coefficient (AC) and seedling vigor (SVI) were computed. All ten ecotypes of hemp had high FGP under control conditions (0 MPa). Salinity levels led to a decrease in FGP, GI, GR, RL, SL, RFW, RDW, SFW, SDW, SeDW, and SVI in compared to control, in all ecotypes. Hamedan, Tehran, and Darmian ecotypes exhibited the greatest salinity tolerance, whilst the Zahedan, Bushehr, and Kerman ecotypes displayed the lowest resistance to salinity, as determined by seed germination and seedling growth characteristics. Salinitytolerant ecotypes were identified in different geographical areas, indicating that the salinity tolerance of hemp is contingent upon genetic variation.