Abstract

Seed priming has become a common strategy for seed treatment which increases rate, percentage and uniformity of germination or emergence, especially under unfavourable environmental conditions. The most frequently used seed priming techniques involve polyethylene glycol (PEG), sodium chloride (NaCl), or potassium nitrate (KNO3). However, for the emergence or growth in conditions of high salinity it becomes necessary to improve on these techniques. Seeds of muskmelon were primed in darkness at 25degreesC for four days, in solutions with 150 mM of different N-form salts (NH4NO3; KNO3; (NH4)SO4) and NaCl. Seeds were then rinsed and dried at 25degreesC, and finally germinated in three levels of salinity (0.5; 2.5 and 5.0 dS m(-1)) for 38 hours. Germination and growth of the protused radicle were monitored each hour to determine the Germination Index (GI) and rates of germination and growth. All salt solutions except (NH4)(2)SO4) resulted in an improved germination rate, radicle growth and Germination Index. Seeds primed with NH4NO3 and KNO3 had greater resistance to higher salinity levels in germination solution, while better GI and rates of germination and growth compared to the control; (NH4)(2)SO4 and NaCl primed treatments. Detrimental effect on total seed germination was observed only on (NH4)(2)SO4 primed seeds.