
Project
LWV23068 GREAT Chrysant: Genetics of REsistance Against Thrips in Chrysanthemum
Chrysanthemum is one of the most important ornamental plants in the world, but its cultivation relies on insecticide use to control pest infestations, such as thrips. Thrips visually damage chrysanthemum plants by feeding and transmit plant viruses. Pesticide use has negative impacts on beneficial insects and the environment and, therefore, needs to be reduced.
To minimize the use of insecticides in chrysanthemum cultivation without losses due to thrips infestations, chrysanthemum growers and breeders would benefit from varieties with thrips resistance. Previously, we have identified such host plant resistance to the thrips Frankliniella occidentalis in one Chrysanthemum x morifolium cultivar and identified putative metabolites leading to thrips resistance. In addition, we found resistance against multiple thrips species in a wild Chrysanthemum accession. In this project, we will study these identified resistant sources and elucidate the genetics and mechanism(s) of the resistance(s). First, we will perform QTL mapping in a segregating population derived from a cross of two Chrysanthemum x morifolium cultivars to identify QTL(s) involved in resistance against the thrips F. occidentalis. Simultaneously, we will develop an artificial feeding assay, to test the effect of individual or combined metabolites on the survival of thrips larvae. To further validate the effect of metabolites on thrips development, metabolomics analysis on the segregating population will be performed. Furthermore, the resistance to multiple thrips species previously identified in a wild Chrysanthemum accession will be validated and studied further. The resistance mechanism will be elucidated, and we will generate segregating population(s) to identify QTL(s). We will also determine the resistance of this accession to other thrips species, populations, and other pests. Identifying sources of broad-spectrum resistance in wild relatives of Chrysanthemum will help in making future varieties resilient potential invasive thrips. Knowledge on the genetics of this broad-spectrum resistance, specifically identifying thrips resistance QTLs and flanking markers, will allow to effectively introduce the resistance trait in cultivated chrysanthemums. This will ultimately contribute to more sustainable production of chrysanthemum with less input of pesticides.