2013 Volume 51 Issue 2 Pages 71-77
Appropriate methods for breaking down the seed hardness that interferes with the breeding of Pelargonium were carried out. Treatment with concentrated H2SO4 for 20 min for P. vitifolium seeds achieved a high germination rate of 90%, and with 60 min of treatment, the seeds of P.×domesticum achieved a germination rate of 70%. In the case of scarification by a homogenizer, with 5–10 min of treatment these two species both absorbed sufficient water and showed high germination rates. However, as the degree of seed hardness considerably differs among species (strains), it will be necessary to treat them accordingly in regard to length of treatment time. Germination was more effective when seed treated with concentrated H2SO4 or homogenizer was sown on vermiculite beds, compared with in petri dishes. The seeds of P. appendiculatum are not much harder than those of other Pelargonium species, and were germinated slowly at 10–15°C, after which healthy seedlings could be obtained. Regarding the other 5 species used in this trial, the germination rates were extremely haphazard according to species and sowing date (0–100%), indicating that plants under natural conditions need seed with the diversity to adapt to intense environmental changes.
