Abstract
About one third of all orchid species are deceptive, i.e., not providing any reward
to their pollinator. Such species often have lower visitation rates compared to rewarding
relatives. This could result in lower levels of geitonogamous selfing and thus would
provide an advantage in term of progeny fitness through inbreeding avoidance. This
hypothesis could be tested by comparing the level of inbreeding depression between
deceptive and rewarding orchids. However, due to the difficulty to raise orchids from
seeds, few studies of inbreeding depression are available, and most are focused on
very early life stages, such as seed mass or embryo viability. Here, we present the
results from an experimental investigation of inbreeding depression in the deceptive
flower-colour dimorphic Dactylorhiza sambucina, from in vitro cultivation to greenhouse soil transplantation. We found strong inbreeding depression
at all recorded stages (i.e., germination and survival), with estimates ranging from
0.47 to 0.75. Our study finally proposes a simple and suitable experimental protocol
to raise orchids from seeds with high germination rates.
Key words
Inbreeding depression -
in vitro cultivation - deceptive orchid - seed germination -
Dactylorhiza sambucina.
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N. Juillet
Department of Ecology and Evolution
University of Lausanne
1015 Lausanne
Switzerland
Email: nicolas.juillet@unil.ch
Editor: F. Salamini
