Germination of Lettuce Seeds at High Temperature after Seed Priming1

Abstract

The effects of water or 1% K 3 PO 4 priming at 5°, 15° and 25°C for short durations on ‘Minetto’ lettuce ( Lactuca sativa L.) seed germination at high temperatures were studied. Germination percentage and rate at 35° of seeds primed in K 3 PO 4 were significantly higher than that of seeds soaked in water. Aeration improved the results of priming at 15° and 25°. A priming temperature of 15° was generally best. The effects of light during priming of ‘Mesa 659’, ‘Minetto’ and ‘Ithaca’ seeds in water, K 3 PO 4 , polyethylene glycol (PEG) or PEG + K 3 PO 4 solutions at 15° for 6 or 9 hr and drying methods for primed seeds were also studied. Imbibition rates were higher with K 3 PO 4 . Primed seeds germinated more rapidly at 35° with K 3 PO 4 alone or in combination with PEG. Air drying of primed seeds was better than oven drying. Seed priming in light increased germination percentage and rate of ‘Minetto’ and ‘Ithaca’, although neither cultivar is photosensitive.