Inclusion of Acetyl Salicylic Acid and Methyl Jasmonate into the Priming Solution Improves Low-temperature Germination and Emergence of Sweet Pepper

The effects of incorporating plant growth regulators into the priming solution on low temperature germination and emergence percentage performance of sweet pepper ( Capsicum annuum `Demre') seeds before and after seed storage were investigated. Seeds were primed in 3% KNO 3 solution for 6 days at 25 °C in darkness containing one of the following: 1, 3, 5, or 10 μ m methyl jasmonate (MeJA) or 0.05, 0.1, 0.5, or 1 m m acetyl salicylic acid (ASA). Following priming, seeds were either immediately subjected to germination and emergence tests at 15 °C or stored at 4 °C for 1 month after which they were subjected to germination test at 15 °C. Priming pepper seeds in the presence or absence of plant growth regulators in general improved final germination percentage (FGP), germination rate (G 50 ) and germination synchrony (G 10-90 ) at 15 °C compared to nonprimed seeds which had an FGP of 44%, G 50 of 7.3 days and G 10-90 of 7.3 days. Priming seeds in KNO 3 solution containing 0.1 m m of ASA resulted in the highest germination percentage (91%), fastest germination rate (G 50 = 2.2 days) and the most synchronous germination (G 10-90 = 6.1 days). Emergence percentages were the highest for the seeds primed in the presence of 0.1 m m ASA (85%) and 3 μ m MeJA (84%) while nonprimed seeds had an emergence percentage of 40%. Fastest emergence rates (E 50 ) were also obtained from seeds primed in KNO 3 supplemented with 3 μ m MeJA (E 50 = 15.2 days) and 0.1 m m ASA (E 50 = 15.2 days). Shoot fresh and dry weights of pepper seedlings were significantly affected by priming treatments and priming in the presence of 0.1 m m ASA resulted in highest seedling shoot fresh and dry weights. Although all priming treatments improved germination performance of pepper seeds at 15 °C following 1 month of storage, inclusion of 0.1 m m ASA into the priming solution resulted in the highest germination percentage (84%) and germination rate (G 50 = 3.8 days). These results indicate that priming seeds in 0.1 m m of ASA or 3 μ m MeJA incorporated into the KNO 3 solution can be used as an effective method to improve low temperature performance of sweet pepper seeds and that these seeds can be stored for 1 month at 4 °C and still exhibit improved germination performance at 15 °C.