Epsilon Archive for Student Projects

Abstract

Over the years poor germination in the Rosa genus has been one of the biggest challenges.
As an important ornamental crop with high revenues crop breeders are challenged when
breeding new varieties. Low germination is suspected to be caused by a combination of several
factors such as seed dormancy, inbreeding depression, hybrid incompatibility and embryo
viability. Previous germination studies suggested various methods to increase germination
success, all of them rose genotype depended. This study focused on evaluating embryo
viability, seed morphology and investigating possible treatments to enhance germination.
Embryo viability was determined by the floatation method and confirmed by a tetrazolium
diagnostics test in three rose groups. The second experiment characterized seed morphology,
but could not identify a single seed trait responsible for seed viability. For the third experiment
germination success was investigated by testing treatments for breaking physical and
physiological dormancy as well as comparing three different stratification periods for
prolonged physiological dormancy. A selection of chemical, digestive, hormone, and microbial
treatments were used in an attempt to soften the pericarp and to promote germination. In
addition two mixed stratification strategies were applied to determine beneficial effects. Results
showed that embryo viability can be predicted by the flotation method for 80-100%. The effect
of several treatments on germination success in rose seeds was statistically insignificant.
However, despite the insignificant, treatment germination success was respectively lower in
comparison to the control. Mixed short and long stratification showed no different effect on
germination.