| Abstract |
Chrysanthemum
is one of the most important ornamental crops worldwide. Cultivation of C
hrysanthemum
is affected by infestations of thrips, of which in Europe
Frankliniella occidentalis
is the most important species. Although genetic variation for thrips resistance in
Chrysanthemum
cultivars has been observed, no strong thrips resistance has been successfully introduced in breeding programmes. Crop wild relatives can be sources of resistance traits, but information on the thrips-resistance level of wild species in the
Chrysanthemum
genus or of species in the related genus
Artemisia
is not yet available. Therefore, we screened 47 accessions from 23
Chrysanthemum
species and related genera in whole plant assays for thrips population build-up and in leaf-disc assays for larval development and survival. We identified several wild
Chrysanthemum
and
Artemisia
accessions on which population build-up was reduced, survival was low, and development of larvae was inhibited. On five highly resistant accessions, larvae were impaired in their development at the first larval stage (L1), effectively interrupting the life cycle of thrips. Next, we investigated the possible role of T-shaped and glandular trichomes in thrips resistance and found a positive correlation between arrested development in the L2 stage and higher density of T-shaped trichomes. However, not all the resistant accessions showed higher trichome density, suggesting that the latter accessions contain other resistance mechanisms. The identified resistant and susceptible wild relatives of
Chrysanthemum
may be used in further studies to elucidate the mechanism and the genetics of thrips resistance, and resistant accessions could be used as sources of thrips resistance in
Chrysanthemum
breeding programmes.
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