Effect of seed priming on germination of cucumber seed

Abstract

The study to find out the optimum imbibition period for seed priming of cucumbers of cv. “Super Big” had 9 treatments. The treatments included non-primed seeds; seeds primed for 0.5, 1, 2, 4, 8, 16 h or until radical protrusion; and 1 min flash-hydrated seeds. For seed priming, the seeds were placed between moist floral foam blocks (FORACELL®) at 25oC and 90% RH. At the end of the imbibition period of a particular treatment, the seeds were dehydrated to their initial weights and kept in sealed plastic bags at 17oC. The seed germination test was separated into 2 experiments. The experiment under control or laboratory condition was conducted with 3 replications/treatment and 100 seeds/replication. The seeds were sowed in a medium consisting of sand, coir and rice husk charcoal (1:1:1 by volume) in the growth chamber (Contherm Phytotron®) at alternating temperatures of 30/20oC (8 h of light/16 h of darkness) and 60% RH. This germination test was done in August 2010 at the Department of Plant Science and Natural Resources, Faculty of Agriculture, Chiang Mai University. The experiment under field condition was conducted with 3 replications/treatment and 100 seeds/replication. The seeds were sowed on 1x3 m2 seed beds in December 2010 at Mae Hia Agricultural Research, Demonstrative and Training Center, Chiang Mai University. The results showed that seed hydration by the placement of seeds between moist floral foam blocks at 25oC caused the seeds to enter phase II of seed imbibition (seed moisture content was high but constant) at the 16th hour. Phase II ended at the 40th hour of imbibition period. Seed priming with 16 h imbibition period (early phase II) was able to enhance the germination percentage in the laboratory test. It also accelerated the first true leaf expansion of seedlings in the field test. It is possible that seed priming with imbibition periods longer than 16 h but not over 40 h may result in greater enhancements of seed quality.