Zinnia seed harvest time affects germination and plant growth.

摘要

Seeds of Zinnia violacea cultivars Kumamotonokagayaki (Kk), Goldenball (Gb) and Purple Gem (PG) were harvested at various stages of maturity and subsequent seed and plant performance were evaluated. The largest increase in ovule or embryo length andwidth occurred from 0 to 10 days after pollination (DAP). The seed weight remained constant beyond 23, 25 and 30 DAP for Kk, Gb, and PG, respectively. The pericarp colour was completely green in seeds harvested 20 DAP, while those harvested from 30 to 35 DAP were a mixture of green and brown. Pericarp colour change from green to brown was not a reliable index for deciding when to harvest. The percentage germination increased as seed harvesting was delayed from 10 to 19 DAP for all cultivars. From 20 to40 DAP, germination was unaffected and was >90%, while the rate of germination as measured by days to visible germination decreased slightly. Seeds harvested 20-40 DAP produced plants with uniform growth and quality characteristics. Considering a 20- to30-day difference between the first and last floret opening in a capitulum, capitula should be harvested 50 days after anthesis for good seed quality and to prevent shattering.