THE INFLUENCE OF THE POSITION OF THE SEED ON THE MOTHER PLANT ON SEED AND SEEDLING PERFORMANCE

Germination and seedling emergence studies were made on carrot seeds cv Royal Chantenay harvested from primary and secondary umbels when either ‘immature’ or ‘mature’. Germination at temperatures below 12°C and above 25°C was about 20% lower in ‘immature’ than ‘mature’ seeds, particularly from primary as opposed to secondary umbels.
Immature seeds from secondary umbels took c.6 days longer to germinate at 5°C and 2 days longer at 20°C than those from primary umbels.
Seedling weights about 20 days after 50% emergence were greater from seeds from primary than secondary umbels.
The increased variability in seedling weight found from seeds from secondary as opposed to primary umbels arose from the greater variability of individual seed weights.

Celery seeds harvested from four umbel positions on parent plants of cv Lathom Blanching also showed differences in weight and germination characteristics.
Although heavier seeds were produced from primary umbels than from other umbels these were less viable as measured by the germination percentage at 18°C in the light.
However, the viable seeds from primary and secondary umbels were less dormant than those from quarternary umbels.
Dormancy was measured by incubating the seeds in the dark at 18°C with various growth regulators.
Seeds from quarternary umbels showed little response to GA_4/7(2 x 10^-4M) as compared with ‘primary and secondary’ seeds but germinated completely when N⁶ benzyladenine (10^-4M) was used in combination with the GA_4/7. Seeds from quarternary umbels also had a lower high temperature limit for germination in the dark than did seeds from other umbels.

Symposium on Seed Problems in Horticulture

T.H. Thomas, D. Gray, N.L. Biddington

https://doi.org/10.17660/ActaHortic.1978.83.7