Effect of drought stress and potassium foliarapplication on seed germination characteristics and seedling vigour of wheat (Triticum aestivum L.)

The effects of drought stress and potassium foliar application on seed germination and seedling vigour of wheat maternal plant, was studied. Field experiments conducted during growing season of 2011-2012 at two geographical zones: 1. Seed and Plant Certification and Registration Research Institute (SPCRI), Karaj- Iran 2. Agricultural and Natural Resources Research Center Yazd - Iran. The experiments were carried out using a split plot factorial based on a randomized complete blocks design with three replications. Treatments were three irrigation regimes; normal, mild stress (water withheld at the grain filling phase) and severe stress (water withheld at the ear emergence phase); potassium foliar treatments included, 0, 1.5% and 3.0% K2O applications and two wheat cultivars (Marvdasht and Pishtaz) and WS-82-9 line. Results indicated that seed germination percentage before seed cleaning significantly decreased by increasing drought stress. Maximum and minimum values of seed germination were obtained with WS-82-9 line under normal condition (%94.77) and Marvdasht under severe drought stress (%56.5), respectively. Seed germination after seed cleaning was increased by spraying with 3.0% K2O at Yazd (%10.47) and Karaj (%5.65). High and low seedling dry weight  values were attained with WS-82-9 line under normal irrigation and sprayed with 1.5 % K2O (0.018 gr) and Marvdasht under severe drought stress and no application of potassium (0.009 gr), respectively. It can be concluded that cultivating the WS-82-9  line and sprayed with 3.0% K2O are effective, especially in case of shortage irrigation at the end of plant life cycle.