EFFECT OF SEED PRIMING TREATMENT ON THE PHYSIOLOGICAL QUALITY OF NATURALLY AGED ONION (ALLIUM CEPA L.) SEEDS

The experiment was conducted to investigate the effect of priming treatments on the physiological parameters of naturally aged onion (Allium cepa L.) seed, six seed priming treatments viz., Control, Hydro priming followed by dry dressing with Thiram (2 g/kg), Hydration with GA(3)(50 ppm), Hydration with KNO3 (0.5% solution), Hydration with KH2PO4 (0.5% solution), and Biofertilizer (Azotobacter) were analyzed to identify the most suitable priming treatment. The standard seed germination, seedling length, seedling dry weight, seed vigour index-I & II and viability test (Tz test), decreased significantly, while electrical conductivity increased with the advancement of the ageing period. The field parameters viz., seedling emergence index and seedling establishment also decreased significantly with the natural ageing of seeds. The seed quality improvement through seed priming was noticed more in marginal seed lot, i.e., oneyear-old seed lot. Among various priming treatments, hydration with GA3 @ 50 PPM followed by biofertilizer, (Azotobacter) performed best in enhancing all seed vigour and viability characteristics and lowering the electrical conductivity of naturally aged onion seeds. In conclusion, the present study revealed that onion seed loses its viability rapidly under ambient storage conditions. Therefore, seed priming with GA(3) @ 50 ppm and biofertilizer, (Azotobacter) can be used effectively to enhance its vigour and viability. These priming treatments can aid to improve the quality of seed stored for one year, thus ensuring good plant stands from the stored seed of a poor storer crop.