Effect of seed moisture content at harvesting time and priming with polyamines on barley seed (Hordeum vulgare L. c.v Usef) germination and vigour after storage

This study was conducted to investigate the role of polyamines (PAs) as priming agents on  improving seed vigour with  different  moisture  content (Mc)(14,16,18%) under storage conditions in barley (Hordeum vulgare L.) c.v Usef. Experiments were conducted at the Seed and Plant Certification and Registration Research Institute 1n 2012 -2013. The seeds were hand harvested at three initial moisture contents including 18, 16, 14% using wet weight basis. The seed samples then were sealed in polythene bags and stored in conditioned storages and for 8 months. After that for seed priming, seeds were soaked in 20mg/L-1 (w/v) aerated solution of Spermine (Spm), Puterscine (Put), and Spermidine (Spd) and distilled water (W) for 16h at 20±2C°. After each treatment, seeds were dried to original moisture level in forced air and sealed in polythene bags, stored in a conditioned storage again for one month. Experimental units were arranged as a completely randomized design with four replications after harvesting time and one month conditioned storage after treatment. The result indicated that 18% MC improved the germination percentage and seedling vigour compared to 16 and 14 % MC. Also after 8 month storage, 18% Mc had the highest germination percentage and seedling vigour. The electrolyte leakage decreased in seeds with 18% MC compared to 16 and 14% MC. Also seed treatments significantly increased the seed viability and germination percentage, whereas, mean germination time and electrical conductivity were reduced in all seed treatments. Meanwhile, maximum germination percentage was detected for seed Spm seed treatment and 18% MC. Generally by decreasing moisture content of seed and delay in harvesting time, seedling vigour decreased and the optimum moisture content and seed treatment were  18% and Spm, respectively.