OPPORTUNITIES TO BREED FOR BROAD MITE RESISTANCE IN RHODODENDRON SIMSII HYBRIDS

Broad mites, Polyphagotarsonemus latus Banks, are a key pest in many ornamental plants including pot azalea, Rhododendron simsii hybrid.
These minute mites (<200 µm) cause browning and curling of leaves and flowers leading to economic losses as damaged plants are unmarketable.
Development of resistant cultivars might lead to a sustainable solution in controlling this pest.
We studied the response upon a broad mite infestation in R. simsii by means of gene expression.
Data showed the induction of the jasmonic acid defence pathway in response to a broad mite infestation.
Furthermore, an oxidative stress response was observed in infested plants when compared to control plants.
Scanning electron microscopy of leaf morphology in eight R. simsii cultivars with a known susceptibility for broad mites revealed the presence of different trichome types.
Short trichomes with a sticky end were seen in resistant or more tolerant genotypes.
The outcome of this study might provide new insights in breeding for resistance against this pest in azalea.

XXV International EUCARPIA Symposium Section Ornamentals: Crossing Borders

G. Luypaert, J. Van Huylenbroeck, J. De Riek, E. Mechant, E. Pauwels, P. De Clercq

jasmonic acid, phytohormone, Polyphagotarsonemus latus, pot azalea, trichome

https://doi.org/10.17660/ActaHortic.2015.1087.65