Forage Kochia Germination Response to Temperature, Water Stress, and Specific Ions1

Forage kochia [Kochia prostrata (L.) Schrad.] may be useful for revegetating salt affected soils. This study was designed to quantify the effects of temperature, water stress, and specific ions on the germination of ‘Immigrant’ forage kochia. Fruits and seeds were germinated at 10, 20 and 30°C in solutions of polyethylene glycol (PEG) with osmotic potentials ranging from −0.52 to −2.32 MPa. Seeds were also germinated at 20°C in PEG solutions containing 0 to 53 640 µmol L−1 potassium chloride (KCl‐PEG) and 0 to 68 480 µmol L−1 sodium chloride (NaCl‐PEG) with osmotic potentials ranging from −0.3 to −2.2 MPa. Germination was reduced by declining osmotic potentials. Total germination was highest at 20°C and lower at 10 and 30°C. Germination in NaCl‐PEG and KCl‐PEG solutions was primarily reduced by low osmotic potentials; percent germination was not affected by increasing NaCl concentrations but was reduced by increasing KCl concentrations. Number of days to 50% final germination was similar in both salts, increasing as osmotic potential declined and salt concentration increased. Forage kochia appears moderately tolerant of NaCl and KCl during germination and growth and may be well suited for revegetating salt affected soils in the Intermountain Region. Fruits are recommended for planting because abnormal germination was less than with seeds. Forage kochia should be sown prior to periods when soil temperatures are in the 10 to 20°C range, and cultural practices that extend the period of high soil osmotic potentials should be used to maximize seed germination.