Criteria to determine the duration of the germination test for seeds of 'mistol' (Ziziphus mistol Grisebach)

摘要

The International Rules for Seed Testing prescribes standardised germination conditions and the appropriate duration of germination tests for a large number of species, but many species are not included. This work assesses various criteria that may be employed to determine the time for the First and Final Counts of the germination test applied to "mistol" (Ziziphus mistol Grisebach), a forest tree species native to Argentina, not included in the Rules. The most appropriate day for a Final Count was found to be day 12 after sowing, since this is when the curve of germination stabilizes over time. The First Count should be carried out on day 8, the day on which the maximum number of normal seedlings is obtained within a 24 hours period and when 50% and 66% of the final germination is achieved. Furthermore. this is the minimum period required for seedlings to reach a stage of development for suitable evaluation.