Hydro- and osmopriming improve chickpea germination

The effects of different priming treatments and durations on germination percentage, speed, synchrony and thermal time requirement of the seeds of chickpea were investigated. Seeds were osmoprimed in four water potentials (-0.5, -1.0, -1.5 and -2.0 MPa) of polyethylene glycol (PEG) or in 4% mannitol in addition to hydropriming for 12 or 24 h at 25 +/- 1 degrees C in darkness. Following priming, the seeds were subjected to germination tests at ten different constant temperatures ranging from 5 to 32 +/- 0.5 degrees C. In general, there was no significant effect of priming treatments on germination percentage. However, compared to unprimed seeds, hydropriming and osmopriming treatments induced faster and more synchronous germination at all of the temperatures tested and also significantly decreased thermal time requirements. These reductions in thermal time requirements ranged between 18.1 degrees C d and 30.3 degrees C d for 50% germination. Seeds treated with water for 12 h generally produced the highest germination speed and the lowest thermal time requirement values. Among the osmopriming treatments, seeds treated with -0.5 MPa solution of PEG for 24 h gave the best results. Consequently, hydropriming for 12 h or osmopriming ( PEG -0.5 MPa) for 24 h may be recommended for a better germination of chickpeas under cold soil conditions.