Effects of Water Osmotic Potentials and Soil Moisture on Seed Germination and Seedling Emergence of Wild Mustard (Sinapis arvensis) Ecotypes

  In this study the effects of osmotic potential of water and drought stress on seed germination and seedling emergence of wild mustard (Sinapis arvensis) ecotypes were studied. The seeds were collected from four provinces including Fars, West Azarbaijan, Khoozestan and Mazandaran. Trials were carried out to study the effects of osmotic potential of PEG-6000 solutions at seven levels (0, -0.01, -0.05, -0.25, -0.1, -0.5, -1.5 MPa) on seed germination of four populations of wild mustard. In addition, the seedling emergence pattern of the populations was investigated in response to three soil moisture regimes (field capacity (FC),FC–1/3FC–FC, FC–1/6FC–FC) on percent weed emergence in a greenhouse. Results showed the highest germination occurred at 0 MPa osmotic potential. Germination gradually decreased by reducing the osmotic potential to -1.5 MPa. The trend was different among the ecotypes. The most number of germinated seeds was observed at high soil moisture (field capacity). The seeds of all ecotypes were sensitive to drought stress. Seed undr drough stress transformed to secondary dormancy and hence returning to field capacity did not induce germination.