© 2007 Heron Publishing—Victoria, Canada
A molecular marker associated with low-temperature induction of dormancy in red osier dogwood (Cornus sericea)
Erl Svendsen (1), Ron Wilen (2), Robert Stevenson (1), Rensong Liu (1) and Karen K. Tanino (1, 3)
1. Department of Plant Sciences, 51 Campus Drive, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada / 2. Department of Biology, University College of the Fraser Valley, Abbotsford, BC V2S 7M9, Canada / 3. Corresponding author (tanino@usask.ca) / Received January 6, 2006; accepted May 7, 2006; published online December 1, 2006
Summary
Dormancy induction in temperate deciduous plants is thought to be regulated by short photoperiods, but low temperature has
been shown to eliminate the short photoperiod requirement in northern ecotypes. An F2 population (191 plants) red osier dogwood
(Cornus sericea L.) derived from a polycross of an F1 population produced from reciprocal crosses of the parental clonal ecotypes, Northwest
Territories (NWT, 62° N) and Utah (42° N), was examined to identify molecular markers of temperature-induced endodormancy.
Dormancy induction curves were generated for each individual in the F2 population and a standard point prior to vegetative
maturity (i-VM) was inferred from the change in slope of the dormancy acquisition curve. Under Saskatoon, Saskatchewan field
conditions (52° N), the NWT ecotype entered i-VM on average 5–6 weeks before the Utah ecotype. Two sub-populations of the
F2 population were distinguishable based on VM acquisition on exposure to low temperature but not to short photoperiods. A
sequence characterized amplified region (SCAR) marker was developed that correctly (> 92%) identified individual plants within
the F2 subpopulation that were responsive to low-temperature induction of VM. Timing of bud break was strongly associated
with the timing of VM in the geographical ecotypes but not in the F2 population, indicating that these are separate traits
under genetic control.
Keywords:
bud break, ecotype, endodormancy, photoperiod, temperature, vegetative maturity.
