Germination at low osmotic potential as a selection criteria for drought stress tolerance in sweet corn

Water stress can affect germination by decreasing the percentage of germination. A study was undertaken to evaluate the influence of different osmotic potentials (MPa) on proline content and percentage seed germination of corn. The experiment was conducted in factorial with a randomized complete block design (RCBD) with three replications. Seeds of two open pollinated varieties (Masmadu and Thai super sweet) and three hybrids (968, 969 and 926) sweet corn were germinated at 0, -0.2, -0.5, -0.7, -1.2 and -1.4 MPa osmotic potentials, respectively. Results show that the percentage of germination and coefficient of velocity (CVG) decreased with decrease in osmotic potential while proline content and mean germination time (MGT) increased. Polyethylene glycol (PEG) increased root length (RL) and length per volume (LPV) at low osmotic potential (-0.2 MPa) but decreased at more than -0.7 MPa. Seedling proline content appears not to be related to percentage germination but appears to be related to the decline in osmotic potential in germination media. Seed germination test at -0.7 to -1.2 MPa has the potential to be used as a vigor test in sweet corn. Keywords: Osmotic potential, germination, polyethylene glycol, corn, proline content African Journal of Biotechnology , Vol. 13(2), pp. 294-300, 8 January, 2014